WO2021019670A1 - Electric power steering device - Google Patents

Electric power steering device Download PDF

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Publication number
WO2021019670A1
WO2021019670A1 PCT/JP2019/029775 JP2019029775W WO2021019670A1 WO 2021019670 A1 WO2021019670 A1 WO 2021019670A1 JP 2019029775 W JP2019029775 W JP 2019029775W WO 2021019670 A1 WO2021019670 A1 WO 2021019670A1
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WO
WIPO (PCT)
Prior art keywords
electric power
steering device
power steering
rack shaft
gear
Prior art date
Application number
PCT/JP2019/029775
Other languages
French (fr)
Japanese (ja)
Inventor
美千広 亀田
保宏 堀内
Original Assignee
日鍛バルブ株式会社
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 日鍛バルブ株式会社 filed Critical 日鍛バルブ株式会社
Priority to JP2021536505A priority Critical patent/JPWO2021019670A1/ja
Priority to PCT/JP2019/029775 priority patent/WO2021019670A1/en
Publication of WO2021019670A1 publication Critical patent/WO2021019670A1/en

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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
    • 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
    • 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
    • F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/02—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
    • F16H3/08—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts
    • F16H3/083—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts with radially acting and axially controlled clutching members, e.g. sliding keys

Definitions

  • an electric power steering device that assists the driver in steering operation by converting the rotational motion of the electric motor into a linear motion of the rack axis by a belt transmission mechanism and a ball screw mechanism. Is disclosed.
  • the electric power steering device that employs a belt transmission mechanism rotates the electric motor via a belt installed between the main pulley that is rotated by the electric motor and the driven pulley that is integrated with the ball nut on the ball screw mechanism side. The torque is transmitted to the ball nut.
  • the present invention provides an electric power steering device in which a rotation transmission mechanism can be easily assembled to a drive conversion mechanism in the device.
  • a rotation transmission mechanism that transmits the rotation of the electric motor to rotate the nut mechanism, and a rotation transmission mechanism that converts the rotational movement of the nut mechanism into a reciprocating linear motion of the rack shaft to assist the linear movement of the rack shaft accompanying the steering operation.
  • the rotation transmission mechanism has a first pinion gear and a second pinion gear formed coaxially and integrally with a drive pinion gear rotated by an electric motor.
  • the drive gear mechanism having a pair of driven pinion gears rotated by the drive pinion gear, the driven gear mechanism that receives rotational torque from the drive gear mechanism to rotate the nut mechanism, and the pair of driven pinion gears are positioned apart from each other. To have a clip to hold.
  • the rotation transmission mechanism has a drive pinion gear that rotates the rotation torque of the electric motor by the electric motor, and a first pinion gear and a second pinion gear that are coaxially and integrally formed, and is rotated by the drive pinion gear. It is transmitted to the nut mechanism of the power conversion mechanism by a pair of driven pinion gears. Further, the pair of driven pinion gears are positioned and held by the clip.
  • the driven gear mechanism includes a first driven gear for low-speed rotation that meshes with the first pinion gear, a second driven gear for high-speed rotation that meshes with the second pinion gear, and a first driven gear.
  • a sliding screw mechanism having a rack shaft having a male screw portion on the outer periphery of the power conversion mechanism and a sliding nut mechanism rotatably screwed to the outer periphery of the rack shaft. It is desirable to do.
  • the sliding screw mechanism adopted in the power conversion mechanism disperses the surface pressure generated between the rack shaft and the sliding nut mechanism when assisting the reciprocating linear motion of the rack shaft.
  • the sliding nut mechanism is formed with a helical spline or a female screw having a lead angle exceeding the friction angle on the inner circumference, and a cylinder rotated by the rotation transmission mechanism and an outer circumference of the rack shaft.
  • the rack shaft is supported by a first bearing and a second bearing
  • the sliding nut is arranged between the pair of the first bearing and the second bearing so as to come into contact with the first bearing and to bring the sliding nut to the second bearing. It is desirable to have a first compression spring that urges toward the first bearing and a second compression spring that contacts the second bearing and urges the sliding nut toward the first bearing.
  • the electric power steering device when the power assist direction is reversed to the left or right, the electric power steering device is applied to the rack shaft by causing a momentary time lag until the electric motor stops and an effective reversal torque is generated.
  • a momentary decrease occurs in the auxiliary axial force, but in the electric power steering device of the present application, the auxiliary axial force generated in the rack shaft when the electric motor is rotated and reversed acts on the sliding nut. It is supplemented by the urging force of the compression spring and the second compression spring.
  • the rotational torque is transmitted between the electric motor and the power conversion mechanism by gears, and a pair of driven pinion gears that mesh with the driven gear mechanism are positioned and held by clips. Since it is not necessary to adjust the tension of the belt as in the belt transmission mechanism, the rotation transmission mechanism can be easily assembled to the drive conversion mechanism in the electric power steering device.
  • a large output power assist can be applied to the rack shaft when the vehicle is stopped or when the vehicle is running at low speed by switching the dog clutch without increasing the torque generated on the motor shaft. It can be realized, and high-speed power assist can be realized on the rack axis in steering when the vehicle is running.
  • the size of the device can be reduced by distributing the surface pressure between the rack shaft and the sliding nut mechanism, and the electric motor can be driven by the current battery mounted on a large vehicle. Even if it is operated, sufficient thrust can be applied to the rack shaft to assist steering, so it can be mounted on a large vehicle with a large vehicle weight.
  • the thrust is superior to the frictional force generated in the helical spline of the sliding nut or the male screw having a lead angle exceeding the friction angle and the helical spline of the cylinder or the female screw having a lead angle exceeding the friction angle. Since the sliding nut mechanism is easily rotated by the axial force of the rack shaft generated from the steering wheel side, the steering wheel is easily returned in the straight direction even if the axial force received from the steering wheel side is small, and the operation of the steering wheel (steering). The movements such as the wheels riding on obstacles and the steering wheel being taken off) are transmitted to the steering wheel, which makes it easier for the driver to transmit.
  • the electric power steering device even if the electric motor is temporarily stopped when the power assist direction is reversed, the assist force generated on the rack shaft by the urging force of the first compression spring or the second compression spring acting on the sliding nut. Since there is no decrease in power assist, the power assist force is not disrupted on the rack shaft during reversal.
  • FIG. 3 is an axial sectional view of the electric power steering device of the embodiment cut along the central axis of the rack axis.
  • FIGS. 1 to 3 An embodiment of the electric power steering device of the present application will be described with reference to FIGS. 1 to 3.
  • the first pinion gear 8a side is the tip direction or the front Fr
  • the second pinion gear 8b side is the base end direction or the rear Re, and others, upper: lower: left.
  • Direction: Right Up: Lo: Le: Ri.
  • the pinion gear 4a, the drive shaft 4b, and the idler gear 4c, which will be described later, are omitted.
  • the electric power steering device 1 shown in FIGS. 1 to 3 has a rotation transmission mechanism 2 and a sliding screw mechanism 3 which is a power conversion mechanism.
  • the rotation transmission mechanism 2 has a drive gear mechanism 4, a driven gear mechanism 5, and a pair of clips 6.
  • the drive gear mechanism 4 rotates to a drive pinion gear 4a, which is a spur gear coaxially and integrally fixed to a drive shaft 4b rotated by an electric motor (not shown), and to the drive shaft 4b on the tip side of the drive pinion gear 4a. It has an idler gear 4c that is freely attached and a pair of driven pinion gears 8 and 8 that are rotated by a drive pinion gear 4a.
  • the driven pinion gear 8 has a first pinion gear 8a which is a spur gear, a second pinion gear 8b which is a spur gear having a larger number of teeth and a larger tooth tip circle diameter than the first pinion gear 8a, and a driven shaft 8c, respectively.
  • the first and second pinion gears 8a and 8b are integrated in the front-rear direction by being coaxially fixed to the driven shaft 8c.
  • a mounting groove 8e for the clip 6 is formed on the outer circumference of the tip portion 8d of the driven shaft 8c projecting forward of the first pinion gear 8a.
  • the pair of clips 6 are made of a highly rigid metal or the like and have ring portions 6a and 6b at both ends, and as shown in FIG. 1, the pair of driven pinion gears 8 and 8 are one clip.
  • the ring portions 6a and 6b at both ends of 6 are fitted into the mounting grooves 8e of the tip portion 8d of the driven shaft 8c, respectively, and the ring portions 6a and 6b at both ends of the other clip 6 are the tip portions 8f shown in FIG.
  • the first pinion gears 8a and 8a are held in a pair of front and rear in a separated state in which the first pinion gears 8a and 8a do not mesh with each other and the second pinion gears 8b and 8b also do not mesh with each other.
  • the drive pinion gear 4a rotates the pair of driven pinion gears 8 and 8 by meshing with the second pinion gears 8b and 8b, respectively, and the idler gear 4c rotates with respect to the drive shaft 4b while meshing with the first pinion gears 8a and 8a.
  • the drive shaft 4b is fixed to the housing for accommodating the electric power steering device 1 via bearings (neither is shown).
  • the driven gear mechanism 5 has a smaller number of teeth than the first driven gear 9, which is a spur gear for low-speed rotation, and the first driven gear 9, and has a small tooth tip circle diameter. It has a second driven gear 10 for rotation and a clutch 11.
  • the first driven gear 9 has an inner cylinder portion 9a provided inside and a plurality of first dogs 9b provided on the inner cylinder portion 9a at equal intervals
  • the second driven gear 10 has an inner cylinder portion 9a. It has an inner cylinder portion 10a provided inside so as to have an inner diameter equal to the above, and a plurality of second dogs 10b provided in the inner cylinder portion 10a at equal intervals in the same number as the first dog 9b.
  • the clutch 11 includes a plurality of third dogs 11b provided on the tip end side of the tubular outer cylinder portion 11a at equal intervals in the same number as the first dog 9b, and the outside. It has a plurality of fourth dogs 11c provided at equal intervals on the base end side of the tubular portion 11a in the same number as the second dogs 10b.
  • a flange portion 11e provided with a groove portion 11d for engaging the tip of an electric actuator arm, which is an advancing / retreating mechanism (not shown), is integrally provided at the tip of the outer cylinder portion 11a.
  • a large number of slide grooves 11f extending in the central axis L0 direction of the dog clutch 11 are formed on the inner peripheral surface of the outer cylinder portion 11a.
  • the first driven gear 9 is supported by the outer cylinder portion 11a of the clutch 11 via the plurality of first dogs 9b
  • the second driven gear 10 is the base of the first driven gear 9 via the plurality of second dogs 10b. It is supported by the outer cylinder portion 11a while being adjacent to the end.
  • the third dog 11b and the fourth dog 11c are formed at positions facing each other on the outer cylinder portion 11a, and the axial distance between the facing third dog 11b and the fourth dog 11c is the first driven. It is formed to be equal to or larger than the total thickness of the gear 9 and the second driven gear 10 in the axial direction.
  • the clutch 11 shown in FIGS. 1 to 3 is configured to be slidable back and forth along the central axis L0 direction with respect to the first driven gear 9 and the second driven gear 10, and is arranged at three positions. .. That is, in the clutch 11, both the first dog 9b and the second dog 10b are the third dogs because the first driven gear 9 and the second driven gear 10 are arranged between the third dog 11b and the fourth dog 11c. A free arrangement that does not mesh with the 11b and the fourth dog 11c, or the third dog 11b is inserted between a pair of adjacent first dogs 9c of the first driven gear 9, and the fourth dog 11c is the second driven.
  • the first arrangement is not inserted between the pair of adjacent second dogs 10c of the gear 10, or the third dog 11b is not inserted between the pair of adjacent first dogs 9c of the first driven gear 9.
  • the dog 11c is selectively arranged at any position of the second arrangement inserted between the pair of adjacent second dogs 10c of the second driven gear 10.
  • the pair of first pinion gears 8a of the drive gear mechanism 4 meshes with the first driven gear 9, and the second pinion gear 8b meshes with the second driven gear 10.
  • the transmission of the rotational torque between the electric motor (not shown) and the sliding screw mechanism 3 is the drive pinion gear 4a, the driven pinion gear 8, the first and second driven gears 9,
  • a pair of driven pinion gears 8 which are performed by the 10 and the clutch 11 and mesh with the first and second driven gears 9 and 10 are easily positioned and held by the clip 6, so that a belt such as a belt transmission mechanism as in the prior art is used. Since it is not necessary to adjust the tension of the above, it becomes easy to assemble the rotation transmission mechanism to the drive conversion mechanism in the electric power steering device.
  • the sliding screw mechanism 3 has a rack shaft 15 having a male screw portion 15a on the outer periphery and a sliding nut mechanism 16.
  • the sliding nut mechanism 16 is composed of a sliding nut 17 and a cylinder 18.
  • the sliding nut 17 has a female threaded portion 17a that meshes with the male threaded portion 15a on the inside, and has a helical spline 17b on the outer periphery.
  • the cylinder 18 has a large number of helical splines 18a that mesh with the helical splines 17b inside, is formed so as to extend in the direction of the central axis L0 of the cylinder, and has a large number of slide grooves 18b that engage with a large number of slide grooves 11f of the clutch 11. It has on the outer circumference.
  • the cylinder 18 is inserted inside the clutch 11 with a large number of slide grooves 18b engaged with the slide grooves 11f, and holds the clutch 11 slidably in the direction along the central axis L0.
  • the clutch 11 slides back and forth with respect to the cylinder by being pressed back and forth by an electric actuator arm (advancing and retreating mechanism (not shown)) that engages with the groove portion 11d of the flange portion 11e.
  • the advance / retreat mechanism (not shown) may be realized by a solenoid mechanism or the like provided on the clutch 11.
  • a male screw having a lead angle exceeding the friction angle is formed on the outer periphery of the sliding nut 17 instead of the helical spline 17b, and a female screw having a lead angle exceeding the friction angle is formed instead of the helical spline 18a.
  • the slip nut 17 may be engaged with the cylinder 18 via the male screw and the female screw formed inside the cylinder 18 and having a lead angle exceeding the friction angle.
  • a first compression spring 19 and a second compression spring 20, which are coil springs, are arranged before and after the sliding nut 17 screwed to the rack shaft 15, and further, before and after the first compression spring 19 and a second compression spring 20.
  • the 1 washer 21 and the 2nd washer 22 are arranged respectively.
  • the rack shaft 15 shown in FIG. 2 is screwed with a sliding nut 17, and is screwed to the cylinder 18 with the first compression spring 19, the second compression spring 20, the first washer 21, and the second washer 22 arranged. And, it is inserted into the clutch 11 holding the first driven gear 9 and the second driven gear 10 together with the cylinder 18.
  • the rack shaft 15 having both ends protruding in front of the cylinder 18 and rear of the second driven gear 10 has a first bearing member 23 which is a first bearing and a second bearing which is a second bearing in the front and rear. It is held by a member 24 and attached to a housing (not shown) via a first ball bearing 25 and a second ball bearing 26.
  • the first bearing member 23 shown in FIG. 3 is formed in a cylindrical shape, has a bearing fixing portion 23a on the outer periphery of the tip, and has a flange portion 23b for positioning the first ball bearing 25 rearward at the base end portion thereof.
  • the circular rack shaft holding portion 23c is provided inside the bearing fixing portion 23a
  • the bottom portion 23d is provided inside the flange portion 23b
  • the first washer 21 is engaged with the base end side of the bottom portion. It has a groove 23e.
  • the second bearing member 24 is formed in a cylindrical shape, has a bearing fixing portion 24a on the outer periphery of the base end, and has a flange portion 24b at the tip portion thereof for positioning the second ball bearing 26 forward.
  • a cylindrical rack shaft holding portion 24c is provided inside the fixing portion 24a
  • a bottom portion 24d is provided inside the flange portion 24b
  • a circular groove 24e for engaging the second washer 22 is provided on the tip end side of the bottom portion.
  • the rack shafts 15 shown in FIGS. 2 and 3 were inserted into the rack shaft holding portions 23c and 24c of the first and second bearing members 23 and 24, respectively, and the cylinder 18 was held by the circular grooves 23e and 24e.
  • the tip and base ends are sandwiched by the first and second washers 21 and 22.
  • the first and second bearing members 23 and 24 rotate to the housing (not shown) together with the rack shaft 15 by being attached to the housing (not shown) via the first ball bearings 25 and 26.
  • the stopper 11g formed under the flange portion 11e and the flange portion 18c formed near the tip of the cylinder 18 come into contact with each other when sliding forward. As a result, it is positioned forward, and when it slides backward, the base end portion 11h comes into contact with the tip portion 24f of the second bearing member 24 and is positioned rearward.
  • the first compression spring 19 shown in FIG. 2 is compressed to the front end portion of the first washer 21 and the sliding nut 17 to urge the sliding nut 17 toward the second bearing member 24 and to urge the sliding nut 17 to the second bearing member 24.
  • the two compression springs 20 are compressed by the rear end portion of the sliding nut 17 and the second washer 22 to urge the sliding nut 17 toward the first bearing member 23 with the same urging force as the first compression spring 19.
  • the sliding nut 17 is held at the center of the rack shaft 15 by the balance of the urging forces of both compression springs.
  • the operation of the electric power steering device 1 of this embodiment will be described with reference to FIGS. 1 to 3.
  • the rack shaft 15 shown in FIG. 1 moves back and forth as the driver steers the vehicle left and right by steering (not shown).
  • An electric motor (not shown) rotates the drive pinion gear 4a in accordance with the advancing / retreating direction of the rack shaft 15 based on steering, and simultaneously rotates both the first driven gear 9 and the second driven gear 10 via the driven pinion gear 8. Let me.
  • the third dog 11b and the fourth dog 11c do not mesh with any of the first dog 9b of the first driven gear 9 and the second dog 10b of the second driven gear 10, and the first It is arranged in a "free arrangement” that does not receive rotational torque from any of the 1st and 2nd driven gears 9 and 10.
  • the clutch 11 is slid rearward by an electric actuator arm (not shown) and the third dog 11b is arranged in the "first arrangement" in which the first dog 9b of the first driven gear 9 is engaged, the clutch 11 is electrically operated (not shown). As the motor rotates, it receives a large torque from the first driven gear 9 and rotates at a low speed.
  • the clutch 11 shown in FIGS. 1 and 3 is slid forward by an electric actuator arm (not shown), and the fourth dog 11c is arranged in the "second arrangement" in which the second dog 10b of the second driven gear 10 meshes with the second dog 10b.
  • the clutch 11 receives a torque smaller than that of the first driven gear 9 from the second driven gear 10 as the electric motor (not shown) rotates, and rotates at a high speed.
  • the clutch 11 is automatically arranged in the first arrangement by the electric actuator mechanism at a low speed such as 0 km to 10 km / h according to the vehicle speed detected by the vehicle speed detection device (not shown), and the second arrangement when the speed exceeds 10 km / h. It is desirable to be able to switch automatically to.
  • the clutch 11 shown in FIGS. 1 and 3 is a cylinder that meshes inward through a slide groove 11f based on the rotation of an electric motor (not shown) and the selective arrangement of the "first arrangement" or the "second arrangement”. 18 is rotated. At that time, the sliding nut 17 that meshes with the cylinder 18 via the helical spline 18a (or a female screw having a lead angle exceeding the friction angle) and the helical spline 17b (or a male screw having a lead angle exceeding the friction angle) is attached to the cylinder 18. While rotating relative to each other, it moves back and forth along the central axis L0.
  • the sliding nut 17 rotates while advancing and retreating back and forth to advance and retreat the rack shaft 15 that meshes with the female screw 17a and the male screw 15a, thereby moving the rack shaft 15 back and forth along the central axis L0.
  • a large axial force is generated on the rack shaft 15 at a low speed by arranging the clutch 11 in the "first arrangement" in steering steering of a stopped vehicle or running at a low speed.
  • the rack shaft 15 is generated with an axial force smaller than that in the "first arrangement” at a high speed to assist the steering.
  • the thrust is superior to the frictional force generated between the sliding nut 17 and the cylinder 18, and the screw used for meshing is a helical spline or a screw having a lead angle exceeding the frictional angle.
  • the screw used for meshing is a helical spline or a screw having a lead angle exceeding the frictional angle.
  • the rack shafts of FIGS. 1 and 3 have the steering wheels based on the setting of the caster angle and the trail amount of the steering wheels (not shown).
  • the steering wheel side receives an axial force in the opposite direction to that during steering.
  • the sliding nut 17 has a helical spline 17b (or a male screw having a lead angle exceeding the friction angle) and a helical spline 18a (or a lead angle exceeding the friction angle) of the cylinder 18.
  • the rack shaft 15 rotates relative to the rack shaft 15 and the cylinder 18 without becoming independent, and the rack shaft 15 is moved forward and backward along the central axis L0 in the direction opposite to that during steering. , Return the steering wheel to the straight direction.
  • the sliding nut 17 arranged at a position deviated from the center position of the rack shaft 15 to the left or right side compresses one of the first compression spring 19 and the second compression spring 20. Therefore, according to the electric power steering device of the present embodiment, when the driver switches the steering steering direction, the compressed first compression spring 19 or the second compression spring 20 is driven by a force that tries to return to the original position. By applying torque in the reversing direction (reversing direction of the electric motor) to the sliding nut 17, a decrease in the axial force applied to the rack shaft 15 from the electric motor (not shown) acts on the sliding nut 17.
  • the rack shaft 15 does not break the auxiliary force when the steering direction is reversed.

Abstract

Provided is an electric power steering device in which a rotation transmission mechanism can be easily assembled with respect to a drive conversion mechanism within the electric power steering device. An electric power steering device (1) comprises a rotation transmission mechanism (2) that rotates a nut mechanism (16) by means of rotation of an electric motor, and a motive power conversion mechanism (3) that converts a rotation motion of the nut mechanism to a linear reciprocating motion of a rack shaft (15) so as to assist a linear motion of the rack shaft (15), wherein the rotation transmission mechanism (2) includes: a driving gear mechanism (4) having a driving pinion gear (4a) that rotates by means of the electric motor, and a pair of driven pinion gears (8) which include first and second pinion gears (8a, 8b) formed coaxially and integrally, and which rotate by means of a driving pinion gear (7a); a driven gear mechanism (5) that receives a rotational torque from the driving gear mechanism (4) so as to rotate the nut mechanism (16); and a clip (6) that positions and holds the pair of driven pinion gears (8) in a state of being spaced apart.

Description

電動パワーステアリング装置Electric power steering device
　装置内の駆動変換機構に対する回動伝達機構の組み付けが容易な電動パワーステアリング装置に関する技術。 Technology related to electric power steering devices that makes it easy to assemble a rotation transmission mechanism to a drive conversion mechanism inside the device.
　引用文献１には、図２と［００２５］に示すように電動モータの回転運動をベルト伝達機構及びボールねじ機構によってラック軸の直線運動に変換してドライバーによるステアリング動作を補助する電動パワーステアリング装置が開示されている。 In Reference 1, as shown in FIGS. 2 and 2, an electric power steering device that assists the driver in steering operation by converting the rotational motion of the electric motor into a linear motion of the rack axis by a belt transmission mechanism and a ball screw mechanism. Is disclosed.
特開２０１４－２４３５７号公報Japanese Unexamined Patent Publication No. 2014-24357
　ベルト伝達機構を採用した電動パワーステアリング装置は、電動モータによって回動する主動プーリとボールねじ機構側のボールナットに一体化された従動プーリとの間に設置したベルトを介して電動モータの回動トルクをボールナットに伝達する。 The electric power steering device that employs a belt transmission mechanism rotates the electric motor via a belt installed between the main pulley that is rotated by the electric motor and the driven pulley that is integrated with the ball nut on the ball screw mechanism side. The torque is transmitted to the ball nut.
　しかし、ベルト伝達機構を採用した電動パワーステアリング装置の組み立てにおいては、ベルトに必要な張力が得られるように調整しながら電動モータとボールねじ機構を装置内に組み付ける必要があるため、作業工数の増大を招く問題がある。 However, when assembling an electric power steering device that employs a belt transmission mechanism, it is necessary to assemble the electric motor and ball screw mechanism inside the device while adjusting so that the tension required for the belt can be obtained, which increases the work manpower. There is a problem that leads to.
　上記課題に鑑み、本願発明は、装置内の駆動変換機構に対する回動伝達機構の組み付けが容易な電動パワーステアリング装置を提供するものである。 In view of the above problems, the present invention provides an electric power steering device in which a rotation transmission mechanism can be easily assembled to a drive conversion mechanism in the device.
　電動モータの回動を伝達してナット機構を回動させる回動伝達機構と、ナット機構の回動運動をラック軸の往復直進運動に変換してステアリング操作に伴うラック軸の直線運動を補助する動力変換機構と、を備えた電動パワーステアリング装置において、前記回動伝達機構は、電動モータによって回動する駆動ピニオンギヤと、同軸かつ一体に形成された第１ピニオンギヤ及び第２ピニオンギヤを有し、前記駆動ピニオンギヤによって回動する一対の従動ピニオンギヤを有する駆動歯車機構と、駆動歯車機構から回動トルクを受けてナット機構を回動させる従動歯車機構と、前記一対の従動ピニオンギヤを互いに離間した状態に位置決め保持するクリップと、を有するようにした。 A rotation transmission mechanism that transmits the rotation of the electric motor to rotate the nut mechanism, and a rotation transmission mechanism that converts the rotational movement of the nut mechanism into a reciprocating linear motion of the rack shaft to assist the linear movement of the rack shaft accompanying the steering operation. In an electric power steering device including a power conversion mechanism, the rotation transmission mechanism has a first pinion gear and a second pinion gear formed coaxially and integrally with a drive pinion gear rotated by an electric motor. The drive gear mechanism having a pair of driven pinion gears rotated by the drive pinion gear, the driven gear mechanism that receives rotational torque from the drive gear mechanism to rotate the nut mechanism, and the pair of driven pinion gears are positioned apart from each other. To have a clip to hold.
　（作用）回動伝達機構は、電動モータによる回動トルクを電動モータによって回動する駆動ピニオンギヤと、同軸かつ一体に形成された第１ピニオンギヤ及び第２ピニオンギヤを有し、前記駆動ピニオンギヤによって回動する一対の従動ピニオンギヤによって動力変換機構のナット機構に伝達する。また、一対の従動ピニオンギヤは、クリップによって位置決め保持される。 (Action) The rotation transmission mechanism has a drive pinion gear that rotates the rotation torque of the electric motor by the electric motor, and a first pinion gear and a second pinion gear that are coaxially and integrally formed, and is rotated by the drive pinion gear. It is transmitted to the nut mechanism of the power conversion mechanism by a pair of driven pinion gears. Further, the pair of driven pinion gears are positioned and held by the clip.
　また、電動パワーステアリング装置において、前記従動歯車機構は、前記第１ピニオンギヤに噛み合う低速回動用の第１従動歯車と、前記第２ピニオンギヤに噛み合う高速回動用の第２従動歯車と、第１従動歯車または第２従動歯車の回動を前記シリンダーに選択的に伝達するクラッチと、を有することが望ましい。 Further, in the electric power steering device, the driven gear mechanism includes a first driven gear for low-speed rotation that meshes with the first pinion gear, a second driven gear for high-speed rotation that meshes with the second pinion gear, and a first driven gear. Alternatively, it is desirable to have a clutch that selectively transmits the rotation of the second driven gear to the cylinder.
　（作用）シリンダーに回動トルクを伝達する従動歯車を低速回動用の第１従動歯車に切り換えると、シリンダーに大きな回動トルクが付与されてラック軸に大きな軸力が低速で付与され、シリンダーに回動トルクを伝達する従動歯車を高速回動用の第２従動歯車に切り換えると、シリンダーに小さな回動トルクが付与されてラック軸に小さな軸力が高速で付与される。 (Action) When the driven gear that transmits the rotational torque to the cylinder is switched to the first driven gear for low-speed rotation, a large rotational torque is applied to the cylinder, a large axial force is applied to the rack shaft at low speed, and the cylinder When the driven gear that transmits the rotational torque is switched to the second driven gear for high-speed rotation, a small rotational torque is applied to the cylinder and a small axial force is applied to the rack shaft at high speed.
　また、電動パワーステアリング装置において、前記動力変換機構を外周に雄ねじ部を備えた前記ラック軸と、前記ラック軸の外周に回動可能に螺着されたすべりナット機構と、を有するすべりねじ機構とすることが望ましい。 Further, in an electric power steering device, a sliding screw mechanism having a rack shaft having a male screw portion on the outer periphery of the power conversion mechanism and a sliding nut mechanism rotatably screwed to the outer periphery of the rack shaft. It is desirable to do.
　（作用）動力変換機構に採用されたすべりねじ機構により、ラック軸の往復直線運動を補助する際にラック軸とすべりナット機構との間に発生する面圧が分散される。 (Action) The sliding screw mechanism adopted in the power conversion mechanism disperses the surface pressure generated between the rack shaft and the sliding nut mechanism when assisting the reciprocating linear motion of the rack shaft.
　また、電動パワーステアリング装置において前記すべりナット機構が、内周にヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雌ねじを形成されると共に前記回動伝達機構によって回動するシリンダーと、前記ラック軸の外周に螺着され、更に外周に形成されたヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雄ねじを介してシリンダーのヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雌ねじに螺着されたすべりナットと、を有するようにすることが望ましい。 Further, in the electric power steering device, the sliding nut mechanism is formed with a helical spline or a female screw having a lead angle exceeding the friction angle on the inner circumference, and a cylinder rotated by the rotation transmission mechanism and an outer circumference of the rack shaft. A slip nut screwed to the helical spline of the cylinder or a female screw having a lead angle exceeding the friction angle via a helical spline formed on the outer circumference or a male screw having a lead angle exceeding the friction angle. It is desirable to have.
　（作用）ドライバーが車両の方向転換を終えてステアリングを手放し、操舵車輪のキャスター角とトレール量の設定に基づいた操舵車輪が直進方向に戻る際に、車輪側からラック軸に軸方向の力である軸力が作用する場合において、すべりナットのヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雄ねじとシリンダーのヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雌ねじに発生する摩擦力より推力が勝り、軸力を受けて直線運動をするラック軸によってすべりナットが回動し、すべりナットの回動に伴ってシリンダーが回動し、操舵車輪が直進方向に戻りやすくなる。 (Action) When the driver finishes turning the vehicle and releases the steering wheel, and the steering wheel returns to the straight direction based on the setting of the caster angle and trail amount of the steering wheel, an axial force is applied from the wheel side to the rack axis. When a certain axial force acts, the thrust is superior to the frictional force generated in the helical spline of the sliding nut or the male screw having a lead angle exceeding the friction angle and the helical spline of the cylinder or the female screw having a lead angle exceeding the friction angle, and the shaft. The sliding nut is rotated by the rack shaft that receives a force and moves linearly, and the cylinder is rotated with the rotation of the sliding nut, so that the steering wheel can easily return to the straight direction.
　また、電動パワーステアリング装置において。前記ラック軸は、第１軸受と第２軸受によって支持され、前記すべりナットは、前記一対の第１軸受と第２軸受の間に配置され、第１軸受に接触すると共にすべりナットを第２軸受に向けて付勢する第１圧縮ばねと、第２軸受に接触すると共にすべりナットを第１軸受に向けて付勢する第２圧縮ばねと、有するようにすることが望ましい。 Also, in the electric power steering device. The rack shaft is supported by a first bearing and a second bearing, and the sliding nut is arranged between the pair of the first bearing and the second bearing so as to come into contact with the first bearing and to bring the sliding nut to the second bearing. It is desirable to have a first compression spring that urges toward the first bearing and a second compression spring that contacts the second bearing and urges the sliding nut toward the first bearing.
　（作用）ドライバーが車両の方向転換を終えてステアリングを手放した際にすべりナットが、第１圧縮ばねと第２圧縮ばねの付勢力の釣り合いによってラック軸の中央に変位される。 (Action) When the driver finishes turning the vehicle and releases the steering wheel, the sliding nut is displaced to the center of the rack shaft by the balance of the urging forces of the first compression spring and the second compression spring.
　また、一般に電動パワーステアリング装置は、パワーアシスト方向を左右いずれかに反転させる場合において、電動モータが停止して有効な反転トルクを発生させるまでに一瞬のタイムラグが生じることで、ラック軸へ付与される軸力の補助に一瞬の低下が生じるが、本願の電動パワーステアリング装置においては、電動モータの回動反転時にラック軸に発生する補助的な軸力の低下が、すべりナットに作用する第１圧縮ばね及び第２圧縮ばねの付勢力によって補われる。 Further, in general, when the power assist direction is reversed to the left or right, the electric power steering device is applied to the rack shaft by causing a momentary time lag until the electric motor stops and an effective reversal torque is generated. A momentary decrease occurs in the auxiliary axial force, but in the electric power steering device of the present application, the auxiliary axial force generated in the rack shaft when the electric motor is rotated and reversed acts on the sliding nut. It is supplemented by the urging force of the compression spring and the second compression spring.
　電動パワーステアリング装置によれば、電動モータと動力変換機構との間の回動トルクの伝達が歯車によって行われ、従動歯車機構に噛み合う一対の従動ピニオンギヤがクリップによって位置決め保持される事で、従来技術のようにベルト伝達機構のようなベルトの張力調整が不要になるため、電動パワーステアリング装置内の駆動変換機構に対する回動伝達機構の組み付けが、容易になる。 According to the electric power steering device, the rotational torque is transmitted between the electric motor and the power conversion mechanism by gears, and a pair of driven pinion gears that mesh with the driven gear mechanism are positioned and held by clips. Since it is not necessary to adjust the tension of the belt as in the belt transmission mechanism, the rotation transmission mechanism can be easily assembled to the drive conversion mechanism in the electric power steering device.
　また、電動パワーステアリング装置によれば、モータ軸に発生するトルクそのものを大きくしなくても、ドッグクラッチの切り替えによって、停止または低速走行時の車両の方向転換におけるラック軸に大出力のパワーアシストが実現出来、更に車両走行時の操舵におけるラック軸に高速のパワーアシストが実現出来る。 In addition, according to the electric power steering device, a large output power assist can be applied to the rack shaft when the vehicle is stopped or when the vehicle is running at low speed by switching the dog clutch without increasing the torque generated on the motor shaft. It can be realized, and high-speed power assist can be realized on the rack axis in steering when the vehicle is running.
　また、電動パワーステアリング装置によれば、ラック軸とすべりナット機構との間の面圧が分散されることによって装置のサイズを小型化出来ると共に、大型車に搭載された現行のバッテリーによって電動モータを動作させてもステアリング操舵の補助に十分な推力をラック軸に与えることが出来るため、車重の大きな大型車への搭載が可能になる。 In addition, according to the electric power steering device, the size of the device can be reduced by distributing the surface pressure between the rack shaft and the sliding nut mechanism, and the electric motor can be driven by the current battery mounted on a large vehicle. Even if it is operated, sufficient thrust can be applied to the rack shaft to assist steering, so it can be mounted on a large vehicle with a large vehicle weight.
　また、電動パワーステアリング装置によれば、すべりナットのヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雄ねじとシリンダーのヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雌ねじに発生する摩擦力より推力が勝り、操舵車輪側から発生したラック軸の軸力によってすべりナット機構が回動し易くなるため、操舵車輪側から受ける軸力が小さくても操舵車輪が直進方向に戻り易くなり、操舵車輪の動作（操舵車輪が障害物に乗り上げたりハンドルを取られる等の動作）がステアリングに伝わることでドライバーに伝わり易くなる。 Further, according to the electric power steering device, the thrust is superior to the frictional force generated in the helical spline of the sliding nut or the male screw having a lead angle exceeding the friction angle and the helical spline of the cylinder or the female screw having a lead angle exceeding the friction angle. Since the sliding nut mechanism is easily rotated by the axial force of the rack shaft generated from the steering wheel side, the steering wheel is easily returned in the straight direction even if the axial force received from the steering wheel side is small, and the operation of the steering wheel (steering). The movements such as the wheels riding on obstacles and the steering wheel being taken off) are transmitted to the steering wheel, which makes it easier for the driver to transmit.
　また、電動パワーステアリング装置によれば、パワーアシスト方向の反転時に電動モータに一時停止があっても、すべりナットに作用する第１圧縮ばねあるいは第２圧縮ばねの付勢力によってラック軸に生じるアシスト力の低下が無いため、反転時のラック軸においてパワーアシスト力の寸断が発生しない。 Further, according to the electric power steering device, even if the electric motor is temporarily stopped when the power assist direction is reversed, the assist force generated on the rack shaft by the urging force of the first compression spring or the second compression spring acting on the sliding nut. Since there is no decrease in power assist, the power assist force is not disrupted on the rack shaft during reversal.
実施例の電動パワーステアリング装置の斜視図。The perspective view of the electric power steering apparatus of an Example. 実施例の電動パワーステアリング装置の分解斜視図。An exploded perspective view of the electric power steering device of the embodiment. 実施例の電動パワーステアリング装置をラック軸の中心軸線に沿って切断した軸方向断面図。FIG. 3 is an axial sectional view of the electric power steering device of the embodiment cut along the central axis of the rack axis.
　図１から図３により本願の電動パワーステアリング装置の実施形態を説明する。各図においては、後述する第１及び第２ピニオンギヤ８ａ，８ｂにおいて、第１ピニオンギヤ８ａ側を先端方向または前方Ｆｒ、第２ピニオンギヤ８ｂ側を基端方向または後方Ｒｅ、その他、上方：下方：左方：右方＝Ｕｐ：Ｌｏ：Ｌｅ：Ｒｉとして説明する。尚、図２と図３においては、後述するピニオンギヤ４ａ、駆動軸４ｂ及びアイドラーギヤ４ｃが省略されている。 An embodiment of the electric power steering device of the present application will be described with reference to FIGS. 1 to 3. In each figure, in the first and second pinion gears 8a and 8b described later, the first pinion gear 8a side is the tip direction or the front Fr, the second pinion gear 8b side is the base end direction or the rear Re, and others, upper: lower: left. Direction: Right = Up: Lo: Le: Ri. In addition, in FIGS. 2 and 3, the pinion gear 4a, the drive shaft 4b, and the idler gear 4c, which will be described later, are omitted.
　図１から図３に示す電動パワーステアリング装置１は、回動伝達機構２と、動力変換機構であるすべりねじ機構３を有する。 The electric power steering device 1 shown in FIGS. 1 to 3 has a rotation transmission mechanism 2 and a sliding screw mechanism 3 which is a power conversion mechanism.
　回動伝達機構２は、駆動歯車機構４と、従動歯車機構５と、一対のクリップ６を有する。駆動歯車機構４は、電動モータ（図示せず）によって回動する駆動軸４ｂに同軸かつ一体に固定された平歯車である駆動ピニオンギヤ４ａと、駆動ピニオンギヤ４ａの先端側で駆動軸４ｂに回動自在に取り付けられたアイドラーギヤ４ｃと、駆動ピニオンギヤ４ａによって回動する一対の従動ピニオンギヤ８、８を有する。従動ピニオンギヤ８は、平歯車である第１ピニオンギヤ８ａと、第１ピニオンギヤ８ａよりも歯数が多くかつ歯先円直径の大きな平歯車である第２ピニオンギヤ８ｂと、従動軸８ｃをそれぞれ有する。第１及び第２ピニオンギヤ８ａ、８ｂは、従動軸８ｃに同軸に固定されることによって前後に一体化される。第１ピニオンギヤ８ａの前方に突出する従動軸８ｃの先端部８ｄの外周には、クリップ６の取付溝８ｅが形成される。 The rotation transmission mechanism 2 has a drive gear mechanism 4, a driven gear mechanism 5, and a pair of clips 6. The drive gear mechanism 4 rotates to a drive pinion gear 4a, which is a spur gear coaxially and integrally fixed to a drive shaft 4b rotated by an electric motor (not shown), and to the drive shaft 4b on the tip side of the drive pinion gear 4a. It has an idler gear 4c that is freely attached and a pair of driven pinion gears 8 and 8 that are rotated by a drive pinion gear 4a. The driven pinion gear 8 has a first pinion gear 8a which is a spur gear, a second pinion gear 8b which is a spur gear having a larger number of teeth and a larger tooth tip circle diameter than the first pinion gear 8a, and a driven shaft 8c, respectively. The first and second pinion gears 8a and 8b are integrated in the front-rear direction by being coaxially fixed to the driven shaft 8c. A mounting groove 8e for the clip 6 is formed on the outer circumference of the tip portion 8d of the driven shaft 8c projecting forward of the first pinion gear 8a.
　図２に示すように一対のクリップ６は、剛性の高い金属等で形成されて両端にリング部６ａ、６ｂを有し、図１に示すように一対の従動ピニオンギヤ８，８は、一方のクリップ６の両端のリング部６ａ、６ｂをそれぞれ従動軸８ｃの先端部８ｄの取付溝８ｅに嵌めこまれ、かつもう一方のクリップ６の両端のリング部６ａ、６ｂをそれぞれ図３に示す先端部８ｆの取付溝８ｇに嵌めこまれることによって、第１ピニオンギヤ８ａ，８ａが互いに噛み合わず、かつ第２ピニオンギヤ８ｂ、８ｂも互いに噛み合わない離間した状態に前後１対で保持される。駆動ピニオンギヤ４ａは、第２ピニオンギヤ８ｂ、８ｂにそれぞれ噛み合うことによって、一対の従動ピニオンギヤ８，８を回動させ、アイドラーギヤ４ｃは、第１ピニオンギヤ８ａ，８ａに噛み合いつつ駆動軸４ｂに対して回動することによって、一対の従動ピニオンギヤ８，８と駆動ピニオンギヤ４ａを位置決めする。駆動軸４ｂは、軸受を介して電動パワーステアリング装置１を収納するハウジングに固定される（いずれも図示せず）。 As shown in FIG. 2, the pair of clips 6 are made of a highly rigid metal or the like and have ring portions 6a and 6b at both ends, and as shown in FIG. 1, the pair of driven pinion gears 8 and 8 are one clip. The ring portions 6a and 6b at both ends of 6 are fitted into the mounting grooves 8e of the tip portion 8d of the driven shaft 8c, respectively, and the ring portions 6a and 6b at both ends of the other clip 6 are the tip portions 8f shown in FIG. By being fitted into the mounting groove 8g of the above, the first pinion gears 8a and 8a are held in a pair of front and rear in a separated state in which the first pinion gears 8a and 8a do not mesh with each other and the second pinion gears 8b and 8b also do not mesh with each other. The drive pinion gear 4a rotates the pair of driven pinion gears 8 and 8 by meshing with the second pinion gears 8b and 8b, respectively, and the idler gear 4c rotates with respect to the drive shaft 4b while meshing with the first pinion gears 8a and 8a. By moving, the pair of driven pinion gears 8 and 8 and the drive pinion gear 4a are positioned. The drive shaft 4b is fixed to the housing for accommodating the electric power steering device 1 via bearings (neither is shown).
　図１～図３に示すように従動歯車機構５は、低速回動用の平歯車である第１従動歯車９と、第１従動歯車９よりも歯数が少なく、かつ歯先円直径の小さな高速回動用の第２従動歯車１０と、クラッチ１１を有する。第１従動歯車９は、内側に設けられた内筒部９ａと、内筒部９ａに等間隔で複数設けられた第１ドッグ９ｂとを有し、第２従動歯車１０は、内筒部９ａと等しい内径を有するように内側に設けられた内筒部１０ａと、内筒部１０ａに等間隔で第１ドッグ９ｂと同じ数だけ設けられた複数の第２ドッグ１０ｂとを有する。 As shown in FIGS. 1 to 3, the driven gear mechanism 5 has a smaller number of teeth than the first driven gear 9, which is a spur gear for low-speed rotation, and the first driven gear 9, and has a small tooth tip circle diameter. It has a second driven gear 10 for rotation and a clutch 11. The first driven gear 9 has an inner cylinder portion 9a provided inside and a plurality of first dogs 9b provided on the inner cylinder portion 9a at equal intervals, and the second driven gear 10 has an inner cylinder portion 9a. It has an inner cylinder portion 10a provided inside so as to have an inner diameter equal to the above, and a plurality of second dogs 10b provided in the inner cylinder portion 10a at equal intervals in the same number as the first dog 9b.
　図１～図３に示すようにクラッチ１１は、筒状に形成された外筒部１１ａの先端側に等間隔で第１ドッグ９ｂと同じ数だけ設けられた複数の第３ドッグ１１ｂと、外筒部１１ａの基端側に等間隔で第２ドッグ１０ｂと同じ数だけ設けられた複数の第４ドッグ１１ｃと、を有する。外筒部１１ａの先端には、後述する図示しない進退機構である電動アクチュエータアームの先端を係合させる溝部１１ｄを備えたフランジ部１１ｅが一体に設けられている。外筒部１１ａの内周面には、ドッグクラッチ１１の中心軸線Ｌ０方向に延びる多数のスライド溝１１ｆが形成されている。 As shown in FIGS. 1 to 3, the clutch 11 includes a plurality of third dogs 11b provided on the tip end side of the tubular outer cylinder portion 11a at equal intervals in the same number as the first dog 9b, and the outside. It has a plurality of fourth dogs 11c provided at equal intervals on the base end side of the tubular portion 11a in the same number as the second dogs 10b. A flange portion 11e provided with a groove portion 11d for engaging the tip of an electric actuator arm, which is an advancing / retreating mechanism (not shown), is integrally provided at the tip of the outer cylinder portion 11a. A large number of slide grooves 11f extending in the central axis L0 direction of the dog clutch 11 are formed on the inner peripheral surface of the outer cylinder portion 11a.
　第１従動歯車９は、複数の第１ドッグ９ｂを介してクラッチ１１の外筒部１１ａに支持され、第２従動歯車１０は、複数の第２ドッグ１０ｂを介し、第１従動歯車９の基端に隣接しつつ外筒部１１ａに支持される。第３ドッグ１１ｂ及び第４ドッグ１１ｃは、外筒部１１ａ上においてそれぞれ対向する位置に間隔を開けて形成され、対向する第３ドッグ１１ｂと第４ドッグ１１ｃの軸方向の間隔は、第１従動歯車９と第２従動歯車１０の軸方向における厚さの合計以上に形成される。 The first driven gear 9 is supported by the outer cylinder portion 11a of the clutch 11 via the plurality of first dogs 9b, and the second driven gear 10 is the base of the first driven gear 9 via the plurality of second dogs 10b. It is supported by the outer cylinder portion 11a while being adjacent to the end. The third dog 11b and the fourth dog 11c are formed at positions facing each other on the outer cylinder portion 11a, and the axial distance between the facing third dog 11b and the fourth dog 11c is the first driven. It is formed to be equal to or larger than the total thickness of the gear 9 and the second driven gear 10 in the axial direction.
　図１から図３に示すクラッチ１１は、第１従動歯車９と第２従動歯車１０に対して中心軸線Ｌ０方向に沿って前後にスライド可能に構成されると共に、３通りの位置に配置される。即ち、クラッチ１１は、第１従動歯車９と第２従動歯車１０が第３ドッグ１１ｂと第４ドッグ１１ｃの間に配置されることによって第１ドッグ９ｂ及び第２ドッグ１０ｂのいずれも第３ドッグ１１ｂ及び第４ドッグ１１ｃに噛み合わないフリー配置、または、第３ドッグ１１ｂが、第１従動歯車９の隣り合う一対の第１ドッグ９ｃの間に挿入されると共に第４ドッグ１１ｃが、第２従動歯車１０の隣り合う一対の第２ドッグ１０ｃの間に挿入されない第１配置、または、第３ドッグ１１ｂが第１従動歯車９の隣り合う一対の第１ドッグ９ｃの間に挿入されずに第４ドッグ１１ｃが、第２従動歯車１０の隣り合う一対の第２ドッグ１０ｃの間に挿入される第２配置のいずれかの位置に選択的に配置される。 The clutch 11 shown in FIGS. 1 to 3 is configured to be slidable back and forth along the central axis L0 direction with respect to the first driven gear 9 and the second driven gear 10, and is arranged at three positions. .. That is, in the clutch 11, both the first dog 9b and the second dog 10b are the third dogs because the first driven gear 9 and the second driven gear 10 are arranged between the third dog 11b and the fourth dog 11c. A free arrangement that does not mesh with the 11b and the fourth dog 11c, or the third dog 11b is inserted between a pair of adjacent first dogs 9c of the first driven gear 9, and the fourth dog 11c is the second driven. The first arrangement is not inserted between the pair of adjacent second dogs 10c of the gear 10, or the third dog 11b is not inserted between the pair of adjacent first dogs 9c of the first driven gear 9. The dog 11c is selectively arranged at any position of the second arrangement inserted between the pair of adjacent second dogs 10c of the second driven gear 10.
　図１及び図３に示すように駆動歯車機構４の一対の第１ピニオンギヤ８ａは、第１従動歯車９に噛み合い、かつ第２ピニオンギヤ８ｂは、第２従動歯車１０に噛み合った状態となるようにクリップ６によって位置決め保持される。本実施例の電動パワーステアリング装置１によれば、図示しない電動モータと、すべりねじ機構３との間の回動トルクの伝達が駆動ピニオンギヤ４ａ、従動ピニオンギヤ８，第１及び第２従動歯車９，１０及びクラッチ１１によって行われ、第１及び第２従動歯車９，１０に噛み合う一対の従動ピニオンギヤ８がクリップ６によって容易に位置決め保持されることで、従来技術のようにベルト伝達機構のようなベルトの張力調整が不要になるため、電動パワーステアリング装置内の駆動変換機構に対する回動伝達機構の組み付けが容易になる。 As shown in FIGS. 1 and 3, the pair of first pinion gears 8a of the drive gear mechanism 4 meshes with the first driven gear 9, and the second pinion gear 8b meshes with the second driven gear 10. Positioned and held by the clip 6. According to the electric power steering device 1 of the present embodiment, the transmission of the rotational torque between the electric motor (not shown) and the sliding screw mechanism 3 is the drive pinion gear 4a, the driven pinion gear 8, the first and second driven gears 9, A pair of driven pinion gears 8 which are performed by the 10 and the clutch 11 and mesh with the first and second driven gears 9 and 10 are easily positioned and held by the clip 6, so that a belt such as a belt transmission mechanism as in the prior art is used. Since it is not necessary to adjust the tension of the above, it becomes easy to assemble the rotation transmission mechanism to the drive conversion mechanism in the electric power steering device.
　また、すべりねじ機構３は、外周に雄ねじ部１５ａを備えたラック軸１５と、すべりナット機構１６を有する。すべりナット機構１６は、すべりナット１７と、シリンダー１８によって構成される。すべりナット１７は、内側に雄ねじ部１５ａに噛み合う雌ねじ部１７ａを有し、かつ外周にヘリカルスプライン１７ｂを有する。シリンダー１８は、ヘリカルスプライン１７ｂに噛み合うヘリカルスプライン１８ａを内側に有し、かつシリンダーの中心軸線Ｌ０方向に延びるように多数形成され、かつクラッチ１１の多数のスライド溝１１ｆに係合するスライド溝１８ｂを外周に有する。シリンダー１８は、多数のスライド溝１８ｂをスライド溝１１ｆに係合させた状態でクラッチ１１の内側に挿入され、クラッチ１１を中心軸線Ｌ０に沿った方向にスライド可能に保持する。クラッチ１１は、フランジ部１１ｅの溝部１１ｄに係合する電動アクチュエータアーム（図示しない進退機構）によって前後に押圧されることで、シリンダーに対して前後にスライドする。尚、図示しない進退機構は、クラッチ１１に設けられたソレノイド機構等で実現されても良い。 Further, the sliding screw mechanism 3 has a rack shaft 15 having a male screw portion 15a on the outer periphery and a sliding nut mechanism 16. The sliding nut mechanism 16 is composed of a sliding nut 17 and a cylinder 18. The sliding nut 17 has a female threaded portion 17a that meshes with the male threaded portion 15a on the inside, and has a helical spline 17b on the outer periphery. The cylinder 18 has a large number of helical splines 18a that mesh with the helical splines 17b inside, is formed so as to extend in the direction of the central axis L0 of the cylinder, and has a large number of slide grooves 18b that engage with a large number of slide grooves 11f of the clutch 11. It has on the outer circumference. The cylinder 18 is inserted inside the clutch 11 with a large number of slide grooves 18b engaged with the slide grooves 11f, and holds the clutch 11 slidably in the direction along the central axis L0. The clutch 11 slides back and forth with respect to the cylinder by being pressed back and forth by an electric actuator arm (advancing and retreating mechanism (not shown)) that engages with the groove portion 11d of the flange portion 11e. The advance / retreat mechanism (not shown) may be realized by a solenoid mechanism or the like provided on the clutch 11.
　尚、すべりナット機構１６においては、ヘリカルスプライン１７ｂの替わりに摩擦角を超えるリード角を持つ雄ねじをすべりナット１７の外周に形成し、ヘリカルスプライン１８ａの替わりに摩擦角を超えるリード角を持つ雌ねじをシリンダー１８の内側に形成し、摩擦角を超えるリード角を持つ前記雄ねじ及び雌ねじを介してすべりナット１７をシリンダー１８に噛み合わせても良い。 In the sliding nut mechanism 16, a male screw having a lead angle exceeding the friction angle is formed on the outer periphery of the sliding nut 17 instead of the helical spline 17b, and a female screw having a lead angle exceeding the friction angle is formed instead of the helical spline 18a. The slip nut 17 may be engaged with the cylinder 18 via the male screw and the female screw formed inside the cylinder 18 and having a lead angle exceeding the friction angle.
　また、図２に示すようにラック軸１５に螺着されるすべりナット１７の前後には、コイルバネである第１圧縮ばね１９及び第２圧縮ばね２０がそれぞれ配置され、更にその前後には、第１ワッシャ２１及び第２ワッシャ２２がそれぞれ配置される。図２に示すラック軸１５は、すべりナット１７を螺着され、第１圧縮ばね１９、第２圧縮ばね２０、第１ワッシャ２１及び第２ワッシャ２２を配置された状態でシリンダー１８に螺着され、かつシリンダー１８と共に第１従動歯車９、第２従動歯車１０を保持したクラッチ１１に挿入される。 Further, as shown in FIG. 2, a first compression spring 19 and a second compression spring 20, which are coil springs, are arranged before and after the sliding nut 17 screwed to the rack shaft 15, and further, before and after the first compression spring 19 and a second compression spring 20. The 1 washer 21 and the 2nd washer 22 are arranged respectively. The rack shaft 15 shown in FIG. 2 is screwed with a sliding nut 17, and is screwed to the cylinder 18 with the first compression spring 19, the second compression spring 20, the first washer 21, and the second washer 22 arranged. And, it is inserted into the clutch 11 holding the first driven gear 9 and the second driven gear 10 together with the cylinder 18.
　図３に示すように、シリンダー１８の前方と第２従動歯車１０の後方に両端が突出したラック軸１５は、前後を第１軸受である第１軸受部材２３及び第２軸受である第２軸受部材２４によって保持され、かつ第１球軸受２５及び第２球軸受２６を介してハウジング（図示せず）に取り付けられる。 As shown in FIG. 3, the rack shaft 15 having both ends protruding in front of the cylinder 18 and rear of the second driven gear 10 has a first bearing member 23 which is a first bearing and a second bearing which is a second bearing in the front and rear. It is held by a member 24 and attached to a housing (not shown) via a first ball bearing 25 and a second ball bearing 26.
　図３に示す、第１軸受部材２３は、円筒状に形成されて、先端外周にベアリング固定部２３ａを有し、その基端部に第１球軸受２５を後方に向けて位置決めするフランジ部２３ｂを有し、ベアリング固定部２３ａの内側に円筒状のラック軸保持部２３ｃを有し、フランジ部２３ｂの内側に底部２３ｄを有し、底部の基端側に第１ワッシャ２１を係合させる円形溝２３ｅを有する。第２軸受部材２４は、円筒状に形成されて、基端外周にベアリング固定部２４ａを有し、その先端部に第２球軸受２６を前方に向けて位置決めするフランジ部２４ｂを有し、ベアリング固定部２４ａの内側に円筒状のラック軸保持部２４ｃを有し、フランジ部２４ｂの内側に底部２４ｄを有し、底部の先端側に第２ワッシャ２２を係合させる円形溝２４ｅを有する。 The first bearing member 23 shown in FIG. 3 is formed in a cylindrical shape, has a bearing fixing portion 23a on the outer periphery of the tip, and has a flange portion 23b for positioning the first ball bearing 25 rearward at the base end portion thereof. The circular rack shaft holding portion 23c is provided inside the bearing fixing portion 23a, the bottom portion 23d is provided inside the flange portion 23b, and the first washer 21 is engaged with the base end side of the bottom portion. It has a groove 23e. The second bearing member 24 is formed in a cylindrical shape, has a bearing fixing portion 24a on the outer periphery of the base end, and has a flange portion 24b at the tip portion thereof for positioning the second ball bearing 26 forward. A cylindrical rack shaft holding portion 24c is provided inside the fixing portion 24a, a bottom portion 24d is provided inside the flange portion 24b, and a circular groove 24e for engaging the second washer 22 is provided on the tip end side of the bottom portion.
　図２と図３に示すラック軸１５は、前後を第１及び第２軸受部材２３，２４のラック軸保持部２３ｃ、２４ｃにそれぞれ挿通され、シリンダー１８は、円形溝２３ｅ及び２４ｅに保持された第１及び第２ワッシャ２１，２２により先端及び基端を挟持される。その状態で第１及び第２軸受部材２３，２４は、第１球軸受２５，２６を介してハウジング（図示せず）に取り付けられることにより、ラック軸１５と共にハウジング（図示せず）に回動可能に保持される。また、シリンダー１８に対してスライド可能に保持されるクラッチ１１は、前方へのスライド時にフランジ部１１ｅの下に形成されたストッパ１１ｇとシリンダー１８の先端近傍に形成されたフランジ部１８ｃとが当接することで前方に位置決めされ、更に後方へのスライド時に基端部１１ｈが第２軸受部材２４の先端部２４ｆと当接することで後方に位置決めされる。 The rack shafts 15 shown in FIGS. 2 and 3 were inserted into the rack shaft holding portions 23c and 24c of the first and second bearing members 23 and 24, respectively, and the cylinder 18 was held by the circular grooves 23e and 24e. The tip and base ends are sandwiched by the first and second washers 21 and 22. In that state, the first and second bearing members 23 and 24 rotate to the housing (not shown) together with the rack shaft 15 by being attached to the housing (not shown) via the first ball bearings 25 and 26. Can be retained. Further, in the clutch 11 slidably held with respect to the cylinder 18, the stopper 11g formed under the flange portion 11e and the flange portion 18c formed near the tip of the cylinder 18 come into contact with each other when sliding forward. As a result, it is positioned forward, and when it slides backward, the base end portion 11h comes into contact with the tip portion 24f of the second bearing member 24 and is positioned rearward.
　その際、図２に示す第１圧縮ばね１９は、第１ワッシャ２１とすべりナット１７の前端部に圧縮されることによって、すべりナット１７を第２軸受部材２４に向けて付勢し、かつ第２圧縮ばね２０は、すべりナット１７の後端部と第２ワッシャ２２に圧縮されることによって、すべりナット１７を第１圧縮ばね１９と同じ付勢力で第１軸受部材２３に向けて付勢し、すべりナット１７が、両圧縮ばねの付勢力の釣り合いによってラック軸１５の中央部に保持される。 At that time, the first compression spring 19 shown in FIG. 2 is compressed to the front end portion of the first washer 21 and the sliding nut 17 to urge the sliding nut 17 toward the second bearing member 24 and to urge the sliding nut 17 to the second bearing member 24. The two compression springs 20 are compressed by the rear end portion of the sliding nut 17 and the second washer 22 to urge the sliding nut 17 toward the first bearing member 23 with the same urging force as the first compression spring 19. The sliding nut 17 is held at the center of the rack shaft 15 by the balance of the urging forces of both compression springs.
　図１から図３によって、本実施例の電動パワーステアリング装置１の動作を説明する。図１に示すラック軸１５は、図示しないステアリングによってドライバーが車両を左右に操舵することに伴って前後に進退する。図示しない電動モータは、ステアリング操舵に基づくラック軸１５の進退方向に併せて駆動ピニオンギヤ４ａを回動させ、従動ピニオンギヤ８を介して第１従動歯車９及び第２従動歯車１０の双方を同時に回動させる。 The operation of the electric power steering device 1 of this embodiment will be described with reference to FIGS. 1 to 3. The rack shaft 15 shown in FIG. 1 moves back and forth as the driver steers the vehicle left and right by steering (not shown). An electric motor (not shown) rotates the drive pinion gear 4a in accordance with the advancing / retreating direction of the rack shaft 15 based on steering, and simultaneously rotates both the first driven gear 9 and the second driven gear 10 via the driven pinion gear 8. Let me.
　図１及び図３に示すクラッチ１１は、第３ドッグ１１ｂ及び第４ドッグ１１ｃが第１従動歯車９の第１ドッグ９ｂ及び第２従動歯車１０の第２ドッグ１０ｂのいずれにも噛み合わず、第１及び第２従動歯車９，１０のいずれからも回動トルクを受けない「自由配置」に配置されている。クラッチ１１が、図示しない電動アクチュエータアームによって後方にスライドし、第３ドッグ１１ｂが第１従動歯車９の第１ドッグ９ｂに噛み合う「第１配置」に配置されると、クラッチ１１は、図示しない電動モータの回動に伴って第１従動歯車９から大きなトルクを受け、低速で回動する。 In the clutch 11 shown in FIGS. 1 and 3, the third dog 11b and the fourth dog 11c do not mesh with any of the first dog 9b of the first driven gear 9 and the second dog 10b of the second driven gear 10, and the first It is arranged in a "free arrangement" that does not receive rotational torque from any of the 1st and 2nd driven gears 9 and 10. When the clutch 11 is slid rearward by an electric actuator arm (not shown) and the third dog 11b is arranged in the "first arrangement" in which the first dog 9b of the first driven gear 9 is engaged, the clutch 11 is electrically operated (not shown). As the motor rotates, it receives a large torque from the first driven gear 9 and rotates at a low speed.
　また、図１及び図３に示すクラッチ１１が、図示しない電動アクチュエータアームによって前方にスライドし、第４ドッグ１１ｃが第２従動歯車１０の第２ドッグ１０ｂに噛み合う「第２配置」に配置されると、クラッチ１１は、図示しない電動モータの回動に伴って第２従動歯車１０から第１従動歯車９よりも小さなトルクを受けて、高速で回動する。クラッチ１１は、図示しない車速検出装置によって検知された車速に伴い、例えば時速０ｋｍ～１０ｋｍ等の低速時に電動アクチュエータ機構によって自動的に第１配置に配置され、時速１０ｋｍを越えたときに第２配置に自動的に切り換えられるようにすることが望ましい。 Further, the clutch 11 shown in FIGS. 1 and 3 is slid forward by an electric actuator arm (not shown), and the fourth dog 11c is arranged in the "second arrangement" in which the second dog 10b of the second driven gear 10 meshes with the second dog 10b. The clutch 11 receives a torque smaller than that of the first driven gear 9 from the second driven gear 10 as the electric motor (not shown) rotates, and rotates at a high speed. The clutch 11 is automatically arranged in the first arrangement by the electric actuator mechanism at a low speed such as 0 km to 10 km / h according to the vehicle speed detected by the vehicle speed detection device (not shown), and the second arrangement when the speed exceeds 10 km / h. It is desirable to be able to switch automatically to.
　図１及び図３に示すクラッチ１１は、図示しない電動モータの回動と「第１配置」または「第２配置」の選択的な配置に基づき、スライド溝１１ｆを介して内側に噛み合っているシリンダー１８を回動させる。その際、ヘリカルスプライン１８ａ（あるいは摩擦角を超えるリード角を持つ雌ねじ）とヘリカルスプライン１７ｂ（あるいは摩擦角を超えるリード角を持つ雄ねじ）を介してシリンダー１８に噛み合うすべりナット１７は、シリンダー１８に対して相対回動しつつ中心軸線Ｌ０に沿って前後に進退する。更にすべりナット１７は、前後に進退しつつ回動することにより、雌ねじ１７ａと雄ねじ１５ａを介して噛み合うラック軸１５を前後に進退させることによって、ラック軸１５に中心軸線Ｌ０に沿った方向の軸力を付与する。本実施例の電動パワーステアリング装置は、停止中の車両や低速走行時のステアリング操舵において、クラッチ１１が「第１配置」に配置されることで、ラック軸１５に大きな軸力を低速で発生させてステアリング操舵を補助し、「第２配置」に配置されることで、ラック軸１５に「第１配置」よりも小さな軸力を高速で発生させてステアリング操舵を補助する。 The clutch 11 shown in FIGS. 1 and 3 is a cylinder that meshes inward through a slide groove 11f based on the rotation of an electric motor (not shown) and the selective arrangement of the "first arrangement" or the "second arrangement". 18 is rotated. At that time, the sliding nut 17 that meshes with the cylinder 18 via the helical spline 18a (or a female screw having a lead angle exceeding the friction angle) and the helical spline 17b (or a male screw having a lead angle exceeding the friction angle) is attached to the cylinder 18. While rotating relative to each other, it moves back and forth along the central axis L0. Further, the sliding nut 17 rotates while advancing and retreating back and forth to advance and retreat the rack shaft 15 that meshes with the female screw 17a and the male screw 15a, thereby moving the rack shaft 15 back and forth along the central axis L0. Give power. In the electric power steering device of this embodiment, a large axial force is generated on the rack shaft 15 at a low speed by arranging the clutch 11 in the "first arrangement" in steering steering of a stopped vehicle or running at a low speed. By assisting the steering and steering and arranging in the "second arrangement", the rack shaft 15 is generated with an axial force smaller than that in the "first arrangement" at a high speed to assist the steering.
　本実施例の電動パワーステアリング装置１によれば、すべりナット１７とシリンダー１８との間に生じる摩擦力より推力が勝り、噛み合いに利用するねじをヘリカルスプラインあるいは摩擦角を超えるリード角を持つねじとすることですべりナット１７がシリンダー１８に対して回動し易くなり、ラック軸１５を進退させやすくなるため、電圧の低いバッテリーで電動モータを作動させても、十分な推力をラック軸に与えることが出来る。また、ラック軸１５に付与される軸力の大きさは、図示しない電動モータの駆動軸に発生させるトルクそのものを大きくしなくても、ドッグクラッチ１１によって切り替えることが出来るため、現行の２４Ｖのような電圧の低いバッテリーを積んだ車重の大きな大型車への搭載が可能になる。 According to the electric power steering device 1 of the present embodiment, the thrust is superior to the frictional force generated between the sliding nut 17 and the cylinder 18, and the screw used for meshing is a helical spline or a screw having a lead angle exceeding the frictional angle. This makes it easier for the sliding nut 17 to rotate with respect to the cylinder 18, and makes it easier for the rack shaft 15 to move forward and backward. Therefore, even if the electric motor is operated with a battery with a low voltage, sufficient thrust is given to the rack shaft. Can be done. Further, the magnitude of the axial force applied to the rack shaft 15 can be switched by the dog clutch 11 without increasing the torque itself generated in the drive shaft of the electric motor (not shown), as in the current 24V. It can be installed in a large vehicle with a heavy vehicle weight loaded with a low-voltage battery.
　一方で、図示しない車両のドライバーがステアリング操舵を終了してステアリングから手を離すと、図１及び図３のラック軸は、図示しない操舵車輪のキャスター角とトレール量の設定に基づいて操舵車輪が直進方向に戻る際に、操舵車輪側からステアリング操舵時と逆向きの軸力を受ける。ラック軸１５に操舵車輪からの軸力が作用すると、すべりナット１７は、ヘリカルスプライン１７ｂ（あるいは摩擦角を超えるリード角を持つ雄ねじ）とシリンダー１８のヘリカルスプライン１８ａ（あるいは摩擦角を超えるリード角を持つ雌ねじ）において発生する摩擦の低さにより、自立することなくラック軸１５及びシリンダー１８に対して相対回動し、ラック軸１５を中心軸線Ｌ０に沿ってステアリング操舵時と逆向きに進退動作させ、操舵車輪を直進方向に戻す。 On the other hand, when the driver of a vehicle (not shown) finishes steering and releases the steering wheel, the rack shafts of FIGS. 1 and 3 have the steering wheels based on the setting of the caster angle and the trail amount of the steering wheels (not shown). When returning to the straight direction, the steering wheel side receives an axial force in the opposite direction to that during steering. When an axial force from the steering wheel acts on the rack shaft 15, the sliding nut 17 has a helical spline 17b (or a male screw having a lead angle exceeding the friction angle) and a helical spline 18a (or a lead angle exceeding the friction angle) of the cylinder 18. Due to the low friction generated in the female screw), the rack shaft 15 rotates relative to the rack shaft 15 and the cylinder 18 without becoming independent, and the rack shaft 15 is moved forward and backward along the central axis L0 in the direction opposite to that during steering. , Return the steering wheel to the straight direction.
　また、図示しない車両のドライバーがステアリング操舵方向を左方から右方へ、または右方から左方に切り換えた場合、電動モータが停止してクラッチ１１に有効な反転トルクを発生させるまでに一瞬のタイムラグが生じることで、ラック軸１５には、図示しない電動モータから付与される軸力の補助に一瞬の低下が生じる。 Further, when the driver of a vehicle (not shown) switches the steering steering direction from left to right or from right to left, it takes a moment until the electric motor stops and the clutch 11 generates an effective reversing torque. Due to the time lag, the rack shaft 15 has a momentary decrease in the auxiliary of the axial force applied by the electric motor (not shown).
　しかし、ステアリングの左右いずれかの操舵時に、ラック軸１５の中央位置から左右いずれかの偏った位置に配置されたすべりナット１７が、第１圧縮ばね１９と第２圧縮ばね２０のうち一方を圧縮しているため、本実施例の電動パワーステアリング装置によれば、ドライバーがステアリング操舵方向を切り換えると、圧縮されていた第１圧縮ばね１９あるいは第２圧縮ばね２０が、元に戻ろうとする力によって、すべりナット１７に反転方向（電動モーターの反転方向）のトルクを与えることにより、図示しない電動モータからラック軸１５に付与される軸力の低下が、すべりナット１７に作用する第１圧縮ばね１９あるいは第２圧縮ばね２０の付勢力に基づいてラック軸１５に発生する軸力によって補われる。従って、本実施例の電動パワーステアリング装置によれば、操舵方向の反転時においてラック軸１５に軸力の補助の寸断が発生しない。 However, when steering either the left or right side of the steering wheel, the sliding nut 17 arranged at a position deviated from the center position of the rack shaft 15 to the left or right side compresses one of the first compression spring 19 and the second compression spring 20. Therefore, according to the electric power steering device of the present embodiment, when the driver switches the steering steering direction, the compressed first compression spring 19 or the second compression spring 20 is driven by a force that tries to return to the original position. By applying torque in the reversing direction (reversing direction of the electric motor) to the sliding nut 17, a decrease in the axial force applied to the rack shaft 15 from the electric motor (not shown) acts on the sliding nut 17. Alternatively, it is supplemented by the axial force generated in the rack shaft 15 based on the urging force of the second compression spring 20. Therefore, according to the electric power steering device of the present embodiment, the rack shaft 15 does not break the auxiliary force when the steering direction is reversed.
１　　　　　　　電動パワーステアリング装置
２　　　　　　　回動伝達機構
３　　　　　　　すべりねじ機構（動力変換機構）
４　　　　　　　駆動歯車機構
４ａ　　　　　　駆動ピニオンギヤ
４ｃ　　　　　　アイドラーギヤ
５　　　　　　　従動歯車機構
６　　　　　　　クリップ
８　　　　　　　従動ピニオンギヤ
８ａ　　　　　　第１ピニオンギヤ
８ｂ　　　　　　第２ピニオンギヤ
９　　　　　　　第１従動歯車
１０　　　　　　第２従動歯車
１１　　　　　　クラッチ
１５　　　　　　ラック軸
１５ａ　　　　　雄ねじ部
１６　　　　　　すべりナット機構
１７　　　　　　すべりナット
１７ａ　　　　　雌ねじ部
１７ｂ　　　　　ヘリカルスプライン
１８　　　　　　シリンダー
１８ａ　　　　　ヘリカルスプライン
１９　　　　　　第１圧縮ばね
２０　　　　　　第２圧縮ばね
２３　　　　　　第１軸受部材（第１軸受）
２４　　　　　　第２軸受部材（第２軸受）
  1 Electric power steering device 2 Rotation transmission mechanism 3 Sliding screw mechanism (power conversion mechanism)
4 Drive gear mechanism 4a Drive pinion gear 4c Idler gear 5 Driven gear mechanism 6 Clip 8 Driven pinion gear 8a 1st pinion gear 8b 2nd pinion gear 9 1st driven gear 10 2nd driven gear 11 Clutch 15 Rack shaft 15a Male thread 16 Sliding nut mechanism 17 Sliding nut 17a Female thread 17b Helical spline 18 Cylinder 18a Helical spline 19 1st compression spring 20 2nd compression spring 23 1st bearing member (1st bearing)
24 Second bearing member (second bearing)

Claims (5)

  1. 　電動モータの回動を伝達してナット機構を回動させる回動伝達機構と、ナット機構の回動運動をラック軸の往復直進運動に変換してステアリング操作に伴うラック軸の直線運動を補助する動力変換機構と、を備えた電動パワーステアリング装置において、
    　前記回動伝達機構は、
    　電動モータによって回動する駆動ピニオンギヤと、同軸かつ一体に形成された第１ピニオンギヤ及び第２ピニオンギヤを有し、前記駆動ピニオンギヤによって回動する一対の従動ピニオンギヤを有する駆動歯車機構と、
    　駆動歯車機構から回動トルクを受けてナット機構を回動させる従動歯車機構と、
    　前記一対の従動ピニオンギヤを互いに離間した状態に位置決め保持するクリップと、
    　を有することを特徴とする電動パワーステアリング装置。     A rotation transmission mechanism that transmits the rotation of the electric motor to rotate the nut mechanism, and a rotation transmission mechanism that converts the rotational movement of the nut mechanism into a reciprocating linear motion of the rack shaft to assist the linear motion of the rack shaft accompanying the steering operation. In an electric power steering device equipped with a power conversion mechanism
    The rotation transmission mechanism is
    A drive gear mechanism having a drive pinion gear rotated by an electric motor, a first pinion gear and a second pinion gear coaxially and integrally formed, and a pair of driven pinion gears rotated by the drive pinion gear.
    A driven gear mechanism that rotates the nut mechanism by receiving rotational torque from the drive gear mechanism,
    A clip that positions and holds the pair of driven pinion gears in a state of being separated from each other,
    An electric power steering device characterized by having.
  2. 　前記従動歯車機構は、
    　前記第１ピニオンギヤに噛み合う低速回動用の第１従動歯車と、
    　前記第２ピニオンギヤに噛み合う高速回動用の第２従動歯車と、
    　第１従動歯車または第２従動歯車の回動を前記シリンダーに選択的に伝達するクラッチと、
    　を有することを特徴とする請求項１に記載の電動パワーステアリング装置。     The driven gear mechanism
    A first driven gear for low-speed rotation that meshes with the first pinion gear,
    A second driven gear for high-speed rotation that meshes with the second pinion gear,
    A clutch that selectively transmits the rotation of the first driven gear or the second driven gear to the cylinder,
    The electric power steering device according to claim 1, wherein the electric power steering device is provided.
  3. 　前記動力変換機構は、
    　外周に雄ねじ部を備えた前記ラック軸と、前記ラック軸の外周に回動可能に螺着されたすべりナット機構と、を有するすべりねじ機構であることを特徴とする、請求項１または２に記載の電動パワーステアリング装置。     The power conversion mechanism
    The first or second aspect of the present invention, wherein the rack shaft has a male screw portion on the outer periphery thereof and a slip nut mechanism rotatably screwed to the outer circumference of the rack shaft. The electric power steering device described.
  4. 　前記すべりナット機構は、
    　内周にヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雌ねじを形成されると共に前記回動伝達機構によって回動するシリンダーと、
    　前記ラック軸の外周に螺着され、更に外周に形成されたヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雄ねじを介してシリンダーのヘリカルスプラインあるいは摩擦角を超えるリード角を持つ雌ねじに螺着されたすべりナットと、を有することを特徴とする請求項３に記載の電動パワーステアリング装置。     The sliding nut mechanism is
    A cylinder having a helical spline or a female screw having a lead angle exceeding the friction angle formed on the inner circumference and rotating by the rotation transmission mechanism.
    It was screwed to the outer circumference of the rack shaft, and further screwed to the helical spline of the cylinder or the female screw having a lead angle exceeding the friction angle via a helical spline formed on the outer circumference or a male screw having a lead angle exceeding the friction angle. The electric power steering device according to claim 3, further comprising a sliding nut.
  5. 　前記ラック軸は、第１軸受と第２軸受によって支持され、
    　前記すべりナットは、前記一対の第１軸受と第２軸受の間に配置され、
    　第１軸受に接触すると共にすべりナットを第２軸受に向けて付勢する第１圧縮ばねと、第２軸受に接触すると共にすべりナットを第１軸受に向けて付勢する第２圧縮ばねと、有することを特徴とする請求項４に記載の電動パワーステアリング装置。     The rack shaft is supported by a first bearing and a second bearing.
    The sliding nut is arranged between the pair of first bearings and the second bearing.
    A first compression spring that contacts the first bearing and urges the sliding nut toward the second bearing, and a second compression spring that contacts the second bearing and urges the sliding nut toward the first bearing. The electric power steering device according to claim 4, wherein the electric power steering device is provided.
PCT/JP2019/029775 2019-07-30 2019-07-30 Electric power steering device WO2021019670A1 (en)

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JP2001206233A (en) * 1999-12-21 2001-07-31 Ford Global Technol Inc Steering system for automobile having actuator shaft to be linearly driven
JP3653617B2 (en) * 1997-02-28 2005-06-02 光洋精工株式会社 Power steering device
JP2006329258A (en) * 2005-05-24 2006-12-07 Hitachi Ltd Rotation-linear motion converting mechanism
JP2008273327A (en) * 2007-04-26 2008-11-13 Nissan Motor Co Ltd Variable gear ratio steering device for vehicle
JP2014202354A (en) * 2013-04-10 2014-10-27 Thk株式会社 Feeder
KR20150078303A (en) * 2013-12-30 2015-07-08 창원대학교 산학협력단 Series elastic actuator device
JP2015166223A (en) * 2014-03-04 2015-09-24 Ntn株式会社 Vehicular steering device
US9470296B1 (en) * 2015-04-17 2016-10-18 Trw Automotive U.S. Llc Anti-lash assembly for vehicle power steering

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08338482A (en) * 1995-06-13 1996-12-24 Exedy Corp Transmission
JP3653617B2 (en) * 1997-02-28 2005-06-02 光洋精工株式会社 Power steering device
JP2001206233A (en) * 1999-12-21 2001-07-31 Ford Global Technol Inc Steering system for automobile having actuator shaft to be linearly driven
JP2006329258A (en) * 2005-05-24 2006-12-07 Hitachi Ltd Rotation-linear motion converting mechanism
JP2008273327A (en) * 2007-04-26 2008-11-13 Nissan Motor Co Ltd Variable gear ratio steering device for vehicle
JP2014202354A (en) * 2013-04-10 2014-10-27 Thk株式会社 Feeder
KR20150078303A (en) * 2013-12-30 2015-07-08 창원대학교 산학협력단 Series elastic actuator device
JP2015166223A (en) * 2014-03-04 2015-09-24 Ntn株式会社 Vehicular steering device
US9470296B1 (en) * 2015-04-17 2016-10-18 Trw Automotive U.S. Llc Anti-lash assembly for vehicle power steering

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