JP2011201542A - Rack guide and rack-and-pinion type steering device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack guide capable of eliminating emission of noises such as colliding sounds due to swings, solving inconvenience originating from the use of "similar metals", precluding generation of a sealed air chamber between the rack guide and a housing, making it unlikely for the rack guide to hop around, and also allowing quick movement in the axial direction relative to the housing, and further of moving instantly in response to the displacement of a rack bar in the direction perpendicular to its straight moving direction, and to provide a rack-and-pinion type steering device equipped with the rack guide.SOLUTION: The rack-and-pinion type steering device 1 is equipped with a pinion 2 rotatable in the R-direction, the rack bar 4 having teeth 3 to mesh with the pinion 2 and able to make straight motion in the A-direction, the housing 5 to support the pinion 2 rotatably in the R-direction, the rack guide 6 to support the rack bar 4 slidably, and a resilient means 7 to press the rack guide 6 toward the pinion 2.

Description

  The present invention relates to a rack guide that supports a rack bar of a steering mechanism of an automobile and a rack and pinion type steering apparatus that includes the rack guide.

  A rack and pinion type steering device is usually provided with a housing, a pinion rotatably supported by the housing, a rack bar having rack teeth meshing with the pinion, and a rack bar arranged in the housing so that the rack bar can slide freely. A rack guide to be supported and elastic means such as a coil spring for pressing the rack guide toward the rack bar are provided.

JP-A-10-217985

  In such a rack and pinion type steering device, a rack guide that slidably supports a rack bar that moves linearly by steering operation has a clearance (clearance) between the rack bar and the inner peripheral surface of the housing. It is mounted so that it can move freely in the direction perpendicular to the direction, that is, in the axial direction. However, if there is such a gap, the rack guide will swing due to the direct movement of the rack bar, and the rack guide will collide with the housing. Noises such as noise may occur. In addition, since the rack guide and the housing are usually made of metal, if the gap is made minute so as to eliminate the above-described swing, the rack guide and the housing are so-called between the rack guide and the housing by sliding in the axial direction of the rack guide with respect to the housing. There is a possibility that “togane” may occur, and when such “togane” occurs, problems such as an increase in frictional resistance and an axial movement of the rack guide due to adhesive wear are caused.

  Therefore, it has been proposed to attach an elastic ring to the rack guide so that the rack guide does not come into direct contact with the housing. In the rack and pinion type steering device according to such a proposal, the problem caused by "Tomogane" is eliminated. However, as a result of the elastic ring attached to the rack guide completely closing the minute gap that functions as an air passage between the inner peripheral surface of the housing and the rack guide, the rack guide moves with respect to the housing through the minute gap. As a result, it is difficult for the air to flow, and the space between the housing and the end surface of the rack guide becomes a sealed air chamber. This sealed air chamber may hinder the rapid movement of the rack guide relative to the housing.

  Further, it has been proposed to mount a buffer member made of synthetic resin in the housing to eliminate direct contact of the rack guide with the housing. In the rack and pinion type steering device according to such a proposal, the buffer member and the rack As a result of providing a gap between the guide and the rack guide, the rack guide dances due to the gap, and a tight engagement between the pinion and the rack bar rack teeth is not ensured. Sound may occur.

  The present invention has been made in view of the above-mentioned points. The object of the present invention is to eliminate the occurrence of abnormal noise such as collision noise due to rocking and to eliminate the disadvantages of "Tomogane". In addition, it is possible to prevent a sealed air chamber from being formed between the housing and the rack guide, and it is possible to prevent the rack guide from being danced. It is an object of the present invention to provide a rack guide capable of immediately responding to a displacement in an orthogonal direction and a rack and pinion type steering apparatus including such a rack guide.

  A rack guide according to the present invention includes a rack guide main body and a sliding contact member made of synthetic resin fitted to the rack guide main body, wherein the rack guide main body is a housing of a rack and pinion type steering device. A cylindrical outer peripheral surface facing the cylindrical inner peripheral surface with a gap, a plurality of grooves extending in the axial direction on the outer peripheral surface, and one end surface in the axial direction. The sliding surface member has a curved portion seated on the concave surface of the rack guide body and a plurality of gap holding portions formed integrally with the curved portion. The curved portion has a sliding contact surface that slidably contacts the rack bar, and each gap holding portion projects from the outer peripheral surface of the rack guide body in the radial direction. Fits into the groove and diameter It is adapted to slidably contact with the cylindrical inner peripheral surface of the housing of the rack-pinion type steering apparatus in the projecting end surface protruding in direction.

  According to the rack guide of the present invention, since the gap holding portion of the sliding contact surface member made of synthetic resin comes into contact with the cylindrical inner peripheral surface of the housing at its protruding end surface, the rack guide to the housing As a result of eliminating the direct contact of the main body, it is possible to eliminate the occurrence of abnormal noise such as a collision sound due to a collision with the housing due to the swinging of the rack guide main body, and to eliminate the inconvenience caused by “Togane” The gap between the projecting end faces adjacent to each other in the direction around the axis of the gap holding portion communicates the gap on one end face side in the axial direction of the rack guide body and the gap on the other end face side in the axial direction of the rack guide body. Since a passage is formed, the inside of the housing on one end face side in the axial direction of the rack guide body and the inside of the housing on the other end face side in the axial direction of the rack guide body are mutually connected. It is possible to communicate with each other so that a sealed air chamber is not generated between the housing and the other axial end surface of the rack guide, and each gap holding portion is fitted in a corresponding groove of the rack guide body. Therefore, it is difficult for the rack guide to dance, and thus it is possible to immediately respond to an axial displacement that is a direction orthogonal to the linear movement direction of the rack bar.

  The sliding surface member has an appropriate rigidity so that the gap holding portion can hold a gap between the cylindrical inner peripheral surface of the housing and the cylindrical outer peripheral surface of the rack guide main body even when the rack guide main body swings. In addition, the sliding surface of the curved portion is such that the linear movement of the rack bar can be guided and supported with low friction, and the protruding end surface of the gap holding portion is moved in the axial direction of the rack guide body to It is preferable that it has a low friction characteristic that can slide with a low friction with the surface, and has an appropriate elasticity so that the protruding end surface of the gap holding portion elastically contacts the inner peripheral surface of the housing. Examples of the synthetic resin that is a material for forming the contact member include polyacetal, polyamide, polyurethane, and polyester elastomer.

  In a preferred example, the rack guide body has a recess provided on the other end surface in the axial direction, and a through hole provided in the central portion and extending in the axial direction in communication with the recess. The contact surface member has a protrusion that is attached to the through hole of the rack guide main body and is formed integrally with the curved portion, where the protrusion is a blocking means for preventing the protrusion from the through hole, For example, you may have a huge part. Such through-holes and protrusions are for integrally joining the sliding contact surface member and the rack guide main body to each other, but instead of or together with such through-holes and protrusions, a claw is provided at the end of the gap holding portion. The claw portion may be hooked on the other end surface of the rack guide main body so that the sliding contact surface member and the rack guide main body are integrally coupled to each other.

  A plurality of, for example, two grooves of the rack guide body may be provided, but in a preferred example, at least three grooves are provided at substantially equal angular intervals in the direction around the axis. In this case, each gap holding portion is fitted in a corresponding groove of the rack guide body. In the rack guide of such an example, the rack guide main body is evenly held in the direction around the axis on the cylindrical inner peripheral surface of the housing, so that direct contact of the rack guide main body with the housing is more reliably eliminated. Can do.

  A rack and pinion type steering device according to the present invention includes a rotatable pinion, a rack bar that has rack teeth meshing with the pinion and is directly movable, the housing that rotatably supports the pinion, and a sliding rack bar. The rack guide of the above-mentioned various aspects supported freely, and the elastic means which presses this rack guide toward a pinion are provided.

  The concave surface of the one end surface in the axial direction of the rack guide body may define the bottom surface of the recess formed in the one end surface. In the case of such a concave surface, the sliding contact seated on the concave surface is possible. As a result of positioning the curved portion of the surface member by the recess, it is possible to eliminate the inconvenience that the curved portion is displaced with respect to the concave surface, but such positional displacement prevention may be performed by the gap holding portion. In this case, the curved portion may be simply placed on the concave surface and seated without forming a recess for fitting the curved portion on one end surface of the rack guide body in the axial direction.

  According to the present invention, it is possible to eliminate the occurrence of abnormal noise such as a collision sound due to rocking, to eliminate the disadvantages of `` Togane '', and to prevent a sealed air chamber from being generated between the housing and A rack guide which can hardly cause the rack guide to be danced and thus can quickly move in the axial direction with respect to the housing and can immediately respond to a displacement in a direction perpendicular to the linear movement direction of the rack bar, and the like. A rack and pinion type steering device including a rack guide can be provided.

FIG. 1 is a cross-sectional explanatory diagram of a preferred example of an embodiment according to the present invention. FIG. 2 is an explanatory front view of the rack guide shown in FIG. FIG. 3 is an explanatory plan view of the rack guide shown in FIG. 4 is an explanatory plan view of the rack guide body shown in FIG. FIG. 5 is an explanatory front view of the rack guide main body shown in FIG. 6 is an explanatory bottom view of the rack guide body shown in FIG. 7 is a cross-sectional explanatory view taken along line VII-VII shown in FIG. FIG. 8 is an explanatory plan view of the sliding contact surface member shown in FIG. FIG. 9 is an explanatory front view of the sliding surface member shown in FIG. FIG. 10 is an explanatory bottom view of the sliding surface member shown in FIG. FIG. 11 is a partial cross-sectional explanatory diagram of the example shown in FIG.

  Next, embodiments of the present invention will be described in more detail based on preferred examples shown in the drawings. The present invention is not limited to these examples.

  In FIG. 1, a rack and pinion type steering device 1 of this example has a pinion 2 that is rotatable in the R direction and a rack tooth 3 that meshes with the pinion 2, and linearly moves in the A direction (a direction orthogonal to the paper surface in FIG. 1). A flexible rack bar 4, a housing 5 that rotatably supports the pinion 2 in the R direction, a rack guide 6 that slidably supports the rack bar 4, and elastic means that presses the rack guide 6 toward the pinion 2. 7.

  A pinion shaft 11 integrally provided with a pinion 2 is supported by a housing 5 via a ball bearing 12 so as to be rotatable in the R direction about the axis of the pinion shaft 11 and rotated in the R direction by a steering operation. It has come to be.

  The rack bar 4 that is directly moved in the A direction through the meshing of the pinion 2 and the rack teeth 3 by the rotation of the pinion 2 in the R direction has a semi-cylindrical shape on the side opposite to the surface on which the rack teeth 3 are provided. It has a sliding surface 15 made of a convex surface.

  The housing 5 through which the rack bar 4 penetrates in the A direction has a housing main body portion 16 to which the ball bearings 12 are attached, a housing inner body portion 16 and a cylindrical inner peripheral surface 17. A cylindrical portion 18 and a lid portion 20 screwed to one end of the cylindrical portion 18 via a screw portion 19. The lid portion 20 includes a lock nut 21 screwed to the lid portion 20. It is being fixed to the cylindrical part 18 by.

  The rack guide 6 disposed in the cylindrical portion 18 of the housing 5 includes a rack guide main body 25 and a sliding surface made of synthetic resin fitted to the rack guide main body 25 as shown in FIGS. Member 26.

  The rack guide main body 25 made of a rigid metal such as aluminum has a cylindrical shape that faces the inner peripheral surface 17 of the cylindrical portion 18 of the housing 5 with a gap 31 as shown in FIGS. The outer circumferential surface 32 and four grooves provided on the outer circumferential surface 32 so as to extend in the axial direction, that is, in the B direction, and in this example, are arranged at substantially equal angular intervals of 90 ° in the direction around the axis. 33, a concave surface 35 provided on one end surface 34 in the B direction, a cylindrical recess 37 provided on the other end surface 36 in the B direction, and a central portion extending in the B direction in communication with the concave portion 37. And a through-hole 38 provided.

  Each groove 33 extends from the one end surface 34 to the other end surface 36 in the B direction, and the concave surface 35 defines the bottom surface of the recess 39 formed in the one end surface 34 of the rack guide body 25.

  As shown in FIGS. 8 to 10, the slidable contact surface member 26 is formed integrally with the curved portion 45, which is seated on the concave surface 35 of the rack guide body 25 and fitted into the concave portion 39. A plurality of gaps, in this example, four gap holding portions 46 arranged at substantially equal angular intervals of 90 ° in the direction around the axis, and the curved portion are mounted in the through holes 38 of the rack guide body 25. 45 and a protrusion 47 formed integrally with 45.

  The curved plate-like curved portion 45 has a slidable contact surface 51 formed of a semi-cylindrical concave surface that slidably contacts the sliding surface 15 of the rack bar 4, and each gap holding portion 46 has a radial direction. In FIG. 11, the cylindrical portion 18 is protruded from the outer peripheral surface 32 of the rack guide main body 25 so as to be fitted in the corresponding groove 33 of the rack guide main body 25 and protruded in the radial direction as shown in FIG. In addition, each gap holding portion 46 is slidably in contact with the inner peripheral surface 17 of each of the inner peripheral surface 17 and the rack end portion 53 and the one end surface 53 in the B direction which are flush with the sliding contact surface 51 of the bending portion 45. A protrusion 47 formed integrally with the curved portion 45 on the opposite surface of the sliding contact surface 51 extends in the B direction with the other end surface 54 in the B direction that is flush with the other end surface 36 of the guide body 25. The enormous part 5 which prevents the escape from the through hole 38 The enormous portion 55 is provided with a cross slit 56 for facilitating the insertion of the projection 47 into the through hole 38, and the enormous portion 55 is formed on one end surface of the recess 37 in the B direction. Is hooked to the annular inner wall 57 of the rack guide body 25.

  The elastic means 7 is in contact with the annular inner wall 57 in the recess 37 at one end, and is compressed in contact with the lid portion 20 at the other end, and is arranged between the rack guide body 25 and the lid portion 20. The coil spring 61 elastically presses the sliding contact surface 51 of the curved portion 45 against the sliding surface 15 of the rack bar 4 via the rack guide main body 25.

  In the rack and pinion type steering device 1 described above, when the pinion shaft 11 is rotated in the R direction by the steering operation, the rack bar 4 is linearly moved in the A direction through the meshing of the pinion 2 and the rack teeth 3. A steering operation is transmitted to the wheels of the automobile connected to the rack bar 4. In the rack and pinion type steering apparatus 1, the rack guide 6 is brought into contact with the sliding surface 15 of the rack bar 4 at the sliding contact surface 51 to guide the linear movement of the rack bar 4 in the A direction and the elastic force by the elastic means 7. Thus, the engagement of the pinion 2 and the rack teeth 3 is ensured, and the cylindrical portion of the housing 5 in the B direction follows the slight displacement in the B direction of the rack bar 4 and the elastic means 7 expands and contracts. 18 to move.

  By the way, according to the rack guide 6, since the gap holding portion 46 of the sliding contact surface member 26 made of synthetic resin comes into contact with the inner peripheral surface 17 of the cylindrical portion 18 at the protruding end surface 52, the housing 5 As a result of eliminating the direct contact of the rack guide main body 25 with the cylindrical portion 18, abnormal noise such as a collision sound due to the collision with the cylindrical portion 18 of the housing 5 due to the swing of the rack guide main body 25 is generated. In addition to eliminating the inconvenience caused by “togane”, the gap 31 between the projecting end faces 52 adjacent to each other in the direction around the axis of the gap holding portion 46 is located on the one end face 34 side of the rack guide body 25 in the B direction. Since the passage 65 is formed to communicate the gap 31 of the rack guide body 25 with the gap 31 on the other end face 36 side in the B direction of the rack guide body 25, the B direction of the rack guide body 25 is formed. The housing 5 on one end face 34 side of the rack guide body 25 can be communicated with the housing 5 on the other end face 36 side in the B direction of the rack guide body 25, that is, the space 66 between the end face 36 and the lid portion 20. 5 and the other end surface 36 in the B direction of the rack guide 6, and a sealed air chamber is not generated, and each gap holding portion 46 is fitted in the corresponding groove 33 of the rack guide body 25. For this reason, the rack guide 6 can be hardly danced, and thus can immediately respond to the displacement of the rack bar 4 in the direction B, which is the direction orthogonal to the direction A, which is the linear motion direction. As a result, the rack guide 6 can immediately move in the B direction with respect to the cylindrical portion 18 of the housing 5 following the slight displacement of the rack bar 4 in the B direction. As a result, the pinion 2 and the rack teeth 3 When Snug meshing always has ensured, it may eliminate the generation of abnormal noise due to teeth hitting the pinion 2 and the rack teeth 3.

DESCRIPTION OF SYMBOLS 1 Rack and pinion type steering device 2 Pinion 3 Rack tooth 4 Rack bar 5 Housing 6 Rack guide 7 Elastic means 17 Inner peripheral surface 18 Cylindrical portion 31 Clearance 25 Rack guide main body 26 Sliding surface member 32 Outer peripheral surface 33 Groove 34 One end surface 45 Curve 46

Claims (5)

  A rack guide body and a synthetic resin sliding contact surface member fitted to the rack guide body, the rack guide body having a clearance on a cylindrical inner peripheral surface of a housing of the rack and pinion type steering device. It has a cylindrical outer peripheral surface that faces each other, a plurality of grooves provided on the outer peripheral surface so as to extend in the axial direction, and a concave surface provided on one end surface in the axial direction. The contact surface member has a curved portion seated on the concave surface of the rack guide main body and a plurality of gap holding portions formed integrally with the curved portion, and the curved portion slides on the rack bar. It has sliding contact surfaces that come into contact freely, and each gap holding portion is fitted in a corresponding groove of the rack guide body so as to protrude from the outer peripheral surface of the rack guide body in the radial direction and radially At the protruding end surface protruding at the rack Anion formula slidably contacting manner going on rack guide in a cylindrical inner peripheral surface of the housing of the steering system.   The rack guide body has a recess provided on the other end surface in the axial direction, and a through hole provided in the central portion and extending in the axial direction in communication with the recess. The rack guide according to claim 1, further comprising a protrusion that is mounted in the through hole of the rack guide main body and is integrally formed with the curved portion.   The rack guide according to claim 2, wherein the protrusion has an enormous portion that prevents the protrusion from coming through the through hole.   At least three grooves of the rack guide main body are arranged at substantially equal angular intervals in the direction around the axis, and each gap holding portion is fitted in a corresponding groove of the rack guide main body. Item 4. The rack guide according to any one of Items 1 to 3.   5. The rotatable pinion, the rack bar having a rack tooth meshing with the pinion and freely movable, the housing for rotatably supporting the pinion, and the rack bar slidably supported. A rack and pinion type steering device comprising: the rack guide according to any one of the above items; and elastic means for pressing the rack guide toward the pinion.

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