JP2012097872A - Retainer for bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive retainer for a bearing which is maintained or increased in wear resistance and sliding resistance and reduced in the rate of torque loss.SOLUTION: This retainer for a bearing includes a plurality of pockets for rotatably holding a plurality of respective rolling elements arranged along a mating member, and is revolved along the mating member together with the rolling elements. A surface hardening treatment is applied to the portions of the entire surface of the retainer which face at least the mating member and the rolling elements. In the surface hardening treatment, the portions of the retainer is coated with tin or a metal material containing tin to form a film of 1-20 μm in thickness thereon.

Description

  The present invention relates to a bearing retainer that can reduce heat generation and wear generated with a mating member and reduce torque loss.

  2. Description of the Related Art Conventionally, various bearings have been applied to portions where members rotate relative to each other such as an automatic transmission (AT) of an automobile and a torque converter. As an example, for example, Patent Document 1 discloses a thrust roller bearing that rotates while mainly supporting an axial load (or both an axial load and a radial load).

  In the thrust roller bearing of Patent Document 1, the cage is coated with a diamond-like carbon coating material or a ceramic coating material, for example, on a portion in sliding contact with a mating member (for example, inner and outer rings). Thereby, reduction of the heat_generation | fever which arises between the said holder | retainer and the other member, abrasion, etc. is achieved.

JP 2006-189133 A

  By the way, in various bearings including the bearing of the above-mentioned Patent Document 1, it is known that torque loss occurs during rotation of the bearing. Here, the ratio of factors causing torque loss is 60% rolling resistance between the cage and the rolling element, 20% stirring resistance between the cage and the lubricant, and the cage and the counterpart member (for example, inner and outer rings). The frictional resistance is considered to be about 20%.

  Therefore, there is a demand for the development of a bearing cage that can maintain and improve the wear resistance and sliding resistance and can reduce the above-mentioned ratio of torque loss. Specifically, by subjecting the cage to surface hardening treatment, the rolling resistance between the cage and the rolling element and the frictional resistance between the cage and the counterpart member (for example, inner and outer rings) are reduced. It is desired to reduce the ratio of factors causing torque loss due to each resistance (total: 80%). In this case, in the surface hardening treatment, there is a demand for cost reduction while maintaining and improving wear resistance and sliding resistance.

  The present invention has been made to meet such demands, and its purpose is to maintain and improve wear resistance and sliding resistance, and to reduce the rate of torque loss. The object is to provide a bearing cage.

In order to achieve such an object, the present invention has a plurality of pockets for rotatably holding a plurality of rolling elements arranged along the mating member one by one, and the mating member is attached to each of the rolling elements. A bearing cage that revolves along the surface, and the cage has been subjected to a surface hardening treatment at least in a portion facing the counterpart member and each rolling element of the entire surface. The corresponding part of the cage is coated with tin or a metal material containing tin to form a film having a thickness in the range of 1 to 20 μm.
In the present invention, the bearing cage described above is applied to a thrust bearing or a radial bearing, and holds a plurality of rolling elements in a rotatable manner.

  ADVANTAGE OF THE INVENTION According to this invention, while maintaining and improving abrasion resistance and sliding resistance, the low-cost bearing retainer which makes it possible to reduce the ratio of torque loss is realizable.

(a) is sectional drawing which partially expands and shows the arrangement configuration of the thrust bearing retainer which concerns on one Embodiment of this invention, (b) is the thrust bearing retainer which concerns on one Embodiment of this invention. Sectional drawing which expands and shows another arrangement configuration partially. (a) is a perspective view showing the overall configuration of the thrust bearing retainer shown in FIG. 1, and (b) is a configuration of one race of the thrust bearing retainer shown in FIG. FIG. 4C is a partially enlarged perspective view, and FIG. 4C is a partially enlarged perspective view showing the configuration of the other race of the thrust bearing retainer shown in FIG. The figure which shows the relationship between the rotation speed and the dynamic torque value in the bearing to which the cage coated with tin (Sn) is applied and the bearing to which the cage without tin coating is applied.

Hereinafter, a bearing cage according to an embodiment of the present invention will be described.
In the present embodiment, a bearing retainer that has a plurality of pockets that rotatably hold a plurality of rolling elements arranged along the mating member one by one, and revolves along the mating member together with the rolling elements. Suppose. Here, the bearing cage is applied to a thrust bearing or a radial bearing, and holds a plurality of rolling elements in a rotatable manner. In this case, a roller or a ball can be applied as the rolling element, but here, as an example, a thrust roller bearing retainer to which the roller is applied is assumed.

  As an example of the specifications of the thrust roller bearing cage, as shown in FIG. 1 (a), a pair of hollow annular races 2, 4 (also referred to as bearing washer) that are opposed to each other so as to be relatively rotatable. As shown in FIG. 1 (b), the first specification form in which the cage 6 is installed in between, and the cage 6 is directly incorporated in various rotating members 8 provided in an automatic transmission (AT) of an automobile, for example. A second specification form can be assumed.

  Here, in the 1st specification form of Drawing 1 (a), it becomes a pair of races 2 and 4 as a partner member, on the other hand, in the 2nd specification form of Drawing 1 (b), it becomes rotation member 8 as a partner member. However, the thrust roller bearing retainer 6 incorporated between the pair of races 2 and 4 according to the first specification will be described below.

  In this case, the thrust roller bearing retainer 6 (FIG. 1B) according to the second specification form has the same configuration as the thrust roller bearing retainer 6 according to the first specification form (FIG. 1A). Therefore, the reference numerals given to the respective configurations of the thrust roller bearing retainer 6 according to the first specification form described later are given to the respective configurations of the thrust roller bearing retainer 6 according to the second specification form. Thus, the description of the thrust roller bearing cage 6 according to the second specification form is omitted.

  As shown in FIG. 1 (a) and FIGS. 2 (a) to (c), a thrust roller bearing retainer 6 according to a first specification form is a hollow ring formed between a pair of races 2 and 4. The plurality of rolling elements (rollers) 10 arranged along the bearing inner space are revolved along the bearing inner space together with each of the rolling elements (rollers) 10 while being rotatably held one by one. In the drawing, as an example, in the pair of races 2 and 4, the left-side race in the figure is referred to as the inner race (inner raceway) 2, while the right-side race in the figure is referred to as the outer race (outer raceway). ).

  As the “roller” as the rolling element 10, for example, an elongated one having a small diameter and a length of 3 to 10 times the diameter is applied. The cage 6 may be any type (shape, form, etc.) as long as it can hold a plurality of rolling elements (rollers) 10 one by one along the bearing internal space. Then, as an example, two first and second hollow ring members 6a and 6b having L-shaped cross-sections having different diameters are prepared, and these hollow ring members 6a and 6b are integrated with each other. 6 is applied.

  Here, the first hollow ring member 6a is a hollow disk-shaped first annular part body 60 and perpendicular to the first annular part body 60 from both radial sides of the first annular part body 60. And a pair of first flange portions 60f that are parallel to each other and are continuous along the circumferential direction. In addition, the first annular portion main body 60 is formed with a plurality of first pocket constituting portions 60p opened in a rectangular shape at a predetermined interval (for example, at equal intervals) along the circumferential direction.

  On the other hand, the second hollow ring member 6b includes a hollow disk-shaped second annular part body 62 and a direction perpendicular to the second annular part body 62 from both radial sides of the second annular part body 62. And a pair of second flange portions 62f that are parallel to each other and continuous along the circumferential direction. The second annular portion main body 62 is formed with a plurality of second pocket constituting portions 62p that are opened in a rectangular shape at predetermined intervals (for example, at equal intervals) along the circumferential direction. In addition, the number of the 1st pocket structure parts 60p and the number of the 2nd pocket structure parts 62p are mutually set the same.

  In this case, the pair of first flange portions 60f of the first hollow ring member 6a and the pair of second flange portions 62f of the second hollow ring member 6b are overlapped with each other, and the first pocket constituting portion 60p By making the second pocket constituting portion 62p face each other (facing), one pocket 6p is formed between the first and second pocket constituting portions 60p, 62p. As a result, a plurality of pockets 6p are formed in the retainer 6 at a predetermined interval (for example, at equal intervals) along the circumferential direction, and each rolling element (roller) 10 can rotate one by one in each pocket 6p. Retained.

  In the drawing, as an example, in the cage 6 in which the first and second hollow ring members 6a and 6b are integrated with each other, the pair of first flange portions 60f is outside the pair of second flange portions 62f. In contrast to this, the pair of first flange portions 60f may be disposed and configured inside the pair of second flange portions 62f. Hereinafter, the cage 6 in which the pair of first flange portions 60f are arranged and configured outside the pair of second flange portions 62f is between the pair of races 2 and 4 (between the inner race 2 and the outer race 4). The explanation is continued assuming that it is incorporated.

  First, the inner race 2 is continuous from the hollow disc-shaped inner race main body portion 2a and the inner peripheral edge of the inner race main body portion 2a, and extends toward the outer race 4 so as to cover the bearing inner space (the cage 6). And an inner lip portion 2b that is taken out. The inner race main body portion 2a is not particularly denoted by a reference symbol, but an inner raceway surface (a plurality of rolling elements (rollers)) continuous along the circumferential direction on the inner peripheral surface (the opposing surface facing the outer race 4). ) A surface on which 10 rolls is formed. In addition, inner locking pieces 2t that are integrally formed by bending a part of the inner lip portion 2b toward the bearing internal space (the cage 6) are provided at predetermined intervals along the circumferential direction. ing.

  On the other hand, the outer race 4 is continuous from the hollow disc-shaped outer race main body portion 4a and the outer peripheral edge of the outer race main body portion 4a, and extends toward the inner race 2 so as to cover the bearing inner space (the cage 6). And an outer lip portion 4b. The outer race main body portion 4a is not particularly denoted by a reference numeral, but an outer raceway (a plurality of rolling elements (rollers)) which is continuous along the circumferential direction on the inner peripheral surface thereof (an opposing surface facing the inner race 2). ) A surface on which 10 rolls is formed. In addition, outer locking pieces 4t, which are integrally formed by bending a part of the outer lip portion 4b toward the bearing internal space (the cage 6), are provided at predetermined intervals along the circumferential direction. ing.

  In such a thrust roller bearing (also referred to as a thrust needle bearing), in the state where the rolling elements (rollers) 10 are held between the inner race 2 and the outer race 4 while being held by the cage 6, the inner locking described above is performed. When the piece 2t and the outer locking piece 4t are partially engaged with the cage 6 (specifically, engaged so as to hold the cage 6 from both sides), the bearing configuration (the inner race 2, The outer race 4, the cage 6, and the rolling elements (rollers) 10) are integrated without being separated from each other and maintained in an assembled state (non-separated state, anti-barre state).

  In a state where the thrust roller bearings are assembled between members (not shown) that relatively rotate, the plurality of rolling elements (rollers) 10 held by the cage 6 are interposed between the inner race 2 and the outer race 4. It can rotate while contacting along. In this state, when both members rotate relative to each other and the inner race 2 and the outer race 4 rotate relative to each other, a plurality of rolling elements (rollers) 10 are placed between the inner race 2 and the outer race 4. By rolling along, the cage 6 revolves along the mating member (that is, the pair of races 2 and 4) together with the rolling elements (rollers) 10.

  By the way, the cage 6 according to the first specification form maintains and improves its wear resistance and sliding resistance during the revolution of the cage 6 as described above, and reduces the ratio of torque loss. The technical idea for it is given. That is, the retainer 6 is subjected to a surface hardening treatment on at least a portion of the entire surface facing the counterpart member (the pair of races 2 and 4) and the rolling elements (rollers) 10.

  As a part where the cage 6 faces the mating member (a pair of races 2 and 4) and each rolling element (roller) 10, for example, a first hollow ring member facing the inner race body 2a of the inner race 2 is used. 6a (first annular portion main body 60) outer surface 60s, first hollow annular member 6a (one first flange portion 60f) facing the inner lip portion 2b of the inner race 2, inner surface 60r, outer race 4 The outer surface 62s of the second hollow ring member 6b (second ring portion main body 62) facing the outer race body portion 4a of the outer race 4 and the first hollow ring member 6a (other side) facing the outer lip portion 4b of the outer race 4 Of the first and second pocket components 60p, 62p constituting the outer diameter surface 60t of the first flange portion 60f) and the respective pockets 6p for rotatably holding the respective rolling elements (rollers) 10 one by one. Consider the shape of the opening surface 60h, 62h, etc. It can be.

  In the surface hardening process, the corresponding part of the cage 6 is coated with tin (Sn) or a metal material containing tin to form a film having a thickness in the range of 1 to 20 μm. In addition, as a formation method of a film, the existing methods, such as plating and coating, can be applied, for example. In short, any method that can form a film having a thickness in the range of 1 to 20 μm may be used. In addition, in the metal material containing tin, since content of the said tin is set according to the use environment and the intended purpose of the said holder | retainer 6, it does not specifically limit here. In short, it is sufficient that tin is contained to such an extent that the wear resistance and sliding resistance can be maintained and improved and the ratio of torque loss can be reduced.

  In this case, the entire surface of the cage 6 (first and second hollow ring members 6a and 6b) may be subjected to the surface hardening treatment as described above. In the thrust roller bearing retainer 6 (FIG. 1B) according to the second specification form, for example, the rotating member 8 is a part facing the mating member (rotating member 8) and each rolling element (roller) 10. The outer surface 62s of the second hollow ring member 6b (second ring portion main body 62) that faces the outer surface of the first hollow ring member 6a (the other first flange portion 60f) that faces the rotating member 8 60t, and rectangular opening surfaces 60h and 62h of the first and second pocket constituting portions 60p and 62p constituting each pocket 6p that holds each rolling element (roller) 10 so as to be rotatable one by one are assumed. be able to.

  Here, in the thrust roller bearing to which the cage 6 according to the first specification form is applied, the entire surface of the cage 6 (first and second hollow ring members 6a, 6b) or the above-described corresponding portion, For example, the dynamic torque value when tin (Sn) was coated and the state change of the tin coating were measured. In this measurement, two types of thrust roller bearings are prepared, the load on each of the bearings is maintained at 700 N (Newton), and special lubricating oil (ATF oil) containing a special friction modifier is maintained at 80 ° C. While filling the bearing at a rate of 50 mL (milliliter) per minute [50 mL / min], the rotational speed of the bearing (race 2, 4) is changed to 1000-9000 rpm [rpm] per minute. The measurement result was obtained.

  In the two types of thrust roller bearings (first and second bearings), the first bearing has a bearing outer diameter of 75 mm, a bearing inner diameter of 58 mm, a bearing width of 4.6 mm, a diameter of 3 mm, and a length. 47 rolling elements (rollers) 10 of 3.6 mm are incorporated between the races 2 and 4, and five of these rolling elements (rollers) 10 held by the cage 6 according to the first specification form (( 1) -1 to 5) were prepared. On the other hand, as the second bearing, the outer diameter of the bearing is 75 mm, the inner diameter of the bearing is 58 mm, the bearing width is 4.6 mm, the rolling element (roller) 10 having a diameter of 2 mm and a length of 3.6 mm is connected between the races 2 and 4. 34 (5) ((2) -1 to 5) were prepared in which each of these rolling elements (rollers) 10 was held by the cage 6 according to the first specification form.

  And these 1st and 2nd bearings are compared with embodiment ((1) -1-3, (2) -1-3) and comparative form ((1) -4,5, (2) -4,5). In the comparative embodiment, the cage 6 is not coated with a tin film ((1) -4, (2) -4) and the tin film with a thickness of 30 μm is coated ((1)- 5, (2) -5). In the embodiment, the cage 6 was coated with a tin film in a thickness range of 1 to 20 μm (see Table 1 below). As an example in Table 1, in the embodiment ((1) -1 to 3), when the thickness of the tin coating is set to 2, 5, 10 μm, the embodiment ((2) -1 to 3) ) Shows the case where the thickness of the tin coating is set to 1,5,20 μm.

  As described above, according to the measurement result according to the present embodiment, the dynamic torque value [N · m] of the bearing when tin (Sn) is coated on the entire surface of the cage 6 or the above-described corresponding portion is represented by the tin coating. It was confirmed that the dynamic torque value [N · m] of the bearing can be significantly reduced in the absence of the torque. In this case, it was confirmed that the dynamic torque value can be significantly reduced by setting the thickness of the tin coating in the range of 1 to 20 μm as compared with the case where the tin coating with a thickness of 30 μm is coated.

  In FIG. 3, as an example, a bearing ((1) -1) to which a cage 6 coated with tin (Sn) with a thickness of 2 μm is applied and a cage 6 coated with tin (Sn) with a thickness of 5 μm are applied. The relationship between the rotational speed and the dynamic torque value is shown in the bearing ((2) -2) and the bearing ((1) -4, (2) -4) to which the cage 6 without the tin coating is applied. Has been.

  According to this, the dynamic torque value of the bearing with the tin coating ((1) -1, (2) -2) is 0.05 to 0.07 [N · m] at a bearing rotational speed of 2000 [rpm]. This range is significantly lower than the dynamic torque values of 0.10 to 0.15 [N · m] of the bearings without tin coating ((1) -4, (2) -4). This confirms the measurement results in Table 1 above.

  As a result, the surface hardening treatment as described above is performed on the cage 6, so that the same resistance as that of a conventionally used surface hardening material (for example, diamond-like carbon coating material, ceramic coating material) is obtained. Abrasion and sliding resistance can be maintained and improved. As a result, it is possible to reduce heat generation and wear generated between the cage 6 and the mating member (the pair of races 2 and 4). .

  Furthermore, by subjecting the cage 6 to the surface hardening treatment as described above, the rolling resistance between the cage 6 and the plurality of rolling elements (rollers) 10, and the cage 6 and the mating member (a pair of races 2, 4). The frictional resistance with the rotating member 8) can be reduced, and the ratio of torque loss due to these resistances can be greatly reduced.

  Specifically, the ratio of the factor causing torque loss is 60% rolling resistance between the cage 6 and the plurality of rolling elements (rollers) 10, 20% stirring resistance between the cage 6 and the lubricant, The frictional resistance between the cage 6 and the mating member (the pair of races 2 and 4 and the rotating member 8) is considered to be about 20%. However, by applying the surface hardening treatment as described above to the cage 6, at least The ratio of torque loss over a total of 80% of rolling resistance (60%) and frictional resistance (20%) can be reduced.

  Further, in the surface hardening treatment as described above, tin (Sn) or tin which is less expensive than a surface hardening material (for example, a diamond-like carbon coating material or a ceramic coating material) generally used conventionally is used. Since the metal material to be contained can be used, the bearing cage 6 can be realized at a low cost.

In addition, this invention is not limited to above-described embodiment, The technical thought concerning the following modifications is also contained in the technical scope of this invention.
For example, in the above-described embodiment, the thrust roller bearing retainer 6 has been described. However, instead of this, the radial bearing retainer may be subjected to the same surface hardening treatment as described above. An effect can be realized. In this case, a roller or a ball can be applied as the rolling element, and a cage corresponding to the type of the rolling element is configured.

  In the above-described embodiment, the cage 6 in which the first and second hollow annular members 6a and 6b are integrated with each other is assumed. However, the present invention is not limited to this. For example, the first hollow Even if the above-mentioned surface hardening treatment is applied to the retainer 6 as a single-sheet retainer 6 composed of either the annular member 6a or the second hollow annular member 6b, the same effect is realized. can do.

2,4 race (partner)
6 Cage 6p Pocket 8 Rotating member (mating member)
10 Rolling elements (rollers)

Claims (2)

A bearing retainer that has a plurality of pockets for rotatably holding a plurality of rolling elements arranged along a mating member one by one, and revolves along the mating member together with each of the rolling elements,
The retainer is subjected to a surface hardening treatment on at least a portion facing the counterpart member and each rolling element, of the entire surface,
In the surface hardening treatment, a bearing cage is characterized in that tin or a metal material containing tin is coated on a corresponding portion of the cage to form a film having a thickness in the range of 1 to 20 μm.   The bearing retainer according to claim 1 is applied to a thrust bearing or a radial bearing, and retains a plurality of rolling elements in a rotatable manner.

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