JP5059506B2 - Plain bearing - Google Patents

Description

  The present invention, like a bearing of a construction machine, has a relatively large size and a high surface pressure acting on an inner peripheral surface as a bearing surface, and the shaft slides relative to the bearing at a relatively low speed. The present invention relates to a slide bearing that is suitably used as a bearing.

  Generally, the joint portion of an arm provided in a construction machine such as a hydraulic excavator is such that the shaft inserted into the bearing repeatedly swings relatively within a range of a certain rotation angle, and is higher than 20 MPa. Receive surface pressure. For this reason, as this type of bearing, a sliding bearing using a material having excellent wear resistance is used, and lubricating oil, grease, wax, or the like having high viscosity is supplied to the sliding surface. In such a sliding bearing, even if it is subjected to a high surface pressure, the metal contact is suppressed and it is difficult to wear, and the lubricating oil is sufficiently supplied to the sliding surface in order to exert a smooth bearing action. Is required. For this reason, a material such as a heat treated product of carbon steel or high-strength brass is applied as a material for the slide bearing, and in recent years, application of a sintered material has also been realized (see Patent Document 1).

  The above materials and lubricants are excellent, but for the purpose of further extending the life of the bearing, a plurality of inclined grooves extending in the direction intersecting the circumferential direction are formed on the inner peripheral surface of the bearing, and the inclination thereof A sliding bearing is also applied in which lubricating oil stored in the groove is supplied to the sliding surface as the shaft rotates (see Patent Document 2).

JP 2003-222133 A JP 2006-009846 A

  The inclined groove of the bearing described in Patent Document 2 is a sliding surface of a mountain portion adjacent to the rotation direction of the shaft, in which the lubricating oil stored in the inclined groove is drawn by the suction action generated by the rotating shaft. It is said that the amount of lubricating oil stored is increased and the supply amount is sufficient. However, it has been found that under certain conditions, the lubricating oil may not be sufficiently supplied to the sliding surface. The reason was presumed that the amount of lubricating oil supplied from the inside of the inclined groove to the sliding surface of the adjacent peak portion may be insufficient to lubricate the entire sliding surface. As a result, it was found that there was a portion where the amount of lubricating oil was insufficient on the sliding surface, and metal contact was made at that portion, and wear of the bearing progressed.

  In addition, this type of bearing is often used with the axial direction set sideways. At this time, since the shaft rotates in the bearing, the lubricating oil is carried in the rotational direction of the shaft. When the rotation of the shaft is stopped, the lower portion of the bearing receives a high surface pressure due to gravity. Therefore, if the amount of lubricating oil is insufficient, the shaft and the bearing are in metal contact. For this reason, when the lubricating oil is carried to the upper part of the bearing, the lubricating oil carried to the upper part of the bearing must be returned to the lower part of the bearing because the lubricating oil in the lower part of the bearing may be insufficient when the rotation of the shaft is stopped. However, in the slide bearing described in the above document, the lubricating oil is unlikely to return to the lower portion of the bearing, so that when the shaft stops rotating, the amount of lubricating oil is insufficient at the lower portion of the bearing, and the shaft and the bearing may come into metal contact.

  Therefore, according to the present invention, the lubricating oil stored in the plurality of grooves extending in the direction intersecting the circumferential direction is sufficiently supplied to the entire sliding surface of the mountain portion adjacent to the groove as the shaft rotates. It is an object of the present invention to provide a sliding bearing that can provide an excellent lubricating effect and that can prevent metal wear even when subjected to high surface pressure and is hard to wear and can exhibit a smooth bearing action over a long period of time.

In the present invention, a shaft inserted into a shaft hole is rotatably supported, and a plurality of linear inclined grooves extending in a direction crossing the circumferential direction are spaced apart in the circumferential direction on an inner peripheral surface on which the shaft slides. A sliding bearing in which lubricating oil is supplied to these inclined grooves, wherein the inclined grooves are formed under the following conditions (A) to (D):
It is inclined in the range of 15 ° to 50 ° with respect (A) direction perpendicular to the circumferential direction.
(B) The circumferential groove width B is 1.19 to 5 mm.
(C) The width A in the circumferential direction of the sliding surface, which is the surface of the crest between adjacent inclined grooves, is 1 to 7 mm.
(D) Ratio A / B of the width A of the sliding surface of the peak portion and the groove width B is 0.5 to 4.05 .
Further, at least a pair of annular grooves are formed on the inner periphery and the outer periphery of the slide bearing, and the annular grooves formed on the inner periphery communicate with the inclined grooves, and the pair of annular grooves are mutually connected. At least one through-hole to be communicated is formed.

  Among the above conditions, the condition (A) is that the inclination angle and inclination of the inclined groove are such that the imaginary line orthogonal to the sliding direction intersects the sliding surface and the inclined groove at any position on the inner circumference of the bearing. The width of the groove and the width of the sliding surface are set, and no matter what part of the inner circumference of the bearing is subjected to the shaft load, the shaft surface always contacts both the sliding surface and the inclined groove, and the sliding surface is lubricated. This is a condition for obtaining an effect of constantly supplying oil.

  In addition, among the above conditions, due to the synergistic action satisfying (B) to (D), sufficient lubricating oil is supplied to the sliding surface even if the inclined groove according to the present invention is thinner than the conventional one. With such an inclined groove, the amount of lubricating oil that is drawn out of the groove with the rotation of the shaft and flows to the sliding surface of the adjacent peak portion is ensured over the entire peak portion. A sufficient lubricating effect can be obtained. That is, these conditions are optimized to sufficiently lubricate the sliding surface by the inclined grooves formed on the inner peripheral surface.

  That is, the sliding bearing of the present invention is an improvement of the sliding bearing of Patent Document 2, and a sufficient amount of lubricating oil was supplied to the entire sliding surface under the above conditions (B) to (D). Is. In addition, by optimizing the circumferential width A of the sliding surface and the ratio A / B of the width A of the sliding surface and the groove width B, the sliding bearing of the present invention is more than the conventional sliding bearing. The groove width B in the circumferential direction can be narrowed, the inclination angle of the inclined groove can be set to be enlarged, and the surface pressure applied to the sliding surface is reduced. The groove width B and the sliding surface width A referred to in the present invention are the widths in the circumferential direction as described above, and are not the widths in the direction orthogonal to the extending direction of the grooves.

  Furthermore, in the plain bearing of the present invention, a pair of annular grooves communicated by a through hole are formed on the inner periphery and the outer periphery. Due to the annular groove and the through hole, the lubricating oil stored in the upper part of the bearing by the rotation of the shaft can be smoothly returned to the lower part of the bearing that receives a high surface pressure when the rotation of the shaft is stopped. For this reason, lubricating oil can be evenly supplied to the sliding surface, and metal contact at the bottom of the bearing due to lack of lubricating oil when the rotation of the shaft is stopped can be suppressed. As a result, the sliding surface can be lubricated more efficiently, and the lubrication period of the lubricating oil can be extended, for example, twice or more, and the life of the slide bearing can be extended.

  Moreover, the slide bearing of the present invention is made of a sintered alloy, and the depth d of the inclined groove of the slide bearing is preferably 0.1 to 3 mm. By manufacturing the sliding bearing with a sintered alloy, the inclined groove can be easily formed when the metal powder as a raw material is formed using a mold, and therefore, it can be efficiently produced. Further, when the inclined groove has the depth of the above condition, the lubricating oil can be reliably stored in the inclined groove, and the lubricating oil can be sufficiently supplied to the sliding surface.

  According to the present invention, the groove for lubricating oil storage formed on the inner peripheral surface of the bearing, the inclination angle with respect to the direction orthogonal to the circumferential direction, the groove width in the circumferential direction, the circumferential width of the sliding surface between the grooves, The ratio of the circumferential width between the groove and the sliding surface, and the area ratio of the inner peripheral surface are optimized so that sufficient lubricating oil is supplied from the groove to the entire sliding surface. Even when subjected to a high surface pressure, the metal contact is suppressed, and it is difficult to wear and a smooth bearing function can be exhibited. Also, by forming a pair of annular grooves communicating with through holes on the inner and outer peripheries of the slide bearing, the bearing that receives high surface pressure when the rotation of the shaft stops the lubricating oil stored in the upper part due to the rotation of the shaft. It can be smoothly returned to the lower part. As a result, it is possible to lubricate the sliding surface more efficiently, extend the lubrication time of the lubricating oil, and increase the life of the slide bearing.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 show a cylindrical plain bearing of one embodiment, FIG. 1 is a perspective view, and FIG. 2 is a side view. The upper side of FIG. 2 represents a cross-sectional view of the side surface of the bearing 1. FIG. 3 is a development view of the inner peripheral surface 10 of the bearing 1. A plurality of linear inclined grooves 12 extending in a direction intersecting the circumferential direction (direction indicated by arrow R in FIG. 2) are formed on the inner peripheral surface 10 of the bearing 1 at equal intervals in the circumferential direction. Yes. Further, annular inner circumferential grooves 15 and outer circumferential grooves 16 extending in the circumferential direction are formed on the inner circumference and the outer circumference of the bearing 1 one by one over the entire circumference. The inner circumferential groove 15 and the outer circumferential groove 16 are formed at substantially the center in the axial direction of the bearing 1. The bearing 1 is formed with a through hole 17 that communicates the inner and outer circumferential grooves 15 and 16. In this case, a total of two through holes 17 are formed, one at a position that is 180 ° out of phase with each other.

  4 and 5 are sectional views showing a state in which the shaft 20 is rotatably inserted into the shaft hole 11 of the bearing 1, FIG. 4 is a sectional view showing the inclined groove 12, and FIG. 5 is an inner circumferential groove 15 and an outer circumferential groove. FIG. The shaft 20 swings while sliding on the sliding surface 14 which is the surface of the peak 13 between the inclined grooves 12.

  The bearing 1 has an inner peripheral surface with a diameter of about 20 to 150 mm and an axial height of about 20 to 150 mm. The joint 1 of an arm provided in a construction machine such as a hydraulic excavator mainly extends in the axial direction laterally. The swinging motion in which the load of the shaft 20 disposed in the lateral direction is supported by the inner peripheral surface 10 and the maximum sliding speed is about 20 to 50 mm / s under a high surface pressure of 20 MPa or more. Is used. Such a swinging motion of the shaft 20 operates so as to stop at both ends of the swinging angle and switch the motion direction. That is, it is operated while repeating a stationary state and a sliding state. Therefore, in this type of plain bearing, it is required to reduce both the dynamic friction coefficient and the static friction coefficient. In particular, since the static friction coefficient is larger than the dynamic friction coefficient, it is important to reduce the static friction coefficient in order to prevent metal contact.

  The bearing 1 of the present embodiment is an improvement of the above-described sliding bearing of Patent Document 2, and, like the sliding bearing of Patent Document 2, lubricating oil is applied to the inclined groove 12 provided on the inner peripheral surface 10 of the bearing 1. The lubricating oil is stored and drawn out by the suction action generated by the rotating shaft, and flows to the sliding surface 14 which is the surface of the mountain portion 13 adjacent to the rotating direction of the shaft 20. It obtains a lubricating action.

  Further, the bearing 1 is such that an imaginary line orthogonal to the sliding direction of the shaft 20 (the direction of the arrow R in FIG. 2) intersects the inclined groove 12 and the sliding surface 14 at any position on the inner periphery of the bearing. The inclination angle θ of the inclined groove 12, the width of the inclined groove 12, and the width of the sliding surface 14 are set, and the shaft surface always slides with the inclined groove 12 regardless of which part of the inner periphery of the bearing is subjected to the load of the shaft 20. In contact with both of the surfaces 14, the lubricating oil is constantly supplied to the sliding surface 14. In addition, the inclined groove 12 acts as a refuge for foreign matter when foreign matter enters from the outside of the bearing 1, and has an effect of preventing foreign matter from entering the sliding surface 14 and preventing wear due to the foreign matter. .

  In the inclined groove 12 having the above action, if the interval between the inclined grooves 12, that is, the width of the sliding surface 14 is wide, the surface pressure received by the sliding surface 14 decreases. Good lubricating oil will not be supplied to Further, if the width of the sliding surface 14 is narrow, it becomes easy to supply the lubricating oil, but the area of the sliding surface 14 that receives the load of the shaft 20 decreases, so the surface pressure that the sliding surface 14 receives increases. Therefore, metal contact is likely to occur. As a result of studies by the present inventors from these viewpoints, when the circumferential width A of the sliding surface 14 (sliding surface width A) is 1 to 7 mm, the surface pressure received by the sliding surface 14 is significantly increased. Thus, it was found that good lubricating oil can be supplied to the entire sliding surface 14. Therefore, in the bearing 1 of the present embodiment, the width A of the sliding surface 14 is 1 to 7 mm.

If the width of the inclined groove 12 is too narrow, the amount of lubricating oil stored becomes insufficient, and sufficient supply of lubricating oil to the sliding surface 14 cannot be achieved. On the other hand, when the width of the inclined groove 12 is too wide, the lubricating oil is liable to leak and the area of the sliding surface 14 that receives the load of the shaft 20 decreases, so that the surface pressure received by the sliding surface 14 increases. This facilitates metal contact and increases the dynamic friction coefficient. As a result of examination from these viewpoints, when the width A of the sliding surface 14 is set as described above, the circumferential width B (groove width B) of the inclined groove 12 is 1.19 to 5 mm, from Patent Document 2. However, it has been found that even if it is set narrowly, the lubricating oil can be sufficiently supplied to the sliding surface 14 and the dynamic friction coefficient can be reduced. From this, the bearing 1 of this embodiment sets the groove width B to 1.19 to 5 mm. Further, in the bearing 1, even when the lateral width B is set to be narrower than that of Patent Document 2, as described above, the surface pressure that the sliding surface 14 receives can be reduced more effectively than that of Patent Document 2. In addition, good lubricating oil can be supplied to the entire sliding surface 14.

  Further, the width A and the groove width B are closely related to supplying sufficient lubricating oil to the entire sliding surface 14. That is, if the groove width B is set wide within the above range, the amount of lubricant stored in the inclined groove 12 increases, so the amount of lubricant that can be supplied to the sliding surface 14 increases, and the width A is set large. Thus, the surface pressure received by the sliding surface 14 can be reduced. On the other hand, if the groove width B is set narrow, the amount of lubricating oil stored in the inclined groove 12 decreases, so the amount of lubricating oil that can be supplied to the sliding surface 14 decreases, and the width A must be set narrow. . Therefore, in order to obtain a good lubrication state, it is necessary to set the width A and the groove width B to an appropriate ratio.

From this viewpoint, in the bearing 1 of the present embodiment, the width A and the groove width B are set as described above, and the ratio A / B between the width A and the groove width B is 0.5 to 4.05 . Set to range. If the ratio A / B between the width A and the groove width B is within the above range, the surface pressure received by the sliding surface 14 does not become excessive, and a good lubrication state over the entire sliding surface 14 can be obtained, resulting in dynamic friction. It is possible to obtain a slide bearing that can reduce the coefficient, and that is hard to wear and that exhibits a smooth bearing action over a long period of time. On the other hand, when the ratio A / B between the width A and the groove width B is less than 0.5, the width A is too small compared to the groove width B, and the surface pressure received by the sliding surface 14 is excessive. Metal contact tends to occur, and in some cases, deformation such as buckling may occur. Further, if A / B exceeds 4.05 , the width A becomes too large compared to the groove width B, and it becomes difficult to obtain a good lubrication state over the entire sliding surface 14, and metal contact occurs. It becomes easy and wear may occur.

  The bearing 1 can be slid without any significant increase in the surface pressure received by the sliding surface 14 by optimizing the width A, the groove width B, and the ratio A / B of the width A and the groove width B as described above. Good lubricant oil supply to the entire area of the surface 14 has been achieved, thereby suppressing the occurrence of metal contact and reducing the coefficient of dynamic friction, realizing a long-lasting smooth bearing action that is difficult to wear. In addition, as a result of the satisfactory supply of lubricating oil to the entire sliding surface 14 as described above, the shaft 20 and the sliding surface 14 of the bearing 1 are in contact with each other at the time of starting and at rest at both ends of the swing angle. In the meantime, the oil film of the lubricating oil is maintained, and the coefficient of static friction is reduced, and the metal contact during the transition from the stationary state to the moving state is prevented.

Even when the size of each of the width A and the groove width B and the ratio A / B are set as described above, when the inclination angle θ of the inclined groove 12 is too small, it contacts the shaft 20 of the inner peripheral surface 10. In this portion, the number of the inclined grooves 12 and the number of the sliding surfaces 14 that the contact portion crosses are reduced, and the length of the inclined grooves 12 and the length of the sliding surface 14 are increased, so that the entire contact portion is lubricated. The state becomes uneven. When the inclination angle θ of the inclined groove 12 exceeds a certain level, the number of inclined grooves 12 and the number of sliding surfaces 14 that cross the contact portion increase, and the length of the inclined grooves 12 and the length of the sliding surface 14 are appropriate. Thus, a good lubrication state over the entire sliding portion can be obtained. On the other hand, if the inclination angle θ of the inclined groove 12 is too large, the number of the inclined grooves 12 and the number of sliding surfaces 14 that cross the contact portion further increase, but the lubricating oil flows along the inclined groove 12, Supply to the sliding surface 14 becomes insufficient. These are the inclination angle θ of the inclined grooves 12 in view is appropriate 15 to 50 °, good Mashiku is preferred exhibits a stable value of friction coefficient is low at approximately 20 to 40 °. That is, in the present embodiment, the size of each of the width A and the groove width B and the ratio A / B thereof are set optimally, so that the inclination angle of the inclined groove 12 can be applied as compared with Patent Document 2. As a result, the degree of freedom of design of the slide bearing is improved.

  The grooves may be equally spaced as shown in FIGS. 1 to 3, but are formed so as to be within the range of the ratio A / B of the width A, groove width B, and sliding surface width A to groove width B described above. It does not have to be equally spaced. Further, if the depth d of the inclined groove 12 is shallow, the amount of lubricating oil stored is small, and the lubricating oil cannot be supplied to the entire sliding surface 14, so it is necessary to set it to 0.1 mm or more. On the other hand, if the depth d of the inclined groove 12 is made too deep, the height of the sliding surface 14 with respect to the bottom portion of the inclined groove 12 becomes large, and the sliding surface under the operating environment of high surface pressure and oscillating motions. There is a risk of buckling of moving parts. For this reason, the depth d of the inclined groove 12 should be stopped at 3 mm or less.

  In addition, although the cross-sectional shape of the inclined groove 12 is a rectangular shape in the illustrated example, an arbitrary shape such as an arc shape or a U shape is selected, but lubricating oil is supplied to the sliding surface during the swinging motion of the shaft. It is preferable to use a V-shape that is easy to handle or a trapezoidal shape having a large upper surface width. Further, it is desirable that the corner portion that transitions from the inclined groove 12 to the sliding surface 14 between the inclined grooves 12 is chamfered to improve the fluidity of the lubricating oil and reduce the friction. It is desirable that the cross-sectional shape is circular or U-shaped with chamfering.

  As described above, the bearing 1 of the present embodiment is formed with the inner peripheral groove 15 and the outer peripheral groove 16 on the inner periphery and the outer periphery, and the inner peripheral groove 15 and the outer peripheral groove 16 are communicated with each other through the through hole 17. Yes. The inner circumferential groove 15, the outer circumferential groove 16, and the through hole 17 have a function of supplying lubricating oil evenly to the inclined groove 12 described above. In other words, as described above, the bearing 1 is oscillated while receiving the load of the shaft 20 arranged in the lateral direction with the axial direction being lateral, but from the lubricating oil transferred by the oscillating motion or the bearing 1. The oozed lubricating oil is collected at the bearing lower portion (lower side in the figure) through the inner circumferential groove 15, outer circumferential groove 16 and through-hole 17, supplied to the inclined groove 12 at the lower portion of the bearing, and loaded on the shaft 20. This contributes to the supply of lubricating oil to the sliding surface 14 that receives the lubricating oil. The inner circumferential groove 15 and the outer circumferential groove 16 are preferably used as a pair at a portion having the same length in the axial direction in terms of forming the through hole 17. A plurality of inner circumferential grooves 15 and outer circumferential grooves 16 may be provided when the axial length of the bearing 1 is long.

  As shown in FIG. 5, the through hole 17 that connects the inner circumferential groove 15 and the outer circumferential groove 16 supplies the lubricating oil recovered by the outer circumferential groove 16 to the inner circumferential groove 15 and the inclined groove 12. In order to obtain this action efficiently, the through-hole 17 needs to be arranged at the lowermost part. If the through holes 17 are, for example, as many as 5 to 8 and are evenly arranged, any of the through holes 17 will be positioned on the lower side, so that the phase of the through hole 17 is changed when the bearing 1 is assembled. This is preferable because it does not require attention.

The lubricating oil is the same as the conventional one in that machine oil (industrial lubricating oil), grease, a mixture of wax and oil, etc. can be used, but the inclination angle θ is set so that the inclined groove 12 is in the above range. By forming the width A, the groove width B, and the ratio A / B between the width A and the groove width B, it is possible to use a lubricating oil having a wider viscosity range than the conventional one. For example, a machine oil that can be used in a simple cylindrical plain bearing that does not form an inclined groove as in Patent Document 1 has a kinematic viscosity of 40 ° C. or higher of about 414 to 1100 mm ² / s (ISO VG of ISO VG 460 to 1000) It is only equivalent). However, in the bearing 1 in which the inclined groove 12 having the above condition range is formed, it is possible to use a bearing having a kinematic viscosity at 40 ° C. in the range of 1650 mm ² / s (equivalent to ISO VG 1500). Even if this is a highly viscous lubricating oil that does not flow easily, in the bearing 1, the inclination angle θ of the inclined groove 12, the width A, the groove width B, and the ratio A / B of the width A and the groove width B are within the above range. This is because the supply state of the lubricating oil to the sliding surface 14 is improved. Such a high-viscosity lubricating oil hardly flows, but can form a strong oil film. Therefore, in the bearing 1 of the present embodiment, by using a high-viscosity lubricating oil, it is possible to further prevent the occurrence of wear by preventing metal contact and extend the bearing life. In addition, in the case of a simple cylindrical slide bearing that does not form an inclined groove, grease can only be used with a blending consistency of about 205-265 (No. 2-4 consistency specified in JIS K2220). In No. 1, it is possible to use up to about 130 (No. 5 consistency).

  The material of the bearing 1 is not particularly limited, and a melted material such as heat-treated carbon steel or high-strength brass can be used. In this case, the inclined groove 12 can be formed by means such as casting, extrusion, or machining. A sintered material can also be used as the material of the bearing 1. The sintered material is a material obtained by sintering a molded body obtained by compressing a raw material powder into a mold and then using a punch from above and below, and the male die of the inclined groove 12 is used as a core rod. Forming it is preferable because it can be easily applied. Sintered materials are also recommended because they have a wide variety of compositions compared to melted materials, and can easily obtain metallographic materials that cannot be obtained with melted materials. Further, the sintered material recommended for the bearing 1 is the same as that described in Patent Document 2.

  According to the bearing 1 of the present embodiment, when the shaft 20 rotates, the lubricating oil stored in the inclined groove 12 is drawn out from the inclined groove 12 and flows in the rotational direction of the shaft 20, and the sliding surface 14. And the sliding with the shaft 20 is lubricated. Lubricating oil that flows from the inclined groove 12 to the sliding surface 14 when the inclined groove 12 satisfies the above-described inclination angle θ, width A, groove width B, and ratio A / B of the width A and groove width B. As for the amount of, an amount extending over the entire sliding surface 14 is secured. Further, the lubricating oil that has spread over the entire area of the sliding surface 14 is retained even when it is stationary. Therefore, a sufficient lubricating effect can be obtained, and the static friction coefficient can be reduced together with the dynamic friction coefficient. Further, since the lubricating oil transferred by the swinging motion by the inner and outer circumferential grooves 15 and 16 and the through-hole 17 formed on the inner and outer circumferences of the bearing 1 is collected below the bearing and supplied to the inclined groove 12, the above-described dynamic friction is achieved. The effect of reducing the coefficient and the coefficient of static friction can be maintained over a long period of time. Due to these effects, the bearing 1 of the present embodiment is a bearing that maintains a lubricating effect over a long period of time even under a high surface pressure, is less likely to wear, and has improved durability. Further, when the lubricating oil in the vicinity of the sliding surface 14 is consumed, the inner peripheral groove 15 and the outer peripheral groove 16 collect and supply the lubricating oil in the inclined groove 12 at a position away from the sliding surface 14 from the inner peripheral groove 15. Therefore, the lubrication period of the lubricating oil can be extended more than twice.

Next, examples that demonstrate the effects of the present invention will be described.
[First embodiment]
To 100 parts by mass of raw material powder obtained by adding 18% by mass of atomized copper powder and 0.8% by mass of graphite powder to atomized iron powder, 0.5 parts by mass of zinc stearate powder is further added as a molding lubricant. The mixed powder was compression molded into a cylindrical shape having an outer diameter of 95 mm, an inner diameter of 80 mm, and a height (axial length) of 80 mm. This molded body was sintered in a reducing gas at 1120 ° C., subsequently heated to 850 ° C., then oil-quenched, and tempered at a temperature of 180 ° C. to prepare a bearing sample.

  With respect to the produced bearings, the number of inclined grooves, the width and the depth of the conditions shown in Table 1 are set so that the inclination angle with respect to the direction orthogonal to the circumferential direction (sliding direction) is 20 °, and the inner peripheral surface is machined by machining. An inclined groove having a trapezoidal cross section was formed. Further, an annular inner circumferential groove and an outer circumferential groove having a width of 5 mm and a depth of 1 mm were formed on the inner and outer circumferences by machining, and two through holes communicating with the inner and outer circumferential grooves were formed at equal intervals. Next, these bearings were vacuum impregnated with a machine oil having a kinematic viscosity of 460 mm 2 / s at 40 ° C., and the number of inclined grooves shown in Table 1, the width A of the sliding surface which is the surface of the ridge, the groove width B of the inclined grooves, Bearings having the ratio of the sliding surface width A to the groove width B, the area ratio and the depth of the inclined grooves (sample numbers 01 to 40) were produced. The sliding surface width A and groove width B are circumferential widths, not widths perpendicular to the grooves. In addition, the value shown by the underline in Table 1 shows that it deviates from the scope of the present invention.

  The prepared bearing samples 01 to 38 are fixed in the housing so that the through-holes are arranged vertically below the shaft, and mixed with the inner peripheral surface of the bearing and the surface of the steel shaft that has been quenched and polished. Grease with a degree of 280 (lithium grease No. 2) was applied, and the shaft was inserted into the shaft hole of each bearing. The clearance between the inner peripheral surface of the bearing sample and the shaft is about 300 μm. Next, the shaft was rocked at a sliding speed of 0.5 mm / min within a range of 10 ° while applying a load of 650 N in the radial direction. In addition, when rocking | fluctuating, it was made to rest each for 0.5 second in the terminal position of pendulum movement. At this time, the values (average values) of the static friction coefficient and the dynamic friction coefficient obtained from the torque values measured by the torque sensor are also shown in Table 1.

Below is a discussion of the test results.
(1) Influence of sliding surface width A: See FIG. 6 The bearings of sample numbers 01 to 07 in Table 1 have a ratio (A / B) of the sliding surface width A to the inclined groove width B (A / B). The effect was examined by changing the width A while assuming the same. In these samples, in the bearing of sample number 01 where the sliding surface width A is less than 1 mm, the sliding surface width A is too small, so that the load cannot withstand the load and the peak portion buckles and deforms. The groove width B becomes smaller and the supply of lubricating oil becomes insufficient, and the values of the static friction coefficient and the dynamic friction coefficient are increased. On the other hand, the bearing of sample number 02 having a sliding surface width A of 1 mm was able to withstand the load sufficiently, and no deformation of the peak portion was observed. In addition, since the width A of the sliding surface is small, the lubricating oil can be sufficiently supplied from the inclined groove, and the static friction coefficient and the dynamic friction coefficient are also small. In addition, as the sliding surface width A increases, the static friction coefficient and the dynamic friction coefficient tend to gradually increase. However, the sliding surface width A maintains a sufficiently small value up to 7 mm (sample No. 06). ing. However, in the bearing of Sample No. 07 having a sliding surface width A exceeding 7 mm, the sliding surface width A is large and the supply of lubricating oil from the inclined groove is insufficient, so that both the static friction coefficient and the dynamic friction coefficient are both. It is increasing rapidly. From these facts, it is understood that the range of 1 to 7 mm is appropriate for the width A of the sliding surface.

(2) Influence of groove width B: see FIG. 7 The bearings of sample numbers 08 to 17 in Table 1 have the ratio (A / B) of the width A of the sliding surface to the groove width B of sample numbers 08 to 12. The effect was examined by changing the groove width B after making the bearings substantially the same for the bearings of Sample Nos. 13-17. In these samples, in the bearing of sample number 08 in which the groove width B is less than 1.19 mm, the lubricating oil supplied to the sliding surface becomes insufficient even though the width A of the sliding surface is sufficient, The coefficient of friction shows a large value. On the other hand, in the bearing of the sample number 11 with the groove width B of 1.19 mm, the static friction coefficient and the dynamic friction coefficient are drastically decreased because the groove width B is sufficiently large and sufficient lubricating oil can be supplied to the sliding surface. Yes. Further, in the range where the groove width B is 1.19 to 5 mm, both friction coefficients are low and stable values. However, in the bearing of sample number 17 where the groove width B exceeds 5 mm, the ratio (A / B) of the width A of the sliding surface to the groove width B is constant. Sufficient lubricating oil is not supplied to the moving surface, and both the coefficient of static friction and the coefficient of dynamic friction increase rapidly. From these, it is understood that the groove width B is appropriately in the range of 1.19 to 5 mm.

(3) Influence of ratio (A / B) of sliding surface width A to groove width B: See FIGS. 8 and 9 Sample numbers 18 to 25 and sample numbers 26 to 33 in Table 1 each have a constant number of grooves. (The former is 72, the latter is 36) and the sliding surface width A and groove width B are changed, and the influence of the ratio (A / B) of the sliding surface width A and groove width B is changed. FIG. 8 shows the results of the sample numbers 18 to 25 (72 grooves), and FIG. 9 shows the results of the sample numbers 26 to 33 (36 grooves). The bearings of Sample Nos. 18 and 26 in which A / B is less than 0.5 than these samples have a large sliding surface width A with respect to the groove width B, and sufficient lubricating oil is not supplied to the sliding surface. The static friction coefficient and the dynamic friction coefficient are large. On the other hand, in bearings with sample numbers 19 to 23 (when the number of grooves is 72) and sample numbers 27 to 31 (when the number of grooves is 36) in the range of A / B of 0.5 to 4.05 , Sufficient lubricating oil can be supplied to the moving surface, and both the static friction coefficient and the dynamic friction coefficient are low and stable values. However, in bearings of sample numbers 24, 25, 32, and 33 with A / B exceeding 4.05 , the width A of the sliding surface is larger than the groove width B, and therefore sufficient lubricating oil is applied to the sliding surface. The static friction coefficient and the dynamic friction coefficient are increasing rapidly without being supplied. From these facts, it is understood that A / B needs to be in the range of 0.5 to 4.05 .

(4) Influence of the depth d of the inclined groove: see FIG. 10 The bearings of the sample numbers 20 and 34 to 40 in Table 1 are obtained by examining the influence of the depth of the inclined groove. From these samples, in the bearing of the sample number 34 where the depth of the inclined groove is less than 0.1 mm, the inclined groove is too shallow and sufficient lubricating oil is not stored in the inclined groove. The amount of lubricating oil supplied to the tank becomes insufficient, and both the coefficient of static friction and the coefficient of dynamic friction show large values. On the other hand, in the bearing of the sample number 35 with the depth of the inclined groove of 0.1 mm, the inclined groove has a depth enough to store the lubricating oil, and as a result, the supply amount of the lubricating oil to the sliding surface Is sufficient, and both the coefficient of static friction and the coefficient of dynamic friction are rapidly decreasing. Further, when the depth of the inclined groove is in the range of 0.1 to 3 mm, the static friction coefficient and the dynamic friction coefficient are both low and stable values. However, in the bearing of Sample No. 40 in which the depth of the inclined groove exceeds 3 mm, as the inclined groove becomes too deep, the sliding surface cannot withstand the load and wear occurs. From these facts, it is understood that the depth of the inclined groove is suitably in the range of 0.1 to 3 mm.

[Second Embodiment]
A bearing sample produced by using the same raw material powder as in the first embodiment and similarly molded and sintered has 72 grooves, a sliding surface width A of 2.07 mm, and a groove width B of 1. .42 mm, groove depth of 0.7 mm in common, the inclination angle with respect to the direction orthogonal to the circumferential direction (sliding direction) is changed to the conditions shown in Table 2, and the trapezoidal cross section on the inner peripheral surface by machining And an annular inner circumferential groove, outer circumferential groove and through hole similar to those of the first embodiment were formed. Next, in the same manner as in the first example, machine oil was vacuum impregnated to produce bearings (sample numbers 41 to 53) having the inclination angles of the inclined grooves shown in Table 2. The produced bearing samples 41 to 53 are subjected to a rocking test in the same manner as in the first example, and the values of the obtained static friction coefficient and dynamic friction coefficient are also shown in Table 2. Table 2 also shows the value of the dynamic friction coefficient of the bearing of the sample number 21 of the first embodiment as an example in which the inclined groove has an inclination angle of 20 °.

(5) Influence of the inclination angle of the inclined groove: see FIG. 11 The bearings of the sample numbers 21 and 41 to 53 in Table 2 were examined for the influence of the inclination angle of the inclined groove. From these samples, the bearings (sample numbers 41 and 42) in which the inclination angle of the inclined groove is less than 10 ° and the bearings (sample numbers 51 to 53) in which the inclination angle of the inclined groove exceeds 60 ° are the static friction coefficient and the dynamic friction. Both of the coefficients show high values, but the bearings of the bearings (sample numbers 21, 43-50) with the inclination angle of the inclined grooves of 10 to 60 ° show low values for both the static friction coefficient and the dynamic friction coefficient. Further, in the bearings (sample numbers 21, 44 to 49) in which the inclination angle of the inclined groove is 15 to 50 °, both friction coefficients are smaller, and the bearings (sample number in which the inclination angle of the inclined groove is 20 to 40 °). 21, 45-48) shows the lowest value of both friction coefficients and a stable value. From these facts, it can be seen that the angle of the inclined groove is remarkable in the effect of reducing the static friction coefficient and the dynamic friction coefficient in the range of 10 to 60 °, more preferably 15 to 50 °, and most preferably 20 to 40 °.

[Third embodiment]
A bearing sample produced by using the same raw material powder as in the first embodiment and similarly molded and sintered has 72 grooves, a sliding surface width A of 2.07 mm, and a groove width B of 1. A trapezoidal inclined groove with a common inclination angle of 20 ° with respect to the direction orthogonal to the circumferential direction (sliding direction) is formed on the inner peripheral surface by machining. Two types were produced: one in which the inner circumferential groove, outer circumferential groove and through hole were formed by machining, as in the first example, and one in which the inner circumferential groove, outer circumferential groove and through hole were not formed. Next, as in the first example, both were vacuum impregnated with machine oil to prepare a bearing sample having an inner circumferential groove, an outer circumferential groove and a through hole, and a bearing sample not having these. The produced two types of bearing samples were continuously subjected to a rocking test in the same manner as in the first example, and the operation time was compared with the time when the static friction coefficient exceeded 0.15.

  As a result, a bearing sample having an inner circumferential groove, an outer circumferential groove and a through-hole does not reach the service life even if it is continuously operated for a time longer than the time that the bearing sample without these reaches the service life. It was confirmed that a bearing sample having a groove and a through-hole has a life that is twice or more that of a bearing sample not having these.

  The slide bearing of the present invention is relatively large and suitable for applications in which a surface pressure of 20 MPa or more acts and the swing speed is relatively slow and swings. Specifically, for example, joint bearings for construction machines such as bulltozers and power shovels, joint bearings for article transfer robots, and the like can be given.

It is a perspective view of the bearing of one Embodiment of this invention. FIG. 2 is a side view and a side sectional view of the bearing shown in FIG. 1. It is an expanded view which shows the internal peripheral surface of the bearing shown in FIG. It is sectional drawing of the inclined groove formation part of the state which inserted the axis | shaft in the bearing. It is sectional drawing of the inner periphery groove | channel and the outer periphery groove | channel formation part of the state which inserted the axis | shaft in the same bearing. It is a test result of the Example which clarifies the influence of the width A of a sliding surface, Comprising: It is a diagram which shows the relationship of the width A, a static friction coefficient, and a dynamic friction coefficient. It is a test result of the Example which clarifies the influence of the groove width B of an inclined groove | channel, Comprising: It is a diagram which shows the relationship between the groove width B, a static friction coefficient, and a dynamic friction coefficient. It is a test result of the example which clarifies the influence of the ratio (A / B) of the width A of the sliding surface and the groove width B when the number of inclined grooves is 72, and A / B and static friction It is a diagram which shows an example of the relationship between a coefficient and a dynamic friction coefficient. It is a test result of the example which clarifies the influence of the ratio (A / B) of the width A of the sliding surface and the groove width B when the number of inclined grooves is 36, and A / B and static friction It is a diagram which shows an example of the relationship between a coefficient and a dynamic friction coefficient. It is a test result of the Example which clarifies the influence of the depth d of an inclined groove | channel, Comprising: It is a diagram which shows the relationship between the depth d of the groove | channel, a static friction coefficient, and a dynamic friction coefficient. It is a test result of the Example which clarifies the influence of the inclination angle of an inclination groove | channel, Comprising: It is a diagram which shows the relationship between the inclination angle, a static friction coefficient, and a dynamic friction coefficient.

Explanation of symbols

1 ... Bearing (Slide bearing)
DESCRIPTION OF SYMBOLS 10 ... Inner peripheral surface 11 ... Shaft hole 12 ... Inclined groove 14 ... Sliding surface 15 ... Inner peripheral groove (annular groove)
16 ... outer peripheral groove (annular groove)
17 ... Through hole 20 ... Axis A ... Circumferential width of sliding surface B ... Circumferential groove width of inclined groove R ... Circumferential direction S ... Direction orthogonal to circumferential direction

Claims (3)

A plurality of linear inclined grooves extending in a direction crossing the circumferential direction are formed at intervals in the circumferential direction on an inner circumferential surface on which the shaft inserted into the shaft hole is rotatably supported. , A sliding bearing in which lubricating oil is supplied to these inclined grooves,
The inclined groove is formed under the following conditions (A) to (D),
It is inclined in the range of 15 ° to 50 ° with respect (A) direction perpendicular to the circumferential direction.
(B) The circumferential groove width B is 1.19 to 5 mm.
(C) The width A in the circumferential direction of the sliding surface, which is the surface of the crest between adjacent inclined grooves, is 1 to 7 mm.
(D) Ratio A / B of the width A of the sliding surface of the peak portion and the groove width B is 0.5 to 4.05 .
Further, an annular groove is formed in at least a pair of states on the inner periphery and outer periphery of the sliding bearing, and the annular groove formed on the inner periphery communicates with the inclined groove,
At least one through-hole for communicating the pair of annular grooves with each other is formed.   The slide bearing according to claim 1, wherein a depth d of the inclined groove is 0.1 to 3 mm.   The sliding bearing according to claim 1, wherein the bearing is made of a sintered alloy.

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