JP2016148414A - Bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing unit with an excellent seal property.SOLUTION: In a bearing unit equipped with a shaft and a housing, the housing has a cylinder portion extending in an axial direction, and positioning on end portion in the axial direction on one end side in the axial direction than a shaft; a bottom portion extending inward in a diametrical direction from the one end portion in the axial direction of the cylinder portion; and a flange portion extending outward in the diametrical direction from the other end portion in the axial direction of the cylinder portion, and capable of being attached with a cultivation disc. The bearing has an inner ring, an outer ring, a plurality of rolling bodies, and a pair of seal members fixed to both end portions in the axial direction of an inner peripheral surface of the outer ring. On the other end side in the axial direction of the cylinder portion, an oil seal disposed near a bearing and between the housing and the shaft is provided. The oil seal has a core metal, an elastic member formed with at least one lip portion, and covered by the core metal, and a spring for fastening in the diametrical direction on the lip portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bearing unit.

  In agricultural applications, disk-type working machines are mainly used in field cropping when cultivating and seeding. Since the working machine including the tilling disk is dragged by a towing vehicle such as a tractor, the tilling disk rotates accordingly. At that time, the tilling disk can perform operations such as culling, formation of cocoons, and covering with soil after seeds and fertilizers are sown. Here, in order to support the rotation of the tilling disk, a rolling bearing such as a ball bearing or a tapered roller bearing, which is a combination of a bearing and a housing or unitized, is usually used for one disk.

  In addition, in order to perform work efficiently, a disk type farming machine uses several to several tens of disks in parallel per unit, so several to several tens of bearings are also used. . Moreover, since it is an outdoor (field) use fundamentally for an agricultural use and is a cultivation use, it is a severe use environment exposed to water, mud, sand, etc.

  As an example of the prior art, in the hub bearing assembly of Patent Document 1, a bearing and a housing having a flange portion are fitted to each other, and the flange portion and the disk are connected by a rivet. The hub shaft has a male thread portion on the outer peripheral surface at the tip, and the sleeve has a female thread portion on the inner peripheral surface. The hub shaft and the sleeve are screwed and fixed. The outer peripheral surface of the sleeve is in contact with the inner peripheral surface of the inner ring of the bearing.

  Moreover, as an example of the seal | sticker used for an agricultural use, the bearing seal of patent document 2 is mentioned. The bearing seal can be attached to the outer ring by an annular protrusion provided on the elastic member, and can be attached by snap action to a circumferential groove formed on the inner peripheral surface of the outer ring of the bearing.

Canadian National Publication No. 2561083 Japanese translation of PCT publication No. 2002-504653

  However, since the hub bearing assembly of Patent Document 1 has a complicated configuration, it takes time to attach and detach the work machine and the like, and the manufacturing cost increases.

  Further, the hub bearing assembly of Patent Document 1 has insufficient measures for sealing inside the bearing, and when mud, sand or the like enters the inside, it is fixed by the above-described male screw portion and female screw portion, and the bearing and disc are fixed. There is concern about the possibility of being unable to exchange.

  Further, in the seal of Patent Document 2, protection of the seal itself is not considered, and when it is damaged by mud or sand, there is a possibility that the sealing performance is lowered and a sufficient dustproof effect cannot be exhibited.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bearing unit that has a relatively simple structure, is easy to be detached, and has excellent sealing properties.

The above object of the present invention can be achieved by the following constitution.
(1) In a bearing unit comprising: an axis extending in the axial direction; and a housing disposed on the radially outer side of the shaft via a bearing,
The housing extends in the axial direction, and has a cylindrical portion whose one axial end is positioned on one axial end side of the shaft, a bottom extending radially inward from the axial one end of the cylindrical portion, and the cylindrical portion A flange portion that extends radially outward from the other axial end portion, and to which a cultivation disk can be attached,
The bearing includes an inner ring that fits outside the shaft, an outer ring that fits inside the cylindrical portion of the housing, a plurality of rolling elements disposed between the raceway surface of the inner ring and the raceway surface of the outer ring, and an axis of the inner peripheral surface of the outer ring. A pair of sealing members fixed to both ends in the direction,
An oil seal disposed between the housing and the shaft is provided in the vicinity of the bearing on the other axial end side of the cylindrical portion,
The oil seal includes a cored bar, an elastic member in which at least one lip part is formed and covered with the cored bar, and a spring for tightening the lip part in a radial direction.
(2) The axial movement of the oil seal is restricted by a retaining ring fitted in a retaining ring groove formed in the cylindrical portion of the housing.
(3) The oil seal is slidable with respect to the shaft via an inner ring spacer that contacts the bearing.

  According to the bearing unit of the present invention, the bearing is easily attached to and detached from the support arm and the like, the structure is simple, the bearing is sealed with a pair of seal members that block the inner and outer rings of the bearing, and in the vicinity of the axial direction of the bearing. Furthermore, since an oil seal is disposed between the housing and the shaft to form a double sealed structure, foreign matters such as mud and sand and water can be reliably prevented from entering the bearing.

It is sectional drawing of the bearing unit which concerns on embodiment. It is sectional drawing of a bearing. It is principal part sectional drawing of the bearing unit which enclosed grease.

  As shown in FIG. 1, the bearing unit 1 of the present embodiment includes a shaft 10 that extends in the axial direction, and a housing 30 that is disposed on the radially outer side of the shaft 10 via a bearing 20.

  The housing 30 extends in the axial direction, and has a cylindrical portion 31 in which one axial end portion (left end portion in FIG. 1) is positioned closer to one axial end side than the shaft 10, and one axial end portion of the cylindrical portion 31. A disc-shaped bottom 33 extending inward in the radial direction and an axially other end (the right end in FIG. 1) of the cylindrical portion 31 extend outward in the radial direction for agricultural purposes (eg, sowing seeds). And a flange portion 35 to which the used cultivation disk 3 can be attached. The housing 30 is made of an iron-based material, an aluminum-based material, or the like, and can be appropriately changed depending on use conditions.

  The flange portion 35 is provided with a plurality of bolt holes 35b penetrating in the axial direction while a disk mounting groove 35a is recessed in the other axial end portion. Thereby, when attaching / detaching the tilling disk 3 to / from the flange portion 35, the disk attachment groove 35a serves as a guide, and the attachment / detachment work can be facilitated. Further, when the outer diameter of the disk mounting groove 35a is Dh and the inner diameter of the tilling disk 3 is dh, if Dh <dh, interference between the tilling disk 3 and the housing 30 at the time of attachment / detachment is suppressed, and it is easy. Can work on. The annular tilling disc 3 attached to the disc attachment groove 35a is fastened and fixed to the flange portion 35 by bolts 36 screwed into the plurality of bolt holes 35b. The number of bolt holes 35b is preferably two or more, and preferably four or more, in order to prevent the tilling disk 3 from falling off the flange portion 35 by setting the tightening torque of the bolt 36 to be large. More preferred.

  The outer diameter of the bearing pillar portion 13 is set to be approximately equal to the inner diameter of the inner ring 21, and the inner ring 21 can be fitted onto the pillar portion 13. The fitting between the column portion 13 and the inner ring 21 is preferably a clearance fit. Further, a male screw portion 13a (fastening portion) is formed on the outer peripheral surface of the other end portion in the axial direction of the column portion 13 over the axial width M, and is screwed into the female screw portion 5a of the support arm 5 (support member). It is fixed. In addition, the fastening of the column part 13 and the support arm 5 is not restricted to the thing by the external thread part 13a and the internal thread part 5a, You may employ | adopt arbitrary methods.

  The support arm 5 includes an arm portion 5b that extends in the radial direction and a projection portion 5c that protrudes from the tip of the arm portion 5b toward one end in the axial direction. And the recessed part which has the internal thread part 5a is formed in the center of the protrusion part 5c so that the pillar part 13 of the axis | shaft 10 can be screwed together.

  As shown in FIG. 2, the bearing 20 is a double row ball bearing with a seal. More specifically, the bearing 20 includes an inner ring 21 that is externally fitted to the column portion 13 of the shaft 10, an outer ring 23 that is internally fitted to the cylindrical portion 31 of the housing 30, and the two rows of raceway surfaces 21 a and the outer ring 23. A plurality of balls 25 arranged between two rows of raceway surfaces 23a, a pair of seal members 27 fitted and fixed in seal grooves 23b provided at both axial ends of the inner peripheral surface of the outer ring 23; A pair of retainers 29 for holding the balls 25 in a row so as to be freely rollable.

  The seal member 27 is configured by covering a metal cored bar 27a with an elastic material 27b made of a rubber material or the like. The elastic member 27b is fitted and fixed in the seal groove 23b of the outer ring 23, and extends radially inward to slidably contact the outer peripheral surface of the inner ring 21 to ensure the sealing performance of the bearing 20. Depending on the usage conditions of the bearing 20, various rubber materials such as acrylic, nitrile, and fluorine meters are appropriately employed as the material of the elastic material 27b.

  Grease is sealed as a lubricant in the bearing 20, that is, in the space between the inner ring 21, the outer ring 23, and the pair of seal members 27. In order to enhance the lubrication effect of the bearing 20, it is preferable that the grease enclosure volume V (encapsulation amount) inside the bearing 20 is V ≧ 0.20 W, where W is the static space volume inside the bearing 20.

  The type of the bearing 20 is not particularly limited as long as it is a rolling bearing with a seal. For example, a single-row sealed ball bearing may be used, or two single-row sealed ball bearings may be combined. The bearing 20 may be an angular type double row or single row ball bearing or tapered roller bearing, or may be a combination of two such ball bearings or tapered roller bearings.

  As shown in FIG. 3, at the other axial end of the cylindrical portion 31, the inner ring spacer 7 fitted into the shaft 10 is in contact with the end surface of the inner ring 21 of the bearing 20, and the fixing position of the protruding portion 5 c of the support arm 5. And is slidable with the oil seal 4. Grease is applied between the inner ring spacer 7 and the oil seal 4 to reduce the frictional force during sliding.

  The oil seal 4 serves as a sealing device between the shaft 10 and the housing 30, and its axial movement is restricted by a retaining ring 6 fitted in a retaining ring groove 31 a formed in the cylindrical portion 31 of the housing 30. Has been. In the present embodiment, the curved cored bar 41 is in contact with the retaining ring 6.

  The oil seal 4 includes a cored bar 41, an elastic member 42 that is covered with the cored bar 41 and includes a main lip 42a and a sub lip 42b, and a garter spring 43 that is attached to the outer surfaces of the lips 42a and 42b. Lips 42 a and 42 b are fastened to the inner ring 21 in the radial direction by the garter spring 43.

  Even when the inner ring is eccentric due to the tightening force of the garter spring 43, the lips 42a and 42b can follow the inclination of the inner ring 21, and the followability of the lips 42a and 42b can be improved. In addition, even when foreign matters such as sand are caught in the lips 42a and 42b and the lips 42a and 42b are worn, the garter spring 43 gives a continuous tightening force to the lips 42a and 42b. Sealing performance can be maintained. In this embodiment, the garter spring 43 uses a spring wire, but other elastic materials may be formed into a coil shape.

  The inner space K of the oil seal 4 is filled with grease. When the space volume of the inner space K is W2 and the grease filling volume (filling amount) is V2, it is preferable that V2 ≧ 0.90W2.

  In this embodiment, by providing an oil seal in the vicinity of the bearing, it is possible to reduce the possibility of foreign matter and water from entering the seal member of the bearing, and to prevent foreign matter from entering the bearing. Therefore, the life of the bearing can be extended.

  In the oil seal of the present embodiment, the core metal 41 employs an iron material, but may be appropriately changed depending on the use conditions. The elastic member 42 is made of rubber. Depending on the use conditions, for example, various acrylic, fluorine, and nitrile rubber materials can be used.

1 Bearing unit 3 Plowing disk 5 Support arm (support member)
5a Female thread part 5b Arm part 5c Projection part 10 Shaft 11 Head part 11a Concave part 13 Column part 13a Male thread part (fastening part)
20 Bearing 21 Inner ring 21a Raceway surface 21b One end side surface 23 in the axial direction Outer ring 23a Raceway surface 23b Seal groove 25 Ball (rolling element)
27 Seal member 27a Core metal 27b Elastic material 29 Cage 30 Housing 31 Cylindrical part 31a Retaining ring groove 33 Bottom 35 Flange part 37 Cap member 4 Oil seal 41 Core metal 42 Elastic member 42a Main lip 42b Sub lip 6 Retaining ring 7 Between inner rings seat

Claims (3)

A shaft extending in the axial direction, and a housing disposed on a radially outer side of the shaft via a bearing;
In a bearing unit comprising:
The housing extends in the axial direction, and one end portion in the axial direction is positioned closer to one end side in the axial direction than the shaft, and a bottom portion extends radially inward from one end portion in the axial direction of the cylindrical portion; A flange portion that extends radially outward from the other axial end of the cylindrical portion, and to which a tillage disk can be attached;
The bearing includes an inner ring that is externally fitted to the shaft, an outer ring that is internally fitted to the cylindrical portion of the housing, a plurality of rolling elements disposed between a raceway surface of the inner ring and a raceway surface of the outer ring, A pair of seal members fixed to both axial ends of the inner peripheral surface of the outer ring,
On the other end side in the axial direction of the cylindrical portion, an oil seal disposed between the housing and the shaft is provided in the vicinity of the bearing,
The oil seal includes a metal core, an elastic member in which at least one lip portion is formed and covered with the metal core, and a spring for tightening the lip portion in a radial direction. .   2. The bearing unit according to claim 1, wherein the oil seal is restricted in its axial movement by a retaining ring fitted in a retaining ring groove formed in the cylindrical portion of the housing.   The oil seal is slidable with respect to the shaft via an inner ring spacer that contacts the bearing.

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