GB2487683A

GB2487683A - Bearing unit

Info

Publication number: GB2487683A
Application number: GB1206688.2A
Authority: GB
Inventors: Makoto Kanehira; Toshio Takahashi; Takashi Makino; Hiroki Ishida; Toshihiko Aoki
Original assignee: Tsubakimoto Chain Co
Current assignee: Tsubakimoto Chain Co
Priority date: 2009-11-25
Filing date: 2010-10-29
Publication date: 2012-08-01
Also published as: CN102597577A; WO2011065186A1; JP5340898B2; GB201206688D0; JP2011112120A; CN102597577B

Abstract

Provided is a bearing unit wherein the accuracy of teeth is ensured when the bearing unit is machined, the production time is reduced, the production cost is reduced, and the reduction of the accuracy of teeth due to unevenness of a material, machining strain, heat strain, etc., is suppressed, so that noise or uneven rotation generated during an operation is prevented, and the durability is improved. A bearing unit (100) comprises a cylindrical gear (110) having teeth (111) which mesh with another gear (150) and a flange (132) which constitutes a bearing, on the inner periphery and the outer periphery of the cylindrical gear. The cylindrical gear (110) is formed by stacking and affixing a plurality of gear modules (120, 130, 140) in the axial direction.

Description

DESCRIPTION

BEARING UNIT

Technical Field

[0001] The present invention relates to a bearing unit comprising a cylindrical gear having teeth engaging with another gear and a flange forming a bearing respectively on an inner circumference or an outer circumference thereof, and more specifically to a bearing unit suitably applicable to a rotary section of heavy machinery such as construction machineries and cranes.

Background Art

[0002] Hitherto, there has been known a bearing unit comprising a cylindrical gear having teeth engaging with another gear and a flange forming a bearing respectively on an inner circumference or an outer circumference thereof.

The known bearing unit is produced from one material by machining by a working machine such as a gear cutting machine (see Patent Document 1).

Prior Art Document

Patent Document [0003] Patent Document 1: Japanese Patent Application Laid-open No. 2005-61574 (Page 5, FIG. 2)

Disclosure of Invention

Problems to be Solved by the Invention [0004] However, because the known bearing unit is large and a length of teeth in an axial direction is long, the bearing unit has had such problems that it is difficult to assure precision of the teeth during machining, it takes a long time for its production and its production cost is very high.

Still more, because the precision of the teeth degrades also due to non-homogeneity of the material, strain caused during machining or strain caused in post-processing such as heat treatment, the bearing unit has had other problems that it causes noise and rotational unevenness during operation and its durability is low because it may be possibly worn and broken.

Summary of the Invent ion

[0005] The invention aims at solving the prior art problems described above by providing a bearing unit whose precision of teeth is assured during machining, whose production time is shortened, whose cost is reduced, whose noise and rotational unevenness during operation are prevented and whose durability is improved by suppressing degradation of the precision of the teeth otherwise caused by non-homogeneity of its material, processing strain and thermal strain.

Means for Solving the Problems [0006] In order to solve the above-mentioned problems, according to a first aspect of the invention, there is provided a bearing unit comprising a cylindrical gear having teeth engaging with another gear and a flange forming a bearing respectively on an inner circumference or an outer circumference thereof, wherein the cylindrical gear is formed by piling up and fixing a plurality of gear modules, each having teeth formed on the inner circumference or the outer circumference and engaging with the other gears, in a plurality of layers in an axial direction.

[0007] According to a second aspect of the invention, the above-mentioned problems are solved also by arranging such that the plurality of gear modules is split into a plurality of gear modules in a circumferential direction in all of the layers and the cylindrical gear is formed by piling up and fixing the plurality of gear modules in the axial direction while shifting phases of split positions, in addition to the arrangement of the bearing unit described in the first aspect.

[0008] According to a third aspect of the invention, the above-mentioned problems are solved by arranging further such that the cylindrical gear is formed by piling up and fixing the plurality of gear modules in the axial direction while shifting phases of teeth of the gear modules, in addition to the arrangement of the bearing unit described in the first or second aspect.

[0009] According to a fourth aspect of the invention, the above-mentioned problems are also solved by arranging such that the flange forming the bearing is formed on the outer circumference or the inner circumference of at least one layer of the gear modules in the axial direction among the plurality of gear modules, in addition to the arrangement of the bearing unit described in any one of the first through third aspects.

[0010] According to a fifth aspect of the invention, the above-mentioned problems are solved also by arranging such that the teeth of the gear modules have concave grooves at least at edges on the side adjoining with teeth of another gear module, in addition to the arrangement of the bearing unit described in any one of the first through fourth aspects.

[0011] According to a sixth aspect of the invention, the above-mentioned problems are also solved by arranging such that the gear modules are formed of a general gear material to which heat treatment is implemented, in addition to the arrangement of the bearing unit described in any one of the first through fifth aspects.

[0012] According to a seventh aspect of the invention, the above-mentioned problems are also solved by arranging such that the gear modules are formed of a wear-resistant steel plate, in addition to the arrangement of the bearing unit described in any one of the first through fifth aspects.

Advantages [0013] According to the first aspect of the invention, because the cylindrical gear is formed by piling up and fixing the plurality of gear modules, each having teeth formed on the inner circumference or the outer circumference and engaging with the other gears, in the plurality of layers in the axial direction in the bearing unit comprising the cylindrical gear and the flange forming the bearing, a length of teeth in the axial direction of each gear module can be shortened. Therefore, it becomes possible to assure precision of the teeth in machining, to shorten a production time and to lower a production cost.

[0014] Still more, because it becomes possible to replace per each gear modules, it becomes possible to replace and repair only broken or defective one of the gear modules and to lower a maintenance cost even when a part of the bearing unit is broken or becomes defective.

[0015] Furthermore, because each gear module can be small and thinned, it becomes possible to suppress degradation of the precision of the teeth due to non-homogeneity of its material, processing strain and thermal strain, to also prevent noise and rotational unevenness otherwise caused during operation and to improve its durability.

[OOlGJ According to the bearing unit of the second aspect of the invention, because the plurality of gear modules is split into the plurality of gear modules in the circumferential direction in all of the layers and the cylindrical gear is formed by piling up and fixing the plurality of gear modules in the axial direction while shifting the phases of the split positions, in addition to the effects brought about by the bearing unit of the first aspect, it becomes unnecessary to use a circumferential gear module and a fixing circumferential member. Accordingly, it becomes possible to lower the production cost further, to disperse split points in the circumferential direction, to prevent the noise and rotational unevenness during operation and to improve the durability further.

{0017] According to the bearing unit of the third aspect of the invention, because the cylindrical gear is formed by piling up and fixing the plurality of gear modules in the axial direction while shifting the phases of the teeth of the gear modules, in addition to the effects brought about by the bearing unit of the first or second aspect, it becomes possible to smooth an engagement with the other gear during operation, to prevent the noise and rotational unevenness during operation and to improve the durability.

[0018] According to the bearing unit of the fourth aspect of the invention, because the flange forming the bearing is formed on the outer circumference or the inner circumference of at least one layer of the gear modules in the axial direction among the plurality of gear modules, in addition to the effects brought about by the bearing unit of any one of the first through third aspects, it is just necessary to assure the flange having a thickness for forming the bearing.

Accordingly, the whole bearing unit can be downsized and parts to be machined are reduced, so that it becomes possible to shorten the production time further and to lower the production cost.

[0019] According to the bearing unit of the fifth aspect of the invention, because the teeth of the gear modules have the concave grooves at least at the edges on the side adjoining with teeth of another gear module, in addition to the effects brought about by the bearing unit of any one of the first through fourth aspects, the spaces for retaining lubricant oil can be provided at the middle parts in the axial direction of the gears. Therefore, it becomes possible to smooth the engagement with the other gear during operation, to prevent the noise and rotational unevenness during the operation and to improve the durability further.

[0020] According to the bearing unit of the sixth aspect of the invention, because the gear modules are formed of the general gear material to which heat treatment is implemented, in addition to the effects brought about by the bearing unit of any one of the first through fifth aspects, it becomes possible to shorten the production time, to lower the production cost and to prevent the noise and rotational unevenness otherwise caused during the operation without degrading the durability and the wear resistance.

[0021] According to the bearing unit of the seventh aspect of the invention, because the gear modules are formed of the wear-resistant steel plate, in addition to the effects brought about by the bearing unit of any one of the first through fifth aspects, it becomes easy to machine and requires no heat treatment. Therefore, it becomes possible to shorten the production time further, to lower the production cost and to prevent the noise and rotational unevenness otherwise caused during the operation.

Brief Description of Drawings

[0022] [FIG. 1] FIG. 1 is a perspective view of a bearing unit according to one embodiment of the invention.

[FIG. 2] FIG. 2 is a section view of the bearing unit of one embodiment of the invention.

[FIG. 3] FIG. 3 is a partially sectioned explanatory view of the bearing unit of one embodiment of the invention.

[FIG. 4] FIG. 4 is an enlarged view of a tooth of the bearing unit of one embodiment of the invention.

[FIG. 5] FIG. 5 is a section view of a facing part of teeth of the bearing unit of one embodiment of the invention.

[FIG. 6] FIG. 6 is a perspective view of a bearing unit according to another embodiment of the invention.

[FIG. 7] FIG. 7 is a section view of the bearing unit of the second embodiment of the invention.

Best Modes for Carrying Out the Invention [0023] A specific mode of the invention may be any mode as long as a bearing unit comprises a cylindrical gear having teeth and engaging with another gear and a flange fonning a bearing respectively on an inner circumference or an outer circumference thereof, wherein the cylindrical gear is formed by piling up and fixing a plurality of gear modules, each having teeth formed on the inner circumference or the outer circumference and engaging with the other gears, in a plurality of layers in an axial direction, and brings about the following features. That is, the invention allows precision of the teeth to be assured during machining, shortens a production time, lowers a production cost, suppresses degradation of the precision of the teeth otherwise caused by non-homogeneity of its material, processing strain and thermal strain, prevents noise and rotational unevenness during operation and improves durability of the bearing unit.

[0024] For instance, a number of gear modules of the bearing unit of the invention may be any number as long as it allows the precision of the teeth to be assured during machining, shortens the production time and lowers the production cost.

Still more, the plurality of gear modules can be fixed by any means such as bolts and nuts.

[First Embodiment] [0025J A bearing unit of one embodiment of the invention will be explained with reference to the drawings.

As shown in FIGs. 1 through 3, the bearing unit 100 of the first embodiment of the invention comprises a cylindrical gear 110 having teeth 111 engaging with another gear 150 on an inner circumferential side thereof and a flange 132 forming a bearing on an outer circumferential side thereof.

[0026] The cylindrical gear 110 is split into a plurality of gear modules 120, 130 and 140 in an axial direction (tooth-width direction) and a circumferential direction. The upper gear modules 120 forming an upper layer, the middle gear modules 130 forming a middle layer and the lower gear modules 140 forming a lower layer are fixed in a body by inserting bolts not shown through bolt holes 123, 133 and 143 provided through the respective gear modules 120, 130 and 140 while shifting phases of split positions thereof in the circumferential direction.

[0027] The flange 132 whose diameter is larger than those of the other gear modules 120 and 140 is provided on the outer circumferential side of the middle gear module 130. Then, the bearing is formed by abutting thrust bearings 101 above and under the flange 132 and by abutting a radial bearing 102 around an outer circumferential side of the flange 132.

[0028] Still more, as shown partly in FIGs. 4 and 5, concave grooves 124, 134 and 144 are provided respectively at upper edges of teeth 131 of the middle gear module 130 and of teeth 141 of the lower gear module 140 and at lower edges of teeth 121 of the upper gear module 120 and of the teeth 131 of the middle gear module 130.

[0029] Then, spaces are created by the concave grooves 124, 134 and 144 at boundary portions of the edges of the respective teeth 121, 131 and 141 when the upper, middle and lower gear modules 120, 130 and 140 are piled and fixed.

Lubricant oil is retained in the spaces.

[0030] According to the bearing unit 100 arranged as described above, it becomes possible to machine the teeth 121, 131 and 141 of the respective gear modules 120, 130 and by general machine tools and to foni them into a thickness less influenced by non-homogeneity of their material, processing strain and thennal strain.

Still more, the respective gear modules 120, 130 and 140 can be formed of an abrasion-resistant steel plate such as HARDOX (registered trademark), so that it becomes possible to eliminate heat treatment after machining.

[0031] Thereby, it becomes possible to assure precision of the teeth 111 during machining, to shorten a production time and to lower a production cost. Still more, because it becomes possible to suppress degradation of the precision of the teeth 111, it becomes also possible to prevent noise and rotational unevenness otherwise caused during operation and to improve durability of the teeth by suppressing wear and breakage thereof.

[0032] Still more, because it is possible to replace per each gear modules 120, 130 and 140, it becomes possible to replace and repair only broken or defective one of the gear modules 120, 130 and 140 and thus to lower a maintenance cost even when a part of the bearing unit is broken or becomes defective.

[00331 Still more, because the spaces formed by the concave grooves 124, 134 and 144 function as spaces for retaining the lubricant oil in intermediate sections in the axial direction of the whole teeth 111, the lubricant oil is smoothly supplied. Accordingly, it becomes possible to prevent noise during operation, to suppress wear and breakage of the teeth and to improve their durability.

[0034] Furthermore, because phases of the teeth 121, 131 and 141 of the respective gear modules 120, 130 and 140 can be shifted and the gear 150 having a tooth form corresponding to them can be engaged with them, it becomes possible to disperse engagement starting points of the teeth 121, 131 and l4l Thereby, it becomes possible to smooth the engagement with the other gear 150 during operation, to prevent the noise and rotational unevenness during operation and to improve the durability of the teeth by suppressing their wear and breakage further.

[Second Embodimentj [0035] As shown in FIGs. 6 and 7, a bearing unit 200 of another embodiment of the invention comprises a cylindrical gear 210 having teeth 211 formed on an outer circumferential side of the cylindrical gear 210 and engaging with another gear and a flange 232 forming a bearing on an inner circumferential side.

[0036] Similarly to the embodiment described above, the cylindrical gear 210 is split into a plurality of gear modules 120, 130 and 140 in axial (tooth width) and circumferential directions. The upper gear modules 220, the middle gear modules 230 and the lower gear modules 240 are fixed by inserting bolts not shown through bolt holes 223, 233 and 243 provided through the respective gear modules 220, 230 and 240 while shifting phases of split positions thereof in the circumferential direction. A flange 232 whose diameter is smaller than those of the other gear modules 220 and 240 is provided on the inner circumferential side of the middle gear module 230. Then, a bearing is formed by abutting thrust bearings 101 above and under the flange 232 and by abutting a radial bearing 102 around an inner circumferential side of the flange 232.

Industrial Applicability

[0037] As described above, according to the invention, it becomes possible to assure precision of the teeth during machining, to shorten the production time, to lower the production cost, to suppress the degradation of the precision of the teeth otherwise caused by the non-homogeneity of the material, processing strain and thermal strain, to prevent the noise and rotational unevenness otherwise caused during operation and to improve durability of the bearing unit. Thus, the advantageous effects of the invention are remarkable.

[0038) It is noted that although the three layers of the gear modules are provided in the axial direction and the flange forming the bearing is provided around the middle gear module in the embodiments described above, the number of layers of the gear modules may be two or four or more and the flange forming the bearing may be provided around any layers of the gear modules including the uppermost and lowermost layers of the gear modules.

[0039] The cylindrical gear can be also split into any number of gear modules in the circumferential direction as long as each gear module has a size that enables each gear module to be machined readily. The number of the split gear modules may be same or different in all of the layers.

Still more, it is possible to provide an either layer of the gear modules as a circumferential gear module without splitting in the circumferential direction and also to provide a fixing circumferential ring layer having no teeth.

Reference Numerals [0040] 100, 200 bearing unit 101 thrust bearing 102 radial bearing 110, 210 cylindrical gear 120, 220 upper gear module 121, 221 teeth 123, 222 bolt hole 130, 230 middle gear module 131, 231 teeth 132, 232 flange 133 bolt hole 134 concave groove 140, 240 lower gear module 141, 241 teeth 143 bolt hole 144 concave groove gear

Claims

CLAIMS1. A bearing unit (100) comprising a cylindrical gear (110) having teeth (111) engaging with another gear (150) and a flange (132) forming a bearing respectively formed on an inner circumference or an outer circumference thereof, characterized in that: said cylindrical gear (110) is formed by piling up and fixing a plurality of gear modules (120, 130, 140), each having teeth formed on the inner circumference or the outer circumference and engaging with the other gears (150), in a plurality of layers in an axial direction.
2. The bearing unit (100) according to Claim 1, characterized in that: said plurality of gear modules (120, 130, 140) is split into a plurality of gear modules in a circumferential direction in all of the layers and said cylindrical gear (110) is formed by piling up and fixing the plurality of gear modules (120, 130, 140) in the axial direction while shifting phases of split positions.
3. The bearing unit (100) according to Claim 1 or 2, characterized in that said cylindrical gear (110) is formed by piling up and fixing the plurality of gear modules (120, 130, 140) in the axial direction while shifting phases of teeth of the gear modules.
4. The bearing unit (100) according to any one of Claims 1 through 3, characterized in that the flange (132, 232)forming said bearing is formed on the outer circumference or the inner circumference of at least one layer of the gear modules (120, 130, 140) in the axial direction among said plurality of gear modules,
5. The bearing unit (100) according to any one of Claims 1 through 4, characterized in that the teeth of said gear modules (120, 130, 140) have concave grooves (144) at least at edges on the side adjoining with teeth of another gear module.
6. The bearing unit (100) according to any one of Claims 1 through 5, characterized in that said gear modules (120, 130, 140) are formed of a general gear material to which heat treatment is implemented.
7. The bearing unit (100) according to any one of Claims 1 through 5, characterized in that said gear modules (120, 130, 140) are formed of a wear-resistant steel plate.