WO2024135483A1 - Actionneur - Google Patents

Actionneur Download PDF

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Publication number
WO2024135483A1
WO2024135483A1 PCT/JP2023/044566 JP2023044566W WO2024135483A1 WO 2024135483 A1 WO2024135483 A1 WO 2024135483A1 JP 2023044566 W JP2023044566 W JP 2023044566W WO 2024135483 A1 WO2024135483 A1 WO 2024135483A1
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WO
WIPO (PCT)
Prior art keywords
carrier
axial direction
nut
screw shaft
bearing
Prior art date
Application number
PCT/JP2023/044566
Other languages
English (en)
Japanese (ja)
Inventor
諒 瀬川
Original Assignee
日本精工株式会社
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 日本精工株式会社 filed Critical 日本精工株式会社
Priority to JP2024520984A priority Critical patent/JP7563654B1/ja
Publication of WO2024135483A1 publication Critical patent/WO2024135483A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
    • 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
    • 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
    • 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

  • This disclosure relates to actuators.
  • the actuator includes a motor and a ball screw device that converts rotational motion into linear motion.
  • the ball screw device has a nut, a screw shaft that passes through the nut, and a number of balls that are arranged between the nut and the screw shaft.
  • the actuator in the patent document below also has a rotating member that transmits the rotational motion of the motor to the screw shaft. The rotating member passes through one end of the screw shaft, and the rotating member and the screw shaft are connected. When the screw shaft rotates together with the rotating member, the nut moves in the axial direction.
  • the actuator may further include a planetary gear mechanism that decelerates the rotational motion.
  • the planetary gear mechanism includes an input shaft, a sun gear fixed to the input shaft, an internal gear fixed to the housing, multiple planetary gears that mesh with the sun gear and the internal gear, and a carrier that rotatably supports the planetary gears via a transmission shaft.
  • a planetary gear mechanism When using such a planetary gear mechanism, one end of the screw shaft passes through the carrier, connecting the screw shaft and the carrier.
  • a method can be considered in which a stepped surface is provided on the screw shaft that faces one side of the carrier, one side of the carrier is machined to be flat, and the stepped surface is brought into contact with one side of the carrier.
  • the area of the flattening process is the entire one side of the carrier, which requires a lot of effort and reduces the precision of the flattening (flatness).
  • the present disclosure has been made in consideration of the above, and aims to provide an actuator that can reduce the labor required for flat surface processing and improve the accuracy of flat surface processing.
  • an actuator includes a motor, a planetary gear mechanism having a carrier, and a ball screw device.
  • the ball screw device has a screw shaft, a nut, and a plurality of balls that are connected to the carrier.
  • the carrier has a carrier body, a boss portion, and a female spline hole.
  • the carrier body has a first surface facing one side of an axial direction parallel to the screw shaft, and a second surface facing the other side of the axial direction.
  • the boss portion protrudes from the center of the second surface to the other side of the axial direction.
  • the female spline hole penetrates the carrier body and the boss portion in the axial direction.
  • the screw shaft has a male spline portion that spline-fits with the female spline hole, and a screw shaft body that extends from the male spline portion to the other side of the axial direction and has an outer circumferential raceway surface on its outer circumferential surface.
  • the screw shaft body is formed with a larger diameter than the male spline portion.
  • a step surface facing one side in the axial direction is provided at the boundary between the screw shaft body and the male spline portion.
  • the boss portion has an end surface facing the other side in the axial direction and machined to be flat. The end surface abuts against the step surface.
  • the screw shaft from being connected to the carrier at an angle.
  • the area of flattening is limited to the end face of the boss. This reduces the effort required for flattening and improves the accuracy of flattening (planarity).
  • the inner circumferential surface of the nut is formed with a groove surface along which the balls roll.
  • the outer diameter of the boss portion is smaller than the inner diameter of the nut.
  • the amount of protrusion of the boss portion toward the other side in the axial direction is smaller than the length from one end face of the nut facing one side in the axial direction to the groove surface.
  • the boss portion can be placed inside the nut. This allows the actuator to be made smaller in size in the axial direction. Furthermore, even if the boss portion is placed inside the nut, the boss portion does not come into contact with the ball.
  • the outer peripheral surface of the boss portion is provided with a protrusion that protrudes radially outward.
  • the end face of the nut facing the other side in the axial direction is provided with a stopper that enters the path of the protrusion that rotates with the carrier and comes into contact with the protrusion.
  • the inner ring of the bearing is formed integrally with the carrier.
  • the inner ring of the bearing may be formed separately from the carrier.
  • the bearing is one of a four-point contact ball bearing, a double row ball bearing, and a double row angular contact ball bearing.
  • the axial center of the spline fit between the carrier and the screw shaft is shifted in the other axial direction by the boss.
  • the axial center of the spline fit is shifted in the other axial direction from the axial center of the bearing that supports the carrier. Therefore, when the radial load acting on the screw shaft is transmitted to the carrier, the carrier may tilt.
  • the bearing that supports the carrier is either a four-point contact ball bearing, a double row ball bearing, or a double row angular ball bearing, which has a large load capacity against moment loads. This prevents the carrier from tilting.
  • the center of the first surface is provided with a concave surface that is recessed toward the other side of the axial direction and has an opening for the female spline hole on its bottom surface.
  • the actuator disclosed herein reduces the labor required for flattening and improves the accuracy of flattening.
  • FIG. 1 is a cross-sectional view of a brake booster according to an embodiment taken along an axial direction in a state prior to actuation.
  • FIG. 2 is a cross-sectional view of the nut according to the embodiment cut in the axial direction.
  • FIG. 3 is an enlarged view of the vicinity of the carrier in the actuator of FIG.
  • FIG. 4 is a diagram showing a process for forming the crimped portion of the embodiment.
  • FIG. 5 is an enlarged view of the vicinity of the concave surface of the carrier in the actuator of the first modification.
  • FIG. 6 is an enlarged view of the vicinity of the concave surface of the carrier in the actuator of the second modification.
  • FIG. 7 is a diagram showing a state in which the nut is removed from the actuator of the third modified example.
  • FIG. 8 is a diagram showing a state in which the nut is removed from the actuator of the fourth modified example.
  • (Embodiment) 1 is a cross-sectional view of a brake booster according to an embodiment cut in the axial direction in a state before activation.
  • an actuator according to the present disclosure is applied to a brake booster of a brake system.
  • the actuator according to the present disclosure may be applied to other devices such as a brake caliper in addition to the brake booster shown in the embodiment.
  • the actuator 100 of the embodiment includes a housing 101, a motor (not shown), a planetary gear mechanism 1, a ball screw device 50, and a piston 80.
  • the direction parallel to the central axis O of the screw shaft 51 of the ball screw device 50 is referred to as the axial direction.
  • the direction in which the planetary gear mechanism 1 is disposed as viewed from the piston 80 is referred to as the first direction X1, and the opposite direction to the first direction X1 is referred to as the second direction X2.
  • the housing 101 is provided with a cylinder 102.
  • the cylinder 102 has a cylindrical portion 103 that is cylindrical about a central axis O, and a blocking wall 104 that blocks the opening of the cylindrical portion 103 in the second direction X2.
  • a piston 80 is inserted into the opening of the cylindrical portion 103 in the first direction X1, thereby blocking the internal space of the cylinder 102.
  • a liquid (not shown) is sealed in the internal space of the cylinder 102.
  • a through hole 104a is provided in the blocking wall 104.
  • the planetary gear mechanism 1 includes an input shaft 2, a sun gear 3, a ring gear 4, a number of planetary gears 5, a number of transmission shafts 6, a carrier 7, and a bearing 8.
  • the torque generated by the motor is transmitted to the input shaft 2.
  • the input shaft 2 is arranged coaxially with the central axis O.
  • the input shaft 2 is also arranged in the first direction X1 with respect to the screw shaft 51.
  • the input shaft 2 of the present disclosure may be configured as the output shaft of a motor (not shown).
  • the sun gear 3 is inserted through the input shaft 2 and is fixed to the input shaft 2 so that it cannot rotate.
  • the ring gear 4 is an internal gear that forms an annular shape around the input shaft 2.
  • the outer peripheral surface of the ring gear 4 is fitted into the housing 101.
  • the planetary gear 5 is disposed between the sun gear 3 and the ring gear 4, and meshes with both the sun gear 3 and the ring gear 4.
  • the planetary gear 5 is passed through by the transmission shaft 6.
  • the transmission shaft 6 also passes through the carrier 7 at a position eccentric radially outward from the center of the carrier 7.
  • the planetary gear 5 is supported by the carrier 7 so as to be freely rotatable about the transmission shaft 6.
  • the carrier 7 is a disk-shaped part centered on the central axis O.
  • the carrier 7 is supported by the housing 101 via the bearing 8 so as to be freely rotatable.
  • the side surface of the outer ring 8a of the bearing 8 in the first direction X1 abuts against the ring gear 4 via the spacer 9a.
  • the ring gear 4 and the outer ring 8a are sandwiched between a step surface 105 and a retaining ring 9b provided on the housing 101.
  • the carrier 7 is disposed between the input shaft 2 and the screw shaft 51.
  • a female spline hole 30 is formed in the carrier 7. This female spline hole 30 passes through the center of the carrier 7 in the axial direction.
  • the inner peripheral surface of the female spline hole 30 has internal teeth extending in the axial direction.
  • the ball screw device 50 includes a screw shaft 51, a nut 60, and a number of balls 70.
  • the screw shaft 51 includes a male spline portion 52 and a screw shaft body 53 extending from the male spline portion 52 in the second direction X2.
  • the male spline portion 52 has external teeth extending in the axial direction formed on its outer peripheral surface.
  • the male spline portion 52 is inserted into the female spline hole 30 of the carrier 7 and is spline-fitted.
  • the external teeth of the male spline portion 52 are inserted between the internal teeth of the female spline hole 30.
  • the external teeth of the male spline portion 52 and the internal teeth of the female spline hole 30 abut against each other in the circumferential direction. This spline fit connects the carrier 7 and the screw shaft 51 so that they cannot rotate relative to each other.
  • the outer peripheral surface of the screw shaft body 53 is provided with an outer peripheral raceway surface 54 extending in the spiral direction.
  • the screw shaft body 53 has a larger diameter than the male spline section 52. Therefore, a step surface 55 facing the first direction X1 is provided at the boundary between the male spline section 52 and the screw shaft body 53.
  • the step surface 55 is a plane perpendicular to the central axis O. The step surface 55 abuts against the carrier 7 from the second direction X2. Therefore, the screw shaft 51 is restricted from moving in the first direction X1.
  • Figure 2 is a cross-sectional view of the nut of the embodiment cut in the axial direction.
  • the nut 60 has a nut body 61, a plurality of inner circumferential raceway surfaces 62, and a plurality of S-shaped groove surfaces 63.
  • the nut body 61 is cylindrical with the center at the central axis O.
  • the inner diameter of the nut body 61 is L1.
  • the nut body 61 has a first end face 64 facing the first direction X1, and a second end face 65 facing the second direction X2.
  • the second end face 65 serves as a pressing surface that presses the piston 80 (see Figure 1) in the second direction X2.
  • the inner raceway surface 62 and the multiple S-shaped groove surfaces 63 are groove surfaces provided on the inner surface 61a of the nut body 61.
  • the inner raceway surface 62 faces the outer raceway surface 54 (see FIG. 1) of the screw shaft 51 and extends in the helical direction.
  • the inner raceway surface 62 extends one revolution (one lead) in the helical direction.
  • a raceway is formed between each inner raceway surface 62 and the outer raceway surface 54.
  • a multiple number of balls 70 are arranged in each raceway.
  • the S-shaped groove surface 63 is a groove surface formed on the inner surface 61a of the nut body 61 by forging.
  • the S-shaped groove surface 63 is connected to one end and the other end of the spiral direction of the inner raceway surface 62.
  • the ball 70 that moves from one end of the raceway to the other end is circulated to one end of the raceway by the S-shaped groove surface 63.
  • four inner raceway surfaces 62 and four S-shaped groove surfaces 63 are provided. Of the four inner raceway surfaces 62 and four S-shaped groove surfaces 63, those that are located furthest in the first direction X1 are referred to as the first inner raceway surface 62a and the first S-shaped groove surface 63a.
  • the distance from the first end face 64 of the nut 60 to the groove surface is L2.
  • the first S-shaped groove surface 63a is disposed closer to the first direction X1 than the first inner circumferential raceway surface 62a. Therefore, in this embodiment, the distance from the first end face 64 to the first S-shaped groove surface 63a is L2.
  • the nut 60 is provided with a rotation prevention portion that protrudes radially outward from the outer circumferential surface of the nut body 61. This rotation prevention portion is inserted into a guide groove that extends in the axial direction and is provided in the housing 101. As a result, the nut 60 is supported by the housing 101 so that it cannot rotate around the central axis O, but can move in the axial direction.
  • the piston 80 has a pressing portion 81 that is disk-shaped and centered on the central axis O, a cylindrical portion 82 that extends from the pressing portion 81 in the first direction X1, and a fitting portion 83 that fits into the outer peripheral surface of the nut 60.
  • the pressing portion 81 is a portion that presses the liquid in the cylinder 102 in the second direction X2.
  • the pressing portion 81 is disposed inside the cylinder 102 and faces the closing wall 104 of the cylinder 102.
  • the outer diameters of the cylindrical portion 82 and the fitting portion 83 are slightly smaller than the inner diameter of the cylinder 102. Therefore, a minute gap (not shown) is provided between the outer peripheral surface of the piston 80 and the inner peripheral surface of the cylinder 102. Therefore, the piston 80 is supported so as to be movable in the axial direction while sliding on the inner peripheral surface of the cylinder 102.
  • the inner diameter of the cylindrical portion 82 is smaller than the inner diameter of the fitting portion 83. Therefore, an abutment surface 84 facing the first direction X1 is provided at the boundary between the inner peripheral surface of the cylindrical portion 82 and the inner peripheral surface of the fitting portion 83. The abutment surface 84 abuts against the second end face 65 of the nut 60. Therefore, when the nut 60 moves in the second direction X2, the abutment surface 84 is pressed, and the piston 80 moves in the second direction X2.
  • the hydraulic pressure of the liquid in the cylinder 102 acts on the pressing portion 81.
  • the piston 80 is constantly pressed in the first direction X1. Therefore, the abutment surface 84 and the second end surface 65 are constantly in abutment.
  • Two seal members 108 are provided between the piston 80 and the cylinder 102. This prevents the liquid in the cylinder 102 from leaking in the first direction X1 through the tiny gap between the piston 80 and the cylinder 102.
  • the actuator 100 when the motor is driven, the input shaft 2 and the sun gear 3 rotate around the central axis O.
  • the planetary gear 5 rotates around the central axis O while rotating around the transmission shaft 6.
  • This causes the carrier 7 and the screw shaft 51 to rotate around the central axis O.
  • the rotation speed of the screw shaft 51 is slower than the rotation speed of the input shaft 2.
  • the second end surface 65 presses the abutment surface 84, and the piston 80 moves in the second direction X2.
  • This increases the hydraulic pressure in the cylinder 102.
  • the piston 80 also moves in the first direction X1.
  • the hydraulic pressure in the cylinder 102 decreases.
  • FIG. 3 is an enlarged view of the vicinity of the carrier of the actuator of FIG. 1.
  • the carrier 7 has a carrier body 10, a boss portion 20, and a female spline hole 30.
  • the carrier body 10 is disk-shaped with the central axis O as the center.
  • the carrier body 10 has a first surface 11 facing the first direction X1, a second surface 12 facing the second direction, and an outer peripheral surface 13.
  • the first surface 11 has a concave surface 40 at its center, which is recessed in the second direction X2.
  • the concave surface 40 has a bottom surface 41 that is circular about the central axis O, and an inner peripheral surface 42 that is cylindrical about the central axis O.
  • the internal space 43 of the concave surface 40 is a cylindrical space.
  • the inner diameter of the inner peripheral surface 42 is larger than the outer diameter of the male spline portion 52 (the inner diameter of the female spline hole 30).
  • the outer periphery of the carrier 7 constitutes the inner ring of the bearing 8. For this reason, an outer periphery rolling groove 13a is formed on the outer periphery surface 13 of the carrier 7.
  • the bearing 8 is disposed on the radial outside of the carrier 7.
  • the bearing 8 comprises an outer ring 8a that fits into the housing 101, and a number of balls 8b that are disposed between the outer ring 8a and the carrier 7.
  • An inner circumferential rolling groove 8c is formed on the inner circumferential surface of the outer ring 8a.
  • the outer circumferential rolling groove 13a and the inner circumferential rolling groove 8c are Gothic arc shaped.
  • the balls 8b contact the outer circumferential rolling groove 13a and the inner circumferential rolling groove 8c at two points each. Therefore, the outer ring 8a and the outer periphery of the carrier 7 form a four-point contact ball bearing. For these reasons, the bearing 8 has a large load capacity for the moment load input to the carrier 7.
  • the boss portion 20 protrudes in the second direction X2 from the center of the second surface 12 of the carrier body 10.
  • the boss portion 20 is cylindrical with the center at the central axis O.
  • the boss portion 20 has an end face 21 facing the second direction X2.
  • This end face 21 is processed to be flat. Therefore, the end face 21 has high flatness and is a plane perpendicular to the central axis O.
  • the step surface 55 of the screw shaft 51 abuts against this end face 21.
  • the flat processing method may be a method in which the end face 21 (carrier 7) is moved in a direction perpendicular to the central axis O while cutting the end face 21 from the second direction X2, but the present disclosure is not limited to this method.
  • the outer diameter L3 of the boss portion 20 is smaller than the inner diameter L1 of the nut 60 (see FIG. 2). This allows the boss portion 20 to be positioned inside the nut 60 (see the boss portion 20 shown by the dashed line in FIG. 2). In other words, when the actuator 100 is started, the initial position of the nut 60 (piston 80) can be closer to the first direction X1. As a result, the axial length of the cylinder 102 can be shortened.
  • the outer diameter L3 of the boss portion 20 is larger than the inner diameter of the inner circumferential surface 42 of the concave surface 40.
  • the amount of protrusion L4 of the boss portion 20 in the second direction X2 is smaller than the length L2 from the first end face 64 of the nut 60 to the groove surface (first S-shaped groove surface 63a).
  • the female spline hole 30 penetrates the carrier body 10 and the boss portion 20 about the central axis O. Therefore, the bottom surface 41 of the concave surface 40 and the end surface 21 of the boss portion 20 are provided with a first opening 31 and a second opening 32, which are the openings of the female spline hole 30.
  • the end of the screw shaft 51 in the first direction X1 enters the internal space 43 of the concave surface 40 from the first opening 31. Furthermore, the portion of the end of the screw shaft 51 in the first direction X1 that is disposed in the internal space 43 constitutes a crimped portion 56. This crimped portion 56 is larger than the inner diameter of the female spline hole 30 and abuts against the bottom surface 41 from the first direction X1. This prevents the screw shaft 51 from slipping out of the female spline hole 30.
  • Figure 4 is a diagram showing the process of forming the crimped portion of the embodiment.
  • the male spline portion 52 before the crimped portion 56 is formed has an axial length longer than the female spline hole 30. Therefore, the end portion 52a of the male spline portion 52 in the first direction X1 enters the internal space 43 from the first opening 31.
  • the jig 200 is used to form the crimped portion 56.
  • a recess 201 is formed on the tip surface of the jig 200.
  • the recess 201 is a recess formed in a circular shape when viewed from the axial direction.
  • the inner peripheral surface of the recess 201 is a tapered surface 202 that expands in diameter as it approaches the tip surface of the jig 200.
  • the crimping operation is performed by inserting the jig 200 into the internal space 43 of the concave surface 40. Then, the end 52a of the male spline portion 52 in the first direction X1 is inserted into the recess 201.
  • the tapered surface 202 of the recess 201 is brought into contact with the external teeth of the male spline portion 52.
  • the jig 200 is pressed in the second direction X2. As a result, the external teeth of the male spline portion 52 are crushed (crimped), and the crimped portion 56 is formed.
  • the area where flattening is performed is the end face 21 of the boss portion 20, which is narrower than the second surface 12 of the carrier 7. Therefore, the area (area) where flattening is performed is small, and the labor required for flattening is reduced. In addition, the accuracy of flattening is improved. Therefore, the screw shaft 51 is connected perpendicular to the end face 21. As a result, the screw shaft 51 is prevented from being connected at an angle to the carrier 7.
  • the crimped portion 56 of the screw shaft 51 is housed in the internal space 43 of the concave surface 40. This prevents the crimped portion 56 from coming into contact with the input shaft 2 or the sun gear 3.
  • the axial center M1 of the female spline hole 30 is disposed in the second direction X2 further than the axial center M2 of the carrier 7. For this reason, when a radial load acts on the screw shaft 51, there is a possibility that the carrier 7 will tilt. If the carrier 7 tilts, the transmission shaft 6 will also tilt, and the rotation of the planetary gear 5 will not be smooth.
  • the bearing 8 of this embodiment constitutes a four-point contact ball bearing, and has a large load capacity for the moment load input to the carrier 7. Therefore, the carrier 7 is less likely to tilt, and smooth rotation of the planetary gear 5 is ensured.
  • the actuator 100 of the embodiment includes a motor, a planetary gear mechanism 1 having a carrier 7, and a ball screw device 50.
  • the ball screw device 50 has a screw shaft 51 connected to the carrier 7, a nut 60, and a plurality of balls 70.
  • the carrier 7 has a carrier body 10, a boss portion 20, and a female spline hole 30.
  • the carrier body 10 has a first surface 11 facing one side of the axial direction (first direction X1) parallel to the screw shaft 51, and a second surface 12 facing the other side of the axial direction (second direction X2).
  • the boss portion 20 protrudes from the center of the second surface 12 to the other side of the axial direction.
  • the female spline hole 30 penetrates the carrier body 10 and the boss portion 20 in the axial direction.
  • the screw shaft 51 has a male spline section 52 that is spline-fitted into the female spline hole 30, and a screw shaft body 53 that extends from the male spline section 52 in the other axial direction and has an outer circumferential raceway surface 54 on its outer circumferential surface.
  • the screw shaft body 53 is formed with a larger diameter than the male spline section 52.
  • a step surface 55 facing one axial direction is provided at the boundary between the screw shaft body 53 and the male spline section 52.
  • the boss section 20 has an end face 21 that faces the other axial direction and is machined to be flat. The end face 21 abuts against the step surface 55.
  • the area (range) of the flattening process can be reduced, reducing the labor required for the flattening process.
  • the accuracy of the flattening process is improved.
  • a groove surface on which the balls 70 roll is formed on the inner peripheral surface 61a of the nut 60.
  • the outer diameter L3 of the boss portion 20 is smaller than the inner diameter L1 of the nut 60.
  • the amount of protrusion L4 of the boss portion 20 toward the other side in the axial direction is smaller than the length L2 from one end face (first end face 64) of the nut 60 facing one side in the axial direction to the groove surface.
  • the actuator 100 (cylinder 102) can be made smaller in the axial direction.
  • the boss portion 20 enters the inner periphery of the nut 60, the boss portion 20 does not come into contact with the ball 70.
  • the inner ring of the bearing 8 is formed integrally with the carrier 7.
  • the inner ring of the bearing 8 is not required, which reduces the number of parts.
  • a concave surface 40 is provided in the center of the first surface 11, which is recessed in the other axial direction and has an opening (first opening 31) of the female spline hole 30 on its bottom surface 41.
  • the crimping portion 56 is prevented from coming into contact with the input shaft 2 and the sun gear 3.
  • the bearing 8 in the embodiment is a four-point contact ball bearing, but the present disclosure may be a double row ball bearing or a double row angular ball bearing. This is because a double row ball bearing or a double row angular ball bearing has a large load capacity for the moment load input to the carrier 7. Furthermore, the present disclosure is not limited to bearings with a large load capacity for the moment load, and may be a deep groove ball bearing. Furthermore, the inner ring of the bearing 8 in the embodiment is formed integrally with the carrier 7, but the present disclosure may be an inner ring separate from the carrier 7.
  • the tightening portion 56 prevents the screw shaft 51 from coming out of the female spline hole 30, but in the present disclosure, a retaining ring may be used instead of the tightening portion 56.
  • a clamping margin may be provided on the internal teeth of the female spline hole 30 or the external teeth of the male spline portion 52 so that the male spline portion 52 is less likely to come out of the female spline hole 30. Examples of clamping margins for the internal or external teeth include providing a fleshy portion (plastic deformation portion) in the gap between the teeth, or providing a fleshy portion (plastic deformation portion) that protrudes radially from the teeth, but the present disclosure is not limited to these.
  • the boss portion 20 can be disposed inside the nut 60, but the boss portion 20 does not have to be disposed inside the nut 60. Furthermore, if the boss portion 20 is not disposed inside the nut 60, the outer diameter L3 of the boss portion 20 may be larger than the inner diameter L1 of the nut 60.
  • the concave surface 40 is formed on the carrier 7, but the present disclosure may also be directed to a carrier 7 in which the concave surface 40 is not formed. Note that, if the concave surface 40 is not formed, the swage portion 56 and the retaining ring for preventing the screw shaft 51 from coming loose are provided so as to hook onto (contact) the first surface 11 of the carrier 7.
  • the input shaft 2A of the actuator 100A of the first modification passes through the sun gear 3.
  • the tip 2a (end in the second direction X2) of the input shaft 2A protrudes in the second direction X2 from the end face 3a of the sun gear 3 in the second direction X2.
  • the tip 2a of the input shaft 2A also protrudes in the second direction X2 beyond the first surface 11.
  • the tip 2a of the input shaft 2A is disposed in the internal space 43 of the concave surface 40.
  • the outer diameter of the input shaft 2A is smaller than the inner diameter of the inner peripheral surface 42 of the concave surface 40. Therefore, the tip 2a of the input shaft 2A rotates without coming into contact with the inner peripheral surface 42.
  • the tip 2a of the input shaft 2A is disposed in the internal space 43, so the distance L5 between the end face 3a of the sun gear 3 and the first surface 11 of the carrier 7 is reduced.
  • the actuator 100A can be made smaller in the axial direction. Note that in modification 1, the tip 2a of the input shaft 2A is disposed in the internal space 43, but if a part such as a retaining ring that prevents the sun gear 3 from coming loose is attached to the tip 2a of the input shaft 2A, the tip 2a of the input shaft 2A and the part such as the retaining ring may be disposed together in the internal space 43, or only the part such as the retaining ring may be disposed in the internal space 43.
  • Figure 6 is an enlarged view of the vicinity of the concave surface of the carrier in the actuator of variant 2.
  • the sun gear 3B of the actuator 100B of variant 2 has a greater length in the tooth width direction (axial direction) than the planetary gear 5. With this sun gear 3B, even if the assembly positions of the input shaft 2B and the sun gear 3B are misaligned in the axial direction, the sun gear 3B will come into contact with the entire area of the teeth of the planetary gear 5 in the tooth width direction (axial direction).
  • the tip 2a of the input shaft 2B and the end 3b of the sun gear 3B in the second direction X2 protrude in the second direction X2 beyond the first surface 11.
  • the tip 2a of the input shaft 2B and the end 3b of the sun gear 3B in the second direction X2 are disposed in the internal space 43.
  • the outer diameter of the sun gear 3B is smaller than the inner diameter of the inner circumferential surface 42 of the concave surface 40. Therefore, the end 3b of the sun gear 3B in the second direction X2 rotates without contacting the inner circumferential surface 42.
  • the sun gear 3B can be disposed in the second direction X2 more than when the concave surface 40 is not formed, and the actuator 100b can be made smaller in the axial direction.
  • boss portion 20 in the embodiment is formed in a cylindrical shape, in the present disclosure it may be a polygonal prism such as a triangular prism or a quadrangular prism.
  • boss portion 20 may be modified to have other functions. Below, modified examples 3 and 4 in which the boss portion is modified are described.
  • FIG. 7 shows the actuator of modified example 3 with the nut removed.
  • the outer peripheral surface of the boss portion 20C of the actuator 100C of modified example 3 has a protrusion 23 that protrudes radially outward.
  • the protrusion 23 is also continuous with the second surface 12 of the carrier body 10. When the motor is driven, the protrusion 23 rotates together with the carrier 7. In other words, the protrusion 23 moves in the circumferential direction around the central axis O.
  • the protrusion 23 faces the first end face 64 of the nut 60C.
  • a stopper 67 that protrudes in the first direction X1 is provided on the first end face 64 of the nut 60C.
  • the stopper 67 enters the trajectory of the protrusion 23 that moves circumferentially around the central axis O, and comes into contact with the protrusion 23. This stops the rotation of the carrier 7 and the screw shaft 51, and restricts the nut 60 from moving further in the first direction X1.
  • FIG. 8 is a diagram showing the state in which the nut has been removed from the actuator of Variation 4.
  • the actuator 100D of Variation 4 differs from Variation 3 in that an annular wall portion (part of the nut body 61) 68 is provided on the outer periphery of the stopper 67.
  • the stopper 67 is continuous with the inner periphery of this annular wall portion 68.
  • the initial position of the nut 60 when the actuator 100D is started is determined.
  • the stopper 67 is continuous with the annular wall portion 68, improving rigidity.
  • a flange may be provided on the outer periphery of the annular wall portion 68 to further improve rigidity.
  • the S-shaped groove surface 63 is given as the circulation part that circulates the balls 70, but in the present disclosure, a top, a deflector (end deflector, middle deflector), a tube, etc. may also be used.
  • a motor a planetary gear mechanism having a carrier; a ball screw device including a screw shaft connected to the carrier, a nut, and a plurality of balls; Equipped with The carrier is A carrier body having a first surface facing one side of an axial direction parallel to the screw axis and a second surface facing the other side of the axial direction; a boss portion protruding from a central portion of the second surface in the other axial direction; a female spline hole penetrating the carrier body and the boss portion in the axial direction; having The screw shaft is a male spline portion that is spline-fitted into the female spline hole; a threaded shaft body extending from the male spline portion in the other axial direction and having an outer circumferential surface provided with an outer circumferential raceway; having The screw shaft body is formed to have a larger diameter than the male spline portion, A step surface facing one side in the axial direction is provided
  • a groove surface along which the balls roll is formed on the inner peripheral surface of the nut, The outer diameter of the boss portion is smaller than the inner diameter of the nut, The actuator according to (1), wherein an amount of protrusion of the boss portion in the other axial direction is smaller than a length from one end face of the nut facing one side in the axial direction to the groove surface.
  • a protrusion protruding radially outward is provided on an outer circumferential surface of the boss portion,
  • the planetary gear mechanism has a bearing that rotatably supports the carrier, The actuator according to any one of (1) to (3), wherein an inner ring of the bearing is integrally formed with the carrier.
  • the planetary gear mechanism has a bearing that rotatably supports the carrier, The actuator according to any one of (1) to (3), wherein an inner ring of the bearing is formed separately from the carrier.
  • the planetary gear mechanism has a bearing that rotatably supports the carrier, The actuator according to any one of (1) to (5), wherein the bearing is any one of a four-point contact ball bearing, a double row ball bearing, and a double row angular contact ball bearing.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Transmission Devices (AREA)

Abstract

Cet actionneur comprend : un moteur ; un mécanisme d'engrenage planétaire ayant un support ; et un dispositif de vis à billes ayant un arbre à vis qui est couplé au support, à un écrou et à une pluralité de billes. Le support comprend : un corps de support ayant une première surface faisant face à un côté dans la direction axiale, ainsi qu'une seconde surface faisant face à l'autre côté dans la direction axiale ; une partie bosselée faisant saillie vers l'autre côté dans la direction axiale à partir d'une partie centrale de la seconde surface ; et un trou cannelé femelle traversant le corps du support et la partie bosselée dans la direction axiale. L'arbre à vis comprend une partie cannelée mâle, ainsi qu'un corps d'arbre à vis comprenant un plan d'orbite circonférentielle externe sur la surface circonférentielle externe de celui-ci. Le corps d'arbre à vis est formé avec un diamètre supérieur à celui de la partie cannelée mâle La limite entre le corps d'arbre à vis et la partie cannelée mâle est pourvue d'une surface étagée faisant face au premier côté dans la direction axiale. La partie bosselée présente une surface d'extrémité qui fait face à l'autre côté dans la direction axiale et a subi un aplatissement. La surface d'extrémité vient en butée sur la surface étagée.
PCT/JP2023/044566 2022-12-20 2023-12-13 Actionneur WO2024135483A1 (fr)

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JP2022-203377 2022-12-20

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140274548A1 (en) * 2013-03-14 2014-09-18 Black & Decker Inc. Clutch for power tool
JP2022187272A (ja) * 2021-06-07 2022-12-19 日本精工株式会社 電動アクチュエータ
JP2023131479A (ja) * 2022-03-09 2023-09-22 株式会社アイシン 電動シリンダの回転支持構造

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6422302B2 (ja) 2014-10-27 2018-11-14 リンナイ株式会社 直線駆動装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140274548A1 (en) * 2013-03-14 2014-09-18 Black & Decker Inc. Clutch for power tool
JP2022187272A (ja) * 2021-06-07 2022-12-19 日本精工株式会社 電動アクチュエータ
JP2023131479A (ja) * 2022-03-09 2023-09-22 株式会社アイシン 電動シリンダの回転支持構造

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