JP2016097840A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress expansion and shrink of an inner space of a rack boot, during impact absorption time.SOLUTION: A steering device comprises: a rack housing 20 for storing a rack shaft 15; rack ends 17 which are respectively attached to both ends of the rack shaft 15 at outside of the rack housing 20; and an impact absorption member 40 disposed between the rack housing 20 and the rack end 17. The impact absorption member 40 is formed of a cylindrical elastic part 41 and an end damper 42 inserted into inside of the elastic part 41. The end damper 42 is for example, formed of a metal material. A contact surface 42c of the end damper 42 has four grooves 42e as a communication path, with equal intervals in a peripheral direction. Each groove 42e extends over whole length of a radial direction of the contact surface 42c.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering device.

  2. Description of the Related Art Conventionally, there is a steering device that changes the angle of a steered wheel by transmitting rotation of a steering shaft accompanying steering of a steering wheel to a rack and pinion mechanism. The rack and pinion mechanism converts the rotational motion of the steering shaft into linear motion of the rack shaft. A tie rod is rotatably connected to both shaft end portions of the rack shaft via rack ends. The linear movement of the rack shaft is transmitted to the steered wheels via the rack end and the tie rod.

  In a steering apparatus including a rack and pinion mechanism, the rack end abuts against a rack housing that houses the rack shaft, and thus the movement of the rack shaft and, consequently, the steered range of the steered wheels are mechanically restricted. On the other hand, if the angle of the steered wheels changes due to the vehicle climbing on a curb, etc., a strong impact may be applied to the steering system due to the reverse input accompanying the change in the angle of the steered wheels acting on the rack end. There is. Therefore, for example, in the steering device disclosed in Patent Document 1, an elastic body is disposed between the rack end and the rack housing so as to absorb an impact load at the time of so-called end contact where they abut.

Japanese Patent No. 4255632

  According to the steering device disclosed in Patent Document 1, when a strong impact load is applied to an elastic body for absorbing an impact in accordance with end contact, the elastic body is compressed and deformed, whereby the internal space of the housing and the rack There is a possibility that the communication of the internal space of the boot covering the end may be blocked. As the elastic body is compressed, the air in the internal space of the housing is compressed, so the pressure in the internal space of the housing increases, while the air in the internal space of the rack end expands, The pressure decreases.

  An object of the present invention is to suppress the expansion and contraction of the internal space of the boot even during impact absorption.

  A steering device that can achieve the above object is provided with a steered shaft that reciprocates in the axial direction, a housing that houses the steered shaft, and both shaft ends of the steered shaft, respectively. A joint connecting the tie rod and the tie rod; a boot connected between the housing and the tie rod to seal the housing and the tie rod; and the housing and the joint in a moving direction of the steered shaft. And an impact absorbing member that is provided in between and absorbs an impact when they come into contact with each other. The impact absorbing member includes an elastic part having elasticity and an end surface part that is provided between the joint and the elastic part and serves as an end surface on which they abut. When the housing and the joint come into contact with each other via an impact absorbing member, a communication path is formed between the impact absorbing member and the joint to communicate the internal space of the boot and the internal space of the housing. ing.

  According to this structure, even if it is a case where a housing and a joint contact | abut via an impact-absorbing member, the internal space of a boot and the internal space of a housing can be connected by providing a communicating path. When the communication path is not provided, the inner space of the boot and the inner space of the housing are blocked when the housing and the joint come into contact with each other via the impact absorbing member. If an impact load is applied from the state where the housing and the joint are in contact with each other via the shock absorbing member, the elastic portion is deformed and the pressure in the internal space of the boot decreases, and the pressure in the internal space of the housing increases. End up. For this reason, by providing the communication path, it is possible to suppress the pressure in the internal space of the boot from decreasing and the pressure in the internal space of the housing from increasing even when absorbing the impact.

  In the steering apparatus, a groove extending along a radial direction of the end surface portion is provided on a surface of the end surface portion on which the joint abuts, and the housing and the joint abut against each other via the shock absorbing member. In this case, it is preferable that the communication path is formed by the groove and the joint.

  In the steering apparatus, a groove that extends along a radial direction of the contact surface is provided on a contact surface with which the end surface portion of the joint contacts, and the housing and the joint are interposed via the shock absorbing member. The communication path may be formed by the groove and the joint.

  According to these structures, a communicating path is formed by providing a groove | channel in the end surface part of an impact-absorbing member, or the contact surface of a joint. For this reason, even if the housing and the joint are in contact with each other via the shock absorbing member, the internal space of the boot and the internal space of the housing can communicate with each other.

  A steering device that can achieve the above object is provided with a steered shaft that reciprocates in the axial direction, a housing that houses the steered shaft, and both shaft ends of the steered shaft, respectively. And a joint for connecting the steered wheels, and both ends of the steered shaft are provided so as to cover both ends of the steered shaft, one end is connected to the housing, the other end is connected to the joint, and the steered shaft An impact absorbing member that is provided between the housing and the joint in the moving direction and absorbs an impact when they come into contact with each other. The impact absorbing member has an elastic portion having elasticity and an end surface portion provided between the joint and the elastic portion and serving as an end surface with which the elastic member abuts. A groove is provided on the contact surface, and a communication path is formed by the groove and the elastic portion.

  According to this configuration, the communication path is formed by providing the groove on the abutting surface where the housing and the elastic portion abut. For this reason, it can suppress that the internal space of a boot and the internal space of a housing are interrupted | blocked. That is, when an impact load is applied, there is a possibility that the compressed elastic part may enter the communication path provided on the contact surface, but it is possible to communicate until the elastic part enters the communication path. It is possible to suppress the pressure in the internal space of the housing from decreasing and the pressure in the internal space of the housing from increasing.

  In the steering apparatus, the motor includes a motor, a speed reducer that decelerates the rotation of the motor, and a ball screw mechanism that converts the decelerated rotation of the motor into a reciprocating motion of the steered shaft. Further, it may be provided in the vicinity of the impact absorbing member.

  According to this configuration, the ball screw mechanism is provided in the vicinity of the shock absorbing member. When the ball screw mechanism is employed, a seal portion and a sealing structure are provided so that water and foreign matter do not enter the ball screw mechanism from the outside. For this reason, the inner space of the housing is more likely to be sealed, and the effect when the communication path is provided is high.

  According to the steering device of the present invention, expansion and contraction of the internal space of the rack boot can be suppressed even during impact absorption.

The block diagram which shows the structure of an electric power steering apparatus. Sectional drawing which shows schematic structure of the rack end vicinity. (A) is a perspective sectional view of an impact-absorbing member. (B) is a top view of an impact-absorbing member. (A)-(c) is sectional drawing which shows the rack end vicinity at the time of a load effect | action. (A), (b) is sectional drawing which shows the rack end vicinity of other embodiment.

Hereinafter, an embodiment of the steering device will be described. Here, a so-called rack parallel type electric power steering device (RP-EPS) is taken as an example.
As shown in FIG. 1, an electric power steering device (EPS) 1 includes a steering mechanism 2 that steers steered wheels 19 based on an operation of a driver's steering wheel 10, and an assist mechanism 3 that assists the driver's steering operation. It has.

  The steering mechanism 2 includes a steering wheel 10 and a steering shaft 11 that rotates integrally with the steering wheel 10. The steering shaft 11 has a column shaft 12 connected to the steering wheel 10, an intermediate shaft 13 connected to the lower end portion of the column shaft 12, and a pinion shaft 14 connected to the lower end portion of the intermediate shaft 13. ing. The pinion teeth 14a at the lower end of the pinion shaft 14 mesh with a rack shaft 15 (more precisely, the rack teeth 15a) extending in a direction intersecting with the pinion shaft 14. Therefore, the rotational motion of the steering shaft 11 is converted into a reciprocating linear motion in the axial direction of the rack shaft 15 via the rack and pinion mechanism 16 including the pinion shaft 14 and the rack shaft 15. The reciprocating linear motion is transmitted to the tie rods 18 via the rack ends 17 connected to both ends of the rack shaft 15, and the motions of these tie rods 18 are transmitted to the left and right steered wheels 19, respectively. The steering angle changes.

  The assist mechanism 3 is provided on the rack shaft 15. The assist mechanism 3 transmits to the ball screw mechanism 23 the rotational force of the rotating shaft 22a of the motor 22 and the ball screw mechanism 23 integrally attached around the motor 22 and the rack shaft 15 which are assist force generation sources. It consists of a reduction gear 24. The assist mechanism 3 converts the rotational force of the rotating shaft 22a of the motor 22 into a reciprocating linear motion in the axial direction of the rack shaft 15 via the speed reducer 24 and the ball screw mechanism 23 to assist the driver's steering operation.

  The pinion shaft 14, the rack shaft 15, and the assist mechanism 3 are accommodated in the rack housing 20. The rack housing 20 is provided with a speed reducer housing 25 that houses a part of the speed reducer 24. The reduction gear housing 25 protrudes in a direction (downward in the drawing) that intersects the direction in which the rack shaft 15 extends. A flange portion 22 b of the motor 22 is fixed to the outer wall (the right side wall in the figure) of the reduction gear housing 25 by bolts 26. The rotating shaft 22a is disposed so as to be parallel to the direction in which the rack shaft 15 extends. A rotation shaft 22 a of the motor 22 extends into the reduction gear housing 25 through a through hole 27 formed in the reduction gear housing 25.

  The speed reducer 24 includes a drive pulley 24a that is integrally attached to the rotating shaft 22a of the motor 22, a driven pulley 24b that is integrally attached to the outer periphery of the nut 23a of the ball screw mechanism 23, a drive pulley 24a, and a driven pulley. Belt 24c wound around 24b. For example, a toothed belt is employed as the belt 24c.

  At both ends of the rack housing 20, a bellows-shaped rack boot 21 is provided. One end of the rack boot 21 is connected to the end of the rack housing 20, and the other end of the rack boot 21 is connected to the tie rod 18. A portion of the rack end 17 and the tie rod 18 is covered with a corresponding rack boot 21. The rack boot 21 prevents foreign matters such as dust and water from entering the rack housing 20 and the rack end 17.

Next, the configuration of the end portion of the rack shaft 15 will be described. Note that the two end portions have the same configuration, except that the left and right directions are different.
As shown in FIG. 2, a ball joint 30 is employed for the rack end 17 as an example. The ball joint 30 includes a ball stud 31 provided with a ball portion 31a at the tip, and a socket 32 that rotatably accommodates the ball portion 31a. Inside the socket 32, a spherical seat 32a corresponding to the spherical shape of the ball portion 31a is mounted. The ball stud 31 is flexibly connected to the socket 32 by fitting the ball portion 31a to the spherical seat 32a. The end of the ball stud 31 opposite to the ball portion 31 a is fixed to the end of the tie rod 18 opposite to the steered wheel 19, so that the tie rod 18 is connected to the rack shaft 15 so as to be bent.

  The ball joint 30 is fixed to the rack shaft 15 by the socket 32 being screwed into the end of the rack shaft 15. A cylindrical portion 34 that protrudes toward the rack shaft 15 is formed on the end surface 33 of the socket 32 on the rack shaft 15 side. A male screw portion 35 is formed on the outer peripheral surface of the cylindrical portion 34. On the other hand, a circular hole 36 concentric with the rack shaft 15 is provided at the end of the rack shaft 15. A female screw portion 37 corresponding to the male screw portion 35 is formed on the inner peripheral surface of the circular hole 36. The socket 32 is fixed to the end of the rack shaft 15 by the male screw portion 35 being screwed into the female screw portion 37. Note that the end surface 33 of the socket 32 is also the end surface 33 of the ball joint 30.

  An insertion portion 20 a through which the rack shaft 15 is inserted passes through the rack housing 20 in the axial direction X. An end portion of the rack housing 20 is provided with an enlarged diameter portion 20b into which the socket 32 is inserted. The inner diameter of the enlarged diameter portion 20b is set larger than the inner diameter of the insertion portion 20a. The insertion portion 20a and the enlarged diameter portion 20b communicate with each other. A regulation surface 20c orthogonal to the axial direction X is formed at the boundary portion between the insertion portion 20a and the enlarged diameter portion 20b. A fitting portion 20d that is an annular recess is formed on the inner peripheral surface of the end portion on the regulating surface 20c side in the enlarged diameter portion 20b.

  The outer diameter of the socket 32 is set to be larger than the inner diameter of the insertion portion 20a of the rack housing 20 and smaller than the inner diameter of the enlarged diameter portion 20b. For this reason, as the rack shaft 15 moves, so-called end contact occurs in which the end surface 33 comes into contact with the regulating surface 20c. If the impact applied to the end acts on the EPS 1 without any relaxation, for example, the teeth of the belt of the speed reducer 24 may fly. Therefore, an impact absorbing member 40 is provided between the regulating surface 20c of the rack housing 20 and the end surface 33 of the ball joint 30 in order to absorb an impact at the time of end contact.

As shown in FIG. 3A, the impact absorbing member 40 includes a cylindrical elastic portion 41 and an end damper 42 inserted into the elastic portion 41.
The elastic part 41 is made of an elastic material such as rubber or synthetic resin. The elastic part 41 includes a cylindrical main body part 41a and a second end part (upper part in the figure) opposite to the first end part (lower part in the figure) into which the end damper 42 of the main body part 41a is inserted. And a flange-like fitting portion 41b provided on the outer peripheral surface. The outer diameter of the fitting portion 41 b is set to be approximately the same as the inner diameter of the fitting portion 20 d of the rack housing 20. Note that the outer diameter of the main body portion 41 a that is a portion excluding the fitting portion 41 b of the elastic portion 41 is set to be smaller than the enlarged diameter portion 20 b of the rack housing 20. Further, it is preferable that the elastic part 41 has a shock absorption property that does not cause a failure in each part of the EPS 1 even if a constant load set based on the load applied at the time of end application is applied a certain number of times. In this case, the elastic part 41 is ideally used within the range of elastic deformation.

  The end damper 42 is made of, for example, a metal material. The end damper 42 has a cylindrical restricting portion 42b. The inner diameter of the restricting portion 42 b is set to a value larger than the outer diameter of the rack shaft 15, and the outer diameter of the restricting portion 42 b is set to be approximately the same as the inner diameter of the elastic portion 41. For this reason, a gap is formed between the rack shaft 15 and the restricting portion 42b, and air can move through the gap. The length L2 in the axial direction X of the restricting portion 42b of the end damper 42 is set to be shorter than the length L3 of the elastic portion 41. However, the length L3 is the length in the axial direction X of the elastic portion 41 when the load accompanying the end pad is not acting. The restricting portion 42b is inserted into the first end of the elastic portion 41 (more precisely, the fitting portion 41b). The outer peripheral surface of the restricting portion 42b is fitted to the inner peripheral surface of the fitting portion 41b. In the axial direction X of the restricting portion 42b, a flange portion 42a is formed at an end portion on the opposite side to the end portion (upper end portion in the figure) on the side inserted into the fitting portion 41b. The outer diameter of the flange portion 42 a is set smaller than the inner diameter of the enlarged diameter portion 20 b in the rack housing 20. The central axes of the elastic part 41 and the end damper 42 coincide with each other.

  As shown in FIG. 2, the shock absorbing member 40 is inserted into the enlarged diameter portion 20 b from the second end side of the elastic portion 41. Inside the enlarged diameter portion 20b, the rack shaft 15 penetrates the shock absorbing member. The second end portion of the elastic portion 41 is in contact with the regulation surface 20 c of the rack housing 20. Further, the fitting portion 41 b of the elastic portion 41 is fitted to the fitting portion 20 d of the rack housing 20. By fitting the fitting portion 41b into the fitting portion 20d, the shock absorbing member 40 is fixed inside the enlarged diameter portion 20b. Since the outer diameter of the flange portion 42a is set smaller than the inner diameter of the enlarged diameter portion 20b, a gap is formed between the outer peripheral surface of the flange portion 42a and the inner peripheral surface of the enlarged diameter portion 20b. Further, the side surface on the ball joint 30 side of the flange portion 42a of the end damper 42 functions as an abutting surface 42c that abuts on the end surface 33 of the ball joint 30 at the time of end contact.

  As shown in FIG. 3B, precisely, the end surface 33 of the ball joint 30 contacts the contact surface 42c in a region on the inner diameter side of the dotted line 42d depicted on the contact surface 42c. The contact surface 42c is provided with four grooves 42e as communication paths at equal intervals in the circumferential direction. Each groove 42e extends over the entire length in the radial direction of the contact surface 42c. For this reason, the portion provided with the groove 42e in the contact surface 42c does not contact the end surface 33 during end contact. That is, the end surface 33 contacts the contact surface 42c in a state where a groove-like gap is formed between the groove 42e and the end surface 33. Further, at the time of end contact, the elastic portion 41 is compressed in the axial direction X, so that the second end portion of the restricting portion 42 b comes into contact with the restricting surface 20 c of the rack housing 20. For example, a normal load is applied to the ball joint 30 when the steering operation is performed while traveling at a low speed or while slowing down when entering the garage. At this time, the elastic portion 41 is compressed and deformed along the axial direction X, so that the impact at the time of end contact is absorbed. The compression allowance L1 that can be compressed by the elastic portion 41 is defined by the difference between the length L2 of the restricting portion 42b and the length L3 of the elastic portion 41 in the axial direction X. That is, the amount of the elastic portion 41 that can be compressed in the axial direction X is limited by the length of the restricting portion 42b.

Next, a space formed between the members will be described with reference to FIG.
A space S <b> 1 is formed between the inner periphery of the enlarged diameter portion 20 b of the rack housing 20 and the outer periphery of the rack shaft 15, and between the contact surface 42 c of the end damper 42 and the end surface 33 of the ball joint 30. Further, between the inner circumference of the enlarged diameter portion 20b of the rack housing 20 and the outer circumference of the elastic portion 41, and between the fitting portion 41b of the elastic portion 41 and the flange portion 42a of the end damper 42, the entire circumference is provided. A space S2 is formed. Further, between the inner circumference of the elastic portion 41 and the outer circumference of the rack shaft 15, between the regulating surface 20 c of the rack housing 20 and the regulating portion 42 b of the end damper 42, and between the inner circumference of the regulating portion 42 b and the rack shaft 15. A space S3 is formed between the outer periphery. Note that the space S3 and the groove 42e communicate with each other because of a gap formed between the rack shaft 15 and the restricting portion 42b and a screw groove formed on the outer peripheral surface of the rack shaft 15. Further, a space S0 is formed on the rack boot 21 side with the end face 33 as a reference and between the enlarged diameter portion 20b and the socket 32. The space S0 communicates with the space inside the rack boot 21.

Next, the operation of the shock absorbing member 40 at the time of end contact will be described.
As shown in FIG. 4A, when the steering wheel 10 is not steered to the vicinity of the operation limit, the end surface 33 of the ball joint 30 and the contact surface 42c of the end damper 42 are separated from each other. From this state, when a positive input accompanying steering or a reverse input from the steered wheel 19 side is applied to the rack shaft 15, the end surface 33 of the ball joint 30 becomes the regulating surface of the rack housing 20 according to the moving direction of the rack shaft 15. Move in a direction approaching 20c. As the end surface 33 approaches the restriction surface 20c, the space S1 is contracted. Since the end surface 33 is not in contact with the contact surface 42c of the end damper 42, the spaces S2 and S3 do not change.

  As shown in FIG. 4B, when the steering wheel 10 is steered to the vicinity of the operation limit, the end surface 33 of the ball joint 30 contacts the contact surface 42c of the end damper 42. For this reason, the space S1 disappears. When the end surface 33 comes into contact with the contact surface 42c, a large load is not applied to the impact absorbing member 40, so that spaces S2 and S3 exist between the restriction portion 42b and the restriction surface 20c.

  When the rack shaft 15 is further moved from the state in which the end surface 33 is in contact with the contact surface 42c so that the end surface 33 approaches the contact surface 42c, the elastic portion 41 starts to be compressed along with the movement, and the space S2 , S3 are gradually shortened. When the space S3 is contracted, the air inside the space S3 moves to the space S0 through the groove 42e. This point will be described later.

  As shown in FIG. 4C, when the steering wheel 10 is steered to the operation limit, a so-called end contact occurs in which the restricting portion 42b comes into contact with the restricting surface 20c. At this time, in the axial direction X, the elastic portion 41 is compressed between the end surface 33 and the restriction surface 20c so as to be shortened to a length L2 equal to the restriction portion 42b. As a result, the space S3 is contracted and the compression allowance L1 becomes almost zero. The compression margin L1 being substantially zero means a state where the restricting portion 42b is in contact with the restricting surface 20c. Further, as the elastic portion 41 is compressed and deformed along the axial direction X, it is expanded and deformed in a radial direction perpendicular to the axial direction X. The elastic part 41 expands in the form of filling the space S2.

Next, the movement of air in the spaces S1, S2, and S3 accompanying the compression of the elastic portion 41 will be described in detail.
The elastic portion 41 is expanded by filling the space S2 by being compressed between the end surface 33 and the regulating surface 20c and being compressed and deformed in the axial direction X. At this time, as the space S2 is filled with the elastic portion 41, the air originally present in the space S2 moves to the space S0 through the gap between the flange portion 42a and the enlarged diameter portion 20b. For this reason, an increase in the pressure inside the space S2 is suppressed.

  As the elastic portion 41 is compressed, the end damper 42 moves in the axial direction X, and the restricting portion 42b approaches the restricting surface 20c. At this time, as the restricting portion 42b enters the space S3, the air existing in the space S3 moves to the space S0 through the groove 42e. For this reason, an increase in the pressure inside the space S3 is suppressed.

  Further, as the end face 33 approaches the restricting face 20c, the air present in the space S0 expands. At this time, since the air inside the space S3 moves to the space S0 through the groove 42e, a decrease in the pressure inside the space S0 is suppressed. Since the decrease in the pressure inside the space S0 is suppressed, the decrease in the pressure in the inner space of the rack boot 21 is also suppressed.

Incidentally, the provision of the groove 42e improves the bending strength of the end damper 42.
The contact surface 42c of the end damper 42 is in contact with the ball joint 30 in a region on the inner peripheral side from the dotted line 42d shown in FIG. At this time, if the flange portion 42a does not have a certain thickness, buckling may occur at the portion of the dotted line 42d when receiving an impact load, and the flange portion 42a may be bent. However, by providing the groove-like groove 42e, the bending strength of the flange portion 42a when receiving an impact load can be increased.

The effect of this embodiment will be described.
(1) Since the end damper 42 is provided with the groove 42e, the air compressed in the space S3 moves to the space S0 through the groove 42e at the time of end contact. This is because a groove-like gap is formed between the groove 42e and the end surface 33 even when the end surface 33 contacts the contact surface 42c. For this reason, even at the time of end contact, the space S0 and the space S3 communicate with each other through the groove 42e. Therefore, an increase in pressure inside the space S3 can be suppressed. In addition, a decrease in the pressure inside the space S0 can be suppressed, and as a result, a decrease in the pressure in the internal space of the rack boot 21 can be suppressed. Deterioration of the rack boot 21 can be suppressed.

  Further, when the ball screw mechanism 23 is adopted, the inner side of the ball screw mechanism 23 between the rack shaft 15 and the rack housing 20 in the axial direction is prevented from entering water and foreign matter from the outside. A seal part and a sealing structure are provided in the region. For this reason, when the ball screw mechanism 23 is employed, the space S3 is easily sealed, and there is no portion that communicates with the air when it is compressed. Therefore, the effect of providing the groove 42e is high. .

  (2) By providing the groove 42e, the bending strength of the flange portion 42a of the end damper 42 can be increased. For this reason, if the bending strength requested | required is the same, the thickness of the flange part 42a can be made thin compared with the end damper 42 which does not provide the groove | channel 42e. For this reason, the end damper 42 can be further reduced in weight.

In addition, you may change this embodiment as follows. The following other embodiments can be combined with each other within a technically consistent range.
-In this embodiment, fitting part 41b, 20d does not need to be provided. In this case, the elastic portion 41 is preferably fixed to the rack housing 20 using an adhesive or the like.

In the present embodiment, the impact absorbing member 40 may be fixed to the end surface 33 of the ball joint 30.
In the present embodiment, the positional relationship between the elastic portion 41 and the end damper 42 may be as follows. That is, the elastic portion 41 may be provided on the radially inner side of the end damper 42.

  -In this embodiment, although the groove | channel 42e was provided in the end damper 42, as shown to Fig.5 (a), you may provide the groove | channel 33a in the end surface 33 of the ball joint 30. FIG. Moreover, as shown in FIG.5 (b), you may provide the groove | channel 20e mutually connected to the inner surface of the diameter expansion part 20b of a rack housing, and the control surface 20c, respectively. For example, when the groove 20e is provided, the elastic part 41 may be pinched between the end surface 33 and the regulating surface 20c, so that the elastic part 41 may expand and block the groove 20e. However, since the space S0 and the space S3 can be communicated until the elastic portion 41 expands and closes the groove 20e, an increase in the pressure in the space S3 can be suppressed, and the pressure in the space S0 and the internal space of the rack boot 21 can be suppressed. Can be suppressed.

  In the present embodiment, four grooves 42e are provided in the end damper 42, but the number is not limited to four. For example, five or more may be provided, and fewer than four may be provided. Further, the shape of the communication path is not limited to the groove shape, and may be a hole penetrating in the radial direction of the flange portion 42a, for example, when the thickness of the flange portion 42a can be sufficiently secured.

  In the present embodiment, the end damper 42 is a member in which the flange portion 42a and the restricting portion 42b are integrated, but these may be separate members. Moreover, although the outer diameter of the flange part 42a was set smaller than the internal diameter of the enlarged diameter part 20b, you may set substantially equal. In this case, in order to suppress the space S2 from being compressed and increasing the pressure inside the space S2, it is preferable that the space S2 is set to have almost no space.

  -In this embodiment, although the electric power steering device was mentioned as an example as a steering device, you may apply to a steer-by-wire (SBW). In addition, when it materializes to a steer-by-wire, it can also materialize not only as a front-wheel steering apparatus but as a rear-wheel steering apparatus or a 4-wheel steering apparatus (4WS).

  -In this embodiment, although concretely shown to RP-EPS, it is not restricted to this. For example, a column assist type EPS or a rack assist type EPS may be used.

  DESCRIPTION OF SYMBOLS 1 ... EPS, 2 ... Steering mechanism, 3 ... Assist mechanism, 10 ... Steering wheel, 11 ... Steering shaft, 12 ... Column shaft, 13 ... Intermediate shaft, 14 ... Pinion shaft, 15 ... Rack shaft (steering shaft), DESCRIPTION OF SYMBOLS 16 ... Rack and pinion mechanism, 17 ... Rack end (joint), 18 ... Tie rod, 19 ... Steered wheel, 20 ... Rack housing (housing), 20a ... Insertion part, 20b ... Diameter expansion part, 20c ... Restriction surface, 20d ... Fitting portion, 20e ... groove (communication path), 21 ... rack boot (boot), 22 ... motor, 22a ... rotating shaft, 23 ... ball screw mechanism, 24 ... speed reducer, 25 ... speed reducer housing, 26 ... bolt, 27 ... Through hole, 30 ... Ball joint (joint), 31 ... Ball stud, 31a ... Ball part 32 ... Socket, 32a ... Spherical seat, 33 ... End face, 33a ... Groove (communication path), 34 ... Cylindrical part, 35 ... Male screw part, 36 ... Circular hole, 37 ... Female screw part, 40 ... Shock absorbing member, 41 ... Elasticity Part 41a ... body part 41b fitting part 42 end damper (end face part) 42a flange part 42b regulating part 42c contact surface 42d dotted line 42e groove (communication path)

Claims (5)

A steering shaft that reciprocates in the axial direction;
A housing that houses the steered shaft;
A joint that is attached to both ends of the steered shaft and connects the steered shaft and the tie rod;
A boot connected between the housing and the tie rod to seal the housing and the tie rod;
An impact absorbing member that is provided between the housing and the joint in the direction of movement of the steered shaft and absorbs an impact when they abut,
The shock absorbing member has an elastic part having elasticity, and an end surface part which is provided between the joint and the elastic part and serves as an end surface on which they abut,
When the housing and the joint come into contact with each other via an impact absorbing member, a communication path is formed between the impact absorbing member and the joint to communicate the internal space of the boot and the internal space of the housing. Steering device. The steering apparatus according to claim 1, wherein
A groove extending along a radial direction of the end surface portion is provided on a surface of the end surface portion on which the joint abuts.
When the housing and the joint abut through the shock absorbing member,
A steering device in which the communication path is formed by the groove and the joint. The steering apparatus according to claim 1, wherein
A groove extending along a radial direction of the contact surface is provided on the contact surface with which the end surface portion of the joint contacts.
When the housing and the joint abut through the shock absorbing member,
A steering device in which the communication path is formed by the groove and the joint. A steering shaft that reciprocates in the axial direction;
A housing that houses the steered shaft;
A joint that is attached to both ends of the steered shaft and connects the steered shaft and the tie rod;
A boot connected between the housing and the tie rod to seal the housing and the tie rod;
An impact absorbing member that is provided between the housing and the joint in the direction of movement of the steered shaft and absorbs an impact when they abut,
The shock absorbing member has an elastic part having elasticity, and an end surface part which is provided between the joint and the elastic part and serves as an end surface on which they abut,
A steering device in which a groove is provided on a contact surface with which the elastic portion of the housing contacts, and a communication path is formed by the groove and the elastic portion. In the steering device according to any one of claims 1 to 4,
A motor,
A decelerator that decelerates the rotation of the motor;
A ball screw mechanism that converts the reduced speed rotation of the motor into a reciprocating motion of the steered shaft;
The ball screw mechanism is a steering device provided in the vicinity of the shock absorbing member.