Patent Application
20170138408
Technical Field
The present disclosure relates to a shaft structure to be installed in shafts used for various industrial machines, and a male component and a female component included in the shaft structure.
Description of the Related Art
Conventionally, it has been well known that a shaft structure having an elastic member made of fabric impregnated with rubber or resin interposed between an outer peripheral part of a male component and an inner peripheral part of a female component (see e.g., Patent Document 1 shown below).
Patent Document 1: Japanese Patent Application Publication No. 2014-025580
It is described in Patent Document 1, however, that, on the assumption that the metallic parts of the male component and/or the female component are rigid bodies, the effect of improvement in the reduction and the resistance with respect to tooth-hit noise generated during the operation has been obtained by virtue of such an elastic member; nevertheless, the resistance of the elastic member has deteriorated (i) if the elastic member is continuously subjected to a load to such an extent that the elastic member cannot fully absorb the load, and (ii) if an axis of the male and/or female component is caused to be eccentric and/or deflected so that a part of the elastic member is continuously subjected to an excessively large load.
The objective of the present disclosure is to provide the shaft structure as well as the male and female components thereof, of which the resistance does not easily deteriorate even if (i) the elastic member interposed between an outer peripheral part of the male component and an inner peripheral part of the female component is continuously subjected to a load to such an extent that the elastic member cannot fully absorb the load, and even if (ii) an axis of the male and/or female component is caused to be eccentric and/or deflected so that a part of the elastic member is continuously subjected to an excessively large load.
[1] As one aspect of the present disclosure, there is provided a shaft structure installed in a shaft capable of making a power-transmission including: a male component having a plurality of male spline parts and a plurality of male spline bottom parts formed on an outer peripheral part thereof; a female component having a plurality of female spline parts and a plurality of female spline bottom parts formed on an inner peripheral part thereof, the female component configured to allow the male component to be slidably inserted thereinto in an axial direction thereby making up said shaft structure; and an elastic member arranged on the male or female component such that a surface of the outer or inner peripheral part of the male or female component, respectively, is covered with the elastic member, wherein the female component has a plurality of substantially U or V-shaped cross-section grooves each formed on an outer peripheral part as opposed to each of the plurality of female spline parts, and a shape defined by each of the plurality of female spline parts and each of the plurality of grooves is configured such that, when the male or female component is twisted with respect to each other and the stress is applied to a female spline part as each of the plurality of female spline parts in a direction around the shaft, the female spline part could be elastically deformed as well as absorb a maximum design stress within an elastic region of the female spline part.
[2] As one aspect of the present disclosure, there is provided a female component installed in a shaft capable of making a power-transmission including: a plurality of female spline parts formed on an inner peripheral part thereof; a plurality of female spline bottom parts formed on an inner peripheral part thereof; and a plurality of substantially U or V-shaped cross-section grooves each formed on an outer peripheral part thereof as opposed to each interval between adjacent male spline parts out of a plurality of male spline parts formed on an outer peripheral part of a male component in an initial state where the male component is inserted thereinto, thereby making up a shaft structure, wherein a shape defined by each of the plurality of female spline parts thereof and each of the plurality of grooves is configured such that, when the male component or said female component is twisted with respect to each other and the stress is applied to a female spline part as each of the plurality of female spline parts thereof in a direction around the shaft, through an elastic member arranged so as to cover a surface of the outer peripheral part of the plurality of male spline parts and a plurality of male spline bottom parts formed along with the plurality of male spline parts, or a surface of the inner peripheral part of the plurality of female spline parts thereof and the plurality of female spline bottom parts thereof, the female spline part could be elastically deformed as well as absorb a maximum design stress within an elastic region of the female spline part.
According to the construction of [1] and [2] above, in a state where the male component is inserted into the female component, when e.g., the male component is twisted in a peripheral direction with the rotation of the shaft, a force is transmitted to the female spline parts of the female component through the elastic member, and the female component is caused to rotate. When a load (torsional force) absorbable for the elastic member is applied to it, the elastic member is deformed so as to absorb a part of stress applied to the shaft by itself, and thereafter restores its original shape when the load (torsional force) disappears. On the other hand, when a large load (torsional force) not fully absorbable for the elastic member is applied to it, the elastic member is deformed but allows the load (torsional force) to be transmitted to a female spline part. In such a circumstance, the female spline part can be bent (elastically deformed) within the elastic region of material of the female component and restore its original shape when the load (torsional force) disappears. The stress applied to the elastic member can therefore be reduced by the deformation of the female spline part. When a large load (torsional force) not fully absorbable for the elastic member is applied to it with the rotation of the shaft, however, the stress concentrated on the elastic member can be distributed and reduced by the female spline part through the use of the elasticity of the material used as material of the female component.
Furthermore, when an axis of the male component and/or the female component is eccentric and/or deflected (in a state where the axis of the male component does not match an axis of the female component; the same herein below) with the rotation of the shaft, and a force is transmitted to the female component through the elastic member, and a load (pressure) absorbable for the elastic member is applied to it, the elastic member is deformed so as to burden itself with stress. On the other hand, when the axis of e.g., the male component is eccentric and/or deflected and a large load (pressure) not absorbable for the elastic member is applied to it, the elastic member is deformed but allows the load (pressure) to be transmitted from a part of the inner peripheral part of the female component.
As an example, when the male component is eccentric and allows the load (pressure) to be transmitted to the female spline part present in an eccentric direction of the axis of the male component, the load (pressure) is transmitted to the entire female spline part. In such a circumstance, the female spline part present in an eccentric direction of the axis of the male component and subjected to the transmitted load (pressure) can be bent (elastically deformed) within the elastic region of the material used as material of the female component, and a larger stress is applied to the female spline part in an eccentric direction than a female spline part present in an opposite direction of the female spline part. Furthermore, in such a circumstance, a large stress is also applied to the elastic member; however, the stress is reduced by the elastic deformation of the female spline part. The female spline part and the elastic member restore their original shape when the load (pressure) disappears.
As another example, when the axis of the male component is deflected in relation to the axis of the female component so as to allow a load (pressure) to be transmitted to the female spline part present in a deflection direction of the axis of the male component, the load (pressure) is transmitted to the spline crest part of the female spline part in a distributed manner in a longitudinal direction. In such a circumstance, a large stress is also applied to the elastic member; however, the stress applied to the elastic member is reduced by the bending (elastic deformation) of the female spline part in a distributed manner in a longitudinal direction within the elastic region of the material used as material of the female component around a part of the spline crest part of the female spline part of the female component subjected to the transmitted load (pressure). The elastic member and the female spline part restore their original shape when the load (pressure) disappears. It is possible therefore to reduce the stress applied to the elastic member by the deformation of the female spline part. The same effect is obtained when the axis of the female component is eccentric and/or deflected.
As a result, when the axis of the male component and/or the female component is eccentric and/or deflected, and a large load (pressure) not fully absorbable for the elastic member is applied to it, the stress concentrated on the elastic member can be distributed and reduced (absorbed) by the female spline part through the use of the elasticity of the material used as material of the female component. In other words, the stress (deformation amount) applied to the elastic member generated when the male component is twisted in a peripheral direction and the axis of the male component and/or the female component is eccentric and/or deflected can be reduced by the deformation of the female spline part.
As a consequence, this elastic member can be extended in service life in comparison with the conventional elastic member. In other words, it is possible to provide a shaft structure and a female component whose durability of elastic member does not easily deteriorate.
[3] As another aspect of the present disclosure, there is provided a shaft structure installed in a shaft capable of making a power-transmission including: a male component having a plurality of male spline parts and a plurality of male spline bottom parts formed on an outer peripheral part thereof, and having a hollow part formed therein; a female component having a plurality of female spline parts and a plurality of female spline bottom parts formed on an inner peripheral part thereof, the female component configured to allow the male component to be slidably inserted thereinto in an axial direction thereby making up said shaft structure; and an elastic member arranged on the male or female component such that a surface of the outer or inner peripheral part of the male or female component, respectively, is covered with the elastic member, wherein the male component has, in the hollow part, a plurality of substantially U or V-shaped cross-section grooves each shaped so as to converge from a hollow part side toward a spline crest part of each of the plurality of male spline parts, and a shape defined by each of the plurality of male spline parts and each of the plurality of grooves is configured such that, when the male or female component is twisted with respect to each other and the stress is applied to a male spline part as each of the plurality of male spline parts in a direction around the shaft, the male spline part could be elastically deformed as well as absorb a maximum design stress within an elastic region of the male spline part.
[4] As another aspect of the present disclosure, there is provided a male component installed in a shaft capable of making a power-transmission including: a plurality of male spline parts formed on an outer peripheral part thereof; a plurality of male spline bottom parts formed on an outer peripheral part thereof; a hollow part formed therein; and a plurality of substantially U or V-shaped cross-section grooves each shaped so as to converge from a hollow part side toward a spline crest part of each of the plurality of male spline parts, in the hollow part, thereof, wherein a shape defined by each of the plurality of male spline parts thereof and each of the plurality of grooves is configured such that, when said male component or a female component is twisted with respect to each other from an initial state where said male component is inserted into the female component, thereby making up a shaft structure, and the stress is applied to a male spline part as each of the plurality of male spline parts thereof in a direction around the shaft, through an elastic member arranged so as to cover a surface of the outer peripheral part of the plurality of male spline parts thereof and the plurality of male spline bottom parts thereof, or a surface of an inner peripheral part of a plurality of female spline parts of the female component and a plurality of female spline bottom parts formed along with the plurality of female spline parts, the male spline part could be elastically deformed as well as absorb a maximum design stress within an elastic region of the male spline part.
According to the construction of [3] and [4] above, in a state where the male component is inserted into the female component, when e.g., the male component is twisted in a peripheral direction with the rotation of the shaft, a force is transmitted to the female component through the elastic member, and the female component is caused to rotate. When a load (torsional force) absorbable for the elastic member is applied from the male component to the elastic member, the elastic member is deformed so as to absorb a part of the stress applied to the shaft, and thereafter restores its original shape when the load (torsional force) disappears. On the other hand, when a large load (torsional force) not fully absorbable for the elastic member is applied to it, the elastic member is deformed but allows the load (torsional force) to be transmitted to the male spline part as a reactive force. In such a circumstance, the male spline part can be bent (elastically deformed) within the elastic region of the material used as material of the male component and restore its original shape when the load (torsional force) disappears. The stress applied to the elastic member can therefore be reduced by the deformation of the male spline part. When a large load (torsional force) not fully absorbable for the elastic member is applied to it with the rotation of the shaft, however, the stress concentrated on the elastic member can be distributed and reduced by the male spline part through the use of the elasticity of the material used as material of the male component.
Furthermore, when an axis of the male component and/or the female component is eccentric and/or deflected with the rotation of the shaft, and a force is transmitted to the male component and/or the female component through the elastic member, and a load (pressure) absorbable for the elastic member is applied to it, the elastic member is deformed so as to absorb a part of the stress applied to the shaft and restores its original shape when the load (torsional force) disappears. On the other hand, when the axis of e.g., the male component is eccentric and/or deflected and a large load (pressure) not absorbable for the elastic member is applied to it, the elastic member is deformed but allows a part of the load (pressure) to be transmitted to the female component, and a part of the load (pressure) is transmitted from a part of the outer peripheral part of the male component as a reactive force. More specific example of transmission of the load (pressure) will be described.
As an example, a larger stress is applied to the male spline part present in an eccentric direction than the stress applied to a male spline part present in an opposite direction of the male spline part. In such a circumstance, a large stress is also applied to the elastic member; however, the stress is reduced by the elastic deformation of the male spline part. The male spline part and the elastic member restore their original shape when the load (pressure) disappears.
As another example, when the axis of the male component is deflected in relation to an axis of the female component, and a load (pressure) is transmitted to the spline crest part of the male spline part present in a deflection direction of the axis of the male component, the load (pressure) is transmitted to the spline crest part of the male spline part in a distributed manner in a longitudinal direction. In such a circumstance, a large stress is also applied to the elastic member; however, the stress applied to the elastic member is reduced by the bending (elastically deformed) of the male spline part in a distributed manner in a longitudinal direction within the elastic region of the material used as material of the male component around a part of the spline crest part of the male spline part subjected to the transmitted load (pressure). The elastic member and the male spline part restore their original shape when the load (pressure) disappears. It is possible therefore to distribute and reduce a part of the stress applied to the shaft by the elastic member and the male spline part. The same effect is obtained when the axis of the female component is eccentric and/or deflected.
As a result, when the axis of the male component and/or the female component is eccentric and/or deflected, and a large load (pressure) not fully absorbable for the elastic member is applied to it, the stress concentrated on the elastic member can be distributed and reduced by the male spline part through the use of the elasticity of the material used as material of the male component. In other words, the stress (deformation amount) applied to the elastic member generated when the male component is twisted in a peripheral direction and the axis of the male component and/or the female component is eccentric and/or deflected can be reduced by the deformation of the male spline part.
As a consequence, the elastic member can be extended in service life in comparison with the conventional elastic member. In other words, it is possible to provide a shaft structure and a male component in whose durability of the elastic member does not easily deteriorate.
[5] As still another aspect of the present disclosure, there is provided a shaft structure installed in a shaft capable of making a power-transmission including: a male component having a plurality of male spline parts and a plurality of male spline bottom parts formed on an outer peripheral part thereof; a female component having a plurality of female spline parts and a plurality of female spline bottom parts formed on an inner peripheral part thereof, the female component configured to allow the male component to be slidably inserted thereinto in a radial direction thereby making up said shaft structure; and an elastic member arranged on the male or female component such that a surface of the outer or inner peripheral part of the male or female component, respectively, is covered with the elastic member, wherein the male component has a plurality of substantially U or V-shaped cross-section grooves each shaped so as to converge from a spline crest part toward a central part in a radial direction of each of the plurality of male spline parts, and a shape defined by each of the plurality of male spline parts and each of the plurality of grooves is configured such that, when the male or female component is twisted with respect to each other and the stress is applied to a male spline part as each of the plurality of male spline parts in a direction around the shaft, the male spline part could be elastically deformed as well as absorb a maximum design stress within an elastic region of the male spline part.
[6] As still another aspect of the present disclosure, there is provided a male component installed in a shaft capable of making a power-transmission including: a plurality of male spline parts formed on an outer peripheral part thereof; a plurality of male spline bottom parts formed on an outer peripheral part thereof; and a plurality of substantially U or V-shaped cross-section grooves each shaped so as to converge from a spline crest part to a central part in a radial direction of each of the plurality of male spline parts, in the hollow part, thereof, wherein a shape defined by each of the plurality of male spline parts thereof and each of the plurality of grooves is configured such that, when said male component or a female component is twisted with respect to each other from an initial state where said male component is inserted into the female component, thereby making up a shaft structure, and the stress is applied to a male spline part as each of the plurality of male spline parts thereof in a direction around the shaft, through an elastic member arranged so as to cover a surface of the outer peripheral part of the plurality of male spline parts thereof and the plurality of male spline bottom parts thereof, or a surface of an inner peripheral part of a plurality of female spline parts of the female component and a plurality of female spline bottom parts formed along with the plurality of female spline parts, the male spline part could be elastically deformed as well as absorb a maximum design stress within an elastic region of the male spline part.
According to the construction of [5] and [6] above, in a state where the male component is inserted into the female component, when e.g., the male component is twisted in a peripheral direction with the rotation of the shaft, a force is transmitted to the female component through the elastic member, and the female component is caused to rotate. When a load (torsional force) absorbable for the elastic member is applied from the male component to the elastic member, the elastic member is deformed so as to absorb a part of the stress applied to the shaft by itself, and thereafter restores its original shape when the load (torsional force) disappears. On the other hand, when a large load (torsional force) not fully absorbable for the elastic member is applied to it, the elastic member is deformed but allows the load (torsional force) to be transmitted to a side portion of the male spline part as a reactive force. In such a circumstance, the male spline part can be bent (elastically deformed) in a peripheral direction within the elastic region of the material used as material of the male component and restore its original shape when the load (torsional force) disappears. The stress applied to the elastic member can therefore be reduced by the deformation of the male spline part. When a large load (torsional force) not fully absorbable for the elastic member is applied to it with the rotation of the shaft, however, the stress concentrated on the elastic member can be distributed and reduced by the male spline part through the use of the elasticity of the material used as material of the male component.
Furthermore, when an axis of the male component and/or the female component is eccentric and/or deflected with the rotation of the shaft, and a force is transmitted to the male component and/or the female component through the elastic member, and a load (pressure) absorbable for the elastic member is applied to it, the elastic member is deformed so as to absorb a part of the stress applied to the shaft and restores its original shape when the load (torsional force) disappears. On the other hand, when the axis of e.g., the male component is eccentric and a large load (pressure) not absorbable for the elastic member is applied to it, the elastic member is deformed but allows a part of the load (pressure) to be distributed around a part of the outer peripheral part of the female component.
As an example, a larger stress is applied to the male spline part present in an eccentric direction than the stress applied to a male spline part present in an opposite direction of the male spline part. In such a circumstance, a large stress is also applied to the elastic member; however, the stress is reduced by the elastic deformation of the male spline part. The male spline part and the elastic member restore their original shape when the load (pressure) disappears.
As another example, when the axis of the male component is deflected in relation to an axis of the female component, and a load (pressure) is transmitted to the spline crest part of the male spline part present in a deflection direction of the axis of the male component, the load (pressure) is transmitted to the spline crest part of the male spline part in a distributed manner in a longitudinal direction. In such a circumstance, a large stress is also applied to the elastic member; however, the stress applied to the elastic member is reduced by the bending (elastically deformed) of the male spline part in a distributed manner in a longitudinal direction within the elastic region of the material used as material of the male component around a part of the spline crest part of the male spline part subjected to the transmitted load (pressure). The elastic member and the male spline part restore their original shape when the load (pressure) disappears. It is possible therefore to reduce the stress applied to the shaft by the elastic member. The same effect is obtained when the axis of the female component is eccentric and/or deflected.
As a result, when the axis of the male component and/or the female component is eccentric and/or deflected, and a large load (pressure) not fully absorbable for the elastic member is applied to it, the stress concentrated on the elastic member can be distributed and reduced by the male spline part through the use of the elasticity of the material used as material of the male component. In other words, the stress (deformation amount) applied to the elastic member generated when the male component is twisted in a peripheral direction and the axis of the male component and/or the female component is eccentric and/or deflected can be reduced by the deformation of the male spline part.
As a consequence, the elastic member can be extended in service life in comparison with the conventional elastic member. In other words, it is possible to provide a shaft structure and a male component in whose durability of the elastic member does not easily deteriorate.
For more thorough understanding of the present disclosure and advantages thereof, the following descriptions should be read in conjunction with the accompanying drawings in which:
Hereinafter, a shaft structure (spline) as well as a male component (male spline shaft) and a female component (female spline shaft), both components making up the shaft structure, in a first embodiment of the present disclosure will be described with reference to
(Outlined Structure of Electric Power Steering Device)
Explanations about the elements of an electric power steering device along with further explanations about the operation of such a device will be provided here. As shown in
The rack shaft 6 has tie rods 7 connected to both ends thereof, respectively, and the tie rods 7 are connected to their respective wheels 8 through their respective knuckle arms (not shown). When the steering wheel 2 is manipulated so as to cause the steering shaft 3 to rotate, the rotational motion of the steering shaft 3 is converted by the pinion gear 4 and the rack gear 5 to the translational motion of the rack shaft 6 in a lateral direction of the vehicle. As a result, the steering of the wheels 8 can be thus achieved.
The steering shaft 3 is separated into an input shaft 9 connected to the steering wheel 2 and an output shaft 10 connected to the pinion gear 4. Such input/output shafts 9, 10 are coupled to each other through a torsion bar 11 along the same axis. Further, a torque sensor 12 is provided so as to detect steering torque on the basis of an amount of relative rotational displacement between the input and output shafts 9, 10 with respect to the torsion bar 11 interposed therebetween, and output torque-detection results obtained by the torque sensor 12 to a control unit 13. On the basis of: torque-detection results obtained by the torque sensor 12; vehicle-speed-detection results; and the like, the control unit 13 controls a driver 14 so as to adjust a voltage applied to an electric motor 15 for assistance in steering. Still further, the rotation of a rotary shaft (not shown) in the electric motor 15 is decreased in speed through a speed reducer 17. The outputted rotational motion of the speed reducer 17 is converted through a converter 18 to the translational motion of the rack shaft 6 in an axial direction, thereby resulting in assistance in steering. This electric power steering device 1 is that of the so-called rack assist type.
(Structure of Shaft Structure)
The shaft structure 20 in this embodiment is applied to e.g., the steering shaft 3 described above (hereinafter, occasionally referred to as “shaft 3” for short).
The shaft structure 20 according to the present disclosure is installed on a shaft 3 capable of making a power-transmission. The male and female components capable of making a power-transmission are configured such that the male component is slidably inserted into the female component in an axial direction, thereby making up such a shaft structure 20. The shaft structure 20 includes a metallic male component 21, a metallic female component 22, and an elastic member 23 interposed between the male component 21 and the female component 22, where examples of metal used for the male component 21 and the female component 22 include iron, aluminum, stainless steel, and the like.
As shown in
As shown in
The elastic member 23 can be made of rubber. As such types of rubber, the followings may be used in a neat form or in a form denatured in various ways: e.g., urethane rubber, nitrile rubber (NBR), silicon rubber, fluororubber, acrylic rubber, ethylene-propylene rubber, butyl rubber, isoprene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, chloroprene rubber, polybutadiene rubber, styrene-butadiene rubber, natural rubber, and the like. Each of these types of rubber may be used alone, or a plurality of types of rubber selected therefrom may be used in a blended form.
It is preferable that the elastic member 23 is made of fabric impregnated with rubber or resin. The fabric may be made of, e.g., aramid fiber, nylon, urethane, cotton, silk, linen, acetate, rayon, fluorine-containing fiber, polyester, and the like, which are impregnated with rubber or resin. The fabric may be made of e.g., short fibers or long fibers, and may also be a sheet-like fabric.
By virtue of impregnating fibers with rubber or resin, rubber material or resin material is enabled to fill the gaps among the fibers and bond the fibers together, thereby allowing the fibers to serve as a component (sheet body) like the elastic member 23. Further, by adopting fibers impregnated with rubber or resin as the elastic member 23, the wear caused by friction between the fibers can be reduced, and still further, the resistance to wear on the surface of the elastic member 23 caused by friction between the elastic member 23 and the male component 21 or the elastic member 23 and the female component 22 can be improved.
As rubber to be subjected to impregnation processing, the followings may be used in a neat form or in a form denatured in various ways: e.g., urethane rubber, nitrile rubber (NBR), silicon rubber, fluororubber, acrylic rubber, ethylene-propylene rubber, butyl rubber, isoprene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, chloroprene rubber, polybutadiene rubber, styrene-butadiene rubber, natural rubber, and the like. Each of these types of rubber may be used alone, or a plurality of types of rubber selected therefrom may be used in a blended form. Further, the rubber may contain appropriate amounts of traditional compounding ingredients for rubber, such as vulcanizing agent, vulcanizing accelerator, antioxidant, softener, plasticizer, filler, colorant, and the like as well as solid lubricants such as graphite, silicone oil, fluorine powder, molybdenum disulfide, or the like for enhancing the lubricity of the elastic member 23. Still further, the above types of rubber may be replaced by or combined with thermoplastic or thermosetting resin such as acrylic resin, polyester resin, urethane resin, vinyl chloride resin, polypropylene, polycarbonate, polyethylene terephthalate resin, fluorine resin, polyethylene, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin, polystyrene resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, nylon, alkyd resin, phenolic resin, epoxy resin, polyphenylene sulfide resin, and the like.
When impregnating fibers with rubber or resin as described above, it is preferable that the rubber or resin be dissolved by a solvent or another means into a liquid state before dipping the predetermined fibers (short or long fibers) in the liquid. In practice, the sheet-like fabric made of the fibers may be used. This fabric is impregnated with rubber or resin in the same way as described above.
The fabric may be, e.g., non-woven fabric made of irregularly tangled fibers, regularly-formed woven, knitted fabric, and the like. These fabrics are characterized by facilitating impregnation (easier handling) with rubber and the like, and further facilitating adhesion to the surface of the shaft structure described below in comparison with those made of fibers (short or long fibers) only, because these fabrics are in sheet form. The woven fabric may be made in a plain weave, satin weave, twill weave, or the like.
The fabric may preferably be stretchy to some extent. By virtue of such stretchiness, when the fabric is formed so as to be in line with the male spline parts 21c or female spline parts 22c in shape, or when the fabric is adhered to a surface of the outer peripheral part 21b of the male component 21 and a surface of the inner peripheral part 22a of the female component 22, there can be achieved the advantageous effects that a surface of the stretchy fabric can easily be shaped in accordance with any concave-convex formed surfaces, and the resultant elastic member 23 has the surface subjected to few creases and uniformly finished.
As shown in
(Operation of Present Embodiment)
As shown in
Furthermore, the axis of the male component 21 and/or the female component 22 is eccentric and/or deflected, the stress applied to the elastic member 23 is not uniform but an excessively large stress is applied to only a part thereof. When the axis is eccentric, in the case of the shaft structure shown in e.g.,
As a result, a service life of the elastic member 23 can be extended in comparison with the conventional elastic member. In other words, it is possible to provide the shaft structure 20 whose durability of the elastic member 23 does not easily deteriorate. Furthermore, when the elastic member 23 is formed of a fiber member impregnated with rubber or resins, it is possible to simultaneously solve the problems of suppressing an unpleasant sound called a tooth-hit noise generated between the outer peripheral part 21b of the male component 21 and the inner peripheral part 22a of the female component 22, and reducing an axial sliding resistance of the male component 21 and the female component 22, which are in a trade-off relation. Furthermore, since the axial sliding property of the male component 21 and the female component 22 is improved, it is not necessary to supply lubricant between the outer peripheral part 21b of the male component 21 and the inner peripheral part 22a of the female component 22 and to eliminate the lab and/or time necessary for supplying the lubricant. Furthermore, since the fiber member is impregnated with rubber or resins, it is possible to improve the resistance to wear of the surface of the fiber member generated between the fiber member and the outer peripheral part 21b of the male component 21 or between the fiber member and the inner peripheral part 22a of the female component 22.
Hereinafter, a shaft structure (spline) as well as a male component (male spline shaft) and a female component (female spline shaft), both components making up the shaft structure, in a second embodiment of the present disclosure will be described with reference to
(Structure of Shaft Structure)
The shaft structure 30 in this embodiment is applied to e.g., a steering shaft similar to the steering shaft 3 described above (hereinafter, occasionally referred to as “shaft 3” for short).
The shaft structure 30 according to the present disclosure is installed on a shaft (hereinafter, referred merely to as “shaft”) similar to the shaft 3 as a first embodiment. The male and female components capable of making a power-transmission are configured such that the male component is slidably inserted into the female component in an axial direction, thereby making up such a shaft structure 30. The shaft structure 30 includes a metallic male component 31, a metallic female component 32, and an elastic member 33 interposed between the male component 31 and the female component 32, where examples of metal used for the male component 31 and the female component 32 include iron, aluminum, stainless steel, and the like.
As shown in
As shown in
The elastic member 33 can be formed using the same material as the elastic member 23 of the first embodiment. Furthermore, the elastic member 33 can be formed of a fiber member impregnated with rubber or resins similarly to the elastic member 23 of the first embodiment.
As shown in
(Operation of Present Embodiment)
As shown in
Furthermore, in a state where the male component 31 is inserted into the female component 32, when the male component 31 is caused to rotate around the shaft with the rotation of the shaft, and the axis of the male component 31 and/or the female component 32 is eccentric and/or deflected, a force is transmitted to the male component 31 and/or the female component 32 through the elastic member 33, and such a load (pressure) absorbable for the elastic member 33 is applied to the elastic member 33, the elastic member 33 only is deformed so as to absorb a part of the stress applied to the shaft and restores its original shape when the load (torsional force) disappears. On the other hand, when e.g., the male component 31 is twisted around the shaft with the rotation of the shaft, the axis of the male component 31 is eccentric and/or deflected, and such a large load (pressure) that not fully absorbable for the elastic member 33 is applied to the elastic member 33, the elastic member 33 is deformed, a part of the load (pressure) is transmitted to the female component 32, and a part of the load (pressure) is transmitted from a part of the outer peripheral part of the male component 31 as a reactive force. A specific example of the above-described transmission of the load (pressure) when the axis is eccentric or deflected will be described below. For example, a larger stress is applied to the male spline part 31c in an eccentric direction than that applied to a male spline part 31c in an opposite direction. In this case, although a large stress is also applied to the elastic member 33, the male spline part 31c is elastically deformed to reduce the stress. The elastic member 33 and the male spline part 31c restore their original shape when the load (pressure) disappears. Furthermore, for example, when the axis of the male component 31 is deflected in relation to the axis of the female component 32 and a load (pressure) is transmitted to a spline crest part of the male spline part 31c present in a deflection direction of the axis of the male component 31, the load (pressure) is transmitted to the spline crest part of the male spline part 31c in a distributed manner in a longitudinal direction. In this case, although a large stress is also applied to the elastic member 33, the male spline part 31c is bent (elastically deformed) within the elastic region of the material used as the material of the male component 31, in a distributed manner in a longitudinal direction around a part of the spline crest part of the male spline part 31c to which the load (pressure) has been transmitted, whereby the stress applied to the elastic member 33 is reduced. The elastic member 33 and the male spline part 31c restore their original shape when the load (pressure) disappears. Due to this, it is possible to reduce the stress applied to the elastic member 33 with deformation of the male spline part 31c. The same effect is obtained when the axis of the female component 32 is eccentric and/or deflected. Therefore, when the axis of the male component 31 and/or the female component 32 is eccentric and/or deflected and such a large load (pressure) that not fully absorbable for the elastic member 33 is applied to the elastic member 33, concentration of stress on the elastic member 33 can be distributed and reduced by the male spline part 31c using the elasticity of the metal used as the material of the male component 31. That is, the stress (deformation amount) applied to the elastic member 33 generated when the male component 31 is twisted in a peripheral direction and the axis of the male component 31 and/or the female component 32 is eccentric and/or deflected can be reduced by deformation of the male spline part 31c.
As a result, the service life of the elastic member 33 can be extended as compared to the conventional elastic member. That is, it is possible to provide the shaft structure 30 in which the durability of the elastic member 33 does not easily deteriorate. Furthermore, when the elastic member 33 is formed of a fiber member impregnated with rubber or resins, it is possible to simultaneously solve the problems of suppressing an unpleasant sound called a tooth-hit noise generated between the outer peripheral part 31b of the male component 31 and the inner peripheral part 32a of the female component 32, and reducing an axial sliding resistance of the male component 31 and the female component 32, which are in a trade-off relation. Furthermore, since the axial sliding property of the male component 31 and the female component 32 is improved, it is not necessary to supply lubricant between the outer peripheral part 31b of the male component 31 and the inner peripheral part 32a of the female component 32 and to eliminate the lab and/or time necessary for supplying the lubricant. Furthermore, since the fiber member is impregnated with rubber or resins, it is possible to improve the resistance to wear of the surface of the fiber member generated between the fiber member and the outer peripheral part 31b of the male component 31 or between the fiber member and the inner peripheral part 32a of the female component 32.
Hereinafter, a shaft structure (spline) as well as a male component (male spline shaft) and a female component (female spline shaft), both components making up the shaft structure, in a third embodiment of the present disclosure will be described with reference to
(Structure of Shaft Structure)
The shaft structure 40 in this embodiment is applied to e.g., a shaft similar to the shaft 3 as a first embodiment (hereinafter, referred merely to as “shaft”).
The shaft structure 40 according to the present disclosure is installed on the shaft. The male and female components capable of making a power-transmission are configured such that the male component is slidably inserted into the female component in an axial direction, thereby making up such a shaft structure 40. The shaft structure 40 includes a metallic male component 41, a metallic female component 42, and an elastic member 43 interposed between the male component 41 and the female component 42.
As shown in
As shown in
The elastic member 43 can be formed using the same material as the elastic member 23 of the first embodiment. Furthermore, the elastic member 43 can be formed of a fiber member impregnated with rubber or resins similarly to the elastic member 23 of the first embodiment.
As shown in
(Operation of Present Embodiment)
As shown in
Furthermore, when the male component 41 is caused to rotate around the shaft with the rotation of the shaft from the initial state where the male component 41 is inserted into the female component 42, and the axis of the male component 41 and/or the female component 42 is eccentric and/or deflected, force is transmitted to the male component 41 and/or the female component 42 through the elastic member 43, and such a load (pressure) absorbable for the elastic member 43 is applied to the elastic member 43, the elastic member 43 only is deformed to absorb a part of the stress applied to the shaft and restores its original shape when the load (torsional force) disappears. On the other hand, for example, when the male component 41 is twisted abound the shaft with the rotation of the shaft from the initial state where the male component 41 is inserted into the female component 42, the axis of the male component 41 is eccentric and/or deflected, and such a large load (pressure) that not fully absorbable for the elastic member 43 is applied to the elastic member 43, the elastic member 43 is deformed, a part of the load (pressure) is transmitted to the female component 42, and a part of the load (pressure) is transmitted from a part of the outer peripheral part of the male component 41 as a reactive force. Here, a specific example of the above-described transmission of the load (pressure) when the axis is eccentric or deflected will be described below. For example, a larger stress is applied to the male spline part 41c in an eccentric direction than that applied to a male spline part 41c in an opposite direction. In this case, although a large stress is also applied to the elastic member 43, the male spline part 41c is elastically deformed to reduce the stress. The elastic member 43 and the male spline part 41c restore their original shape when the load (pressure) disappears. Furthermore, for example, when the axis of the male component 41 is deflected in relation to the axis of the female component 42 and a load (pressure) is transmitted to a spline crest part of the male spline part 41c present in a deflection direction of the axis of the male component 41, the load (pressure) is transmitted to the spline crest part of the male spline part 41c in a distributed manner in a longitudinal direction. In this case, although a large stress is also applied to the elastic member 43, the male spline part 41c is bent (elastically deformed) within the elastic region of the material used as the material of the male component 41 in a distributed manner in a longitudinal direction around a part of the spline crest part of the male spline part 41c to which the load (pressure) has been transmitted, whereby the stress applied to the elastic member 43 is reduced. The elastic member 43 and the male spline part 41c restore their original shape when the load (pressure) disappears. Due to this, it is possible to reduce the stress applied to the elastic member 43 with deformation of the male spline part 41c. The same effect is obtained when the axis of the female component 42 is eccentric and/or deflected. Therefore, when the axis of the male component 41 and/or the female component 42 is eccentric and/or deflected and such a large load (pressure) that not fully absorbable for the elastic member 43 is applied to the elastic member 43, concentration of stress on the elastic member 43 can be distributed and reduced by the male spline part 41c using the elasticity of the metal used as the material of the male component 41. That is, the stress (deformation amount) applied to the elastic member 43 generated when the male component 41 is twisted in a peripheral direction and the axis of the male component 41 and/or the female component 42 is eccentric and/or deflected can be reduced by deformation of the male spline part 41c.
As a result, the service life of the elastic member 43 can be extended as compared to the conventional elastic member. That is, it is possible to provide the shaft structure 40 in which the durability of the elastic member 43 does not easily deteriorate. Furthermore, when the elastic member 43 is formed of a fiber member impregnated with rubber or resins, it is possible to simultaneously solve the problems of suppressing an unpleasant sound called a tooth-hit noise generated between the outer peripheral part 41b of the male component 41 and the inner peripheral part 42a of the female component 42, and reducing an axial sliding resistance of the male component 41 and the female component 42, which are in a trade-off relation. Furthermore, since the axial sliding property of the male component 41 and the female component 42 is improved, it is not necessary to supply lubricant between the outer peripheral part 41b of the male component 41 and the inner peripheral part 42a of the female component 42 and to eliminate the lab and/or time necessary for supplying the lubricant. Furthermore, since the fiber member is impregnated with rubber or resins, it is possible to improve the resistance to wear of the surface of the fiber member generated between the fiber member and the outer peripheral part 41b of the male component 41 or between the fiber member and the inner peripheral part 42a of the female component 42.
Hereinafter, a shaft structure (spline) as well as a male component (male spline shaft) and a female component (female spline shaft), both components making up the shaft structure, in a fourth embodiment of the present disclosure will be described with reference to
(Structure of Shaft Structure)
The shaft structure 50 in this embodiment is applied to e.g., a shaft similar to the shaft 3 as a first embodiment (hereinafter, referred merely to as “shaft”).
The shaft structure 50 according to the present disclosure is installed on the shaft. The male and female components capable of making a power-transmission are configured such that the male component is slidably inserted into the female component in an axial direction, thereby making up such a shaft structure 50. The shaft structure 50 includes a metallic male component 51, a metallic female component 52, and an elastic member 53 interposed between the male component 51 and the female component 52.
As shown in
As shown in
As shown in
Furthermore, the elastic member 53 can be formed using the same material as the elastic member 23 of the first embodiment. Furthermore, the elastic member 53 can be formed of a fiber member impregnated with rubber or resins similarly to the elastic member 23 of the first embodiment.
(Operation of Present Embodiment)
As shown in
Furthermore, when the male component 51 is caused to rotate around the shaft with the rotation of the shaft from the initial state where the male component 51 is inserted into the female component 52, and the axis of the male component 51 and/or the female component 52 is eccentric and/or deflected, force is transmitted to the male component 51 and/or the female component 52 through the elastic member 53, and such a load (pressure) absorbable for the elastic member 53 is applied to the elastic member 53, the elastic member 53 only is deformed to absorb a part of the stress applied to the shaft and restores its original shape when the load (torsional force) disappears. On the other hand, for example, when the male component 51 is twisted abound the shaft from the initial state where the male component 51 is inserted into the female component 52, and the axis of the male component 51 is eccentric, and such a large load (pressure) that not fully absorbable for the elastic member 53 is applied to the elastic member 53, the elastic member 53 is deformed, a part of the load (pressure) is transmitted from a part (e.g., a certain female spline part 52c present in an eccentric direction of the axis of the male component 51) of the inner peripheral part 52a of the female component 52, the load (pressure) transmitted to the female component 52 is applied as a reactive force, and a part of the load (pressure) is transmitted from a part (e.g., a certain male spline part 51c present in the eccentric direction of the axis of the male component 51) of the outer peripheral part 51b of the male component 51. In this case, a part (e.g., a certain female spline part 52c present in an eccentric direction of the axis of the male component 51) of the inner peripheral part 52a of the female component 52 can be bent (elastically deformed) around a part (e.g., a certain female spline part 52c present in an eccentric direction of the axis of the male component 51) of the inner peripheral part 52a of the female component 52 to which the load (pressure) has been transmitted) within the elastic region of the material used as the material of the female component 52 and restores its original shape when the load (pressure) disappears. Furthermore, a part (e.g., a certain male spline part 51c present in an eccentric direction of the axis of the male component 51) of the outer peripheral part 51b of the male component 51 can be bent (elastically deformed so that the width w2 in
As a result, the service life of the elastic member 53 can be extended as compared to the conventional elastic member. That is, it is possible to provide the shaft structure 50 in which the durability of the elastic member 53 does not easily deteriorate. Furthermore, when the elastic member 53 is formed of a fiber member impregnated with rubber or resins, it is possible to simultaneously solve the problem of suppressing an unpleasant sound called a tooth-hit noise generated between the outer peripheral part 51b of the male component 51 and the inner peripheral part 52a of the female component 52, and to reducing an axial sliding resistance of the male component 51 and the female component 52, which are in a trade-off relation. Furthermore, since the axial sliding property of the male component 51 and the female component 52 is improved, it is not necessary to supply lubricant between the outer peripheral part 51b of the male component 51 and the inner peripheral part 52a of the female component 52 and to eliminate the lab and/or time necessary for supplying the lubricant. Furthermore, since the fiber member is impregnated with rubber or resins, it is possible to improve the resistance to wear of the surface of the fiber member generated between the fiber member and the outer peripheral part 51b of the male component 51 or between the fiber member and the inner peripheral part 52a of the female component 52.
Specific constructions according to the present disclosure are not limited to embodiments described above with reference to the drawings. The scope of the present disclosure is not encompassed by the above explanations of embodiments but particularly pointed out by the claims, and the equivalents of the claim recitations as well as all the modifications within the scope of the claims fall within the scope of the present disclosure.
More specifically, in each embodiment, there is described an example of applying the shaft structure as this embodiment to a vehicle steering shaft; however, the present disclosure is not limited to this but may be applied to shafts used in various industrial machines.
Furthermore, in each embodiment, there is described the use of a metallic male component and a metallic female component; however, the present disclosure is not limited to this but the male component and the female component thereof may be formed of arbitrary material such as resins as long as the material has an elastic region.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-156046 | Jul 2014 | JP | national |
This is a continuation application of International Patent Application No. PCT/JP2015/066471, filed Jun. 08, 2015 claiming priority upon Japanese Patent Application No. 2014-156046, filed Jul. 31, 2014, of which full contents are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2015/066471 | Jun 2015 | US |
| Child | 15419762 | US |
