JP2018179024A - Sliding bearing - Google Patents

Abstract

Kind Code: A1 A sliding bearing is provided in which the durability of an elastic body can be improved to extend the life of the bearing. A rack bushing (1) is housed in a cylindrical housing, and supports a load applied to the rack shaft while allowing movement of the rack shaft (5) in the direction of the axis O, into which the rack shaft is inserted. A cylindrical bushing body 2, which is mounted on the bushing body 2, protrudes outward from the outer peripheral surface of the bushing body 2, and contacts the inner peripheral surface of the housing when the rack bushing is accommodated in the housing. and an elastic member 3 for urging radially inwardly. The bush body 2 has a slit formed along the direction of the axis O from one end face to the other end face. The elastic member 3 has a protruding portion that protrudes outward while being inclined with respect to the radial direction of the bush body 2 and contacts the inner peripheral surface of the housing. [Selection drawing] Fig. 2

Description

  The present invention relates to a slide bearing for supporting a load applied to a shaft member while allowing axial movement of the shaft member, and more particularly to a slide bearing suitable for a rack bush used in a steering mechanism of a vehicle.

  In Patent Document 1, as a slide bearing suitable for a rack bush used in a steering mechanism of a vehicle, it is housed in a cylindrical housing with axial movement restricted, and axial movement of the rack shaft is permitted. However, a sliding bearing is described which supports the load applied to the rack shaft.

  The slide bearing includes a cylindrical bearing main body into which the rack shaft is inserted, and an elastic ring mounted on the bearing main body, made of an elastic body such as rubber or elastomer, and biasing the bearing main body radially inward. Have. The bearing main body is made of synthetic resin, and is formed along the axial direction from the other end face to one end face, with the first slit formed along the axial direction from one end face to the other end face And a mounting groove formed on the outer peripheral surface of the bearing body and into which the elastic ring is mounted.

  According to this slide bearing, the diameter of the bearing body is reduced by the elastic ring, and the rack shaft inserted into the bearing body is tightened. Therefore, the clearance between the inner peripheral surface of the bearing body and the outer peripheral surface of the rack shaft is made zero. While being able to prevent the generation of unpleasant noise due to a collision between the inner peripheral surface of the bearing body and the outer peripheral surface of the rack shaft, it is possible to prevent the fluctuation of the friction torque due to the outer diameter dimension error of the rack shaft.

JP, 2008-151289, A

  By the way, in the slide bearing described in Patent Document 1, the elastic ring attached to the bearing body is compressed and deformed while being sandwiched between the rack shaft inserted in the bearing body and the housing in which the slide bearing is accommodated. used. For this reason, deterioration of elastic bodies, such as rubber and an elastomer used for an elastic ring, advances, and there is a problem that the life of a slide bearing becomes short.

  This invention is made in view of the said situation, The objective is to provide the slide bearing which can achieve durability improvement of an elastic body and can achieve lifetime improvement.

  In order to solve the above problems, in the slide bearing according to the present invention, an elastic member protruding outward from the outer peripheral surface of the bearing main body is attached to a radially expandable cylindrical bearing main body into which the shaft member is inserted. doing. Then, the elastic member is provided with a projecting portion that abuts against the inner peripheral surface of the housing when the elastic member protrudes outward while inclining with respect to the radial direction of the bearing main body and is accommodated in, for example, a cylindrical housing. .

For example, the sliding bearing of the present invention is
A radially expandable cylindrical bearing body,
And a resilient member mounted on the bearing main body and having a projection projecting outward from the outer peripheral surface of the bearing main body while being inclined with respect to the radial direction of the bearing main body.

Here, the slide bearing is
It is housed in a cylindrical housing and supports at least one of axial movement and rotation of the shaft member while supporting a load applied to the shaft member,
The elastic member is
When the slide bearing is accommodated in the housing, the protrusion may abut on an inner peripheral surface of the housing to bias the bearing main body radially inward.

  In the present invention, when the slide bearing is accommodated in, for example, a cylindrical housing, the radially outer end of the elastic member abuts against the inner peripheral surface of the housing to urge the bearing main body radially inward. Do. As a result, the diameter of the bearing body is reduced, and the shaft member inserted into the bearing body is tightened. At this time, the projecting portion of the elastic member abuts against the inner circumferential surface of the housing and is bent and deformed. Deterioration of an elastic body such as rubber or elastomer used for an elastic member is generally influenced by compressive deformation more than bending deformation. According to the present invention, since a part of the compressive stress applied to the elastic member can be released by bending deformation, the amount of compressive deformation can be reduced by that amount, thereby improving the durability of the elastic member. It is possible to extend the life.

FIG. 1 is a partial cross-sectional view of a part of a steering mechanism of a vehicle in which a rack bush 1 according to a first embodiment of the present invention is used. 2 (A), 2 (B) and 2 (C) are a front view, a side view and a rear view of the rack bush 1, respectively. 3 (A), 3 (B) and 3 (C) are a front view, a side view and a rear view of the bush main body 2, and FIGS. 3 (D) and 3 (E) are FIGS. It is AA sectional drawing and BB sectional drawing of the bush main body 2 shown to A), and FIG.3 (F) is the C section enlarged view of the bush main body 2 shown to FIG. 3 (A). 4 (A), 4 (B) and 4 (C) are a front view, a top view and a side view of the elastic member 3, and FIG. 4 (D) is an enlarged view of a portion D of FIG. 2 (A). FIG. 5 (A), 5 (B) and 5 (C) are a front view, a side view and a rear view of a rack bush 1 'according to a second embodiment of the present invention. 6 (A), 6 (B) and 6 (C) are a front view, a top view and a side view of the elastic member 3a, and FIG. 6 (D) is an E portion shown in FIG. 5 (B). 5C is an enlarged view in the direction of arrow F shown in FIG. 7A, 7B and 7C are a front view, a top view and a side view of the elastic member 3b, and FIG. 7D is an enlarged view of a portion G in FIG. 7C. FIG. FIG. 8 is a top view of the elastic member 3c.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment
FIG. 1 is a partial cross-sectional view of a part of a steering mechanism of a vehicle in which a rack bush 1 according to the present embodiment is used.

  As illustrated, the rack bush 1 according to the present embodiment is accommodated in the cylindrical housing 4 in a state in which the movement in the axial O direction is restricted, and the movement of the rack shaft 5 in the axial O direction is permitted. , Supports the load applied to the rack shaft 5.

  2 (A), 2 (B) and 2 (C) are a front view, a side view and a rear view of the rack bush 1, respectively.

  As illustrated, the rack bush 1 includes a cylindrical bush main body 2 into which the rack shaft 5 is inserted, and a plurality of elastic members 3 mounted on the bush main body 2.

  3 (A), 3 (B) and 3 (C) are a front view, a side view and a rear view of the bush main body 2, and FIGS. 3 (D) and 3 (E) are FIGS. It is AA sectional drawing and BB sectional drawing of the bush main body 2 shown to A), and FIG.3 (F) is the C section enlarged view of the bush main body 2 shown to FIG. 3 (A).

  The bush main body 2 is formed of a synthetic resin having good sliding characteristics such as polyacetal resin, polyamide resin, polyethylene resin, etc. and is formed on the inner peripheral surface 20 and inserted with the outer peripheral surface 50 of the rack shaft 5 as shown. The elastic member 3 is held by the sliding surface 21 in sliding contact, the plurality of first slits 25 and second slits 26 alternately arranged at equal intervals in the circumferential direction, the engagement portion 27 formed on the outer peripheral surface 22 And a plurality of holding grooves 28.

  The first slit 25 is formed along the axis O direction from one end face 23 toward the other end face 24, and the second slit 26 is along the axis O direction from the other end face 24 toward the one end face 23. It is formed. The bush main body 2 is easily deformed in the diameter reducing direction by the plurality of first slits 25 and the second slits 26 alternately arranged at equal intervals in the circumferential direction.

  The engaging portion 27 protrudes outward from the outer peripheral surface 22 on one end surface 23 side, and is inserted into an annular groove 41 formed in the inner peripheral surface 40 of the housing 4 in the circumferential direction. Thereby, the movement of the rack bush 1 accommodated in the housing 4 in the direction of the axis O is restricted.

  The holding groove 28 is formed on the outer peripheral surface 22 along the direction of the axis O so as to penetrate the both end surfaces 23 and 24. The holding groove 28 is formed such that the groove width W1 of the bottom 280 is wider than the groove width W2 of the opening 281.

  4 (A), 4 (B) and 4 (C) are a front view, a top view and a side view of the elastic member 3, and FIG. 4 (D) is an enlarged view of a portion D of FIG. 2 (A). FIG.

  The elastic member 3 is formed of an elastic body such as rubber or elastomer, and includes a held portion 31 and a pair of projecting portions 30 a and 30 b formed on the upper surface 310 of the held portion 31 as illustrated. There is.

  The protrusions 30a and 30b protrude outward from the outer peripheral surface 22 of the bush main body 2 in the rack bush 1, and the diameter D1 (see FIG. 2A) of a circle C connecting the apexes of the protrusions 30a and 30b is a housing The amount of protrusion from the upper surface 310 of the held portion 31 is set so as to be equal to the inner diameter D2 of 4 (see FIG. 1). Thus, when the rack bush 1 is accommodated in the housing 4, the elastic members 3 abut the protrusions 30 a and 30 b with the inner circumferential surface 40 of the housing 4 to bias the bush main body 2 radially inward. Do.

  Further, as shown in FIG. 4D, the projecting portions 30a and 30b of the elastic member 3 are circumferential to a straight line extending in the radial direction R through the center of the bush main body 2 in a cross section perpendicular to the axis O direction. It is inclined in the direction S. Therefore, when the rack bush 1 is accommodated in the housing 4, the projecting portions 30 a and 30 b contact the inner circumferential surface 40 of the housing 4 and bend and deform in the circumferential direction S. Further, the opening 281 of the holding groove 28 of the bush main body 2 is formed to have a groove width W2 capable of forming the accommodation regions 282a and 282b on both sides in the circumferential direction S of the protruding portions 30a and 30b of the elastic member 3 It is done. The projecting portions 30a, 30b which are bent in contact with the inner circumferential surface 40 of the housing 4 are accommodated in the accommodation regions 282a, 282b.

  The holding portion 31 has the same shape as the bottom portion 280 of the holding groove 28 of the bush main body 2 and slides the elastic member 3 in the direction of the axis O to place the holding portion 31 in the bottom portion 280 of the holding groove 28 The elastic member 3 is held in the holding groove 28 of the bush main body 2 by the insertion. Since the holding groove 28 of the bush main body 2 is formed such that the groove width W1 of the bottom 280 is wider than the groove width W2 of the opening 281, the elastic member 3 held in the holding groove 28 falls off in the radial direction Can be prevented.

  The first embodiment of the present invention has been described above.

  In the present embodiment, when the rack bush 1 is accommodated in the cylindrical housing 4, the projecting portions 30 a and 30 b of the elastic member 3 abut on the inner peripheral surface 40 of the housing 4 to make the bush main body 2 in the radial direction. Bias inward. As a result, the diameter of the bush main body 2 is reduced, and the rack shaft 5 inserted into the bush main body 2 is tightened. Here, since the projecting portions 30a and 30b of the elastic member 3 are inclined in the circumferential direction S with respect to the radial direction R in a cross section perpendicular to the axis O direction, at this time, with the inner circumferential surface 40 of the housing 4 It abuts and is bent and deformed in the circumferential direction S, and is accommodated in the accommodation areas 282a and 282b of the holding grooves 28 of the bush main body 2 formed on both sides of the projecting portions 30a and 30b in the circumferential direction S. Deterioration of an elastic body such as rubber or elastomer used for the elastic member 3 is generally affected by compressive deformation more than bending deformation. According to the present embodiment, when the rack bush 1 is accommodated in the housing 4, a part of the compressive stress applied to the elastic member 3 can be released by the bending deformation of the projecting portions 30a and 30b, so that the compression The amount of deformation can be reduced, whereby the durability of the elastic member 3 can be improved, and the life of the rack bush 1 can be extended.

  Further, in the present embodiment, the groove width W1 of the bottom 280 of the holding groove 28 of the bush main body 2 is made wider than the groove width W2 of the opening 281 and the held portion 31 of the elastic member 3 is used to hold the bush main body 2. The elastic member 3 is held by the holding groove 28 of the bush main body 2 by inserting the bottom portion 280 of the groove 28 into the bottom portion 280 of the holding groove 28 in the same shape. For this reason, it is possible to prevent the elastic member 3 held by the holding groove 28 of the bush main body 2 from falling in the radial direction.

  In addition, when the slide bearing described in Patent Document 1 is inserted into the housing 4, the slide bearing is supported by the housing 4 at a point in the direction of the axis O (1 point for one elastic ring, 2 for 2 rings). Point support), which may cause the outer peripheral surface of the bearing body to tilt in the axial direction O within the housing 4. In this respect, in the present embodiment, since the elastic member 3 extends in the direction of the axis O, when inserted into the housing 4, the elastic member 3 is supported by the housing 4 along the line in the direction of the axis O. The possibility of the outer peripheral surface 22 of 2 being inclined in the direction of the axis O in the housing 4 can be reduced.

  Furthermore, in the present embodiment, since the elastic member 3 has a shape utilizing bending deformation, there is an advantage that the degree of freedom in the shape is high, and the rigidity can be easily controlled.

Second Embodiment
Similarly to the rack bush 1 according to the first embodiment shown in FIG. 1, the rack bush 1 ′ according to the present embodiment is housed in the cylindrical housing 4 in a state in which the movement in the axial O direction is restricted. The load applied to the rack shaft 5 is supported while permitting the movement of the rack shaft 5 in the direction of the axis O.

  5 (A), 5 (B) and 5 (C) are a front view, a side view and a rear view of a rack bush 1 'according to a second embodiment of the present invention.

  The rack bush 1 'according to the present embodiment is different from the rack bush 1 according to the first embodiment in that an elastic member 3a is used instead of the elastic member 3. The other configuration is the same as that of the rack bush 1 according to the first embodiment.

  6 (A), 6 (B) and 6 (C) are a front view, a top view and a side view of the elastic member 3a, and FIG. 6 (D) is an E portion shown in FIG. 5 (B). 5C is an enlarged view in the direction of arrow F shown in FIG.

  The elastic member 3a is different from the elastic member 3 of the rack bush 1 according to the first embodiment in that it has a pair of engaging elastic portions 32a and 32b. The other configuration is the same as the elastic member 3 of the rack bush 1 according to the first embodiment.

  The engaging elastic portions 32a and 32b are formed on the upper surface 310 of the held portion 31 with the projecting portions 30a and 30b on the side of the engaging portion 27 of the bush main body 2, and are outward from the outer peripheral surface 22 of the bush main body 2. Stand out. Then, it is inserted into the annular groove 41 of the housing 4 together with the engagement portion 27 of the bush main body 2.

  The length L1 of the engaging elastic portions 32a and 32b in the axial O direction is longer than the length L2 of the engaging portion 27 of the bush main body 2 in the axial O direction, and the length of the annular groove 41 of the housing 4 in the axial O direction. It is set to be equal to L3 (see FIG. 1). However, if the engagement elastic parts 32a and 32b are shaped so that at least one end face protrudes from the end face of the engagement part 27 of the bush main body 2 in the direction of the axis O so as to be flush with the annular groove 41, The length L1 of the elastic portions 32a and 32b in the axis O direction may be shorter than the length L2 of the engaging portion 27 of the bush main body 2 in the axis O direction.

  The second embodiment of the present invention has been described above.

  In the present embodiment, at least one of the end faces of the engaging elastic portions 32a and 32b protrudes from the end face of the engaging portion 27 of the bush main body 2 in the direction of the axis O, and the engaging elastic portions 32a and 32b The length L1 in the direction of the axis O is set to be equal to the length L3 in the direction of the axis O of the annular groove 41 of the housing 4. Therefore, when the rack bush 1 is housed in the housing 4, the engagement portion 27 of the bush main body 2 can be prevented from repeatedly generating contact noise and non-contact with the side surface of the annular groove 41 of the housing 4 to generate noise. . Other effects are the same as those of the first embodiment of the present invention except that the outer peripheral surface of the bush main body 2 of the rack bush 1 ′ inserted in the housing 4 can reduce the possibility of tilting in the axial O direction in the housing 4 It is similar.

  The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the invention.

  For example, in each of the embodiments described above, the protrusions 30a and 30b of the elastic members 3 and 3a are inclined in the circumferential direction S with respect to the radial direction R in a cross section perpendicular to the axis O direction (FIG. See D). However, the present invention is not limited to this. The protrusions 30a and 30b of the elastic members 3 and 3a may be those protruding outward from the outer peripheral surface 22 of the bush main body 2 while being inclined with respect to the radial direction R. For example, as in the elastic member 3b shown in FIG. 7, the protrusion 30c inclined in the direction of the axis O with respect to the radial direction R in the cross section in the direction of the axis O You may provide in multiple numbers. In this case, it is preferable to provide the protrusion 30c at a predetermined interval so as to have a storage area 282c in which the protrusion 30c that is bent and deformed in contact with the inner circumferential surface 40 of the housing 4 is stored.

  Further, in each of the above-described embodiments, the groove width at both ends of the bottom 280 of the holding groove 28 of the bush main body 2 is wider than the groove width of the central portion sandwiched between the both ends, and any one of them. The groove width of the end on the side of the end face 23, 24 is inclined so as to narrow as it approaches the end face 23, 24, and in addition to this, as in the elastic member 3c shown in FIG. The width of the portions 311a and 311b may be wider than the width of the central portion 312 sandwiched between the end portions 311a and 311b, and the width of one end portion 311a may be inclined so as to narrow toward the end face 313. Then, the elastic member 3 may be held in the holding groove 28 of the bush main body 2 by inserting the held portion 31 into the bottom 280 of the holding groove 28 of the bush main body 2 with the end 311 a at the top. By doing this, it is possible to prevent the elastic member 3 c from sliding in the direction of the axis O and dropping out of the holding groove 28 of the bush main body 2 in the direction of the axis O.

  In each of the above embodiments, the holding groove 28 of the bush main body 2 is formed on the outer peripheral surface 22 of the bush main body 2 along the direction of the axis O, and the elastic members 3 and 3a to 3c are formed linearly. , Are held by the holding groove 28. However, the present invention is not limited to this. For example, the holding groove is formed in a ring shape along the circumferential direction on the outer peripheral surface 22 of the bush main body 2, and in this holding groove in the radial direction of the bush main body 2 in a cross section in the axis O direction or a cross section perpendicular to the axis O direction. An annular elastic member may be mounted that has a projecting portion that protrudes outward from the outer circumferential surface 22 while inclining against the outer circumferential surface 22 and that abuts against the inner circumferential surface 40 of the housing 4.

  Further, in each of the above-described embodiments, a plurality of first slits 25 are formed in the bush main body 2 from the one end face 23 toward the other end face 24 along the direction of the axis O, and from the other end face 24 A plurality of second slits 26 are formed along the direction of the axis O toward the end face 23 of the optical axis. However, the present invention is not limited to this. The bush main body 2 should just have a cylindrical shape which can be expanded and contracted in the radial direction. For example, by providing a slit formed along the direction of the axis O from any one end face to the other end face, it may be radially expandable or a thin portion may be provided instead of the slit. It may be able to expand and contract in the radial direction.

  Moreover, although the shape of the bush main body 2 is made into cylindrical shape in said each embodiment, it should just be a cylindrical shape which adapts the shape of the rack shaft 5 inserted. Further, in the present embodiment, the bush main body 2 and the elastic members 3 and 3a to 3c are formed of different materials, but both may be formed of the same material.

  Also, the present invention is not limited to the rack bush. The present invention is widely applicable to a slide bearing that supports the load applied to the shaft member while allowing at least one of axial movement and rotation of the shaft member. For example, the present invention can be applied to a steering column bush that supports the load applied to the steering column while allowing rotation of the steering column.

  1, 1 ': rack bush, 2: bush main body, 3, 3a to 3c: elastic member, 4: housing, 5: rack shaft, 20: inner circumferential surface of bush main body 2, 21: sliding face of bush main body 2 , 22: outer peripheral surface of the bush body 2, 23, 24: end face of the bush body 2, 25: first slit, 26: second slit, 27: engaging portion, 28: holding groove, 30a to 30c: projecting portion, 31: held portion 32a, 32b: elastic portion for engagement, 40: inner circumferential surface of housing 4, 41: annular groove, 50: outer circumferential surface of rack shaft 5, 280: bottom portion of holding groove 28, 281: holding groove 28 openings 282a to 282c: accommodation area 310: upper surface of held portion 31 313: end surface of elastic member 3c

Claims (7)

A radially expandable cylindrical bearing body,
And a resilient member mounted on the bearing main body and having a projection projecting outward from the outer peripheral surface of the bearing main body while being inclined with respect to the radial direction of the bearing main body. . The sliding bearing according to claim 1, wherein the bearing body is
A slide bearing characterized by having a slit formed along an axial direction from one end face to the other end face. The sliding bearing according to claim 1 or 2, wherein
The sliding bearing is
It is accommodated in a cylindrical housing and supports at least one of axial movement and rotation of the shaft member while supporting a load applied to the shaft member,
The elastic member is
A sliding bearing characterized in that when the sliding bearing is accommodated in the housing, the projection abuts against the inner circumferential surface of the housing to bias the bearing main body radially inward. The sliding bearing according to claim 3, wherein
The bearing body is
It further has an engaging portion that protrudes outward from the outer peripheral surface at one end and is inserted into an annular groove formed in the circumferential direction on the inner peripheral surface of the housing,
The elastic member is
A slide bearing characterized by further comprising an elastic part for engagement which is inserted into the annular groove of the housing together with the engagement portion of the bearing main body and abuts on a side surface of the annular groove. A sliding bearing according to any one of claims 1 to 4, wherein
The bearing body is
And a holding groove formed on the outer peripheral surface, the groove width at the bottom being wider than the groove width at the opening,
The elastic member is
A slide bearing, which is accommodated in the holding groove of the bearing main body, and further includes a held portion having the same shape as the holding groove. The sliding bearing according to claim 5, wherein
The holding groove of the bearing main body and the held portion of the elastic member are:
The groove is formed along the axial direction from one end face to the other end face of the bearing main body, and the groove width at both ends is wider than the groove width of the middle part sandwiched between the both ends, and the groove at one end face A sliding bearing characterized in that the width is narrowed as it approaches the one end face. A sliding bearing according to claim 5 or 6, wherein
The holding groove of the bearing body is
A sliding bearing comprising a housing area for housing the bent portion of the elastic member.

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