JP2012148740A - Steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering system capable of suppressing transmission of external force applied to a steered wheel to a steering shaft.SOLUTION: The steering system includes a rack shaft 20 for operating the steered wheel, a pinion shaft moving on the rack shaft 20, a support mechanism for rollingly bearing the rack shaft 20, and a rack housing 30 for storing the rack shaft 20. A friction imparting mechanism 50 imparting friction resistance to the rack shaft 20 and adjusting the size of the friction resistance is arranged between the rack housing 30 and the rack shaft 20.

Description

  The present invention relates to a steering apparatus including a rack shaft for operating a steered wheel, a pinion shaft for driving the rack shaft, a support mechanism for rolling and supporting the rack shaft on the pinion shaft, and a rack housing for accommodating the rack shaft. About.

  In the steering device, a support mechanism that meshes and supports the rack shaft and the pinion shaft in an optimum state is provided at a portion where the rack shaft and the pinion shaft mesh. As an example of the support mechanism, one described in Patent Document 1 is known. In the steering apparatus of the same document, a roller that rotates on the back side of the rack shaft is provided, and the rack shaft is rolled and supported by this roller. Thereby, the rotation of the rack shaft in the circumferential direction is restricted.

JP 2004-75000 A

  By the way, a large external force is applied to the rack shaft through the steered wheel, for example, when the steered wheel gets over an obstacle. An external force applied to the rack shaft is transmitted to the steering shaft through the pinion shaft, and a part of the force transmitted to the rack shaft is dispersed to the outside through the support mechanism.

  However, in the support mechanism that supports the rack shaft with a roller as in Patent Document 1, when the contact portion between the roller and the rack shaft is in line contact and the contact area is small, the back surface of the rack shaft is supported by surface contact. The impact transmitted to the steering shaft is greater than that of the support mechanism.

  This invention is made | formed in view of such a situation, The objective is to provide the steering apparatus which can suppress that the external force applied to a steered wheel is transmitted to a steering shaft.

In the following, means for achieving the above object and its effects are described.
(1) The invention according to claim 1 is a rack shaft for operating steered wheels, a pinion shaft for driving the rack shaft, a support mechanism for rolling and supporting the rack shaft, and a rack housing for housing the rack shaft. And a rubbing mechanism that provides a frictional resistance to the rack shaft and adjusts the magnitude of the frictional resistance between the rack housing and the rack shaft. It is said.

  According to the present invention, the friction resistance is applied to the rack shaft by the friction applying mechanism. And the magnitude | size of this frictional resistance is adjusted with this friction provision mechanism. For this reason, it can suppress that external force is transmitted to a steering shaft, without providing excessive frictional resistance to a rack axis | shaft.

  (2) The invention according to claim 2 is the steering apparatus according to claim 1, wherein the friction applying mechanism is provided in the rack housing and an elastic member that applies the friction resistance to the rack shaft. The gist of the present invention is to include an accommodating portion for accommodating the elastic member and an adjusting mechanism for adjusting the magnitude of the frictional resistance.

  According to this invention, when an external force is applied to the steered wheels, the external force transmitted to the rack shaft is received by the elastic member, so that the external force is reduced. Thereby, damage to the rack housing or the pinion shaft due to external force can be reduced.

  (3) The invention according to claim 3 is the steering apparatus according to claim 2, wherein the elastic member is a cylindrical body having an insertion hole into which the rack shaft is inserted. A slit is provided along the axial direction of the cylindrical body, an outer peripheral surface is formed in a tapered shape, and an external thread is formed on the outer peripheral surface. The housing portion has an inner peripheral surface formed in a tapered shape. In addition, a female screw is formed on the inner peripheral surface, and the gist is that the adjusting mechanism includes a male screw of the elastic member and a female screw of the housing portion.

  According to this invention, it is possible to adjust the size of the diameter of the insertion hole of the elastic member by adjusting the slit width according to the degree of screwing the elastic member into the accommodating portion. Thereby, the magnitude of the frictional resistance applied to the rack shaft can be easily adjusted.

  (4) The invention according to claim 4 is the steering apparatus according to claim 2, wherein the elastic member is a cylindrical body having an insertion hole into which the rack shaft is inserted, and an outer peripheral surface is formed in a tapered shape. The accommodating portion has an inner peripheral surface formed in a taper shape, and the adjustment mechanism includes a pressing spring that presses the elastic member in the axial direction in a state where the elastic member is inserted into the accommodating portion, The gist is to include a nut that compresses the pressing spring.

  According to this invention, the magnitude | size of the diameter of the insertion hole of an elastic member can be changed by adjusting the degree which presses an elastic member with the compression amount of a press spring. Thereby, the magnitude of the frictional resistance applied to the rack shaft can be easily adjusted.

  (5) The invention according to claim 5 is the steering apparatus according to claim 2, wherein the elastic member is a ring body, and an inner peripheral portion of the ring body provides a frictional resistance to the rack shaft. The gist is that the adjusting mechanism is a nut that crushes the ring body to adjust the size of the inner peripheral portion.

  According to the present invention, it is possible to change the size of the inner diameter of the ring body by adjusting the degree of deformation of the ring body by the amount of movement of the nut. Thereby, the magnitude of the frictional resistance applied to the rack shaft can be easily adjusted.

  (6) The invention according to claim 6 is the steering apparatus according to claim 2, wherein the elastic member is an O-ring, and an inner peripheral portion of the O-ring gives a frictional resistance to the rack shaft. The gist is that the accommodating portion is formed as a groove into which the elastic member is fitted.

  According to the present invention, since the portion into which the O-ring is fitted is formed as a groove, the position of the O-ring is defined even if the O-ring is not fixed to the rack housing by the nut. Thereby, the number of components of the friction applying mechanism can be reduced.

(7) The gist of the invention described in claim 7 is that the steering apparatus according to any one of claims 2 to 6 includes a lock nut for restricting looseness of the adjusting mechanism.
It is assumed that the use of the steering device for many years causes the adjustment mechanism to loosen and the elastic member to deviate from the fixed position of the rack housing, thereby creating a gap between the rack shaft and the insertion hole of the elastic member. In this case, the frictional resistance between the rack shaft and the elastic member is reduced. In this respect, according to the above-described invention, since the loosening of the adjusting mechanism is limited by the lock nut, it is possible to suppress a decrease in frictional resistance.

  (8) According to an eighth aspect of the present invention, in the steering apparatus according to any one of the first to seventh aspects, the friction applying mechanism is provided at an end of the rack housing. Yes.

  According to the present invention, since the friction applying mechanism is provided at the end of the rack housing, the friction applying mechanism can be easily provided as compared with the structure in which the friction applying mechanism is provided in the intermediate portion of the rack housing. it can. In addition, the frictional resistance can be adjusted even after being mounted on the vehicle, and the frictional resistance can be finely adjusted with respect to the external force actually acting on the vehicle. It can be relaxed with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the steering apparatus which can suppress that the external force applied to a steered wheel is transmitted to a steering shaft can be provided.

The schematic diagram which shows typically the whole structure about the steering apparatus of 1st Embodiment of this invention. About the steering apparatus of the embodiment, a cross-sectional structure of a cross section along line AA in FIG. 1 is shown, (A) is a cross-sectional view showing one end, and (B) is a cross-sectional view showing the other end. . Sectional drawing which shows the cross-section of the cross section along the BB line of FIG. 1 about the steering apparatus of the embodiment. Sectional drawing which shows the cross-section of the edge part of a rack housing about the steering apparatus of the embodiment. About the steering apparatus of the embodiment, the elastic member is shown, (A) is a perspective view which shows a perspective structure, (B) is a side view which shows a side structure. Sectional drawing which shows the cross-section of the edge part of a rack housing about the steering apparatus of 2nd Embodiment of this invention. About the steering apparatus of the embodiment, the elastic member is shown, (A) is a perspective view which shows a perspective structure, (B) is a side view which shows a side structure. Sectional drawing which shows the cross-section of the edge part of a rack housing about the steering apparatus of 3rd Embodiment of this invention.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
With reference to FIG. 1, the whole structure of the steering apparatus 1 is demonstrated.

The steering angle transmission mechanism 2 of the steering device 1 is provided with an EPS actuator 3 for assisting the steering operation.
The EPS actuator 3 includes a motor 4 that applies torque to the motor output shaft, and a speed reduction mechanism 5 that decelerates the rotation of the motor output shaft and transmits it to the pinion shaft 10. The pinion shaft 10 is connected to the steering via a torsion bar and a steering shaft. That is, the pinion shaft 10 rotates by the torque by the steering and the torque by the motor 4.

The steering angle transmission mechanism 2 will be described with reference to FIG.
The steering angle transmission mechanism 2 rolls the pinion shaft 10, the rack shaft 20 that operates the tie rod by converting the rotation of the pinion shaft 10 into a linear motion, the rack housing 30 that houses the rack shaft 20, and the rack shaft 20. A support mechanism 40 for supporting and a friction applying mechanism 50 for applying a frictional resistance to the rack shaft 20 are provided. A configuration including the rack shaft 20, the pinion shaft 10, and the support mechanism 40 is referred to as a rack and pinion mechanism.

  The rack housing 30 is provided with a through hole 34 that accommodates the rack shaft 20 so as to be movable in the axial direction. Three iron bushes for guiding the rack shaft 20 are provided on the inner periphery of the rack housing 30.

  The first bush 31 is provided at one end 30 </ b> A of the rack housing 30. The second bush 32 is provided at a predetermined distance from one end 30 </ b> A of the rack housing 30. The third bush 33 is provided at the other end 30 </ b> B of the rack housing 30.

  The first bush 31, the second bush 32, and the third bush 33 support the rack shaft 20 so as not to bend when it is applied with a force in the radial direction of the rack shaft 20. Further, the inner peripheral surfaces of the first bush 31, the second bush 32, and the third bush 33 are subjected to surface processing so as to reduce the frictional resistance so as not to inhibit the movement of the rack shaft 20.

  A pinion accommodating portion 35 that accommodates the pinion shaft 10 is provided between the portion where the first bush 31 is provided and the portion where the second bush 32 is provided. A support housing portion 36 is provided on the opposite side of the rack shaft 20 from the pinion housing portion 35. A support mechanism 40 is provided in the support accommodating portion 36. A friction imparting accommodating portion 51 (accommodating portion) as a component of the friction imparting mechanism 50 is provided inside the other end 30 </ b> B of the rack housing 30. In addition, the friction provision housing part 51 includes a space surrounded by the inner peripheral wall and the inner peripheral wall of the rack housing 30 in a portion where the friction applying mechanism 50 is provided.

Next, the rack shaft 20 will be described.
Both end portions of the rack shaft 20 protrude from both ends of the rack housing 30. Each end portion of the rack shaft 20 is provided with a connection portion 24 for providing a tie rod. A tooth portion 26 that meshes with the pinion shaft 10 is provided at a predetermined distance from one end portion 20 </ b> A of the rack shaft 20. A support portion 25 is provided on the opposite side of the portion where the tooth portion 26 is provided. The support portion 25 is formed as a surface that is parallel to the axial direction of the rack shaft 20 and is perpendicular to the direction in which the pinion shaft 10 and the rack shaft 20 are in contact with each other.

  In the rack shaft 20, a first contact portion 21 that contacts the first bush 31 is provided at a predetermined distance from one end portion 20 </ b> A. A second contact portion 22 that contacts the second bush 32 is provided at a predetermined distance from the tooth portion 26. A third contact portion 23 that contacts the third bush 33 is provided at a predetermined distance from the other end portion 20B. That is, the rack shaft 20 is supported by the pinion shaft 10, the first bush 31, the second bush 32, and the third bush 33.

  The rack shaft 20 operates as follows. When the steering is operated, the pinion shaft 10 rotates together with the steering shaft. The rotation of the pinion shaft 10 is converted into a linear motion of the rack shaft 20 by a rack and pinion mechanism. The linear motion of the rack shaft 20 is transmitted to the knuckle through tie rods connected to both ends of the rack shaft 20. The steering angle of the steered wheels is changed by the operation of the knuckle.

The support mechanism 40 will be described with reference to FIG.
The support mechanism 40 includes a roller 41 that rolls and supports the support portion 25 of the rack shaft 20, and a roller support shaft 42 that rotatably supports the roller 41. The roller support shaft 42 is provided between two bearings 43 that protrude from the rack housing 30. A space between the two bearings 43 corresponds to the support accommodating portion 36. The roller support shaft 42 is provided perpendicular to the axial direction of the rack shaft 20. The side surface of the roller 41 is in contact with the support portion 25.

  The operation of the roller 41 will be described. When the rack shaft 20 moves in the axial direction by the rotation of the pinion shaft 10, a force that moves the coaxial 20 in the axial direction and a force that rotates the coaxial 20 in the circumferential direction act on the rack shaft 20. When the rack shaft 20 rotates in the circumferential direction, the tie rod cannot be properly operated. For this reason, the roller 41 supports the rack shaft 20 so as not to rotate in the circumferential direction. Thereby, the rotation of the rack shaft 20 is restricted.

The friction imparting mechanism 50 will be described with reference to FIG.
The friction applying mechanism 50 includes an elastic member 60 that applies a frictional resistance to the rack shaft 20, a lock nut 54 that fixes the elastic member 60, and the friction applying housing portion 51. The friction imparting accommodating portion 51 includes a first accommodating portion 52 into which the elastic member 60 is fitted and a second accommodating portion 53 into which the lock nut 54 is fitted.

  The first accommodating portion 52 is formed so that the elastic member 60 is fitted between the rack shaft 20 and the rack housing 30. The inner peripheral surface of the first accommodating portion 52 is formed as a tapered surface that narrows in the back direction. An internal thread is formed on the inner peripheral surface. The inner diameter of the second accommodating portion 53 is the same as the outer diameter of the first accommodating portion 52, and a female screw is formed on the inner peripheral surface thereof.

  The elastic member 60 is a cylindrical body having an insertion hole 67 for inserting the rack shaft 20. The outer peripheral surface 66 is formed into a tapered surface so as to follow the tapered surface of the first housing portion 52. A male screw that meshes with the female screw of the first housing portion 52 is formed on the outer peripheral surface 66. The elastic member 60 is screwed into the first housing portion 52 and fixed so that the frictional resistance between the inner peripheral surface 65 and the rack shaft 20 is a value within a predetermined range.

  The lock nut 54 is screwed into the second housing portion 53 and presses the elastic member 60. As a result, the elastic member 60 is prevented from rotating outside in the direction opposite to the screwing direction, and the frictional resistance between the inner peripheral surface 65 of the elastic member 60 and the rack shaft 20 takes a value within a certain range. To maintain.

  The elastic member 60 will be described in more detail with reference to FIG. In the following description, in the elastic member 60, an end portion having a small diameter is referred to as a front end portion 63, and an end portion having a large diameter is referred to as a rear end portion 64. The illustration of the external thread formed on the outer peripheral surface 66 is omitted.

  The elastic member 60 is formed of a resin having a predetermined elastic modulus and a predetermined hardness. Further, since the elastic member 60 is worn by contact with the rack shaft 20, a resin having wear resistance is employed.

  The inner peripheral surface 65 of the elastic member 60 is surface-treated so as to give a frictional resistance to the rack shaft 20. The frictional resistance between the inner peripheral surface 65 and the rack shaft 20 is between the first bush 31 and the rack shaft 20, between the second bush 32 and the rack shaft 20, and between the third bush 33 and the rack shaft 20. Greater than any frictional resistance in between.

  A slit is provided in the peripheral wall 61 of the elastic member 60. The slit penetrates the peripheral wall 61 in the radial direction of the elastic member 60. As the slit, there are a first slit 62 </ b> A extending from the front end portion 63 toward the rear end portion 64 and a second slit 62 </ b> B extending from the rear end portion 64 toward the front end portion 63. The first slits 62A and the second slits 62B are alternately arranged at a predetermined interval in the circumferential direction. Due to such a structure, when the elastic member 60 is screwed into the first accommodating portion 52, the inner diameter of the insertion hole 67 is uniformly reduced.

The operation between the elastic member 60 and the rack shaft 20 will be described.
Since the elastic member 60 has the outer peripheral surface 66 formed in the taper surface, the peripheral wall 61 is pushed inward by screwing the elastic member 60 into the first accommodating portion 52, and the inner diameter of the insertion hole 67. Becomes smaller. The size of the inner diameter is changed by adjusting the screwing degree of the elastic member 60. When the frictional resistance between the inner peripheral surface 65 of the elastic member 60 and the rack shaft 20 is increased, the screwing degree of the elastic member 60 is increased. That is, the structure constituted by the male screw of the elastic member 60 and the female screw of the first housing portion 52 functions as the adjusting mechanism 110 that adjusts the magnitude of the frictional resistance between the inner peripheral surface 65 of the elastic member 60 and the rack shaft 20. To do.

  The operation of the friction applying mechanism 50 will be described. When the pinion shaft 10 is rotated by the steering operation, the rack shaft 20 moves in the axial direction. At this time, a frictional force is generated in a direction opposite to the moving direction of the rack shaft 20 due to the frictional resistance between the rack shaft 20 and the inner peripheral surface 65 of the elastic member 60. This frictional force is set so as not to be a burden on the steering operator by adjusting the degree of screwing of the elastic member 60 into the first housing portion 52. For this reason, the rack shaft 20 moves smoothly in the axial direction.

  On the other hand, when an impact (external force) is applied from the outside such as when the steered wheel collides with a block or the like, the impact is transmitted to the rack shaft 20 via the tie rod and the knuckle. A part of the impact applied to the rack shaft 20 is absorbed by the elastic member 60 of the friction applying mechanism 50 or transmitted to the rack housing 30 via the elastic member 60. For this reason, the magnitude of the impact force transmitted to the pinion shaft 10 via the rack shaft 20 is smaller than that without the friction applying mechanism 50. Thus, the impact transmitted to the steering via the pinion shaft 10 is suppressed by the action of the friction applying mechanism 50.

According to this embodiment, the following effects can be obtained.
(1) In the present embodiment, the friction applying mechanism 50 is provided between the rack housing 30 and the rack shaft 20. The friction applying mechanism 50 applies a frictional resistance to the rack shaft 20. Further, the frictional resistance is adjusted to an appropriate level by the adjusting mechanism 110. For this reason, it is possible to suppress the external force from being transmitted to the steering shaft without imparting excessive frictional resistance to the rack shaft 20.

  (2) In the present embodiment, the friction applying mechanism 50 is provided with an elastic member 60 that applies frictional resistance to the rack shaft 20, and a first storage portion 52 (storage portion) that is provided in the rack housing 30 and stores the elastic member 60. And an adjusting mechanism 110 for adjusting the magnitude of the frictional resistance.

  According to this configuration, when an external force is applied to the steered wheels, the external force transmitted to the rack shaft 20 is received by the elastic member 60, so that the external force is reduced. Thereby, damage to the rack housing 30 or the pinion shaft 10 due to external force can be reduced.

  (3) In the present embodiment, the elastic member 60 is a cylindrical body having an insertion hole 67 into which the rack shaft 20 is inserted, and a first slit 62A and a second slit 62B are provided on the peripheral wall 61 of this cylindrical body. ing. The outer peripheral surface 66 is formed in a tapered shape, and a male screw is formed on the same surface. On the other hand, the inner peripheral surface of the first accommodating portion 52 is formed in a taper shape, and a female screw is formed on the inner peripheral surface. The adjusting mechanism 110 that adjusts the frictional resistance applied to the rack shaft 20 includes a male screw of the elastic member 60 and a female screw of the first housing portion 52.

  According to this configuration, the diameter of the insertion hole 67 of the elastic member 60 is adjusted by adjusting the width of the first slit 62A and the width of the second slit 62B according to the degree of screwing the elastic member 60 into the first housing portion 52. Can be adjusted. Thereby, the magnitude | size of the frictional resistance provided to the rack shaft 20 can be adjusted easily.

  (4) In the present embodiment, the lock nut 54 that restricts the looseness of the adjustment mechanism 110 is provided. When the steering device 1 is used longer, it is assumed that the elastic member 60 is displaced from the fixed position of the rack housing 30 and a gap is generated between the rack shaft 20 and the insertion hole 67 of the elastic member 60. In this case, the frictional resistance between the rack shaft 20 and the elastic member 60 is reduced. In this regard, according to the above-described configuration, the degree of screwing of the elastic member 60 into the first housing portion 52 is limited in order to limit the looseness of the adjustment mechanism 110 by the lock nut 54, that is, by pressing the elastic member 60 with the lock nut 54. Since it is made not to change, the fall of frictional resistance can be controlled.

  (5) In the present embodiment, the friction applying mechanism 50 is provided at the other end 30 </ b> B of the rack housing 30. According to this configuration, the friction applying mechanism 50 can be easily provided as compared with the structure in which the friction applying mechanism 50 is provided in the intermediate portion of the rack housing 30. Further, the frictional resistance can be adjusted even after the friction applying mechanism 50 is assembled to the rack housing 30. In addition, the frictional resistance can be adjusted even after being mounted on the vehicle, and the frictional resistance can be finely adjusted with respect to the external force actually acting on the vehicle. It can be relaxed with high accuracy.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.
The steering device 1 of the present embodiment is obtained by adding the following changes to the configuration of the first embodiment. That is, in the first embodiment, the elastic member 60 is screwed into the first housing portion 52, but instead of such a structure, the elastic member 71 is pressed by a spring. Hereinafter, a detailed change from the configuration of the first embodiment that occurs with this change will be described. In addition, about the structure which is common in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

The friction applying mechanism 70 will be described with reference to FIG.
The friction applying mechanism 70 includes an elastic member 71 that applies frictional resistance to the rack shaft 20, a pressing spring 72 that presses the elastic member 71, a compression nut 73 that compresses the pressing spring 72, and a lock nut that fixes the compression nut 73. 74, and an elastic member 71, a pressing spring 72, a compression nut 73, and a friction applying housing portion 80 that houses the lock nut 74.

  The friction applying housing portion 80 includes an elastic housing portion 81 into which the elastic member 71 is fitted, a spring housing portion 82 that houses the pressing spring 72, a compression nut housing portion 83 into which the compression nut 73 is fitted, and a lock nut 74. And a lock nut housing portion 84 to be fitted.

  The elastic accommodating portion 81 is formed so that the elastic member 71 is fitted between the rack shaft 20 and the rack housing 30. The inner peripheral surface of the friction imparting housing portion 80 is formed as a tapered surface that narrows in the back direction. It differs from the 1st accommodating part 52 of 1st Embodiment by the point by which the internal thread is not formed in the taper surface.

  The spring accommodating portion 82 has an inner diameter that is the same as the outer diameter of the elastic accommodating portion 81. The compression nut housing portion 83 has an inner diameter that is the same as the outer diameter of the spring housing portion 82, and a female screw is formed on the inner peripheral surface thereof. The lock nut accommodating portion 84 has an inner diameter that is the same as the outer diameter of the compression nut accommodating portion 83, and has an internal thread formed on the inner peripheral surface thereof.

  The elastic member 71 is a cylindrical body having an insertion hole 75 into which the rack shaft 20 is inserted. The outer peripheral surface 76 is formed on the tapered surface so as to follow the tapered surface of the elastic accommodating portion 81. The pressing spring 72 is configured by a coil spring. The pressing spring 72 is disposed in contact with the rear end surface 77 of the elastic member 71 and is compressed by a compression nut 73.

  The compression nut 73 is screwed into the compression nut housing 83 to compress the compression spring. By adjusting the screwing degree of the compression nut 73, the compression degree of the compression spring is changed, and the force pushing the elastic member 71 is changed.

  The lock nut 74 is screwed into the lock nut housing portion 84 and presses the compression nut 73. As a result, the compression nut 73 is prevented from rotating outside in the direction opposite to the screwing direction, and the pressing force of the pressing spring 72 against the elastic member 71 is reduced, and between the elastic member 71 and the rack shaft 20. Suppressing a decrease in the frictional resistance.

  The shape of the elastic member 71 will be described with reference to FIG. The material forming the elastic member 71 is the same as that of the elastic member of the first embodiment. One slit 78 is provided on the peripheral wall of the elastic member 71. The slit 78 penetrates the peripheral wall in the radial direction of the elastic member 71 and is formed from the front end portion to the rear end portion. That is, when the elastic member 71 is pushed into the elastic accommodating portion 81, the inner diameter is reduced.

The operation between the elastic member 71 and the rack shaft 20 will be described.
Since the elastic member 71 has an outer peripheral surface 76 formed in a tapered shape, by pushing the elastic member 71 into the inner side of the elastic accommodating portion 81, the peripheral wall is pushed inward, and the inner diameter of the insertion hole 75 is increased. Get smaller. The size of the inner diameter of the insertion hole 75 is changed by adjusting the magnitude of the pressure for pushing the elastic member 71 into the elastic accommodating portion 81. The pushing pressure is changed according to the degree of compression of the pressing spring 72. The degree of compression of the pressing spring 72 can be changed by the degree of screwing of the compression nut 73. When increasing the frictional resistance between the inner peripheral surface 75A of the elastic member 71 and the rack shaft 20, the degree of screwing of the compression nut 73 is increased. The structure of the pressing spring 72 and the compression nut 73 functions as an adjustment mechanism 111 that adjusts the magnitude of the frictional resistance between the inner peripheral surface 75A of the elastic member 71 and the rack shaft 20.

  The action of the friction applying mechanism 70, that is, the force acting between the rack shaft 20 and the elastic member 71 when an impact is applied to the steered wheels and the transmission mode of the force are the same as in the first embodiment. is there.

According to the steering device 1 of the present embodiment, in addition to the effects of the first embodiment (excluding the effect of (3) above), the following effects can be further achieved.
(6) In the present embodiment, the elastic member 71 is a cylindrical body having an insertion hole 75 into which the rack shaft 20 is inserted, and the outer peripheral surface 76 of the elastic member 71 is tapered. On the other hand, the elastic housing portion 81 (housing portion) has an inner peripheral surface formed in a tapered shape. The adjustment mechanism 111 includes a pressing spring 72 that presses the elastic member 71 in the axial direction in a state where the elastic member 71 is inserted into the elastic accommodating portion 81 (accommodating portion), and a compression nut 73 that compresses the pressing spring 72. It is structured as a thing.

  According to this configuration, the size of the inner diameter of the insertion hole 75 of the elastic member 71 can be changed by adjusting the degree to which the elastic member 71 is pressed by the compression amount of the pressing spring 72. Thereby, the magnitude | size of the frictional resistance provided to the rack shaft 20 can be adjusted easily.

  By the way, the size of the rack housing 30 changes due to thermal expansion as the temperature rises. For this reason, when the temperature rises, a gap is generated between the elastic member 71 and the elastic accommodating portion 81 and the inner diameter of the insertion hole 75 is enlarged. As a result, the pressing force between the elastic member 71 and the rack shaft 20 decreases, and as a result, the frictional resistance between the elastic member 71 and the rack shaft 20 decreases.

  On the other hand, the pressing spring 72 presses the elastic member 71 in the axial direction regardless of the temperature change. For this reason, when the dimension of the elastic accommodating part 81 becomes large by temperature rise, the press spring 72 suppresses pushing the elastic member 71 to an axial direction, and suppresses that the internal diameter of the insertion hole 75 of the elastic member 71 becomes large. As a result, the pressing force between the elastic member 71 and the rack shaft 20 and the frictional resistance between the elastic member 71 and the rack shaft 20 are suppressed from decreasing due to the temperature rise.

  Further, according to the structure in which the elastic member 71 is pressed by the pressing spring 72, the following effects are also achieved. That is, as long as the rear end surface 77 and the pressing spring 72 are in contact with each other, a pressing force is applied to the elastic member 71 by the pressing spring 72. When the inner peripheral surface 75A is worn away by friction between the inner peripheral surface 75A of the elastic member 71 and the rack shaft 20, and the inner diameter of the insertion hole 75 is increased, the pressing spring 72 pushes the elastic member 71 to the back. The formation of a gap between the inner peripheral surface 75A of the elastic member 71 and the rack shaft 20 is suppressed. Thereby, friction resistance can be provided to the rack shaft 20 for many years.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG.
The steering device 1 of the present embodiment is obtained by adding the following changes to the configuration of the first embodiment. That is, in the first embodiment, a cylindrical elastic member 60 having a tapered surface is used as a member that imparts friction to the rack shaft 20, but an O-ring (ring body) is used instead of such a structure. It has a structure that imparts friction. Hereinafter, a detailed change from the configuration of the first embodiment that occurs with this change will be described. In addition, about the structure which is common in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The friction applying mechanism 90 includes an elastic member 91 that applies frictional resistance to the rack shaft 20, a first nut 92 that presses the elastic member 91, a second nut 93 that fixes the first nut 92, a first nut 92, And a friction applying housing portion 100 for housing the second nut 93.

  The friction applying housing portion 100 includes an elastic housing portion 101 (housing portion) in which the elastic member 91 is fitted, a first nut housing portion 102 in which the first nut 92 is fitted, and a second nut housing in which the second nut 93 is fitted. Part 103.

  The elastic accommodating portion 101 is formed such that an elastic member 91 is fitted between the rack shaft 20 and the rack housing 30. That is, the elastic accommodating portion 101 is formed as a step portion having an inner diameter that is the same as the outer diameter of the elastic member 91. The inner peripheral surface of the step portion is different from the first accommodating portion 52 of the first embodiment in that it is formed in a plane parallel to the axial direction of the rack shaft 20, that is, it is not formed as a tapered surface. .

  The first nut accommodating portion 102 has an inner diameter that is the same as the outer diameter of the elastic accommodating portion 101, and has an internal thread formed on the inner peripheral surface thereof. The second nut housing portion 103 has an inner diameter that is the same as the outer diameter of the first nut housing portion 102, and an internal thread is formed on the inner peripheral surface thereof. The elastic member 91 is an O-ring having an insertion hole for inserting the rack shaft 20. The cross-sectional shape of the O-ring is a circle.

  The first nut 92 is screwed into the first nut housing portion 102 to crush the O-ring in the radial direction. The degree of screwing of the first nut 92 is adjusted, the degree of deformation of the O-ring is adjusted, and the size of the inner diameter of the O-ring is adjusted.

  The second nut 93 is screwed into the second nut housing portion 103 and presses the first nut 92. Thereby, it is suppressed that the 1st nut 92 rotates in the direction opposite to the screwing direction and goes outside, and the force with which the 1st nut 92 pushes an O-ring declines.

  The operation between the elastic member 91 and the rack shaft 20 will be described. The elastic member 91 is fitted into the elastic accommodating portion 101. The elastic member 91 is restricted from expanding in the radial direction. For this reason, by crushing the elastic member 91 in the axial direction of the rack shaft 20, the inner diameter of the elastic member 91 is reduced. The size of the inner diameter is adjusted by the degree of crushing of the elastic member 91. The crushing degree of the elastic member 91 is changed depending on the screwing degree of the first nut 92. When the frictional resistance between the inner peripheral portion 91A of the elastic member 91 and the rack shaft 20 is increased, the degree of screwing of the first nut 92 is increased. The structure of the first nut 92 that crushes the elastic member 91 functions as an adjustment mechanism 112 that adjusts the magnitude of the frictional resistance between the inner peripheral portion 91 </ b> A of the elastic member 91 and the rack shaft 20.

  Note that the action of the friction applying mechanism 90, that is, the force acting between the rack shaft 20 and the elastic member 91 when an impact is applied to the steered wheels and the transmission mode thereof are the same as in the first embodiment.

According to the steering device 1 of the present embodiment, in addition to the effects of the first embodiment (excluding the effect of (3) above), the following effects can be further achieved.
(7) In this embodiment, the elastic member 91 is an O-ring, and the inner peripheral portion 91 </ b> A of the O-ring is a portion that imparts frictional resistance to the rack shaft 20. And the adjustment mechanism 112 is comprised by the 1st nut 92 which crushes an O-ring and adjusts the magnitude | size of 91 A of internal peripheral parts.

  According to this configuration, the size of the inner diameter of the O-ring can be changed by adjusting the degree of deformation of the O-ring by the amount of movement of the first nut 92. Thereby, the magnitude | size of the frictional resistance provided to the rack shaft 20 can be adjusted easily.

(Other embodiments)
In addition, the embodiment of the present invention is not limited to the embodiment exemplified in each of the above-described embodiments, and can be implemented by changing it as shown below, for example. The following modifications are not applied only to the above embodiments, and different modifications can be combined with each other.

  In the first embodiment, one friction applying mechanism 50 is provided for the rack housing 30, but a plurality of the mechanisms may be provided. Even with such a configuration, the effects according to the above (1) to (5) can be obtained.

  In the second embodiment, a coil spring is used as a mechanism for pushing the elastic member 71. However, a leaf spring or other structure spring can be used. Instead of a mechanical spring, an elastic member such as a rubber spring may be used.

  In the third embodiment, one O-ring is provided for the rack housing 30, but a plurality of O-rings can be arranged in parallel. Even with such a configuration, the effect according to the above (7) can be obtained.

  In the third embodiment, an O-ring having a circular cross section is used as the elastic member 91. For example, a ring having a Y cross section, a ring having a L cross section, a ring having a U cross section, a ring having a D cross section, A ring having an X-shaped cross section can also be used. In other words, any ring body can be used as long as the elastic member 91 is deformed to reduce the inner diameter and impart frictional resistance to the rack shaft 20.

  In the third embodiment, the elastic accommodating portion 101 into which the O-ring as the elastic member 91 is fitted is formed as a stepped portion, but this can also be formed as a groove along the inner periphery of the rack housing 30. According to this configuration, the position of the O-ring is defined without fixing the O-ring to the rack housing 30 by the second nut 93. In the case of this configuration, the adjustment mechanism is configured by a ring member that is fitted into the groove. By selecting the thickness of the ring member, the degree of deformation of the O-ring is adjusted, and the inner diameter of the O-ring is adjusted.

  In each of the above embodiments, the friction applying mechanisms 50, 70, 90 are provided at the other end 30 </ b> B of the rack housing 30, but this can also be provided at the opposite end. Further, it may be provided at the center of the rack housing 30.

  In the above embodiment, the present invention is applied to the steering apparatus 1 in which the EPS actuator 3 is provided in the steering angle transmission mechanism 2, but the present invention is applied to the steering apparatus 1 in which the EPS actuator 3 is provided in the steering shaft. You can also Also in this case, the effect according to the effect of the embodiment can be obtained by adopting the configuration according to the embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Steering device, 2 ... Steering angle transmission mechanism, 3 ... EPS actuator, 4 ... Motor, 5 ... Deceleration mechanism, 10 ... Pinion shaft, 20 ... Rack shaft, 20A ... One end, 20B ... Other end, DESCRIPTION OF SYMBOLS 21 ... 1st contact part, 22 ... 2nd contact part, 23 ... 3rd contact part, 24 ... Connection part, 25 ... Support part, 26 ... Tooth part, 30 ... Rack housing, 30A ... One edge part, 30B ... The other end, 31 ... 1st bush, 32 ... 2nd bush, 33 ... 3rd bush, 34 ... Through-hole, 35 ... Pinion accommodation part, 36 ... Support accommodation part, 40 ... Support mechanism, 41 ... Roller, 42 DESCRIPTION OF SYMBOLS ... Roller spindle, 43 ... Bearing, 50 ... Friction provision mechanism, 51 ... Friction provision accommodating part, 52 ... First accommodation part, 53 ... Second accommodation part, 54 ... Lock nut, 60 ... Elastic member, 61 ... Perimeter wall, 62A ... 1st slit, 62B ... 2nd slot 63 ... tip end portion, 64 ... rear end portion, 65 ... inner peripheral surface, 66 ... outer peripheral surface, 67 ... insertion hole, 70 ... friction applying mechanism, 71 ... elastic member, 72 ... pressing spring, 73 ... compression nut, 74 ... Lock nut, 75 ... Insertion hole, 75A ... Inner peripheral surface, 76 ... Outer peripheral surface, 77 ... Rear end surface, 78 ... Slit, 80 ... Friction imparting accommodating portion, 81 ... Elastic accommodating portion, 82 ... Spring accommodating portion, 83 DESCRIPTION OF SYMBOLS ... Compression nut accommodating part, 84 ... Lock nut accommodating part, 90 ... Friction grant mechanism, 91 ... Elastic member, 91A ... Inner peripheral part, 92 ... First nut, 93 ... Second nut, 100 ... Friction grant accommodating part, 101 ... elastic housing part, 102 ... first nut housing part, 103 ... second nut housing part, 110, 111, 112 ... adjustment mechanism.

Claims (8)

In a steering apparatus comprising a rack shaft that operates a steered wheel, a pinion shaft that drives the rack shaft, a support mechanism that rolls and supports the rack shaft, and a rack housing that houses the rack shaft,
A steering device is provided between the rack housing and the rack shaft, wherein a friction applying mechanism is provided that applies friction resistance to the rack shaft and adjusts the magnitude of the friction resistance. In the steering apparatus according to claim 1,
The friction applying mechanism includes: an elastic member that applies the friction resistance to the rack shaft; an accommodation portion that is provided in the rack housing and accommodates the elastic member; and an adjustment mechanism that adjusts the magnitude of the friction resistance. A steering apparatus characterized by comprising: In the steering apparatus according to claim 2,
The elastic member is a cylindrical body having an insertion hole into which the rack shaft is inserted. A slit is provided along the axial direction of the cylindrical body, and the outer peripheral surface is tapered. , A male screw is formed on the outer peripheral surface,
The accommodating portion is formed such that an inner peripheral surface is formed in a tapered shape and a female screw is formed on the inner peripheral surface.
The said adjustment mechanism is comprised by the external thread of the said elastic member, and the internal thread of the said accommodating part. The steering apparatus characterized by the above-mentioned. In the steering apparatus according to claim 2,
The elastic member is a cylindrical body having an insertion hole into which the rack shaft is inserted, and the outer peripheral surface is formed in a tapered shape,
The accommodating portion has an inner peripheral surface formed in a tapered shape,
The said adjustment mechanism is provided with the press spring which presses the said elastic member to an axial direction in the state which inserted the said elastic member in the said accommodating part, and the nut which compresses this press spring. The steering apparatus characterized by the above-mentioned. In the steering apparatus according to claim 2,
The elastic member is a ring body, and an inner peripheral portion of the ring body is a portion that imparts frictional resistance to the rack shaft,
The adjustment mechanism is a nut that crushes the ring body to adjust the size of the inner peripheral portion. In the steering apparatus according to claim 2,
The elastic member is an O-ring, and an inner peripheral portion of the O-ring is a portion that imparts frictional resistance to the rack shaft.
The said accommodating part is formed as a groove | channel in which the said elastic member is fitted. The steering apparatus characterized by the above-mentioned. In the steering apparatus according to any one of claims 2 to 6,
A steering device comprising a lock nut for restricting looseness of the adjusting mechanism. In the steering apparatus according to any one of claims 1 to 7,
The rubbing mechanism is provided at an end of the rack housing.

Images