JP2007255458A - Sliding bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding bearing unit capable of supporting not only radial load but also thrust load from both directions inexpensively. <P>SOLUTION: This sliding bearing unit 1 is constituted in such a way that an inward member 2 fixed on an outer peripheral face of a shaft is rotatably stored on an inner side of an outward member 3, a radial bearing part 7 supporting radial load is formed on an outer peripheral side of the inward member 2, and thrust bearing parts 8, 9 supporting thrust load are formed on both end sides in the axial direction of the inward member 2, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sliding bearing unit, and more particularly to a sliding bearing unit that is preferably used for supporting a rotating shaft of a motor that drives a worm gear mechanism or the like.

  As is well known, rolling bearings reduce friction by the rolling contact of rolling elements interposed between a pair of drive wheels, and are widely used as bearings for general equipment due to their excellent low torque characteristics. Has been. Specifically, for example, the following Patent Document 1 discloses one that uses a rolling bearing as a bearing of a rotating shaft of a motor that drives a worm gear mechanism.

  However, since the rolling bearing is composed of a large number of parts such as an inner ring, an outer ring, a rolling element, and a cage, the manufacturing cost tends to increase, and the storage space for the rolling element is required. There is a limit.

Therefore, from the viewpoint of cost reduction and downsizing, a sliding bearing may be used in place of the rolling bearing (see, for example, Patent Document 2 below).
JP 2004-183828 A JP 2002-059373 A

  By the way, conventional sliding bearings typically support a radial load generated on the shaft by slidingly supporting the outer peripheral surface of the shaft.

  Therefore, if a sliding bearing is used as a bearing that supports a shaft that receives thrust loads from two opposite directions, such as the rotating shaft of a motor that drives a worm gear mechanism, it can support radial loads but supports thrust loads accurately. It will be difficult to do. Therefore, it is necessary to dispose a bearing or the like separately to support the thrust load, resulting in an increase in the number of parts and a problem that the cost cannot be sufficiently reduced.

  An object of the present invention is to provide a slide bearing unit capable of supporting not only a radial load but also a thrust load from both directions at a low cost.

  The first means for solving the above problems is a sliding bearing unit, an inner member fixed to the outer peripheral surface of the shaft, and an outer member that accommodates the inner member in a relatively rotatable manner inside. A radial bearing portion that is formed between the outer peripheral surface of the inner member and the inner peripheral surface of the outer member that faces the outer peripheral surface in the radial direction and supports a radial load; and the axial direction of the inner member A first thrust bearing portion formed between one end surface and one end surface of the outer member facing the one end surface in the axial direction and capable of supporting a thrust load; and the other axial end surface of the inner member; The second thrust bearing portion is formed between the other end surface of the outer member facing the other end surface in the axial direction, and is capable of supporting a load opposite to the thrust load.

  According to this first means, in addition to supporting the radial load by the radial bearing portion formed on the outer peripheral side of the inner member, the thrust bearing portions respectively formed on the both axial ends of the inner member, It can support thrust loads in both opposite directions. In addition, a radial load and a thrust load in both directions can be easily supported between the outer peripheral surface of the single inner member and both end surfaces in the axial direction and the surface of the outer member facing each surface of the inner member. Since it is a simple structure, it is not necessary to arrange a separate bearing or the like to support the thrust load as in the case of a conventional sliding bearing, so that the number of parts and the number of assembly steps can be reduced.

  In the above configuration, a portion including at least one of the surfaces of the inner member and the outer member forming the radial bearing portion, the first thrust bearing portion, and the second thrust bearing portion is a lubricant. You may form with the sintered metal impregnated (for example, lubricating oil or lubricating grease).

  If it does in this way, with relative rotation of the inner member with respect to the outer member, the lubricant will ooze out from the inside of the sintered metal into at least one bearing portion. Therefore, the sliding state in the bearing portion supplied with the lubricant can be maintained satisfactorily.

  In the above configuration, it is preferable that an inner diameter of the inner member is smaller than a minimum inner diameter of the outer member.

  If it does in this way, it will become possible to insert and fix a rotating shaft, such as a motor, simply to the inner peripheral surface of the inner member housed inside the outer member by a method such as press fitting. Therefore, when the shaft of a motor or the like is actually supported by such a sliding bearing unit, the assembly work of the shaft is not forced, and it is practically advantageous.

  In the above configuration, the outer member has an outer surface having a surface forming the radial bearing portion, and a surface forming one of the first thrust bearing portion and the second thrust bearing portion. It is preferable that the member base is constituted by a member base and a thrust member having a surface fixed to the outer member base and forming the other thrust bearing portion.

  In this way, for example, after the inner member is inserted inside the outer member base, it is possible to fix the thrust member to the outer member base, and the inner member can be easily and inside the outer member. It can be reliably accommodated, and the assembly process can be simplified.

  The second means for solving the above problems is a sliding bearing unit, an inner member fixed to the outer peripheral surface of the shaft, and an outer member that accommodates the inner member in a relatively rotatable manner inside. A radial bearing portion that is formed between the outer peripheral surface of the shaft and the inner peripheral surface of the outer member facing the outer peripheral surface in the radial direction, and that supports a radial load; and one axial direction of the inner member. A first thrust bearing portion formed between an end face and one end face of the outer member facing the one end face in the axial direction and capable of supporting a thrust load; and the other axial end face of the inner member; A second thrust bearing portion formed between the other end surface and the other end surface of the outer member facing in the axial direction and capable of supporting a load in a direction opposite to the thrust load is provided.

  According to the second means, only the point that the radial load formed between the inner peripheral surface of the outer member and the outer peripheral surface of the shaft is supported is different from the above-described slide bearing unit. The point that the thrust bearings formed in the axial direction both ends of the inner member can support thrust loads in both directions opposite to each other is the same as the above-described sliding bearing unit. Therefore, it is possible to support radial loads and thrust thrusts in both directions with a simple structure similar to the above-described plain bearing unit. Therefore, a separate bearing or the like is required to support the thrust load like conventional slide bearings. There is no need to arrange them, and the number of parts and the number of assembly steps can be reduced.

  As described above, according to the slide bearing unit (first means) according to the present invention, the radial load is supported by the radial bearing portion formed on the outer peripheral side of the inner member, and the shaft of the inner member is also supported. Thrust bearings formed on both ends in the direction can support the thrust loads in both directions opposite to each other. Moreover, since it has a simple structure that can support radial loads and thrust loads in both directions between a single inner member and an outer member that accommodates the inner member, the number of parts and the number of assembly steps can be reduced. The cost can be reduced by reducing the cost.

  Further, according to the slide bearing unit (second means) according to the present invention, the radial load is supported by the radial bearing portion formed between the inner peripheral surface of the outer member and the outer peripheral surface of the shaft, Thrust bearing portions formed on both ends in the axial direction of the direction member can support thrust loads in both directions opposite to each other. Therefore, similar to the first means, the radial load and the thrust load in both directions can be supported with a simple structure, so that the number of parts and the number of assembly steps can be reduced and the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a plain bearing unit according to an embodiment of the present invention. As shown in the figure, the slide bearing unit 1 is composed of a thick cylindrical inner member 2 fixed to the outer peripheral surface of the shaft, and an outer member 3 that rotatably accommodates the inner member 2. Has been.

  The outer member 3 includes a thick cylindrical outer member base 4 having a large-diameter surface 4a and a small-diameter surface 4b that are continuous in the axial direction through a step (step-forming surface 4c) on the inner periphery, and the outer member. A thick annular thrust member 5 inserted and fixed to the large-diameter surface 4a of the base 4 is constituted. In this embodiment, an annular flange 6 projecting radially outward is provided on the outer peripheral portion of the outer member base 4, but the flange 6 can be omitted if necessary.

  The inner member 2 is inserted into the large-diameter surface 4a of the outer member base 4. The outer peripheral surface 2a is slidably supported by the large-diameter surface 4a of the outer member base 4, and the outer member 2 The axially opposite end surfaces 2b and 2c are slidably supported by the step forming surface 4c of the member base 4 and the axial one end surface 5a of the thrust member 5, respectively.

  In this state, a radial bearing portion 7 that supports a radial load is formed between the outer peripheral surface 2 a of the inner member 2 and the large-diameter surface 4 a of the outer member base 4. At the same time, when a thrust load in one direction is applied to the shaft, a thrust bearing is provided between the axial end surface 2b of the inner member 2 fixed to the shaft and the step forming surface 4c of the outer member base 4. Part 8 is formed. When a thrust load in the other direction is applied to the shaft, a thrust bearing portion 9 is formed between the axial end end surface 5a of the thrust member 5. Therefore, while supporting the radial load by the radial bearing portion 7 formed on the outer peripheral side of the inner member 2, the thrust bearing portions 8 and 9 respectively formed on both sides in the axial direction of the inner member 2 can be used in either direction opposite to each other. It is also possible to support the thrust load.

  The radial dimension L1 of the inner peripheral surface 2d of the inner member 2 is smaller than the radial dimension L2 of the large diameter surface 4a of the outer member base 4 and the radial dimension L3 of the inner peripheral surface 5b of the thrust member 5. Thus, the shaft can be inserted and fixed to the inner peripheral surface 2 b of the inner member 2.

  The material of the inner member 2 and the outer member base 4 is not particularly limited. For example, a sintered metal of copper-based, iron-based, or copper-iron-based material, or a lubricant or lubricant for the sintered metal. A sintered metal impregnated with a lubricant such as grease or a metal such as steel such as stainless steel can be used. When the inner member 2 is a rotating side member and the outer member base 4 is a fixed side member as in the present embodiment, the outer member base 4 is a sintered metal impregnated with a lubricant. It is preferable to form by. By doing so, the lubricant exudes efficiently from the outer member base 4 as the inner member 2 rotates, and the sliding characteristics of the radial bearing portion 7 can be maintained well. is there. The material of the thrust member 5 is not particularly limited, but for example, a sintered metal or a resin can be used.

  The slide bearing unit 1 is assembled by the following procedure, for example.

  First, the inner member 2 is inserted from the opening side of the large diameter surface 4 a of the outer member base 4 to the position of the step forming surface 4 c of the outer member base 4. In this state, the thrust member 5 is inserted and fixed to the large-diameter surface 4 a of the outer member base 4 to a predetermined position in the axial direction, and both axial end surfaces 2 b and 2 c of the inner member 2 are fixed to the outer member base 4. It is accommodated between the step forming surface 4c and the axial end surface 5a of the thrust member 5. As described above, the inner member 2 can be easily and reliably accommodated by the outer member base 4 and the thrust member 5 in the form of being covered with the thrust member 5. Here, the radial dimension of the outer peripheral surface 2a of the inner member 2 is slightly smaller than the radial dimension of the large diameter surface 4a of the outer member base 4, and the outer peripheral surface 2a of the inner member 2 A space corresponding to the above-described radial bearing portion 7 is formed between the large-diameter surface 4a of the member base 4. Further, the thrust member 5 is inserted and fixed to a position where spaces corresponding to the thrust bearing portions 8 and 9 described above are formed on both axial ends of the inner member 2. The thrust member 5 can be fixed by, for example, bonding, press-fitting, or a method using a combination of bonding and press-fitting, but from the viewpoint of simplifying the assembly process, it is preferable to perform the pressing.

  The sliding bearing unit 1 configured as described above is used by being incorporated in a worm gear mechanism 10 as shown in FIG.

  The worm gear mechanism 10 shown in FIG. 2 transmits torque from the worm gear 11 to the load side via the worm wheel 12 by meshing the worm gear 12 for torque transmission with the worm gear 11 on the driving side. The worm gear 11 is formed integrally with a shaft 14 that is rotationally driven by a motor 13, and a tip end portion of the shaft 14 is rotatably supported by the slide bearing unit 1. In the figure, reference numeral 15 denotes a housing, and 16 denotes a sliding bearing (sintered oil-impregnated bearing) that supports only the radial load generated on the shaft 14 at the base end portion of the shaft.

  More specifically, as shown in FIG. 3, the sliding bearing unit 1 is fixed in a state where the outer member base 4 is fitted to the housing 15 and is rotatably accommodated by the outer member base 4 and the thrust member 5. A shaft 14 is inserted and fixed to the inner peripheral surface 2 b of the inner member 2 formed. The shaft 14 can be fixed by, for example, bonding, press-fitting, or a method using a combination of bonding and press-fitting, but from the viewpoint of simplifying the assembly process, it is preferable to perform pressing. Further, the outer member base 4 is positioned in the axial direction by the flange portion 6.

  When the shaft 14 fixed to the inner peripheral surface of the inner member 2 is driven by the motor 13, the shaft 14 and the inner member 2 rotate together. At this time, a thrust load can act on the shaft 14 in directions opposite to each other when the motor 13 is rotated forward and when the motor 13 is driven reversely. However, when a thrust load in one direction acts on the shaft 14, For example, when the thrust bearing portion 8 supports the load and a thrust load in the other direction acts on the shaft, the load is supported by the thrust bearing portion 9 on the opposite side. Of course, the radial load generated on the shaft 14 is always supported by the radial bearing portion 7 formed on the outer peripheral side of the inner member 2.

  As described above, according to the sliding bearing unit 1 according to the present embodiment, the radial load is supported by the radial bearing portion 7 formed on the outer periphery of the inner member 2, and both axial ends of the inner member 2 are supported. Thrust bearing portions 8 and 9 formed on the sides can support thrust loads in both directions opposite to each other. Moreover, the radial load and the thrust load in both directions are supported between the single inner member 2 and the outer member 3 (the outer member base 4 and the thrust member 5) that accommodates the inner member 2. Since it has a simple structure, the number of parts and the number of assembling steps can be reduced and the cost can be reduced.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications are possible.

  In the above embodiment, the inner member is inserted into the large-diameter surface 4a of the outer member base 4, the axial end 2b of the inner member 2 is supported by the step forming surface 4c of the outer member base 4, and the inner In the above description, the other end surface 2c in the axial direction of the member 2 is supported by the thrust member 5. However, when the thrust load is large, for example, as shown in FIG. 4 and FIG. A thick annular thrust auxiliary member 17 inserted and fixed on the large-diameter surface 4a may be interposed therebetween. In this case, the thrust bearing portion 8 formed on the one axial end side of the inner member 2 is formed between the inner member 8 and the thrust auxiliary member 17. Further, it is important that the thrust auxiliary member 17 is made of a material that is more easily worn than the inner member 2 and the outer member base 4 and has good sliding characteristics between the inner member 2, such as a resin. It is. Further, when it is necessary to support a larger thrust load, the thrust member 5 may be screwed to the end surface of the outer member base 4 with screws 18 as shown in FIG.

  In the above embodiment, the radial bearing portion 7 is formed between the outer peripheral surface 2a of the inner member 2 and the large-diameter surface 4a of the outer member base 4. However, as shown in FIG. In addition, the radial bearing portion 7 may be formed between the small diameter surface 4 b of the outer member base 4 and the outer peripheral surface 14 a of the shaft 14. In this way, even if a certain amount of gap (a gap larger than that required for the radial bearing portion 7) is formed between the outer peripheral surface 2a of the inner member 2 and the large diameter surface 4a of the outer member base 4. Therefore, the required dimensional accuracy of the outer peripheral surface 2a can be reduced as compared with the case where the radial bearing portion 7 is formed by the outer peripheral surface 2a of the inner member 2. Therefore, the processing of the inner member 2 can be simplified. Such a configuration is suitable when the shaft 14 fixed to the inner member 2 is made of a material having excellent sliding characteristics with the outer member base 4 and the dimensions satisfy the desired dimensional accuracy. . The dimensional relationship between the outer peripheral surface 2 a of the inner member 2 and the large-diameter surface 4 a of the outer member base 4, and between the small-diameter surface 4 b of the outer member base 4 and the outer peripheral surface 14 a of the shaft 14. As long as the above dimensional relationship is satisfied, the configuration and various matters described in the above embodiment can be applied.

  In the above-described embodiment, the specific usage of the sliding bearing unit 1 has been described as a bearing that supports the shaft 14 of the motor that drives the worm gear mechanism 10. It can also be used as a rotating shaft of a motor used or other general rotating body support parts.

It is sectional drawing of the sliding bearing unit which concerns on embodiment of this invention. It is sectional drawing which shows the worm gear mechanism incorporating the plain bearing unit. It is sectional drawing which expands and shows the slide bearing unit periphery of FIG. It is sectional drawing which shows the other form of a sliding bearing unit. It is sectional drawing which shows the other form of a sliding bearing unit. It is sectional drawing which shows the other form of a sliding bearing unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sliding bearing unit 2 Inner member 3 Outer member 4 Outer member base | substrate 5 Thrust member 6 鍔 part 7 Radial bearing part 8, 9 Thrust bearing part 10 Worm gear mechanism 11 Worm gear 12 Worm wheel 13 Motor 14 Shaft 15 Housing

Claims (5)

An inner member fixed to the outer peripheral surface of the shaft;
An outer member that accommodates the inner member in a relatively rotatable manner inside;
A radial bearing that is formed between the outer peripheral surface of the inner member and the inner peripheral surface of the outer member facing the outer peripheral surface in the radial direction, and supports a radial load;
A first thrust bearing portion formed between one end surface in the axial direction of the inner member and one end surface of the outer member facing the one end surface in the axial direction, and capable of supporting a thrust load;
A second thrust bearing formed between the other axial end face of the inner member and the other end face of the outer member facing the other end face in the axial direction and capable of supporting a load opposite to the thrust load. And a plain bearing unit.   Of the surfaces forming the radial bearing portion, the first thrust bearing portion, and the second thrust bearing portion of the inner member and the outer member, a portion including at least one of the surfaces is impregnated with a lubricant. The sliding bearing unit according to claim 1, wherein the sliding bearing unit is formed of a sintered metal.   The sliding bearing unit according to claim 1 or 2, wherein an inner diameter of the inner member is smaller than a minimum inner diameter of the outer member.   The outer member base having a surface on which the outer member forms the radial bearing portion, and a surface on which one of the first thrust bearing portion and the second thrust bearing portion is formed; and The sliding bearing unit according to any one of claims 1 to 3, wherein the sliding bearing unit includes a thrust member that is separate from the outer member base and has a surface that forms the other thrust bearing portion. An inner member fixed to the outer peripheral surface of the shaft;
An outer member that accommodates the inner member in a relatively rotatable manner inside;
A radial bearing portion formed between the outer peripheral surface of the shaft and the inner peripheral surface of the outer member facing the outer peripheral surface in the radial direction, and supporting a radial load;
A first thrust bearing portion formed between one end surface in the axial direction of the inner member and one end surface of the outer member facing the one end surface in the axial direction, and capable of supporting a thrust load;
A second thrust bearing formed between the other axial end face of the inner member and the other end face of the outer member facing the other end face in the axial direction and capable of supporting a load opposite to the thrust load. And a plain bearing unit.

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