JP2005145436A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device which absorbs impact energy with the rotor of an electric motor for auxiliary steering and a frame. <P>SOLUTION: The electric power steering device comprises an input shaft 1 connected to steering wheels A, an electric motor 2 for an auxiliary steering arranged coaxially with the input shaft 1, and an output shaft 3 to which the rotation force of the electric motor 2 is transmitted. The electric motor 2 is constituted of a rotor 21 having a first recessed part 21a and a second recessed part 21b for absorbing impact energy, which allow the input shaft 1 and the output shaft 3 to be movably fitted therein by the impact energy, and of a frame 22 plastically deformed in the axial direction of the input shaft 1 and the output shaft 3 by the impact energy applied to the shafts 1, 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric power steering apparatus that assists steering by rotation of an electric motor for assisting steering.

  The electric power steering apparatus is an indirect transmission type (including a speed reduction mechanism that increases the rotational force of the electric motor and transmits the torque to the steering shaft. For example, refer to Patent Document 1), and an electric motor for assisting steering is arranged coaxially with the steering shaft, and is configured to transmit the rotational force of the electric motor directly from the rotor of the electric motor to the steering shaft. The direct transmission type (see, for example, Patent Document 2) is known.

  Since the vehicle equipped with the electric power steering apparatus configured as described above has a layout in which almost the entire electric power steering apparatus is arranged in the vehicle interior, the total length of the electric power steering apparatus is inevitably determined. .

By the way, the indirect power transmission type electric power steering device has a configuration in which a part of the speed reduction mechanism is provided in the middle of the steering shaft and the electric motor is arranged at a position deviated from the steering shaft. An impact energy absorption mechanism capable of absorbing the impact energy of the secondary collision applied to the steering shaft from the member can be provided in the middle of the steering shaft, or can be provided in the cylindrical housing that supports the steering shaft. Impact energy can be absorbed relatively easily while relatively moving the shaft and / or the housing in the axial direction.
JP 2001-10512 A Japanese Patent No. 2539631

  However, in the direct power transmission type electric power steering device, the electric motor is coaxially arranged in the middle of the steering shaft, so that it is within the entire length of the electric power steering device that is inevitably determined, and the position excluding the electric motor portion. It is difficult to provide the impact energy absorbing mechanism. In addition, since the direct transmission type electric motor generates a relatively large torque, the size of the electric motor becomes relatively large, and the length of the portion where the impact energy absorbing mechanism is provided is shortened. It becomes even more difficult to provide a mechanism.

  In addition, since the size of the electric motor is large, there is a problem that it is difficult to provide a telescopic mechanism. Further, when a telescopic mechanism is provided, when performing telescopic adjustment, the lower end of the steering shaft is connected by a universal shaft joint. As a result, the angle of the transmission shaft to the steering shaft changes, and the steering torque applied to the steering shaft changes.

  The present invention has been made in view of such circumstances, and a main purpose thereof is to absorb impact energy by a rotor and a frame of an electric motor for assisting steering, and when a telescopic adjustment is performed, a steering torque is reduced. An object of the present invention is to provide an electric power steering device that can prevent the change.

  An electric power steering device according to a first aspect of the invention is an electric power steering device configured to assist steering by rotation of an electric motor for assisting steering disposed coaxially with a steering shaft that rotates in response to an operation of a steering member. The electric motor includes a rotor having a shock energy absorbing hole fitted therein so that the steering shaft can be moved by impact energy applied to the steering shaft.

  An electric power steering apparatus according to a second aspect of the invention is an electric power steering apparatus configured to assist steering by rotation of an electric motor for assisting steering disposed coaxially with a steering shaft that rotates in response to an operation of a steering member. The electric motor supports a rotor connected to the steering shaft, a stator disposed around the rotor, and supports the stator, and can be deformed in an axial direction of the steering shaft by impact energy applied to the steering shaft. It is characterized by comprising a frame.

  According to a third aspect of the present invention, there is provided the electric power steering apparatus according to the first aspect, wherein the steering shaft includes an input shaft connected to the steering member, and an output shaft through which the rotational force of the input shaft is transmitted via the rotor. And at least one of the input shaft and the output shaft is fitted into the impact energy absorbing hole.

  An electric power steering apparatus according to a fourth invention is the electric power steering device according to the third invention, wherein the electric motor supports a stator disposed around the rotor, and impact energy applied to at least one of the input shaft and the output shaft. And a frame that can be deformed in the axial direction of the steering shaft.

  An electric power steering apparatus according to a fifth aspect of the present invention is the electric power steering apparatus according to the first aspect, wherein the steering shaft has an input shaft connected to the steering member, and an output shaft through which the rotational force of the input shaft is transmitted via the rotor. The input shaft has a first shaft connected to the steering member, and a second shaft connected to the first shaft by a torsion bar and fitted in the impact energy absorbing hole. It is characterized by.

  According to a sixth aspect of the present invention, there is provided an electric power steering apparatus that assists steering by rotation of an electric motor for assisting steering having a rotor arranged coaxially with a steering shaft that rotates in response to an operation of a steering member. In the apparatus, the steering shaft has an input shaft connected to the steering member, and an output shaft to which a rotational force of the input shaft is transmitted through the rotor, and the rotor is fitted with the output shaft, It has a fitting hole that allows the electric motor to move to the axis with respect to the output shaft.

  According to the first invention, since the rotor of the electric motor has the impact energy absorbing hole, and the steering shaft is fitted in the impact energy absorbing hole, the impact applied to the steering shaft due to a vehicle collision or the like. Energy can be absorbed within the entire length of the electric power steering apparatus that is inevitably determined, and the load on the driver can be reduced. Moreover, since the impact energy can be absorbed by the rotor of the electric motor, the number of parts and the number of assembling steps can be reduced as compared with the steering shaft and the housing supporting the steering shaft provided with the impact energy absorbing mechanism. it can.

  According to the second invention, since the frame of the electric motor is configured to absorb the impact energy, the impact energy can be absorbed within the entire length of the electric power steering apparatus that is inevitably determined, and is added to the driver. The load can be reduced. In addition, since the impact energy can be absorbed by the frame of the electric motor, the number of parts and the number of assembling steps can be reduced as compared with a steering shaft and a housing that supports the steering shaft provided with an impact energy absorption mechanism. it can.

  According to the third aspect of the present invention, the electric power steering apparatus inevitably determines the primary impact energy and the secondary impact energy applied to the steering shaft by adopting a configuration in which the input shaft and the output shaft are fitted in the impact energy absorbing hole. Can be absorbed within the entire length of the vehicle, and the load applied to the driver can be further reduced. In addition, since the primary impact energy and the secondary impact energy can be absorbed by the rotor of the electric motor, the number of parts and the assembly are compared with those in which the impact energy absorbing mechanism is provided on the steering shaft and the housing that supports the steering shaft. Man-hours can be reduced.

  In addition, by adopting a configuration in which the input shaft or the output shaft is fitted in the impact energy absorbing hole, the primary impact energy or the secondary impact energy applied to the steering shaft is absorbed within the entire length of the electric power steering apparatus. can do.

  According to the fourth aspect of the present invention, the impact energy applied to the steering shaft can be absorbed at the two locations of the rotor and the frame of the electric motor, so the impact energy absorption load at the rotor and the frame can be reduced, and the driver The load applied to can be further reduced.

  According to the fifth invention, since the second shaft body formed separately from the first shaft body is fitted into the impact energy absorbing hole, the impact energy absorbing force of the second shaft body and the impact energy absorbing hole is reduced. The change can be simplified by changing the second shaft body, and the first shaft body and the second shaft body can be relatively rotated via the torsion bar, so that the steering torque applied to the steering shaft can be easily detected. Is possible.

  According to the sixth invention, the rotor of the electric motor has the insertion hole, and the electric motor and the input shaft can be moved in the axial direction with respect to the output shaft inserted into the insertion hole. Can be moved in the axial direction to perform telescopic adjustment. In addition, when performing telescopic adjustment, the position of the output shaft can be maintained, so the angle of the transmission shaft connected to the output shaft via a universal shaft joint can be maintained and the steering torque can be maintained. Can be prevented and driver discomfort due to torque changes can be eliminated.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
Embodiment 1
FIG. 1 is an enlarged cross-sectional view showing the configuration of Embodiment 1 of an electric power steering apparatus according to the present invention.
The electric power steering apparatus includes an input shaft 1 whose upper end is connected to a steered wheel A as a steering member, and a rotor 21 in which a lower portion of the input shaft 1 is fitted, and is arranged coaxially with the input shaft 1. The steering assisting electric motor 2 and the upper part are fitted into the rotor 21, and the torque applied to the input shaft 1 and the output shaft 3 through which the rotational force of the input shaft 1 is transmitted via the rotor 21 are detected. The electric motor 2 is driven on the basis of the torque detected by the sensor 4. The input shaft 1 and the output shaft 3 constitute a steering shaft that rotates according to the operation of the steering wheel A.

  Concave and convex strips 1 a and 3 a such as splines and serrations are provided around the lower portion of the input shaft 1 and the upper portion of the output shaft 3. Further, a first restricting member 5 for restricting the movement of the input shaft 1 is fitted in the middle of the input shaft 1, and a second for restricting the movement of the output shaft 3 in the middle of the output shaft 3. The regulating member 6 is fitted on the outside.

  The restricting members 5 and 6 are made of an annular body such as an E-type retaining ring and a C-shaped retaining ring that are harder than the frame 22 of the electric motor 2, and the rotor of the output shaft 3 while the primary impact energy is not applied to the output shaft 3. The movement of the input shaft 1 with respect to the rotor 21 is restricted while no secondary impact energy is applied to the input shaft 1. The first restricting member 5 is broken after the secondary impact energy is applied to the input shaft 1 and the first wall portion 22a of the frame 22 is plastically deformed as will be described later, and the second restricting member 6 is output shaft. 3, the primary impact energy is applied, and the second wall portion 22b of the frame 22 is plastically deformed as will be described later, and then fractures.

  The electric motor 2 includes a cylindrical rotor 21 having a first recess 21a and a second recess 21b in the central axis portions at both ends, and a cylindrical stator 23 disposed around the rotor 21 so as to be relatively rotatable. The brushless type includes a substantially cylindrical frame 22 made of aluminum that supports the stator 23.

  A plurality of permanent magnets whose magnetic poles are alternately different from each other are provided on the outer peripheral portion of the rotor 21 so as to be spaced apart from each other in the circumferential direction. Are provided around the concave and convex strips 21c and 21d. The primary impact energy applied to the output shaft 3 is absorbed by the frictional resistance between the concave and convex strips 3a and 21d, and the secondary impact energy applied to the input shaft 1 is absorbed by the concave and convex strips 1a. , 21c can be absorbed by the frictional resistance. In addition, relative movement of the input shaft 1 and the output shaft 3 is allowed between the lower end of the input shaft 1 and the bottom surface of the first recess 21a and between the upper end of the output shaft 3 and the bottom surface of the second recess 21b. There is a space to do. The first recess 21a and the second recess 21b constitute an impact energy absorbing hole.

  The frame 22 is disposed on both sides of the rotor 21 and has disk-shaped first wall portion 22a and second wall portion 22b having through holes into which the input shaft 1 and the output shaft 3 are inserted, and a stator 23 therein. And a cylindrical peripheral wall portion 22c supported on the periphery, and is formed of aluminum that can be plastically deformed by impact energy applied to the input shaft 1 and the output shaft 3. A first annular groove 22d for absorbing secondary impact energy is provided on the outer peripheral portion of the first wall portion 22a, and a second annular groove 22e for absorbing primary impact energy is provided on the outer peripheral portion of the second wall portion 22b. The first wall 22a is plastically deformed in the axial direction of the input shaft 1 by the first annular groove 22d, and the second wall 22b is plastically deformed in the axial direction of the output shaft 3 by the second annular groove 22e. It has become. The frame 22 may be any material that can be plastically deformed by the impact energy, and the material is not specified.

  First and second pressing plates 9, which are made of a material harder than the frame 22 on both sides of the frame 22, and the outer rings of the first and second rolling bearings 7, 8 are fitted and fixed to the center of the frame 22, respectively. 10 is arranged, and the secondary impact energy applied to the input shaft 1 is transmitted to the first wall portion 22a through the first restricting member 5, the case 11 and the first pressing plate 9, which will be described later. The applied primary impact energy is transmitted to the second wall portion 22b through the second restricting member 6 and the second pressing plate 10. Further, a bowl-shaped case 11 in which the sensor 4 is accommodated is disposed between the first pressing plate 9 and the first restricting member 5, and the secondary impact energy applied to the input shaft 1 is restricted to the first restriction. The member 5 is transmitted to the first pressing plate 9 through the case 11. The case 11 is made of a harder material than the frame 22.

  The sensor 4 is provided on a rotating body 12 that is fitted and fixed in the middle of the input shaft 1. The sensor 4 includes a pressure sensor that contacts the case 11. The pressure detected by the pressure sensor is connected to the control unit. Is converted into torque.

  The electric power steering apparatus configured as described above is almost entirely disposed in the vehicle interior of the vehicle, and is attached to the vehicle body by appropriate attachment means. Further, the lower part of the output shaft 3 is interlocked and connected to the steering mechanism via a transmission means such as a universal joint. In the electric power steering apparatus, the input shaft 1 and the output shaft 3 are fitted in the first recess 21 a and the second recess 21 b of the rotor 21, respectively, and the rotational force of the electric motor 2 is transmitted from the rotor 21 to the output shaft. 3 is transmitted directly.

  FIG. 2 is an explanatory diagram showing a process of absorbing primary impact energy. When the primary impact energy is applied to the output shaft 3 due to a frontal collision of the vehicle or the like and the output shaft 3 is pressed in the axial direction, the primary impact energy is applied to the second regulating member 6, the second rolling bearing 8 and the second rolling bearing 8. It is transmitted to the second wall portion 22b of the frame 22 through the pressing plate 10, and the second wall portion 22b is plastically deformed from the second annular groove 22e portion (see FIG. 2A), and a part of the primary impact energy. Can be absorbed. When the amount of plastic deformation of the second wall portion 22b decreases and plastic deformation becomes difficult, the second restricting member 6 is broken by the primary impact energy applied to the output shaft 3, and the second pressing of the output shaft 3 is performed. The movement restriction on the plate 10 is released, and the output shaft 3 moves relative to the rotor 21 in the second recess 21b (see FIG. 2B), so that a part of the primary impact energy can be absorbed. As described above, the primary impact energy can be absorbed stepwise by the frame 22 and the rotor 21, so that the impact energy absorption load at the rotor 21 and the frame 22 can be reduced.

  FIG. 3 is an explanatory diagram showing a process of absorbing secondary impact energy. When secondary impact energy is applied to the steered wheel A from the driver and the input shaft 1 connected to the steered wheel A is pressed in the axial direction, the secondary impact energy is applied to the first regulating member 5, the case 11, and the first rolling. It is transmitted to the first wall portion 22a of the frame 22 through the bearing 7 and the first pressing plate 9, and the first wall portion 22a is plastically deformed from the first annular groove 22d portion (see FIG. 3A). Part of the secondary impact energy can be absorbed. When the amount of plastic deformation of the first wall portion 22a decreases and plastic deformation becomes difficult, the first restricting member 5 is broken by the secondary impact energy applied to the input shaft 1, and the input shaft 1 with respect to the case 11 is broken. The movement restriction is released, and the input shaft 1 moves with respect to the rotor 21 in the first recess 21a (see FIG. 3B), so that a part of the secondary impact energy can be absorbed. Since the secondary impact energy can be absorbed stepwise by the frame 22 and the rotor 21 in this way, the impact energy absorption load at the rotor 21 and the frame 22 can be reduced.

  In the electric power steering apparatus configured as described above, the input shaft 1 and the output shaft 3 are fitted in the first recess 21a and the second recess 21b of the rotor 21, respectively, and a torsion for detecting steering torque. Since no bar is used, the total length of the electric power steering apparatus can be shortened compared to an electric power steering apparatus having a torsion bar, and the impact energy absorption stroke can be increased by this shortening.

Embodiment 2
FIG. 4 is an enlarged cross-sectional view showing the configuration of the second embodiment of the electric power steering apparatus. The electric power steering apparatus of the second embodiment eliminates the absorption of impact energy by the frame 22, and can absorb the secondary impact energy by the first recess 21a of the rotor 21 in which the input shaft 1 is movably fitted. The first and second regulating members 5, 6 of the first embodiment, the first and second pressing plates 9, 10, the first annular groove 22d and the second annular groove 22e are configured as described above. And lost.

  In the second embodiment, the axial portion of the rotor 21 is provided with a first recess 21a having an uneven strip 21c and a second recess 21b having an uneven strip 21d, and the secondary impact energy applied to the input shaft 1 is reduced. It can be absorbed by the frictional resistance between the ridges 1a and 21c. Further, there is a space for allowing relative movement of the input shaft 1 between the lower end of the input shaft 1 and the bottom surface of the first recess 21a. The output shaft 3 is fitted in the second recess 21b so that relative movement and relative rotation are impossible. The first recess 21a constitutes an impact energy absorbing hole.

In the second embodiment, when secondary impact energy is applied to the input shaft 1, the input shaft 1 moves relative to the rotor 21 in the first recess 21 a to absorb the secondary impact energy. it can. The output shaft 3 may be configured to be fitted in the second recess 21b so that the primary impact energy applied to the output shaft 3 can be absorbed by the frictional resistance between the ridges 3a and 21d.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.

Embodiment 3
FIG. 5 is an enlarged cross-sectional view showing the configuration of the third embodiment of the electric power steering apparatus. The electric power steering apparatus according to the third embodiment eliminates the absorption of impact energy by the output shaft 3 and the frame 22, and absorbs the secondary impact energy by the first recess 21a of the rotor 21 in which the input shaft 1 is movably fitted. The input shaft 1 is configured so that one end of the input shaft 1 is connected to the steering wheel A, and one end of the input shaft 1 is connected to the other end of the first shaft 1b by a torsion bar 13. A rolling bearing 14 supporting the first shaft body 1b, and having a second shaft body 1c fitted in the first recess 21a as an impact energy absorbing hole at the other end. A rolling bearing 15 for supporting the second shaft body 1c and a detector 16 for detecting a steering torque applied to the first shaft body 1b are provided.

  In the third embodiment, the rotor 21 is connected to the first recess 21a, and is provided with a third recess 21e having a diameter larger than that of the rolling bearing 15 and a second recess 21b. In addition, the uneven | corrugated strip is not provided in the 1st recess 21a and the 2nd recess 21b. The frame 22 includes a cylindrical peripheral wall portion 22f and first and second lid portions 22g and 22h each having a through hole at the center thereof and closing both ends of the cylindrical peripheral wall portion 22f.

  The first lid portion 22g has two plate bodies 22i and 22j in which the through holes are formed. The rolling bearing 15 is loosely fitted in the through holes of the inner plate body 22i, and the outer plate body 22j. The rolling bearing 14 is fitted and fixed in the through-hole of this, and the detector 16 is arranged in the space between both plate bodies 22i and 22j.

  The second lid portion 22h has a plate body 22k having a through hole and a bowl-shaped cover 22m, and a rolling bearing 17 is fitted into the through-hole of the plate body 22k. A detector 18 for detecting the steering torque applied to the output shaft 3 and the position of the rotor 21 is disposed.

  The first shaft body 1b is formed to have a larger diameter than the second shaft body 1c, and the other end portion of the first shaft body 1b is connected to the cylindrical portion 1d in which the second shaft body 1c is loosely fitted and the cylindrical portion 1d. A fitting hole 1e into which one end of the torsion bar 13 is fitted is provided. One end portion of the second shaft body 1c is provided with a fitting hole 1f into which the other end portion of the torsion bar 13 is fitted, and both end portions of the torsion bar 13 are first formed by dowel pins 18 and 19 penetrating the both end portions. The shaft body 1b and the second shaft body 1c are coupled. Further, the vicinity of the cylindrical portion 1d of the first shaft 1b is supported by the outer plate 22j by the rolling bearing 14, and the central portion of the second shaft 1c is supported by the inner plate 22i by the rolling bearing 15. Yes.

  The detector 16 is a detection rotor 16a that is externally fitted and fixed to the cylindrical portion 1d of the first shaft body 1b, and a detection stator 16b that is disposed around the detection rotor 16a and is held in a space within the lid portion 22g. The change of the rotation position of the detection rotor 16a is detected by the detection stator 16b as a change of impedance, and the steering torque is detected.

  The detector 18 includes a resolver having a detection rotor 18a that is externally fitted and fixed to the output shaft 3, and a detection stator 18b that is disposed around the detection rotor 18a and is held in a space within the lid portion 22h. The change of the rotation position of the detection rotor 18a is detected by the detection stator 18b as a change of impedance, and the steering torque applied to the output shaft 3 and the rotation position of the rotor 21 are detected.

  In the third embodiment, the torsion bar 13 is twisted by the steering torque applied to the input shaft 1, the steering torque applied to the input shaft 1 is detected by the detector 16, and electric power is applied based on the torque detected by the detector 16. The motor 2 is driven, and the rotation of the electric motor 2 is transmitted to the output shaft 3.

FIG. 6 is an explanatory diagram showing a state after absorbing the secondary impact energy. When secondary impact energy is applied to the input shaft 1, the first shaft body 1 b, the torsion bar 13, the second shaft body 1 c, the detection rotor 16 a and the rolling bearing 15 move together to form the second shaft body. The secondary impact energy can be absorbed by the frictional resistance between 1c and the first recess 21a. In this case, the rolling bearing 15 moves into the third recess 21e, and the detection rotor 16a moves to the place where the rolling bearing 15 was disposed. Since the rolling bearing 15 and the detection rotor 16a move in this way, it is easy to set the frictional resistance between the second shaft body 1c and the first recess 21a, and hence the impact energy absorption force, with high accuracy. Moreover, after absorbing the secondary impact energy, it can be repaired by exchanging the second shaft body 1c.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.

Embodiment 4
FIG. 7 is an enlarged cross-sectional view showing the configuration of Embodiment 4 of the electric power steering apparatus. In the electric power steering apparatus of the fourth embodiment, the input shaft 1 is press-fitted into the first recess 21a of the rotor 21 in the first embodiment, and the electric motor is axially connected to the second recess 21b of the rotor 21 with respect to the output shaft. An insertion hole that can be moved in the direction, the output shaft 3 is loosely fitted in the second recess 21b, and the electric motor 2 can be moved in the axial direction with respect to the output shaft 3, so that telescopic adjustment can be performed. It is configured.

In the fourth embodiment, the input shaft 1 is press-fitted into the first recess 21 a of the rotor 21 and is configured to rotate integrally with the rotor 21.
The output shaft 3 is supported by the vehicle body, and the projections and recesses 3a and 21d are provided in the outer periphery of the output shaft 3 and the second recess 21b (insertion hole) of the rotor 21, and are serrated and fitted so as to be relatively movable. The electric motor 2 is configured to move with respect to the output shaft 3. A transmission shaft 31 is connected to the lower end of the output shaft 3 by a universal shaft joint 30.

FIG. 8 is an explanatory diagram showing a state after telescopic adjustment in the fourth embodiment. In the fourth embodiment, telescopic adjustment can be performed by moving the input shaft 1 and the electric motor 2 in the axial length direction with respect to the output shaft 3. In this case, since the output shaft 3 is stationary, it is possible to avoid changing the angle of the transmission shaft 31 connected to the lower end of the output shaft 3 by the universal shaft joint 30 with respect to the output shaft 3 (steering shaft). It is possible to prevent the applied steering torque from changing, and to obtain a good steering feeling.
Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof and description of operations and effects are omitted.

  In the embodiment described above, the impact is formed of the first recess 21a and the second recess 21b which are provided with the steering shaft including the input shaft 1 and the output shaft 3 and into which the input shaft 1 and the output shaft 3 are fitted. Although the rotor 21 is provided with the energy absorbing hole, it also has one steering shaft in which the input shaft 1 and the output shaft 3 are integrally connected, and one impact energy absorbing hole through which the steering shaft passes. The rotor 21 is provided with a hole so that the primary impact energy applied to the steering shaft or the secondary impact energy applied to the steering wheel can be absorbed by the frictional resistance between the steering shaft and the impact energy absorbing hole. Good. Further, between the input shaft 1 and the first recess 21a, between the output shaft 3 and the second recess 21b, and between the steering shaft and the impact energy absorbing hole, an impact energy absorbing ring or a coating is used. You may make it the structure which provided the impact energy absorption layer. Moreover, although the outer peripheral part of the input shaft 1 and the output shaft 3, and the 1st recessed part 21a and the 2nd recessed part 21b were provided with the uneven | corrugated strip, it is also possible to set it as the non-circular cross-sectional shape which cannot make a relative rotation. Good.

  In the first embodiment described above, the rotor 21 is provided with the first recess 21a and the second recess 21b, and the frame 22 is provided with the first annular groove 22d and the second annular groove 22e, so that the primary impact energy and the second However, the rotor 21 is provided with the first recess 21a or the second recess 21b, and the frame 22 is provided with the first annular groove 22d or the second annular groove 22e. It may be configured to be able to absorb the primary impact energy or the secondary impact energy.

  In addition to the configuration in which the impact energy is absorbed by the rotor 21 and the frame 22 as in the first embodiment, and the configuration in which the impact energy is absorbed by the rotor 21 as in the second embodiment, (a 3) As shown in FIG. 3A, the frame 22 may absorb the impact energy. When the secondary impact energy is absorbed by the frame 22, for example, a cylindrical housing is loosely fitted to the input shaft 1 (steering shaft) on the side of the steering wheel A from the frame 22, and the lower portion of the housing is attached to the lower portion of the frame 22. Transmission means such as a retaining ring and a rolling bearing that abuts against the first wall portion 22a and transmits the secondary impact energy applied to the input shaft 1 to the housing between the upper portion of the housing and the input shaft 1 is provided. The impact energy may be transmitted from the input shaft 1 to the housing via the transmission means, and the housing may be moved in the axial direction to plastically deform the first wall portion 22a of the frame 22. In addition, as a means for plastically deforming the first wall portion 22a and the second wall portion 22b, a plastic deformation permitting portion including a first annular groove 22d and a second annular groove 22e is provided. Since it is good also as a structure which provided the plastic deformation permission part which has an annular groove, a some recess, etc. in the side surface of the 1st wall part 22a and the 2nd wall part 22b, the means to carry out a plastic deformation is not restrict | limited.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged cross-sectional view showing a configuration of a first embodiment of an electric power steering device according to the present invention. It is explanatory drawing which shows the process which absorbs the primary impact energy of the electric power steering apparatus which concerns on this invention. It is explanatory drawing which shows the process which absorbs the secondary impact energy of the electric power steering apparatus which concerns on this invention. It is an expanded sectional view which shows the structure of Embodiment 2 of the electric power steering apparatus which concerns on this invention. It is an expanded sectional view which shows the structure of Embodiment 3 of the electric power steering apparatus which concerns on this invention. In Embodiment 3, it is explanatory drawing which shows the state after absorbing secondary impact energy. It is an expanded sectional view which shows the structure of Embodiment 4 of the electric power steering apparatus which concerns on this invention. In Embodiment 4, it is explanatory drawing which shows the state after performing telescopic adjustment.

Explanation of symbols

1 Input shaft (steering shaft)
1b 1st shaft body 1c 2nd shaft body 2 Electric motor 3 Output shaft (steering shaft)
13 Torsion bar 21 Rotor 21a First recess (impact energy absorption hole)
21b Second recess (impact energy absorption hole, insertion hole)
22 Frame 23 Stator A Steering wheel (steering member)

Claims (6)

  In the electric power steering apparatus in which steering assist is performed by rotation of an electric motor for assisting steering arranged coaxially with a steering shaft that rotates in response to an operation of a steering member, the electric motor has the steering shaft that has the steering shaft. An electric power steering apparatus comprising a rotor having a shock energy absorbing hole that is movably fitted by impact energy applied to the motor.   In the electric power steering apparatus configured to assist steering by rotation of an electric motor for assisting steering disposed coaxially with a steering shaft that rotates in accordance with an operation of a steering member, the electric motor includes a rotor connected to the steering shaft; A stator disposed around the rotor, and a frame that supports the stator and that can be deformed in an axial direction of the steering shaft by impact energy applied to the steering shaft. Electric power steering device.   The steering shaft has an input shaft connected to the steering member and an output shaft through which the rotational force of the input shaft is transmitted through the rotor, and at least one of the input shaft and the output shaft is the impact energy. The electric power steering apparatus according to claim 1, wherein the electric power steering apparatus is fitted in the absorption hole.   The electric motor has a stator disposed around the rotor, and a frame that supports the stator and can be deformed in an axial direction of the steering shaft by impact energy applied to at least one of the input shaft and the output shaft. The electric power steering device according to claim 3.   The steering shaft has an input shaft connected to the steering member, and an output shaft to which a rotational force of the input shaft is transmitted through the rotor, and the input shaft is a first shaft body connected to the steering member. 2. An electric power steering apparatus according to claim 1, further comprising: a second shaft body coupled to the first shaft body by a torsion bar and fitted in the impact energy absorbing hole.   In an electric power steering apparatus that assists steering by rotation of a steering assisting electric motor having a rotor coaxially arranged with a steering shaft that rotates in accordance with an operation of the steering member, the steering shaft is connected to the steering member. An input shaft connected to the output shaft, and an output shaft to which a rotational force of the input shaft is transmitted via the rotor; the rotor is fitted with the output shaft, and the motor is moved in the axial direction with respect to the output shaft. An electric power steering apparatus having a fitting hole that allows a motor to move.

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