JP2018162799A - Bearing lubrication structure of rotary device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing lubrication structure of a rotary device capable of preventing scattering of grease in grease lubrication.SOLUTION: At a lid 6 and an outer ring pressing member 18 positioned outside the right and left sides of an outer ring 12, annular recesses 24, 25 used as a grease reservoir are provided. In the recesses 24, 25, grease G is encapsulated. In order to hold the grease G, each surface 24a, 24b, 25a, 25b forming the recesses 24, 25 is a surface whose surface roughness is relatively rough.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bearing lubrication structure for a rotating device suitable for use in a machine tool having a main shaft rotatably supported by a plurality of bearings.

  In recent years, bearings used in machine tool spindles and the like are also required to be environmentally friendly and low cost. For this reason, there is no need to supply air or oil, and bearings using inexpensive grease lubrication have been reviewed.

  For bearings that use grease lubrication, lubrication is performed only with the grease that was enclosed when the bearing was assembled. For this reason, if the dn value (bearing diameter x rotating body rotation speed) increases, the grease deteriorates due to bearing heat generation or the base oil leaks, resulting in oil film breakage on the rolling surface, seizure, and grease lubrication life. There is a problem that cannot be completed.

  Therefore, as a means for extending the lubrication life of grease, there is one in which a grease holding groove (grease reservoir) is provided in a collar which is a fixing member (Patent Document 1).

JP 2007-333016 A

  However, there are problems with the prior art. The temperature around the bearing is high due to the heat generated by the bearing during rotation. For this reason, the grease exists in a softened state on the leaked base oil. A strong wind blows around the bearing due to the rotation. For this reason, even when a grease reservoir is provided, there is a problem that the grease on the base oil is easily blown to the outside and scattered so that peripheral grease and base oil are lost.

  An object of the present invention is to provide a bearing lubrication structure for a rotating device that can prevent grease from scattering in grease lubrication.

  A bearing lubrication structure for a rotating device according to the present invention includes an outer ring portion having a rolling surface, includes a fixing member fixed to a cylindrical housing, and an inner ring portion having a rolling surface, and is fixed to a rotating shaft. And a bearing lubrication structure that uses grease to lubricate the bearing, and a grease holding surface having a relatively rough surface is formed on a portion of the fixed member excluding the rolling surface. It is characterized by this.

  In the fixing member, the surface roughness of the rolling surface of the inner peripheral surface of the outer ring portion is set to a predetermined value or less so as not to prevent smooth rolling of the rolling elements. On the other hand, a surface having a surface roughness rougher than that of the rolling surface is formed as a grease holding surface for holding grease in a portion excluding the rolling surface. The rough surface may be the entire portion except the rolling surface, or may be a part of the portion excluding the rolling surface. The fixing member (for example, the outer ring pressing member that contacts the outer ring) is preferably formed with a grease reservoir comprising an annular recess as a portion for holding the grease. In this case, at least all surfaces of the annular recess are formed. Is a rough surface, and it is more preferable that the surface connected to the annular recess is also a rough surface. The roughened surface becomes the grease holding surface, and the grease on the grease holding surface is difficult to slip and is difficult to scatter against the wind generated by the bearing.

  According to the bearing lubrication structure of the rotating device of the present invention, the grease on the grease holding surface is difficult to slip, so that it is difficult to scatter against the wind generated by the bearing. Therefore, by retaining the grease over a long period of time, the lubrication performance can be maintained for a long period of time and the bearing life can be completed.

  The grease holding surface is preferably formed so that a processing mark remains in the circumferential direction. In this case, since the processing is easy, the bearing lubrication structure can be made inexpensive.

  The grease holding surface is preferably formed by turning, and the other surfaces are preferably formed by grinding the turning surface. If it does in this way, a part of finishing process can be abbreviate | omitted, and also it can make it difficult to disperse | distribute grease while obtaining the effect of reducing cost.

  Furthermore, it is preferable that the clearance between the fixed member and the rotating member is φ0.2 mm or less. This makes it difficult for the grease to enter the narrow gap, so that the grease is held for a longer period and the lubrication performance is maintained for a longer period.

  According to the bearing lubrication structure of the rotating device of the present invention, the grease is not scattered by the wind and the bearing can be continuously lubricated, so that the bearing life can be completed. Further, since it can be realized only by increasing the surface roughness of the processed surface, it can be performed at low cost.

FIG. 1 is a longitudinal sectional view showing an embodiment of a bearing lubrication structure for a rotating device of the present invention. FIG. 2 is an enlarged longitudinal sectional view of a main part of FIG.

  Hereinafter, an embodiment of a bearing lubrication structure for a rotating device according to the present invention will be described with reference to FIGS. 1 and 2. In the following description, the left and right in FIG.

  FIG. 1 shows a part of a spindle device (an example of a rotating device) of a machine tool. The spindle device (1) includes a cylindrical housing (2) and a hollow spindle (rotating) passed through the cylindrical housing (2). (Shaft) (3), and a built-in type electric motor (4) and a bearing (5) disposed between the housing (2) and the main shaft (3) which is a rotating shaft.

  A lid (6) is fixed to the right end of the housing (2) so as to substantially cover the right surface of the electric motor (4).

  The electric motor (4) includes a rotor (4a) provided on the outer periphery of the main shaft (3) and a stator (4b) provided on the inner periphery of the housing (2).

  The bearing (5) is composed of an inner ring (11) fixed to the main shaft (3), an outer ring (12) fixed to the lid (6), and a plurality of rollers (rolling elements) arranged between both wheels (11) (12). ) (13), and grease is used for lubrication. Rolling surfaces (11a) and (12a) on which the rollers (13) roll are formed on the outer peripheral surface of the inner ring (11) and the inner peripheral surface of the outer ring (12), respectively.

  A step portion (3a) is provided on the outer periphery of the main shaft (3), and the inner ring (11) is positioned by coming into contact with the spacer (14) received by the step portion (3a) from the right side. ing.

  An inner ring pressing member (15) is disposed on the right side of the inner ring (11), and is fixed to the main shaft (3) while being in contact with the inner ring (11).

  The inner ring pressing member (15) includes a cylindrical portion (16) and an outward flange portion (17) provided at the right end of the cylindrical portion (16).

  An outer ring pressing member (18) is disposed on the right side of the outer ring (12), and is fixed to the lid (6) in contact with the outer ring (12).

  The lid (6) includes a cylindrical portion (19) located on the radially outer side of the outer ring (12), an inward flange portion (20) provided at the left end of the cylindrical portion (19), and a cylindrical portion (19). And an outward flange portion (21) provided at the right end portion of the.

  The cylindrical portion (19) has an inner diameter substantially equal to the outer diameter of the outer ring (12), and the outer ring (12) is fitted into the cylindrical portion (19), and the left surface thereof is an inward flange portion (20 ) Is in contact with the right surface of the lens.

  The outward flange portion (21) is fitted into the right end portion of the housing (2) at the outer edge thereof, and is in contact with the step portion (2a) provided on the inner periphery of the housing (2). An annular left protrusion (21a) fitted on the inner periphery of the housing (2) is provided on the outer edge of the outward flange portion (21).

  The outer ring holding member (18) is provided in the middle of the outer peripheral surface of the cylindrical portion (22) and the outer peripheral surface of the cylindrical portion (22) with the radially outer portion of the left surface contacting the right surface of the outer ring (12). It comprises an annular projecting portion (23) projecting outward. An annular notch (22a) is provided on the outer periphery of the portion on the right side of the protruding portion (23) of the cylindrical portion (22).

  In this embodiment, the lid (6), the outer ring (12), and the outer ring pressing member (18) are fixed members (7) fixed to the housing (2), and the spacer (14), the inner ring (11) The inner ring pressing member (15) is a rotating member (8) fixed to the main shaft (3). Between the inner peripheral surface of the lid (6) and the outer peripheral surface of the spacer (14) and between the inner peripheral surface of the outer ring pressing member (18) and the outer peripheral surface of the cylindrical portion (16) of the inner ring pressing member (15) A gap having a predetermined size is formed so as to prevent contact during rotation.

  On the right side of the inward flange portion (20) of the lid (6), an annular recess (24) is formed that opens rightward and radially inward and is used as a grease reservoir. In addition, an annular recess (25) is formed in the left portion of the cylindrical portion (22) of the outer ring pressing member (18), which opens leftward and radially inward and is used as a grease reservoir.

  Hereinafter, the bearing lubrication structure of the spindle device (1) will be described with reference to FIG.

  The bearing lubrication structure uses grease (G), and as described above, the recesses of the lid (6) used as grease reservoirs on the left and right outer sides of the outer ring (12) in the fixing member (7) ( 24) and a recess (25) in the outer ring retainer member (18) are provided, where grease (G) is sealed, and if necessary, grease is applied to the inner peripheral surface of the outer ring (12). (G) is applied. The base oil exuded from the grease (G) is supplied to the rolling surface (12a) of the outer ring (12), and is also supplied to the rolling surface (11a) of the inner ring (11) via the rollers (13). As a result, the bearing (5) is lubricated and the durability of the bearing (5) is ensured.

  Each of the recesses (24) and (25) is formed with a relatively rough surface so that the grease (G) is easily held.

  That is, the rolling surfaces (11a) and (12a) of the inner ring (11) and the outer ring (12) have a surface roughness of a predetermined value or less in order to make the rollers (13) roll smoothly. In contrast to this, the bottom surface (24a) (25a) and the outer peripheral surface (24b) (25b) of each recess (24) (25) are formed so as to leave a processing mark in the circumferential direction. Thus, the surface is rougher than the rolling surfaces (11a) and (12a).

  Specifically, the bottom surface (24a) (25a) and the outer peripheral surface (24b) (25b) of each recess (24) (25), the surface roughness such as the rolling surface (11a) (12a) is the center line The average roughness Ra is about 1.6 μm, whereas the surface roughness is about the center line average roughness Ra = 25 μm. The surface roughness of the bottom surface (24a) (25a) and the outer peripheral surface (24b) (25b) of each recess (24) (25) is preferably a center line average roughness Ra = 25 μm or more.

  The grease (G) enclosed in the recesses (24) and (25) has a large friction on the bottom surface (24a) (25a) and outer peripheral surfaces (24b) (25b), which are rough surfaces, and is difficult to slip. Therefore, the grease (G) and the base oil are prevented from being scattered even with the wind generated in the bearing (5) as the main shaft (3) rotates. Thus, the lubricating performance by the grease (G) is maintained over a long period.

  The gap (P1) between the inner peripheral surface of the inward flange portion (20) of the lid (6) and the outer peripheral surface of the spacer (14), and the inner peripheral surface of the cylindrical portion (22) of the outer ring holding member (18) The gap (P2) between the inner ring pressing member (15) and the outer peripheral surface of the cylindrical portion (16) has been conventionally φ0.5 mm or more (diameter difference of 0.5 mm or more). Is set to φ0.2 mm or less (diameter difference is 0.2 mm or less).

  This makes it difficult for the grease (G) enclosed in the recesses (24) and (25) to enter the narrow gaps (P1) and (P2) and moves from where the grease (G) is sealed. It becomes difficult. This also maintains the lubrication performance with the grease (G) over a long period of time.

  When the fixing member (7) is processed, the lid (6) and the outer ring pressing member (18) are turned into a required shape by turning, and then finished by grinding and subsequent processing. At this time, the recesses (24) and (25) are not subjected to grinding, thereby leaving a circumferential mark formed during the turning of the recesses (24) and (25). Thus, as for the machining process, instead of adding a new process, by omitting a part of the finishing process, the bottom surface (24a) (25a) and the outer peripheral surface (24b) of each recess (24) (25) ) (25b) can be a relatively rough surface.

  Regarding the portion of the inner peripheral surface of the outer ring (12) excluding the rolling surface (12a), the bottom surface (24a) (25a) and outer peripheral surface (24b) (25b) of each recess (24) (25) ) Or a rough surface between the bottom surface (24a) (25a) and the outer peripheral surface (24b) (25b) of each recess (24) (25) and the rolling surface (12a). Accordingly, the effect of preventing the grease (G) and the base oil from being scattered on the inner peripheral surface of the outer ring (12) can be obtained. A portion other than the rolling surface (11a) of the inner ring (11) may be a rough surface. The parts other than the recesses (24) and (25) of the lid (6) and outer ring pressing member (18) are ground in the same manner as in the past, so that points other than the grease (G) holding performance can be obtained. As for, the same performance as the conventional one is maintained.

(1): Spindle device (rotating device)
(2): Housing
(3): Main shaft (rotating shaft)
(5): Bearing
(7): Fixed member
(8): Rotating member
(11): Inner ring (inner ring part of rotating member)
(11a): Rolling surface
(12): Outer ring (outer ring part of fixed member)
(12a): Rolling surface
(24): Recess (grease reservoir)
(24a): Bottom (grease holding surface)
(24b): Outer peripheral surface (grease holding surface)
(25): recess (grease reservoir)
(25a): Bottom (grease holding surface)
(25b): Outer peripheral surface (grease holding surface)
(G): Grease
(P1): Clearance
(P2): Clearance

Claims (4)

A rotating device including an outer ring portion having a rolling surface and fixed to a cylindrical housing, and a rotating device including an inner ring portion having a rolling surface and fixed to a rotating shaft. A bearing lubrication structure that uses grease for lubrication,
A bearing lubricating structure for a rotating device, wherein a grease holding surface having a relatively rough surface is formed on a portion of the fixed member excluding the rolling surface.   2. The bearing lubrication structure for a rotating device according to claim 1, wherein the grease holding surface is formed so as to leave a processing mark in the circumferential direction.   3. The bearing lubrication structure for a rotating device according to claim 1, wherein the grease holding surface is formed by turning, and the other surface is formed by grinding the turning surface.   The bearing lubrication structure for a rotating device according to any one of claims 1 to 3, wherein a gap between the fixed member and the rotating member is φ0.2 mm or less.

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