WO2024253085A1 - Dispositif de charge rotative - Google Patents

Dispositif de charge rotative Download PDF

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Publication number
WO2024253085A1
WO2024253085A1 PCT/JP2024/020353 JP2024020353W WO2024253085A1 WO 2024253085 A1 WO2024253085 A1 WO 2024253085A1 JP 2024020353 W JP2024020353 W JP 2024020353W WO 2024253085 A1 WO2024253085 A1 WO 2024253085A1
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WO
WIPO (PCT)
Prior art keywords
rotation
rotating shaft
cam groove
load device
groove
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
PCT/JP2024/020353
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English (en)
Japanese (ja)
Inventor
光司 佐藤
隆英 齋藤
慎太朗 石川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NTN Corp
Original Assignee
NTN Corp
NTN Toyo Bearing Co Ltd
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
Priority claimed from JP2023092904A external-priority patent/JP2024175261A/ja
Priority claimed from JP2023092901A external-priority patent/JP2024175260A/ja
Priority claimed from JP2023092907A external-priority patent/JP2024175264A/ja
Application filed by NTN Corp, NTN Toyo Bearing Co Ltd filed Critical NTN Corp
Publication of WO2024253085A1 publication Critical patent/WO2024253085A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear

Definitions

  • This invention relates to a rotational load device that generates a rotational reaction force.
  • Patent Document 1 A known rotational load device used to apply a steering reaction force to a steering wheel is described in Patent Document 1.
  • the rotational load device in Patent Document 1 has a cylindrical drum that rotates integrally with the steering shaft that is connected to the steering wheel, a band-shaped member that is in frictional contact with the outer periphery of the drum, and a coil spring that adjusts the tension of the band-shaped member, and is configured to generate a rotational reaction force due to frictional resistance between the drum and the band-shaped member when the driver rotates the steering wheel.
  • the inventors of this application believed that if a rotation load device could generate a force to return the steering wheel to the neutral position, it would be possible to improve the steering feel felt by the driver when turning the steering wheel.
  • the problem that the first and second inventions aim to solve is to provide a rotational load device that is capable of generating a rotational reaction force using only mechanical parts and is suitable for applying a steering reaction force to a steering wheel.
  • the axial movement of the sliding cylinder elastically deforms the elastic member, and the elastic force transmitted from the elastic member to the rotating shaft via the sliding cylinder and the cam pin generates a rotational reaction force of a magnitude corresponding to the rotation angle of the rotating shaft.
  • a rotational reaction force of a magnitude corresponding to the rotation angle of the rotating shaft is generated, it is suitable for applications that impart a steering reaction force to a steering wheel.
  • the slide cylinder further includes a ball that is held in a ball holding hole formed radially through the slide cylinder and that rolls and contacts the rolling groove.
  • the outer ring is prevented from rotating by the housing, and the balls held in the ball retaining holes of the sliding cylinder are in rolling contact with the rolling grooves that extend axially around the inner circumference of the outer ring, making it possible to prevent the sliding cylinder from rotating relative to the housing while keeping frictional resistance when the sliding cylinder moves in the axial direction extremely small.
  • This allows the sliding cylinder to move smoothly in the axial direction, and a stable amount of rotational reaction force can be generated.
  • the sliding cylinder is guided so that it can move axially at three or more positions spaced apart in the circumferential direction, so the center position of the sliding cylinder is stable and the operation of the sliding cylinder can be made particularly stable.
  • the sliding cylinder is guided so that it can move axially at two or more positions spaced apart in the axial direction, preventing the sliding cylinder from tilting and making the operation of the sliding cylinder particularly stable.
  • the cam groove is formed in a V-shape such that the axial position of the cam groove changes to one side in the axial direction from the circumferential center of the cam groove toward either one circumferential direction or the other circumferential direction, 5.
  • the rotational load device according to any one of configurations 1 to 4, wherein the elastic member is provided so as to bias the slide cylinder to the one side in the axial direction.
  • a stopper groove extending in a circumferential direction within an angular range of less than 360° is provided on one of the rotating shaft and the housing, and a stopper protrusion positioned within the stopper groove is provided on the other of the rotating shaft and the housing;
  • This configuration is particularly suitable for use in steer-by-wire steering devices, as the rotation angle of the rotating shaft is detected by the rotation angle sensor.
  • a reduction gear is provided to reduce the speed of rotation input from the outside and transmit the reduced speed to the rotating shaft.
  • the cam groove is provided at three or more locations at intervals in the circumferential direction of the slide cylinder,
  • the rotation load device according to any one of configurations 1 to 7, wherein the cam pins are also provided at three or more locations circumferentially spaced apart on the outer periphery of the rotating shaft.
  • a reducer is provided that reduces the speed of the rotation input from the outside and transmits it to the rotating shaft, so the rotation angle of the rotating shaft is smaller than the rotation angle input from the outside, and the circumferential width of the cam groove can be set smaller.
  • three or more cam grooves can be provided in the circumferential direction, which stabilizes the center position of the sliding cylinder and makes it possible to make the operation of the sliding cylinder particularly stable.
  • the speed reducer is configured such that a rotation center of a rotation input part to which rotation is input from an outside and a rotation center of a rotation output part which reduces the rotation of the rotation input part and outputs the reduced rotation are positioned on the same line, the rotation input portion has an input side convex portion which rotates and moves integrally with the rotation input portion about the rotation center of the rotation input portion when a rotation is input to the rotation input portion from the outside, and the rotation output portion has an output side convex portion which rotates and moves integrally with the rotation output portion about the rotation center of the rotation output portion at the same axial position as the input side convex portion when a rotation is input to the rotation input portion from the outside,
  • the rotational range of the rotational input part is restricted by utilizing the difference in rotational speed between the rotational input part and the rotational output part of the reducer, making it possible to set a large rotational range for the rotational input part (for example, an angle range of 360° or more).
  • the reducer is a planetary gear reducer having a sun gear arranged so that its center of rotation is on the same line as the center of rotation of the rotating shaft, a ring gear with internal teeth fixed to the inner circumference of the housing, a plurality of planetary gears arranged at intervals in the circumferential direction between the ring gear and the sun gear and meshing simultaneously with the ring gear and the sun gear, and a planetary carrier that supports the plurality of planetary gears so that they can rotate around the center of each planetary gear and revolve around the sun gear, wherein the sun gear constitutes a rotational input section to which rotation is input from the outside, and the planetary carrier constitutes a rotational output section that reduces the rotation of the rotational input section and outputs it.
  • a rotational load device as described in configuration 9 or 10.
  • the reducer can be compactly arranged in line with the center of rotation of the rotating shaft, and the configuration of the reducer is simple and low cost.
  • a second aspect of the present invention provides a rotational load device having the following configuration.
  • a rotating shaft having a cam groove on its outer periphery, the axial position of which changes along a circumferential direction, and being rotatably supported; an outer ring formed in a cylindrical shape surrounding an outer periphery of the rotating shaft and having an axial groove extending in the axial direction on an inner periphery; a steel ball inserted between the rotating shaft and the outer ring so as to be in rolling contact with both the cam groove and the axial groove; a cylindrical cage that holds the steel balls in retaining holes formed radially through the cage and is disposed between the outer periphery of the rotating shaft and the inner periphery of the outer ring so as to be movable in the axial direction; an elastic member that biases the retainer in the axial direction,
  • a rotational load device that applies a rotational reaction force to the rotating shaft by an elastic force transmitted from the elastic member
  • the cam groove is formed in a V-shape such that the axial position of the cam groove changes to one side in the axial direction from the circumferential center of the cam groove toward either one circumferential direction or the other circumferential direction, 13.
  • the rotational load device configured as described above is suitable for applications in which a steering reaction force is applied to a steering wheel.
  • the steel balls are provided at a plurality of different circumferential positions,
  • the cam groove is provided in a plurality of grooves corresponding to the plurality of steel balls,
  • the retainer is guided by multiple steel balls arranged at different circumferential positions, so the center position of the retainer is stable, and the operation of the retainer can be made stable.
  • the bearing further includes a housing that accommodates the outer ring while preventing it from rotating.
  • a stopper groove extending in a circumferential direction within an angular range of less than 360° is provided in the housing, and a stopper protrusion positioned within the stopper groove is provided on the rotating shaft;
  • This configuration is particularly suitable for use in steer-by-wire steering devices, as the rotation angle of the rotating shaft is detected by the rotation angle sensor.
  • the wedge angle between the tangent direction at the point of contact between the inner surface of the cam groove and the steel ball and the extension direction of the axial groove is 50° or more and 90° or less when viewed in a cross section perpendicular to the extension direction of the cam groove, so the steel ball is less likely to get caught in the wedge angle.
  • the inclination angle of the cam groove relative to the circumferential direction is set to less than 25°, so the axial length of the portion of the outer periphery of the rotating shaft where the cam groove is formed can be reduced, making it possible to make the axial length of the rotating load device compact.
  • the inclination angle of the cam groove relative to the circumferential direction is set to less than 25°, there is a large difference in orientation between the direction in which the steel ball is pushed by the biasing force of the elastic member (axial direction) and the extension direction of the cam groove. Therefore, when the steel ball is pushed axially by the biasing force of the elastic member, the problem of the steel ball getting caught in the wedge angle formed by the cam groove and the axial groove when viewed in a cross section perpendicular to the extension direction of the cam groove is easily apparent.
  • the wedge angle to a value between 50° and 90°, it is possible to effectively prevent the steel ball from getting caught in the wedge angle.
  • the cam groove has an inner surface that rises from the bottom of the cam groove to the other side in the axial direction when viewed in a cross section perpendicular to the extension direction of the cam groove, and because this inner surface is linear in cross section, the rising angle of the inner surface is the wedge angle itself. Therefore, the size of the wedge angle is less susceptible to the effects of misalignment of the relative positions of the rotating shaft and outer ring, or dimensional errors in the axial groove and cam groove, and the size of the wedge angle is stable.
  • the cam groove has an inner surface that is linear in cross section and rises from the bottom of the cam groove to the other side in the axial direction when viewed in a cross section perpendicular to the extension direction of the cam groove.
  • the cam pin on the outer periphery of the rotating shaft slides in the cam groove of the sliding cylinder and moves in rotation together with the rotating shaft.
  • the sliding cylinder is prevented from rotating relative to the housing, and the cam groove of the sliding cylinder is formed so that the axial position changes along the circumferential direction. Therefore, when the cam pin slides in the cam groove and moves in rotation together with the rotating shaft, the sliding cylinder moves in the axial direction in response to the rotational movement of the cam pin.
  • the axial movement of the sliding cylinder elastically deforms the elastic member, and the elastic force transmitted from the elastic member to the rotating shaft via the sliding cylinder and the cam pin generates a rotational reaction force of a magnitude corresponding to the rotation angle of the rotating shaft.
  • a rotational reaction force of a magnitude corresponding to the rotation angle of the rotating shaft is generated, it is suitable for applications that impart a steering reaction force to a steering wheel.
  • the cam groove on the outer circumference of the rotating shaft moves circumferentially together with the rotating shaft.
  • the steel balls that roll into the cam groove are restricted from moving circumferentially relative to the outer ring by engaging with the axial groove on the inner circumference of the outer ring, so when the cam groove moves circumferentially, the steel balls that roll into the cam groove are pressed against the inner surface of the cam groove and move axially.
  • FIG. 1 is a schematic diagram showing a steer-by-wire steering device using a rotation load device according to a first embodiment of the first invention
  • 2 is a cross-sectional view of the rotary load device of FIG. 1
  • 3 is a cross-sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.
  • FIG. 3 is a top view of the rotary load device of FIG. 2 with the housing body removed.
  • FIG. 7 is a diagram showing a state in which the rotation shaft shown in FIG. 6 is rotated and the slide cylinder is moved in the axial direction.
  • FIG. 3 is a diagram showing a rotation load device according to a second embodiment of the first invention, corresponding to FIG. 2.
  • Cross-sectional view taken along line XX in FIG. 10 is a cross-sectional view taken along line XI-XI of FIG.
  • FIG. 9 is a top view of the rotation load device of FIG. 8 with the housing body removed.
  • FIG. 13 is a diagram showing a state in which the input shaft shown in FIG. 12 is rotated and the slide cylinder moves in the axial direction;
  • FIG. 3 is a diagram showing a rotation load device according to an embodiment of the second invention, corresponding to FIG. 2.
  • 15 is a cross-sectional view taken along line XV-XV of FIG.
  • FIG. 16 is a cross-sectional view taken along line XVI-XVI of FIG.
  • FIG. 15 is an exploded perspective view showing the outer ring, the rotating shaft, and the cage of FIG.
  • FIG. 15 is a top view of the rotary load device of FIG. 14 with the housing and the outer ring removed.
  • FIG. 19 is a diagram showing a state in which the rotating shaft shown in FIG. 18 is rotated and the cage is moved in the axial direction; 20 is a cross-sectional view taken along line XX-XX of FIG.
  • FIG. 19 is a diagram showing a state in which the rotating shaft shown in FIG. 18 is rotated to a position between a neutral position and a limit position of a rotatable range.
  • FIG. 22 is a cross-sectional view taken along line XXII-XXII of FIG.
  • FIG. 23 is a diagram showing an example of a cam groove having a triangular cross section, corresponding to FIG. 22.
  • FIG. 23 is a diagram showing an example of a cam groove having a trapezoidal cross section corresponding to FIG. 22 .
  • FIG. 23 is a diagram showing an example of a cam groove having a rectangular cross section, corresponding to FIG. 22.
  • FIG. 1 shows a steering device using a rotational load device 1 according to a first embodiment of the first invention.
  • This steering device is a steer-by-wire type vehicle steering device that converts the amount of operation of a steering wheel 2 by a driver into an electrical signal and controls a steering actuator 3 based on the electrical signal to change the direction of a pair of steered wheels 4 on the left and right.
  • This steering device has a steering wheel 2 that is rotated by the driver, a steering shaft 5 connected to the steering wheel 2, a rotation load device 1 that is mechanically connected to the steering wheel 2 via the steering shaft 5, a steering actuator 3 that is mechanically separated from the steering wheel 2, and a control unit 6.
  • the steering shaft 5 connects the steering shaft 5 to the rotation load device 1 so that when the driver rotates the steering wheel 2, the rotation of the steering wheel 2 is input to the rotation load device 1 via the steering shaft 5.
  • the rotation load device 1 When a rotation is input, the rotation load device 1 generates a rotational reaction force corresponding to the rotation, thereby applying a steering reaction force to the steering wheel 2.
  • the steering actuator 3 has a steering shaft 7, a steering shaft housing 8, a steering motor 9 that moves the steering shaft 7 in the left-right direction of the vehicle, and a steering sensor 10 that detects the position of the steering shaft 7.
  • the steering shaft 7 is supported by the steering shaft housing 8 so that it can move in the left-right direction of the vehicle.
  • the steering shaft housing 8 contains the center of the steering shaft 7 so that both the left and right ends of the steering shaft 7 protrude from the steering shaft housing 8.
  • the steering motor 9 and steering sensor 10 are attached to the steering shaft housing 8. Between the steering motor 9 and the steering shaft 7, a motion conversion mechanism (not shown) is installed that converts the rotation output by the steering motor 9 into linear motion of the steering shaft 7.
  • the left and right ends of the steering shaft 7 are connected to a pair of left and right steered wheels 4 via tie rods 11, so that when the steering shaft 7 moves in the axial direction, the orientation of the pair of left and right steered wheels 4 changes in conjunction with this.
  • the control unit 6 operates the steering motor 9 in response to the amount of operation of the steering wheel 2 detected by a rotation angle sensor 12 built into the rotation load device 1 and the vehicle's driving conditions (vehicle speed, etc.) detected by an external sensor 13, and controls the change in the direction of the pair of steered wheels 4 on the left and right.
  • the rotation load device 1 has a housing 14, a rotating shaft 15 to which the rotation of the steering wheel 2 (see FIG. 1) is input, a sliding tube 16 that fits axially on the outer periphery of the rotating shaft 15 so as to be able to slide axially, and an elastic member 17 that biases the sliding tube 16 in the axial direction.
  • the housing 14 has a housing body 14A and a housing lid 14B.
  • the housing body 14A is a bottomed cylindrical member having a tubular portion 18 arranged to surround the radial outside of the rotating shaft 15, and an end plate portion 19 formed at one end (the left end in the figure) of the tubular portion 18 so as to face the axial end of the rotating shaft 15.
  • the housing lid 14B is removably attached to the other end (the right end in the figure) of the tubular portion 18 with a bolt 20.
  • the housing cover 14B is formed in the shape of an annular plate through which the rotating shaft 15 passes, and a rolling bearing 21 that rotatably supports the rotating shaft 15 is mounted on its inner periphery.
  • a rolling bearing 22 that rotatably supports the rotating shaft 15 is also mounted in the housing main body 14A.
  • the rotating shaft 15 is rotatably supported relative to the housing 14 with its axial movement relative to the housing 14 restricted by the rolling bearings 21 and 22.
  • the end of the rotating shaft 15 protruding from the housing 14 is connected to the steering shaft 5 ( Figure 1).
  • An outer ring 23 is fitted and attached to the inner circumference of the tubular portion 18 of the housing body 14A.
  • the outer ring 23 is a tubular member with both ends open, and is made of steel.
  • the housing body 14A is made of a light metal (such as an aluminum alloy).
  • the outer ring 23 is sandwiched in the axial direction between a step 24 formed on the inner circumference of the housing body 14A and the housing lid 14B, thereby restricting its axial movement relative to the housing 14.
  • a notch 25 (see FIG.
  • the outer ring 23 is prevented from rotating relative to the housing 14 by engaging the notch 25 of the outer ring 23 with the axial protrusion 26 of the housing lid 14B.
  • a common key member may be fitted into a key groove on the outer periphery of the outer ring 23 and a key groove on the inner periphery of the housing body 14A, or the outer periphery of the outer ring 23 may be spline-fitted with the inner periphery of the housing body 14A.
  • a flat portion may be provided on the outer periphery of the outer ring 23, and a protrusion that engages with the flat portion may be provided on the inner periphery of the housing body 14A.
  • the inner circumference of the outer ring 23 is provided with three rolling grooves 28 at equal intervals in the circumferential direction, in which the balls 27 roll.
  • Each rolling groove 28 is formed to extend linearly in the axial direction around the inner circumference of the outer ring 23.
  • the slide tube 16 is also provided with three ball retaining holes 29 at equal intervals in the circumferential direction for retaining the balls 27.
  • the ball retaining holes 29 are formed to penetrate the slide tube 16 in the radial direction, and the balls 27 retained in the ball retaining holes 29 are in rolling contact with the inner surface of the rolling groove 28 on the inner circumference of the outer ring 23 and the cylindrical surface on the outer circumference of the rotating shaft 15. Due to the engagement between the balls 27 and the rolling grooves 28, the slide tube 16 is prevented from rotating relative to the housing 14 while being movable axially relative to the housing 14.
  • the balls 27 have a diameter larger than the radial thickness of the sliding tube 16 so that a portion of the balls 27 protrudes radially outward from the ball retaining hole 29 when the balls 27 are in contact with the cylindrical surface of the outer periphery of the rotating shaft 15. Steel balls are used for the balls 27.
  • the ball retaining hole 29 is a circular hole that runs along the outer periphery of the balls 27.
  • the sliding tube 16 may be made of steel, or may be made of an oil-impregnated sintered alloy or synthetic resin. By making the sliding tube 16 out of an oil-impregnated sintered alloy or synthetic resin, it is possible to effectively reduce the axial sliding resistance of the sliding tube 16.
  • the balls 27 and ball retaining holes 29 are provided at two locations at the same circumferential position of the slide cylinder 16, spaced apart in the axial direction.
  • the two balls 27 engage with a common rolling groove 28.
  • the slide cylinder 16 is formed with a cam groove 30 whose axial position changes along the circumferential direction.
  • the cam groove 30 can be formed to extend along the inner circumference of the slide cylinder 16 without penetrating the slide cylinder 16 in the radial direction, but here it is formed as a slit that penetrates the slide cylinder 16 in the radial direction.
  • a cam pin 31 is provided on the outer periphery of the rotating shaft 15.
  • the cam pin 31 is assembled in such a way that one end is press-fitted into a pin hole 32 formed on the outer periphery of the rotating shaft 15 and the other end protrudes from the pin hole 32.
  • the part of the cam pin 31 protruding from the pin hole 32 is inserted into the cam groove 30 of the slide cylinder 16.
  • the V-shaped cam groove 30 is shown as having a shape in which a straight line with a constant angle of inclination with respect to the circumferential direction connects the position corresponding to the bottom of the V with the positions corresponding to both ends of the V, but it is also possible to use a shape in which a plurality of straight lines with a stepwise changing angle of inclination with respect to the circumferential direction connect the position corresponding to the bottom of the V with the positions corresponding to both ends of the V, or a shape in which a curve with a smoothly changing angle of inclination with respect to the circumferential direction connects the position corresponding to the bottom of the V with the positions corresponding to both ends of the V.
  • the elastic member 17 is incorporated into a cylindrical space formed between the inner circumference of the outer ring 23 and the outer circumference of the rotating shaft 15.
  • the elastic member 17 may be a compression spring such as a compression coil spring, a wave spring, or a disc spring.
  • the end plate 19 of the housing body 14A is provided with a rotation angle sensor 12 that detects the rotation angle of the rotating shaft 15.
  • the rotation angle sensor 12 can be made up of a permanent magnet 35 that is attached to the rotating shaft 15 and is fixed so as to rotate together with the rotating shaft 15, and a magnetic detection unit 36 that is provided facing the permanent magnet 35.
  • the magnetic detection unit 36 is fixed to the end plate 19 with a bolt 37.
  • this rotary load device 1 is less susceptible to wear compared to rotary load devices configured to generate a rotational reaction force by frictional resistance between a drum and a strip-shaped member, such as those in Patent Publication No. 4853412 (Patent Document 1), and can ensure stable operation over a long period of time.
  • the outer ring 23 shown in FIG. 2 is prevented from rotating by the housing 14, and the balls 27 held in the ball holding holes 29 of the sliding tube 16 are in rolling contact with the rolling grooves 28 that extend axially around the inner circumference of the outer ring 23.
  • This makes it possible to prevent the sliding tube 16 from rotating relative to the housing 14 while keeping the frictional resistance when the sliding tube 16 moves in the axial direction extremely small. This allows the sliding tube 16 to move smoothly in the axial direction, and a stable amount of rotational reaction force can be generated.
  • the sliding cylinder 16 is guided so as to be movable in the axial direction at three positions spaced apart in the circumferential direction, so that the center position of the sliding cylinder 16 is stable and the operation of the sliding cylinder 16 is particularly stable.
  • the rotation load device 1 When the steering wheel 2 is returned to the neutral position, the rotation load device 1 generates a force (a force assisting the rotation operation of the steering wheel 2) that returns the steering wheel 2 to the neutral position, which makes it possible to improve the steering feeling of the steering wheel 2 by the driver.
  • this rotation load device 1 is provided with a rotation angle sensor 12 that detects the rotation angle of the rotating shaft 15, making it particularly suitable for use in a steer-by-wire type steering device as shown in FIG. 1.
  • the rotation load device 1 has a housing 14, an input shaft 50 to which the rotation of the steering wheel 2 (see FIG. 1) is input, a reducer 51 that reduces the rotation input to the input shaft 50 and transmits it to the rotating shaft 15, a sliding tube 16 that fits axially on the outer periphery of the rotating shaft 15 so as to be slidable in the axial direction, and an elastic member 17 that biases the sliding tube 16 in the axial direction.
  • the input shaft 50 and the rotating shaft 15 are arranged side by side so that the rotation center of the input shaft 50 and the rotation center of the rotating shaft 15 are aligned on the same straight line.
  • the housing cover 14B is formed in the shape of an annular plate through which the input shaft 50 passes, and a rolling bearing 21 that rotatably supports the input shaft 50 is mounted on its inner periphery.
  • a rolling bearing 22 that rotatably supports the rotating shaft 15 is mounted in the housing main body 14A.
  • the rotating shaft 15 is rotatably supported relative to the housing 14 by the rolling bearings 21, 22, with its axial movement relative to the housing 14 restricted.
  • the end of the input shaft 50 protruding from the housing 14 is connected to the steering shaft 5 ( Figure 1).
  • the cam grooves 30 are provided at three locations on the slide cylinder 16 at equal intervals in the circumferential direction.
  • the cam pins 31 are also provided at three locations on the outer periphery of the rotating shaft 15 at equal intervals in the circumferential direction.
  • the reducer 51 is a planetary gear reducer having a sun gear 52, an internally toothed ring gear 53 fixed to the inner circumference of the housing 14, a number of planetary gears 54 spaced apart in the circumferential direction between the ring gear 53 and the sun gear 52, and a planetary carrier 55 that supports the planetary gears 54 so that they can rotate around the center of each planetary gear 54 and revolve around the sun gear 52.
  • the sun gear 52 is provided integrally on the axial end of the input shaft 50.
  • the sun gear 52 is an external gear arranged so that its center of rotation is on the same straight line as the center of rotation of the rotating shaft 15.
  • the planetary gear 54 is simultaneously meshed with the ring gear 53 and the sun gear 52.
  • the planetary carrier 55 has a plurality of carrier pins 56 that support each planetary gear 54 rotatably, and a carrier body 57 that maintains the circumferential spacing of the plurality of carrier pins 56.
  • the carrier body 57 is formed integrally on the axial end of the rotating shaft 15.
  • the ring gear 53 and outer ring 23 are axially sandwiched between a step 24 formed on the inner circumference of the housing body 14A and the housing lid 14B, restricting axial movement relative to the housing 14.
  • the ring gear 53 has a notch 58 (see FIG. 11) on its axial end face on the housing lid 14B side, and an axial protrusion 26 formed on the housing lid 14B engages with the notch 58, preventing it from rotating relative to the housing 14.
  • a notch 25 (see FIG. 10) is formed on the axial end face of the outer ring 23 on the ring gear 53 side, and an axial protrusion 59 formed on the ring gear 53 engages with the notch 25, preventing the outer ring 23 from rotating relative to the housing 14.
  • the ring gear 53 is prevented from rotating relative to the housing 14 by engaging the notch 58 of the ring gear 53 with the axial protrusion 26 of the housing cover 14B.
  • a common key member may be fitted into a key groove on the outer periphery of the ring gear 53 and a key groove on the inner periphery of the housing body 14A, or the outer periphery of the ring gear 53 may be spline-fitted with the inner periphery of the housing body 14A, or a flat portion may be provided on the outer periphery of the ring gear 53, and a protrusion that engages with the flat portion may be provided on the inner periphery of the housing body 14A.
  • the sun gear 52 constitutes the rotation input section to which rotation is input from the outside (steering wheel 2 shown in Figure 1)
  • the planetary carrier 55 constitutes the rotation output section that decelerates and outputs the rotation of the rotation input section.
  • the center of rotation of the rotation input section (sun gear 52) to which rotation is input from the outside and the center of rotation of the rotation output section (planetary carrier 55) that decelerates and outputs the rotation of the rotation input section are located on the same straight line.
  • the rotation input part (sun gear 52) of the reducer 51 has an input side convex part 60 that rotates and moves integrally with the rotation input part (sun gear 52) around the rotation center of the rotation input part (sun gear 52) when rotation is input to the rotation input part (sun gear 52).
  • the rotation output part (planet carrier 55) of the reducer 51 has an output side convex part 61 that rotates and moves integrally with the rotation output part (planet carrier 55) around the rotation center of the rotation output part (planet carrier 55) when rotation is input to the rotation input part (sun gear 52) from the outside.
  • the output side convex part 61 is provided at the same axial position as the input side convex part 60 (a position having a portion that overlaps with the input side convex part 60 when viewed from the radial direction).
  • the output side protrusion 61 is configured by fixing a key member separate from the rotating shaft 15 to the inner diameter of the shaft end of the rotating shaft 15. It is also possible to use an output side protrusion 61 that is seamlessly formed integrally with the inner diameter of the shaft end of the rotating shaft 15.
  • the input side convex portion 60 and the output side convex portion 61 shown in FIG. 10 constitute a rotation stopper that restricts the rotatable range of the rotation input portion (sun gear 52) by the input side convex portion 60 catching up with and abutting the output side convex portion 61 when rotation is input from the outside to the rotation input portion (sun gear 52).
  • the rotatable range of the rotation input portion (sun gear 52) is set to an angle range of 360° or more.
  • the input side convex portion 60 and the output side convex portion 61 are configured so that when the rotating shaft 15 shown in FIG. 9 rotates, the input side convex portion 60 and the output side convex portion 61 shown in FIG. 10 abut against each other before the cam pin 31 abuts against the circumferential end of the cam groove 30.
  • this rotation load device 1 since this rotation load device 1 has a reducer 51 that reduces the speed of the rotation input to the input shaft 50 and transmits it to the rotating shaft 15, the rotation angle of the rotating shaft 15 is smaller than the rotation angle input to the input shaft 50. Therefore, as shown in FIG. 12, the inclination angle of the cam groove 30 can be made large, making it possible to make the cam pin 31 slide smoothly within the cam groove 30. In addition, it is possible to reduce the axial length of the cam groove 30 and make the device more compact.
  • this rotary load device 1 uses the difference in rotational speed between the rotary input part (sun gear 52) and the rotary output part (planet carrier 55) of the speed reducer 51 to regulate the rotatable range of the rotary input part (sun gear 52), making it possible to set a large rotatable range of the rotary input part (sun gear 52) (to an angle range of 360° or more).
  • this rotary load device 1 has a rotary stopper formed by the input side protrusion 60 and the output side protrusion 61 provided on the reducer 51, making it possible to miniaturize the device.
  • this rotating load device 1 employs a planetary gear reducer as the reducer 51
  • the reducer 51 can be compactly arranged on the same straight line as the center of rotation of the rotating shaft 15, and the configuration of the reducer 51 is simple and low cost. Other effects are the same as those of the first embodiment.
  • a planetary gear reducer is used as the reducer 51 configured so that the center of rotation of the rotation input part, which receives rotation from the outside, and the center of rotation of the rotation output part, which reduces the rotation of the rotation input part and outputs it, are positioned on the same straight line.
  • an eccentric reducer such as a roller reducer, ball reducer, or cycloid reducer.
  • an elastic member 17 is described as being pressed and compressed in the axial direction by the axial movement of the sliding tube 16 when the rotating shaft 15 rotates.
  • an elastic member 17 that is pulled and stretched in the axial direction by the axial movement of the sliding tube 16 when the rotating shaft 15 rotates, and to configure the elastic member 17 to generate a rotational reaction force by the elastic force transmitted from the elastic member 17 to the rotating shaft 15 via the sliding tube 16 and the cam pin 31.
  • FIG. 14 shows a rotational load device 1 according to an embodiment of the second invention.
  • parts corresponding to those in the embodiment of the first invention are given the same reference numerals and their explanations are omitted.
  • parts given the same reference numerals basically have the same configuration.
  • the rotation load device 1 has a housing 14, a rotating shaft 15 to which the rotation of the steering wheel 2 (see FIG. 1) is input, a cylindrical outer ring 23 that surrounds the outer periphery of the rotating shaft 15, steel balls 40 incorporated between the rotating shaft 15 and the outer ring 23, a retainer 41 that holds the steel balls 40, and an elastic member 42 that biases the retainer 41 in the axial direction.
  • the outer ring 23 is accommodated in the housing 14.
  • two steel balls 40 are provided at different circumferential positions.
  • the circumferential positions of each steel ball 40 are at equally spaced circumferential positions (at circumferential positions equally spaced at 180° intervals in FIG. 16).
  • Two axial grooves 43 are formed on the inner circumference of the outer ring 23 corresponding to the two steel balls 40, and two cam grooves 44 are also formed on the outer circumference of the rotating shaft 15 corresponding to the two steel balls 40.
  • the cam grooves 44 are grooves whose axial positions change along the circumferential direction.
  • the retainer 41 is a cylindrical member that is axially movable between the outer periphery of the rotating shaft 15 and the inner periphery of the outer ring 23.
  • the retainer 41 is provided with retaining holes 45 that accommodate and hold each steel ball 40.
  • the retaining holes 45 are circular holes that run along the outer periphery of the steel ball 40.
  • the retaining holes 45 are formed to penetrate the retainer 41 in the radial direction.
  • the steel ball 40 has a diameter larger than the radial thickness of the retainer 41 (the radial length of the retaining hole 45) so that it rolls and comes into contact with both the axial groove 43 on the inner periphery of the outer ring 23 and the cam groove 44 on the outer periphery of the rotating shaft 15.
  • the steel ball 40, the axial groove 43, and the cam groove 44 constitute a motion conversion mechanism that converts the rotation of the rotating shaft 15 into the axial movement of the retainer 41.
  • the axial groove 43 on the inner circumference of the outer ring 23 is formed in a cross-sectional arc shape that follows the outer circumference of the steel ball 40.
  • the two axial grooves 43 are provided at circumferential positions that correspond to the respective circumferential positions of the two steel balls 40 (in FIG. 16, they are circumferential positions equally spaced 180° apart around the inner circumference of the outer ring 23).
  • the retainer 41 is prevented from rotating relative to the outer ring 23 by the engagement between the steel balls 40 and the axial groove 43, while being movable axially relative to the outer ring 23.
  • the axial groove 43 extends straight in the axial direction around the inner circumference of the outer ring 23.
  • the two cam grooves 44 are provided at circumferential positions that correspond to the circumferential positions of the two steel balls 40. That is, as shown in FIG. 18, the two cam grooves 44 have the same shape, and are provided so that they are circumferentially offset by 180° to correspond to the circumferential positions of the two steel balls 40.
  • the two steel balls 40 are positioned at positions offset in the axial direction, and the two cam grooves 44 are also provided at positions offset in the axial direction so as to correspond to the axial positions of the two steel balls 40.
  • the cam groove 44 is formed in a cross-sectional arc shape that follows the outer periphery of the steel ball 40.
  • Each cam groove 44 is formed in a V-shape such that the axial position of the cam groove 44 changes to one axial side (left side in the figure) whether moving in one axial direction or the other axial direction from the circumferential center of the cam groove 44 (the position corresponding to the bottom of the V).
  • the elastic member 42 is incorporated so as to urge the retainer 41 to the other axial side (right side in the figure) by pressing against the end face of the retainer 41 on one axial side (left side in the figure).
  • the elastic member 42 is arranged so as to be pressed against the retainer 41 and compressed when the rotating shaft 15 rotates, as shown in FIG. 19.
  • the V-shaped cam groove 44 is shown as having a shape in which the position corresponding to the bottom of the V and the positions corresponding to both ends of the V are connected by a straight line with a constant inclination angle with respect to the circumferential direction (i.e., a shape in which the ends of two partial spiral grooves with opposite leads are connected to each other), but a shape in which the position corresponding to the bottom of the V and the positions corresponding to both ends of the V are connected by multiple straight lines with a stepwise changing inclination angle with respect to the circumferential direction may also be used, or a shape in which the position corresponding to the bottom of the V and the positions corresponding to both ends of the V are connected by a curve with a smoothly changing inclination angle with respect to the circumferential direction may also be used.
  • the inclination angle with respect to the circumferential direction of the portion of the cam groove 44 that extends at an incline in the axial direction with respect to the circumferential direction is set to a value less than 25°.
  • the portion of cam groove 44 that extends at an incline in the axial direction with respect to the circumferential direction portion other than the portion corresponding to the bottom of the V-shape of cam groove 44
  • the cross-sectional shape of cam groove 44 is arc-shaped, and the wedge angle ⁇ is set to 50° or more by setting the arc radius to a value 110% or more of the radius of steel ball 40.
  • the elastic member 42 is incorporated into a cylindrical space formed between the inner circumference of the outer ring 23 and the outer circumference of the rotating shaft 15.
  • the elastic member 42 may be a compression spring such as a compression coil spring, a wave spring, or a disc spring.
  • the housing cover 14B is provided with a stopper groove 33 extending circumferentially over an angular range of less than 360°, and the outer periphery of the rotating shaft 15 is provided with a stopper protrusion 34 located within the stopper groove 33.
  • the stopper protrusion 34 and the stopper groove 33 form a rotation stopper that restricts the rotatable range of the rotating shaft 15 by the stopper protrusion 34 abutting against the circumferential end of the stopper groove 33 (the circumferential end of the stopper groove 33 receiving the stopper protrusion 34).
  • the circumferential length of the stopper groove 33 is set so that when the rotating shaft 15 shown in Figure 14 rotates, the stopper protrusion 34 shown in Figure 15 abuts against the circumferential end of the stopper groove 33 before the steel ball 40 abuts against the circumferential end of the cam groove 44.
  • the rotational load device 1 is capable of generating a rotational reaction force using only mechanical parts.
  • the rotational load device 1 can suppress frictional resistance to a small value and generate a rotational reaction force of a stable magnitude.
  • a rotational reaction force of a magnitude corresponding to the rotation angle of the rotating shaft 15 is generated, it is suitable for applications in which a steering reaction force is applied to the steering wheel 2.
  • this rotational load device 1 whether the rotating shaft 15 shown in FIG. 18 is rotated circumferentially from the neutral position (the position where the steel ball 40 is in the circumferential center of the cam groove 44) to one side or the other side, a rotational reaction force in a direction returning the rotating shaft 15 to the neutral position is generated by the circumferential component of the force with which the steel ball 40 presses axially against the inner surface of the cam groove 44. Therefore, when this rotational load device 1 is used with a steering wheel 2 (see FIG. 1), the steering feeling when returning the steering wheel 2 to the neutral position becomes lighter, making it possible to improve the steering feeling of the steering wheel 2. In this way, the rotational load device 1 configured as described above is suitable for applications in which a steering reaction force is applied to the steering wheel 2.
  • this rotary load device 1 is less prone to wear compared to the rotary load device 1 in Patent Publication No. 4853412 (Patent Document 1) that is configured to generate a rotational reaction force by frictional resistance between a drum and a strip-shaped member, and can ensure stable operation over a long period of time.
  • the cam groove 44 of the rotation load device 1 is formed in a V-shape such that the axial position of the cam groove 44 changes to one side in the axial direction (left side in the figure) whether moving from the circumferential center of the cam groove 44 to one side in the axial direction or the other side in the circumferential direction, and the elastic member 42 is provided to bias the retainer 41 to the other side in the axial direction (right side in the figure). Therefore, whether the rotating shaft 15 is rotated in one circumferential direction or the other circumferential direction, a rotation reaction force in the opposite direction to the rotation direction can be generated. Therefore, when the steering wheel 2 shown in FIG.
  • the rotation load device 1 When the steering wheel 2 is returned to the neutral position, the rotation load device 1 generates a force (force assisting the rotation operation of the steering wheel 2) that returns the steering wheel 2 to the neutral position, which makes it possible to improve the steering feeling of the steering wheel 2 by the driver.
  • this rotation load device 1 is provided with a rotation angle sensor 12 that detects the rotation angle of the rotating shaft 15, making it particularly suitable for use in a steer-by-wire type steering device such as that shown in FIG. 1.
  • the steel ball 40 is first pushed in the axial direction by the biasing force of the elastic member 42, but since the direction in which the steel ball 40 is pushed (axial direction) differs from the extension direction of the cam groove 44, as shown in FIG. 22, when viewed in a cross section perpendicular to the extension direction of the cam groove 44, the steel ball 40 may get caught in the wedge angle ⁇ formed by the cam groove 44 and the axial groove 43, which may hinder the rotation of the rotating shaft 15. This problem becomes more noticeable when the wedge angle ⁇ shown in FIG. 22 is small (for example, when the arc radius of the cam groove 44 shown in FIG. 22 is set to about 103% of the arc radius of the steel ball 40. In this case, the wedge angle ⁇ shown in FIG. 22 is less than 30°).
  • the inclination angle of the cam groove 44 in the circumferential direction of this rotational load device 1 is set to less than 25°, so that the axial length of the portion of the outer periphery of the rotating shaft 15 where the cam groove 44 is formed can be reduced, making it possible to make the axial length of the rotational load device 1 compact.
  • the cam groove 44 has an arc-shaped cross-sectional shape as shown in FIG. 22 when viewed in a cross section perpendicular to the extension direction of the cam groove 44.
  • All of the cam grooves 44 in Figures 22 to 25 have an inner surface 46 that is linear in cross section and rises from the bottom of the cam groove 44 to one side in the axial direction (the left side in the figures), and an inner surface 47 that is linear in cross section and rises from the bottom of the cam groove 44 to the other side in the axial direction (the right side in the figures).
  • the inner surface 47 on the other side in the axial direction of the cam groove 44 (the right side in the figures) is formed in a linear cross section that rises at an angle of 50° or more and less than 90°
  • the inner surface 47 on the other side in the axial direction of the cam groove 44 (the right side in the figures) is formed in a linear cross section that rises at an angle of 90°.
  • the cam groove 44 when viewed in a cross section perpendicular to the extension direction of the cam groove 44, the cam groove 44 has an inner side surface 47 that rises from the bottom of the cam groove 44 to the other side in the axial direction (the right side in the figure), and when the inner side surface 47 is configured to have a straight cross section, the rise angle of the inner side surface 47 becomes the wedge angle ⁇ shown in Figure 22 (the angle between the tangent direction at the point of contact between the inner surface of the cam groove 44 and the steel ball 40 and the extension direction of the axial groove 43).
  • the magnitude of the wedge angle ⁇ is less susceptible to the effects of misalignment of the relative positions of the rotating shaft 15 and the outer ring 23, or dimensional errors of the axial groove 43 and the cam groove 44, and the magnitude of the wedge angle ⁇ is stable.
  • an elastic member 42 is described as being pressed and compressed in the axial direction by the axial movement of the retainer 41 when the rotating shaft 15 rotates.
  • an elastic member 42 that is pulled and stretched in the axial direction by the axial movement of the retainer 41 when the rotating shaft 15 rotates, and to configure the elastic member 42 so that a rotational reaction force is generated by the elastic force transmitted from the elastic member 42 to the inner surface of the cam groove 44 via the retainer 41 and the steel ball 40.
  • the rotational load device 1 is used in a steer-by-wire vehicle steering device in which a pair of steered wheels 4 on the left and right sides of a vehicle are the steering objects, but this rotational load device 1 can also be used in, for example, a steer-by-wire ship steering device in which a rudder (such as an outboard motor) mounted at the stern of a ship is the steering object, and can also be applied to steer-by-wire steering devices for construction machinery, agricultural machinery, all-terrain vehicles, utility vehicles, and the like. Furthermore, it can also be used in other devices that require a rotational load, not just steering devices.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)

Abstract

L'invention concerne un dispositif de charge rotative comprenant un tube coulissant (16) qui est positionné autour du périmètre externe d'un arbre rotatif (15) de manière à pouvoir coulisser dans la direction axiale et un élément élastique (17) qui sollicite le tube coulissant (16) dans la direction axiale, une rainure de came (30), dont la position axiale change le long de la direction circonférentielle, étant formée dans le tube coulissant (16), et une broche de came (31), qui coulisse à l'intérieur de la rainure de came (30) lorsque l'arbre rotatif (15) tourne, étant disposée dans la périphérie externe de l'arbre rotatif (15).
PCT/JP2024/020353 2023-06-06 2024-06-04 Dispositif de charge rotative Pending WO2024253085A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2023-092904 2023-06-06
JP2023092904A JP2024175261A (ja) 2023-06-06 2023-06-06 回転負荷装置
JP2023092901A JP2024175260A (ja) 2023-06-06 2023-06-06 回転負荷装置
JP2023092907A JP2024175264A (ja) 2023-06-06 2023-06-06 回転負荷装置
JP2023-092907 2023-06-06
JP2023-092901 2023-06-06

Publications (1)

Publication Number Publication Date
WO2024253085A1 true WO2024253085A1 (fr) 2024-12-12

Family

ID=93796048

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2024/020353 Pending WO2024253085A1 (fr) 2023-06-06 2024-06-04 Dispositif de charge rotative

Country Status (1)

Country Link
WO (1) WO2024253085A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02114982A (ja) * 1988-10-25 1990-04-27 Taito Corp ゲーム機械用のステアリング装置
US5829745A (en) * 1995-03-28 1998-11-03 Home Arcade Systems, Inc. Video game control unit with self-centering steering wheel
JP2007106245A (ja) * 2005-10-13 2007-04-26 Toyota Motor Corp ステアリング操作装置
JP2009018666A (ja) * 2007-07-11 2009-01-29 Toyota Motor Corp 操舵反力付加装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02114982A (ja) * 1988-10-25 1990-04-27 Taito Corp ゲーム機械用のステアリング装置
US5829745A (en) * 1995-03-28 1998-11-03 Home Arcade Systems, Inc. Video game control unit with self-centering steering wheel
JP2007106245A (ja) * 2005-10-13 2007-04-26 Toyota Motor Corp ステアリング操作装置
JP2009018666A (ja) * 2007-07-11 2009-01-29 Toyota Motor Corp 操舵反力付加装置

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