JP4947184B2 - Bearing mechanism with sliding bearing - Google Patents

Description

  The present invention relates to a bearing mechanism including a sliding bearing interposed between a rack shaft and a housing in order to support a rack shaft of an automobile, for example, so as to be capable of linear movement.

  A sliding bearing made of a synthetic resin is used as a bearing for a rack shaft that supports a rack shaft for steering of an automobile so that the rack shaft can move directly.

JP 2004-347105 A

  Sliding bearings have the advantages of lower cost and better vibration absorption than rolling bearings, but they require an appropriate clearance (bearing gap) between the sliding bearings and the rack shaft, so they occur on the rack shaft. There is a problem that a collision noise is generated between the rack shaft and the sliding bearing due to the vibration and is transmitted as an unpleasant sound to a person driving the automobile. If the clearance between the slide bearing and the rack shaft is reduced to suppress the occurrence of this collision noise, the friction torque increases, and the difference between the friction torque at the start of linear motion and during the linear motion increases and the rack is increased. It becomes a factor that hinders the stability of the friction torque, such as a fluctuation of the friction torque during the linear motion due to a stick-slip phenomenon or the like due to an outer diameter dimension error of the shaft.

  In addition, the rack shaft is supported by the housing through a sliding bearing so as to be able to move directly, but the roundness of the inner diameter of the housing is usually not so high, and a sliding bearing made of synthetic resin is press-fitted into the housing. When fixed, the sliding bearing is distorted due to the roundness of the inner diameter of the housing, resulting in a difference in clearance from the rack shaft, which also inhibits the stability of the friction torque.

  In Patent Document 1, it is possible to eliminate the collision noise with the rack shaft, reduce the linear frictional resistance, reduce the difference in the linear frictional resistance between when the linear motion starts and during linear motion, and Stable linear motion friction resistance can be obtained without being affected by the diameter error and the roundness of the inner diameter of the housing. Thus, the rack shaft can be supported smoothly and the rack shaft can be moved more smoothly. There have been proposed sliding bearings that can be fitted and bearing mechanisms comprising such sliding bearings.

  In this bearing mechanism, the sliding bearing is locked to the housing so that the sliding bearing does not come out of the housing in the axial direction. However, the housing is provided with a groove, while the sliding bearing is provided with a hook (claw). In the case of locking to prevent slipping out by fitting to the groove, there is a clearance (gap) between the flange and the housing in order to enable the mounting of the flange in the groove. Become. When such a clearance (gap) exists, the static friction resistance between the sliding bearing and the rack shaft is larger than the static friction resistance between the sliding bearing and the housing due to the influence of a lubricant such as applied grease. At the start of linear motion of the rack shaft, the slide bearing is linearly moved relative to the housing together with the rack shaft by the clearance, and then the rack shaft is linearly moved relative to the slide bearing. There is a possibility that the steering feeling at the steering wheel is impaired.

  The rack shaft bearing mechanism also has a function (flutter suppression effect) that prevents the slight vibration applied to the rack shaft from the wheels when traveling on the road surface from being transmitted to the steering wheel. In a bearing mechanism in which a clearance) exists, there is a possibility that the sliding bearing itself vibrates together with the vibration of the rack shaft and the flutter suppressing effect cannot be sufficiently obtained.

  The present invention has been made in view of the above-mentioned points. The object of the present invention is to eliminate the noise of collision with the rack shaft and to reduce the linear frictional resistance. It is possible to reduce the difference between the linear frictional resistance and the linear frictional resistance during movement, and to obtain a stable linear frictional resistance without being affected by the outer diameter error of the rack shaft and the roundness of the inner diameter of the housing. To provide a bearing mechanism that can smoothly support a shaft and make a linear movement of a rack shaft smoother, and can improve a steering feeling at a handle and sufficiently maintain a flutter suppressing effect. .

  A bearing mechanism according to the present invention includes a housing having a cylindrical inner peripheral surface, a rack shaft inserted into the housing and having a cylindrical outer peripheral surface, an inner peripheral surface of the housing, and a rack shaft. A sliding bearing interposed between the outer peripheral surface and the housing, wherein the housing has a locking groove on the inner peripheral surface, and the sliding bearing includes a cylindrical bearing body and the bearing. One slit provided in the main body and extending from one axial end surface of the bearing main body toward the other axial end surface of the bearing main body, and the other end surface of the bearing main body provided in the bearing main body The other slit extending from the bearing body toward one end surface of the bearing body, the plurality of sliding surfaces provided inside the bearing body and spaced apart from each other in the direction around the axis, and provided on the outer surface of the bearing body And at least one mounting groove An elastic ring that protrudes in the radial direction from the outer surface of the bearing main body and is fitted in the mounting groove so as to reduce the diameter of the bearing main body; Restricting means for elastically restricting the movement of the main body in the axial direction, the elastic ring is fitted into the housing with a tightening margin on the outer peripheral surface thereof, and the bearing main body is interposed via the sliding surface The rack shaft is mounted on the outer peripheral surface of the rack shaft by tightening with the elastic force of the elastic ring.

  According to the bearing mechanism of the present invention, when the bearing main body is inserted into the inner peripheral surface of the housing, the elastic ring protruding from the outer peripheral surface of the bearing main body is elastically deformed with a margin for the inner peripheral surface of the housing, The elastic deformation can absorb dimensional errors such as the roundness of the inner diameter of the housing. Further, according to such a bearing mechanism, the bearing main body whose diameter can be freely reduced by a slit having an open end with respect to both end faces of the bearing main body is reduced in diameter by an elastic ring and inserted into the rack shaft. Since the clearance between the rack shaft and the rack shaft is zero, the collision with the rack shaft can be eliminated. As a result, the generation of the collision sound transmitted as an unpleasant noise is eliminated. In addition, it is possible to reduce the difference in linear frictional resistance between the start of linear motion and during linear motion, and to absorb errors in the outer diameter of the rack shaft, thereby obtaining a stable linear frictional resistance.

  Further, according to the bearing mechanism of the present invention, the restricting means is arranged in the locking groove of the housing with an elastic allowance and elastically restricts the axial movement of the bearing body relative to the housing. Even if the static friction resistance between the sliding bearing and the rack shaft is larger than the static friction resistance with the housing, the sliding bearing is linearly moved in the axial direction with respect to the housing together with the rack shaft at the start of the linear movement of the rack shaft. The sliding bearing can be held against the housing, and the rack shaft can be moved in the axial direction with respect to the sliding bearing at the start of the linear movement of the rack shaft. Thus, the steering feeling with the steering wheel can be improved and the flutter suppression effect can be sufficiently maintained.

  In a preferred example, the restricting means is integrally provided on the outer surface on one end surface side of the bearing body and is disposed on the engaging groove on the inner peripheral surface of the housing, and on one end surface side of the bearing body. An arc-shaped groove provided, and another elastic ring fitted in the arc-shaped groove and projecting in the axial direction from one end face side of the bearing body. It is arranged in the locking groove on the surface with an elastic tightening margin by another elastic ring. In such an example of the restricting means, one end surface in the axial direction of the ridge defines a locking groove and faces one wall surface orthogonal to the axial direction of the housing, and the other end in the axial direction of the ridge The end surface of the shaft is in contact with the other wall surface orthogonal to the axial direction of the housing while defining the locking groove, and the portion protruding in the axial direction from the one end surface side of the bearing body in the other elastic ring is It is preferable that the locking groove is defined and elastically compressed by contacting one wall surface orthogonal to the axial direction of the housing. The arc-shaped groove may be provided on one end surface itself in the axial direction of the flange, but may instead be provided on one end surface itself of the bearing body, and further, in the axial direction of the flange. One end face and one end face of the bearing body may be provided. Therefore, even if the other elastic ring protrudes in the axial direction from one end face in the axial direction of the flange, it is replaced. Even if it protrudes in the axial direction from one end surface of the bearing body itself, it is further axial from both end surfaces of the axial end surface of the flange and one end surface of the bearing body that are usually flush with each other. May protrude.

  In another preferred example, the restricting means is provided integrally with the outer surface on one end face side of the bearing body and is disposed in the locking groove on the inner peripheral surface of the housing, and the radial direction of the flange An arc-shaped groove provided on the outer surface, and another elastic ring fitted in the arc-shaped groove and projecting radially from the outer surface in the radial direction of the flange. It is arranged in the locking groove on the peripheral surface with an elastic margin by another elastic ring. In another example of such restricting means, one end surface in the axial direction of the flange is in contact with one wall surface orthogonal to the axial direction of the housing defining the locking groove, and the axial direction of the flange is The other end surface is in contact with the other wall surface orthogonal to the axial direction of the housing that defines the locking groove, and the portion of the other elastic ring that protrudes radially from the outer surface in the radial direction of the flange is engaged. It may be elastically compressed in contact with the wall surface extending in the direction around the axis of the housing that defines the stop groove.

  In the above example, it is sufficient that at least one ridge is provided, and the same number as that of one slit is preferably provided.

  The restricting means also communicates with the mounting groove and extends in the axial direction integrally with at least one pair of axial grooves provided on the outer surface of the bearing body and extending in the axial direction from both end surfaces in the axial direction of the elastic ring. At least a pair of axial elastic projections that are fitted in the corresponding axial grooves and project in the axial direction from the corresponding end surfaces in the axial direction of the bearing body and are arranged in the locking grooves on the inner peripheral surface of the housing. And the axial movement of the bearing main body relative to the housing may be elastically restricted by the portions of the pair of axial elastic protrusions protruding in the axial direction. The portion protruding in the axial direction of one axial elastic protrusion is elastically compressed by a pair of wall surfaces orthogonal to the axial direction of the housing and a wall surface extending in the direction around the axial center of the housing. And locking groove The portion of the housing that is in contact with one wall surface orthogonal to the axial direction of the defining housing and that protrudes in the axial direction of the other axial elastic protrusion is elastically compressed and defines the locking groove. The elastic ring is in contact with the other wall surface perpendicular to the direction, the elastic ring extends in the direction around the axis of the housing on the outer peripheral surface thereof, contacts the wall surface defining the locking groove, and the shafts of the pair of axial elastic protrusions The portion protruding in the direction may have a radial thickness smaller than the radial thickness of the elastic ring.

  Depending on the elastic coefficient of the elastic ring, the elastic ring fitted in the mounting groove has an outer diameter that is about 0.3 mm to 1.0 mm larger than the diameter of the inner peripheral surface of the housing. In addition, a preferable example having a diameter smaller by about 0.3 mm to 1.0 mm than the diameter of the bottom surface of the mounting groove can be presented. However, in short, it has a tightening margin with respect to the inner peripheral surface of the housing, and a plurality of sliding surfaces. The rack shaft protrudes from the outer peripheral surface of the bearing body and the diameter of the bearing body is reduced to such an extent that the clearance between the sliding surface and the rack shaft is made zero by tightening the rack shaft with an appropriate elastic force. Specifically, it is sufficient that at least the outer diameter is larger than the diameter of the inner peripheral surface of the housing and the inner diameter is smaller than the diameter of the bottom surface of the groove.

  Any of the elastic rings may be a so-called O-ring having a circular cross section, but may be another X-shaped cross-section, a U-shaped cross-section or a trapezoidal ring, and the like. For example, any of natural rubber, synthetic rubber, and thermoplastic synthetic resin having elasticity, for example, polyester elastomer may be used.

  The inner peripheral surface of the housing having a cylindrical inner peripheral surface and having a locking groove on the inner peripheral surface, and the outer periphery of the rack shaft inserted into the housing and having a cylindrical outer peripheral surface The sliding bearing of the present invention interposed between the bearing body and the cylindrical bearing body, and one provided on the bearing body and extending from one end face of the bearing body toward the other end face of the bearing body The other slit that is provided in the bearing body and extends from the other end surface of the bearing body toward the one end surface of the bearing body, and the inner slit of the bearing body and the direction around the axis And a plurality of sliding surfaces spaced apart from each other, at least one mounting groove provided on the outer surface of the bearing body, and fitted in the mounting groove so as to project radially from the outer surface of the bearing body and reduce the diameter of the bearing body. Elastic phosphorus And a restricting means that elastically restricts the axial movement of the bearing body relative to the housing, and that is elastically restricted in the locking groove of the housing. The bearing body is fitted on the outer peripheral surface of the rack shaft by tightening the rack shaft with the elastic force of the elastic ring via the sliding surface.

  By using the sliding bearing according to the present invention for the above-mentioned bearing mechanism, the rack shaft can be supported smoothly, and the rack shaft can be moved more smoothly, and the steering feeling at the steering wheel can be improved. In addition, it is possible to provide a bearing mechanism that can sufficiently maintain the flutter suppressing effect.

  In the present invention, the bearing body may be provided with a plurality of one and other slits, each slit extending between a pair of sliding surfaces, and the one and the other slits are around the axis. The sliding surfaces are preferably arranged inside the bearing body at positions separated by a predetermined distance in the axial direction from both end surfaces of the bearing body. These sliding surfaces are preferably arranged at equal intervals in the direction around the shaft center.In a preferred example, at least two mounting grooves spaced apart from each other in the axial direction are provided on the outer peripheral surface of the bearing body. In addition, an elastic ring is fitted in each mounting groove so as to protrude from the outer peripheral surface of the bearing body and reduce the diameter of the bearing body, and the axial center portion of the sliding surface is between the two mounting grooves in the axial direction. Each sliding surface is a shaft It may be provided on the inner side of the bearing body between two of the mounting groove in the direction, or may be provided on the inner side of the bearing body beyond the two mounting grooves in the axial direction.

  In the present invention, the elastic ring fitted in the mounting groove may have a volume larger than the volume of the mounting groove. The elastic ring does not need to be arranged closely to the bearing body without a gap in the mounting groove, and may be fitted in the mounting groove with a slight gap with respect to the bearing body, and the diameter from the outer peripheral surface of the bearing body The portion of the elastic ring protruding in the direction may be deformed when it is properly pressed by the housing to completely fill the mounting groove, or the bearing is also pressed when properly pressed by the housing. While there is a slight gap with respect to the main body, when the housing is eccentric from the normal position with respect to the rack shaft due to an unintended external force and is partially pressed strongly by the housing, it is deformed at such excessively pressed portion. Thus, the groove may be completely filled to increase rigidity, thereby countering unintentional eccentricity of the housing.

  The slide bearing preferably has a clearance having a width of 0.3% to 10% of the maximum radial thickness of the bearing body at a portion that becomes a free end with respect to the housing, and the inner peripheral surface of the housing and the free end. It is generated between the outer peripheral surface of the bearing main body at the part to be a part. If the clearance is less than 0.3%, there is a risk that the housing will easily come into contact with the bearing body and generate abnormal noise when the housing is decentered from the normal position with respect to the rack shaft due to unintended external force. If the clearance is larger than 10%, the housing may be easily decentered from the normal position with respect to the rack shaft by an unintended external force, which may reduce the alignment effect of the bearing mechanism. As a result, contact of the housing with the bearing main body can be avoided, and the housing can be reliably held at a normal position with respect to the rack shaft.

  In the present invention, each sliding surface may be a flat surface, an arc-shaped projecting surface, or a concave surface. When each sliding surface is a flat surface, the sliding surfaces face each other in the radial direction and are parallel to each other. Even if the distance between the moving surfaces is smaller than the inner diameter of the bearing body at each end surface, if each sliding surface is an arcuate protruding surface, the distance between the tops of the sliding surfaces facing each other in the radial direction If each sliding surface is an arcuate concave surface even if it is smaller than the inner diameter of the bearing body at each end surface, the distance between the bottoms of the sliding surfaces facing each other in the radial direction is the bearing at each end surface. It may be smaller than the inner diameter of the main body.

  In each sliding surface, if it is a flat surface, even if the rack shaft is tightened with the elastic force of the elastic ring at its center in the direction around the shaft center, it is an arc-shaped protruding surface. If the rack shaft is tightened with the elastic force of the elastic ring at the top, and if it is an arcuate concave surface, the rack shaft is elastic at the bottom with the elasticity of the elastic ring. The arcuate concave surface may have a curvature smaller than or substantially the same as that of the outer peripheral surface of the rack shaft.

  In a preferred example, the inner side of the bearing body extends from one end surface of the bearing body to one end in the axial direction of the sliding surface and gradually decreases in diameter, and from the other end surface of the bearing body to the sliding surface. The other tapered surface extending to the other end in the axial direction and gradually decreasing in diameter, wherein one tapered surface has an axial length longer than the axial length of the other tapered surface. The one taper surface may have a taper angle larger than the taper angle of the other taper surface, and according to the slide bearing having such a taper surface, the bearing body from the one taper surface side. As a result, the assembly man-hours can be greatly reduced.

  In the bearing mechanism of the present invention, the plurality of sliding surfaces and the bearing body are integrally formed from a synthetic resin, and as the synthetic resin forming the plurality of sliding surfaces and the bearing body, polyacetal resin, polyamide Preferred examples include thermoplastic synthetic resins such as resins, polyethylene resins, and ethylene tetrafluoride resins.

  According to the present invention, the collision noise with the rack shaft can be eliminated, the linear friction resistance can be reduced, and the difference in the linear friction resistance between the start of the linear motion and during the linear motion can be reduced. Stable linear motion friction resistance can be obtained without being affected by the outer diameter error and the roundness of the inner diameter of the housing. Thus, the rack shaft can be supported smoothly and the linear motion of the rack shaft can be made smoother. In addition, it is possible to provide a bearing mechanism that can improve the steering feeling with the steering wheel and can sufficiently maintain the flutter suppression effect.

FIG. 3 is an explanatory view including a cross section taken along line I-I shown in FIG. 2 of the sliding bearing in a preferred example of the present invention. It is a left side explanatory view of the slide bearing of the example shown in FIG. It is right side explanatory drawing of the slide bearing of the example shown in FIG. FIG. 2 is an external explanatory view of a sliding bearing in the example shown in FIG. 1. It is a partially expanded explanatory view of the example shown in FIG. It is explanatory drawing of the other preferable example of this invention. It is an external view explanatory drawing of the slide bearing of the example shown in FIG. It is explanatory drawing of the example shown in FIG. It is explanatory drawing containing the IX-IX arrow line cross section shown in FIG. 10 of a sliding bearing in the preferable example of this invention. FIG. 10 is a left side explanatory view of the slide bearing of the example shown in FIG. 9. It is right side explanatory drawing of the slide bearing of the example shown in FIG. FIG. 10 is an external explanatory view of a sliding bearing in the example shown in FIG. 9. FIG. 10 is a partially enlarged explanatory diagram of the example shown in FIG. 9.

  Hereinafter, the present invention and preferred embodiments thereof will be described with reference to the drawings. The present invention is not limited to these examples.

  1 to 5, a bearing mechanism 1 of this example includes a housing 3 having a cylindrical inner peripheral surface 2, and a rack shaft that is inserted into the housing 3 and has a cylindrical outer peripheral surface 4. 5 and a plain bearing 6 interposed between the inner peripheral surface 2 of the housing 3 and the outer peripheral surface 4 of the rack shaft 5.

  The housing 3 has an annular locking groove 11 on its inner peripheral surface 2, and the locking groove 11 is an annular shape orthogonal to the axial direction A that is the direction along the axis X of the housing 3. Are defined by a pair of wall surfaces 12 and 13 and an annular wall surface 14 extending in a circumferential direction B which is a direction around the axis X of the housing 3.

  The rack shaft 5 that is movable in the axial direction A is connected to the steering wheel on the one hand and to the wheel on the other hand via a connecting mechanism, and such a connecting mechanism is known and will not be described.

  The sliding bearing 6 includes a cylindrical bearing body 21 and six pieces provided on the bearing body 21 so as to extend from one end surface 22 of the bearing body 21 in the axial direction A toward the other end surface 23 of the bearing body 21. Of the bearing body 21, six slits 25 provided in the bearing body 21 extending in the axial direction A from the other end face 23 of the bearing body 21 toward the one end face 22 of the bearing body 21, and the bearing body 21. Are provided on the outer surface 27 of the bearing body 21 and a plurality of arcuate concave surfaces 26 serving as twelve sliding surfaces in this example and spaced apart from each other in the circumferential direction B by the slits 24 and 25. At least one of the two mounting grooves 28 in this example, an elastic ring 29 protruding from the outer surface 27 of the bearing body 21 and fitted in each of the mounting grooves 28 so as to reduce the diameter of the bearing body 21; How Is provided with a regulating means 30 for movement in the axial direction A of the bearing body 21 elastically regulated with respect to the housing 3 with is arranged with an elastic interference in the locking groove 11 of the ring 3.

  The bearing body 21 and the concave surface 26 are integrally formed from a synthetic resin, for example, a thermoplastic synthetic resin such as a polyacetal resin or a polyamide resin.

  Twelve concave surfaces 26 each having substantially the same curvature as that of the outer peripheral surface 4 of the rack shaft 5 are arranged at equal intervals in the circumferential direction B, that is, at an angular interval of 30 °. The concave surface 26 is provided between the both end surfaces 22 and 23 of the bearing body 21 at a predetermined distance in the axial direction A and beyond the two mounting grooves 28 in the axial direction A, and is provided inside the bearing body 21. Moreover, the central portion of each concave surface 26 in the axial direction A is located between the two mounting grooves 28 in the axial direction A.

  In addition to the concave surface 26, the inner side of the bearing body 21 extends from the end surface 22 to the one end 31 in the axial direction A of the concave surface 26 and gradually decreases in diameter, and the other end in the axial direction A of the concave surface 26 from the end surface 23. The taper surface 34 extends to 33 and gradually decreases in diameter, the groove 35 extends in the axial direction A from the end surface 22 and is connected to one end in the axial direction A of each slit 25, and extends in the axial direction A from the end surface 23. A groove 36 connected to one end of the slit 24 in the axial direction A, and each concave surface 26 has an inner diameter smaller than the inner diameter of the bearing body 21 at the end surfaces 22 and 23, and the bearing at the end surface 22. The main body 21 has an inner diameter smaller than the inner diameter of the bearing main body 21 at the end face 23.

  The slits 24 opened on the end surface 22 side are arranged at equal intervals in the circumferential direction B, that is, at an angular interval of 60 °, and extend beyond the mounting groove 28 on the end surface 23 side in the axial direction A. The slits 25 that are open on the end face 23 side and are arranged between the slits 24 in the circumferential direction B are also arranged at equal intervals in the circumferential direction B, that is, at an angular interval of 60 °, and in the axial direction. In A, the slits 24 and 25 extend beyond the mounting groove 28 on the end face 22 side, and the slits 24 and 25 are arranged at equal intervals in the circumferential direction B, that is, at an angular interval of 30 °, and are alternately arranged in the circumferential direction B. Has been.

  Each of the slits 24 and 25 may be one, but the configuration as in this example is preferable because the reduced diameter of the bearing body 21 can be obtained uniformly and easily.

  Two mounting grooves 28 provided on the outer surface 27 of the bearing body 21 so as to be separated from each other in the axial direction A are defined by three annular projections 37, 38 and 39 on the outer surface 27 side of the bearing body 21. The diameters of the outer surface 27 of the bearing body 21 at the protrusions 37, 38 and 39 are equal to each other, but smaller than the diameter of the inner peripheral surface 2 of the housing 3.

  In this example, from 10% to 10% of the maximum radial thickness T of the bearing body 21 at a portion that is a free end with respect to the housing 3, that is, at a portion of the protrusion 39 on the end face 23 side that does not engage with the housing 3. The clearance 40 having a width (thickness) D of% is generated between the inner peripheral surface 2 of the housing 3 and the outer surface 27 at a portion to be a free end portion of the bearing body 21. 3 can be prevented from coming into contact with the outer surface 27 at the portion of the protrusion 39 of the bearing body 21 and the housing 3 can be securely held at a normal position with respect to the rack shaft 5.

  Each elastic ring 29 made of an O-ring is not fitted on the inner peripheral surface 2 of the housing 3, but has an outer diameter larger than the diameter of the inner peripheral surface 2 of the housing 3 in a state of being attached to the mounting groove 28. And has an inner diameter smaller than the diameter of the bottom surface 41 of the mounting groove 28 in a state where it is not fitted to the inner peripheral surface 2 of the housing 3 and is not mounted to the mounting groove 28. Thus, each of the elastic rings 29 that protrude from the outer surface 27 of the protrusions 37, 38, and 39 of the bearing body 21 and are fitted in the mounting groove 28 so as to reduce the diameter of the bearing body 21 is fitted. The mounting groove 28 has a volume larger than that of the mounting groove 28, and even if it is tightened and deformed to fill the mounting groove 28 without a gap, it partially protrudes from the outer surface 27.

  Each elastic ring 29 is fitted to the inner peripheral surface 2 of the housing 3 with a tightening margin at the outer peripheral surface, and the bearing body 21 has a clearance 40 between the outer surface 27 and the inner peripheral surface 2 of the housing 3. The rack shaft 5 is mounted on the outer peripheral surface 4 of the rack shaft 5 by being arranged on the inner peripheral surface 2 of the housing 3 and tightening the rack shaft 5 with the elastic force of the elastic ring 29 via the concave surface 26.

  The restricting means 30 is provided integrally with the outer surface 27 on the end surface 22 side of the bearing main body 21 and has six arc-shaped flanges 42 disposed in the locking grooves 11 of the inner peripheral surface 2 of the housing 3. An arc-shaped groove 43 provided on the end surface 22 of the bearing body 21 and an annular elastic ring 44 that is fitted in the arc-shaped groove 43 and that protrudes from the end surface 22 are formed.

  One end surface 45 in the axial direction A of the flange 42 faces one wall surface 12 orthogonal to the axial direction A of the housing 3 that defines the locking groove 11, and the other end surface 45 in the axial direction A of the flange 42. The end surface 47 is in contact with the other wall surface 13 orthogonal to the axial direction A of the housing 3 that defines the locking groove 11, and is flush with one end surface 45 of the flange 42 in the axial direction A of the flange 42. A portion 46 projecting in the axial direction A from the end surface 22 of the first contact portion is in contact with one wall surface 12 defining the locking groove 11 and is elastically compressed, and the other end surface 47 of the flange 42 in the axial direction A is The flange 42 is in contact with the other wall surface 13 that defines the locking groove 11. Thus, the flange 42 is arranged in the locking groove 11 on the inner peripheral surface 2 of the housing 3 with an elastic tightening margin by the elastic ring 44. The restricting means 30 protrudes in the axial direction A from the flange 42 and the end face 22. It has a movement in the axial direction A of the bearing body 21 with respect to the housing 3 so as to elastically regulated by the elastic ring 44 arranged on the Rutotomoni arc-shaped grooves 43.

  In the above bearing mechanism 1, the elastic ring 29 is fitted into the mounting groove 28 of the outer surface 27 of the bearing main body 21, whereby the bearing main body 21 having the slits 24 and 25 is reduced in diameter by the elastic compressive force of the elastic ring 29. The sliding bearing 6 with the reduced diameter of the bearing body 21 is disposed in the housing 3, and then the rack shaft 5 is inserted inside the bearing body 21, whereby the bearing body 21 is elastically compressed by the elastic ring 29. In contrast, the rack shaft 5 is expanded by the slit 24 and the rack shaft 5 is tightened by the concave surface 26 with the elastic compression force of the elastic ring 29 at the outer peripheral surface 4, while each elastic ring 29 is tightened by the outer peripheral surface. In contact with the inner peripheral surface 2 of the housing 3 and elastically with the flange 42 due to the compressive deformation of the portion 46 of the elastic ring 44 having an elastic tightening allowance. It will be placed in the locking groove 11 without gap in the axial direction A and the ring 44.

  Therefore, the clearance between the concave surface 26 and the rack shaft 5 becomes zero, and the collision between the bearing main body 21 and the rack shaft 5 can be eliminated, and as a result, no collision noise is transmitted as unpleasant noise to the driver. The elastic ring 29 fitted in the mounting groove 28 of the bearing body 21 has a tightening margin with respect to the inner peripheral surface 2 of the housing 3, so that the elastic ring 29 is elastically deformed, and the inner diameter of the housing 3 is reduced by the elastic deformation. A dimensional error such as roundness can be absorbed, and the flange 42 and the elastic ring 44 of the restricting means 30 are arranged in the locking groove 11 of the housing 3 with an elastic margin, and the bearing body 21 with respect to the housing 3 is arranged. In order to elastically restrict the movement in the axial direction A, the concave surface 26 of the sliding bearing 6 and the outer peripheral surface 4 of the rack shaft 5 are more than the static friction resistance between the elastic ring 29 and the inner peripheral surface 2 of the housing 3. Even when the static frictional resistance between them is large, it is possible to elastically prevent the sliding bearing 6 from being linearly moved in the axial direction A with respect to the housing 3 together with the rack shaft 5 when the linear movement of the rack shaft 5 in the axial direction A is started. Thus, the sliding bearing 6 can be held with respect to the housing 3, and the rack shaft 5 is linearly moved in the axial direction A with respect to the sliding bearing 6 even when the linear movement of the rack shaft 5 is started, In addition to improving the steering feel at the steering wheel, the flutter suppression effect can be sufficiently maintained.

  In the restricting means 30, the elastic ring 44 is provided on the end face 22, but instead of or together with this, as shown in FIGS. 6 to 8, the elastic ring 44 is provided on the outer surface 51 in the radial direction of the flange 42. It may be provided. That is, the restricting means 30 shown in FIGS. 6 to 8 is a circle provided on the radially semicircular outer surface 51 which is the respective surface of the flange 42 in addition to the flange 42 arranged in the locking groove 11. An arc-shaped groove 52 and an elastic ring 44 fitted in the arc-shaped groove 52 and projecting radially from the outer surface 51 of the flange 42 are provided, and one end face 45 in the axial direction A of the flange 42 is The other end surface 47 in the axial direction A of the flange 42 is in contact with the other wall surface 13 of the housing 3 that defines the locking groove 11. The portion 53 of the elastic ring 44 protruding in the radial direction from the radial outer surface 51 of the flange 42 comes into contact with the wall surface 14 of the housing 3 defining the locking groove 11 and is elastically compressed. With the compressed elastic ring 44, the thickness in the axial direction A is expanded. Flange 42 which is viewed deformation is arranged with an elastic interference due to the elastic ring 44 to the locking groove 11 of the inner peripheral surface 2 of the housing 3. It should be noted that the portion 53 of the elastic ring 44 does not have to be elastically compressed simply by contacting the wall surface 14 of the housing 3. In this case, the elastic ring 44 increases the thickness of the flange 42 in the axial direction A. It is good to be fitted in the arc-shaped groove 52 as described above.

  The elastic ring 44 increases the thickness in the axial direction A and elastically restricts the movement of the bearing body 21 in the axial direction A relative to the housing 3 by the flange 42 disposed in the locking groove 11. Also in the bearing mechanism 1 shown in FIGS. 6 to 8, the elastic rings 29 protruding from the outer surface 27 of the bearing body 21 are elastically deformed with a margin with respect to the inner peripheral surface 2 of the housing 3, and A dimensional error such as the roundness of the inner diameter of the housing 3 is absorbed, and the bearing body 21 whose diameter can be freely reduced by the slits 24 and 25 is reduced in diameter by the elastic ring 29 and inserted into the rack shaft 5. Is tightened by the concave surface 26, the clearance with the rack shaft 5 can be reduced to zero, the collision with the rack shaft 5 can be eliminated, and the concave surface 26 is made of synthetic resin. The friction torque with the outer peripheral surface 4 of the shaft 5 can be reduced, and the flange 42 of the restricting means 30 is disposed in the locking groove 11 of the housing 3 with an elastic tightening margin by the elastic ring 44. In order to elastically restrict the movement of the bearing body 21 in the axial direction A with respect to 3, the concave surface 26 of the sliding bearing 6 and the rack shaft 5 rather than the static frictional resistance between the elastic ring 29 and the inner peripheral surface 2 of the housing 3. Even when the static frictional resistance with the outer peripheral surface 4 of the rack shaft 5 is large, the sliding bearing 6 is linearly moved in the axial direction A with respect to the housing 3 together with the rack shaft 5 when the linear movement of the rack shaft 5 in the axial direction A is started. Can be held elastically and the sliding bearing 6 can be held with respect to the housing 3, and the rack shaft 5 moves linearly in the axial direction A with respect to the sliding bearing 6 even when the rack shaft 5 starts to move. Therefore, FIG. The bearing mechanism 1 shown in FIG. 8 can also eliminate the occurrence of a collision sound transmitted as an unpleasant sound to the driver, can make the steering operation smoother, and can improve the steering feeling at the steering wheel. Moreover, the flutter suppression effect can be sufficiently maintained.

  The bearing mechanism 1 includes the sliding bearing 6 that is asymmetrical between the end face 22 side and the end face 23 side. Instead, as shown in FIGS. 9 to 13, the end face 22 side and the end face 23 side are provided. And a symmetrical sliding bearing 6 may be provided. That is, the sliding bearing 6 shown in FIGS. 9 to 13 extends in the axial direction A from the one end face 22 of the bearing body 21 toward the other end face 23 of the bearing body 21. Three slits 24 provided in the bearing main body 21 and three slits 24 provided in the bearing main body 21 extending in the axial direction A from the other end face 23 of the bearing main body 21 toward the one end face 22 of the bearing main body 21. A plurality of slits 25, six arc-shaped concave surfaces 26 serving as a plurality of sliding surfaces, which are provided inside the bearing body 21 and divided by the slits 24 and 25 in the circumferential direction B, and the bearing body One mounting groove 28 provided on the outer surface 27 of the bearing 21, an elastic ring 29 that protrudes from the outer surface 27 of the bearing body 21 and is fitted in the mounting groove 28 so as to reduce the diameter of the bearing body 21, and the housing 3. Locking groove 1 and a restricting means 30 that elastically restricts the movement of the bearing body 21 in the axial direction A with respect to the housing 3. 13 is defined by an annular wall surface 14 extending in the circumferential direction B constituting a part of the inner peripheral surface 2, and the mounting groove 28 is arranged in the central portion of the concave surface 26 in the axial direction A. The tapered surface 32 has the same length in the axial direction A as the tapered surface 34, and the groove 35 extends from the end surface 22 in the axial direction A and is connected to one end in the axial direction A of each slit 25. The groove 36 extends in the axial direction A from the end surface 23 and is connected to one end of the slit 24 in the axial direction A. The slits 24 opened on the end surface 22 side are 120 in the circumferential direction B. Axial direction with angular spacing of ° The slits 25 that extend beyond the mounting groove 28 in A, open on the end face 23 side, and are arranged between the slits 24 in the circumferential direction B are also arranged at an angular interval of 120 ° with respect to each other in the circumferential direction B. And extends beyond the mounting groove 28 in the axial direction A. The slits 24 and 25 are equally spaced in the circumferential direction B, that is, at an angular interval of 60 °, and in the circumferential direction B. Alternatingly arranged.

  In the sliding bearing 6 shown in FIGS. 9 to 13, the flat elastic ring 29 extending in the axial direction A is not fitted to the inner peripheral surface 2 of the housing 3, but is fitted to the mounting groove 28. The mounting groove has an outer diameter larger than the diameter of the inner peripheral surface 2 of the housing 3 and is not fitted to the inner peripheral surface 2 of the housing 3 and is not fitted to the mounting groove 28. 28 has an inner diameter smaller than the diameter of the bottom surface 41 of the bearing 28, and thus is projected from the outer surface 27 of the bearing body 21 and fitted in the mounting groove 28 so as to reduce the diameter of the bearing body 21. The outer peripheral surface is fitted to the inner peripheral surface 2 of the housing 3 with a tightening allowance, so that the bearing body 21 has a clearance 40 between the outer surface 27 and the wall surface 14 of the inner peripheral surface 2 of the housing 3. 3 is arranged on the wall surface 14 of the inner peripheral surface 2 And with that, which is mounted on the outer peripheral surface 4 of the rack shaft 5 a rack shaft 5 via the concave surface 26 is tightened with an elastic force of the elastic ring 29.

  In the bearing mechanism 1 shown in FIGS. 9 to 13, the restricting means 30 communicates with the mounting groove 28 and extends in the axial direction A and is provided on the outer surface 27 of the bearing body 21, and in this example, six pairs. The axial grooves 61 and 62 of the elastic ring 29 and the axial grooves A and 62 are fitted into the corresponding axial grooves 61 and 62 so as to extend integrally from both end faces 63 and 64 of the elastic ring 29 in the axial direction A, respectively. At least a pair of axial projections in the axial direction A of the bearing body 21 projecting in the axial direction A from the corresponding end faces 22 and 23 in the inner circumferential surface 2 of the housing 3, in this example, six pairs of axial elastic projections 65 and 66, and the movement of the bearing body 21 in the axial direction A with respect to the housing 3 is elastically restricted by the portions 67 and 68 protruding in the axial direction A of the pair of axial elastic protrusions 65 and 66. It has become A portion 67 of the axial elastic protrusion 65 protruding in the axial direction A defines the locking groove 11 and is in contact with one wall surface 12 orthogonal to the axial direction A of the housing 3 to be elastically compressed. A portion 68 of the axial elastic protrusion 65 protruding in the direction A defines the locking groove 11 and contacts the other wall surface 13 orthogonal to the axial direction A of the housing 3 and is elastically compressed. Each of the axial elastic protrusions 65 and 66 has a step portion 69 in the middle of the axial direction A, and each axial elastic protrusion 65 extends from the end surface 63 in the axial direction A of the elastic ring 29 to the step portion 69. The elastic ring 29 has the same radial thickness as that of the elastic ring 29, and has a radial thickness smaller than the radial thickness of the elastic ring 29 from the stepped portion 69 to its free end. Similarly, each axial elastic protrusion 66 has an elastic ring. 9 has a radial thickness equal to the radial thickness of the elastic ring 29 from the end face 64 in the axial direction A to the step portion 69, and the radial direction of the elastic ring 29 extends from the step portion 69 to its free end. Therefore, the portions 67 and 68 projecting in the axial direction A of each pair of the axial elastic projections 65 and 66 are the radial thickness of the elastic ring 29. Less radial thickness.

  Also in the bearing mechanism 1 shown in FIGS. 9 to 13, the elastic ring 29 protruding from the outer surface 27 of the bearing body 21 is elastically deformed with a margin with respect to the wall surface 14 of the inner peripheral surface 2 of the housing 3. Due to the elastic deformation, a dimensional error such as the roundness of the inner diameter of the wall surface 14 of the housing 3 is absorbed, and the bearing body 21 that can be reduced in diameter by the slits 24 and 25 is reduced in diameter by the elastic ring 29 and inside thereof. Since the inserted rack shaft 5 is tightened with the concave surface 26, the clearance between the rack shaft 5 and the rack shaft 5 can be reduced to zero, and the concave surface 26 is made of synthetic resin. The friction torque with the outer peripheral surface 4 of the rack shaft 5 can be reduced, and the axial elastic protrusions 65 and 66 of the restricting means 30 are elastically tightened in the locking groove 11 of the housing 3. In order to elastically restrict the movement of the bearing body 21 in the axial direction A relative to the housing 3, the sliding bearing is more effective than the static friction resistance between the elastic ring 29 and the wall surface 14 of the inner peripheral surface 2 of the housing 3. 6, even when the static frictional resistance between the concave surface 26 of the rack 6 and the outer peripheral surface 4 of the rack shaft 5 is large, the slide bearing 6 is pivoted together with the rack shaft 5 with respect to the housing 3 when the rack shaft 5 starts to move in the axial direction A. The sliding bearing 6 can be held elastically against the housing 3 by being elastically prevented from being linearly moved in the direction A, and the axial direction with respect to the sliding bearing 6 can be maintained even when the rack shaft 5 starts to move. The rack shaft 5 is moved linearly to A. Therefore, the bearing mechanism 1 shown in FIGS. 9 to 13 can also eliminate the occurrence of a collision sound transmitted as an unpleasant sound to the driver, thereby further improving the steering operation. What to do smoothly On possible, on which can improve the steering feeling of the handle can be maintained sufficiently flutter suppression effect.

  In the above description, each sliding surface is constituted by the concave surface 26, but each sliding surface may be constituted by an arcuate projecting surface or a flat surface instead.

DESCRIPTION OF SYMBOLS 1 Bearing mechanism 2 Inner peripheral surface 3 Housing 4 Outer peripheral surface 5 Rack shaft 6 Sliding bearing 11 Locking groove 21 Bearing body 22, 23 End surface 24, 25 Slit 26 Concave surface 27 Outer surface 28 Mounting groove 29 Elastic ring 30 Control means

Claims (4)

  A housing having a cylindrical inner peripheral surface, a rack shaft inserted into the housing and having a cylindrical outer peripheral surface, and interposed between the inner peripheral surface of the housing and the outer peripheral surface of the rack shaft The housing has a locking groove on the inner peripheral surface thereof, and the sliding bearing is provided in the cylindrical bearing body, and the bearing body and the bearing body. One slit extending from one end face in the axial direction toward the other end face in the axial direction of the bearing body, and provided in the bearing body and from the other end face of the bearing body toward one end face of the bearing body The other extended slit, a plurality of sliding surfaces provided inside the bearing body and spaced apart from each other in the direction around the axis, at least one mounting groove provided on the outer surface of the bearing body, and the bearing body Radially from the outer surface of the The elastic ring fitted in the mounting groove so as to reduce the diameter of the bearing body, and the elastic locking margin is arranged in the locking groove of the housing and elastically moves the bearing body in the axial direction relative to the housing. And the elastic ring is fitted into the housing with a tightening margin on the outer peripheral surface thereof, and the bearing body has the rack shaft attached to the elastic ring via a plurality of sliding surfaces. It is tightened with elasticity and attached to the outer peripheral surface of the rack shaft, and the restricting means is integrally provided on the outer surface on one end surface side of the bearing body and is disposed in the engaging groove on the inner peripheral surface of the housing. An arc-shaped groove provided on one end surface side of the bearing body, and another elastic ring fitted in the arc-shaped groove and protruding in the axial direction from the one end surface side of the bearing body, It has Is arranged in the locking groove on the inner peripheral surface of the housing with an elastic margin by another elastic ring. The locking groove includes a pair of wall surfaces orthogonal to the axial direction of the housing and a shaft of the housing. One end surface in the axial direction of the collar is defined as a locking groove, and one wall surface of the pair of wall surfaces orthogonal to the axial direction of the housing is defined by the wall surface extending in the direction around the center. The other end surface in the axial direction of the flange is in contact with the other wall surface of the pair of wall surfaces that define the locking groove and are orthogonal to the axial direction of the housing, and the other elastic ring Is a portion protruding in the axial direction from one end surface side of the bearing main body, defining a locking groove and contacting and elastically compressing one wall surface orthogonal to the axial direction of the housing .   A housing having a cylindrical inner peripheral surface, a rack shaft inserted into the housing and having a cylindrical outer peripheral surface, and interposed between the inner peripheral surface of the housing and the outer peripheral surface of the rack shaft The housing has a locking groove on the inner peripheral surface thereof, and the sliding bearing is provided in the cylindrical bearing body, and the bearing body and the bearing body. One slit extending from one end face in the axial direction toward the other end face in the axial direction of the bearing body, and provided in the bearing body and from the other end face of the bearing body toward one end face of the bearing body The other extended slit, a plurality of sliding surfaces provided inside the bearing body and spaced apart from each other in the direction around the axis, at least one mounting groove provided on the outer surface of the bearing body, and the bearing body Radially from the outer surface of the The elastic ring fitted in the mounting groove so as to reduce the diameter of the bearing body, and the elastic locking margin is arranged in the locking groove of the housing and elastically moves the bearing body in the axial direction relative to the housing. And the elastic ring is fitted into the housing with a tightening margin on the outer peripheral surface thereof, and the bearing body has the rack shaft attached to the elastic ring via a plurality of sliding surfaces. It is tightened with elasticity and attached to the outer peripheral surface of the rack shaft, and the restricting means is integrally provided on the outer surface on one end surface side of the bearing body and is disposed in the engaging groove on the inner peripheral surface of the housing. And an arc-shaped groove provided on the outer surface in the radial direction of the flange, and another elastic ring fitted in the arc-shaped groove and projecting radially from the outer surface in the radial direction of the flange. It has It is arranged in the locking groove on the inner peripheral surface of the ging with an elastic tightening margin by another elastic ring. The locking groove has a pair of wall surfaces orthogonal to the axial direction of the housing, and around the axis of the housing. One end surface in the axial direction of the flange is in contact with one wall surface of the pair of wall surfaces orthogonal to the axial direction of the housing defining the locking groove. The other end surface in the axial direction of the flange is in contact with the other wall surface of the pair of wall surfaces orthogonal to the axial direction of the housing defining the locking groove, and the other elastic ring is A bearing mechanism that is elastically compressed in contact with a wall surface extending in a direction around an axis of a housing that defines a locking groove at a portion protruding in a radial direction from a radially outer surface.   The inner peripheral surface of the housing having a cylindrical inner peripheral surface and having a locking groove on the inner peripheral surface, and the outer periphery of the rack shaft inserted into the housing and having a cylindrical outer peripheral surface A cylindrical bearing body and one of the sliding bearings provided on the bearing body and extending from one end face of the bearing body toward the other end face of the bearing body A slit, the other slit provided in the bearing body and extending from the other end face of the bearing body toward the one end face of the bearing body, and provided in the bearing body and in the direction around the axis. A plurality of sliding surfaces spaced apart from each other, at least one mounting groove provided on the outer surface of the bearing body, and fitted in the mounting groove so as to project radially from the outer surface of the bearing body and reduce the diameter of the bearing body. Elastic ring And a restricting means for elastically restricting the axial movement of the bearing body relative to the housing, and elastically tightening the elastic ring at its outer peripheral surface. The bearing body is fitted to the housing with a margin, and the bearing body is mounted on the outer peripheral surface of the rack shaft by tightening the rack shaft with the elastic force of the elastic ring via a plurality of sliding surfaces. Is provided integrally with the outer surface of one end surface side of the bearing body and is disposed in the engaging groove on the inner peripheral surface of the housing, and the arc-shaped groove provided on one end surface side of the bearing body. And another elastic ring that is fitted in the arc-shaped groove and protrudes in the axial direction from one end face side of the bearing body, and the flange is formed in the engaging groove on the inner peripheral surface of the housing. Elastic with other elastic rings One end face in the axial direction of the collar is configured to define a locking groove and to face one wall surface orthogonal to the axial direction of the housing, The other axial end surface of the flange defines a locking groove and is in contact with the other wall surface orthogonal to the axial direction of the housing, and the other elastic ring is one end surface of the bearing body. A sliding bearing that protrudes in the axial direction from the side, defines a locking groove, and comes into contact with one wall surface orthogonal to the axial direction of the housing so as to be elastically compressed.   The inner peripheral surface of the housing having a cylindrical inner peripheral surface and having a locking groove on the inner peripheral surface, and the outer periphery of the rack shaft inserted into the housing and having a cylindrical outer peripheral surface A cylindrical bearing body and one of the sliding bearings provided on the bearing body and extending from one end face of the bearing body toward the other end face of the bearing body A slit, the other slit provided in the bearing body and extending from the other end face of the bearing body toward the one end face of the bearing body, and provided in the bearing body and in the direction around the axis. A plurality of sliding surfaces spaced apart from each other, at least one mounting groove provided on the outer surface of the bearing body, and fitted in the mounting groove so as to project radially from the outer surface of the bearing body and reduce the diameter of the bearing body. Elastic ring And a restricting means for elastically restricting the axial movement of the bearing body relative to the housing, and elastically tightening the elastic ring at its outer peripheral surface. The bearing body is fitted to the housing with a margin, and the bearing body is mounted on the outer peripheral surface of the rack shaft by tightening the rack shaft with the elastic force of the elastic ring via a plurality of sliding surfaces. Is formed integrally with the outer surface of one end surface side of the bearing body and is disposed in the engaging groove on the inner peripheral surface of the housing, and the arc-shaped groove provided on the outer surface in the radial direction of the flange. And another elastic ring that is fitted in the arc-shaped groove and protrudes in the radial direction from the outer surface in the radial direction of the flange, and the flange is in the engagement groove on the inner peripheral surface of the housing. Elastic allowance by elastic ring One end surface in the axial direction of the rod is in contact with one wall surface orthogonal to the axial direction of the housing defining the locking groove, and the shaft of the rod The other end surface in the direction comes into contact with the other wall surface orthogonal to the axial direction of the housing defining the locking groove, and the other elastic ring is radially extended from the outer surface in the radial direction of the flange. A sliding bearing that is elastically compressed in contact with a wall surface extending in a direction around an axis of a housing that defines a locking groove at a protruding portion.

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