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WO2017010553A1 - Vis sphérique et actionneur à commande électrique doté de celle-ci - Google Patents

Vis sphérique et actionneur à commande électrique doté de celle-ci Download PDF

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Publication number
WO2017010553A1
WO2017010553A1 PCT/JP2016/070900 JP2016070900W WO2017010553A1 WO 2017010553 A1 WO2017010553 A1 WO 2017010553A1 JP 2016070900 W JP2016070900 W JP 2016070900W WO 2017010553 A1 WO2017010553 A1 WO 2017010553A1
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WO
WIPO (PCT)
Prior art keywords
screw
thread groove
nut
ball
screw shaft
Prior art date
Application number
PCT/JP2016/070900
Other languages
English (en)
Japanese (ja)
Inventor
慎介 平野
Original Assignee
Ntn株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ntn株式会社 filed Critical Ntn株式会社
Publication of WO2017010553A1 publication Critical patent/WO2017010553A1/fr

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    • 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
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with 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
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/06—Means for converting reciprocating motion into rotary motion or vice versa
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears

Definitions

  • the present invention converts a ball screw used in a drive unit of a general industrial electric motor, automobile, etc., more specifically, a rotation input from an electric motor into a linear motion of a drive shaft in an automobile transmission, a parking brake, or the like.
  • the present invention relates to a ball screw and an electric actuator provided with the ball screw.
  • a gear mechanism such as a trapezoidal screw or a rack and pinion is generally used as a mechanism for converting the rotational motion of the electric motor into a linear linear motion. Since these conversion mechanisms involve a sliding contact portion, the power loss is large, and it is necessary to increase the size of the electric motor and increase the power consumption. Therefore, a ball screw mechanism has been adopted as a more efficient actuator.
  • an electric motor supported by a housing can freely rotate a ball screw shaft constituting a ball screw, and an output member coupled to a nut by rotating the ball screw shaft. Displaceable in the axial direction.
  • the ball screw mechanism has a very small frictional resistance, and the ball screw shaft is easily rotated by a thrust load acting on the output member side. Therefore, it is necessary to hold the position of the output member when the electric motor is stopped.
  • the electric actuator 51 includes a cylindrical housing 52, an electric motor (not shown) attached to the housing 52, and an intermediate gear 54 that meshes with an input gear 53 attached to a motor shaft 53a of the electric motor.
  • a reduction mechanism 56 comprising an output gear 55 meshing with the intermediate gear 54, and a ball screw mechanism 58 for converting the rotational movement of the electric motor into the linear movement of the drive shaft 57 via the reduction mechanism 56; And an actuator body 59 having the ball screw mechanism 58.
  • the housing 52 is made of an aluminum alloy, and includes a first housing 52a and a second housing 52b abutted on the end surface thereof.
  • the first housing 52a is provided with an electric motor, and the first housing Bag holes 61 and 62 for accommodating the screw shaft 60 are formed in the abutting portion between the second housing 52b and the second housing 52b.
  • the motor shaft 53a of the electric motor has an input gear 53 attached to its end portion so as not to be relatively rotatable by press fitting, and is rotatably supported by a rolling bearing 63 comprising a deep groove ball bearing mounted on the second housing 52b.
  • An output gear 55 that meshes with an intermediate gear 54 that is a spur gear is integrally fixed to a nut 64 that constitutes a ball screw mechanism 58 via a key 65.
  • the drive shaft 57 is configured integrally with a screw shaft 60 constituting a ball screw mechanism 58, and a locking pin 66 is implanted at one end portion (right end portion in the figure) of the drive shaft 57.
  • a steel sleeve 67 is fastened to the bag hole 62 of the second housing 52b. Then, the locking pin 66 of the screw shaft 60 is engaged with the concave grooves 67a and 67a formed in the axial direction at positions opposed to the circumferential direction of the sleeve 67, so that the screw shaft 60 cannot rotate and moves in the axial direction. Supported as possible.
  • the ball screw mechanism 58 includes a screw shaft 60 and a nut 64 that is externally inserted to the screw shaft 60 via a ball 68.
  • the screw shaft 60 has a spiral thread groove 60a formed on the outer periphery.
  • the nut 64 is extrapolated to the screw shaft 60, and a helical screw groove 64a corresponding to the screw groove 60a of the screw shaft 60 is formed on the inner periphery, and a large number of nuts 64 are provided between the screw grooves 60a and 64a.
  • a ball 68 is accommodated so as to roll freely.
  • the nut 64 is supported by the housings 52a and 52b through two support bearings 69 and 69 so as to be rotatable and not movable in the axial direction.
  • the sleeve 67 that supports the screw shaft 60 so as not to rotate and to be movable in the axial direction is fastened to the bag hole 62 of the second housing 52b.
  • a female screw 62 a is formed in the bag hole 62 of the second housing 52 b
  • a male screw 67 b that is screwed into the female screw 62 a is formed on the outer periphery of the sleeve 67. Then, by moving the sleeve 67 toward the bottom of the bag hole 62, the female screw 62a and the male screw 67b are engaged, and the sleeve 67 is fastened to the second housing 52b.
  • the sleeve 67 is not in direct contact with the bottom of the second housing 52b, and is fastened through a cap 70. That is, the cap 70 is externally fitted to the end of the sleeve 67 and is integrally fitted to the bottom of the second housing 52b.
  • the screw shaft 60 does not directly collide with the bag hole 62 of the second housing 52b, and damage and wear of the second housing 52b are reduced, while at the same time reducing the weight and improving the durability and strength.
  • the reliability can be improved by increasing the reliability (see, for example, Patent Document 1).
  • the structure is improved in durability and strength so that it is safe even if the screw shaft 60 collides with the inner wall of the second housing 52b by inertia force, and the weight is reduced.
  • the cap 70 and the second housing 52b disposed at the end of the sleeve 67 require strength, and not only the material but also a certain level or more. Is required. This has been a hindrance to light weight and compactness.
  • An object of the present invention is to provide a ball screw and an electric actuator provided with the ball screw that are light and compact and that improve the reliability by avoiding a collision of a screw shaft.
  • the invention according to claim 1 of the present invention includes a screw shaft having a helical thread groove formed on the outer peripheral surface thereof, and is externally fitted to the screw shaft, and the screw is formed on the inner peripheral surface thereof.
  • the ball screw comprising: a nut in which a spiral thread groove corresponding to the thread groove of the shaft is formed; and a plurality of balls accommodated in a rolling path formed by the opposing screw grooves, the screw shaft And the screw groove of the nut has an arcuate thread groove facing the arcuate screw groove of the screw shaft. And a serrated thread groove facing the serrated thread groove of the screw shaft.
  • a screw shaft having a helical thread groove formed on the outer peripheral surface, and a nut that is fitted on the screw shaft and has a helical thread groove corresponding to the screw groove of the screw shaft formed on the inner peripheral surface.
  • a plurality of balls housed in a rolling path formed by opposing screw grooves wherein the screw shaft has a circular groove and a sawtooth-shaped screw groove.
  • the nut thread groove is composed of an arc-shaped thread groove facing the arc-shaped thread groove of the screw shaft and a serrated thread groove facing the saw-tooth thread groove of the screw shaft.
  • the arcuate thread groove of the screw shaft is formed in a circular arc shape whose cross section is a partial arc of a quarter of the circumference, and the sawtooth
  • the circular thread groove may be opposed to the arc-shaped thread groove in the axial direction, and the cross section may be formed in a trapezoidal shape.
  • the arc-shaped thread groove of the nut is formed in a circular arc shape whose cross section is a partial arc of a quarter of the circumference, and the sawtooth-shaped
  • the thread groove may face the arcuate thread groove in the axial direction, and the cross section may be formed in a trapezoidal shape.
  • the sawtooth-shaped thread groove of the nut extends in a tangential direction of the arc-shaped thread groove, and is formed on a flat surface having an inclination angle with respect to the vertical line of 0 ° to 20 °. If it is made, the axial direction of the thread groove can be made compact.
  • the thread groove of the nut has a circular arc-shaped cross section, and projects radially inward from the end of the thread groove, and the cross section is formed in a trapezoidal shape.
  • Two circular arcs having a radius of curvature larger than the radius of the ball. If it is formed in the Gothic arc shape which combined, it can hold
  • a housing an electric motor attached to the housing, a reduction mechanism that transmits the rotational force of the electric motor via a motor shaft, and the reduction mechanism are provided.
  • a ball screw for converting the rotational motion of the electric motor into a linear motion in the axial direction of the drive shaft.
  • the ball screw is rotatable through a support bearing mounted on the housing and cannot be moved in the axial direction.
  • a nut having a spiral thread groove formed on the inner periphery thereof, and a nut inserted into the nut via a number of balls, integrated with the drive shaft, and on the outer periphery thereof.
  • the electric actuator comprising a screw shaft that is formed in a spiral screw groove corresponding to the shaft and is supported so as to be non-rotatable and axially movable with respect to the housing
  • the ball screw according to any one of claims 1 to 5, wherein when a tensile load is applied to the screw shaft, there is no clearance between the nut and the arc-shaped screw groove of the screw shaft and the ball, A clearance is generated between the nut and the saw-tooth thread groove of the screw shaft, and the ball is in angular contact with both the arc-shaped thread grooves to form a ball screw, and reverse input is applied to the screw shaft.
  • the housing, the electric motor attached to the housing, the reduction mechanism that transmits the rotational force of the electric motor through the motor shaft, and the rotational axis of the electric motor through the reduction mechanism are driven.
  • the ball screw is converted to a linear motion in the axial direction of the screw, and the ball screw is supported by a support bearing mounted on the housing so as to be rotatable and non-movable in the axial direction.
  • a nut formed with a groove, and a nut inserted into the nut through a large number of balls, integrated coaxially with the drive shaft, and formed with a helical thread groove corresponding to the thread groove of the nut on the outer periphery;
  • An electric actuator comprising a screw shaft supported so as to be non-rotatable and movable in the axial direction, wherein the ball screw comprises the ball screw according to any one of claims 1 to 5.
  • a bag hole for accommodating the screw shaft is formed in the housing, and a steel sleeve is fastened through a threaded portion, and a shaft is formed on the inner periphery of the sleeve. If a concave groove extending in the direction is formed and a locking pin is implanted at the end of the screw shaft and engaged with the concave groove, the screw shaft cannot be rotated with respect to the housing and moved axially. It can be supported as possible.
  • the ball screw according to the present invention includes a screw shaft having a helical thread groove formed on the outer peripheral surface thereof, and a helical screw groove that is fitted on the screw shaft and corresponds to the screw groove of the screw shaft on the inner peripheral surface. And a plurality of balls accommodated in a rolling path formed by opposing screw grooves, wherein the thread groove of the screw shaft has an arc-shaped cross section. And a saw-toothed thread groove, and the thread groove of the nut is opposed to the arc-shaped thread groove facing the arc-shaped thread groove of the screw shaft and the saw-tooth thread groove of the screw shaft.
  • An electric actuator includes a housing, an electric motor attached to the housing, a reduction mechanism that transmits the rotational force of the electric motor via a motor shaft, and the electric actuator via the reduction mechanism.
  • a ball screw for converting the rotational motion of the motor into a linear motion in the axial direction of the drive shaft, and this ball screw is supported by a support bearing attached to the housing so as to be rotatable and not movable in the axial direction.
  • An electric actuator comprising a screw shaft formed with a spiral screw groove and supported so as to be non-rotatable and axially movable with respect to the housing.
  • a gap is generated between the nut and the sawtooth thread groove of the screw shaft, and the ball is in angular contact with both the arc-shaped screw grooves to form a ball screw, and the screw shaft is reversely input.
  • a load is applied, a clearance is generated between the nut and the arc-shaped thread groove of the screw shaft and the ball, and there is no clearance between the nut and the saw-tooth thread groove of the screw shaft. Since both screw grooves slide and come into a trapezoidal screw state, it is highly efficient for input loads and acts as a brake for external inputs.
  • FIG. 1 is a longitudinal cross-sectional view which shows the ball screw mechanism of FIG. 1
  • (b) is the principal part enlarged view of (a). It is a principal part enlarged view which shows the intermediate
  • A) is a principal part enlarged view which shows the modification of the nut of FIG. 2
  • (b) is a principal part enlarged view which shows the other modification of the nut of FIG. It is a longitudinal cross-sectional view which shows the conventional electric actuator.
  • An aluminum alloy housing An electric motor attached to the housing, a reduction mechanism that transmits the rotational force of the electric motor via a motor shaft, and the rotational movement of the electric motor is driven via the reduction mechanism
  • a ball screw mechanism for converting the shaft into a linear motion in the axial direction.
  • the ball screw mechanism is supported by a pair of support bearings mounted on the housing so as to be rotatable and non-movable in the axial direction.
  • the thread groove has a circumferential section.
  • An arcuate thread groove formed in a circular arc shape consisting of a partial arc of a fraction, and a serrated thread groove facing the arcuate thread groove in the axial direction and having a trapezoidal cross section
  • FIG. 1 is a longitudinal sectional view showing an embodiment of an electric actuator according to the present invention
  • FIG. 2 (a) is a longitudinal sectional view showing a ball screw mechanism of FIG. 1
  • FIG. 1 (b) is a main portion of FIG.
  • FIG. 3 is an enlarged view of a main part showing the intermediate gear part of FIG. 1
  • FIG. 4 is an enlarged view of a main part showing the sleeve of FIG. 1
  • FIG. 5 (a) is a load applied to the screw shaft of FIG.
  • FIG. 6B is an explanatory diagram showing the state of the screw shaft during reverse input load
  • FIG. 6A is an enlarged view of the main part showing a modification of the nut of FIG. ) Is an enlarged view of a main part showing another modified example of the nut of FIG. 2.
  • the electric actuator 1 meshes with a cylindrical housing 2, an electric motor M attached to the housing 2, and an input gear 3 attached to a motor shaft 3a of the electric motor M.
  • a reduction mechanism 6 comprising an intermediate gear 4 and an output gear 5 meshed with the intermediate gear 4, and a ball screw for converting the rotational movement of the electric motor M into the axial movement of the drive shaft 7 via the reduction mechanism 6.
  • the housing 2 is made of an aluminum alloy such as A6063TE or ADC12, and includes a first housing 2a and a second housing 2b abutted on the end face thereof, and is fixed integrally by a fixing bolt (not shown). .
  • An electric motor M is attached to the first housing 2a, and a through hole 11 and a bag hole 12 for accommodating the screw shaft 10 are formed in the first housing 2a and the second housing 2b. .
  • the motor shaft 3a of the electric motor M is rotatably supported by a rolling bearing 13 composed of a deep groove ball bearing mounted on the second housing 2b. Yes. Further, the output gear 5 that meshes with the intermediate gear 4 that is a spur gear is integrally fixed to the outer periphery of a nut 18 that constitutes a ball screw mechanism 8 described later via a key 14.
  • the drive shaft 7 is integrally formed with a screw shaft 10 constituting the ball screw mechanism 8, and a locking pin 15 is implanted at one end portion (right end portion in the figure) of the drive shaft 7.
  • a cylindrical sleeve 17 described later is fastened to the bag hole 12 of the second housing 2b.
  • channel 17a, 17a extended in an axial direction is formed in the position which the circumferential direction of the sleeve 17 opposes, The latching pin 15 of the screw shaft 10 is engaged with this groove 17a, 17a, and the screw shaft 10 is
  • the housing 2 is supported so as not to rotate and to be movable in the axial direction.
  • the ball screw mechanism 8 includes a screw shaft 10 and a nut 18 externally inserted through the ball 19 to the screw shaft 10 as shown in an enlarged view in FIG.
  • the screw shaft 10 has a spiral thread groove 9 formed on the outer periphery.
  • the nut 18 is extrapolated to the screw shaft 10, and a spiral screw groove 16 corresponding to the screw groove 9 of the screw shaft 10 is formed on the inner periphery.
  • a ball 19 is accommodated so as to roll freely.
  • the nut 18 is supported by the first and second housings 2a and 2b via the two support bearings 20 and 20 so as to be rotatable and non-movable in the axial direction.
  • Reference numeral 21 denotes a piece member that constitutes a circulation member by connecting the thread groove 16 of the nut 18, and a large number of balls 19 can be infinitely circulated by the piece member 21.
  • the nut 18 is formed in a cylindrical shape from case-hardened steel such as SCM415 or SCM420, and the thread groove 16 is formed by machining such as turning.
  • the surface is hardened in the range of 55 to 62 HRC by vacuum carburizing and quenching. Thereby, the buffing etc. for the scale removal after the heat treatment can be omitted, and the cost can be reduced.
  • the screw shaft 10 is formed in a cylindrical shape from medium carbon steel such as S55C or case-hardened steel such as SCM415 or SCM420, and the screw groove 9 is formed by machining such as turning.
  • the surface is hardened in the range of 55 to 62 HRC by induction hardening or carburizing hardening. Thereby, mass productivity improves and cost reduction can be achieved.
  • the thread groove 16 of the nut 18 and the thread groove 9 of the screw shaft 10 may be formed by rolling.
  • An output gear 5 constituting the speed reduction mechanism 6 is integrally fixed to the outer peripheral surface 18a of the nut 18, and two support bearings 20 and 20 are press-fitted on both sides of the output gear 5 via a predetermined shimiro. .
  • the two support bearings 20 and 20 are constituted by sealed deep groove ball bearings having shield plates 20a and 20a attached to both ends, and leakage of the lubricating grease enclosed in the bearings to the outside and from the outside This prevents wear powder from entering the bearing.
  • the support bearing 20 that rotatably supports the nut 18 is composed of deep groove ball bearings having the same specifications, and thus is loaded from the drive shaft 7 through the thrust load and the output gear 5 described above. Both radial loads can be applied, and confirmation work for preventing misassembly during assembly can be simplified, and assembling workability can be improved.
  • the deep groove ball bearings having the same specifications refer to bearings having the same inner diameter, outer diameter, width dimension, rolling element size, number, bearing internal clearance, and the like.
  • one of the pair of support bearings 20, 20 (the left side in the figure) is mounted on the first housing 2a via a washer 27 made of a ring-shaped elastic member.
  • This washer 27 is formed by press working from an austenitic stainless steel plate (JIS standard SUS304 type or the like) having high strength and wear resistance, or a rust-proof cold rolled steel plate (JIS standard SPCC type or the like). It consists of a wave washer.
  • the inner diameter D is formed larger than the outer diameter d of the inner ring 20 b of the support bearing 20.
  • the axial backlash of the pair of support bearings 20 and 20 can be eliminated, smooth rotation performance can be obtained, and the inner ring that the washer 27 abuts only on the outer ring of the support bearing 20 and becomes a rotating ring. Therefore, even if a reverse thrust load is generated and the nut 18 is pressed against the first housing 2a, the end surface of the inner ring 20b of the support bearing 20 comes into contact with the first housing 2a and the frictional force increases. Can be prevented, and the locked state can be prevented.
  • the intermediate gear 4 constituting the speed reduction mechanism 6 is rotatably supported on a gear shaft 22 implanted in the first and second housings 2 a and 2 b via a rolling bearing 23.
  • the end portions of the gear shaft 22 for example, when press-fitting the end portion on the first housing 2a side, the end portion on the second housing 2b side is set to be a clearance fit, thereby making misalignment (assembly error). Allowing smooth rotation performance can be ensured.
  • the rolling bearing 23 includes an outer ring 24 made of a steel plate press-fitted into the inner diameter 4 a of the intermediate gear 4, and a plurality of needle rollers 26 accommodated in the outer ring 24 via a cage 25 so as to be freely rollable. And so-called shell-type needle roller bearings. Thereby, the availability of a bearing is high and cost reduction can be achieved.
  • the washer 28 is a flat washer formed by pressing from an austenitic stainless steel plate having high strength and high wear resistance, or a cold-rolled steel plate treated with rust prevention.
  • a thermoplastic synthetic resin such as PA (polyamide) 66 filled with a predetermined amount of a fibrous reinforcing material such as brass, sintered metal, or GF (glass fiber). May be.
  • the width of the rolling bearing 23 is set smaller than the tooth width of the intermediate gear 4. Therefore, wear and deformation of the bearing side surface due to friction can be prevented, and smooth rotation performance can be obtained.
  • the sleeve 17 that supports the screw shaft 10 so as not to rotate and to be movable in the axial direction is fastened to the bag hole 12 of the second housing 2 b.
  • a female screw 12 a is formed in the bag hole 12 of the second housing 2 b
  • a male screw 17 b that is screwed into the female screw 12 a is formed on the outer periphery of the sleeve 17. Then, when the sleeve 17 is screwed (advanced while rotating) toward the bottom 12b of the bag hole 12, the female screw 12a and the male screw 17b are engaged, and the sleeve 17 is fastened to the second housing 2b.
  • the sleeve 17 is formed in a cylindrical shape by cold forging from medium carbon steel such as S55C or case-hardened steel such as SCM415 or SCM420, and concave grooves 17a and 17a extending in the axial direction are formed at opposing positions on the inner periphery.
  • a metal plating such as electroless nickel plating is applied to the surface of the groove 17a.
  • the surface of the locking pin 15 that engages with the concave groove 17a is also plated with metal such as hard chrome plating. Thereby, abrasion resistance improves and abrasion can be suppressed over a long period of time.
  • examples of the metal plating include zinc plating, unichrome plating, chromate plating, nickel plating, chrome plating, and Kanigen plating.
  • the metal plating is preferably made of different materials so that the concave groove 17a and the locking pin 15 can be prevented from sticking to each other during sliding.
  • a plurality of concave portions 29 are formed on the end surface of the second housing 2b at equal intervals in the circumferential direction, and the outer diameter portion of the end surface of the sleeve 17 is plastically deformed toward the concave portions 29.
  • the sleeve 17 is prevented from rotating by the crimped portion 30. Thereby, it is possible to prevent the threaded portion of the sleeve 17 from loosening due to vibration during operation, and to improve reliability.
  • the female screw 12a of the second housing 2b and the male screw 17b of the sleeve 17 are provided near the bottom of the bag hole 12.
  • the caulking portion 30 causes the screw to tighten. Looseness can be prevented, and reliability is improved.
  • the screw shaft 10 and the thread grooves 9 and 16 of the nut 18 are formed in different cross-sectional shapes on the left and right.
  • the screw groove 9 of the screw shaft 10 includes an arcuate screw groove 9a that forms a normal ball screw and a saw-toothed screw groove 9b that forms a trapezoidal screw.
  • the screw groove 16 of the nut 18 includes an arcuate screw groove 16a that faces the screw groove 9a of the screw shaft 10 and a sawtooth screw groove 16b that faces the sawtooth screw groove 9b.
  • the thread grooves 9a and 16a forming the ball screw are formed in a circular arc shape having a partial arc of a quarter or two of the circumference.
  • the thread grooves 9b and 16b forming the trapezoidal screw are opposed to the arc-shaped thread grooves 9a and 16a in the axial direction, and a cross section composed of a flat surface having an inclination angle with respect to the perpendicular is 0 ° to 20 ° is formed in a trapezoidal shape.
  • the input load becomes highly efficient, and also acts as a brake for the external input.
  • the screw grooves 9b and 16b are insensitive to the load, and cannot be controlled due to a system error or the like.
  • the shaft end (here, the right end surface) of the screw shaft 10 collides with the bottom surface 12b of the bag hole 12 of the second housing 2b. This can be prevented (see FIG. 1). Therefore, it is possible to provide the electric actuator 1 which is improved in reliability by avoiding the collision of the screw shaft 10 and reduced in weight and size by reducing the thickness of the second housing 2b.
  • FIG. 6 shows a modification of the nut 18 described above.
  • the nut 31 shown in (a) has a spiral thread groove 32 formed on the inner periphery, and the thread groove 32 includes a thread groove 32a having an arcuate cross section forming a normal ball screw, and the thread groove 32a.
  • a sawtooth-shaped thread groove 16b that protrudes radially inward from the end and forms a trapezoidal screw is formed.
  • the arc-shaped thread groove 32a is formed by a semicircle having a half of the circumference, and the cross-sectional shape is formed in a Gothic arc shape combining two arcs having a radius of curvature slightly larger than the radius of the ball 19. Has been.
  • the thread groove 32a may have a circular arc shape formed of a single arc.
  • the nut 33 shown in (b) has a spiral thread groove 34 formed on the inner periphery, and the thread groove 34 is formed from a thread groove 16a having a circular arc cross section forming a normal ball screw, and the thread groove 16a. It has a sawtooth-shaped thread groove 34a that protrudes radially inward and forms a trapezoidal screw.
  • the serrated thread groove 34a has one tooth surface Ff (left side in the figure) facing the arc-shaped thread groove 16a in the axial direction, and the other tooth surface Bf (right side in the figure) is the arc-shaped thread groove 16a. It is formed in a flat surface extending in the tangential direction and having an inclination angle with respect to the perpendicular of 0 ° to 20 °. As a result, the axial direction of the thread groove 34 can be made compact.
  • An electric actuator includes a ball screw mechanism that is used in a drive unit of a general industrial electric motor, an automobile, or the like, and that converts a rotational input from an electric motor into a linear motion of a drive shaft via the ball screw mechanism. Applicable to electric actuators.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Transmission Devices (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Abstract

L'invention concerne une vis sphérique et un actionneur à commande électrique doté de la vis sphérique, qui ont chacun un poids réduit par réduction de l'épaisseur de paroi d'un boîtier et qui ont chacun une fiabilité accrue obtenue en évitant l'impact d'un arbre fileté. Un actionneur à commande électrique 1 est pourvu d'un arbre fileté 10 supporté de manière à ne pas pouvoir tourner par rapport à un boîtier 2 et de manière à être mobile axialement. Des rainures de filetage 9, 16 comprennent des rainures de filetage en forme d'arc de cercle 9a,16a et des rainures de filetage en forme de dents de scie 9b, 16b. Lorsqu'une charge de traction est appliquée à l'arbre fileté 10, les espaces entre les rainures de filetage en forme d'arc de cercle 9a, 16a et des billes 19 disparaissent et des espaces apparaissent entre les rainures de filetage en forme de dents de scie 9b, 16b. En conséquence, les rainures de filetage en forme d'arc de cercle 16a, 9a et les billes 19 viennent en contact oblique les unes avec les autres pour obtenir un état de vis sphérique. Lorsqu'une entrée dans la direction opposée est appliquée, des espaces apparaissent entre les rainures de filetage en forme d'arc de cercle 16a, 9a et les billes 19 et les espaces entre les rainures de filetage en forme de dents de scie 16b, 9b disparaissent. En conséquence, les rainures de filetage en forme de dents de scie 16b, 9b viennent en contact coulissant les unes avec les autres pour obtenir un état de filetage trapézoïdal.
PCT/JP2016/070900 2015-07-15 2016-07-14 Vis sphérique et actionneur à commande électrique doté de celle-ci WO2017010553A1 (fr)

Applications Claiming Priority (2)

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JP2015-141050 2015-07-15
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Publication number Priority date Publication date Assignee Title
EP3575635A1 (fr) * 2018-05-30 2019-12-04 The Boeing Company Actionneur à vis, aéronef comprenant un actionneur à vis et procédé de levage d'une charge
CN110588955A (zh) * 2019-09-03 2019-12-20 中国空空导弹研究院 一种滚珠丝杠副旋转作动器装置
WO2021020263A1 (fr) * 2019-08-01 2021-02-04 国立大学法人東海国立大学機構 Unité de vis à rouleaux

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JPS60231064A (ja) * 1984-04-26 1985-11-16 Kuroda Precision Ind Ltd ボ−ルねじ
JP2002227957A (ja) * 2001-01-31 2002-08-14 Aida Eng Ltd 複合ねじ
JP2014043905A (ja) * 2012-08-27 2014-03-13 Ntn Corp 電動リニアアクチュエータ

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JPS60231064A (ja) * 1984-04-26 1985-11-16 Kuroda Precision Ind Ltd ボ−ルねじ
JP2002227957A (ja) * 2001-01-31 2002-08-14 Aida Eng Ltd 複合ねじ
JP2014043905A (ja) * 2012-08-27 2014-03-13 Ntn Corp 電動リニアアクチュエータ

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3575635A1 (fr) * 2018-05-30 2019-12-04 The Boeing Company Actionneur à vis, aéronef comprenant un actionneur à vis et procédé de levage d'une charge
US10801594B2 (en) 2018-05-30 2020-10-13 The Boeing Company Screw actuator, aircraft comprising a screw actuator, and method of lifting a load
WO2021020263A1 (fr) * 2019-08-01 2021-02-04 国立大学法人東海国立大学機構 Unité de vis à rouleaux
JP7525905B2 (ja) 2019-08-01 2024-07-31 国立大学法人東海国立大学機構 転動体ねじ装置
CN110588955A (zh) * 2019-09-03 2019-12-20 中国空空导弹研究院 一种滚珠丝杠副旋转作动器装置
CN110588955B (zh) * 2019-09-03 2024-04-09 中国空空导弹研究院 一种滚珠丝杠副旋转作动器装置

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