WO2023047650A1 - 波動歯車装置 - Google Patents
波動歯車装置 Download PDFInfo
- Publication number
- WO2023047650A1 WO2023047650A1 PCT/JP2022/011424 JP2022011424W WO2023047650A1 WO 2023047650 A1 WO2023047650 A1 WO 2023047650A1 JP 2022011424 W JP2022011424 W JP 2022011424W WO 2023047650 A1 WO2023047650 A1 WO 2023047650A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- outer ring
- bearing
- strain wave
- power transmission
- transmission efficiency
- Prior art date
Links
- 239000000463 material Substances 0.000 claims description 34
- 238000005096 rolling process Methods 0.000 claims description 23
- 239000011347 resin Substances 0.000 claims description 17
- 229920005989 resin Polymers 0.000 claims description 17
- 230000002093 peripheral effect Effects 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- 230000005540 biological transmission Effects 0.000 description 55
- 238000005452 bending Methods 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 11
- 239000004696 Poly ether ether ketone Substances 0.000 description 10
- 229920002530 polyetherether ketone Polymers 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 7
- 239000004810 polytetrafluoroethylene Substances 0.000 description 7
- 238000011156 evaluation Methods 0.000 description 6
- 229920006324 polyoxymethylene Polymers 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 229930040373 Paraformaldehyde Natural products 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- -1 polyoxymethylene Polymers 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 238000012937 correction Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 229910001092 metal group alloy Inorganic materials 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- 229910000861 Mg alloy Inorganic materials 0.000 description 3
- 229910001069 Ti alloy Inorganic materials 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 239000003638 chemical reducing agent Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 2
- 239000004734 Polyphenylene sulfide Substances 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 229920006351 engineering plastic Polymers 0.000 description 2
- 239000011151 fibre-reinforced plastic Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 229920000069 polyphenylene sulfide Polymers 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
- F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
- F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/58—Raceways; Race rings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
- F16H1/32—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear
Definitions
- the present invention relates to strain wave gearing.
- Strain wave gearing is characterized by high precision, high reduction ratio, and light weight. Therefore, the strain wave gearing is mainly used as a speed reducer for robots, but the power transmission efficiency of the strain wave gearing is lower than that of a general planetary gear.
- An object of the present invention is to provide a strain wave gearing that improves power transmission efficiency within a range that can withstand practical use.
- a strain wave gear device includes an internal gear, a flexible external gear, and a wave generator for generating a wave motion in the external gear.
- E Modulus of longitudinal elasticity
- I Moment of inertia of area
- D Outer diameter of outer ring
- the elasticity is 7.8 ⁇ 10 ⁇ 5 to 2.7 ⁇ 10 ⁇ 2 . According to the strain wave gearing of the present invention, the power transmission efficiency is improved within a practical range.
- the longitudinal elastic modulus E (GPa) of the outer ring is preferably 0.4-200. In this case, the power transmission efficiency is further improved while maintaining workability.
- the outer ring is preferably made of resin or light metal. In this case, power transmission efficiency is improved by a simple means of selecting materials.
- the outer ring is made of bearing steel, and the thickness ratio (%) of the thickness of the outer ring to the outer diameter of the outer ring is 1.2 to 2.1. is preferred. In this case, power transmission efficiency can be improved by a simple method of setting the thickness ratio within the above range while using an existing bearing material.
- the outer ring is supported by rolling elements, and at least one of the surface of the rolling element and the raceway surface of the rolling element in the outer ring or the inner ring has a A hard layer having a hardness higher than that of the substrate layer may be provided. In this case, power transmission efficiency is further improved.
- FIG. 1 is a diagram schematically showing a strain wave gearing according to a first embodiment of the present invention
- FIG. It is a figure which expands and shows the area
- FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2
- FIG. 6 is a strain wave gearing according to a second embodiment of the present invention, and is a diagram schematically showing a part of a bearing of the strain wave gearing.
- FIG. 10 is a strain wave gearing according to a third embodiment of the present invention, and is a diagram schematically showing a part of a bearing of the strain wave gearing.
- 4 is a line graph showing specific numerical results of power transmission efficiency obtained from Example 2 according to the present invention and specific numerical results of power transmission efficiency obtained from a comparative example with respect to Example 2; .
- reference numeral 1 is the strain wave gearing according to the first embodiment of the present invention.
- the wave gear device 1 has an internal gear 2 , a flexible (including elasticity) external gear 3 , and a wave generator 4 that causes the external gear 3 to generate wave motion.
- the wave generator 4 has an outer ring 6 a fitted to the inner peripheral surface of the external gear 3 .
- the wave generator 4 is assembled to the inner peripheral surface of the external gear 3 to deform the external gear 3 in a non-circular shape, thereby forming a meshing portion P with the internal gear 2 in the external gear 3 and The meshing portion P is moved in the circumferential direction of the internal gear 2.
- the internal gear 2 has a plurality of internal teeth 2a and an annular main body 2b.
- the plurality of internal teeth 2a protrude radially inward from the inner circumference of the annular main body 2b.
- the internal gear 2 is fixed to, for example, a housing (not shown) of the strain wave gearing 1 . That is, in this embodiment, the internal gear 2 is a fixed gear. Furthermore, in this embodiment, the internal gear 2 is a rigid gear with high rigidity.
- the internal gear 2 is made of, for example, iron-based materials such as cast iron, alloy steel, and carbon steel, light metal alloys such as magnesium alloys, aluminum alloys, and titanium alloys, or single light metals, PEEK (polyetheretherketone), and PPS (polyphenylene sulfide). , POM (polyoxymethylene) and other engineering plastics.
- iron-based materials such as cast iron, alloy steel, and carbon steel
- light metal alloys such as magnesium alloys, aluminum alloys, and titanium alloys, or single light metals
- PEEK polyetheretherketone
- PPS polyphenylene sulfide
- POM polyoxymethylene
- the external gear 3 has a plurality of external teeth 3a and an annular main body 3b.
- the plurality of external teeth 3a protrude radially outward from the outer circumference of the annular main body 3b.
- the external gear 3 is a flexible gear having flexibility.
- the external gear 3 can be mechanically deformed and restored, for example, by forming the annular main body 3b thin.
- the material for forming the external gear 3 can be metal or resin material, for example.
- the external gear 3 is made of, for example, a flexible material (for example, a thin material made of alloy steel, carbon steel, light metal, or a flexible resin material such as engineering plastic). can be transformed and restored.
- the wave generator 4 includes a wave generation core 5 and bearings 6 .
- the wave generation core 5 is connected to the drive shaft 7 .
- the drive shaft 7 is connected to a power source such as a motor (not shown).
- the wave generation core 5 is a member having high rigidity, like the internal gear 2 .
- the outer peripheral surface of the wave generating core 5 functions like a cam, for example.
- the rotation axis of the drive shaft 7 is coaxial with the axis O of the strain wave gearing 1 . This allows the wave-generating core 5 to rotate around the axis O.
- the wave-generating core 5 has a non-circular shape.
- the wave-generating core 5 is of the two-lobe type. As shown in FIG.
- the two-lobe shape has an elliptical shape when viewed from the axial direction (a line of sight from the direction of the axis O).
- reference numeral 5a denotes the vertex of the wave generating core 5 on the long axis side.
- the vertex 5a on the long axis side is arranged on the long axis.
- the bearing 6 allows relative rotation between the external gear 3 and the wave motion generating core 5 .
- the bearing 6 has an outer ring 6a, an inner ring 6b and rolling elements 6c.
- bearings having such a configuration include rolling bearings such as roller bearings and ball bearings (for example, deep groove ball bearings).
- the outer ring 6a and the inner ring 6b are flexible. Thereby, the outer ring 6a and the inner ring 6b can be deformed according to the contour shape of the wave generating core 5, respectively.
- the bearing 6 can be made of, for example, a resin material such as PTFE (polytetrafluoroethylene), PEEK (polyetheretherketone), POM (polyoxymethylene), or fiber-reinforced plastic. again.
- the bearing 6 can be made of, for example, a light metal alloy such as a titanium alloy, an aluminum alloy, a magnesium alloy, or a single light metal.
- the inner ring 6b of the bearing 6 is attached to the outer peripheral surface of the wave generating core 5.
- the bearing 6 is assembled to the wave generating core 5 so that the shape of the bearing 6 becomes the contour shape of the wave generating core 5 .
- the inner ring 6b can be formed integrally with the wave generating core 5. FIG. That is, according to the present invention, the inner ring 6b can be constructed as part of the wave-generating core 5 .
- the outer ring 6a of the bearing 6 is attached to the inner peripheral surface of the external gear 3.
- the outer ring 6a has flexibility.
- the bearing 6 can support the flexible external gear 3 so that the shape of the external gear 3 conforms to the contour shape of the wave generating core 5 .
- the wave-generating core 5 is two-lobed. Therefore, as shown in FIG. 1 , the external gear 3 bends in an elliptical shape along with the bearing 6 according to the shape of the wave generating core 5 .
- meshing portions P between the internal gear 2 and the external gear 3 are formed at two positions on the long axis side of the wave generating core 5 between the internal gear 2 and the external gear 3. be done.
- the wave gear device 1 when the wave generator 4 is rotated, the wave generating core 5 of the wave generator 4 can be rotated relative to the external gear 3 .
- the strain wave gearing 1 there is a tooth number difference between the number of teeth ZF of the external teeth 3a of the external gear 3 and the number of teeth ZR of the internal teeth 2a of the internal gear 2. Therefore, when the wave generator 4 is rotated, relative rotation occurs between the internal gear 2 and the external gear 3 due to the difference in the number of teeth.
- the meshing portion P of the external gear 3 moves in the circumferential direction of the internal gear 2 in a direction opposite to the rotational direction of the wave generator 4 .
- the meshing portion P moves relative to the internal gear 2 in a direction opposite to the direction of rotation of the wave generator 4 each time the wave generating core 5 rotates about the axis O by 180 degrees. That is, in this embodiment, the input rotation from the wave generator 4 is inverted and output as the reduced speed rotation from the external gear 3 .
- the strain wave gearing 1 decelerates by meshing the external teeth 3a of the external gear 3 and the internal teeth 2a of the internal gear 2 at two meshing portions P on the long axis side. Since the speed reduction ratio at this time is determined by the number of teeth of the external teeth 3a and the internal teeth 2a, it is possible to realize a high speed reduction ratio compared to other speed reducers.
- the strain wave gearing 1 is used, for example, as a speed reducer for a robot.
- the power transmission efficiency of conventional strain wave gearing is lower than that of general planetary gearing.
- the main reason for this is the frictional resistance, viscous resistance and agitation resistance in the bearing 6 in the wave generator 4 .
- the frictional resistance depends on, for example, the normal force N and the coefficient of dynamic friction ⁇ received at the sliding portion between the outer ring 6a and the rolling element 6c. Frictional resistance is relatively large in a mechanism such as a strain wave gearing in which a large vertical force is generated at the long shaft of the cam. Therefore, the conventional strain wave gearing inevitably suffers a large loss in power transmission efficiency.
- the present invention aims to reduce the frictional force F generated inside the bearing 6 and improve the power transmission efficiency in the wave gear device 1 .
- the frictional force F(N) is proportional to the normal force N.
- the wave generator 4 is of two-lobe type.
- the normal force N is the reaction force required to deform the perfectly circular bearing 6 into an elliptical shape according to the outer peripheral shape of the wave generating core 5 . Therefore, the normal force N becomes smaller as the bearing 6 becomes more deformable.
- the outer ring 6a has elasticity determined by the following formula (1).
- Elasticity (N/mm 2 ) E ⁇ I ⁇ (1/D 4 ) (1)
- I Moment of inertia of area
- D Outer diameter of outer ring 6a It is the diameter of the outer ring 6a at a certain time.
- said elasticity (N/mm 2 ) is in the range of 7.8 ⁇ 10 ⁇ 5 to 2.7 ⁇ 10 ⁇ 2 . More preferably, the elasticity (N/mm 2 ) is in the range of 7.8 ⁇ 10 ⁇ 5 to 5.9 ⁇ 10 ⁇ 4 , as will be apparent from the examples below.
- E ⁇ I represents bending rigidity (N ⁇ mm 2 ) and is also called bending rigidity EI.
- the bending stiffness EI is the product of the modulus of longitudinal elasticity E and the moment of inertia I.
- the term (1/D 4 ) multiplied by the bending stiffness EI is a correction term based on the outer diameter D of the bearing 6 .
- This correction term is a correction term for equalizing the difference in size of the strain wave gearing. Specifically, if the size of the strain wave gearing is changed, the thickness (t) and width (w) of the bearing are also changed accordingly. Therefore, the moment of inertia of area also changes greatly according to changes in the thickness (t) and width (w) of the bearing 6 .
- a correction term based on the outer diameter D of the outer ring 6a is used for leveling.
- the flexural rigidity EI of the outer ring 6a of the bearing 6 is reduced to the limit where the strength required for the strain wave gearing 1 can be secured, the force required to elastically deform the bearing 6 can be reduced within a practically durable range. be. As a result, the frictional force F generated between the outer ring 6a and the rolling elements 6c of the bearing 6 is also reduced within a range that can withstand practical use. As a result, reduction in the power transmission efficiency of the strain wave gearing 1 can be suppressed.
- the bending rigidity EI is set so that the elasticity (N/mm 2 ) satisfies the range of 7.8 ⁇ 10 ⁇ 5 to 2.7 ⁇ 10 ⁇ 2 .
- the power transmission efficiency is improved compared to the conventional strain wave gearing having no configuration according to the present invention.
- the elasticity (N/mm 2 ) is 7.8 ⁇ 10 ⁇ 5 or more, it is possible to improve power transmission efficiency while maintaining durability and workability.
- the bending rigidity EI of the outer ring 6a can be reduced to a range that can withstand practical use. can be reduced to the limit where the required strength can be secured.
- the bearing 6 is easily deformed within a range that can withstand practical use. improves.
- the longitudinal elastic modulus E (GPa) of the outer ring 6a is preferably in the range of 0.4-200.
- the modulus of longitudinal elasticity E (GPa) is 200 or less, the power transmission efficiency is further improved as compared with the conventional strain wave gearing that does not have the configuration according to the present invention.
- the modulus of longitudinal elasticity E (GPa) is 0.4 or more, the outer ring 6a of the bearing 6 can obtain rigidity that can support the external gear 3 in a more stable state. This improves power transmission efficiency.
- the workability of the outer ring 6a can also maintain the conventional workability. Therefore, if the longitudinal elastic modulus E (GPa) of the outer ring 6a is in the range of 0.4 to 200, the power transmission efficiency is further improved while maintaining workability.
- the outer ring 6a is preferably made of resin or light metal.
- the resin include resin materials such as PEEK (polyetheretherketone), POM (polyoxymethylene), PTFE (polytetrafluoroethylene), and fiber-reinforced plastics.
- the light metal may be, for example, a light metal alloy such as a titanium alloy, an aluminum alloy, a magnesium alloy, or a single light metal.
- the constituent material of the outer ring 6a does not have to be a single material.
- the material of the outer ring 6a can be a combination of resin and light metal.
- the constituent material of the outer ring 6a may be a combination of at least any two of resin, light metal and iron material.
- the inner ring 6b can be made of the same material as the outer ring 6a.
- the outer ring 6a is made of bearing steel (for example, SUJ2), and the thickness ratio (%), which is the ratio of the thickness t of the outer ring 6a to the outer diameter D of the outer ring 6a, is , 1.2 to 2.1.
- the thickness ratio (%) of the outer ring 6a is set within the range (1.2 to 2.1) while using the existing bearing material of bearing steel. .1) can improve power transmission efficiency.
- the frictional force F(N) is also proportional to the dynamic friction coefficient ⁇ .
- the coefficient of dynamic friction ⁇ generally decreases as the hardness of the sliding surface increases. Therefore, by forming a hard layer on the sliding surface between the rolling elements 6c and the outer ring 6a, the dynamic friction coefficient ⁇ can be reduced, and the reduction in the power transmission efficiency of the strain wave gearing 1 can be further suppressed.
- the outer ring 6a is supported by the rolling elements 6c. Therefore, in the present embodiment, at least one of the surface of the rolling element 6c and the raceway surface of the rolling element 6c in the outer ring 6a or the inner ring 6b is provided with a hard layer having higher hardness than the base material layer of the outer ring 6a. , the power transmission efficiency is further improved.
- the raceway surface of the rolling element 6c refers to at least one of the inner peripheral surface of the outer ring 6a and the outer peripheral surface of the inner ring 6b.
- the material used for the hard layer is, for example, a material having hardness higher than that of bearing steel, and a specific example is DLC (diamond-like carbon).
- the surface hardening treatment is not limited to a specific surface treatment. Examples of such surface effect treatments include chromium plating, nitriding, and carburizing.
- the hard layer can be formed on either the rolling element 6c or the raceway surface of the rolling element 6c. Alternatively, the hard layer can be formed on both the rolling elements 6c and the raceway surfaces of the rolling elements 6c. In this case, power transmission efficiency is most improved.
- the outer ring 6a can be made of a multi-layered structure
- the inner layer having the raceway grooves can be made of a hard layer such as iron
- the outer layer can be made of a material having a low longitudinal elastic modulus E such as resin.
- the inner ring 6b can be made of multiple layers, the outer layer as a raceway surface can be made of a hard layer such as iron, and the inner layer can be made of a material having a low longitudinal elastic modulus E such as resin.
- FIG. 4 is a strain wave gearing according to a second embodiment of the present invention, and is a diagram schematically showing part of the bearing 6 of the strain wave gearing.
- the shape of the outer ring 6a of the bearing 6 is changed.
- the outer peripheral surface of the outer ring 6a is provided with a plurality of grooves 6d spaced apart in the circumferential direction. If the groove 6d is provided in the outer ring 6a, the outer ring 6a can be easily bent starting from the groove 6d. That is, the bending rigidity EI of the outer ring 6a can be reduced by providing the groove 6d in the outer ring 6a. This makes it easier to bend the outer ring 6a. Therefore, according to this embodiment, the power transmission efficiency can be improved as compared with a wave gear device without the groove 6d.
- the groove 6d is formed as a groove recessed radially inward toward the axis O. Further, in this embodiment, the groove 6d extends parallel to the axis O, that is, parallel to the axial direction. Furthermore, in this embodiment, the groove 6d is a long groove formed to reach the axial end of the outer ring 6a. Further, referring to FIG. 4, the power transmission efficiency can be improved by processing the outer ring 6a of the bearing 6 so that the degree of elasticity is within the above range. For example, by providing a V-shaped (wedge-shaped) long groove or a U-shaped long groove in the outer ring 6a of the bearing 6, the elasticity can be set within the above range.
- FIG. 5 is a strain wave gearing according to a third embodiment of the present invention, and is a diagram schematically showing part of the bearing 6 of the strain wave gearing.
- a hole portion B6 is provided inside the outer ring 6a.
- the hole B6 is a closed space inside the outer ring 6a. If the hole portion B6 is provided inside the outer ring 6a, a hole (space) is formed inside the outer ring 6a, so the longitudinal coefficient E is lowered. As a result, the bending stiffness EI can be lowered equivalently to the embodiment of FIG. This makes it easier to bend the outer ring 6a. Therefore, according to this embodiment, it is possible to improve the transmission efficiency as compared with a strain wave gearing having no air holes.
- the holes B6 are simply holes, but the holes B6 may be impregnated with a material having a low longitudinal elastic modulus E such as resin. Moreover, when the size of the pores is large, the pores become starting points of fatigue fracture. For this reason, it is desirable that the size of the pores (specifically, the average pore diameter, that is, the average diameter of the pores) is evenly dispersed at several tens of ⁇ m or less.
- Table 1 below shows the power transmission efficiency measurement results.
- the measurement results include the power transmission efficiency measurement results obtained in Examples 1 to 6 according to the present invention, and the power transmission efficiency obtained in Comparative Examples 1 to 2 for comparison with Examples 1 to 6. and the measurement results of
- Table 1 shows the elasticity of the outer ring 6a (N/mm 2 ), the thickness t (mm) of the outer ring 6a, the thickness ratio (%) of the outer ring 6a, and the outer ring 6a of the bearing 6 for each example and comparative example. are also shown.
- the power transmission efficiency is measured using the wave generator 4 as an input.
- the input rotation speed (rpm) was set to three types of 100 rpm, 500 rpm, and 1000 rpm in the range of 100 to 1000 rpm.
- the load torque (N ⁇ m) was measured at 1.0.
- Example 6 a hard layer made of DLC is formed on the rolling elements 6c, the raceway surface (inner peripheral surface) of the outer ring 6a, and the raceway surface (outer peripheral surface) of the inner ring 6b of the bearing 6.
- power transmission efficiency There are four types of power transmission efficiency: ⁇ : power transmission efficiency of 50% or more, ⁇ : power transmission efficiency of 40% or more and less than 50%, ⁇ : power transmission efficiency of 30% or more and less than 40%, ⁇ : power transmission efficiency of less than 30%. evaluated with
- Table 2 below shows the comprehensive judgment results of Examples 1 to 6 and Comparative Examples 1 and 2, taking practicality into account.
- Items for comprehensive evaluation include power transmission efficiency, processing difficulty, and durability.
- the overall evaluation is an evaluation that takes into consideration the power transmission efficiency, the difficulty of processing, and the durability.
- Comprehensive evaluation was made into 4 types of ⁇ : very good, ⁇ : good, ⁇ : slightly good, and ⁇ : bad. In this comprehensive evaluation, it was determined that a strain wave gearing device with a comprehensive evaluation of ⁇ or higher was practical.
- Example 1 is an example corresponding to the invention according to claim 3 of this application.
- the resin material is the same PTFE, and the thickness of the outer ring 6a and the inner ring 6b is 0.5 mm. In both cases, the bending rigidity is reduced by reducing the longitudinal elastic modulus E and the thickness of the outer ring 6a by changing the material, and good power transmission efficiency can be obtained. is too thin, has problems with durability, and cannot withstand practical use.
- Example 2 is also an example corresponding to the invention according to claim 3 of this application.
- Table 3 shows specific numerical results obtained by measuring the power transmission efficiency of Example 2.
- the power transmission efficiency of Example 2 was 50% or more, whereas the conventional technology
- the power transmission efficiency of the technology is about 22 to 30%, and we were able to confirm an improvement in power transmission efficiency of about two times.
- the thickness ratio (%) is preferably 2.4% to 4.4%. If the thickness ratio (%) is less than 2.4%, the thickness of the outer ring 6a including the inner ring 6b becomes too thin, and a sufficient raceway groove depth cannot be secured. In this case, there is concern that the rolling elements 6c may come off.
- the thickness ratio (%) is more than 4.4%, the thickness t of the outer ring 6a becomes too thick, and the elasticity (N/mm 2 ) becomes too large. , the power transmission efficiency deteriorates. Therefore, when the material of the outer ring 6a of the bearing 6 is PEEK, the thickness ratio (%) is preferably 2.4% to 4.4%.
- PEEK was used as the resin material for the outer ring 6a and the inner ring 6b.
- a light metal alloy or a light metal simple substance may be used, and the longitudinal elastic modulus E is desirably in the range of 0.4 GPa to 200 GPa.
- Examples 3 to 5 are examples corresponding to the invention according to claim 4 of this application.
- the outer ring 6a and the inner ring 6b of the bearing 6 were made of bearing steel (SUJ2), and the thickness ratio (%) was changed from 2.4% in Comparative Example 1 to 2.1%, 1.5%, and 1.2%, respectively.
- the thickness ratio (%) is preferably 1.2% to 2.1%. If the thickness ratio (%) is less than 1.2%, the outer ring 6a and the inner ring 6b are too thin.
- the thickness ratio (%) is more than 2.1%, the thickness is almost the same as in Comparative Example 1 and becomes too thick, so the elasticity (N/mm 2 ) becomes too large. As a result, power transmission efficiency is not improved. Therefore, if the thickness ratio (%) is 2.1% or less, the reduction in transmission efficiency loss due to changes in thickness is reduced, and the power transmission efficiency is not significantly improved. Therefore, the thickness ratio (%) is more preferably 1.2% to 2.1%.
- the elastic degree (N/mm 2 ) of the strain wave gearing 1 is 7.8 ⁇ 10 ⁇ 5 to 2.7 ⁇ 10 ⁇ 5 .
- the range of 10 ⁇ 2 is satisfied, and it is clear that the power transmission efficiency is improved within a range that can withstand practical use. More preferably, as in Examples 1, 2 and 4, said elasticity (N/mm 2 ) ranges from 7.8 ⁇ 10 ⁇ 5 to 1.0 ⁇ 10 ⁇ 2 .
- one method of suppressing the bending rigidity EI is to change the material forming the outer ring 6a to a material having a low longitudinal elastic modulus E.
- the second method of suppressing the bending rigidity EI is to reduce the thickness t of the outer ring 6a.
- the outer ring 6a of the bearing 6 is shown in the AA section of FIG.
- the symbol w is the axial width of the outer ring 6a.
- symbol t is the thickness of the outer ring 6a.
- the geometrical moment of inertia I can be reduced by changing the cross-sectional shape and internal structure of the outer ring 6a.
- Specific examples include the above second and third embodiments.
- Example 6 is an example corresponding to the invention according to claim 5 of this application.
- a hard layer made of DLC is formed on the rolling elements 6c, the sliding surface (inner peripheral surface) of the outer ring 6a, and the sliding surface (outer peripheral surface) of the inner ring 6b. It can be seen that this suppresses the dynamic friction coefficient of the sliding portion, which contributes to the frictional force F, thereby improving the power transmission efficiency.
- DLC is described as the hard layer in the present embodiment, as described above, the hard layer is not limited to DLC. good.
- the strain wave gearing 1 has been described as a two-lobe type, but the present invention is different. It is not limited to a two-lobe shape.
- the wave-generating core 5 may be multi-lobed. Specific examples of the wave generating core 5 include, for example, a triangular three-lobe shape and a quadrilateral four-lobe shape.
- the power transmission path of the strain wave gearing device 1 has the wave generator 4 as an input and the external gear 3 as an output, but is not limited to this.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Retarders (AREA)
- Rolling Contact Bearings (AREA)
Abstract
Description
前記軸受の外輪は、以下の式(1)で求められる弾性度を有しており、
弾性度(N/mm2)=E×I×(1/D4)・・・(1)
E:縦弾性係数,I:断面二次モーメント,D:外輪の外径
さらに、前記弾性度は、7.8×10-5~2.7×10-2である。本発明の波動歯車装置によれば、実用に耐え得る範囲内で動力伝達効率が向上する。
弾性度(N/mm2)=E×I×(1/D4)・・・(1)
E:縦弾性係数,I:断面二次モーメント,D:外輪6aの外径
ここで、外輪6aの外径Dは、軸受6を波動生成コア5に取り付ける前の、軸受6が真円状態であるときの、外輪6aの直径である。
厚さ率(%)=t/D・・・(2)
D:外輪6aの外径、t:外輪6aの厚さ
Claims (5)
- 内歯歯車と、可撓性を有する外歯歯車と、前記外歯歯車に波動運動を生じさせる波動発生器と、を有しており、前記波動発生器は、前記外歯歯車の内周面に嵌合する軸受を有している、波動歯車装置であって、
前記軸受の外輪は、以下の式(1)で求められる弾性度を有しており、
弾性度(N/mm2)=E×I×(1/D4)・・・(1)
E:縦弾性係数,I:断面二次モーメント,D:外輪の外径
さらに、前記弾性度は、7.8×10-5~2.7×10-2である、波動歯車装置。 - 前記外輪の縦弾性係数E(GPa)は、0.4~200である、請求項1に記載された波動歯車装置。
- 前記外輪は、樹脂または軽金属によって形成されている、請求項2に記載された波動歯車装置。
- 前記外輪は、軸受鋼によって形成されており、前記外輪の外径に対する当該外輪の厚さの比である厚さ率(%)は、1.2~2.1である、請求項1に記載された波動歯車装置。
- 前記外輪は、転動体によって支持されており、前記転動体の表面と前記外輪または前記内輪における当該転動体の軌道面との少なくともいずれか一方に、前記外輪の基材層よりも硬度の高い硬質層が設けられている、請求項1~4のいずれか1項に記載された波動歯車装置。
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020247001884A KR20240023142A (ko) | 2021-09-24 | 2022-03-14 | 파동 기어 장치 |
CN202280062396.5A CN117980629A (zh) | 2021-09-24 | 2022-03-14 | 谐波齿轮装置 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2021-156175 | 2021-09-24 | ||
JP2021156175A JP7163466B1 (ja) | 2021-09-24 | 2021-09-24 | 波動歯車装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2023047650A1 true WO2023047650A1 (ja) | 2023-03-30 |
Family
ID=83845918
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2022/011424 WO2023047650A1 (ja) | 2021-09-24 | 2022-03-14 | 波動歯車装置 |
Country Status (4)
Country | Link |
---|---|
JP (1) | JP7163466B1 (ja) |
KR (1) | KR20240023142A (ja) |
CN (1) | CN117980629A (ja) |
WO (1) | WO2023047650A1 (ja) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2024068308A (ja) * | 2022-11-08 | 2024-05-20 | Ntn株式会社 | 転がり軸受 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018168955A (ja) * | 2017-03-30 | 2018-11-01 | セイコーエプソン株式会社 | ロボットおよび歯車装置 |
WO2019049295A1 (ja) * | 2017-09-07 | 2019-03-14 | 株式会社ハーモニック・ドライブ・システムズ | 波動発生器および波動歯車装置 |
JP2020026834A (ja) * | 2018-08-10 | 2020-02-20 | 日立オートモティブシステムズ株式会社 | 波動歯車減速機、及び内燃機関用リンク機構のアクチュエータ |
-
2021
- 2021-09-24 JP JP2021156175A patent/JP7163466B1/ja active Active
-
2022
- 2022-03-14 WO PCT/JP2022/011424 patent/WO2023047650A1/ja active Application Filing
- 2022-03-14 KR KR1020247001884A patent/KR20240023142A/ko unknown
- 2022-03-14 CN CN202280062396.5A patent/CN117980629A/zh active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018168955A (ja) * | 2017-03-30 | 2018-11-01 | セイコーエプソン株式会社 | ロボットおよび歯車装置 |
WO2019049295A1 (ja) * | 2017-09-07 | 2019-03-14 | 株式会社ハーモニック・ドライブ・システムズ | 波動発生器および波動歯車装置 |
JP2020026834A (ja) * | 2018-08-10 | 2020-02-20 | 日立オートモティブシステムズ株式会社 | 波動歯車減速機、及び内燃機関用リンク機構のアクチュエータ |
Also Published As
Publication number | Publication date |
---|---|
CN117980629A (zh) | 2024-05-03 |
JP7163466B1 (ja) | 2022-10-31 |
KR20240023142A (ko) | 2024-02-20 |
JP2023047216A (ja) | 2023-04-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6615689B2 (en) | Non-lubricated wave gear device | |
JP2007303592A (ja) | 波動歯車装置 | |
KR102189370B1 (ko) | 파동 기어 장치 | |
JP2510374B2 (ja) | 転動子を有する滑り・転がり兼用型軸受 | |
JP6327910B2 (ja) | 偏心揺動型の減速装置 | |
WO2023047650A1 (ja) | 波動歯車装置 | |
JP3186812U (ja) | 変速伝動ベアリング | |
EP3173665B1 (en) | Electric actuator | |
JP2023133538A (ja) | 撓み噛合い式歯車装置及びその製造方法 | |
US20020097931A1 (en) | Hydrodynamic bearing for motor | |
JP2016217391A (ja) | 波動減速機の波動発生装置 | |
JP2022065727A (ja) | 波動歯車装置及びアクチュエータ | |
WO2020031843A1 (ja) | 歯車機構、及び歯車機構の製造方法 | |
JP2009108964A (ja) | 二重カップ式減速機 | |
WO2023000885A1 (zh) | 谐波齿轮装置和致动器 | |
JP2017501360A (ja) | トランスミッション及びその部品 | |
JP7221077B2 (ja) | 撓み噛合い式歯車装置及びその製造方法 | |
WO2022163083A1 (ja) | 波動歯車装置 | |
JP2005172217A (ja) | 軸継手 | |
WO2023079701A1 (ja) | 波動歯車装置 | |
JP2023094974A (ja) | 波動歯車装置及びロボット用関節装置 | |
US11320034B2 (en) | Strain wave gearing having unit structure | |
JP2021110349A (ja) | 撓み噛合い式歯車装置 | |
JP2021113598A (ja) | 減速機 | |
TW202338231A (zh) | 波動齒輪裝置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 22872409 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 20247001884 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1020247001884 Country of ref document: KR |
|
WWE | Wipo information: entry into national phase |
Ref document number: 202280062396.5 Country of ref document: CN |
|
NENP | Non-entry into the national phase |
Ref country code: DE |