WO2018051873A1 - Actionneur électrique - Google Patents

Actionneur électrique Download PDF

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Publication number
WO2018051873A1
WO2018051873A1 PCT/JP2017/032225 JP2017032225W WO2018051873A1 WO 2018051873 A1 WO2018051873 A1 WO 2018051873A1 JP 2017032225 W JP2017032225 W JP 2017032225W WO 2018051873 A1 WO2018051873 A1 WO 2018051873A1
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WO
WIPO (PCT)
Prior art keywords
case
ball screw
electric actuator
diameter
motor
Prior art date
Application number
PCT/JP2017/032225
Other languages
English (en)
Japanese (ja)
Inventor
辰徳 清水
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 WO2018051873A1 publication Critical patent/WO2018051873A1/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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C31/00—Bearings for parts which both rotate and move linearly
    • F16C31/04—Ball or roller bearings
    • 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
    • F16H2025/2062—Arrangements for driving the actuator
    • F16H2025/2075—Coaxial drive motors
    • 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
    • F16H2025/2062—Arrangements for driving the actuator
    • F16H2025/2087—Arrangements for driving the actuator using planetary gears
    • 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
    • F16H25/24—Elements essential to such mechanisms, e.g. screws, nuts
    • F16H25/2418—Screw seals, wipers, scrapers or the like

Definitions

  • the present invention relates to an electric actuator.
  • Patent Document 1 a configuration in which the motor and the ball screw mechanism are arranged in series is preferable (for example, Patent Document 1). See). In such a configuration, in order to move the screw shaft of the ball screw mechanism in the axial direction, it is conceivable to directly connect the motor and the nut of the ball screw mechanism and to support the nut rotatably with a bearing ( For example, see Patent Document 2).
  • the rolling bearings that support the nut in a rotatable manner are spaced apart in the center line direction and arranged at two locations.
  • the structure which does is preferable.
  • the actuator described in Patent Document 2 may have a structure in which the screw shaft protrudes on both sides in the center line direction of the nut, and the case accommodating the ball screw mechanism including the nut is divided into a plurality of forms. I'm taking it. Therefore, it will be in the state where two rolling bearings which support a nut rotatably are attached to separate cases.
  • the present specification solves the problem of providing an electric actuator capable of obtaining excellent power transmission efficiency by suppressing as much as possible the misalignment and inclination of the rotating portion with respect to the linear motion portion. It should be a technical issue to be done.
  • the actuator includes a motor, a motion conversion mechanism that converts the rotational motion generated by driving the motor into a linear motion, and a case that houses the motion conversion mechanism.
  • the rotating part is supported by two bearings spaced apart in the center line direction, and the two bearings It is characterized by the fact that it is attached to a cylindrical surface having a constant inner diameter provided around the circumference.
  • the rotating portion of the motion conversion mechanism is supported by the two bearings, and the two bearings have the same inner diameter dimension provided on the inner periphery of the case housing the motion conversion mechanism. It was made to attach to a cylindrical surface. In this way, by providing a common mounting surface for the two bearings on the inner periphery of one case, it is possible to avoid being affected by assembly errors and the like compared to the case where the bearings are mounted across a plurality of cases. . Furthermore, since the mounting surface common to the two bearings is an equal-diameter cylindrical surface having a constant inner diameter dimension, for example, compared to the case where two surfaces having different inner diameter dimensions through a step are used as the bearing mounting surfaces, respectively.
  • the shape accuracy (processing accuracy) of the mounting surface can be easily increased. Therefore, by matching the rotation center of each bearing with high accuracy, it is possible to prevent as much as possible the situation where the rotation center of the rotating part supported by these bearings is shifted or inclined with respect to the center line of the linear motion part, Or the shift
  • the case may integrally have a metallic cylindrical member, and an equal-diameter cylindrical surface may be provided on the inner periphery of the cylindrical member.
  • This type of actuator case usually cannot be made into a simple cylindrical shape to accommodate a motion conversion mechanism such as a ball screw mechanism, and must have a complicated shape other than the cylindrical shape.
  • the cylindrical member is provided with an equal-diameter cylindrical surface as the mounting surface, and this cylindrical member is provided integrally with the case, the mounting surface of the bearing is not affected by the shape of the case. It can be finished into an isometric cylindrical shape.
  • this cylindrical member made of metal, it is possible to maintain the shape accuracy of the mounting surface (equal diameter cylindrical surface) after mounting the bearing while minimizing deformation due to press-fitting and the like.
  • the material of the case main body can be made of a resin excellent in mass productivity. Therefore, it is suitable not only for positional accuracy but also for processing cost.
  • the case has a small-diameter portion whose inner diameter is smaller than that of the equal-diameter cylindrical surface on one side in the axial direction of the equal-diameter cylindrical surface, and is linearly moved on the inner periphery of the small-diameter portion.
  • a sliding surface on which the part can slide may be provided.
  • the support portion (bearing) of the rotating portion and the linear motion portion of one part (case) are provided.
  • a support part (sliding surface) can be provided.
  • the electric actuator according to the present invention has an end surface support portion that protrudes radially inward from one axial side of the cylindrical member and supports the axial end surface of the bearing. It may be a thing.
  • the rotating part Since the rotating part is supported by two bearings, the movement of the rotating part in the axial direction (direction along the rotation center line) is restricted by providing an end face support part that supports at least one of the bearings in the axial direction. be able to. At this time, by providing the end face support portion of the bearing together with the equal-diameter cylindrical surface in one component (cylindrical member), not only the radial positioning of the bearing but also the axial positioning can be accurately performed. Therefore, it is possible to improve the positional accuracy in the radial direction and the axial direction of the rotating portion supported by the bearing.
  • the electric actuator according to the present invention has a small diameter portion constituted by a sintered bearing made of sintered metal, and the case uses both the slide bearing and the cylindrical member as insert parts. It may be a resin molded product.
  • the sliding lubricity between the linear motion portion and the linear motion portion is further improved by, for example, impregnating the sliding bearing with a lubricant such as lubricating oil or grease. be able to. Therefore, it is possible to further reduce the sliding resistance.
  • the shape accuracy here, the shape accuracy means difficulty of deformation with respect to a load, that is, rigidity.
  • only a necessary portion can be made of metal, and the remaining portion can be made of resin. Therefore, it is possible to reduce the weight of the entire case that can exhibit the above-described excellent performance.
  • the center line between the sliding surface and the equal-diameter cylindrical surface can be easily and accurately matched by accurately positioning each insert component on the insert mold.
  • the sliding surface includes one or two or more flat surfaces that form part of the circumferential direction, and a partial cylindrical surface that is connected to the flat surface and forms the remainder of the circumferential direction.
  • the region that slides at least with the sliding surface of the outer peripheral surface of the linear motion portion has a shape corresponding to the flat surface and the partial cylindrical surface that constitute the sliding surface. Also good.
  • the shape of the sliding surface is a non-circular cross section
  • the shape of the region that slides with the sliding surface of the outer peripheral surface of the linear motion portion is a shape corresponding to the sliding surface
  • the electric actuator of the present invention it is possible to obtain excellent power transmission efficiency by suppressing as much as possible the misalignment and inclination of the rotating portion with respect to the linear motion portion.
  • FIG. 2 is a partially exploded perspective view of the electric actuator shown in FIG. 1.
  • FIG. 2 is a cross-sectional view of the electric actuator as seen from the direction of an arrow A, taken along the line AA in FIG.
  • FIG. 2 is a partially exploded perspective view of the electric actuator shown in FIG. 1.
  • FIG. 3 is a cross-sectional view of the electric actuator as seen from the direction of an arrow B along a cross section along line BB in FIG. It is a disassembled perspective view of the ball screw shaft in the state where the permanent magnet was attached.
  • FIG. 1 shows a longitudinal sectional view of the electric actuator according to the first embodiment of the present invention.
  • 2 is an external perspective view of the electric actuator shown in FIG. 1
  • FIG. 3 is a partially exploded perspective view of the electric actuator shown in FIG.
  • the electric actuator 1 includes a drive unit 2 that generates a driving force, a motion conversion mechanism unit 3 that converts a rotational motion from the drive unit 2 into a linear motion, and a drive unit 2.
  • a driving force transmission unit 4 that transmits a driving force to the motion conversion mechanism unit 3, a motion conversion mechanism support unit 5 that supports the motion conversion mechanism unit 3, and an operation unit 6 that outputs the motion of the motion conversion mechanism unit 3 Prepare.
  • the drive unit 2 has a drive force generation motor (drive motor 7), and the drive force transmission unit 4 transmits the drive force received from the drive unit 2 to the motion conversion mechanism unit 3. It has a speed reduction mechanism 8 as a force transmission mechanism.
  • each element of the electric actuator 1 described above has a plurality of cases constituting the appearance of the electric actuator 1 (see FIG. 2).
  • the drive unit 2 has a motor cover 9 as a motor case that houses the drive motor 7, and the drive force transmission unit 4 is a reduction mechanism unit 8 (more precisely, a part of the reduction mechanism unit 8).
  • the motion conversion mechanism unit 3 includes a ball screw case 12 that houses a ball screw mechanism 11 as a motion conversion mechanism.
  • the ball screw case 12 also serves as a case for housing the bearings 13 and 14 constituting the motion conversion mechanism support portion 5.
  • the drive unit 2, the drive force transmission unit 4, and the motion conversion mechanism unit 3 are configured to be connected and separated together with the case.
  • the drive unit 2 mainly includes a drive motor 7 such as a DC motor and a motor cover 9 that houses the drive motor 7 (see FIG. 1).
  • the motor cover 9 includes a bottomed cylindrical cover main body 15 that covers the periphery of the driving motor 7, and a flange portion 16 that protrudes radially outward from one end opening side (left side in FIG. 1) of the cover main body 15.
  • the driving motor 7 is inserted into the cover body 15 from one end opening side.
  • the inner peripheral surface 15 a of the cover main body 15 is tapered from one end opening side to the back side, and when the driving motor 7 is inserted into the cover main body 15, The rear side in the insertion direction is configured to come into contact with the inner peripheral surface 15a of the cover body 15 while avoiding contact with the surface.
  • a motor fitting portion 17 to be described later is fitted with a predetermined fitting (for example, inlay) on the projection portion 7a on the output side (left side in FIG. 1) of the driving motor 7,
  • the drive motor 7 is supported by the cover main body 15 and the motor fitting portion 17 in a state of being accommodated in the cover main body 15.
  • an O-ring 18 is interposed between the drive motor 7 and the inner bottom surface 15b of the cover main body 15, and the output shaft of the drive motor 7 is suppressed while suppressing the backlash of the motor in the axial direction. The outflow of grease etc. from 7b is prevented.
  • the drive motor 7 is provided with a pair of terminals 19 and 19 for connecting the drive motor 7 to a power source.
  • One end portion 19a of each terminal 19 is connected by being inserted into the terminal insertion groove 7c of the drive motor 7, and the other end portion 19b is crimped by crimping an electric wire (not shown) so as to be electrically connected to an external power source.
  • the pair of terminals 19 and 19 are held by a terminal holder 20 that can be fitted to the outer periphery of the drive motor 7 (see FIGS. 3 and 4), thereby preventing the drive motor 7 from being detached.
  • a grommet 21 is fitted in a hole 15c provided in the bottom of the cover body 15 (see FIGS. 1 and 3), and is illustrated through a pair of holes 21a and 21a provided in the grommet 21. It is possible to pull out the wires that are not used.
  • the driving force transmission unit 4 mainly includes a reduction mechanism unit 8 as a driving force transmission mechanism and a reduction mechanism case 10 that houses the reduction mechanism unit 8.
  • the speed reduction mechanism unit 8 includes a planetary gear speed reduction mechanism 22 including a plurality of gears, for example. The detailed configuration of the planetary gear speed reduction mechanism 22 will be described later.
  • the speed reduction mechanism case 10 protrudes from the case body 23 to one end side in the axial direction (left side in FIG. 1) and fits with the ball screw case 12.
  • the screw case fitting portion 24 and a projecting portion 7a of the driving motor 7 projecting inward in the radial direction from the other axial end side (right side in FIG. 1) of the case main body 23 with a predetermined fit (for example, inlay).
  • the motor fitting part 17 which fits is integrally included.
  • the speed reduction mechanism case 10 integrally has a flange portion 25 extending radially outward from the case body 23.
  • the flange portions 26 of the ball screw case 12 are connected to each other by, for example, bolts 27 (see FIG. 3) in a state where they are overlapped with each other.
  • O-rings 28 and 29 may be interposed between the flange portions 16, 25 and 26.
  • the motion conversion mechanism unit 3 includes a ball screw mechanism 11 as a motion conversion mechanism and a ball screw case 12 that accommodates the ball screw mechanism 11 in the present embodiment.
  • the ball screw mechanism 11 includes a ball screw nut 30 as a rotating part, a ball screw shaft 31 as a linearly movable part (that is, a linearly acting part), a large number of balls 32, and a top 33 as a circulating member. It consists of Helical grooves 30a and 31a are formed on the inner peripheral surface of the ball screw nut 30 and the outer peripheral surface of the ball screw shaft 31, respectively. Balls 32 are filled between the spiral grooves 30a and 31a, and a top 33 is incorporated, whereby two rows of balls 32 circulate.
  • the ball screw nut 30 receives the driving force generated by the driving motor 7 and rotates in either the forward or reverse direction.
  • the rotation of the ball screw shaft 31 is restricted by a sliding surface 34 (a left end portion of the ball screw case 12 in FIG. 1) as a rotation preventing mechanism described later.
  • a sliding surface 34 a left end portion of the ball screw case 12 in FIG. 1 as a rotation preventing mechanism described later.
  • FIG. 1 shows a state in which the ball screw shaft 31 is disposed at an initial position which is most retracted to the right side of the drawing.
  • the ball screw shaft 31 is arranged so as to be parallel to the output shaft 7 b of the driving motor 7, and so that the center lines of the shafts 31 and 7 b coincide with each other, and through the driving force transmission unit 4. 7 is converted into a linear motion in the axial direction parallel to the output shaft 7b by the ball screw shaft 31.
  • the forward end portion (left end portion in FIG. 1) of the ball screw shaft 31 functions as an operation portion (actuator head) 6 that operates an operation target.
  • the ball screw case 12 has a generally cylindrical shape (see FIG. 2), and is located on the case main body 35 and one end side in the axial direction of the case main body 35 (on the left side in FIG. 1). And a flange portion 26 located on the other end side in the axial direction (right side in FIG. 1) of the case main body 35, for example. Further, between the ball screw case 12 and the ball screw nut 30 configured as described above, two bearings 13 and 14 are disposed apart from each other in the center line direction of the case main body 35 (left and right direction in FIG. 1). The ball screw nut 30 is rotatably supported by these two bearings 13 and 14.
  • the two bearings 13 and 14 are both rolling bearings, and both the outer rings 13a and 14a are provided on a constant-diameter cylindrical surface 37 having a constant inner diameter dimension provided on the inner periphery of the case body 35. It is attached by fitting (see FIG. 1).
  • the screw case fitting portion 24 protruding to one end side in the axial direction (left side in FIG. 1) of the speed reduction mechanism case 10 is attached to the equal-diameter cylindrical surface 37 with a predetermined fit (for example, inlay). .
  • a predetermined fit for example, inlay
  • both the screw case fitting portion 24 and the two bearings 13 and 14 are fixed to the ball screw case 12 in a state of being centered on the basis of the equal-diameter cylindrical surface 37.
  • the screw case fitting portion 24 is automatically attached by attaching the speed reduction mechanism case 10 to the ball screw case 12 by, for example, bolt fastening between the flange portions 25 and 26 (see FIG. 3).
  • the ball screw case 12 integrally has a metallic cylindrical member 38.
  • the equal-diameter cylindrical surface 37 is configured by the inner peripheral surface of the tubular member 38. Therefore, the inner peripheral surface of the cylindrical member 38 is in a state where the cylindricity and the like are finished with high accuracy.
  • the cylindrical member 38 integrally has an end surface support portion 39 that protrudes inward in the radial direction from one axial end side (left side in FIG. 1) of the equal-diameter cylindrical surface 37.
  • the inner side surface 39a of the end surface support portion 39 is exposed in the inner space of the ball screw case 12, and the inner side surface 39a is one end side in the axial direction of the cylindrical member 38 of the two bearings 13 and 14 (FIG. 1). In other words, it is in contact with the bearing 13 located on the left side). Therefore, the bearing 13 is positioned in the axial direction with reference to the inner side surface 39a, and the bearing 13 is supported in the axial direction by the end surface support portion 39.
  • the ball screw shaft 31 as a linear motion portion is inserted into the small diameter portion 36 (see FIG. 1).
  • a sliding surface 34 on which the ball screw shaft 31 can slide is provided on the inner periphery of the small diameter portion 36.
  • a sliding bearing 40 made of sintered metal is provided on the inner periphery of the tip of the small diameter portion 36, and a sliding surface 34 is formed on the inner periphery of the sliding bearing 40.
  • the sliding bearing 40 may be impregnated with a lubricant such as grease or lubricating oil so that the lubricant is continuously supplied to the sliding surface 34.
  • a rotation preventing mechanism for the ball screw shaft 31 is provided on the sliding surface 34.
  • the sliding surface 34 is composed of one flat surface 34 a forming a part in the circumferential direction and a partial cylinder connected to the flat surface 34 a and forming the remainder in the circumferential direction. It is comprised by the surface 34b.
  • at least the sliding area 31 b that slides with the sliding surface 34 of the outer peripheral surface of the ball screw shaft 31 is a flat surface corresponding to the flat surface 34 a constituting the sliding surface 34. It is comprised by the surface part 31b1 and the partial cylindrical surface part 31b2 corresponding to the partial cylindrical surface 34b.
  • the dimensions of the surfaces 31b1 and 34a are such that the flat surface portion 31b1 of the ball screw shaft 31 is in contact (engaged) with the flat surface 34a at least at its maximum outer diameter portion (boundary portion with the partial cylindrical surface portion 31b2). Is set.
  • the flat surface 34 a plays a role of regulating the rotation around the center line of the ball screw shaft 31. 1 and 5, a member denoted by reference numeral 41 is a retaining ring, and is attached to a predetermined position in the axial direction of the ball screw shaft 31 to thereby have a member having a sliding surface 34 (here, a sliding bearing 40) and an end surface. By abutting each other, it plays a role of regulating the movement of the ball screw shaft 31 in the axial direction.
  • the ball screw case 12 when the ball screw case 12 includes the cylindrical member 38 and the slide bearing 40, the ball screw case 12 is, for example, a resin molded product using both the cylindrical member 38 and the slide bearing 40 as insert parts. It is possible. At this time, for the purpose of accurately positioning the cylindrical member 38 in the axial direction, for example, as shown in FIGS. 1 and 5, a positioning hole 12 a of the cylindrical member 38 may be provided in the resin portion of the ball screw case 12. Good.
  • the ball screw nut 30 has a large-diameter portion 30b at an intermediate position in the axial direction.
  • Two bearings (rolling bearings) 13 and 14 are attached.
  • a bearing 13 having both an outer ring 13a and an inner ring 13b is used as the bearing 13 on the side closer to the operation unit 6 (the side far from the driving motor 7), and the side farther from the operation unit 6 (for driving)
  • a bearing 14 having only an outer ring 14 a and no inner ring is used.
  • the bearing 14 is not limited to this, and a bearing 14 having both an outer ring and an inner ring is used. May be.
  • the bearing 13 on the side close to the operation portion 6 is axially moved by the end surface support portion 39 of the tubular member 38 via the plate-like elastic member 42 as shown in FIGS. It is supported.
  • this plate-like elastic member 42 for example, a wave washer can be used.
  • the screw case fitting portion 24 of the speed reduction mechanism case 10 is fitted to the equal-diameter cylindrical surface 37 of the ball screw case 12 as shown in FIG.
  • the screw case fitting portion 24 is in a state where the bearing 14 on the side close to the drive motor 7 is pressed in the axial direction.
  • 1 and 5 is a spacer washer, which serves to prevent interference between the plate-like elastic member 42 and the inner ring 13b of the bearing 13.
  • a boot 44 for preventing foreign matter from entering the ball screw case 12 is attached between the small diameter portion 36 and the ball screw shaft 31 (see FIG. 1).
  • the boot 44 is made of resin or rubber, and includes a large-diameter end portion 44a and a small-diameter end portion 44b, and a bellows portion 44c that extends and contracts in the axial direction by connecting the large-diameter end portion 44a and the small-diameter end portion 44b. Yes.
  • the large-diameter end portion 44a is fastened and fixed to the attachment portion of the outer peripheral surface of the small-diameter portion 36 by the first boot band 45, and the small-diameter end portion 44b is fixed to the attachment portion of the outer peripheral surface of the ball screw shaft 31 by the second boot band 46. Tightened and fixed.
  • a boot cover 47 that covers the boot 44 is disposed around the boot 44 (see FIGS. 1 and 5).
  • the boot cover 47 is attached to, for example, the ball screw case 12 adjacent in the axial direction.
  • illustration is abbreviate
  • FIG. 1 is an exploded perspective view of the planetary gear speed reduction mechanism 22
  • FIG. 6 is a cross-sectional view of the cross section taken along line BB of FIG.
  • the planetary gear reduction mechanism 22 includes a ring gear 48, a sun gear 49, a plurality of planetary gears 50, a planetary gear carrier 51, and a planetary gear holder 52.
  • the ring gear 48 may be manufactured separately from the ball screw case 12, for example, and then fixed to the ball screw case 12. However, when the cylindrical member 38 or the slide bearing 40 is used as an insert part as described above, a metal ring gear 48 may be integrally formed with the ball screw case 12 as an insert part, like the cylindrical member 38 or the like. Of course, if there is no problem in terms of rigidity, the ring gear 48 may be formed of resin as a part of the resin portion of the ball screw case 12.
  • a sun gear 49 is arranged in the center of the ring gear 48, and the output shaft 7b of the drive motor 7 is connected to the sun gear 49 by press fitting (see FIG. 1).
  • Each planetary gear 50 is disposed between the ring gear 48 and the sun gear 49 so as to mesh with the ring gear 48 and the sun gear 49 (see FIG. 6).
  • Each planetary gear 50 is rotatably supported by a planetary gear carrier 51 and a planetary gear holder 52.
  • the planetary gear carrier 51 has a cylindrical portion 51a on the outermost diameter side (see FIG. 3), and this cylindrical portion 51a is connected to the outer peripheral surface of the ball screw nut 30 by press fitting or the like (see FIG. 1). reference).
  • the driving force from the driving motor 7 can be transmitted as a rotational force to the ball screw nut 30 via the planetary gear carrier 51.
  • the electric actuator 1 is equipped with a position detection device for detecting the position of the operation unit 6 provided on the ball screw shaft 31 in the linear movement direction (stroke direction). As shown in FIGS. 1 and 7, the position detection device is provided at a predetermined position of a permanent magnet 53 (see FIG. 1) as a sensor target provided at a predetermined position of the ball screw shaft 31 and a boot cover 47. And a magnetic sensor 54 as a position detection sensor.
  • the magnetic sensor 54 is formed integrally with the sensor substrate 55 as shown in FIGS. 1 and 5, and the sensor substrate 55 is fixed to the sensor case 57 by an appropriate connecting member 56. Then, the sensor assembly 58 formed by attaching the sensor substrate 55 to the sensor case 57 is attached to a sensor attachment portion 47a provided at a predetermined position in the circumferential direction of the boot cover 47 by fitting or the like, so that the magnetic sensor 54 is booted.
  • the cover 47 is installed at a predetermined position in the circumferential direction and faces the permanent magnet 53 via the boot 44 and the boot cover 47 (see FIG. 1). In this case, the magnetic sensor 54 is covered with the boot cover 47 and the sensor case 57 (see FIG. 1).
  • Arbitrary types can be used as the magnetic sensor 54.
  • a magnetic sensor of a type capable of detecting the direction and magnitude of a magnetic field using the Hall effect such as a Hall IC or a linear Hall IC, can be suitably used.
  • the sensor case 57 and the boot cover 47 that cover the periphery of the magnetic sensor 54 are preferably formed of a nonmagnetic material, for example, a resin.
  • the permanent magnet 53 serving as the sensor target is disposed on the ball screw shaft 31 serving as the movable portion. Specifically, as shown in FIG. 1, a permanent magnet 53 is disposed between the operation unit 6 and the spiral groove 31 a of the ball screw shaft 31.
  • FIG. 7 is an exploded perspective view of the ball screw shaft 31 in a state where the sensor target unit 59 including the permanent magnet 53 is attached. As shown in FIG. 7, a notch 31c is formed at a predetermined position in the axial direction of the ball screw shaft 31, and a sensor target unit 59 is attached to the notch 31c.
  • the sensor target unit 59 includes a permanent magnet 53, and a first magnet holder 60 and a second magnet holder 61 that hold the permanent magnet 53.
  • the first magnet holder 60 is provided with a pair or a plurality of pairs (two pairs in the illustrated example) of fitting claws 60 a that can be fitted into the notch 31 c of the ball screw shaft 31.
  • a housing portion 60b capable of housing the permanent magnet 53 is provided on the side opposite to the protruding side of the fitting claw 60a.
  • the fitting claw 60a has a shape that substantially follows the outer peripheral surface of the ball screw shaft 31 to be attached (see FIG. 5). For example, by pressing the first magnet holder 60 from the flat surface portion 31b1 side, Each pair of fitting claws 60a is deformed (elastically deformed) in a direction away from each other, and then restored toward a shape in close contact with the surface of the notch 31c.
  • the shape of the accommodating portion 60b is set according to the permanent magnet 53 to be accommodated.
  • a cylindrical housing portion 60 b is formed in the first magnet holder 60 in accordance with the columnar permanent magnet 53.
  • the accommodating portion 60b is opened only at one end in the axial direction thereof, and the permanent magnet 53 is inserted from the opening 60b1 side, and the second magnet holder 61 is cut out at the notch 31c so as to close the opening 60b1.
  • the permanent magnet 53 can be clamped by the first and second magnet holders 60 and 61 at a predetermined axial position. Therefore, by attaching the sensor target unit 59 having the above configuration to the notch 31c, the permanent magnet 53 is fixed at a predetermined axial position on the ball screw shaft 31 (see FIG. 1).
  • the material of the magnet holders 60 and 61 having the above configuration is basically arbitrary.
  • the magnet holders 60 and 61 are preferably made of a nonmagnetic material, and the elastic deformability of the fitting claw 60a is taken into account. It is good to use resin.
  • the permanent magnet 53 has a magnetization direction in a direction orthogonal to both end faces 53a and 53b (see FIG. 1). That is, it is in a state of being magnetized so that one end face 53a is an N pole and the other end face 53b is an S pole. Thereby, the magnetization direction of the permanent magnet 53 in the state attached to the ball screw shaft 31 is made to correspond with the linear motion direction of the ball screw shaft 31 (refer FIG. 1).
  • the position detection apparatus configured as described above, when the ball screw shaft 31 moves back and forth, the position of the permanent magnet 53 with respect to the magnetic sensor 54 changes, and accordingly, the magnetic field at the location where the magnetic sensor 54 is arranged also changes. Therefore, the change in the magnetic field (for example, the direction and strength of the magnetic flux density) is detected by the magnetic sensor 54, so that the position of the permanent magnet 53 in the stroke direction and the stroke of the operation unit 6 provided on one end side of the ball screw shaft 31. The direction position can be acquired.
  • the change in the magnetic field for example, the direction and strength of the magnetic flux density
  • the electric actuator 1 supports the ball screw nut 30 as the rotating portion of the motion conversion mechanism with the two bearings 13 and 14, and the two bearings 13 and 14 are supported by the ball screw mechanism.
  • 11 is configured to be attached to an equal-diameter cylindrical surface 37 having a constant inner diameter dimension provided on the inner periphery of a ball screw case 12 that accommodates 11.
  • an assembly error can be obtained as compared with the case where the bearings 13 and 14 are mounted across a plurality of cases. And so on.
  • the mounting surface common to the two bearings 13 and 14 is an equal-diameter cylindrical surface 37 having a constant inner diameter dimension, for example, two surfaces having different inner diameter dimensions through steps are mounted on the bearing surfaces 13 and 14, respectively.
  • the shape accuracy (processing accuracy) of the mounting surface can be easily increased. Therefore, the rotation centers of the bearings 13 and 14 are made to coincide with each other with high accuracy, and the rotation center of the ball screw nut 30 supported by the bearings 13 and 14 is relative to the center line of the ball screw shaft 31 as the linear motion portion. It is possible to prevent as much as possible a shift or tilt, or to suppress a shift or tilt as small as possible. As a result, the driving force transmitted from the driving motor 7 to the ball screw nut 30 can be efficiently transmitted to the ball screw shaft 31. Moreover, it becomes possible to control the electric actuator 1 with high accuracy by increasing the positional accuracy of the ball screw shaft 31.
  • the ball screw case 12 is configured such that the metal cylindrical member 38 is integrally provided, and the equal-diameter cylindrical surface 37 is provided on the inner periphery of the cylindrical member 38.
  • the cylindrical member 38 made of metal, it is possible to maintain the shape accuracy of the mounting surface (equal-diameter cylindrical surface 37) even when the bearings 13 and 14 are mounted.
  • the material can be made of resin with higher mass productivity. Therefore, it is suitable not only for positional accuracy but also for processing cost.
  • FIG. 8 shows a longitudinal sectional view of the electric actuator 101 according to the second embodiment of the present invention.
  • FIG. 9 is a partially exploded perspective view of the electric actuator 101 shown in FIG.
  • the electric actuator 101 according to the present embodiment has a configuration in which the speed reduction mechanism unit 8 is omitted.
  • the electric actuator 101 according to the present embodiment has a configuration in which the speed reduction mechanism unit 8 is omitted.
  • a coupling 62 as a connecting portion is provided, and the driving motor 7 is connected by this coupling 62.
  • the ball screw nut 30 are directly connected.
  • the coupling 62 has a flat surface 62a on the outer periphery, and is fitted and fixed to the inner peripheral surface 30c (see FIG. 8) on the other axial end side of the ball screw nut 30, for example, by fitting. This enables connection with the ball screw nut 30 and torque transmission.
  • the configuration other than the above is the same as that of the electric actuator 1 according to the first embodiment. That is, in this embodiment, the speed reduction mechanism case 10 according to the first embodiment is used as it is as a driving force transmission mechanism case for housing the coupling 62. Therefore, as shown in FIG. 9, the ring gear 48 constituting the planetary gear speed reduction mechanism 22 remains, but the members housed in the speed reduction mechanism case 10 are one of the coupling 62 and the output shaft 7 b of the drive motor 7. And only a part of the ball screw nut 30, there is no possibility of interference with the ring gear 48. Therefore, the speed reduction mechanism case 10 according to the first embodiment can be used as it is as a driving force transmission mechanism case. As described above, in the electric actuator 1 shown in FIG.
  • the rotation support structure of the ball screw nut 30 is the same as that of the first embodiment. Therefore, the rotation centers of the bearings 13 and 14 are matched with high accuracy and supported by these bearings 13 and 14. The situation where the rotation center of the ball screw nut 30 is displaced or inclined with respect to the center line of the ball screw shaft 31 as the linear motion portion can be prevented as much as possible, or the displacement and inclination can be minimized. . Therefore, it is possible to efficiently transmit the driving force transmitted from the driving motor 7 to the ball screw nut 30 to the ball screw shaft 31.
  • FIG. 10 shows a longitudinal sectional view of the electric actuator 201 according to the third embodiment of the present invention.
  • 11 is a partially exploded perspective view of the electric actuator 201 shown in FIG. 10
  • FIG. 12 is an exploded perspective view of a main part of the electric actuator 201 whose perspective direction is changed from that in FIG.
  • the electric actuator 201 according to the present embodiment has a different type of drive motor compared to the electric actuator 1 shown in FIG. 1, specifically, the first and second embodiments.
  • the drive motor 63 has a larger output than the drive motor 7 and the power supply structure of the drive motor 63 is changed.
  • the driving force transmission mechanism case 64 is similar to the speed reduction mechanism case 10 shown in FIG. 1.
  • the case main body 23, the screw case fitting portion 24, the motor fitting portion 17, And the flange portion 25 are integrally provided.
  • a pair of bus bars 65 for connecting the driving motor 63 to the power source is attached (built in) to the driving force transmission mechanism case 64.
  • one end portion 65a of each bus bar 65 is connected to a terminal 63a protruding in the axial direction from the driving motor 63 by, for example, close contact with caulking or the like, and the other end portion 65b is connected to the case. It is exposed to the outside from the main body 23 (flange portion 25) (see FIGS. 10 to 12).
  • the grommet 21 see FIG. 3
  • no hole is opened (closed) in the bottom of the motor cover 66.
  • the configuration other than the above is the same as that of the electric actuator 101 according to the second embodiment. That is, in this embodiment, the motion conversion mechanism unit 3 (ball screw mechanism 11 and ball screw case 12), the motion conversion mechanism support unit 5, the operation unit 6, and the drive motor 63 and the ball according to the second embodiment. A connecting portion (coupling 62) for connecting to the screw nut 30 is used as it is.
  • the electric actuator 101 shown in FIG. 8 and the electric actuator 201 shown in FIG. 10 only a part of the components (the speed reduction mechanism case 10 and the driving force transmission mechanism case 64) is mainly replaced. Parts can be composed of common parts.
  • the driving force transmission mechanism case 64 having the bus bar 65 and the structure without the speed reduction mechanism portion 8 are exemplified. It is also possible to configure an electric actuator having both 64 and the speed reduction mechanism 8.
  • the motion conversion mechanism 3 is not limited to the ball screw mechanism 11 and may be a sliding screw device.
  • the ball screw mechanism 11 is more preferable from the viewpoint of reducing the rotational torque and reducing the size of the drive motor 7.
  • the structure which used the deep groove ball bearing was illustrated as the bearings 13 and 14 which support the motion conversion mechanism part 3, it is not restricted to this, For example, you may use an angular ball bearing.
  • the bearings 13 and 14 are not limited to rolling bearings, and other types of bearings such as sliding bearings may be used.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transmission Devices (AREA)
  • Bearings For Parts Moving Linearly (AREA)

Abstract

La présente invention concerne un actionneur électrique (1) comprenant : un moteur (7) ; un convertisseur de mouvement (11) destiné à convertir le mouvement de rotation produit par l'entraînement du moteur (7) en mouvement linéaire ; et une enveloppe (12) destinée à loger le convertisseur de mouvement (11) à son intérieur. Le convertisseur de mouvement (11) comprend : une unité à mouvement linéaire (31) ; et une unité de rotation (30) disposée sur la circonférence externe de l'unité à mouvement linéaire (31). L'unité de rotation (30) est portée par deux paliers (13, 14) disposés séparément dans la direction de sa ligne centrale. Les deux paliers (13, 14) sont fixés à une face cylindrique isodiamétrique (37) présentant un diamètre interne constant et disposée sur la circonférence interne de l'enveloppe (12).
PCT/JP2017/032225 2016-09-15 2017-09-07 Actionneur électrique WO2018051873A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016180683A JP6752663B2 (ja) 2016-09-15 2016-09-15 電動アクチュエータ
JP2016-180683 2016-09-15

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WO2018051873A1 true WO2018051873A1 (fr) 2018-03-22

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI752694B (zh) * 2019-10-28 2022-01-11 美商施耐寶公司 雙減速齒輪系

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020148672A1 (en) * 2001-04-13 2002-10-17 Nsk Ltd. Electric power steering apparatus
JP2013096536A (ja) * 2011-11-04 2013-05-20 Ntn Corp 車両用懸架装置
JP2013234735A (ja) * 2012-05-10 2013-11-21 Nsk Ltd アクチュエータ装置
JP2015172436A (ja) * 2014-02-24 2015-10-01 Ntn株式会社 歯車およびこれを備えた電動アクチュエータ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020148672A1 (en) * 2001-04-13 2002-10-17 Nsk Ltd. Electric power steering apparatus
JP2013096536A (ja) * 2011-11-04 2013-05-20 Ntn Corp 車両用懸架装置
JP2013234735A (ja) * 2012-05-10 2013-11-21 Nsk Ltd アクチュエータ装置
JP2015172436A (ja) * 2014-02-24 2015-10-01 Ntn株式会社 歯車およびこれを備えた電動アクチュエータ

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI752694B (zh) * 2019-10-28 2022-01-11 美商施耐寶公司 雙減速齒輪系
US11565394B2 (en) 2019-10-28 2023-01-31 Snap-On Incorporated Double reduction gear train

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JP6752663B2 (ja) 2020-09-09

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