JP2008185051A - Trust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an edge load in a thrust roller bearing even when the outer diameter of race is made small. <P>SOLUTION: In a thrust roller bearing 200 attached to a swash plate compressor 100, a plane portion 24 profiled in convex with which a roller bearing 21 contacts and each of crowning portions 23 in which the inner peripheral surface 25 and outer peripheral surface 26 of each of races 18, 19 continue in a loose curved profile are formed in the inner peripheral edge portion and outer peripheral edge portion of truck surfaces 18a, 19a of its inner and outer races 18, 19. Furthermore, when each of races 18, 19 is bent by an axially biased pre-load F, the edge load is prevented from being generated in such a way that a peripheral portion of edge surface of the roller bearing 21 may not directly contact with a plane portion 24 of each of races 18, 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thrust roller bearing.

  The swash plate of the swash plate type compressor is rotatably supported by a thrust roller bearing. A predetermined preload (a load in the axial direction) is applied to the thrust roller bearing in order to suppress the occurrence of vibrations due to mounting errors and piston load fluctuations. Thereby, the race of the thrust roller bearing is bent. Then, a large stress (edge load) acts on the contact portion between the edge of the roller (cylindrical roller) and the raceway surface of the race, and the raceway surface of the race may be peeled off (flaking). The life of the roller bearing will be shortened. In order to prevent this problem, in a thrust roller bearing of a swash plate type compressor, a technique is disclosed in which the influence of race bending is absorbed by crowning the end edge of the roller (see Patent Document 1). ).

In the case of a conventional thrust roller bearing, the raceway surface is relatively larger than the overall length of the roller. In this case, the rollers are supported on the main surface of the race at a substantially intermediate position in the radial direction between the outer peripheral edge portion and the inner peripheral edge portion. Occurrence can be prevented. However, with the recent demand for lighter and more compact swash plate compressors, it is necessary to reduce the outer diameter of the thrust roller bearing race. Then, the influence of the bending of the race directly affects the roller (particularly, the edge portion of the roller), and it may not be possible to avoid the occurrence of edge load only by crowning the roller.
Japanese Patent Laid-Open No. 9-14131

  In view of the above-described problems, the present invention has an object to prevent an edge load from occurring even if the outer diameter of a race is reduced in a thrust roller bearing.

Means for Solving the Problems and Effects of the Invention

The thrust roller bearing according to the present invention for achieving the above-described object is
An annular first race in which the first raceway surface of the rolling element is formed on the main surface;
The second raceway surface of the rolling element is formed in an annular shape formed on the main surface, and the first raceway surface and the second raceway surface are arranged so as to face each other in the axial direction, and the first race A second race that rotates relative to the first race around an axis in a state where the rolling member is interposed between the rolling race and the preload is biased toward the first race via the rolling member. With
A crowning portion that is curved in a convex shape toward the arrangement space of the rolling elements is formed in each of the inner peripheral edge portion and the outer peripheral edge portion of the first and second raceway surfaces. .
Specifically, the rolling element is a cylindrical roller,
In the first and second raceway surfaces, a flat surface portion in contact with the cylindrical roller is formed at a radial intermediate position from the inner peripheral edge portion to the outer peripheral edge portion,
The crowning portion may be formed in a form following an outer peripheral surface or an inner peripheral surface of the race from an end edge in a radial direction of the flat portion.

  The thrust roller bearing according to the present invention is configured as described above. The first and second races are bent by the preload, and the end edge of the rolling element presses the raceway surface of the race to try to apply an edge load. However, the edge load is directly applied to the raceway surface of each race by the crowning portion formed continuously with the inner peripheral surface or the outer peripheral surface of the raceway surface and the outer peripheral surface of each race and the convex shape. Acting is avoided. As a result, each race is prevented from being damaged by the edge load, and the life of the thrust roller bearing is extended.

  And the length of the crowning portion in the radial direction is formed to be longer than the length in the axial direction. Specifically, the length of the crowning portion in the axial direction is more than 100 μm and less than 400 μm. It is desirable that

  By making the length of the crowning portion in the radial direction longer than the length in the axial direction, the curvature of the radial direction portion in the crowning portion becomes larger than the curvature of the axial direction portion. As a result, when each race is bent, the gap between the rolling elements (cylindrical rollers) and the raceway surface of each race can be gradually reduced, and the advantage that the occurrence of edge load can be prevented. The operation of the thrust roller bearing can be stabilized without loss.

  In the first and second races, the crowning portion is formed only on one main surface of the main surfaces on which the raceway surface is formed, and the other main surface is a flat surface. Can do.

  By forming the crowning portion only on one main surface of each race, the manufacturing process can be simplified.

Further, the first race is biased partially toward the second race only on the outer peripheral edge thereof on the main surface opposite to the main surface on which the first raceway surface is formed,
The second race is such that only the inner peripheral edge thereof is partially biased toward the first race on the main surface opposite to the main surface on which the second raceway surface is formed. can do.

  The preload can be effectively applied to each race.

The thrust roller bearing is used in a swash plate type compressor in which a piston is reciprocated in an axial direction in a cylinder by a rotating operation of a swash plate fixed to a rotating shaft.
The first race may be urged by the swash plate, and the second race may be urged by a cylinder.

  Since the life of the thrust roller bearing is extended, the life of the swash plate compressor using the thrust roller bearing can be extended and the reliability thereof can be increased.

  Furthermore, a roller-side crowning portion having a shape in which the distance from the rotation axis of the cylindrical roller decreases toward the end surface of the outer peripheral surface of the cylindrical roller can be formed.

  Since the roller side crowning portion is provided not only in the first and second races but also in the cylindrical roller, it is possible to reliably avoid the edge load from acting on each race.

  The first and second races are formed by punching a metal plate, and a dripping portion formed in accordance with the punching processing is used as the crowning portion, and a burr portion formed on the opposite side is formed. It can be formed by polishing.

  Since the first and second races are formed by punching a metal plate, the cost can be reduced. Moreover, since the dripping portion generated in the punching process can be directly used as the crowning portion, the number of polishing processes after the punching process can be reduced.

  Examples of the present invention will be described. 1 is a front sectional view of the swash plate compressor 100, FIG. 2 is a sectional view taken along line XX in FIG. 1, and FIG. 3 is an enlarged view of a portion A in FIG.

  In the present specification, a thrust roller bearing 200 used in the swash plate compressor 100 will be described. First, the swash plate compressor 100 will be described. As shown in FIG. 1, a piston 3 is inserted into a space V formed by two cylinders 1 and 2 connected in series along the axial direction, and a rotating shaft 4 is disposed at the axial center thereof. Is arranged. The piston 3 can move in the space V along the axial direction (the direction of the axis 4a of the rotating shaft 4). Side covers 6 and 7 are attached to the end portions of the cylinders 1 and 2 through the cylinder heads 5. The rotating shaft 4 is rotatable by the radial roller bearings 8 and 9 mounted on the cylinders 1 and 2 and the side cover 7 on the side from which the rotating shaft 4 protrudes.

  As shown in FIGS. 1 and 2, the rotating shaft 4 is inserted into the axial center portion of each cylinder 1, and the boss portions 11 and 12 for mounting the radial roller bearings 8 are concentric. Is provided. Between each boss | hub part 11 and 12, the diagonal disk-shaped swash plate 13 is attached via the thrust roller bearing 200, respectively. For this reason, the length in the axial direction of each boss portion 11, 12 is shorter than the total length of each cylinder 1, 2 by the thickness of the shaft portion 14 of the swash plate 13 and the bearing width of each thrust roller bearing 200. It has become. In addition, convex portions 11a and 12a project in an annular shape on the inner peripheral edge portions of the end surface portions of the boss portions 11 and 12 of the cylinders 1 and 2, and the outer end surfaces of both end surfaces of the shaft portion 14 of the swash plate 11. Each convex part 14a protrudes in the periphery at the periphery.

  The swash plate 13 is attached to the rotating shaft 4 and is rotatable together with the rotating shaft 4. Further, the swash plate 13 is connected to the piston 3 via shoes 16 and balls 17 attached to both surfaces of the peripheral portion of the main body portion 15. When the rotating shaft 4 is rotated in a predetermined direction by a driving means (not shown), the swash plate 13 is also rotated in the same direction. Thereby, the piston 3 is reciprocated in the direction of the arrow P.

  The thrust roller bearing 200 of the present embodiment will be described in further detail. Since the configuration of the thrust roller bearings arranged on both sides of the swash plate 13 is exactly the same, only the thrust roller bearing 200 on one side (the A portion on the left side in the drawing of FIG. 1) will be described in this specification. As shown in FIGS. 3 and 4, in the thrust roller bearing 200 of the present embodiment, the main surfaces S <b> 1 on the side where the raceway surfaces 18 a and 19 a are provided are opposed to each other at a predetermined interval in the axial direction. The inner and outer races 18 and 19, a plurality of cylindrical rollers 21 disposed between the main surfaces S1 of the races 18 and 19, and a cage 22 for holding the cylindrical rollers 21 in a rollable manner. ing. The length La of the raceway surfaces 18a and 19a on the main surface S1 of each race 18 and 19 is slightly longer than the total length Lb of the cylindrical rollers 21. In the case of the thrust roller bearing 200 of the present embodiment, the main surface S1 and the raceway surfaces 18a and 19a are substantially the same concept.

  Crowning is applied to the inner peripheral edge and the outer peripheral edge on the main surface S1 side of the inner and outer races 18, 19, respectively, and each crowning portion 23 is provided. The main surface S2 side is a flat surface. In the case of the thrust roller bearing 200 of the present embodiment, crowning portions 23 that are curved outwardly are provided at the inner peripheral edge and the outer peripheral edge of each of the races 18 and 19. A flat surface portion 24 is formed between the crowning portions 23 on the raceway surfaces 18a and 19a. Each crowning portion 23 flat portion 24 and each crowning portion 23 and the inner peripheral surface 25 or outer peripheral surface 26 of each race 18, 19 are continuous in a gently curved shape.

  The length (radial length L2) of the radial direction portion of each crowning portion 23 in the inner and outer races 18 and 19 is longer than the length of the axial direction portion (axial length L3). Here, it is desirable that the axial length L3 of the crowning portion 23 is more than 100 μm and less than 400 μm. The radial length L2 of the crowning portion 23 is preferably shorter than 800 μm. Thereby, the curvature of the radial direction part in the crowning part 23 becomes larger than the curvature of the axial direction part. As a result, the gap between the raceway surfaces 18a and 19a of the races 18 and 19 and the outer peripheral surface of the cylindrical roller 21 can be gradually reduced, without impairing the advantage of preventing the occurrence of edge loading, The operation of the thrust roller bearing can be stabilized (for example, prevention of abnormal noise during operation).

  In the thrust roller bearing 200 of the present embodiment, a crowning portion (roller-side crowning portion 27) is also provided on the inner peripheral edge and the outer peripheral edge of each cylindrical roller 21. The total length Lb of the cylindrical roller 21 is longer than the length L1 of the flat surface portion 24 and shorter than the length La of the raceway surface 18a.

  The operation of the thrust roller bearing 200 of this embodiment will be described. As shown in FIG. 3, the inner race 18 has an annular shape protruding from the shaft portion 14 of the swash plate 13 only at the outer peripheral edge portion of the main surface S2 (the surface on which the raceway surface 18a is not provided). It is in contact with the convex portion 14a. The outer race 19 is in contact with an annular convex portion 11a projecting from the boss portion 11 of the cylinder 1 only at the inner peripheral edge portion of the main surface S2. A preload F is applied to the inner and outer races 18 and 19 along the axial direction. Then, as shown in FIG. 5, the inner and outer races 18 and 19 bend. In addition, the thrust roller bearing 200 of the present embodiment has the outer diameters of the races 18 and 19 smaller than those of the conventional ones in order to reduce weight and size, and the raceway surfaces 18a and 19a of the races 18 and 19 can be reduced. Is a little longer than the total length Lb of each cylindrical roller 21 (see FIG. 4). For this reason, the inner peripheral edge and the outer peripheral edge of the cylindrical rollers 21 of the races 18 and 19 are pressed against each other, and an edge load may occur.

  However, each of the races 18 and 19 of the thrust roller bearing 200 of the present embodiment is provided with respective crowning portions 23 at the inner peripheral edge portion and the outer peripheral edge portion thereof. For this reason, even if the races 18 and 19 are bent, the peripheral edge portion of the end surface of the cylindrical roller 21 and the flat portion 24 of the races 18 and 19 are difficult to directly contact with each other. . And since each roller side crowning part 27 is provided also in the inner peripheral part and outer peripheral part of each cylindrical roller 21, generation | occurrence | production of an edge load is prevented more reliably. As a result, the races 18 and 19 are not easily damaged, and the life of the thrust roller bearing 200 is extended.

  Next, the manufacturing method of the inner race 18 in the thrust roller bearing 200 of the present embodiment will be described. The inner race 18 is formed by punching a metal plate into a predetermined shape by a punching press (for example, a fine blanking press). As shown in FIGS. 6A and 6B, the fine blanking press mold 300 is formed of a combination of an upper mold 28 (punch) and a lower mold 29 (die). The upper die 28 includes an inner punch 31 and an annular outer punch 32 that are concentrically disposed, and an upper guide 33 that is disposed on the outer side in the vicinity of the outer punch 32. On the lower end surface of the upper guide, a protrusion 33a having an acute-angled tip is provided over the entire circumference. The inner and outer punches 31 and 32 and the upper guide 33 can be moved up and down separately. Further, a lower guide 34 having the same diameter as the inner punch 31 is provided immediately below the inner punch 31 in the lower die 29, and an annular discharge hole corresponding to the outer punch 32 is directly below the outer punch 32. 35 is provided. A plurality of ejector pins 36 are provided between the lower guide 34 and the discharge hole 35.

  As shown in FIG. 7A, a workpiece 37 (metal plate) is placed on the lower mold 29. First, only the upper guide 33 is lowered and presses the workpiece 37. The protrusion 33a of the upper guide 33 bites into the upper surface portion of the workpiece 37, and the workpiece 37 is pressed firmly. Moreover, since the force which raises also acts on the lower side guide part 34, the to-be-processed object 37 is pressed also from the downward direction. Thereby, a hydrostatic pressure acts on the workpiece 37.

  In this state, as shown in FIGS. 7B and 8C, the inner and outer punches 31 and 32 are lowered to punch the workpiece 37, and the inner peripheral surface 25, the outer peripheral surface 26, An annular molded body 38 having a shape (the previous stage to become the inner race 18) is formed. At this time, since hydrostatic pressure always acts on the workpiece 37, the processing accuracy (surface roughness) between the inner peripheral surface 25 and the outer peripheral surface 26 becomes extremely good. Of the punched workpiece 37, the inner slag 37a is lowered between the upper and lower guides 33 and 34. Further, the outer slag 37 b is discharged from the discharge hole 35.

  After a predetermined time has elapsed, as shown in FIG. 8D, the inner and outer punches 31 and 32 and the upper guide 33 are sequentially raised, and then the lower guide 34 and the ejector pin 36 are raised. After the annular molded body 38 and the slag 37a are discharged, the workpiece 37 is moved, and the same process as described above is performed by punching.

  As shown in FIG. 9A, burr portions 39 associated with the punching process are formed on the inner peripheral edge and the outer peripheral edge of the upper surface of the annular molded body 38 immediately after being punched. Similarly, each extraction part 41 accompanying punching is formed in the inner peripheral part and the outer peripheral part of the lower surface. Therefore, it is necessary to polish the upper surface of the annular molded body 38 and remove each burr portion 39. Each extraction portion 41 is polished to form each crowning portion 23. Since the approximate shape of each punched portion 41 can be formed in advance by punching, the number of polishing steps can be reduced. As a result, as shown in FIG. 9B, the crowning portions 23 and the flat portions 24 are formed on the inner peripheral edge and the outer peripheral edge on the main surface S1 side, and the main surface S2 side is a flat surface. A shaped inner race 18 is formed. The outer race 19 is also manufactured in the same manner as described above.

  In the thrust roller bearing 200 of the above-described embodiment, the crowning portion 23 is provided only on the main surface S1 on the side where the cylindrical roller 21 is disposed, among the main surfaces S1, S2 of the inner and outer races 18, 19. However, you may form the crowning part 23 in both main surface S1, S2. FIG. 10 shows inner and outer races 42 and 43 in the thrust roller bearing 200 of the embodiment in that case.

  In this specification, the case where the crowning portions 23 of the inner and outer races 18 and 19 are formed by polishing the extracted portions 41 formed by punching processing has been described. However, the crowning portion 23 may be formed by polishing a right-angled corner portion in each of the races 18 and 19 (that is, a corner portion in a state where the extracted portion 41 is not formed).

1 is a front sectional view of a swash plate compressor 100. FIG. It is the XX sectional view taken on the line of FIG. It is an enlarged view of the A section of FIG. 3 is an enlarged view of an inner race 18. FIG. It is an operation explanatory view of strut bearing 200. (A) is a schematic front sectional view of the molding die 300 of the fine blanking press, and (b) is a view taken in the direction of arrow Y in (a). (A), (b) is operation | movement explanatory drawing of a fine blanking press. (C), (d) is an operation explanatory drawing similarly. (A) is an expanded sectional view of the principal part of the to-be-punched workpiece 37, (b) is sectional drawing of the state which excised the burr part 39. FIG. It is sectional drawing of the thrust roller bearing 200 which uses the inner race 42 by which the crowning part 23 was provided in both main surfaces S1, S2.

Explanation of symbols

100: Swash plate compressor 200: Thrust roller bearing 300: Molding die (punching press)
1: Cylinder
3: Piston
4: Rotating shaft
4a: Axis
13: Swash plate 18, 42: Inner race (1st race)
18a: Inner race track surface (first track surface)
19, 43: Outer race (second race)
19a: outer raceway surface (second raceway surface)
21: Cylindrical roller (rolling element)
23: Crowning Club
24: Plane portion
25: Inner peripheral surface
26: outer peripheral surface
27: Roller side crowning part
37: Work piece (metal plate)
39: Kaeri Club
41: Dripping portion
F: Preload
L2: radial length (length of crowning portion in radial direction)
L3: Axial length (length of crowning portion in axial direction)
S1, S2: Main surface

Claims (5)

An annular first race in which the first raceway surface of the rolling element is formed on the main surface;
The second raceway surface of the rolling element is formed in an annular shape formed on the main surface, and the first raceway surface and the second raceway surface are arranged so as to face each other in the axial direction, and the first race A second race that rotates relative to the first race around an axis in a state where the rolling member is interposed between the rolling race and the preload is biased toward the first race via the rolling member. With
A crowning portion that is curved in a convex shape toward the arrangement space of the rolling elements is formed on each of the inner peripheral edge portion and the outer peripheral edge portion of the first and second raceway surfaces. Thrust roller bearing. The rolling element is a cylindrical roller,
In the first and second raceway surfaces, a flat surface portion in contact with the cylindrical roller is formed at a radial intermediate position from the inner peripheral edge portion to the outer peripheral edge portion,
2. The thrust roller bearing according to claim 1, wherein the crowning portion is formed in a form following an outer peripheral surface or an inner peripheral surface of the race from an end edge in a radial direction of the flat portion.   In the first and second races, the crowning portion is formed only on one main surface of the main surfaces on which the raceway surface is formed, and the other main surface is a flat surface. The thrust roller bearing according to claim 1 or 2. In the first race, the main surface opposite to the main surface on which the first raceway surface is formed, only the outer peripheral edge thereof is partially biased toward the second race,
The second race has a main surface opposite to the main surface on which the second raceway surface is formed, and only the inner peripheral edge thereof is partially biased toward the first race. The thrust roller bearing according to any one of claims 1 to 3, wherein   3. A roller-side crowning portion having a shape in which the distance from the rotational axis of the cylindrical roller decreases toward the end surface of the outer peripheral surface of the cylindrical roller. The thrust roller bearing according to any one of 4.

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