JP2017078500A - Damper device and steering device - Google Patents

Abstract

Disclosed is a damper device and a steering device that have improved impact absorption performance when the end of a turning shaft is applied. A damper device 50 is formed in a cylindrical shape with a shaft 21 having a shaft portion 211 and a large-diameter portion 51, and is inserted into the shaft 21 so as to be capable of relative movement in the axial direction, with respect to the end surface of the large-diameter portion 51. A housing 52 having a regulating surface 52b opposed in the axial direction, and an impact absorbing member 53 inserted through the shaft 211 and interposed between the end surface of the large-diameter portion 51 and the regulating surface 52b. The impact absorbing member 53 includes an impact receiving member 53a including an annular portion 532 that can contact the end surface of the large-diameter portion 51, and a surface 532a on the regulating surface 52b side of the annular portion 532 between the regulating surface 52b. And a plurality of rubber elastic bodies 53b that are respectively arranged with a gap in the circumferential direction of the shaft portion 211 and are respectively fixed to the surface 532a of the annular portion 532 on the regulating surface 52b side. [Selection] Figure 6

Description

  The present invention relates to a damper device and a steering device using the damper device.

  Conventionally, there is a steering device that changes the direction of a steered wheel by reciprocating a steered shaft coupled to a steered wheel (tire) via a tie rod in the axial direction. The steered shaft is slidably accommodated in the housing. When the turning shaft reaches the limit of the reciprocating movement range, the large diameter portion formed at the end of the turning shaft collides with the housing, and the moving range of the turning shaft is physically restricted. Specifically, a force for moving the steered shaft in the axial direction is input as the driver operates the steering wheel. Alternatively, an excessive force for moving the steered shaft in the axial direction from the steered wheel to the steered shaft is input (reverse) by an action such as the steered wheel climbing on the curb. Then, when the steered shaft continues to move in the axial direction with the forward and reverse inputs, the large diameter portion eventually collides with the housing, resulting in “end contact”.

  At this time, in the steering device, there is a technique for absorbing an impact at the time of end contact by using a damper device for the end contact portion (see Patent Documents 1 and 2). The steering devices of Patent Literatures 1 and 2 include an impact absorbing member interposed between the end member (large diameter portion) and the housing. The shock absorbing member is a shock absorbing member constituting the damper device, and includes an end plate (shock receiving member) that contacts the large diameter portion and receives a collision shock, and an elastic body that elastically deforms to absorb the shock. The impact receiving member is formed with a contact surface that physically stops an end member that moves in the axial direction by contacting a predetermined portion of the housing. As described above, the impact absorbing member receives a collision from the large-diameter portion, and absorbs the collision impact by elastic deformation in the axial direction of the elastic body when the end member moves toward the housing. Thereafter, the contact surface collides with a predetermined part of the housing, and the end member (steering shaft) is stopped.

Japanese Patent No. 4255632 Japanese Patent Laid-Open No. 2014-100531

  However, in the techniques of Patent Documents 1 and 2, since the impact receiving member of the impact absorbing member abuts on a predetermined portion of the housing and suddenly stops the movement of the end member, the predetermined portion of the housing is stopped by the end member of the steered shaft. You will receive great power. As a reaction, the steered shaft also receives a large force. Thereby, there exists a possibility that the weakest weakest part may be damaged among the parts connected with a steered shaft or a housing.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a damper device and a steering device that have improved impact absorption performance when the end of a steered shaft is applied.

  In order to solve the above-mentioned problem, a damper device according to claim 1 is formed in a shaft having a shaft portion and a large-diameter portion, and in a cylindrical shape, and the shaft is inserted so as to be relatively movable in the axial direction. And a shock absorbing member that is inserted between the end surface of the large-diameter portion and the regulating surface between the housing and the housing having a regulating surface facing the axial direction with respect to the end surface of the shaft. The shock absorbing member includes an impact receiving member including an annular portion that can come into contact with an end surface of the large-diameter portion, a surface on the restriction surface side of the annular portion, and the restriction And a plurality of rubber elastic bodies that are respectively disposed with a gap therebetween in the circumferential direction of the shaft portion and fixed to the surface on the regulation surface side of the annular portion.

  In this way, the plurality of rubber elastic bodies are respectively disposed between the restriction surface side surface of the annular portion and the restriction surface of the housing and with a gap between them in the circumferential direction of the shaft portion. As described above, the plurality of rubber elastic bodies have many gaps that can be enlarged around. For this reason, even if the end surface of the large-diameter portion collides with the impact receiving member and presses the impact absorbing member in the axial direction to compress the plurality of rubber elastic bodies in the axial direction, the rubber elastic bodies are sufficiently in the direction in which there is a gap. Impact can be absorbed while elastically deforming.

It is the schematic which shows the electric power steering apparatus which concerns on this embodiment. It is sectional drawing of the steered shaft axial part of FIG. 1 for demonstrating a damper apparatus. It is sectional drawing explaining a steering assist mechanism. It is the figure which looked at the shock-absorbing member of a damper apparatus from the side contact | abutted with a control surface. It is a graph showing the relationship between a shape factor and the maximum impact force. In this embodiment, it is sectional drawing which shows the state of the impact-absorbing member of the axial end part of the steered shaft just before an end contact. In this embodiment, it is sectional drawing which shows the state of the impact-absorbing member of the axial end part of the steered shaft after end contact. It is a figure which shows the state of the rubber elastic body adjacent in the circumferential direction in the state of FIG.

  Hereinafter, specific embodiments of the damper device of the present invention and the steering device of the present invention using the damper device will be described with reference to the drawings. An electric power steering device will be described as an example of the steering device. The electric power steering device is a steering device that assists the steering force by the steering assist force. The steering device of the present invention can be applied to a rear wheel steering device, a steer-by-wire device, and the like in addition to the electric power steering device.

(1. Configuration of electric power steering device)
As shown in FIG. 1, the electric power steering device S includes a steering mechanism 10, a steering mechanism 20, a steering assist mechanism 30, a torque detection device 40, and a damper device 50. The steering mechanism 10 includes a steering wheel 11 and a steering shaft 12. The steering wheel 11 is fixed to the end of the steering shaft 12. The steering shaft 12 transmits a steering torque applied to the steering wheel 11 to steer the steered wheels 26 and 26. The steering shaft 12 is configured by connecting a column shaft 13, an intermediate shaft 14, and a pinion shaft 15. The pinion shaft 15 includes an input shaft 15a, an output shaft 15b, and a torsion bar 15c. The output side portion of the intermediate shaft 14 is connected to the input side portion of the input shaft 15a, and pinion teeth 15d are formed on the output side portion of the output shaft 15b.

  The steered mechanism 20 includes a steered shaft 21 (corresponding to a shaft) according to the present invention and a housing 22 formed in a substantially cylindrical shape (corresponding to a tubular shape). The housing 22 is made of, for example, aluminum. The steered shaft 21 is housed and supported in a housing 22 so as to be linearly reciprocable along the axial direction. In the following description, the direction along the axial direction of the steered shaft 21 is also simply referred to as “A-axis direction (see FIG. 1)”. The housing 22 includes a first housing 22a and a second housing 22b fixed to one end side (left side in FIG. 1) in the A-axis direction of the first housing 22a.

  The pinion shaft 15 is rotatably supported in the first housing 22a. Rack teeth 21 a are formed on the steered shaft 21, and the rack teeth 21 a and the pinion teeth 15 d are engaged with each other to form a rack and pinion mechanism 23.

  As shown in FIGS. 1 and 2, the steered shaft 21 has large diameter portions 51 and 51 at both ends. The large diameter portions 51 and 51 are formed by expanding both ends of the steered shaft 21. In FIG. 2, only the left large-diameter portion 51 in FIG. 1 is shown, and the right large-diameter portion 51 is not shown. As shown in FIG. 2, a ball stud 27 is accommodated in the large diameter portion 51 (51) to form a ball joint. A tie rod 24 (24) (see FIG. 1) is connected to both ends of the ball stud 27 (27), and a tip of the tie rod 24 (24) is connected to a knuckle (not shown) to which the steered wheels 26 are assembled.

  Thus, when the steering wheel 11 is steered, the steering torque is transmitted to the steering shaft 12, and the pinion shaft 15 is rotated. The rotation of the pinion shaft 15 is converted into a linear reciprocating movement of the steered shaft 21 by the pinion teeth 15d and the rack teeth 21a. The movement along the A-axis direction is transmitted to the knuckle (not shown) via the tie rod 24 (24), whereby the steered wheels 26 and 26 are steered, and the traveling direction of the vehicle is changed. Reference numeral 25 denotes a boot for maintaining the airtightness of the accommodation space of the steering mechanism 20 including the inside of the housing 22.

  The steering assist mechanism 30 is a mechanism that applies a steering assist force to the steering mechanism 10 using the motor M controlled based on the output of the torque detection device 40 as a drive source. As shown in FIG. 3, the steering assist mechanism 30 includes a steering assist device housing 22c, a bulging portion 22d, an electrical device housing 31, an electrical device MCU, an output shaft 32 of a motor M, a ball screw mechanism 33, and a belt transmission mechanism. 35. The steering assist mechanism 30 transmits the rotational torque of the motor M to the ball screw mechanism 33 via the belt transmission mechanism 35, and the rotational torque is converted into a linear reciprocating movement force of the steered shaft 21 by the ball screw mechanism 33. Thus, a steering assist force is applied to the steering mechanism 10. That is, the electric power steering apparatus S of the present embodiment is configured as a so-called rack parallel type apparatus.

  A large portion of the steering assist mechanism 30 (portion attached to the steered shaft) is a joint portion between the first housing 22a and the second housing 22b, and the housing 22 is formed in a large-diameter cylindrical shape having an enlarged diameter. The steering assist device housing 22c, which forms a part of the steering assist device, is disposed and accommodated. A bulging portion 22d having a bulging cylindrical shape is provided below the steering assist device housing 22c. In the bulging portion 22d, a device that is arranged in parallel with being separated from the steered shaft 21 in the steering assist mechanism 30 is accommodated and arranged. The steering assist device housing 22c and the bulging portion 22d form one continuous accommodation space. An electrical equipment housing 31 that houses the electrical equipment MCU is attached to the end face of the bulging portion 22d. The bulging portion 22d and the electrical device housing 31 communicate with each other through a predetermined through hole.

  The electrical device MCU including the motor M is housed in the electrical device housing 31 while being separated from the steered shaft 21. The output shaft 32 of the motor M is arranged in parallel with the A-axis direction of the steered shaft 21 and extends into the bulging portion 22d. The output shaft 32 is an output shaft of the motor M and transmits a steering assist force. The drive pulley 36 is disposed outside the electrical device housing 31 in the A-axis direction on the outer peripheral surface of the output shaft 32 and is accommodated in the bulging portion 22d. The electrical equipment MCU includes a motor M and a control unit ECU for driving the motor M.

  The ball screw mechanism 33 includes a ball screw portion 21b and a ball screw nut 33a (corresponding to a nut). The ball screw portion 21b is formed over a certain range along the A-axis direction on the outer periphery of the steered shaft 21 shown in FIG. 1 (left side in FIG. 1). The ball screw nut 33a is screwed to the ball screw portion 21b of the steered shaft 21 via a plurality of balls 33b arranged along the ball screw portion 21b.

  The belt transmission mechanism 35 includes the drive pulley 36, the toothed belt 35a, and the driven pulley 34 described above. The drive pulley 36 and the driven pulley 34 are toothed pulleys each having external teeth. The belt transmission mechanism 35 is a mechanism that transmits a driving force (rotational driving force or torque) generated by the motor M between the driving pulley 36 and the driven pulley 34 via the toothed belt 35a. The drive pulley 36 transmits rotational torque (rotational driving force) to and from the output shaft 32 of the motor M.

  The toothed driven pulley 34 is fixed to the outer periphery of the ball screw nut 33a so as to be integrally rotatable with the ball screw nut 33a. The toothed belt 35a is an annular rubber belt having a plurality of inner teeth on the inner peripheral side, and meshes with each tooth provided on each outer periphery between the outer periphery of the driven pulley 34 and the outer periphery of the drive pulley 32a. The rotation of the toothed drive pulley 32a is transmitted to the toothed driven pulley 34 without slipping. The toothed belt 35a is a rubber belt and is the weakest part of the electric power steering device S.

  With the above configuration, the steering assist mechanism 30 drives the motor M according to the rotation operation of the steering wheel 11 to rotate the output shaft 32. As the output shaft 32 rotates, the transmission torque is transmitted to the drive pulley 36, and the drive pulley 36 rotates. The rotation of the drive pulley 36 is transmitted to the driven pulley 34 via the toothed belt 35a. As the driven pulley 34 rotates, the ball screw nut 33a provided integrally with the driven pulley 34 rotates. When the ball screw nut 33a rotates, the steering assist force in the axial direction of the steered shaft 21 is transmitted to the steered shaft 21 via the ball 33b.

  The torque detection device 40 is fixed to the mounting opening 22e of the housing 22 around the pinion shaft 15. The torque detection device 40 detects the amount of twist of the torsion bar 15c and outputs a signal corresponding to the amount of twist to the control unit ECU. Here, the torsion bar 15c is a member having a characteristic of being twisted according to the difference between the torque of the input shaft 15a and the torque of the output shaft 15b. The control unit ECU determines the steering assist torque based on the output signal of the torque detection device 40 and controls the output of the motor M. The control unit ECU determines the steering center by learning control based on the neutral information stored in advance and the traveling state. The neutral information is the position (electrical angle) information of the angle sensor of the motor M corresponding to the steering center, is measured at the time of vehicle assembly, and is stored in a nonvolatile memory in the control unit ECU.

(2. Damper device)
The damper device 50 will be described. In the present embodiment, the damper device 50 is mounted on two left and right sides in the A-axis direction of the electric power steering device S on the front wheel side in a four-wheel vehicle. The damper device 50 includes a large-diameter portion 51 included in the steered shaft 21 as a positive input associated with steering by the driver or a reverse input from the outside of the vehicle via the steered wheels is input to the steered shaft 21. Is a device for absorbing an impact when colliding with the regulating surface 52b of the housing.

  As shown in FIG. 2, the damper device 50 includes the above-described steered shaft 21 (corresponding to a shaft), large-diameter portion housings 52 and 52 (housing 22), and impact absorbing members 53 and 53. 2 is different from the state of FIG. 1 in that the large-diameter portion 51 is in contact with the shock absorbing member 53 in the A-axis direction. In order to stop the linear movement of the steered shaft 21, the shock absorbing members 53, 53 are respectively accommodated in the spaces in the large-diameter housings 52, 52, and the large-diameter portions 51, 51 of the steered shaft 21 are large. It is interposed between the restricting surfaces 52b and 52b of the diameter housings 52 and 52, respectively. Then, for example, when the steered shaft 21 moves to the right in FIGS. 1 and 2 in the A-axis direction and the steered wheel 26 reaches the maximum steering angle, the large-diameter portion 51 becomes the shock absorbing member 53. Colliding (see FIG. 2). The shock absorbing member 53 absorbs the impact of the collision that occurs at this time. In the following description, the configuration of the damper device 50 on the side adjacent to the steering assist mechanism 30 in FIG. 1 (left side in FIG. 1) among the damper devices 50 mounted at two locations unless otherwise specified. , Mainly explained.

  The large-diameter portion 51 of the steered shaft 21 is connected to the steered shaft 21 at the end portion 511 on the steered shaft 21 side, and has a larger diameter than the shaft portion 211 at the end portion of the steered shaft 21. A female screw portion 213 that opens toward the large-diameter portion 51 is formed on the end surface of the shaft portion 211 of the steered shaft 21. Further, the end portion 511 is formed with a male screw portion 51 b that is screwed with the female screw portion 213 of the steered shaft 21. The external thread 51b protrudes toward the steered shaft 21 side. The steered shaft 21 and the ball stud 27 are connected to each other through the large-diameter portion 51 by the male screw portion 51 b being screwed to the female screw portion 213.

  Further, an end surface of the steered shaft 21, that is, a contact end surface 51a (corresponding to an end surface of the large diameter portion) of the large diameter portion 51 with which the terminal end contacts is formed at the root of the male screw portion 51b. The contact end face 51a is formed radially outward from the root of the external thread 51b. In the present embodiment, the contact end surface 51a is a so-called rack end corresponding to the end of the steered shaft 21, and the contact end surface 51a can contact the regulation surface 52b when the shock absorbing member 53 is not mounted. It serves as a stopper when the steered shaft 21 reciprocates linearly.

  The large-diameter portion 51 connects the ball stud 27 at the end 512 opposite to the steered shaft 21 side, and connects the steered wheel 26 via the ball stud 27, the tie rod 24, and the knuckle. That is, the large diameter portion 51 is a socket that accommodates the ball stud 27 on the end portion 512 side. The ball stud 27 whose tip on the large diameter portion 51 side has a ball shape is rotatably accommodated in the accommodating portion 51c via the cushioning material 27c. A portion of the ball stud 27 opposite to the large diameter portion 51 is formed in a rod shape, and an end portion of the rod and a knuckle for connecting the steered wheel 26 are connected through a tie rod 24. As a result, when the steered shaft 21 moves linearly in the A-axis direction, the tie rod 24 is swung around the ball portion 27b attached to the large-diameter portion 51. And the steered wheel 26 connected to a knuckle is steered until the contact end surface 51a contacts the impact absorbing member 53 and the movement is restricted. That is, a positive input is made.

  The large-diameter portion housing 52 is a part of the housing 22 connected to the end portions of the first and second housings 22a and 22b, and opens to the side where the steered wheels 26 are arranged along the A-axis direction. It is formed in a substantially bottomed cylindrical shape. Inside the large-diameter portion housing 52, a shaft accommodating portion 52e that accommodates the shaft portion 211 of the steered shaft 21 in an inserted state, and opens in the A-axis direction, and can accommodate the shaft portion 211 and the large-diameter portion 51. A large-diameter portion accommodating portion 52a is formed. The large-diameter portion accommodating portion 52 a is formed so that the inner diameter is maintained substantially constant, and the bottom surface forming the bottom wall forms a regulating surface 52 b that faces the contact end surface 51 a of the large-diameter portion 51.

  Further, the inner peripheral surface 52c of the large-diameter portion accommodating portion 52a, and the bottom corner that is erected in the axial direction from the regulating surface 52b is radially outward so as to be flush with the regulating surface 52b. A recessed portion 52d is formed to be recessed toward the direction. The recesses 52d are provided at four locations at equal intervals in the circumferential direction around the axis on the inner peripheral surface 52c (only two locations are shown in FIG. 2). The four recesses 52d are formed so as to accommodate a total of four protrusions 536 respectively formed on four rubber elastic bodies 53b of an impact absorbing member 53 described later. That is, the concave portion 52d is a concave portion for fitting with the convex portion 536 of the rubber elastic body 53b to position the shock absorbing member 53 in the A-axis direction. Note that the shape of the concave portion 52d is not limited as long as the impact absorbing member 53 can be positioned in the A-axis direction in a state where the convex portion 536 can be accommodated and the convex portion 536 is accommodated.

  As described above, the impact absorbing member 53 is inserted between the shaft portion 211 of the steered shaft 21 and between the contact end surface 51a of the large diameter portion 51 and the restriction surface 52b of the large diameter portion housing 52 in the A-axis direction. It is a member that is interposed between the two and absorbs a collision impact at the time of “end contact”. The impact absorbing member 53 includes an iron impact receiving member 53a having an L-shaped cross-sectional view along the A-axis direction, and four (corresponding to a plurality) rubber elastic bodies 53b. As shown in FIG. 2, the impact receiving member 53a includes a cylindrical portion 531 facing the inner peripheral surface 52c of the large diameter portion housing 52 (housing). Further, the impact receiving member 53a extends radially outward from the cylindrical portion 531, faces the regulating surface 52b, and is a flange portion 532 as an annular portion that can come into contact with the contact end surface 51a of the large diameter portion 51. Is provided. The impact receiving member 53a is a part that receives impact force due to contact or collision by the contact end surface 51a of the large-diameter portion 51 in the flange portion 532, and transmits and attenuates the impact while applying compressive force to the rubber elastic body 53b.

  The cylinder portion 531 has a substantially straight cylindrical shape. An inner peripheral surface 531 a of the cylindrical portion 531 is formed as a through hole for inserting the shaft portion 211 in a state where the inner peripheral surface 531 a is attached to the large-diameter portion housing 52 as the shock absorbing member 53. A height h (see FIG. 6) of the cylindrical portion 531 along the A-axis direction is formed corresponding to a compression allowance X of an impact absorbing member 53 described later. Specifically, in the undeformed state of the rubber elastic body 53b included in the shock absorbing member 53 disposed in the large-diameter portion housing 52, the distance D in the A-axis direction between the end surface 531c of the cylindrical portion 531 and the regulating surface 52b is: The height h of the cylindrical portion 531 is adjusted so as to be larger than the compression allowance X. The cylindrical portion 531 also has a function of restricting elastic deformation of the rubber elastic body 53b particularly in the inner diameter direction of the inner peripheral surface 534, and the rubber elastic body 53b protrudes inward in the radial direction beyond the cylindrical portion 531. To prevent.

  The flange portion 532 has an annular plate shape extending from the cylindrical portion 531 outward in the radial direction and having a substantially uniform thickness. The outer diameter of the flange portion 532 is slightly smaller than the inner diameter of the inner peripheral surface 52c of the large diameter portion housing 52 (so as to have a gap of about 0.1 to 0.3 mm).

  When the large-diameter portion 51 does not apply an impact force to the flange portion 532, the four rubber elastic bodies 53b include the inner peripheral surface 52c of the large-diameter portion housing 52 (housing) and the regulating surface 52b of the large-diameter portion housing 52. The cylindrical portion 531 is disposed in a space formed by the outer peripheral surface 531 b and the flange portion 532. As shown in FIGS. 2, 4, and 6, the four rubber elastic bodies 53 b are between the inner peripheral surface 52 c of the large-diameter portion housing 52 and between the outer peripheral surface 531 b of the cylindrical portion 531. Are arranged through a predetermined gap. In addition, the four rubber elastic bodies 53b are each formed in a circular arc shape in a cross section orthogonal to the axis around the axis, and are provided at equal intervals in the circumferential direction. At this time, as shown in FIG. 4, the four rubber elastic bodies 53 b are arranged with a predetermined gap between the rubber elastic bodies 53 b adjacent in the circumferential direction. Then, the four rubber elastic bodies 53b are arranged between the regulating surface 52b and the regulating surface 52b of the flange portion 532 (annular portion) in this way, and the end surfaces thereof are respectively on the surface 532a. Vulcanized and fixed.

  The four rubber elastic bodies 53b are large with respect to the pressure receiving area SR which is a contact area (bonding area) with the flange portion 532 (annular portion) when the large diameter portion 51 does not apply an impact force to the flange portion 532. The ratio (SF / SR) of the free area SF that is the surface area of each of the opposing surfaces of the inner peripheral surface 52c of the diameter portion housing 52, the outer peripheral surface 531b of the cylindrical portion 531 and the adjacent rubber elastic body 53b, that is, the shape ratio Is set to a range having a predetermined width α including 1.5. That is, the surface area of the four rubber elastic bodies 53b facing the inner peripheral surface 52c of the large-diameter portion housing 52 is SF1, and the surface area of the four rubber elastic bodies 53b facing the outer peripheral surface 531b of the cylindrical portion 531 is SF2. When the surface area of the four rubber elastic bodies 53b facing the adjacent rubber elastic bodies 53b is SF3, the upper limit value and the lower limit value of the shape ratio calculated by the equation (1) ((SF1 + SF2 + SF3) / SR) are In consideration of variation for each product, the size and tolerance of the rubber elastic body 53b are set so as to have a predetermined width α including 1.5. The predetermined width α may be set arbitrarily.

  In addition, the shape rate shown in Formula (1) is a well-known parameter | index used when determining the shape of a rubber elastic body so that it may have a desired shock absorption characteristic. As a reference, a known graph showing the relationship between the shape factor and the maximum impact force is shown (FIG. 5). In the graph of FIG. 5, the horizontal axis represents the shape ratio. The vertical axis indicates the maximum impact force actually detected when an impact assuming 500 kN, for example, is applied to the rubber elastic body to be evaluated. As can be seen from the graph of FIG. 5, the rubber elastic body has better shock absorption characteristics as the shape ratio increases. However, if the shape ratio is too large, deformation and destruction are likely to occur. Therefore, the inventor repeats the experiment, and when the upper and lower limit values of the shape ratio are in the range of the predetermined width α including 1.5, the inventor ensures durability against deformation or breakage and has good shock absorption characteristics. Is set as described above.

  Further, as described above, the four rubber elastic bodies 53b include the convex portions 536 that protrude outward in the radial direction of the shaft portion 211 at the end portion on the regulating surface 52b side of the outer peripheral surface (see FIGS. 2 and 4). ). As a result, the convex portion 536 is press-fitted (accommodated) into the four concave portions 52 d formed corresponding to the convex portions 536 on the inner peripheral surface 52 c of the large-diameter portion housing 52 described above, and the shock absorbing member 53. The position in the axial direction is fixed (restricted).

(3. Action)
In the damper device 50, when the large-diameter portion 51 gives an impact force to the flange portion 532, the four rubber elastic bodies 53 b are sandwiched between the regulating surface 52 b and the flange portion 532 starting from the state shown in FIG. It is pressed (compressed) in the axial direction. For this reason, the four rubber elastic bodies 53b are each filled with an initial clearance space provided in the periphery thereof, so that the inner peripheral surface 52c, the regulating surface 52b, the cylindrical portion of the large-diameter portion housing 52 (housing 22). The outer peripheral surface 531b of 531 and the flange portion 532 are deformed while being in contact with each other. At the same time, it is deformed while being in contact with the rubber elastic body 53b adjacent in the circumferential direction (none of which is shown).

  Finally, as shown in FIGS. 7 and 8, the four rubber elastic bodies 53 b are composed of the inner peripheral surface 52 c of the large-diameter portion housing 52, the housing regulating surface 52 b, and the outer peripheral surface of the cylindrical portion 531. 531b, the flange portion 532 after being displaced by X in the A-axis direction, and the entire surface facing the rubber elastic body 53b adjacent in the circumferential direction are compressed and deformed. That is, as shown in FIGS. 7 and 8, the four rubber elastic bodies 53b after the compression deformation are filled inside the space after compression displaced by X in the A-axis direction.

  Thereby, the impact force which the large diameter part 51 provided to the flange part 532 is favorably absorbed by the four rubber elastic bodies 53b. Since the rubber elastic body 53b is an incompressible fluid, it is not displaced further in the A-axis direction. For this reason, the cylindrical portion 531 of the impact receiving member 53a does not come into contact with the regulating surface 52b, and remains in a non-contact state with respect to the regulating surface 52b, and is deformed by the deformed rubber elastic body 53b. The relative movement with respect to the housing) is restricted. For this reason, when the end surface 531c of the cylinder part 531 collides with the regulation surface 52b, a large impact force is generated, and among the parts connected to the steered shaft 21 and the large-diameter portion housing 52 by the generated impact force. There is no risk that the weakest part will be impacted and damaged.

(4. Effects of the embodiment)
According to the above embodiment, the damper device 50 is formed in a cylindrical shape with the steered shaft 21 (shaft) including the shaft portion and the large-diameter portion, and is capable of relatively moving the steered shaft 21 (shaft) in the axial direction. The large-diameter portion housing 52 (housing 22) having a regulating surface 52b that is axially opposed to the abutting end surface 51a (end surface) of the large-diameter portion 51 is inserted into the large-diameter portion. And an impact absorbing member 53 interposed between the contact end surface 51a of the 51 and the regulating surface 52b in the axial direction. The shock absorbing member 53 includes an impact receiving member 53a having an annular portion that can come into contact with the contact end surface 51a (end surface) of the large diameter portion 51, a surface on the regulating surface 52b side of the annular portion, and a regulating surface 52b. 4 (plural) rubber elastic bodies 53b, which are respectively disposed with a gap therebetween in the circumferential direction of the shaft portion 211 and fixed to the surface of the annular portion on the regulating surface 52b side. .

  In this way, the four (plural) rubber elastic bodies 53b are mutually connected in the circumferential direction of the shaft portion 211 between the ring-side restriction surface 52b side surface and the large-diameter portion housing 52 restriction surface 52b. Are arranged with a gap therebetween. For this reason, even if the contact end surface 51a of the large-diameter portion 51 collides with the impact receiving member 53a, presses the impact absorbing member 53 in the axial direction, and the four (plural) rubber elastic bodies 53b are compressed in the axial direction. Since the rubber elastic body 53b has many gaps that can be expanded in the periphery, it can be freely compressed and deformed to absorb the impact well.

  Further, according to the above embodiment, the impact receiving member 53a of the damper device 50 includes the cylindrical portion 531 facing the inner peripheral surface of the large-diameter portion housing 52 (housing 22), and radially outward from the cylindrical portion 531. And a flange portion 532 serving as an annular portion that can contact the large-diameter portion 51 while facing the regulating surface 52b. The four (plural) rubber elastic bodies 53b are arranged in a space formed by the inner peripheral surface 52c of the large-diameter portion housing 52, the regulating surface 52b, the outer peripheral surface 531b of the cylindrical portion 531 and the flange portion 532, The four (plural) rubber elastic bodies 53b are formed between the large-diameter portion 51 and the outer peripheral surface of the cylindrical portion 531 when the large-diameter portion 51 does not apply an impact force to the flange portion 532. It arrange | positions through a clearance gap between. As a result, the four (plural) rubber elastic bodies 53b are compressed in the axial direction and are blocked by the cylindrical portion 531 even when trying to expand inward in the outer diameter direction around the axis, and the steered shaft 21 (shaft). It does not abut against the shaft portion 211. Therefore, the durability of the rubber elastic body 53b is improved.

  Further, according to the above-described embodiment, in the damper device 50, the four (plural) rubber elastic bodies 53b are pressed in the axial direction by the regulating surface 52b and the flange portion 532 so as to fill the gap. The inner peripheral surface 52c of the diameter portion housing 52 (housing 22), the regulating surface 52b, the outer peripheral surface 531b of the cylindrical portion 531 and the flange portion 532 are deformed. Further, the four (plural) rubber elastic bodies 53b are deformed so as to be in contact with the rubber elastic bodies 53b adjacent in the circumferential direction. For this reason, since the rubber elastic body 53b is fully filled in the gap, the impact receiving member 53a can no longer move in the axial direction. Accordingly, the impact receiving member 53a is restricted from relative movement with respect to the large-diameter portion housing 52 (housing 22) by the deformed rubber elastic body 53b while maintaining a non-contact state with respect to the restriction surface 52b.

  Thus, the impact receiving member 53a according to the damper device 50 restricts relative movement with respect to the large-diameter portion housing 52 by the deformed rubber elastic body 53b while maintaining a non-contact state with respect to the restriction surface 52b. Therefore, the rubber elastic body 53b is disposed between the large-diameter portion housing 52 and the large-diameter portion 51, in contrast to the configuration in which the impact receiving member collides with the housing in the prior art to restrict the relative movement of the shock-absorbing member relative to the housing. Since it is configured to continue to act by intervening, it has excellent shock absorption. For this reason, when the end surface 531c of the cylinder part 531 collides with the regulating surface 52b, a large impact force is generated, and the generated impact force is coupled to the steered shaft 21 or the large-diameter portion housing 52 (housing 22). There is no risk of damaging the weakest of the parts.

  Further, according to the above embodiment, in the damper device 50, each of the four (plural) rubber elastic bodies 53b includes the convex portions 536 that project outward in the radial direction of the shaft portion 211 on each outer peripheral surface. The large-diameter portion housing 52 (housing 22) is formed on the inner peripheral surface 52c of the large-diameter portion housing 52 so as to correspond to the respective convex portions 536 and accommodates the respective convex portions 536 (a plurality of plural pieces). ) Recess 52d. Thereby, the movement to the axial direction of the damper apparatus 50 can be controlled easily.

  Further, according to the embodiment, in the damper device 50, the four (plural) rubber elastic bodies 53b are formed in an arc shape, and four (three or more) are provided at equal intervals in the circumferential direction. Thereby, the area of the opposing surface which mutually opposes is securable enough between the rubber elastic bodies 53b adjacent to the circumferential direction. Thereby, when the large diameter portion 51 gives an impact force to the flange portion 532 and the rubber elastic body 53b is compressed and deformed in the axial direction, the rubber elastic body 53b is not only radially outward and radially inward. Since deformation is possible also in the circumferential direction, it is suitable for shock absorption.

  Further, according to the embodiment, in the damper device 50, the four (a plurality of) rubber elastic bodies 53b are the large-diameter portion housing with respect to the pressure receiving area SR that is a contact area with the flange portion 532 that is an annular portion. The ratio of the free area SF that is the surface area of each of the opposing surfaces of the inner peripheral surface of 52, the outer peripheral surface 531b of the cylindrical portion 531 and the adjacent rubber elastic body 53b, that is, the upper and lower limit values of the shape ratio include 1.5. Is set to have a width α. As a result, the damper device 50 is easy to manufacture, has durability, and has good shock absorption characteristics.

  Further, according to the above embodiment, both ends of the damper device 50 of the steering device S are coupled to the steered wheels 26 and 26 via the tie rods 24 and 24. Further, the damper device 50 reciprocates in the axial direction to steer the steered wheels 26 and 26, and to the steered shaft 21 including large-diameter portions 51 and 51 that are swingably connected to the tie rod 24, A housing 22 that houses the rudder shaft 21 and an impact absorbing member 53 are provided. And when the large diameter part 51 gives the impact force to the flange part 532, the impact receiving member 53a is maintaining the non-contact state with respect to the control surface 52b. That is, the impact receiving member 53a is deformed and restricted from moving relative to the large-diameter portion housing 52 by the rubber elastic body 53b that fills the gap. Therefore, the rubber elastic body 53b is interposed between the housing and the large-diameter portion 51 and absorbs the shock in contrast to the conventional configuration in which the impact receiving member collides with the housing to restrict the relative movement of the shock absorbing member with respect to the housing. It becomes possible to continue to act against. For this reason, the damper device 50 is suitable as a steering device S for automobiles that have excellent shock absorption capability and high durability requirements.

  Further, according to the embodiment, the steering device S including the damper device 50 is attached to the housing 22 so as to be separated from the steering shaft 21, and the output shaft 32 extends into the housing 22, and the steering shaft 21. And a ball screw mechanism 33 having a ball screw portion 21b formed on the outer peripheral surface of the screw and a nut 33a screwed to the ball screw portion 21b via a plurality of balls, and a toothed portion provided on the output shaft 32 so as to be integrally rotatable. A belt transmission mechanism 35 including a driving pulley 36, a toothed driven pulley 34 provided integrally with the nut 33a, and a toothed belt 35a for transmitting a driving force between the driving pulley 36 and the driven pulley 34;

  Thus, in this embodiment, the steering device S is an electric power steering device of a type that assists the steering force by the steering assist force. For this reason, for example, if the steered wheels 26 and 26 ride on a curb or the like, the steered wheel 26 receives a force from the curb toward the maximum rudder angle direction (steer angle end direction), and the steered shaft 21 according to the force. Is moved in a straight line. That is, an excessive force that moves the steered shaft 21 in the axial direction from the steered wheels 26 and 26 to the steered shaft 21 may be reversely input. For this reason, the ball screw nut 33a that is screwed into the ball screw portion 21b is given a rotational force from the ball screw portion 21b, and rotates the driven pulley 34 in a predetermined direction. The driven pulley 34 applies a rotational force to the drive pulley 32a and the output shaft 32 of the motor M via the toothed belt 35a.

  Thereafter, the large-diameter portion 51 provided at the end of the steered shaft 21 comes into contact with the flange portion 532 of the shock absorbing member 53 of the damper device 50 by the further movement of the steered shaft 21 in the axial direction. At this time, for example, as in the prior art, when the contact surface of the cylindrical portion 531 of the impact receiving member 53a of the impact absorbing member 53 collides with the restriction surface 52b of the large-diameter portion housing 52 of this embodiment, the steered shaft. The movement of 21 stops abruptly. The rotations of the drive pulley 32a and the output shaft 32 of the motor M are not stopped but are continued by inertia. For this reason, the tension at one of the spanned portions of the toothed belt 35a spanned between the driven pulley 34 and the drive pulley 32a is excessively increased, and the tension at the other spanned portion is increased. Will loosen. Along with this, for example, the number of teeth engaged with the external teeth of the driving pulley 32a and the loose inner tooth of the toothed belt 35a decreases (tooth lift), and the internal teeth and the driving pulley 32a There is a possibility that the engagement with the external teeth will easily come off and tooth skipping may occur.

  However, in the present invention, in the shock absorbing member 53 of the damper device 50, four (plural) rubber elastic bodies 53b formed at an appropriate shape ratio are pressed in the axial direction by the regulating surface 52b and the flange portion 532. As a result, the rubber elastic body 53b fills all of the inner peripheral surface 52c of the large-diameter portion housing 52 (housing 22), the regulating surface 52b, the outer peripheral surface 531b of the cylindrical portion 531 and the flange portion 532 so as to fill the gap. Deforms to be in contact with the entire surface. Further, the rubber elastic body 53b is deformed so as to be in contact with the rubber elastic body 53b adjacent in the circumferential direction over the entire surface. The impact receiving member 53a is restricted in relative movement with respect to the large-diameter portion housing 52 (housing 22) by the deformed rubber elastic body 53b while maintaining a non-contact state with respect to the restriction surface 52b. Thereby, the end surface 531c of the cylindrical portion 531 of the impact receiving member 53a of the impact absorbing member 53 does not collide with the restriction surface 52b of the large diameter portion housing 52, and the movement of the steered shaft 21 does not stop suddenly. Therefore, tooth skipping of the toothed belt 35a does not occur, and the durability of the toothed belt 35a is improved. Moreover, it can suppress that the neutral information memorize | stored in control part ECU shifts | deviates from the position corresponding to a steering center.

In the above embodiment, the number of the plurality of rubber elastic bodies 53b is four. However, it is not limited to this aspect. The number of rubber elastic bodies 53b may be any number as long as it is three or more.
Moreover, in the said embodiment, although the impact receiving member 53a had the cylinder part 531, it is not restricted to this aspect. The impact receiving member 53a may not have the cylindrical portion 531. As a result, when the four rubber elastic bodies 53b are compressed and deformed in the axial direction and expanded outward in the radial direction around the axis, there is a risk of contact with the outer peripheral surface of the shaft portion 211. The impact absorbing effect can be obtained accordingly.

  In the above embodiment, each of the four rubber elastic bodies 53b includes one convex portion 536 that protrudes radially outward of the shaft portion 211 on each outer peripheral surface. However, the present invention is not limited thereto, and more than two convex portions 536 may be provided on each outer peripheral surface of the rubber elastic body 53b. Further, only one or more convex portions 536 may be provided on the outer peripheral surface of at least one rubber elastic body 53b among the four rubber elastic bodies 53b. Also by this, a sufficient effect according to the present invention can be expected. Furthermore, the convex portion 536 may not be provided, and the effect according to the present invention can be obtained accordingly.

  Moreover, in the said embodiment, the four rubber elastic bodies 53b were each formed so that the cross section orthogonal to an axis line might become circular arc shape. However, the present invention is not limited to this mode, and as in the present invention, it may be formed in a shape such as a prism or cylinder as long as it has a gap around it.

  Moreover, in the said embodiment, the four rubber elastic bodies 53b were set so that the shape rate may include 1.5 and the width | variety of the upper and lower limit value of a shape rate may have the predetermined width | variety (alpha). However, the present invention is not limited to this mode, and the width α of the upper and lower limit values of the shape ratio may not include 1.5. Also by this, the effects according to the present invention can be obtained accordingly.

  DESCRIPTION OF SYMBOLS 10 ... Steering mechanism, 20 ... Steering mechanism, 22 ... Housing, 24 ... Tie rod, 26 ... Steering wheel, 27 ... Ball stud, 50 ... Damper device, 51. .. Large diameter part 51a ... Contact end face (end face) 52 ... Large diameter part housing (housing) 52a ... Large diameter part accommodating part 52b ... Restricting surface 52c -Inner peripheral surface, 52d ... concave portion, 52e ... shaft housing portion, 53 ... shock absorbing member, 53b ... rubber elastic body, 211 ... shaft portion, 213 ... female screw portion, 531 ... Cylinder part, 532 ... Flange part (annular part), 536 ... convex part, D ... interval, S ... electric power steering device (steering device), SF ... free Area, SR ... Pressure receiving area, X ... Compression .

Claims (7)

A shaft having a shaft portion and a large diameter portion;
A housing that is formed in a tubular shape, is inserted through the shaft so as to be relatively movable in the axial direction, and has a regulating surface that faces the end surface of the large-diameter portion in the axial direction;
An impact absorbing member inserted through the shaft portion and interposed between the end surface of the large-diameter portion and the restricting surface;
A damper device comprising:
The shock absorbing member is
An impact receiving member comprising an annular portion capable of contacting the end surface of the large diameter portion;
The annular portion is disposed between the regulating surface side surface and the regulating surface with a gap between each other in the circumferential direction of the shaft portion, and is respectively disposed on the regulating surface side surface of the annular portion. A plurality of rubber elastic bodies to be fixed;
A damper device comprising: The impact receiving member includes a cylindrical portion that opposes the inner peripheral surface of the housing, and the circle that extends radially outward from the cylindrical portion, is opposed to the restriction surface, and can contact the large diameter portion. It has a flange as an annulus,
The plurality of rubber elastic bodies are disposed in a space formed by an inner peripheral surface of the housing, the regulating surface, an outer peripheral surface of the cylindrical portion, and the flange portion,
The plurality of rubber elastic bodies are arranged with a gap between the inner peripheral surface of the housing and the outer peripheral surface of the cylindrical portion when the large diameter portion does not give an impact force to the flange portion. The damper device according to claim 1. The plurality of rubber elastic bodies are pressed in the axial direction by the restriction surface and the flange portion, so as to fill the gap, the inner peripheral surface of the housing, the restriction surface, the outer peripheral surface of the cylindrical portion, and The flange portion is deformed to be in contact with all of the flange portions, and is deformed to be in contact with the rubber elastic body adjacent in the circumferential direction,
The damper device according to claim 2, wherein the impact receiving member is restricted in relative movement with respect to the housing by the deformed rubber elastic body while maintaining a non-contact state with respect to the restriction surface. Each of the plurality of rubber elastic bodies includes a convex portion projecting radially outward of the shaft portion on each outer peripheral surface,
The said housing is provided in the said internal peripheral surface of the said housing with the some recessed part formed corresponding to each said convex part, and accommodating each said convex part. Damper device.   The damper device according to any one of claims 1 to 4, wherein the plurality of rubber elastic bodies are formed in an arc shape and are provided at three or more at equal intervals in a circumferential direction.   The plurality of rubber elastic bodies is an upper limit value of a ratio of a free area that is a surface area of an inner peripheral surface, an outer peripheral surface, and a surface facing the adjacent rubber elastic body, with respect to a pressure receiving area that is a contact area with the annular portion. The damper device according to any one of claims 1 to 5, wherein the lower limit value is set to have a predetermined width including 1.5. A steering device comprising the damper device according to any one of claims 1 to 6,
Both ends are coupled to the steered wheels via tie rods, and are steered shafts that reciprocate in the axial direction to steer the steered wheels, and include the large-diameter portion that is pivotably coupled to the tie rods. The shaft;
The housing that houses the steered shaft;
The shock absorbing member;
A steering apparatus comprising:

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