JP2008296626A - Bush bearing and rack pinion type hydraulic power steering device for automobile using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bush bearing in which a rack shaft can be supported for a long period with appropriate interference to provide good moving characteristics in an axial direction with low sliding friction resistance with respect to the rack shaft without generating a clearance, and generation of abnormal noise caused by vibration is prevented, and machining man-hours and assembly man-hours are decreased to reduce cost, and to provide a rack pinion type power hydraulic steering device for an automobile using the same. <P>SOLUTION: The rack pinion type power hydraulic steering device 1 for an automobile comprises: an outer cylinder 4 in which the rack shaft 3 is inserted to the inside 2 thereof; the bush bearing 13 fitted to an inner circumferential surface 9 of an outer cylinder; a small-diameter seal ring 15 received by a bush groove 14; a large-diameter seal ring 17 received by an inner cylinder groove 16; and an inside seal ring 23 brought into slide-contact with an outer circumferential surface 18 of the rack shaft 3 in an A direction, and is brought into contact with a large diameter inner circumferential surface 22 of an inner cylinder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bush bearing, and more particularly to a bush bearing suitable for use in movably supporting a rack shaft in a rack and pinion type hydraulic power steering apparatus of an automobile.

Japanese Utility Model Publication 1-17-1775 Japanese Utility Model Publication No. 5-49566 Utility Model Registration No. 2576192 JP 11-115773 A JP 2001-10511 A

  As described in Patent Documents 1 to 5, in a rack and pinion type steering device, in particular, a rack and pinion type hydraulic power steering device, a rack shaft having rack teeth that mesh with the teeth of the pinion houses oil. It is movably supported at one end of the outer cylinder (housing) via a bush bearing. As a bush bearing, an inner cylinder made of metal or resin that is fitted to the inner peripheral surface of one end of the outer cylinder, and an outer peripheral surface of the rack shaft that is mounted on the inner peripheral surface of the inner cylinder and is the inner peripheral surface There have been proposed various types including a synthetic resin bush that is slidably in contact with the bush.

  In such a bushing bearing, if there is a gap between the inner peripheral surface of the bush and the outer peripheral surface of the rack shaft, a collision sound (abnormal noise) between the bush and the rack shaft is generated when the vehicle is running, and the passengers feel uncomfortable. If the rack shaft is tightly tightened with a bush with a large margin so that there is no gap, the sliding frictional resistance in the axial direction will increase and the rack shaft cannot be supported with good movement characteristics. On the other hand, if the rack shaft to be supported is tightened loosely with a small tightening margin, good movement characteristics in the axial direction with low sliding friction resistance can be expected, but the rack shaft has a large misalignment and A gap or the like is likely to be generated between the rack shaft and the radial support is lowered, which may cause a collision sound.

  In addition, when the bush is interposed between the inner peripheral surface of the inner cylinder and the outer peripheral surface of the rack shaft, the synthetic resin bush is tightened to the outer peripheral surface of the rack shaft with an appropriate tightening margin through the inner cylinder. However, when creep deformation, sag, etc. occur in the bush over a long period of use, it becomes difficult to tighten the outer periphery of the rack shaft with the initial allowance depending on the bush, and there is a problem between the bush and the outer peripheral surface of the rack shaft. There is a possibility that a gap is easily formed in the rack, and abnormal noise may be generated due to the collision of the rack shaft with the bush due to vibration.

  On the other hand, the rack shaft is normally movably supported by the bush bearings at two portions, the side adjacent to the pinion and the side away from the pinion. In particular, the rack shaft is separated from the pinion in the rack and pinion type hydraulic power steering device. In addition to the movable support of the rack shaft by the bush bearing, the oil liquid from the inside of the outer cylinder to the outside is provided at one end of the opening side of the outer cylinder in which the oil liquid is accommodated. The leakage prevention is performed with a seal ring. However, if such a leakage prevention seal ring and bushing bearing must be individually installed inside the outer cylinder, it becomes a complicated operation, which increases the price. There is a risk of being invited.

  The present invention has been made in view of the above-described points, and an object of the present invention is to obtain a good axial movement characteristic with a low sliding frictional resistance with respect to the rack shaft without causing a gap. Bush bearings that can support the rack shaft over a long period of time with an appropriate tightening allowance, eliminate the generation of abnormal noise due to vibration, and reduce the number of processing and assembly steps, thereby reducing the price. Another object of the present invention is to provide an automotive rack and pinion type hydraulic power steering apparatus using the same.

  The bush bearing of the present invention is fitted to the inner peripheral surface of the outer cylinder with a small diameter at one end of the outer cylinder through which the rack shaft is inserted, and is also penetrated through one end of the rack shaft inserted into the outer cylinder. A bush made of synthetic resin that can be reduced in diameter, and one end of a rack shaft inserted through the inside of the outer cylinder are penetrated and connected to one end of the bush in the axial direction, and the inner diameter of the outer cylinder at one end of the outer cylinder is increased. An inner cylinder fitted to the peripheral surface, and a connecting means for connecting the bush and the inner cylinder to each other, the bush extending from one end surface of the axial bush to the other end surface of the axial bush; A cylindrical bush inner peripheral surface that is slidably in contact with the outer peripheral surface of the rack shaft, a cylindrical bush small outer peripheral surface facing the outer peripheral small diameter inner peripheral surface, and an outer cylindrical small inner peripheral surface that is elastically pressed Bush small diameter outer surface to accept the outer small diameter seal ring in contact An annular bush groove formed and a cylindrical bush large-diameter outer surface connected to the bush small-diameter outer peripheral surface in the axial direction via an annular bushing inclined outer peripheral surface and facing the outer cylindrical large-diameter inner peripheral surface A plurality of bush recesses extending in the axial direction from the other end surface of the bush toward the one end surface of the bush and arranged in a direction around the axis, and the inner cylinder is disposed on the other end surface of the bush. An axial end of the inner cylinder that comes into contact, an outer peripheral surface of the inner cylinder that is fitted to the inner peripheral surface of the outer diameter of the outer cylinder, and an outer large-diameter seal ring that elastically presses and contacts the inner peripheral surface of the outer cylinder. An annular inner cylindrical groove formed on the outer peripheral surface of the inner cylinder to receive, a cylindrical inner cylinder inner peripheral surface that slidably contacts the outer peripheral surface of the rack shaft, one end surface of the inner cylinder, and an inner cylinder inner periphery The rack shaft is arranged between the surfaces and has a larger diameter than the inner peripheral surface of the inner cylinder. The outer peripheral surface of the inner seal ring slidably contacts the inner circumferential surface on the outer peripheral surface is provided with an inner cylindrical large diameter inner peripheral surface in contact.

  According to the bush bearing of the present invention, the bush and the inner cylinder are connected in the axial direction, and the outer cylinder inner peripheral surface having the outer cylinder small-diameter inner peripheral surface and the outer cylinder large-diameter inner peripheral surface at one end portion of the outer cylinder is provided. In addition, since the bush has a slit and a plurality of bush recesses, creep deformation of the bush, sag, etc. can be preferably avoided, and the rack shaft can be extended for a long time with an initial tightening allowance. The outer peripheral surface can be tightened by a bush, and thus the rack shaft can be extended for a long time so that good movement characteristics in the axial direction can be obtained with low sliding friction resistance against the rack shaft without generating a gap. The inner cylinder has an inner cylinder large-diameter inner circumferential surface arranged between one end surface of the inner cylinder and the inner circumferential surface of the cylinder. For this reason, the inner diameter of the inner cylinder In order to be able to mount the inner sealing ring, may work to lower prices and reduces the number of processing steps and assembling steps.

  The inner cylinder may be formed of a metal material such as aluminum or iron, or alternatively may be formed of a synthetic resin material having a predetermined rigidity, and the synthetic resin as a material for forming the bush has excellent wear resistance. A material having low friction characteristics and having a predetermined flexibility and rigidity and low thermal expansion and contraction is preferable. Specifically, at least one of a polyacetal resin, a polyamide resin, a polyolefin resin, and a fluorine resin is used. Examples thereof include synthetic resins.

  In a preferred example, the inner cylinder has a plurality of inner cylinder recesses extending in the axial direction from one end opened at one end surface of the inner cylinder and arranged at angular intervals in the direction around the axis. In a preferred example of the above, the inner cylinder has another cylindrical inner diameter larger inner circumferential surface having a larger diameter than the inner circumferential surface of the inner cylinder, and one axial end of the other inner cylinder larger inner diameter surface. And a plurality of other inner cylinder intermediate end faces that are connected to each other at the outer peripheral edge, and extending in the axial direction from one end opened at the inner cylinder intermediate end face and arranged at equiangular intervals in the direction around the axis. If the inner cylinder has these inner cylinder recesses, when the bush bearing is fitted to the inner cylinder inner peripheral surface of one end of the outer cylinder, the inner cylinder inner circumference Even if the dimensional accuracy of the surface is somewhat poor, this can be absorbed by the inner cylinder recess, and therefore the bias is excessively biased by the inner peripheral surface of the inner cylinder. Or the outer peripheral surface of the click-axis is pressed, that the required minimum clearance between the inner cylinder peripheral surface and the rack shaft outer peripheral surface of the (bearing clearance) is or cause can be prevented.

  The slit may extend in parallel to the axial direction, or alternatively, may be inclined and extended with respect to the axial direction. It may be mixed with slanted and elongated ones.

  A rack and pinion type hydraulic power steering device for an automobile according to the present invention is slidable between an outer cylinder through which a rack shaft is inserted into an oil-filled interior and one end portion of the rack shaft inserted into the outer cylinder. In order to support, the bushing bearing of any one of the above-described aspects is fitted to the outer peripheral small diameter inner peripheral surface and the outer peripheral large diameter inner peripheral surface, the small diameter seal ring received in the bush groove, and received in the inner cylindrical groove A large-diameter seal ring, and an inner seal ring that is slidably in contact with the outer peripheral surface of the rack shaft on the inner peripheral surface and whose outer peripheral surface is in contact with the inner peripheral surface of the inner cylinder.

  As the small-diameter seal ring and the large-diameter seal ring, a generally used O-ring can be preferably used, and the inner seal ring may have an oval shape that is circular, elliptical, rectangular or flat in cross section. Alternatively, other shapes such as an X-shaped cross-section, a U-shaped cross-section or a trapezoidal cross-section may be used. Preferably, the shape is made of natural rubber or synthetic rubber, but has other elasticity. It may be made of a thermoplastic synthetic resin, for example, a polyester elastomer.

  According to the present invention, the rack shaft is supported over a long period of time with a moderate tightening margin so that a good moving characteristic in the axial direction can be obtained with a low sliding friction resistance with respect to the rack shaft without generating a gap. Provided is a bush bearing that can eliminate abnormal noise due to vibration and that can reduce the processing man-hours and assembly man-hours and can reduce the price, and a rack and pinion type hydraulic power steering device for an automobile using the same. be able to.

  The invention will now be described in more detail with reference to the preferred embodiment examples shown in the drawings. The present invention is not limited to these examples.

  1 to 9, a rack and pinion type hydraulic power steering device 1 for an automobile according to the present embodiment includes an outer cylinder (housing) 4 through which a rack shaft 3 is inserted into an interior 2 filled with oil, and an outer cylinder 4 In order to slidably support one end portion 5 of the rack shaft 3 inserted through the inside 2 in the A direction which is the axial direction, the cylindrical outer tube small-diameter inner peripheral surface 7 and the outer tube of the one end portion 6 of the outer tube 4 A small-diameter received in a bush bearing 13 having a bush 11 and an inner cylinder 12 and an annular bush groove 14 of the bush 11 while being fitted to an outer cylinder inner peripheral surface 9 having a large-diameter inner peripheral surface 8. The seal ring 15, the large-diameter seal ring 17 received in the annular inner cylindrical groove 16 of the inner cylinder 12, and the cylindrical inner peripheral surface 19 are slid in the A direction on the cylindrical outer peripheral surface 18 of the rack shaft 3. The cylindrical outer cylinder 21 of the inner cylinder 12 is in contact with the movable body and the cylindrical outer peripheral surface 21 is large An inner seal ring 23 that contacts the inner peripheral surface 22 and a bellows-like shape for preventing intrusion of muddy water and dust, in which one end portion 26 is fixed to the cylindrical inner cylinder outer peripheral surface 24 of the inner cylinder 12 by a tightening ring 25. An elastic cover 27 is provided.

  A meshing mechanism with a pinion rotated by rotation of a steering wheel (steering wheel) on the other end side of the rack shaft 3, a mechanism for supplying oil to the inside 2 of the outer cylinder 4, and one end portion 5 of the rack shaft 3 Since a connecting mechanism with a tie rod or the like for transmitting the movement of the rack shaft 3 in the A direction on the side to the axle is well known, detailed description thereof will be omitted.

  One end portion 6 of the outer cylinder 4 is formed with a cylindrical outer cylinder outer peripheral surface 31, an outer cylinder small-diameter inner peripheral surface 7 defining the inside 2, and an annular fitting recess 32 and an outer cylinder small-diameter An outer cylinder large-diameter inner peripheral surface 8 larger in diameter than the inner peripheral surface 7, an outer cylinder small-diameter inner peripheral surface 7 at one end in the A direction, and an outer cylinder large-diameter inner peripheral surface 8 at the other end in the A direction. The outer cone inclined inner peripheral surface 33 having a truncated conical shape connected to each other, and the outer cylinder outer peripheral surface 31 at the outer peripheral end in the radial direction and the outer cylinder large diameter inner peripheral surface 8 at the inner peripheral end in the radial direction are orthogonal to each other. And an annular outer cylinder end surface 34 connected to each other.

  The bush bearing 13 is fitted to the inner peripheral surface 7 of the outer cylinder with a small diameter at one end 6 of the outer cylinder 4 through which the rack shaft 3 is inserted, and the bush shaft 13 is inserted into the inner 2 of the outer cylinder 4. A bush 11 made of a synthetic resin that can be freely reduced in diameter through which the one end 5 passes, and one end 5 of the rack shaft 3 inserted through the inside 2 of the outer cylinder 4 are penetrated and connected to one end of the bush 11 in the A direction. The inner cylinder 12 fitted to the outer cylinder large-diameter inner peripheral surface 8 of the one end portion 6 of the outer cylinder 4 and the connecting means 35 for connecting the bush 11 and the inner cylinder 12 to each other are provided.

  The bush 11 integrally having an inner cylindrical portion 36, an outer cylindrical portion 37, and an annular portion 38 in which the inner cylindrical portion 36 and the outer cylindrical portion 37 are connected to each other at one end in the A direction, A slit 43 extending from one end face 41 of the annular bushing in the A direction to the other end face 42 of the annular bushing in the A direction, and an inner side contacting the outer peripheral surface 18 of the rack shaft 3 slidably in the A direction with a tightening margin. The cylindrical bush inner peripheral surface 44 of the cylindrical portion 36, the cylindrical bush small diameter outer peripheral surface 45 of the outer cylindrical portion 37 facing the outer cylindrical small diameter inner peripheral surface 7 of the outer cylinder 4, and the outer cylinder small diameter inner periphery An annular bush groove 14 formed in the bush small-diameter outer peripheral surface 45 so as to receive the outer small-diameter seal ring 15 that elastically presses and contacts the surface 7 on the outer peripheral surface, and an annular shape on the bush small-diameter outer peripheral surface 45. There is a truncated cone-shaped bush tilt A cylindrical bush large-diameter outer peripheral surface 47 that is connected in the A direction via the outer peripheral surface 46 and faces the outer cylindrical large-diameter inner peripheral surface 8, and the bush other end surface 42 toward the bush one end surface 41 respectively. A plurality of bottomed bush recesses 48 extending in the direction and arranged in the R direction, which is a direction around the axis.

  The slit 43 opens at one end surface 41 of the bush and extends parallel to the A direction from the one end surface 41 of the bush, and parallel extends from the other end surface 42 of the bush and parallel to the A direction from the other end surface 42 of the bush. The slit 52 has, on the one hand, a parallel slit 51 and, on the other hand, an inclined slit 53 which is communicated with the parallel slit 52 and extends with an inclination with respect to the A direction. The direction of the diameter is easily reduced.

  The bush inner peripheral surface 44 defines a through hole 54 through which one end portion 5 of the rack shaft 3 passes, and the bush inclined outer peripheral surface 46 is in contact with the outer cylinder inclined inner peripheral surface 33, Further insertion of the bush 11 into the one end 6 of the outer cylinder 4 is prevented.

  The inner cylinder 12 integrally including an inner cylindrical portion 56, an outer cylindrical portion 57, and an annular portion 58 that connects the inner cylindrical portion 56 and the outer cylindrical portion 57 at an intermediate portion in the A direction is the A cylindrical inner cylinder large-diameter outer peripheral surface 24 located outside the one end 6, an A-shaped annular inner cylinder one end surface 61 contacting the bushing other end surface 42, and an outer cylinder large-diameter inner peripheral surface 8. Formed on the outer peripheral surface 62 of the inner cylinder so as to receive the outer peripheral surface 62 of the cylindrical inner cylinder to be worn and the outer large-diameter seal ring 17 that elastically presses and contacts the outer peripheral large-diameter inner peripheral surface 8 with the outer peripheral surface. An annular inner cylindrical groove 16 formed in the cylindrical shaft, a cylindrical inner cylinder inner peripheral surface 63 that is slidably in contact with the outer peripheral surface 18 of the rack shaft 3 in the A direction with a bearing gap, and an inner cylinder one end surface 61 in the A direction. And the inner diameter of the inner cylinder 63 is larger than the diameter of the inner circumference 63 of the inner cylinder, and the rack shaft 3 An inner cylinder large-diameter inner peripheral surface 64 in contact with the outer peripheral surface 21 of the inner seal ring 23 that is slidably in contact with the outer peripheral surface 18 in the A direction on the inner peripheral surface 19, and an inner cylinder large-diameter inner peripheral surface 64 and an inner cylinder The other cylindrical inner diameter inner circumferential surface 65 having a larger diameter than the inner circumferential surface 63 and a circle connected to one end in the A direction of the inner cylindrical larger diameter inner circumferential surface 65 at an outer peripheral edge. The inner cylinder intermediate end face 66 is larger than the diameter of the annular inner cylinder intermediate end face 66 and the inner cylinder inner peripheral face 63 and smaller than the diameter of the inner cylinder larger inner peripheral face 64 and at one end in the A direction. An inner cylinder intermediate inner peripheral surface 67 connected perpendicularly to the inner peripheral edge of 66, and a bottomed structure extending in the A direction from one end opened at the inner cylinder one end surface 61 and arranged at equal angular intervals in the R direction. A plurality of inner cylinder recesses 68 and one end opened at the inner cylinder intermediate end surface 66 extend in the A direction and in the R direction, etc. A plurality of bottomed inner cylinder recesses 69 arranged at intervals, and the other end surface of the annular inner cylinder connected perpendicularly at the inner periphery to the other end in the A direction of the inner diameter inner surface 65 of the inner cylinder 71, an annular inner cylinder outer stepped end surface 72 which is connected to the inner cylinder outer peripheral surface 62 at the inner peripheral edge and orthogonally connected to the inner cylindrical outer peripheral surface 24 at the outer peripheral edge and in contact with the outer cylinder end surface 34. And an inner cylinder inner stepped end surface 73 connected to the inner cylinder inner peripheral surface 63 at the inner peripheral edge and orthogonally connected to the inner cylinder large diameter inner peripheral surface 64 at the outer peripheral edge.

  The inner cylinder inner peripheral surface 63, the inner cylinder large diameter inner peripheral surface 64, the inner cylinder large diameter inner peripheral surface 65, and the inner cylinder intermediate inner peripheral surface 67 define a through hole 74 through which one end portion 5 of the rack shaft 3 passes. ing.

  The inner cylinder outer peripheral surface 62 is formed with a cylindrical fitting protrusion 75 that is fitted in the fitting recess 32 and protrudes integrally from the inner cylinder outer peripheral surface 62 in the radial direction. By fitting the mating protrusion 75 into the fitting recess 32, the cylindrical inner cylinder outer peripheral surface 62 is fitted to the outer cylinder large diameter inner peripheral surface 8 of the outer cylinder 4, and thus, The inner cylinder 12 is positioned in the A direction with respect to the one end 6 of the outer cylinder 4 by fitting the fitting protrusion 75 into the fitting recess 32.

  An annular groove 77 and an annular groove 78 connected to the groove 77 in the A direction and deeper than the groove 77 are formed in the inner cylinder large-diameter outer peripheral surface 24 of the inner cylinder 12.

  One end portion 26 of the extendable cover 27 is fitted in the grooves 77 and 78, and the one end portion 26 is fixed to the inner cylinder large-diameter outer peripheral surface 24 of the inner cylinder 12 by a fastening ring 25.

  The connecting means 35 is formed integrally with the bush 11 at the bush other end surface 42 in an axially symmetrical manner and has a pair of flange members 81 projecting from the bush other end surface 42 in the A direction, and a tip flange 82 of the flange member 81. An annular groove 83 formed on the outer peripheral surface 62 of the inner cylinder 12 of the inner cylinder 12 and a main body 84 of the flange member 81 are inserted, and a cut formed symmetrically on the outer peripheral surface 62 of the inner cylinder. And a notch 85.

  The bush 11 and the inner cylinder 12 are connected to each other by engagement with the bush 11 in the groove 83 of the distal end flange portion 82 and engagement with the bush 11 in the notch 85 of the main body portion 84 and in the R direction. It is designed not to rotate relative to.

  While the inner peripheral surface 19 contacts the outer peripheral surface 18 of the rack shaft 3 slidably in the A direction, the inner seal ring 23 that contacts the inner cylinder large diameter inner peripheral surface 64 at the outer peripheral surface 21 has one side in the A direction. The annular end surface 91 is in contact with the bush other end surface 42 and the other annular end surface 92 in the A direction is in contact with the inner cylinder inner stepped end surface 73, and is pressed between the bush other end surface 42 and the inner cylinder inner stepped end surface 73. Yes.

  In the rack and pinion type hydraulic power steering apparatus 1 having the bush bearing 13 described above, the bush 11 and the inner cylinder 12 are connected in the A direction and fitted to the inner cylinder inner peripheral surface 9 of the one end portion 6 of the outer cylinder 4. In addition, since the bush 11 includes the slit 43 and the plurality of bush recesses 48, it is possible to preferably avoid creep deformation, sag, etc. of the bush 11, and to extend the rack shaft over a long period with an initial tightening allowance. 3 can be fastened by the bush 11, so that a good moving characteristic in the A direction can be obtained with a low sliding friction resistance with respect to the rack shaft 3 without generating a gap. The rack shaft 3 can be supported over a long period of time, and noise generation due to vibration can be eliminated. In addition, the inner cylinder 12 has an inner cylinder end surface 61 and a cylindrical inner end in the A direction. Since the inner cylinder large-diameter inner peripheral surface 64 arranged between the inner peripheral surfaces 63 is provided, the inner seal ring 23 can be attached to the inner cylinder large-diameter inner peripheral surface 64 in advance. The number of man-hours and assembly man-hours can be reduced and the price can be reduced.

It is sectional explanatory drawing of an example of preferable embodiment of this invention. It is an expanded sectional explanatory view of the bush and seal ring of the example shown in FIG. FIG. 3 is a left side view of the bush shown in FIG. 2. It is a right view of the bush shown in FIG. It is a front view of the bush shown in FIG. It is an expanded sectional explanatory view of the inner cylinder and seal ring of the example shown in FIG. It is a left view of the inner cylinder shown in FIG. It is a right view of the inner cylinder shown in FIG. It is a front view of the inner cylinder shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rack and pinion type hydraulic power steering device 2 Inside 3 Rack shaft 4 Outer cylinder 5, 6 One end part 7 Outer cylinder small diameter inner peripheral surface 8 Outer cylinder large diameter inner peripheral surface 9 Outer cylinder inner peripheral surface 11 Bush 12 Inner cylinder 13 Bush bearing 14 Bush groove 15 Small diameter seal ring 16 Inner cylinder groove 17 Large diameter seal ring 18 Outer peripheral surface 19 Inner peripheral surface 21 Outer peripheral surface 22 Inner cylinder large diameter inner peripheral surface 23 Inner seal ring 35 Connecting means 41 Bush one end surface 42 Bush other end surface 43 Slit 44 Bush inner peripheral surface 45 Bush small diameter outer peripheral surface 46 Bush inclined outer peripheral surface 47 Bush large outer peripheral surface 48 Bush recess 61 Inner cylinder one end surface 62 Inner cylinder outer peripheral surface 63 Inner cylinder inner peripheral surface 64 Inner cylinder larger diameter inner peripheral surface 65 Inner cylinder large-diameter inner peripheral surface 66 Inner cylinder intermediate end surface 67 Inner cylinder intermediate inner peripheral surface 68, 69 Inner cylinder recess 71 Inner cylinder other end surface 72 Inner cylinder outer stepped end surface 3 inner cylinder inner stepped end face

Claims (4)

  Made of a synthetic resin that can be reduced in diameter and is fitted on the inner peripheral surface of the small outer diameter of the outer cylinder of one end of the outer cylinder through which the rack shaft is inserted, and through which one end of the rack shaft is inserted through the outer cylinder. And one end of the rack shaft inserted through the inside of the outer cylinder are penetrated and connected to one end of the bush in the axial direction and are fitted to the outer cylinder large-diameter inner peripheral surface of one end of the outer cylinder. An inner cylinder, and a bush and a coupling means for coupling the inner cylinder to each other. The bush is slid onto the outer peripheral surface of the rack shaft and a slit extending from one axial end of the bush to the other axial end of the bush. Cylindrical bush inner peripheral surface that contacts freely, cylindrical bush small-diameter outer peripheral surface facing outer cylindrical small-diameter inner peripheral surface, and outer small-diameter seal ring that elastically presses and contacts outer cylindrical small-diameter inner peripheral surface An annular bush formed on the outer peripheral surface of the bush A cylindrical bush large-diameter outer surface that is axially connected to the small-diameter outer surface of the bush via an annular inclined outer peripheral surface of the bush and faces the large-diameter inner peripheral surface of the outer cylinder, and the other end surface of the bush A plurality of bush recesses extending in the axial direction toward the one end surface of the bush and arranged in the direction around the shaft center are provided, and the inner cylinder is in the axial direction in contact with the other end surface of the bush. One end surface of the cylinder, an outer peripheral surface of the inner cylinder that is fitted on the inner peripheral surface of the outer cylinder, and an inner cylinder that receives the outer large-diameter seal ring that is elastically pressed into contact with the outer diameter of the outer cylinder. An annular inner cylinder groove formed on the outer circumferential surface, a cylindrical inner cylinder inner circumferential surface that slidably contacts the outer circumferential surface of the rack shaft, and an inner cylinder one end surface and an inner cylinder inner circumferential surface. In addition, it has a diameter larger than the inner peripheral surface of the inner cylinder, and slides on the outer peripheral surface of the rack shaft on the inner peripheral surface. Bush bearing outer circumferential surface of the inner sealing ring is provided with an inner cylindrical large-diameter inner peripheral surface in contact in contact with.   2. The bush according to claim 1, wherein the inner cylinder has a plurality of inner cylinder recesses extending in an axial direction from one end opened at one end surface of the inner cylinder and arranged at angular intervals in a direction around the axis. bearing.   The inner cylinder is connected at the outer peripheral edge to the other inner cylinder large-diameter inner peripheral surface having a larger diameter than the inner peripheral surface of the inner cylinder and one axial end of the other inner-large-diameter inner peripheral surface. And a plurality of other inner cylinder recesses extending in the axial direction from one end opened at the inner cylinder intermediate end face and arranged at equal angular intervals in the direction around the axis. The bushing bearing according to claim 1 or 2 having.   An outer cylinder through which the rack shaft is inserted into the oil-filled interior, and an outer cylinder small-diameter inner peripheral surface and an outer cylinder large in order to slidably support one end of the rack shaft inserted into the outer cylinder. The bush bearing according to any one of claims 1 to 3, fitted on a radially inner peripheral surface, a small-diameter seal ring received in the bush groove, a large-diameter seal ring received in the inner cylindrical groove, A rack and pinion type hydraulic power steering apparatus for an automobile having an inner seal ring that slidably contacts an outer peripheral surface of a rack shaft on an inner peripheral surface and an outer peripheral surface contacts an inner peripheral surface of a large-diameter inner cylinder.

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