JP2018155390A - Slide bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slide bearing which can be manufactured at a lower cost by reducing the number of parts and the assembly man-hours. SOLUTION: A rack bush 1 is housed in a cylindrical housing and supports a load applied to the rack shaft while allowing the rack shaft 5 to move in the axis O direction, and the rack shaft is inserted. It includes a tubular bush body 2 and a diameter-reducing elastic member 3 that is integrally formed with the bush body 2 and projects radially outward from the outer peripheral surface of the bush body 2. The bush body 2 has a slit formed along the axis O direction from one end face to the other end face. When the rack bush 1 is housed in the housing, the radial elastic member 3 abuts the radial outer end portion on the inner peripheral surface of the housing and urges the bush body 2 in the radial direction. .. [Selection diagram] Fig. 2

Description

  The present invention relates to a slide bearing that supports a load applied to a shaft member while allowing the shaft member to move in the axial direction, 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 sliding bearing suitable for a rack bush used for a steering mechanism of a vehicle, it is accommodated in a cylindrical housing in a state in which axial movement is restricted, and the rack shaft is allowed to move in the axial direction. However, a sliding bearing that supports a load applied to the rack shaft is described.

  The sliding bearing includes a cylindrical bearing body into which a rack shaft is inserted, and an elastic ring that is attached to the bearing body and biases the bearing body radially inward. The bearing body is made of synthetic resin, and is formed along the axial direction from the one end surface toward the other end surface along the axial direction and from the other end surface toward the one end surface. And a mounting groove formed on the outer peripheral surface of the bearing body and mounted with an elastic ring.

  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. Further, it is possible to prevent the generation of unpleasant noise due to the collision between the inner peripheral surface of the bearing body and the outer peripheral surface of the rack shaft, and it is possible to prevent the variation of the friction torque due to the outer diameter dimension error of the rack shaft.

Japanese Patent No. 2008-151289

  However, in the sliding bearing described in Patent Document 1, since the bearing body and the elastic ring are separate parts, the number of parts increases and the part management costs. Further, since it is necessary to mount the elastic ring in the mounting groove formed on the outer peripheral surface of the bearing body, the number of assembling steps is increased and the assembling work is costly.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a slide bearing that can be manufactured at a lower cost by reducing the number of parts and the number of assembly steps.

  In order to solve the above problems, in the sliding bearing of the present invention, a cylindrical bearing body into which the shaft member is inserted is provided with a slit formed along the axial direction from one end surface to the other end surface. The elastic member for reducing diameter is provided integrally with the bearing body and protrudes radially outward from the outer peripheral surface. When this sliding bearing is housed in, for example, a cylindrical housing, the radially outer end of the elastic member for diameter reduction comes into contact with the inner peripheral surface of the housing, and the bearing body is moved radially inward. The protruding amount of the elastic member for diameter reduction protruding from the outer peripheral surface of the bearing body is set so as to be biased.

For example, the sliding bearing of the present invention is
A cylindrical bearing body having a slit formed along the axial direction from one end surface to the other end surface, and capable of expanding and contracting in the radial direction;
A diameter-reducing elastic member formed integrally with the bearing body and projecting radially outward from the outer peripheral surface of the bearing body.

Here, the sliding bearing is
It is accommodated in a cylindrical housing and supports the load applied to the shaft member while allowing the shaft member to move in the axial direction.
The elastic member for diameter reduction is
When the sliding bearing is accommodated in the housing, the radially outer end may abut against the inner peripheral surface of the housing to urge the bearing body radially inward.

  In the present invention, when the sliding bearing is accommodated in, for example, a cylindrical housing, the radially outer end of the elastic member for diameter reduction comes into contact with the inner peripheral surface of the housing, so that the bearing body is radially inward. Energize to. For this reason, by accommodating the sliding bearing in the housing, the bearing main body is reduced in diameter, and the shaft member inserted into the bearing main body is tightened. Therefore, it is not necessary to attach an elastic ring to the bearing main body. Further, since the elastic member for diameter reduction is formed integrally with the bearing main body, it is not necessary to manage parts as separate parts for the bearing main body and the elastic member for diameter reduction. Therefore, according to the present invention, it is possible to provide a plain bearing that can be manufactured at a lower cost by reducing the number of parts and the number of assembly steps.

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

  Embodiments of the present invention will be described below with reference to the drawings.

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

  As shown in the figure, the rack bush 1 according to the present embodiment is accommodated in a cylindrical housing 4 in a state in which movement in the axis O direction is restricted, while allowing the rack axis 5 to move in the axis O direction. The load applied to the rack shaft 5 is supported.

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

  As shown in the figure, the rack bush 1 includes a cylindrical bush body 2 into which the rack shaft 5 is inserted, and a plurality of elastic members for reducing diameter formed integrally with the bush body 2 by two-color molding, insert molding, or the like. 3 is provided.

  FIGS. 3A, 3B, and 3C are a front view, a side view, and a rear view of the bush body 2, and FIGS. 3D and 3E are FIGS. FIGS. 3A and 3B are an AA sectional view and a BB sectional view of the bush main body 2 shown in FIG. 3A, and FIG. 3F is an enlarged view of a portion C of the bush main body 2 shown in FIG.

  The bush body 2 is made 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 into the outer peripheral surface 50 of the rack shaft 5 as shown in the figure. A sliding surface 21 that is in sliding contact, a plurality of first slits 25 and second slits 26 that are alternately arranged at equal intervals in the circumferential direction, an engagement portion 27 formed on the outer peripheral surface 22, and an elastic member for diameter reduction. A plurality of holding grooves 28 for holding 3.

  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 formed along the axis O direction from the other end face 24 toward the one end face 23. Is formed. The bush body 2 can be deformed in the reduced diameter direction by a plurality of first slits 25 and second slits 26 alternately arranged at equal intervals in the circumferential direction.

  The engaging portion 27 projects radially outward from the outer peripheral surface 22 on one end surface 23 side, and is inserted into an annular groove 41 formed in the circumferential direction on the inner peripheral surface 40 of the housing 4. 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 axis O direction so as to penetrate the both end surfaces 23 and 24. The holding groove 28 is formed so 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 for diameter reduction, and FIG. 4 (D) is a view of FIG. 2 (A). It is a D section enlarged view.

  The diameter-reducing elastic member 3 is formed of a thermoplastic elastomer such as polyurethane elastomer that can be integrally formed with the bushing body 2 by two-color molding, insert molding, or the like. A pair of projecting portions 30 a and 30 b formed on the upper surface 310 of the portion 31.

  The protrusions 30a and 30b protrude radially outward from the outer peripheral surface 22 of the bush body 2 in the rack bush 1 and have a diameter D1 (see FIG. 2A) of a circle C connecting the vertices of the protrusions 30a and 30b. The amount of protrusion from the upper surface 310 of the held portion 31 is set so that the inner diameter D <b> 2 of the housing 4 (see FIG. 1) is squeezed. Thereby, when the rack bush 1 is accommodated in the housing 4, the elastic member 3 for reducing the diameter contacts the inner peripheral surface 40 of the housing 4 with the protrusions 30 a and 30 b so that the bush main body 2 is radially inward. Energize to.

  4D, the protrusions 30a and 30b of the diameter-reducing 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. For this reason, when the rack bush 1 is accommodated in the housing 4, the projecting portions 30 a and 30 b abut against the inner peripheral 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 body 2 has a width W2 of a groove width wider than the protrusions 30a and 30b of the elastic member 3 for diameter reduction, and thereby the circumferential direction of the protrusions 30a and 30b. Storage areas 282a and 282b are formed on both sides of S. The protruding portions 30a and 30b that are bent and deformed in contact with the inner peripheral surface 40 of the housing 4 are accommodated in the accommodating regions 282a and 282b.

  The held portion 31 has the same shape as the bottom portion 280 of the holding groove 28 of the bush body 2 and is accommodated in the bottom portion 280 of the holding groove 28. For this reason, even when the diameter-reducing elastic member 3 formed integrally with the bushing body 2 is peeled off from the bushing body 2, the diameter-reducing elastic member 3 is prevented from coming off from the holding groove 28 of the bushing body 2 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 housed in the cylindrical housing 4, the protrusions 30 a and 30 b of the elastic member 3 for diameter reduction come into contact with the inner peripheral surface 40 of the housing 4, and the bush body 2 Is urged radially inward. For this reason, by accommodating the rack bush 1 in the housing 4, the bush main body 2 is reduced in diameter, and the rack shaft 5 inserted into the bush main body 2 is tightened, so there is no need to attach an elastic ring to the bush main body 2. . Further, since the diameter-reducing elastic member 3 is formed integrally with the bush main body 2, there is no need to manage the parts as a separate part. Therefore, according to the present embodiment, it is possible to provide the rack bush 1 that can be manufactured at a lower cost by reducing the number of parts and the number of assembly steps.

  Further, in the present embodiment, the protrusions 30a and 30b of the diameter-reducing 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. When accommodated in the housing 4, the holding groove 28 of the bush main body 2 formed on both sides of the projecting portions 30 a and 30 b in the circumferential direction S is brought into contact with the inner peripheral surface 40 of the housing 4 to bend and deform in the circumferential direction S. Are accommodated in the accommodating areas 282a and 282b. The deterioration of the thermoplastic elastomer used for the elastic member 3 for diameter reduction is generally more influenced by the compression deformation than the bending deformation. In the present embodiment, a part of the compressive stress applied to the elastic member 3 for reducing the diameter when the rack bush 1 is accommodated in the housing 4 can be released by the bending deformation of the protruding portions 30a and 30b. The amount of compressive deformation can be reduced, whereby the durability of the elastic member 3 for diameter reduction can be improved.

  In the present embodiment, the groove width W1 of the bottom portion 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 for reducing diameter is The holding groove 28 has the same shape as the bottom 280 of the holding groove 28 and is accommodated in the bottom 280 of the holding groove 28. For this reason, even when the diameter-reducing elastic member 3 formed integrally with the bushing body 2 is peeled off from the bushing body 2, the diameter-reducing elastic member 3 is prevented from coming off from the holding groove 28 of the bushing body 2 in the radial direction. Can be prevented.

  Further, in the sliding bearing described in Patent Document 1, an elastic ring that urges the bearing body radially inward is mounted in the mounting groove of the bearing body. For this reason, when the sliding bearing is inserted into the housing 4, a force in a direction away from the mounting groove is applied to the elastic ring, and the elastic ring may be detached from the mounting groove. However, in the present embodiment, since the elastic member 3 for diameter reduction is formed integrally with the bush main body 2 along the axis O direction, there is no such concern. Therefore, according to the present embodiment, it is possible to improve the workability of the work of inserting the rack bush 1 into the housing 4.

  Further, when the plain bearing described in Patent Document 1 is inserted into the housing 4, it is supported by the housing 4 at a point in the direction of the axis O (one point is supported if there is one elastic ring, and two points if it is two). For this reason, there is a possibility that the outer peripheral surface of the bearing body is inclined in the axis O direction within the housing 4. In this respect, in this embodiment, since the elastic member 3 for diameter reduction extends in the direction of the axis O, when inserted into the housing 4, it is supported by the housing 4 with a line in the direction of the axis O. The possibility that the outer peripheral surface 22 of the bush body 2 is inclined in the axis O direction in the housing 4 can be reduced.

  Furthermore, in the present embodiment, since the diameter-reducing elastic member 3 has a shape utilizing bending deformation, there is an advantage that the degree of freedom of 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 also housed in the cylindrical housing 4 in a state in which movement in the axis O direction is restricted, The load applied to the rack shaft 5 is supported while allowing the rack shaft 5 to move in the axis O direction.

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

  The difference between the rack bush 1 ′ according to the present embodiment and the rack bush 1 according to the first embodiment is that a diameter-reducing elastic member 3 a is used instead of the diameter-reducing elastic member 3. Other configurations are the same as those of the rack bush 1 according to the first embodiment.

  FIGS. 6A, 6B, and 6C are a front view, a top view, and a side view of the elastic member 3a for reducing the diameter, and FIG. 6D is shown in FIG. 5B. It is the F direction arrow enlarged view shown to FIG. 5 (C) of the E section shown.

  The diameter-reducing elastic member 3a is different from the diameter-reducing 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. Other configurations are the same as those of the elastic member 3 for reducing the diameter of the rack bush 1 according to the first embodiment.

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

  The length L1 of the engagement elastic portions 32a and 32b in the axis O direction is longer than the length L2 of the engagement portion 27 of the bush body 2 in the axis O direction, and the length of the annular groove 41 of the housing 4 in the axis O direction. The length L3 (see FIG. 1) is set to be squeezed. However, the engaging elastic portions 32a and 32b have an engaging shape as long as at least one end surface protrudes from the end surface of the engaging portion 27 of the bush main body 2 so as to form the annular groove 41 in the axis O direction. 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 body 2 in the axis O direction.

  Here, the engaging elastic portions 32a and 32b are formed integrally with the diameter-reducing elastic member 3a. However, the engaging elastic portions 32a and 32b are formed integrally with the bush main body 2. It may be sufficient, and may be a separate part from the elastic member 3a for diameter reduction.

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

  In the present embodiment, the engaging elastic portions 32a and 32b are shaped so that at least one end surface protrudes from the end surface of the engaging portion 27 of the bush body 2 in the axis O direction, and the engaging elastic portions 32a and 32b The length L1 in the axis O direction is set so as to be squeezed with respect to the length L3 in the axis O direction of the annular groove 41 of the housing 4. For this reason, when the rack bush 1 is accommodated in the housing 4, it is possible to prevent the engaging portion 27 of the bush body 2 from repeatedly making contact and non-contact with the side surface of the annular groove 41 of the housing 4 and generating abnormal noise. . Other effects are the same as those of the first embodiment of the present invention.

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

  For example, in each of the embodiments described above, the protrusions 30a and 30b of the diameter-reducing 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 ( (See FIG. 4D). However, the present invention is not limited to this. Like the elastic member for diameter reduction 3b shown in FIG. 7, the protrusion 30c inclined in the axis O direction with respect to the radial direction R in the cross section in the axis O direction is formed on the upper surface of the held portion 31 along the axis O direction. A plurality may be provided in 310. In this case, it is preferable to provide the projecting portions 30c with a predetermined interval so as to have an accommodating region 282c in which the projecting portion 30c bent and deformed in contact with the inner peripheral surface 40 of the housing 4 is accommodated.

  In each of the above embodiments, the groove width at both ends of the bottom portion 280 of the holding groove 28 of the bush body 2 is made wider than the groove width at the center portion sandwiched between the both ends, Like the elastic member 3 c for diameter reduction shown in FIG. 8, the width at the both end portions 311 of the held portion 31 may be wider than the width of the central portion 312 sandwiched between the both end portions 311. Thus, even when the diameter-reducing elastic member 3c formed integrally with the bushing body 2 is peeled off from the bushing body 2, the diameter-reducing elastic member 3c slides in the direction of the axis O and the bushing body 2 Can be prevented from falling off from the holding groove 28 in the direction of the axis O.

  Further, in each of the above-described embodiments, a plurality of first slits 25 are formed in the bushing body 2 from the one end face 23 toward the other end face 24 along the axis O direction, and one end from the other end face 24 is one. A plurality of second slits 26 are formed in the direction of the axis O toward the end surface 23. However, the present invention is not limited to this. The bush main body 2 may be provided with a slit formed along the axis O direction from one end face to the other end face. Moreover, in each said embodiment, although the shape of the bush main body 2 is made into cylindrical shape, what is necessary is just a cylinder shape suitable for the shape of the rack axis | shaft 5 inserted. Moreover, in this Embodiment, although the bush main body 2 and the elastic member 3 for diameter reduction, 3a-3c are formed with a different material, you may form both with the same material.

  Further, the present invention is not limited to the rack bush. The present invention is widely applicable to a sliding bearing that supports a load applied to the shaft member while allowing the shaft member to move.

  DESCRIPTION OF SYMBOLS 1, 1 ': Rack bush, 2: Bush main body 3, 3a-3c: Elastic member for diameter reduction, 4: Housing, 5: Rack shaft, 20: Inner peripheral surface of bush main body 2, 21: Bush main body 2 Sliding surface, 22: outer peripheral surface of the bush body 2, 23, 24: end surface of the bush body 2, 25: first slit, 26: second slit, 27: engagement portion, 28: holding groove, 30a to 30c: Projection part 31: Held part 32a, 32b: Elastic part for engagement 40: Inner peripheral surface of housing 4 41: Annular groove 50: Outer peripheral surface of rack shaft 5 280: Bottom part of holding groove 28 281 : Opening portion of holding groove 28, 282a to 282c: accommodation region, 310: upper surface of held portion 31

Claims (8)

A cylindrical bearing body having a slit formed along the axial direction from one end surface to the other end surface, and capable of expanding and contracting in the radial direction;
A sliding bearing, comprising: an elastic member for reducing diameter formed integrally with the bearing body and projecting radially outward from an outer peripheral surface of the bearing body. The sliding bearing according to claim 1,
The sliding bearing is
It is accommodated in a cylindrical housing and supports the load applied to the shaft member while allowing the shaft member to move in the axial direction.
The elastic member for diameter reduction is
When the sliding bearing is housed in the housing, the radially outer end abuts against the inner peripheral surface of the housing to urge the bearing body radially inward. bearing. The sliding bearing according to claim 2,
The elastic member for diameter reduction is
A sliding bearing comprising: a projecting portion projecting radially outward while inclining with respect to a radial direction in a cross section in an axial direction or a cross section perpendicular to the axial direction and contacting an inner peripheral surface of the housing. A sliding bearing according to claim 2 or 3,
The bearing body further includes an engaging elastic member formed integrally with the bearing body.
It further has an engaging portion that protrudes radially 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 engaging elastic member is:
A sliding bearing, wherein the sliding bearing is inserted into the annular groove of the housing together with the engaging portion of the bearing body, and abuts against a side surface of the annular groove. The sliding bearing according to claim 4,
The sliding elastic member, wherein the engaging elastic member is integrated with the reduced diameter elastic member. A sliding bearing according to any one of claims 1 to 5,
The bearing body is
Formed on the outer peripheral surface, further having a holding groove whose bottom groove width is wider than the groove width of the opening,
The elastic member for diameter reduction is
A sliding bearing, further comprising a held portion that is housed in the holding groove of the bearing body and has the same shape as the holding groove. The sliding bearing according to claim 6,
The holding groove of the bearing body and the held portion of the elastic member for diameter reduction are
A sliding bearing, characterized in that it is formed along the axial direction from one end surface of the bearing body to the other end surface, and the groove width at both ends is wider than the groove width at the intermediate portion sandwiched between the both ends. A sliding bearing according to claim 6 or 7,
The holding groove of the bearing body is
A sliding bearing comprising: a housing region that houses a bent part of the elastic member for diameter reduction.

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