JP2020112209A - Roller bearing - Google Patents

Abstract

To suppress NV (noise and vibration) of a roller bearing having an inner ring composed of a plurality of split members.SOLUTION: A roller bearing 1 includes an inner ring 3 provided with: a pair of flange portions 32 disposed along a circumferential direction at both end portions in an axial direction, and having a raceway surface 3b on a belt-like outer peripheral surface 3a between the pair of flange portions 32; a plurality of rollers 4 respectively having a columnar main body portion 41 rolling on the raceway surface 3b, and a pair of shaft portions 42 projected from both end portions of the main body portion 41; and a retainer 5 for retaining the plurality of rollers 4. The inner ring 3 is composed of a first inner ring member 3A, and a second inner ring member 3B disposed in parallel with each other in the circumferential direction. First joint portions of the first inner ring member 3A and the second inner ring member 3B on the outer peripheral surfaces 32a of the pair of flange portions 32 are disposed on a position deviated in a circumferential direction, from a second joint portion 302 of the first inner ring member 3A and the second inner ring member 3B on a belt-like outer peripheral surface 3a, and when the main body portions 41 of the rollers 4 are positioned beyond the second joint portions 302, the pair of shaft portions 42 are supported by the pair of flange portions 32, and the main body portions 41 are separated from the belt-like outer peripheral surface 3a.SELECTED DRAWING: Figure 6

Description

The present invention relates to a roller bearing.

BACKGROUND ART Conventionally, a crankshaft of an automobile engine is supported by an engine block via a bearing. As this bearing, a slide bearing is generally used, but in order to reduce the rotational resistance of the crankshaft and improve the fuel efficiency, a roller with multiple rolling elements arranged around the inner ring is used. It has been proposed to use bearings.

The crankshaft includes an assembly type in which a plurality of parts such as a crank arm, a crank journal, and a crankpin are assembled, and an integral type in which the whole is integrally formed by casting. In the integrated crankshaft, since the cylindrical inner ring cannot be assembled in the crank journal from the axial direction, a split inner ring is used as described in Patent Document 1, for example.

JP, 2010-11710, A

When a rotating member such as a crankshaft is supported by a roller bearing having two split inner rings, noise and vibration may occur when the rollers cross over the joints of the inner rings. Such noise and vibration (hereinafter referred to as “NV”) become remarkable especially when the rotation speed of the rotating member becomes high.

Therefore, an object of the present invention is to suppress NV of a roller bearing having an inner ring composed of a plurality of divided members.

In order to achieve the above-mentioned object, the present invention is provided with a pair of convex portions projecting in the radial direction at both ends in the axial direction along the circumferential direction, and a raceway surface on the strip-shaped outer peripheral surface between the pair of convex portions. A plurality of rollers having an inner ring in which the inner ring is formed, a cylindrical main body that rolls on the raceway surface, and a pair of shafts that project from both ends of the main body, and a retainer that holds the plurality of rollers. And the inner ring is composed of a plurality of division members arranged side by side in the circumferential direction, and the first joint of the plurality of division members on the outer peripheral surfaces of the pair of protrusions. A portion is provided at a position circumferentially offset from the second joint portion of the plurality of split members on the strip-shaped outer peripheral surface, and when the main body portion of the roller crosses the second joint portion, the pair of A roller bearing in which a shaft portion is supported by the pair of convex portions and the main body portion is separated from the belt-shaped outer peripheral surface.

According to the present invention, NV of a roller bearing having an inner ring composed of a plurality of divided members can be suppressed.

It is a sectional view showing an example of composition of an engine containing a crankshaft supported by a cylinder block by a roller bearing concerning an embodiment of the invention. It is a perspective view showing a crankshaft with a lower end part of a cylinder block, a plurality of crank caps, and the like. (A) is sectional drawing which shows a roller bearing and its periphery by a cross section perpendicular|vertical to an axial direction, (b) is a side view which shows a roller bearing. (A), (b) is explanatory drawing which shows the state before and after attachment to the crank journal of the inner ring of a roller bearing. It is a perspective view showing the 1st inner ring member which constitutes the inner ring of a roller bearing. (A) is explanatory drawing which shows a part of inner ring with a roller. (B) is a sectional view of the inner ring shown together with the rollers facing the non-raceway surface of the belt-shaped outer peripheral surface of the inner ring. (C) is a sectional view of the inner ring shown together with the rollers facing the raceway surface of the belt-shaped outer peripheral surface of the inner ring.

[Embodiment]
An embodiment of the present invention will be described with reference to FIGS. Note that the embodiments described below are shown as preferred specific examples for carrying out the present invention, and some parts specifically exemplify various technically preferable technical matters. The technical scope of the present invention is not limited to this specific embodiment.

(Engine configuration)
FIG. 1 is a cross-sectional view showing a configuration example of an engine including a crankshaft supported by a cylinder block by a roller bearing according to an embodiment of the present invention. FIG. 2 is a perspective view showing a crankshaft together with a lower end portion of a cylinder block, a plurality of crank caps, and the like.

The engine 10 is used as a drive source for an automobile, and includes a cylinder block 11, a cylinder head 12 mounted above the cylinder block 11, an oil pan 13 mounted below the cylinder block 11, and a crank serving as a rotating member. And a shaft.

A cam shaft (not shown) is housed in the cylinder head 12. In the cylinder block 11, a plurality of cylinders 110 accommodating the pistons 14 are partitioned by partition walls 111, and the pistons 14 are connected to the crankshaft 2 by connecting rods (connecting rods) 15. The crankshaft 2 receives the combustion pressure due to the explosion of the air-fuel mixture supplied to the cylinder 110 via the piston 14 and the connecting rod 15, is supported between the cylinder block 11 and the oil pan 13, and rotates about the rotation axis O. To do. Hereinafter, a direction parallel to the rotation axis O will be referred to as an axial direction, and a direction perpendicular to the rotation axis O will be referred to as a radial direction.

The crankshaft 2 includes a plurality of crank arms 21, a balance weight 22 provided on some of the plurality of crank arms 21, a crank journal 23 having a rotation axis O as a central axis, and a rotation axis O. It has a crank pin 24 which is eccentric with respect to the cylinder block 11, and rotates in a fixed direction with respect to the cylinder block 11. A crank pulley 16 around which a belt for driving auxiliary machinery is wound is attached to one end of the crankshaft 2. Each part of the crankshaft 2 is integrally formed by casting, and the outer peripheral surfaces of the crank journal 23 and the crankpin 24 are ground.

In the present embodiment, the crankshaft 2 has eight crank arms 21, five crank journals 23, and four crank pins 24. Of the five crank journals 23, the two crank journals 23 at both ends are supported between the side wall 112 of the cylinder block 11 and the edge wall 131 of the oil pan 13. The other three crank journals 23 are supported between the partition wall 111 of the cylinder block 11 and the plurality of crank caps 17 fixed to the partition wall 111. The crank cap 17 is fixed to the lower end of the partition wall 111 by a bolt 18.

As shown in FIG. 2, semicircular notches 111a and 112a are formed in the lower ends of the partition wall 111 and the side wall 112 of the cylinder block 11 when viewed in the axial direction. The crank cap 17 is formed with a semicircular cutout 17 a that is combined with the cutout 111 a of the partition wall 111. The notch 111a of the partition wall 111 and the notch 17a of the crank cap 17 are combined into a circular shape. Next, the structure of the roller bearing 1 of the present embodiment, which supports the crank journal 23 between the partition wall 111 of the cylinder block 11 and the crank cap 17, will be described.

(Bearing structure of crankshaft)
3A is a cross-sectional view showing the roller bearing 1 and its peripheral portion in a cross section perpendicular to the axial direction, and FIG. 3B is a side view showing the roller bearing 1. 4A and 4B are explanatory views showing states before and after mounting the inner ring 3 of the roller bearing 1 on the crank journal 23. FIG. 5 is a perspective view showing a first inner ring member 3A forming the inner ring 3 of the roller bearing 1. FIG. 6A is an explanatory view showing a part of the inner ring 3 together with the rollers 4. FIG. 6B is a sectional view of the inner ring 3 shown together with the rollers 4 facing the non-raceway surface 3c of the belt-shaped outer peripheral surface 3a of the inner ring 3. FIG. 6C is a cross-sectional view of the inner ring 3 shown together with the rollers 4 facing the raceway surface 3b of the belt-shaped outer peripheral surface 3a of the inner ring 3.

The roller bearing 1 includes an inner ring 3 mounted so as to surround an outer peripheral surface 23a of a crank journal 23, a plurality of rollers 4 arranged on the outer periphery of the inner ring 3, a cage 5 for holding the plurality of rollers 4, and a partition wall. 111 and the outer ring 6 attached to the notches 17 a and 111 a of the crank cap 17.

The outer ring 6 has a split structure and includes a first outer ring member 6A attached to the cutout 111a of the partition wall 111 and a second outer ring member 6B attached to the cutout 17a of the crank cap 17. In the present embodiment, the roller bearing 1 has 12 rollers 4 as rolling elements. However, the number of rollers 4 can be appropriately selected according to the outer diameter of the crank journal 23 and the like.

When the crankshaft 2 rotates with respect to the cylinder block 11, the plurality of rollers 4 revolve around the rotation axis O together with the retainer 5 while rotating about the center axis thereof. In FIGS. 3A and 6A, an arrow A indicates the relative revolving direction of the plurality of rollers 4 with respect to the inner ring 3 when the crankshaft 2 rotates with respect to the cylinder block 11.

The inner ring 3 has a split structure and is formed in a ring shape as a whole. The inner ring 3 has a cylindrical base portion 31 having a belt-shaped outer peripheral surface 3a extending over the entire circumference in the circumferential direction, and a pair of convex portions projecting radially outward from the belt-shaped outer peripheral surface 3a at both ends in the axial direction. And a pair of locking projections 33 for suppressing relative rotation with respect to the crank journal 23. The collar portion 32 extends over the entire circumference of the inner ring 3 in the circumferential direction, and a strip-shaped outer peripheral surface 3 a is formed between the pair of collar portions 32.

As shown in FIGS. 6A and 6B, the roller 4 has a columnar main body portion 41 and a pair of shaft portions 42 protruding from both axial end portions of the main body portion 41. The outer diameter of the shaft portion 42 is formed smaller than the outer diameter of the main body portion 41. In the present embodiment, the shaft portion 42 has a tapered shape, and the outer diameter of the shaft portion 42 gradually becomes smaller at a position further away from the main body portion 41 in the axial direction. The shaft portion 42 may have a columnar shape having an outer diameter smaller than that of the main body portion 41. The body portion 41 is arranged between the pair of flange portions 32 so as to face the strip-shaped outer peripheral surface 3 a of the inner ring 3. The shaft portion 42 is arranged such that the tip portion thereof projects outward in the axial direction from the pair of flange portions 32.

The cage 5 has a cylindrical cylindrical portion 51 arranged radially outward of the pair of collar portions 32 of the inner ring 3, and extends radially inward from both axial end portions of the cylindrical portion 51. The side plate portion 52 is provided so as to sandwich the pair of collar portions 32 in the axial direction. The cylindrical portion 51 is formed with a plurality of (the same number as the rollers 4) window portions 510 penetrating between the inner and outer peripheral surfaces thereof. A holding hole 520 for holding the shaft portion 42 of the roller 4 is formed in the side plate portion 52. In the plurality of rollers 4, a part of the main body portion 41 protrudes outward in the radial direction of the cage 5 from the window portion 510 of the cylindrical portion 51, and the pair of shaft portions 42 are held in the holding holes 520 of the side plate portion 52. ..

In addition, the cylindrical portion 51 of the cage 5 is arranged on the outer peripheral side (outer ring 6 side) with respect to the center of the plurality of rollers 4, and a part of the outer peripheral surface 41 a of the main body portion 41 of the roller 4 extends from the window 510 to the outer ring 6. Of the track surface 6a. The side plate portion 52 has a cut 521 extending from the radially inner end to the holding hole 520. When the roller 4 is attached to the cage 5, the side plate portion 52 is elastically deformed and the tip of the shaft portion 42 is introduced into the holding hole 520 through the notch 521.

The cage 5 is a combination of a first cage member 5A that holds six rollers 4 out of the 12 rollers 4 and a second cage member 5B that holds the remaining six rollers 4. The structure is divided into two parts, and is formed in a ring shape as a whole. The first cage member 5A and the second cage member 5B are made of, for example, resin molded by injection molding, and the cylindrical portion 51 and the side plate portion 52 are integrally molded.

The inner ring 3 is composed of a plurality of divided members arranged side by side in the circumferential direction. In the present embodiment, as shown in FIGS. 4A and 4B, the inner ring 3 is composed of a first inner ring member 3A and a second inner ring member 3B. Each of the first inner ring member 3A and the second inner ring member 3B corresponds to the above-mentioned divided member. The first inner ring member 3A and the second inner ring member 3B are formed in the same shape as each other, and end surfaces of flat surfaces 30a and 30b inclined with respect to the circumferential direction of the inner ring 3 are arranged to face each other. The first inner ring member 3A and the second inner ring member 3B are made of, for example, bearing steel such as SUJ2 or low carbon steel.

Of the pair of locking projections 33 of the inner ring 3, one locking projection 33 is provided on the first inner ring member 3A, and the other locking projection 33 is provided on the second inner ring member 3B. The respective locking protrusions 33 are fitted into the concave grooves 230 formed on the outer peripheral surface of the crank journal 23, and are locked to the crank journal 23. As a result, the relative rotation of the inner ring 3 with respect to the crank journal 23 is restricted. The locking means is not limited to this embodiment. That is, the first inner ring member 3A and the second inner ring member 3B may be prevented from rotating with respect to the crank journal 23. Specifically, the first inner ring member 3A and the second inner ring member 3B may be prevented from rotating with respect to the crank journal 23 by a key groove, a press fit in the width direction, or the like.

The planes 30a and 30b of the first inner ring member 3A and the second inner ring member 3B are relative to the radial direction of the inner ring 3 when the inner ring 3 is viewed from the axial direction as shown in FIGS. 4(a) and 4(b). It is an inclined straight line. Therefore, the first joint portion 301 of the first inner ring member 3A and the second inner ring member 3B on the outer peripheral surfaces 32a of the pair of flange portions 32 with which the shaft portion 42 of the roller 4 contacts is the first inner ring member on the belt-shaped outer peripheral surface 3a. 3A and the second joint portion 302 of the second inner ring member 3B and the inner ring 3 are provided at positions displaced from each other in the circumferential direction.

Further, the planes 30a and 30b are inclined so as to approach the outer peripheral surface 32a of the collar portion 32 toward the rear side in the direction of relative rotation of the plurality of rollers 4 with respect to the inner ring 3 as indicated by the arrow A. Therefore, in the present embodiment, the first seam portion 301 is located on the rear side of the second seam portion 302 in the revolving direction. The first joint portion 301 is not limited to this, and the first joint portion 301 may be located on the front side of the second joint portion 302 in the above-described revolution direction. That is, the inclinations of the planes 30a and 30b with respect to the radial direction of the inner ring 3 may be opposite to those shown in FIGS. 4(a) and 4(b).

A part of the belt-shaped outer peripheral surface 3a in the circumferential direction is formed as a raceway surface 3b on which the main body portion 41 of the roller 4 rolls. The other part of the belt-shaped outer peripheral surface 3a in the circumferential direction is formed as a non-raceway surface 3c on which the main body portion 41 of the roller 4 does not roll. As shown in FIG. 4B, the raceway surface 3b has an arc shape with a constant distance R _{1 from the} rotation axis O. This distance R ₁ is the raceway diameter of the raceway surface 3b. The belt-shaped outer peripheral surface 3a has non-raceway surfaces 3c at two positions symmetrical with respect to the rotation axis O, and in the circumferential direction of the inner ring 3, a raceway surface 3b is formed between the two non-raceway surfaces 3c. ing.

The strip-shaped outer peripheral surface 3a is recessed radially inward from the raceway diameter of the raceway surface 3b over a predetermined circumferential range including the second joint portion 302. In the present embodiment, the portion recessed inward in the radial direction is the non-track surface 3c. The non-raceway surface 3c is flat as shown in FIG. 5, and is formed over the first inner ring member 3A and the second inner ring member 3B. As shown in FIGS. 4A and 4B, when the inner ring 3 is viewed from the axial direction, the non-raceway surface 3c is perpendicular to the straight line connecting the second joint 302 and the rotation axis O. It is a straight line. The second seam portion 302 is located at the center of the non-raceway surface 3c in the circumferential direction of the inner ring 3. As shown in FIG. 4B, when the distance between the second joint portion 302 and the rotation axis O on the strip-shaped outer peripheral surface 3a is R ₂ , this distance R ₂ is the raceway diameter of the raceway surface 3b. It is shorter than the distance R ₁ .

The first seam portion 301 is provided at a position of the belt-shaped outer peripheral surface 3a excluding a portion that is radially outside the non-track surface 3c. In FIG. 6A, a range E of a portion that is on the radially outer side of the non-track surface 3c is illustrated. Further, in FIG. 6A, the distance between the second seam portion 302 in the radial direction of the inner ring 3 and the outer peripheral surface 32a of the collar portion 32 in contact with the shaft portion 42 (the collar portion 32 from the non-raceway surface 3c). Is represented by a distance H ₁ and corresponds to the distance between the raceway surface 3b and the outer peripheral surface 32a of the collar portion 32 in the radial direction of the inner ring 3 (corresponding to the height of the collar portion 32 from the raceway surface 3b). Yes) is indicated by the distance H ₂ . Further, in FIG. 6 (a), represents the distance between the outer peripheral surface 41a of the outer peripheral surface 42a and the main body portion 41 of the shaft portion 42 in contact with the outer peripheral surface 32a of the collar portion 32 as a distance _{R 3.}

There is a relationship of H ₁ >R ₃ >H ₂ between these distances H ₁ , H ₂ and R ₃ . That is, the distance R ₃ between the outer peripheral surface 41a of the outer peripheral surface 42a and the main body portion 41 of the shaft portion 42 is greater than the height of the flange portion 32 from the raceway surface 3b, the flange portion 32 from the non-raceway surface 3c Smaller than height.

In the present embodiment, the outer peripheral surface 32a of the collar portion 32 has a constant radius R (see FIG. 4(b)) centered on the rotation axis O over the entire circumference. However, the outer diameter of the collar portion 32 may be smaller than the radius R of the portion of the shaft portion 42 that is in contact with the outer peripheral surface 42a of the shaft portion 42 in the portion that does not contact the outer peripheral surface 42a of the shaft portion 42. Alternatively, the collar portion 32 may not be formed in at least a part of the portion other than the range E.

With the above configuration, when the roller 4 revolves around the inner ring 3 in the direction of the arrow A while the body portion 41 crosses over the second joint portion 302, as shown in FIG. The portion 42 is supported by the pair of collar portions 32, and the main body portion 41 is separated from the strip-shaped outer peripheral surface 3a (non-raceway surface 3c). That is, the main body portion 41 of the roller 4 passes through the outer periphery of the second joint portion 302 without contacting the second joint portion 302. Further, when the roller 4 crosses the first joint portion 301, as shown in FIG. 6C, the outer peripheral surface 41a of the main body portion 41 contacts the raceway surface 3b, and the outer peripheral surface 42a of the shaft portion 42 has the collar portion 32. Away from the outer peripheral surface 32a. Thereby, the shaft portion 42 passes through the outer circumference of the first joint portion 301 without contacting the first joint portion 301.

In this way, the main body portion 41 and the shaft portion 42 of the roller 4 revolve with respect to the inner ring 3 without contacting any of the first joint portion 301 and the second joint portion 302. Therefore, it is possible to suppress the generation of NV while using the split inner ring 3.

The mounting position of the inner ring 3 in the circumferential direction of the outer peripheral surface 23a of the crank journal 23 is in a range outside the angular position where the maximum load load that the crank journal 23 receives from the connecting rod 15 via the crank pin 24 and the crank arm 21 acts. It is desirable to set so that the non-orbital surface 3c is located at. At the position corresponding to the non-raceway surface 3c, the main body portion 41 of the roller 4 is separated from the belt-shaped outer peripheral surface 3a, so that the maximum value of the load that the roller 4 can receive is higher than that when the main body portion 41 is in contact with the raceway surface 3b. Is also smaller.

That is, there is a predetermined relationship between the rotational position of the crankshaft 2 with respect to the cylinder block 11 and the timing at which the air-fuel mixture supplied to the cylinder 110 is ignited to generate combustion pressure. The angle of the maximum load acting on the crank journal 23 of the crankshaft 2 can be defined by the above, and by mounting the inner ring 3 on the crank journal 23 so that the non-raceway surface 3c is located in a range outside this angle, The maximum load can be received by the raceway surface 3b of the inner ring 3.

(Appendix)
Although the present invention has been described above based on the embodiments, these embodiments do not limit the invention according to the claims. Further, it should be noted that not all combinations of the features described in the embodiments are essential to the means for solving the problems of the invention.

Further, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention. For example, in the above embodiment, the case where the roller bearing 1 is arranged on the outer periphery of the crank journal 23 of the crankshaft 2 has been described, but the present invention is not limited to this, and the roller bearing 1 is arranged between the crank pin 24 and the connecting rod 15. You may. Further, the roller bearing 1 may be used to support the rotating members other than the crankshaft 2.

Further, in the above embodiment, the case where the inner ring 3 is composed of two split members (the first inner ring member 3A and the second inner ring member 3B) has been described, but the inner ring 3 is composed of three or more split members. Good. Furthermore, although the case where the roller bearing 1 has the outer ring 6 has been described in the above embodiment, the outer ring 6 may be omitted.

DESCRIPTION OF SYMBOLS 1... Roller bearing 3... Inner ring 301... 1st joint part 302... 2nd joint part 30a, 30b... Flat surface 3a... Strip-shaped outer peripheral surface 3A... 1st inner ring member (divided member) 3b... Raceway surface 3B... 2nd inner ring member ( Dividing member 3c... Non-raceway surface 4... Roller 41... Main body 42... Shaft 5... Retainer 51... Cylindrical portion 510... Window 52... Side plate 520... Retaining hole

Further, the planes 30a and 30b are inclined so as to approach the outer peripheral surface 32a of the collar portion 32 toward the rear side in the direction of relative rotation of the plurality of rollers 4 with respect to the inner ring 3 as indicated by the arrow A. Therefore, in the present embodiment, the first seam portion 301 is located on the front side of the second seam portion 302 in the revolving direction. However, the present invention is not limited to this, and the first joint portion 301 may be located on the rear side of the second joint portion 302 in the above-described revolution direction. That is, the inclinations of the planes 30a and 30b with respect to the radial direction of the inner ring 3 may be opposite to those shown in FIGS. 4(a) and 4(b).

Claims (5)

A pair of convex portions radially outwardly projecting at both ends in the axial direction are provided along the circumferential direction, and an inner ring having a raceway surface formed on a belt-shaped outer peripheral surface between the pair of convex portions,
A columnar main body portion rolling on the raceway surface, and a plurality of rollers having a pair of shaft portions protruding from both end portions of the main body portion,
A roller bearing comprising: a retainer for retaining the plurality of rollers,
The inner ring is composed of a plurality of divided members arranged side by side in the circumferential direction,
The first joints of the plurality of dividing members on the outer peripheral surfaces of the pair of protrusions are provided at positions displaced in the circumferential direction from the second joints of the plurality of dividing members on the strip-shaped outer peripheral surface,
When the body portion of the roller crosses the second seam portion, the pair of shaft portions are supported by the pair of convex portions to separate the body portion from the belt-shaped outer peripheral surface.
Roller bearing. The strip-shaped outer peripheral surface is recessed inward in the radial direction with respect to a raceway diameter of the raceway surface over a predetermined range in the circumferential direction including the second seam portion.
The roller bearing according to claim 1. The first seam portion is provided at a position on the strip-shaped outer peripheral surface excluding a portion corresponding to a radial outside of a predetermined range in the circumferential direction.
The roller bearing according to claim 2. The plurality of split members are formed in the same shape as each other, and end surfaces formed of flat surfaces inclined with respect to the circumferential direction of the inner ring are arranged to face each other.
The roller bearing according to any one of claims 1 to 3. The cage has a cylindrical cylindrical portion arranged radially outward of the pair of convex portions of the inner ring, and extends radially inward from both axial end portions of the cylindrical portion. And a side plate portion provided so as to sandwich the pair of convex portions,
In the plurality of rollers, a part of the main body portion projects radially outward from a window portion formed in the cylindrical portion, and the shaft portion is held in a holding hole formed in the side plate portion.
The roller bearing according to any one of claims 1 to 4.

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