JP2014043872A - Cylindrical roller bearing, and support structure for shaft body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical roller bearing in which a shaft body can be made of an inexpensive material and which can prevent seizure on an outer race, and to provide a support structure for a shaft body using the cylindrical roller bearing.SOLUTION: A shaft body 1 having an axis in an up-down direction is rotatably supported by a cylindrical roller bearing 2. An inner race 21 of a cylindrical roller bearing 2 is constituted by a product formed by pressing a steel plate, and is fitted on the shaft body 1. A bearing flange part 21c provided in the inner race 21 receives a cylindrical roller 23 and a cage 24. A bottom edge face of a cage 24 sliding on the bearing flange part 21c is constituted by a steel slide ring 24b.

Description

  The present invention relates to a cylindrical roller bearing and a shaft support structure using the same.

  Conventionally, for example, a reduction gear used for a swing mechanism of a hydraulic excavator has an output shaft arranged with its axis line oriented in the vertical direction (see, for example, Patent Document 1). The output shaft is rotatably supported by a rolling bearing fitted in the housing. FIG. 4 is a cross-sectional view of an essential part showing an example of a structure for supporting the upper end portion of the output shaft. As shown in the figure, the upper end portion 101 a of the output shaft 101 is rotatably supported by a cylindrical roller bearing 102 as a rolling bearing fitted in the housing 103.

The cylindrical roller bearing 102 includes an inner ring 104 formed by the output shaft 101 itself, an outer ring 105 fitted in the housing 103, a plurality of cylindrical rollers 106 interposed between the inner ring 104 and the outer ring 105, and each cylindrical roller. And a cage 107 that holds 106 at regular intervals along the circumferential direction.
An inner ring raceway 104 a on which the cylindrical roller 106 rolls is formed on the outer periphery of the inner ring 104. The inner ring raceway 104a is hardened to a predetermined hardness by heat treatment and finished to a predetermined surface roughness by polishing.

An outer ring raceway 105 a on which the cylindrical roller 106 rolls is formed on the inner periphery of the outer ring 105. The outer ring raceway 105a is hardened to a high hardness by heat treatment and finished to a predetermined surface roughness by polishing.
An annular flange 105b protruding radially inward is formed on both upper and lower sides of the outer ring 105 across the outer ring raceway 105a. The lower flange 105b receives the cylindrical roller 106 and the cage 107, and Is restricted from falling. The flange 105b for receiving the cylindrical roller 106 and the cage 107 may be provided only on the lower side of the outer ring 105. In this case, when the outer ring 105 is fitted into the housing 103, the upper and lower portions of the outer ring 105 Since it is necessary to align the directions, the fitting work becomes complicated, which is not preferable.

JP-A-6-330537

  In the support structure of the output shaft 101, it is necessary to harden at least the inner ring raceway 104a portion with high hardness by heat treatment. Therefore, it is necessary to use an expensive material such as chrome molybdenum steel (SCM material) as the material of the output shaft 101. There is. As described above, in order to cure only a part of the output shaft 101, it is necessary to form the whole with an expensive material.

  Further, since the cylindrical roller 106 and the cage 107 are prevented from dropping by the lower flange 105b, the cylindrical roller 106 is placed on the inner side surface (upper surface) of the lower flange 105b when the output shaft 101 rotates. The end face of the slidably contacts with each other. Moreover, when skew occurs in the cylindrical roller 106, the contact surface pressure between the end surface of the roller 106 and the inner surface of each flange 105b increases. For this reason, due to poor lubrication or the like, the sliding contact surface between the end surface of the cylindrical roller 106 and the flange 105b may be seized and the bearing life may be reduced.

  The present invention has been made in view of the above problems, and a cylindrical roller bearing capable of preventing the bearing life from being reduced while the shaft body can be formed of an inexpensive material, and a shaft body using the same. It is an object to provide a support structure.

(1) A cylindrical roller bearing according to the present invention for achieving the above object is a cylindrical roller bearing for rotatably supporting a shaft body disposed inside a housing in a state where an axis is directed in the vertical direction. An inner ring having an inner ring raceway on the outer circumference and an inner ring fitted to the shaft body, and an outer ring provided concentrically with the inner ring and having an outer ring raceway on the inner circumference and the outer circumference fitted to the housing; A plurality of cylindrical rollers interposed between the inner ring raceway and the outer ring raceway, and a cage for holding the cylindrical rollers at regular intervals along the circumferential direction, the inner ring having the inner ring raceway on the outer periphery. And an inner ring cylindrical portion whose inner circumference is fitted to the shaft body, and a support collar portion that extends radially outward from a lower end of the inner ring cylindrical portion and receives the cylindrical roller together with a cage, and the whole is a steel plate. It consists of a press-molded product obtained by pressing A cage is provided between a pair of annular portions facing each other at a predetermined interval, and a pair of the annular portions that form a pocket that individually accommodates each cylindrical roller together with the pair of annular portions. A retainer body having a plurality of pillars, the entirety of which is made of synthetic resin, and an annular slide made of steel that is integrated with the lower end surface of the retainer body and is in sliding contact with the support collar. It is characterized by having a ring.

(2) Further, another cylindrical roller bearing according to the present invention is a cylindrical roller bearing for rotatably supporting a shaft body disposed inside the housing in a state where the axis is directed in the vertical direction. Cylindrical roller bearings have an inner ring raceway on the outer periphery and an inner ring fitted to the shaft body. The inner ring is concentric with the inner ring, and an outer ring raceway on the inner circumference and the outer circumference fits in the housing. An outer ring, a plurality of cylindrical rollers interposed between the inner ring raceway and the outer ring raceway, and a cage that holds the cylindrical rollers at regular intervals along the circumferential direction. The inner ring raceway has an inner ring cylindrical portion with an inner circumference fitted to the shaft body, and the whole is made of a press-molded product obtained by pressing a steel plate, and the outer ring is formed on the outer circumference on the outer ring. An outer ring cylindrical portion having a raceway and an outer periphery fitted into the housing, and the outer ring circle And a support flange portion that extends inward in the radial direction from the lower end of the portion and receives the cylindrical roller together with a cage, and is made of a press-molded product that is obtained by pressing a steel plate as a whole. A pair of annular portions that are spaced apart and opposed to each other, and a plurality of column portions that are spanned between both of the pair of annular portions and constitute a pocket that individually accommodates each cylindrical roller together with the pair of annular portions, A retainer body formed entirely of a synthetic resin, and an annular sliding contact ring made of steel that is integrated with the lower end surface of the retainer body and is in sliding contact with the support collar. It is characterized by.

According to the cylindrical roller bearing having the above configuration, the cylindrical roller and the cage can be received by the support collar portion, so it is necessary to provide a flange for restricting the cylindrical roller and the cage from dropping on the outer ring. Absent. For this reason, the seizure of the sliding contact surface between the cylindrical roller and the scissors, which has conventionally occurred, cannot occur.
Further, since the inner ring raceway having a high hardness can be formed by fitting the inner ring to the shaft body, it is not necessary to heat-treat the shaft body itself to a high hardness. For this reason, an inexpensive material can be used as the material of the shaft body.

(3) In the cylindrical roller bearing, it is preferable that an annular concave groove for storing a lubricant is provided in a portion of the bearing rod portion where the sliding contact ring comes into sliding contact.
In this case, it is possible to effectively lubricate the slidable contact surface between the bearing rod part and the slidable contact ring by the lubricant accumulated in the concave groove. For this reason, it is possible to effectively prevent both from being seized or abnormally worn.

(4) In the cylindrical roller bearing, it is preferable that the radial movement of the cage is regulated by the concave groove.
In this case, since the rotation of the cage can be guided by the support rod part, it is not necessary to separately provide a mechanism for guiding the rotation of the cage.

(5) In the cylindrical roller bearing according to (1), it is preferable that the inner ring includes a latching hook portion that extends radially inward from an upper end of the inner ring cylindrical portion and is latched on the shaft body.
In this case, since the hooking hook portion can be hooked to the shaft body in a state where the inner ring is fitted to the shaft body, the inner ring can be prevented from moving downward. For this reason, a cylindrical roller and a holder | retainer can be supported reliably.

(6) In the cylindrical roller bearing according to (2), it is preferable that the outer ring includes a latching hook portion that extends radially outward from an upper end of the outer ring cylindrical portion and is latched on the housing.
In this case, since the latching hook part can be latched to the housing in a state where the outer ring is fitted to the housing, the outer ring can be prevented from moving downward. For this reason, a cylindrical roller and a holder | retainer can be supported reliably.

The shaft body support structure according to the present invention rotatably supports a shaft body disposed inside the housing with the axis line directed in the vertical direction by a cylindrical roller bearing interposed between the shaft body and the housing. A supporting structure for the shaft body,
The cylindrical roller bearing is the cylindrical roller bearing described in any one of (1) to (6).
According to the support structure of the shaft body having the above-described configuration, the cylindrical roller bearings described in (1) to (6) have an action corresponding to each.

  According to the cylindrical roller bearing and the shaft body support structure according to the present invention, an inexpensive material can be used as the shaft body, and the sliding contact between the outer ring flange and the end surface of the cylindrical roller does not occur. It is possible to prevent the bearing life from decreasing.

It is principal part sectional drawing which shows the support structure of the cylindrical roller bearing and shaft body concerning one Embodiment of this invention. It is a principal part side view which shows the holder | retainer of the said cylindrical roller bearing. It is principal part sectional drawing which shows other embodiment. It is principal part sectional drawing which shows the support structure of the conventional shaft body.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a main part showing a shaft body support structure using a cylindrical roller bearing according to an embodiment of the present invention. The shaft body support structure is configured to rotatably support a shaft body 1 such as an output shaft of a reduction gear by a cylindrical roller bearing 2 fitted in a housing 3.

  The shaft body 1 is disposed inside the housing 3 with the axis L directed in the vertical direction. The cylindrical roller bearing 2 is interposed between the outer periphery of the upper end portion of the shaft body 1 and the housing 3. The cylindrical roller bearing 2 includes an inner ring 21 fitted to the shaft body 1, an outer ring 22 disposed concentrically with the inner ring 21 so as to provide a gap, and a plurality of intervening rings between the inner ring 21 and the outer ring 22. A cylindrical roller 23 and a cage 24 that holds the cylindrical roller 23 at regular intervals along the circumferential direction are provided.

  The inner ring 21 includes an inner ring cylindrical portion 21a whose inner periphery is fitted to the shaft body 1, an annular hooking flange portion 21b extending radially inward from the upper end of the inner ring cylindrical portion 21a, and an inner ring cylindrical portion 21a. And an annular bearing rod 21c extending radially outward from the lower end. The inner ring 21 is a press-formed product obtained by integrally forming a thin steel plate by press working. As the steel sheet, for example, carburized steel such as nickel chromium steel (SNC), nickel chromium molybdenum steel (SNCM), chromium steel (SCr), chromium molybdenum steel (SCM), and high / medium carbon steel are used.

  An inner ring raceway 21d is provided on the inner peripheral surface of the inner ring cylindrical portion 21a. At least the inner ring raceway 21d portion is hardened by heat treatment, and surface finish is given by barrel polishing or the like after the heat treatment. As the heat treatment, carburization, carbonitriding, induction hardening, or the like is employed depending on the material of the shaft body 1. Further, the inner periphery of the inner ring cylindrical portion 21 a is press-fitted into the outer periphery of the shaft body 1.

  The hooking collar portion 21 b is hooked to the shaft body 1 in a state along the outer peripheral side of the upper end surface of the shaft body 1. Accordingly, the position of the inner ring 21 in the vertical direction is defined, and the inner ring 21 is moved downward due to, for example, a difference in thermal expansion coefficient between the shaft body 1 and the inner ring 21 or a load that repeatedly acts on the inner ring 21. It is restricted from moving. Thus, since the inner ring 21 can be held at a fixed position by the latching hook portion 21b, it is necessary to form a protrusion, a step portion or the like for receiving the inner ring 21 and holding it at the fixed position on the shaft body 1 side. Absent.

  The bearing bar 21c slides against the lower end of the cage 24 and receives the cage 24, thereby restricting the cylindrical roller 23 from falling. An annular concave groove 21e for accumulating a lubricant is provided at a portion of the bearing rod portion 21c that receives the cage 24. A surface along the radial direction of the concave groove 21e is a concave curved surface.

The cage 24 includes an annular cage body 24a formed entirely of a synthetic resin, and an annular sliding contact ring 24b integrated with the cage body 24a.
The cage main body 24a has a pair of annular portions 24c that are spaced apart from each other and face each other, and a plurality of column portions 24d that are installed between the pair of annular portions 24c (see FIG. 2). ). The column portion 24d constitutes a plurality of pockets 24f that individually accommodate the cylindrical rollers 23 together with the annular portion 24c.

  A pair of upper and lower sliding rings 24b are provided and integrated with each annular portion 24c of the cage body 24a by insert molding. Each slidable contact ring 24b has an arc shape in which a central portion swells in a radial section, and an inner surface thereof matches an outer surface of the annular portion 24c. The sliding contact ring 24b is made of steel, and suppresses the retainer 24 from being worn by sliding contact with the bearing rod 21c.

The curvature of the convex curved surface on the outer surface of each sliding contact ring 24b is larger than the curvature of the concave curved surface in the concave groove 21e of the bearing collar 21c. As a result, the sliding contact ring 24b on the lower side is brought into sliding contact with the concave groove 21e in a state of line contact with the concave groove 21e of the support rod 21c as the retainer 24 rotates. At this time, the lubricant accumulated in the concave groove 21e can effectively lubricate the sliding contact surface between the bearing collar portion 21c and the sliding contact ring 24b, so that both can be effectively prevented from seizing. It is possible to effectively prevent both from being abnormally worn.
Note that a hard film such as diamond-like carbon (DLC) may be formed on the sliding surface of the sliding contact ring 24b with respect to the bearing collar portion 21c. In this case, the bearing collar portion 21c and the sliding surface are seized. Can be more effectively prevented.

  In addition, since the cage 24 can be restricted from moving in the radial direction by the concave groove 21e of the bearing collar portion 21c, the rotation of the cage 24 can be guided by the bearing collar portion 21c. For this reason, it is not necessary to separately configure a mechanism for guiding the rotation of the cage 24.

  The outer ring 22 has a cylindrical shape having an outer ring raceway 22d on the inner periphery. The outer ring 22 is a so-called wrinkle-free type that does not have a flange projecting radially inward on both sides in the axial direction across the outer ring raceway 22d. At least the outer ring raceway 22d portion of the outer ring 22 is hardened by heat treatment. The outer periphery of the outer ring 22 is press-fitted into the housing 3. The outer ring 22 is made of, for example, high / medium carbon steel or bearing steel.

  According to the support structure of the shaft body configured as described above, the cylindrical roller 23 and the cage 24 can be received by the support collar portion 21 c of the inner ring 21, so that the cylindrical roller 23 and the cage 24 fall on the outer ring 22. There is no need to provide a bag to regulate For this reason, since the sliding contact between the flange and the cylindrical roller 23 does not occur, there is no possibility of causing the conventional problem that the sliding contact surfaces of both of them are seized. Moreover, since the inner ring | wheel 21 can be hold | maintained in a fixed position by the latching hook part 21b, the cylindrical roller 23 and the holder | retainer 24 can be supported reliably.

  Further, since the inner ring raceway 21d is formed on the inner ring 21 fitted to the shaft body 1, it is not necessary to form the inner ring raceway on the shaft body 1 itself. Thereby, since it is not necessary to harden the shaft body 1 by heat treatment, an inexpensive material can be selected as the material of the shaft body. Moreover, materials other than steel materials, such as aluminum and a copper alloy, can also be selected as a material of the shaft body 1 according to a use.

FIG. 4 is a cross-sectional view showing another embodiment. This embodiment is mainly different from the embodiment shown in FIG. 1 in that the outer ring 22 is formed of a molded product obtained by press-molding a steel plate, and a support rod portion 22c extending radially inward is formed at the lower end portion thereof. It is a point.
More specifically, the outer ring 22 includes an outer ring cylindrical part 22a whose inner periphery is fitted to the housing 3, an annular hooking bar part 22b extending radially inward from the upper end of the outer ring cylindrical part 22a, and an outer ring. An annular bearing rod 22c extending radially inward from the lower end of the cylindrical portion 22a is provided. The outer ring 22 is a press-formed product in which a thin steel plate is integrally formed by pressing.

An outer ring raceway 22d is provided on the inner peripheral surface of the outer ring cylindrical portion 22a. At least the outer ring raceway 22d portion is hardened by heat treatment, and surface finish is given by barrel polishing or the like after the heat treatment.
The latching hook portion 22 b is hooked to the housing 3 by being along the step portion 31 of the housing 3. As a result, the position of the outer ring 22 in the vertical direction is defined, and the downward movement of the outer ring 22 is restricted.

The bearing bar 22 c receives the cylindrical roller 23 together with the cage 24. An annular concave groove 22e for storing a lubricant is provided in a portion of the bearing rod portion 22c that receives the cage 24. A surface along the radial direction of the concave groove 22e is a concave curved surface.
In addition, the inner ring | wheel 21 is comprised with the press-formed product which has only the cylindrical part 21a and the latching hook part 21b.

  According to this embodiment, since the cylindrical roller 23 and the cage 24 can be received by the support collar portion 22c of the outer ring 22, the collar of the outer ring 22 for restricting the cylindrical roller 23 and the cage 24 from falling. Is no longer necessary. For this reason, it can avoid that the conventional malfunction that the sliding contact surface of a collar and a cylindrical roller seizes arises. Moreover, since the outer ring | wheel 22 can be hold | maintained in a fixed position by the latching hook part 22b, the cylindrical roller 23 and the holder | retainer 24 can be supported reliably.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the case where the upper and lower slidable contact rings 24 b are provided is shown, but this may be provided only on the lower end side of the cage 24.
In addition, the cross-sectional shape of the concave grooves 21e and 22e of the bearing rod portions 21c and 22c may be not only the above-described curved shape but also other shapes such as a triangle. In this case, the sliding contact ring of the cage 24 The shape of 24b may also be a shape corresponding to the shape of the concave grooves 21e and 22e.

  DESCRIPTION OF SYMBOLS 1: Shaft body, 2: Cylindrical roller bearing, 3: Housing, 21: Inner ring, 21a: Inner ring cylindrical part, 21b: Hanging hook part, 21c: Bearing hook part, 21d: Inner ring track, 21e: Concave groove, 22: Outer ring, 22a: outer ring cylindrical part, 22b: retaining rod part, 22c: bearing collar part, 22d: outer ring raceway, 23: cylindrical roller, 24: cage, 24a: cage body, 24b: sliding ring, 24c: Ring part, 24d: pillar part, 24f: pocket, L: axis

Claims (7)

A cylindrical roller bearing for rotatably supporting a shaft body arranged inside a housing in a state where the axis is directed in the vertical direction,
An inner ring having an inner ring raceway on the outer periphery and an inner ring fitted to the shaft body; an outer ring provided concentrically with the inner ring and having an outer ring raceway on the inner circumference and the outer circumference fitted to the housing; and the inner ring A plurality of cylindrical rollers interposed between the raceway and the outer ring raceway, and a cage for holding the cylindrical rollers at regular intervals along the circumferential direction,
The inner ring has the inner ring raceway on the outer periphery and an inner ring cylindrical portion in which the inner periphery is fitted to the shaft body, and extends radially outward from a lower end of the inner ring cylindrical portion to receive the cylindrical roller together with a cage. It is provided with a bearing collar, and the whole consists of a press-formed product obtained by pressing a steel plate.
The retainer is configured to form a pair of annular portions opposed to each other with a predetermined interval therebetween, and a pocket that is spanned between the pair of annular portions and individually accommodates each cylindrical roller together with the pair of annular portions. A retainer body formed entirely of synthetic resin, and an annular body made of steel that is integrated with the lower end surface of the retainer body and is in sliding contact with the support collar. A cylindrical roller bearing comprising a sliding contact ring. A cylindrical roller bearing for rotatably supporting a shaft body arranged inside a housing in a state where the axis is directed in the vertical direction,
The cylindrical roller bearing has an inner ring raceway on the outer circumference and an inner ring fitted to the shaft body, and is provided concentrically with the inner ring, and has an outer ring raceway on the inner circumference and the outer circumference fits in the housing. An outer ring to be combined, a plurality of cylindrical rollers interposed between the inner ring raceway and the outer ring raceway, and a cage for holding the cylindrical rollers at regular intervals along the circumferential direction,
The inner ring has the inner ring raceway on the outer periphery and the inner ring has an inner ring cylindrical portion fitted to the shaft body, and the whole consists of a press-molded product obtained by pressing a steel plate,
The outer ring has the outer ring raceway on the inner periphery and the outer ring cylindrical portion whose outer periphery is fitted to the housing, and a support that extends radially inward from the lower end of the outer ring cylindrical portion to receive the cylindrical roller together with the cage And a collar part, and the whole consists of a press-formed product obtained by pressing a steel plate,
The retainer is configured to form a pair of annular portions opposed to each other with a predetermined interval therebetween, and a pocket that is spanned between the pair of annular portions and individually accommodates each cylindrical roller together with the pair of annular portions. A retainer body formed entirely of synthetic resin, and an annular body made of steel that is integrated with the lower end surface of the retainer body and is in sliding contact with the support collar. A cylindrical roller bearing comprising a sliding contact ring.   The cylindrical roller bearing according to claim 1 or 2, wherein an annular concave groove for storing a lubricant is provided in a portion of the bearing rod portion where the sliding contact ring is in sliding contact.   The cylindrical roller bearing according to claim 3, wherein movement of the cage in the radial direction is restricted by the concave groove.   The cylindrical roller bearing according to claim 1, wherein the inner ring includes a latching hook part that extends radially inward from an upper end of the inner ring cylindrical part and is latched on the shaft body.   The cylindrical roller bearing according to claim 2, wherein the outer ring includes a latching hook part that extends radially outward from an upper end of the outer ring cylindrical part and is latched on the housing. A shaft body support structure that rotatably supports a shaft body arranged inside the housing with the axis line directed in the vertical direction by a cylindrical roller bearing interposed between the shaft body and the housing,
The cylindrical roller bearing is a cylindrical roller bearing according to any one of claims 1 to 6, wherein the shaft body supporting structure is provided.

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