JP2015196419A - Rack guide and gear mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack guide capable of stably supporting a rack bar with excellent wear resistance and low frictional resistance and a gear mechanism using the rack guide.SOLUTION: A rack guide 30 includes a columnar base section 31 and a rack guide sheet 32 fixed to one end face 38B side of the base section 31. The rack guide sheet 32 has a layer structure including a metal plate 321 and a rack bar support layer 322 for supporting a back face 22 of a rack bar 20. The rack bar support layer 322 includes a porous sintered metal layer 324 laminated on one surface of the metal plate 321 and a resin layer 323 which is formed of resin 3231 filled in pores in the porous sintered metal layer 324 and covers a part of a front face of the porous sintered metal layer 324. Both of metal 3241 of the porous sintered metal layer 324 and resin 3231 of the resin layer 323 are exposed at an appropriate ratio on a front face 325 of the rack bar support layer 322. The front face 325 functions as a sliding surface 33 of the rack guide sheet 32.

Description

  The present invention relates to a rack guide that presses a rack bar against a pinion via a rack guide sheet (support yoke sheet) in a rack and pinion used in an automobile steering device or the like, and in particular, has a slidability and wear resistance. The present invention relates to an excellent rack guide (support yoke) for both and a gear mechanism using the same.

  In a rack and pinion used in an automobile steering device, etc., it is arranged in the rack case on the back side of the rack bar (the arc surface on the opposite side of the rack gear) and presses the rack bar against the pinion while guiding it in the axial direction. As a rack guide, for example, a rack guide described in Patent Document 1 is known.

  The rack guide includes a rack guide body that is biased toward the back of the rack bar by the elastic force of a coil spring inserted between the rack case cap and a space between the back of the rack bar and the rack guide body. And a rack guide sheet that slidably supports the back surface of the rack bar.

  The rack guide sheet is a multilayered sheet material that is curved following the shape of the back surface of the rack bar, and is symmetrical about the center line of the cross section perpendicular to the axial direction of the rack bar as a sliding surface that supports the back surface of the rack bar. And has a concave surface including two circular arc surfaces. Each of these two arc surfaces is a circle having a radius of curvature larger than the cross-sectional shape of the back surface of the rack bar with the center of curvature at the position on the rack gear side than the center of curvature of the cross-sectional shape (arc shape) of the back surface of the rack bar. It has an arcuate cross-sectional shape. Then, the back surface of the rack bar contacts these two arc surfaces linearly or in a strip shape at a symmetrical position with respect to the center line of the cross section perpendicular to the axial direction of the rack bar. A boss for fixing the rack guide sheet to the rack guide body is formed on the back surface (the surface opposite to the sliding surface) of the rack guide sheet.

  The rack guide sheet of such a rack guide impregnates the porous sintered metal layer, the porous sintered metal layer formed on one surface of the thin steel sheet, and the porous sintered metal layer. It is formed by molding a multilayer sheet material having a three-layer structure with a synthetic resin layer covering the entire surface of the metal layer. Specifically, the multi-layer sheet material is bent by a press molding process so that the surface of the synthetic resin layer becomes a sliding surface (bending process), and a boss is formed in the central region (drawing process).

  On the other hand, the rack guide body is formed with a concave portion having a curved shape following the shape of the back surface of the rack guide sheet, and the rack guide sheet is accommodated inside the concave portion without a gap. Further, a through hole for fixing the rack guide sheet is formed in the central region of the recess of the rack guide, and the rack guide sheet is fixed to the rack guide by press-fitting a boss into the through hole.

  In such a structure, the contact position of the back surface of the rack bar by the sliding surface of the rack guide sheet (the contact position between the two arc surfaces and the back surface of the rack bar) is the center of the cross section perpendicular to the axial direction of the rack bar. The position of the rack bar that is reciprocated by the operation of the steering wheel is set to a position of 50 degrees or less from the line and the clearance between both edges of the sliding surface and the back of the rack bar is set to 0.02 to 0.2 mm. Steering wheel operability is improved by preventing swinging and increasing sliding frictional resistance.

JP 2001-010510 A

  However, when the synthetic resin layer constituting the sliding surface of the rack guide sheet is worn by sliding with the rack bar, the rack guide (the rack guide body of the rack guide main body) and the rack guide that is biased by the coil spring are correspondingly worn. For example, when a large load is applied to the rack bar due to the impact from the road surface to the tire, the rack bar rattles due to the reaction of the coil spring, and the difference between the teeth of the pinion gear and the rack gear occurs. Sound may be produced.

  In addition, when the rack guide sheet is press-molded from one composite sheet material, the resin may flow or deform during processing, and the thickness of the synthetic resin layer may vary. For example, when the boss is molded, the resin pushed by pressing the mold rises around the edge of the boss, and a raised portion (convex portion) of the resin may be formed at the bottom of the sliding surface of the guide rack sheet. . If the back surface of the rack bar comes into contact with such a raised portion of the resin, the back surface of the rack bar is not stably supported at a predetermined position on the two arc surfaces formed on the sliding surface of the rack guide sheet. There is a possibility that the steering performance of the steering wheel is lowered.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rack guide capable of stably supporting a rack bar, capable of stably supporting a rack bar having excellent wear resistance and low friction resistance, and The object is to provide a gear mechanism using this.

  In order to solve the above problems, in the present invention, the rack bar is slidably supported by the sliding surface that maintains the state where the resin and the metal are dispersedly exposed.

For example, according to the present invention, a rack bar formed with a rack gear that meshes with a pinion gear is slidably supported from the opposite side of the rack gear, and the rack bar that moves according to the rotation of the pinion gear is supported by the rack bar. A rack guide for guiding in the axial direction,
A guide bar support layer including a metal having a plurality of voids and a resin filled in the voids of the metal,
The guide bar support layer has a surface exposed by mixing the metal and the resin as a sliding surface that supports the rack bar so as to be slidable in the axial direction of the rack bar.

  According to the present invention, since the sliding surface that slidably supports the rack bar in a state where the resin and the metal are exposed is formed, the wear resistance is improved while maintaining the sliding property of the sliding surface. In addition, the shape accuracy of the sliding surface of the rack guide sheet can be improved, and the rack bar can be stably supported.

FIG. 1 is a cross-sectional view of a gear mechanism 1 of a steering device according to an embodiment of the present invention. 2A, 2B, 2C, and 2D are an external view, a plan view, a front view, and a bottom view of the rack guide 30, and FIG. 2E is a view of FIG. It is AA sectional drawing. 3A is a diagram for explaining the shape of the rack guide sheet 32, and FIG. 3B is a diagram for explaining a cross-sectional structure of the rack guide sheet 32. As shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. For convenience of the following description, the axial direction of the rack bar 20 (moving direction of the rack bar 20) is the X direction, the pressing direction of the rack gear 21 against the pinion gear 11 is the Z direction, and the direction perpendicular to the X and Z directions is The Y direction is defined, and these directions are appropriately displayed in each figure.

  FIG. 1 is a cross-sectional view of the gear mechanism 1 of the steering device according to the present embodiment.

  The steering apparatus according to the present embodiment has a rack and pinion type gear mechanism 1 that converts the rotational motion of the steering shaft into linear motion and transmits this linear motion to a link mechanism that changes the direction of the wheels. .

  As illustrated, the gear mechanism 1 includes a pinion shaft 10 in which a pinion gear 11 is formed, a rack bar 20 in which a rack gear 21 that meshes with the pinion gear 11 is formed, a bearing 50 that rotatably supports the pinion shaft 10, and a pinion A rack guide 30 that guides the rack bar 20 that reciprocates in the X direction as the gear 11 rotates, a coil spring 40 that biases the rack guide 30 in the Z direction so as to press the rack gear 21 against the pinion gear 11, and these components It has a housing 70 and a cap 60 in which 10 to 50 are incorporated. As will be described later, an annular elastic member (for example, an O-ring) 80 is further provided between the inner wall surface 78 of the cylinder case portion of the housing 70 and the outer peripheral surface of the base portion 31 of the rack guide 30. Also good.

  The pinion shaft 10 is a columnar member arranged so that the axis O1 is inclined with respect to the Y direction. For example, a helical gear is formed as the pinion gear 11 on the outer peripheral surface 12 of the pinion shaft 10. The pinion gear 11 is accommodated in a pinion gear accommodating portion 73 of the housing 70, and the pinion shaft 10 is supported on the housing 70 so as to be rotatable around the axis O1 via the bearing 50 at positions on both sides of the pinion gear 11. Has been. Also, one end 13 of the pinion shaft 10 protrudes from the opening 74 formed in the housing 70 to the outside of the pinion gear housing 73 and is connected to a steering shaft (not shown). Thereby, the pinion gear 11 rotates in conjunction with the steering shaft that rotates in accordance with the operation of the steering wheel.

  The rack bar 20 is a cylindrical member disposed along the X direction, and although not shown, both ends thereof are connected to a link mechanism that changes the direction of the wheel via a ball joint. The plurality of teeth constituting the rack gear 21 are formed side by side in the X direction on the outer peripheral surface of the rack bar 20, and mesh with the teeth of the pinion gear 11 at a predetermined meshing position in the pinion gear accommodating portion 73 of the housing 70. Yes. The rack bar 20 has an arcuate surface opposite to the rack gear 21 (an outer peripheral surface facing the sliding surface 33 of the rack guide 30 and having an arcuate YZ cross-sectional shape: hereinafter referred to as a back surface 22). The sliding surface 33 is slidably supported. When the pinion shaft 10 is rotated together with the steering shaft, the rack bar 20 is guided by the sliding surface 33 of the rack guide 30 and reciprocated in the X direction by the meshing of the pinion gear 11 and the rack gear 21 to swing the link mechanism. Let Thereby, the direction of a wheel changes according to operation of a steering wheel.

  The housing 70 includes a cylindrical rack case portion 71 disposed along the X direction, and a cylindrical cylinder case portion 72 protruding from the outer periphery of the rack case portion 71 in the Z direction.

  Inside the rack case part 71, the rack bar 20 is accommodated so as to be movable in the X direction. Further, inside the rack case portion 71, as a pinion gear accommodating portion 73, a chamber is provided that obliquely crosses the rack gear 21 at a predetermined meshing position. As described above, the pinion gear housing 73 accommodates the pinion gear 11 and the bearing 50 that rotatably holds the pinion shaft 10 at a position where the pinion gear 11 meshes with the rack gear 21 at a predetermined meshing position. Has been. The rack case portion 71 has an opening 74 that connects the pinion gear housing portion 73 and the outside toward the steering shaft (not shown), and is connected to the steering shaft (not shown). The one end 13 of the projection protrudes from the opening 74 to the outside of the pinion gear housing 73.

  On the other hand, the cylinder case portion 72 is formed integrally with the rack case portion 71 so as to be positioned on the opposite side of the pinion gear 11 with respect to the rack bar 20, and the inside of the cylinder case portion 72 and the rack case portion 71 are formed. The inside is connected via a circular opening 75 facing the pinion gear 11 in the pinion gear housing 73. In addition, a screw part 77 for fixing the cap 60 is formed on the inner wall surface 78 of the open end 76 of the cylinder case part 72.

  The rack guide 30 has one end surface (one end surface 38B of the base portion 31 in FIG. 2) provided with a sliding surface 33 slidably supporting the back surface 22 of the rack bar 20 on the back surface 22 side of the rack bar 20. Toward the inside of the cylinder case portion 72 so as to be slidable in the Z direction, and on the opposite side of the pinion gear 11 with respect to the rack bar 20 (the rear surface 22 of the rack bar 20 at the position where the pinion gear 11 and the rack gear 21 are engaged). Side). Further, a spring guide (bottom hole) 35 for the coil spring 40 is provided on the other end face of the rack guide 30 (the other end face 38A of the base portion 31 in FIG. 2). The detailed structure of the rack guide 30 will be described later.

  The coil spring 40 is accommodated in the cylinder case portion 72 of the housing 70 so as to be inserted into the spring guide 35 of the rack guide 30. When the cap 60 is fitted into the open end portion 76 of the cylinder case portion 72 of the housing 70, the coil spring 40 is positioned between the rack guide 30 and the inner side surface 61 of the cap 60 in the cylinder case portion 72 of the housing 70. It is done. Since the natural length of the coil spring 40 is longer than the depth of the spring guide 35 of the rack guide 30, one end 41 of the coil spring 40 extends from the spring guide 35 of the rack guide 30 to the inner surface (cylinder case portion 72) of the cap 60. The one surface directed toward the inside) protrudes to the 61 side.

  The cap 60 has a disk shape that can be fitted into the open end 76 of the cylinder case portion 72, and a screw portion 62 is formed on the outer periphery of the cap 60. After the rack guide 30 is inserted into the cylinder case portion 72 of the housing 70 and the coil spring 40 is accommodated in the spring guide 35 of the rack guide 30, the screw portion 62 of the cap 60 is opened to open the cylinder case portion 72. By screwing into the threaded portion 77 of the end portion 76, the cap 60 is fixed to the open end portion 76 of the cylinder case portion 72 to block the cylinder case portion 72, and the inner surface 61 of the cap 60 and the spring guide of the rack guide 30 are also closed. The coil spring 40 is compressed between the bottom surface 351 of 35. As a result, the rack bar 20 is urged toward the pinion gear 11 by the restoring force of the coil spring 40 and the rack gear 21 is pressed against the pinion gear 11, thereby preventing tooth separation at the meshing position of the rack gear 21 and the pinion gear 11. Is done.

  Next, the detailed structure of the rack guide 30 will be described.

  2A, 2B, 2C, and 2D are an external view, a plan view, a front view, and a bottom view of the rack guide 30, and FIG. 2E is a view of FIG. It is AA sectional drawing.

  As shown in the figure, the rack guide 30 includes a cylindrical base portion 31 formed of a metal material having excellent durability and impact resistance, and a rack guide sheet 32 fixed to one end surface 38B side of the base portion 31. And have.

  A hole with a bottom is formed as a spring guide 35 on the other end surface 38 </ b> A of the base portion 31. As described above, the coil spring 40 is inserted into the spring guide 35 and is screwed between the bottom surface 351 of the spring guide 35 and the inner side surface 61 of the cap 60 by screwing the cap 60 into the open end 76 of the cylinder case portion 72. It is compressed with.

  In a central region of one end surface 38B of the base portion 31 (region surrounding the axis O2 of the base portion 31), a groove portion having a curved shape following the shape of the back surface (surface on the base portion 31 side) 326 of the rack guide sheet 32. 37 is formed. Further, a sheet fixing through hole 36 for press-fitting the boss portion 34 of the rack guide sheet 32 is formed in a central region of the groove portion 37 (region surrounding the axis O2 of the base portion 31).

  One or more circumferential grooves 391 are formed on the outer peripheral surface 39 of the base portion 31, and an annular elastic member such as an O-ring having a wire diameter larger than the depth dimension of the grooves 391 inside the groove 391. 80 may be embedded. As a result, the annular elastic member 80 that surrounds the base portion 31 in the circumferential direction is compressed between the inner wall surface 78 of the cylinder case portion 72 of the housing 70 and the outer peripheral surface 39 of the base portion 31. Shaking of the rack guide 30 is suppressed.

  On the other hand, the rack guide sheet 32 is a multilayer sheet material that is curved in accordance with the curved surface shape of the back surface 22 of the rack bar 20, and can slide on the back surface 22 of the rack bar 20 as an opposing surface of the back surface 22 of the rack bar 20. And has a sliding surface 33 to be supported.

  FIG. 3A is a diagram for explaining the shape of the rack guide sheet 32.

  As shown in the figure, the sliding surface 33 has a concave shape including two circular arc surfaces (YZ cross-sectional surface having a circular arc shape) 33A and 33B that are symmetrical with respect to the center line O3 of the YZ cross-section of the rack bar 20. Yes. The YZ cross-sections of these two arcuate surfaces 33A and 33B are located symmetrically with respect to the center line O3 of the YZ cross-section of the rack bar 20, which is closer to the rack gear 21 than the center of curvature O of the YZ cross-sectional shape of the back surface 22 of the rack bar 20. , OB is the center of curvature, and has an arc shape in contact with the back surface 22 of the rack bar 20 at positions TA and TB symmetrical with respect to the center line O3. For this reason, the back surface 22 of the rack bar 20 is in contact with the two arcuate surfaces 33A and 33B in a linear or belt-like region along the X direction that is substantially symmetric with respect to the center line O3 of the YZ cross section.

  On the back surface 326 of the rack guide sheet 32, a boss portion 34 protruding to the opposite side of the sliding surface 33 is formed. The rack guide sheet 32 is accommodated inside the groove portion 37 of the base portion 31 and is fixed to the base portion 31 by press-fitting the boss portion 34 into the sheet fixing through hole 36 of the base portion 31.

  FIG. 3B shows a cross-sectional structure of the rack guide sheet 32.

  As illustrated, the rack guide sheet 32 has a layered structure including a metal plate 321 such as a thin steel plate and a rack bar support layer 322 that supports the back surface 22 of the rack bar 20. Here, the rack bar support layer 322 includes a porous sintered metal layer 324 formed by sintering the metal 3241 laminated on one surface of the metal plate 321, and a porous sintered metal layer 324. And a resin layer 323 that is formed of a resin 3231 such as PTFE filled in the pores (voids) and covers a part of the surface of the porous sintered metal layer 324. Therefore, both the metal 3241 of the porous sintered metal layer 324 and the resin 3231 of the resin layer 323 are mixedly exposed on the surface 325 of the rack bar support layer 322 at an appropriate ratio. The surface 325 of the rack bar support layer 322, in other words, the surface of the resin layer 323 in which the metal 3241 and the resin 3231 are dispersed and exposed at an appropriate ratio is caused to function as the sliding surface 33 of the rack guide sheet 32. Thus, the low friction resistance of the sliding surface 33 of the rack guide sheet 32 is maintained by the exposed resin 3231, and the entire surface of the porous sintered metal layer is covered with the resin layer by the exposed metal 3241. As compared with the rack guide sheet, the wear resistance of the sliding surface 33 of the rack guide sheet 32 can be improved. The exposure ratio of the resin 3231 and the metal 3241 on the sliding surface 33 of the rack guide sheet 32 is appropriately determined according to the sliding performance and wear resistance required for the sliding surface 33 of the rack guide sheet 32. . For example, the exposure ratio of the metal 3241 on the sliding surface 33 of the rack guide sheet 32 can be about 20% or less.

  The rack guide sheet 32 having such a structure is, for example, a porous plate formed by sintering a metal plate 321 and the above-described rack bar support layer 322 (metal 3241 laminated on one surface of the metal plate 321). A rack including a sintered metal layer 324 and a resin layer 323 formed of a resin 3231 filled in pores in the porous sintered metal layer 324 and covering a part of the surface of the porous sintered metal layer 324 Bar support layer 322), and is produced by press molding of a multilayer sheet material having a layered structure. Specifically, the multi-layer sheet material is bent (bending process) so that the surface 325 of the rack bar support layer 322 becomes the sliding surface 33 of the rack guide sheet 32 by press molding, and a boss is formed in the center region. The part 34 is formed (drawing process). Here, on the porous sintered metal layer 324, a resin layer that may cause variations in thickness during press molding is formed so as to cover the entire surface of the porous sintered metal layer 324. Therefore, even if the rack guide sheet 32 has a portion such as the boss portion 34, the sliding surface 33 of the rack guide sheet 32 can be accurately formed by press molding. For example, when the boss portion 34 is formed, the resin is not pushed by the pressing of the mold, so that the resin bulge portion is formed in the region 341 around the edge of the boss portion 34 in the sliding surface 33 of the rack guide sheet 32. Is not formed. Accordingly, the position at which the rack bar 20 is supported by the rack guide seat 32 (the contact position between the rear surface 22 of the rack bar 20 and the sliding surface 33 of the rack guide seat 32) is stabilized, so that the steering wheel system has the desired steering performance. It can be demonstrated.

  In addition, when there is a possibility that a resin bulge portion is formed in the region 341 around the edge of the boss portion 34, the rack bar 20 is placed on such a resin bulge portion in order to prevent a reduction in steering performance of the steering wheel. The offset amount r of the curvature centers OA and OB of the two arcuate surfaces 33A and 33B from the axis O of the rack bar 20 (the center of curvature of the YZ cross section of the back surface 22 of the rack bar 20) O is increased so that the back surface 22 does not contact. However, in this case, a gap between the rear surface 22 of the rack bar 20 and both edges of the sliding surface 33 of the rack guide sheet 32 is widened, which makes it difficult to prevent the rack bar 20 from swinging. Become. On the other hand, in the present embodiment, as described above, since the formation of the resin bulge portion on the sliding surface 33 of the rack bar 20 is prevented, two arcs from the axis O of the rack bar 20 are prevented. The offset amount r of the centers of curvature OA and OB of the surfaces 33A and 33B can be reduced to, for example, 1 mm or less. As a result, the swing of the rack bar 20 that reciprocates by the operation of the steering wheel is reliably suppressed by the two arc surfaces 33A and 33B, and the pinion gear 11 and the rack gear 21 can be stably meshed. Can be prevented, and the steering performance of the steering wheel can be further improved.

  The embodiment of the present invention has been described above.

  As described above, according to the present embodiment, in the gear mechanism 1, the surface of the resin layer 323 where the resin 3231 and the metal 3241 are exposed at an appropriate ratio is slidably supported by the back surface 22 of the rack bar 20. Since it functions as the moving surface 33, the porous sintered metal layer is porously sintered with the resin layer while maintaining the low friction resistance of the sliding surface 33 as in the case where the entire surface of the porous sintered metal layer is covered with the resin layer. The wear resistance of the sliding surface 33 can be improved as compared with the case where the entire surface of the metal layer is covered. As a result, the smooth reciprocation of the rack bar 20 is maintained, and the driver can smoothly steer the steering wheel over a long period of time, and the occurrence of rattling of the rack bar 20 due to the reaction of the coil spring 40 is prevented. It is possible to prevent abnormal noise between the teeth of the pinion gear 11 and the teeth of the rack gear 21.

  The rack guide sheet 32 having such a sliding surface 33 includes, for example, a metal plate 321 and a porous sintered metal layer 324 formed by sintering a metal 3241 laminated on one surface of the metal plate 321. And a multi-layer sheet material having a resin layer 323 covering a part of the surface of the porous sintered metal layer 324, which is formed by a resin 3231 filled in the pores in the porous sintered metal layer 324. Can be produced. Since the resin layer that may cause variations in thickness during the press molding process is not formed on the entire porous sintered metal layer 324 of the multilayer sheet material used here, the rack guide sheet 32 is Even if it has a portion such as the boss portion 34 formed by drawing, the raised portion of the resin that can come into contact with the rear surface 22 of the rack bar 20 at a position different from the predetermined support position is slid on the rack guide sheet 32. It is not formed on the moving surface 33. Therefore, since the rack bar 20 can be stably supported at the original support position, the steering wheel system can exhibit the desired steering performance.

  Thus, since it is not necessary to avoid contact between the resin bulge and the back surface 22 of the rack bar 20, for example, two arcuate surfaces 33A and 33B that support the back surface 22 of the rack bar 20 in a linear or belt-like region are provided. When included in the sliding surface 33 of the rack guide sheet 32, the offset amount r of the curvature centers OA and OB of the two arcuate surfaces 33A and 33B from the axis O of the rack bar 20 can be further reduced. Thereby, since the swinging of the rack bar 20 can be suppressed by the two arcuate surfaces 33A and 33B, the generation of abnormal noise can be prevented and the steering performance of the steering wheel can be further improved.

  In addition, this invention is not limited to said embodiment, Many deformation | transformation are possible within the range of the summary.

  For example, in the present embodiment, the rack bar support layer 322 that supports the back surface 22 of the rack bar 20 is porous so that the porous metal layer 324 and the metal 3241 of the porous metal layer 324 are dispersedly exposed from the surface. The resin layer 323 covering the metal layer 324 is included, but this is not necessarily required. For example, instead of the porous metal layer 324, a metal having a plurality of voids that can be filled with resin from one surface side, such as an expanded metal formed in a net shape, a punching metal in which a plurality of through holes are formed, etc. A sheet material may be used.

  Further, in the present embodiment, the rack guide sheet 32 having the sliding surface 33 in which both the resin 3231 and the metal 3241 are exposed at an appropriate ratio is fixed to the one end portion 31B side of the metal base portion 31. However, without using such a rack guide sheet 32, the curved surface of the groove portion 37 is exposed by exposing both the resin and metal at an appropriate ratio on the curved inner surface of the groove portion 37 of the base portion 31. The inner surface of the shape may function as a sliding surface.

  In order to obtain such a structure, for example, the base portion 31 is made of a porous sintered metal, and the curved surface of the groove portion 37 of the base portion 31 is so formed that the surface layer of at least the groove portion 37 of the base portion 31 is impregnated with resin. Resin is lined on the inner surface, and the surface layer of the resin film formed thereby may be removed by machining or the like until the metal of the base portion 31 is exposed at an appropriate ratio. As a result, a rack bar support layer having the same structure as the rack bar support layer 322 of the rack guide sheet 32 (a porous sintered metal forming the inner surface of the groove 37 of the base portion 31) is formed on the surface layer of the groove portion 37 of the base portion 31. And a layer including a resin that fills the pores of the porous sintered metal and covers a part of the inner surface (the surface of the porous sintered metal) of the groove portion 37 of the base portion 31 is formed.

  Alternatively, an unevenness is formed on the entire inner surface of the groove portion 37 of the base portion 31, and a resin sheet having an inverted shape of the unevenness is formed so that the convex portion on the resin sheet side enters the concave portion on the base portion 31 side. Until the metal of the base portion 31 is exposed from the resin at an appropriate ratio until the metal of the base portion 31 is exposed from the resin at a suitable ratio (resin other than the concave portion on the base portion 31 side) from the resin sheet. It may be removed by processing or the like.

  Further, in the present embodiment, the rack guide sheet 32 has the boss portion 34 that is molded by press molding. However, the rack guide sheet 32 is molded by press molding such as a grease groove that is filled with grease or the like. It may have other parts. Thus, even when the rack guide sheet 32 has a portion other than the boss portion 34, the resin guide does not form on the sliding surface 33 of the rack guide sheet 32 due to the press molding process. The 32 sliding surfaces 33 can be accurately formed.

  The steering device may be equipped with a power steering mechanism that assists the movement of the pinion gear 11 or the rack bar 20 with a motor.

  In the above embodiment, an example of application to a vehicle steering device is given. However, the present invention is not limited to a vehicle steering device, and a rack and pinion type gear mechanism such as a focusing mechanism of an optical device, for example, is used. It can be widely applied to the equipment that is used.

1: rack and pinion gear mechanism, 10: pinion shaft, 11: pinion gear, 12: outer peripheral surface of pinion shaft, 13: end of pinion shaft, 20: rack bar, 21: rack gear, 22: rack bar Back side, 30: Rack guide, 31: Base part, 32: Rack guide sheet, 33: Sliding surface 33A, 33B: Arc surface, 34: Boss part, 35: Spring guide, 36: Through hole for fixing base part to sheet 37: groove portion of the base portion, 38A: bottom surface of the base portion, 38B: upper surface of the base portion, 39: outer peripheral surface of the base portion, 50: bearing, 40: coil spring, 60: cap, 61: inner surface of the cap, 62: Screw part of cap, 70: Housing, 71: Rack case part, 72: Cylinder case 73, pinion gear housing part, 74, 75: opening, 76: open end part of cylinder case part, 77: screw part of cylinder case part, 78: inner wall surface of cylinder case part, 80: elastic member, 341: Boss peripheral area, 351: bottom surface of spring guide, 391: groove on outer peripheral surface of base portion, 321: metal plate, 322: rack bar support layer, 323: resin layer, 324: porous sintered metal layer, 325 : Front surface of rack bar support layer, 326: Back surface of rack guide sheet, 3231: Resin, 3241: Metal

Claims (8)

A rack bar formed with a rack gear that meshes with the pinion gear is slidably supported from the opposite side of the rack gear, and the rack bar that moves according to the rotation of the pinion gear is guided in the axial direction of the rack bar. A rack guide,
A guide bar support layer including a metal having a plurality of voids and a resin filled in the voids of the metal,
The guide bar support layer has a surface exposed by mixing the metal and the resin as a sliding surface that supports the rack bar so as to be slidable in the axial direction of the rack bar. Rack guide. The rack guide according to claim 1,
The rack guide according to claim 1, wherein the guide bar support layer includes a porous metal including the plurality of gaps as the metal. The rack guide according to claim 2, wherein
A rack guide sheet having a metal plate and the guide bar support layer formed on one surface of the metal plate and having the sliding surface on the opposite side of the metal plate,
The guide bar support layer is
A porous sintered metal layer formed on one surface of the metal plate by the porous metal;
The resin filled in the plurality of voids of the porous sintered metal is formed so that the sliding surface is formed from the resin and the porous metal exposed from the resin. A rack guide that covers a part of the surface of the layer. The rack guide according to claim 1,
The rack guide, wherein the guide bar support layer includes, as the metal, an expanded metal that forms the plurality of gaps or a punching metal in which the plurality of gaps are formed. The rack guide according to any one of claims 1 to 4,
The rack guide according to claim 1, wherein the sliding surface includes two arcuate surfaces that support the rack bar in a region along an axis of the rack bar. The rack guide according to claim 5, wherein
The outer peripheral surface of the rack bar includes an arc surface that slides with the sliding surface,
The rack guide, wherein an offset amount of the center of curvature of the two arc surfaces from the axis of the rack bar supported by the two arc surfaces is 1 mm or less. A gear mechanism that changes the traveling direction of the moving body according to the rotation of the steering wheel,
A pinion gear that rotates according to the rotation of the steering wheel;
A rack bar that meshes with the pinion gear, and a rack bar that reciprocates according to the rotation of the pinion gear and changes the direction of the wheels of the moving body by meshing the pinion gear and the rack gear;
The rack guide according to any one of claims 1 to 6, wherein the rack bar is slidably supported on the sliding surface of the rack guide sheet in the axial direction of the rack bar.
An elastic body that urges the rack in a direction in which the rack gear is pressed against the pinion gear. A rack guide manufacturing method for manufacturing a rack guide having a sliding surface for guiding a rack bar formed with a rack gear meshing with a pinion gear in the axial direction of the rack bar,
A metal member having a plurality of recesses formed on a surface facing the rack bar and a resin member having a plurality of projections corresponding to the plurality of recesses correspond to each of the plurality of recesses. The resin and the resin are formed by removing the resin other than the protrusion from the resin member so that the metal forming the metal member is exposed from the resin forming the resin member in combination so that the protrusion is fitted. A method of manufacturing a rack guide, comprising forming the sliding surface in which metal is dispersed.

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