JP2009024740A - Synthetic resin slide bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin slide bearing which reduces stress relaxation accompanying a heat history by a temperature rise inside a gear casing, and realizes a smooth steering operation in such a condition that no beat is generated between a rack shaft and a bearing, and that a sliding resistance between the rack shaft and the bearing is small even in the steering operation in which a radial force acts on the rack shaft. <P>SOLUTION: A synthetic resin slide bearing 30 integrally comprises: three semicircle cylindrical segments 31a, 31b and 31c arranged in circumferential direction X; and thin wall connecting pieces 32a, 32b and 32c which mutually connect, in the circumferential direction X, semicircle cylindrical segments 31a, 31b and 31c mutually adjacent in the circumferential direction X, and are more thinned than the semicircle cylindrical segments 31a, 31b and 31c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a synthetic resin sliding bearing, and more particularly to a synthetic resin sliding bearing suitable for slidingly supporting a rack shaft in an automobile steering mechanism.

Japanese Utility Model Publication No. 62-34028 Actual application No. 4-25081 microfilm

  A rack and pinion type steering device in a vehicle such as an automobile rotates a pinion shaft connected thereto by rotation of a steering wheel (handle), and slides a rack shaft meshing with the pinion shaft in a left-right direction in a gear case, The steering wheel connected to this is steered.

  As means for slidably supporting the rack shaft in such a rack and pinion type steering device in the gear case, for example, as shown in FIG. 12, the outer peripheral surface 10 and the inner peripheral surface 12 of the gear case 11 are connected. A contact surface 13 having a semi-cylindrical shape and a flat non-contact surface 14 that does not contact the inner peripheral surface 12 of the gear case 11 are alternately provided in the circumferential direction, and a locking projection 15 is provided at a substantially central portion of the contact surface 13. A rack shaft (not shown) disposed on the inner peripheral surface 16 corresponding to the non-contact surface 14 that does not contact the inner peripheral surface 12 of the gear case 11 and disposed in the inner peripheral surface 16. A flat fastening allowance bearing surface 19 that slides in contact with the peripheral surface with a predetermined allowance to support the rack shaft and a contact surface 13 that contacts the inner peripheral surface 12 of the gear case 11 are arranged. Without the rack shaft circumference and tightening allowance There is a bearing 21 made of a synthetic resin having elasticity and a semi-cylindrical non interference with the bearing surface 20 alternately in a circumferential direction for supporting the rack shaft in contact (Patent Document 1 Shosai).

  In the bearing 21, a gap 22 is formed between the non-contact surface 14 of the bearing 21 and the inner peripheral surface 12 of the gear case 11 to absorb dimensional errors and to distribute air. However, since the radial thickness is reduced at the portion of the non-contact surface 14, the rigidity of the portion is low. For example, when a radial force is applied to the rack shaft during a steering operation, the clearance 22 In the steering operation in a state where a radial force is applied to the rack shaft, the rack shaft is bent at a portion corresponding to the radial direction in the radial direction and a hitting sound is generated between the rack shaft and the bearing 21. There is a problem that the sliding resistance between the bearing 21 and the bearing 21 increases, and the steering operation becomes heavy, and that the displacement of the rack shaft is large due to the bearing 21 itself being made of elastic synthetic resin.

  In order to solve the above-described problems, a protrusion that contacts the inner peripheral surface 12 of the gear case 11 is provided on a part of the non-contact surface 14 that does not contact the inner peripheral surface 12 of the gear case 11, The rigidity of the portion of the bearing 21 on the non-contact surface 14 that contacts the inner peripheral surface 12 of the gear case 11 is increased, the radial load applied to the rack shaft is supported, vibration of the rack shaft is suppressed, and the rack shaft There has been proposed a bearing made of a synthetic resin that does not generate a gap with the outer peripheral surface of the shaft and can effectively prevent a hitting sound generated between the rack shaft and the bearing 21 (Patent Document 2).

  The above-described bearing made of synthetic resin does not generate a hitting sound between the rack shaft and the bearing, and the steering shaft is operated between the rack shaft and the bearing even in a radial force applied to the rack shaft. Although smooth steering operation is possible, in particular, since the steering gear box in the electric power steering device is mounted in the vicinity of the engine of the vehicle, when the bearing is arranged on the inner peripheral surface of the gear case, The gear case is forced to receive a thermal history due to the temperature rise, and due to stress relaxation due to the thermal history, the predetermined interference between the rack shaft and the bearing disappears, reducing the elastic support force of the rack shaft and reducing the rack shaft A new problem of generating hitting noise between the bearing and the bearing is raised.

  The present invention has been made in view of the above-described points, and an object of the present invention is to reduce stress relaxation associated with a thermal history due to a temperature rise in the gear case, and to reduce the clearance between the rack shaft and the bearing. Synthetic resin that enables smooth steering operation with low sliding resistance between the rack shaft and the bearing even in the steering operation with radial force acting on the rack shaft, without generating hitting sound It is to provide a plain bearing.

  The synthetic resin sliding bearing of the present invention interposed between the rack shaft and the gear case to support the rack shaft movably in the gear case has at least three semi-cylindrical shapes arranged in the circumferential direction. Each of the semi-cylindrical divided pieces that are adjacent to each other in the circumferential direction is connected in the circumferential direction and is formed thinner than the semi-cylindrical divided pieces. The outer peripheral surface of the cylindrical divided piece has a pair of contact surfaces that contact the inner peripheral surface of the gear case and a non-contact surface that does not contact the inner peripheral surface of the gear case. The inner peripheral surface of the shaft is provided at a position corresponding to the non-contact surface in the radial direction, and a tightening shaft support for supporting the rack shaft by slidingly contacting the peripheral surface of the rack shaft with a predetermined tightening allowance. Surface and radial direction with the tightening shaft support surface in the circumferential direction The non-tightening shaft bearing is provided at a position corresponding to the contact surface and is slidably in contact with the peripheral surface of the rack shaft without having a tightening margin. A non-contact surface of the outer peripheral surface of each semi-cylindrical divided piece has a belt-like protrusion extending along the axial direction as a fastening allowance shaft supporting surface in the radial direction. Correspondingly, they are integrally provided.

  According to the synthetic resin sliding bearing of the present invention, the rack shaft is arranged corresponding to the radial direction on the non-contact surface that does not contact the inner peripheral surface of the gear case, and the tightening margin arranged in the circumferential direction. Non-tightening bearings with a predetermined tightening allowance on the shaft support surface and arranged in the circumferential direction with the tightening allowance shaft support surface in between and provided in a position corresponding to the contact surface in the radial direction The shaft is slidably supported in the axial direction without any tightening allowance, and the non-contact surface that does not contact the inner peripheral surface of the gear case of the semi-cylindrical divided piece is also provided with a tightening allowance shaft in the radial direction. A belt-shaped protrusion is provided corresponding to the bearing surface to increase the radial rigidity of the non-contact surface that does not contact the inner peripheral surface of the gear case, so that the rack shaft is unlikely to be bent during steering operation. Struck between the rack shaft and synthetic resin sliding bearing In addition, even when the gear case is subjected to expansion or contraction due to a thermal history due to a temperature rise in the gear case, the expansion and contraction can be achieved by connecting the semi-cylindrical divided pieces to each other in the circumferential direction. Is absorbed by the expansion and contraction in the circumferential direction accompanied by the overhang in the radial direction, so that the predetermined tightening margin with the rack shaft is not lost due to the stress relaxation due to the thermal history, and the elastic supporting force of the rack shaft is reduced. No hitting noise is generated between the rack shaft and the synthetic resin sliding bearing.

  The semi-cylindrical divided piece is obtained by dividing a cylindrical body into at least three parts in the circumferential direction, and at least one of the thin-walled connecting pieces that connect the semi-cylindrical divided pieces to each other in the circumferential direction. The axial width of the two thin connecting pieces is such that, in cooperation with a pair of semi-cylindrical divided pieces connected by the at least one thin connecting piece, a slit groove is formed at both ends in the axial direction. It is preferable that it is narrower than the axial width of the semi-cylindrical divided piece.

  The at least one thin connecting piece has a bent portion that folds radially outward in the central portion and has a V-shape when viewed from the axial direction. Even if it has a bent portion that folds in the direction and has a V shape when viewed from the axial direction, it further has a curved portion that protrudes radially outward at the center and from the axial direction. It may be U-shaped when viewed, and may have a curved portion protruding inward in the radial direction at the center and may be U-shaped when viewed from the axial direction.

  The thin connecting piece has an effect of absorbing expansion and contraction by expansion and contraction in the circumferential direction when the synthetic resin sliding bearing is subjected to expansion and contraction due to a thermal history due to a temperature rise in the gear case. The V-shaped or U-shaped thin connecting piece as viewed from the axial direction exhibits such an absorption effect more preferably.

  The inner circumferential surface of each semi-cylindrical divided piece has one semi-cylindrical surface extending in the axial direction from one end face of the semi-cylindrical divided piece, and the axial direction of the shaft bearing surface from the end of the one semi-cylindrical face. One tapered surface extending to one end of the semi-cylindrical portion and gradually decreasing in diameter, the other semi-cylindrical surface extending in the axial direction from the other end surface of the semi-cylindrical divided piece, and a shaft bearing from the end of the other semi-cylindrical surface It is preferable to have the other tapered surface that extends to the other end in the axial direction of the surface and gradually decreases in diameter.

  According to the synthetic resin sliding bearing having the semi-cylindrical surface and the tapered surface on the inner peripheral surface of the semi-cylindrical divided piece, the rack shaft can be easily mounted from the tapered surface side, so that the number of assembling steps can be reduced. Can do.

  A plurality of indents may be formed on the shaft support surface of the inner peripheral surface of at least one semi-cylindrical divided piece, and in particular, a plurality of indents may be formed on the tightening allowance shaft support surface among the shaft support surfaces. Is good to be formed.

  The plurality of indents formed on the shaft support surface serve as a reservoir for a lubricant such as grease, so that the rack shaft slidably supported on the shaft support surface can slide more smoothly.

  It is preferable that the outer peripheral surface of each semi-cylindrical divided piece is provided with a locking projection that fits into the inner peripheral surface of the gear case.

  The projection is fitted into a hole or recess formed in the inner peripheral surface of the gear case when the synthetic resin sliding bearing is fixed to the inner peripheral surface of the gear case. This is effective for positioning the sliding bearing on the inner peripheral surface of the gear case.

  As the synthetic resin for forming the synthetic resin sliding bearing, thermoplastic resins such as polyacetal resin and polyamide resin, polyester elastomer, polyurethane elastomer, and the like are preferably used.

  According to the present invention, it is possible to reduce the stress relaxation associated with the thermal history due to the temperature rise in the gear case, and a radial force is applied to the rack shaft without generating a hitting sound between the rack shaft and the bearing. It is possible to provide a synthetic resin sliding bearing in which the sliding resistance between the rack shaft and the bearing is small even during the steering operation in the acted state and the smooth steering operation is possible.

  Next, an example of an embodiment of the present invention will be described in more detail based on an example shown in the figure. The present invention is not limited to these examples.

  1 to 5, the synthetic resin sliding bearing 30 of this example interposed between the rack shaft 39 and the gear case 34 to support the rack shaft 39 so as to be movable in the gear case 34 is circular. Three semi-cylindrical divided pieces 31a, 31b, and 31c arranged in the circumferential direction X and semi-cylindrical divided pieces 31a, 31b, and 31c adjacent to each other in the circumferential direction X are connected to each other in the circumferential direction X and half Thinly connected pieces 32a, 32b, and 32c that are formed thinner than the cylindrical divided pieces 31a, 31b, and 31c are integrally provided.

  Each of the semi-cylindrical outer peripheral surfaces 33a, 33b, and 33c of the semi-cylindrical divided pieces 31a, 31b, and 31c is a pair of semi-cylindrical contact surfaces 36a that contact the cylindrical inner peripheral surface 35 of the gear case 34, 36b and 36c, and non-contact surfaces 37a, 37b, and 37c that surround each of the pair of contact surfaces 36a, 36b, and 36c and that do not contact the inner peripheral surface 35 of the gear case 34, respectively.

  In the pair of contact surfaces 36a, 36b, and 36c that are larger in diameter than the non-contact surfaces 37a, 37b, and 37c and are arranged in the circumferential direction X, the contact surface 36a and the one contact surface 36a are circumferential. One contact surface 36b adjacent in the direction X is arranged with the thin connecting piece 32a sandwiched in the circumferential direction X, and the other contact surface 36b and the other contact surface 36b are adjacent in the circumferential direction X. The contact surface 36c is arranged with the thin connecting piece 32b sandwiched in the circumferential direction X, and the other contact surface 36c and the other contact surface 36a adjacent to the other contact surface 36c in the circumferential direction X are In the circumferential direction X, the thin connecting pieces 32c are interposed therebetween.

  The inner peripheral surfaces 38a, 38b, and 38c of the semi-cylindrical divided pieces 31a, 31b, and 31c respectively correspond to the non-contact surfaces 37a, 37b, and 37c between the pair of contact surfaces 36a, 36b, and 36c in the radial direction. Flat fastening allowance shaft support surfaces 41a, 41b and 41c which are provided at positions and which slidably contact the cylindrical peripheral surface 40 of the rack shaft 39 with a predetermined fastening allowance to support the rack shaft 39. In the circumferential direction X, the clamping allowance shaft support surfaces 41a, 41b and 41c are provided at positions corresponding to the contact surfaces 36a, 36b and 36c in the radial direction, and the fastening allowance shaft support surfaces 41a, 41b are provided. And 41c are semi-cylindrical non-tightening shaft bearing surfaces 42a, 42b and 4 that are slidably in contact with the peripheral surface 40 of the rack shaft 39 without tightening. each of which has a shaft bearing surface 43a, 43b and 43c made of c, and one semi-cylinder extending in the axial direction Y from one end surface 44a, 44b and 44c of the semi-cylindrical divided pieces 31a, 31b and 31c. Surfaces 45a, 45b and 45c, and one tapered surface 46a which extends from the end of the one semi-cylindrical surface 45a, 45b and 45c to one end in the axial direction Y of the shaft bearing surfaces 43a, 43b and 43c and which is gradually reduced in diameter. 46b and 46c, and the other semi-cylindrical surface 48a extending in the axial direction Y from the other end surfaces 47a, 47b and 47c of the semi-cylindrical divided pieces 31a, 31b and 31c (not shown but similar to the semi-cylindrical surface 48b), 48b and 48c and the other semi-cylindrical surfaces 48a, 48b and 48c extend from the ends of the shaft bearing surfaces 43a, 43b and 43c to the other end in the axial direction Y. The other tapered surface 49a which is reduced in diameter s (the same as not shown tapered surface 49b), has respectively a 49b and 49c.

  Semi-cylindrical surfaces 45a, 45b and 45c, semi-cylindrical surfaces 48a, 48b and 48c and tapered surfaces 46a, 46b and 46c and tapered surfaces of the inner peripheral surfaces 38a, 38b and 38c of the semi-cylindrical divided pieces 31a, 31b and 31c. By forming 49a, 49b and 49c, the rack shaft 39 can be easily mounted on the inner peripheral surfaces 38a, 38b and 38c from the tapered surfaces 46a, 46b and 46c or the tapered surfaces 49a, 49b and 49c side. Can be reduced.

  On each of the non-contact surfaces 37a, 37b, and 37c of the outer peripheral surfaces 33a, 33b, and 33c of the semi-cylindrical divided pieces 31a, 31b, and 31c, strip-shaped protrusions 51a, 51b, and 51c extending along the axial direction Y have a diameter. The belt-shaped protrusions 51a, 51b, and 51c that are integrally provided at positions corresponding to the fastening allowance shaft support surfaces 41a, 41b, and 41c in the direction and are surrounded by the non-contact surfaces 37a, 37b, and 37c, In the circumferential direction X, the pair of contact surfaces 36a, 36b and 36c are spaced apart from each other in the circumferential direction X with respect to each of the pair of contact surfaces 36a, 36b and 36c, and the pair of contact surfaces 36a, 36b and 36c are arranged in the circumferential direction X, and each of the outer peripheral surfaces 52a, 52b and 52c of the belt-like protrusions 51a, 51b and 51c is the gear case 3 The inner peripheral surface 35 so as not to contact the of, and facing to the peripheral surface 40 with a gap therebetween.

  Each of the belt-like protrusions 51a, 51b and 51c having radial outer peripheral surfaces 52a, 52b and 52c which do not contact the inner peripheral surface 35 of the gear case 34 is divided into a semi-cylindrical shape at the non-contact surfaces 37a, 37b and 37c. The radial rigidity of the pieces 31a, 31b and 31c is increased.

  Each of the thin connecting pieces 32a, 32b, and 32c includes bent portions 53a, 53b, and 53c that are bent radially outward at the center thereof, and has a V-shape when viewed from the axial direction Y. Yes.

  Instead of providing each of the thin connecting pieces 32a, 32b, and 32c with each of the bent portions 53a, 53b, and 53c that fold outward in the radial direction, as shown in FIG. Each of the bent portions 54a, 54b, and 54c is provided and has a V shape when viewed from the axial direction Y, and instead of the V shape, as shown in FIG. Each of the curved portions 55a, 55b, and 55c projecting outward is provided, and when it is U-shaped when viewed from the axial direction Y, it further projects radially inward at the center as shown in FIG. Each of the curved portions 56a, 56b, and 56c may be provided and may be U-shaped when viewed in the axial direction Y.

  By making the thin connecting pieces 32a, 32b, and 32c V-shaped or U-shaped when viewed from the axial direction Y, the synthetic resin sliding bearing 30 is expanded and contracted due to the thermal history due to the temperature rise in the gear case 34. When received, the expansion and contraction can be more effectively absorbed by the expansion and contraction of the thin connecting pieces 32a, 32b, and 32c in the circumferential direction X with radial overhang.

  The width (length) of each of the thin connecting pieces 32a, 32b and 32c in the axial direction Y is a pair of semi-cylindrical divided pieces 31a and 31b, 31b and 31c sandwiching the thin connecting pieces 32a, 32b and 32c, and The semi-cylindrical divided pieces 31a, 31b and 31c are formed so as to form slit grooves 57 at both ends in the axial direction Y of the thin-walled connecting pieces 32a, 32b and 32c in cooperation with the respective 31c and 31a. It is narrower than the width (length) of each axial direction Y.

  The thin connecting pieces 32a, 32b and 32c having such a width can absorb the expansion and contraction in the circumferential direction X of the synthetic resin sliding bearing 30 more effectively.

  According to the synthetic resin sliding bearing 30 described above, the rack shaft 39 has the non-contact surfaces 37a, 37b, and 37c that do not contact the inner peripheral surface 35 of the gear case 34 between the pair of contact surfaces 36a, 36b, and 36c. The shaft bearing surfaces 41a, 41b and 41c with tightening allowances arranged corresponding to the radial direction and arranged in the circumferential direction X have predetermined tightening allowances, and the contact surfaces 36a, 36b and 36 36c and non-clamping allowance shaft support surfaces 42a, 42b and 42c arranged in the circumferential direction X with the clamping allowance shaft support surfaces 41a, 41b and 41c in between. The non-contact surface 3 that is slidably supported in the axial direction Y and does not contact the inner peripheral surface 35 of the gear case 34 of the semi-cylindrical divided pieces 31a, 31b, and 31c. Band-shaped protrusions 51a, 51b, and 51c are integrally provided on a, 37b, and 37c corresponding to the tightening shaft support surfaces 41a, 41b, and 41c in the radial direction, and are formed on the inner peripheral surface 35 of the gear case 34. Since the radial rigidity of the non-contact surfaces 37a, 37b, and 37c that are not in contact is enhanced, the rack shaft 39 is unlikely to be bent during a steering operation or the like, and the rack shaft 39 and the synthetic resin sliding bearing 30 are not bent. In addition, even when the synthetic resin sliding bearing 30 is subjected to expansion or contraction due to a thermal history due to a temperature rise in the gear case 34, the expansion or contraction is semi-cylindrical. Since it is absorbed by the expansion and contraction in the circumferential direction X accompanied by the overhang in the radial direction of the thin connecting pieces 32a, 32b and 32c that connect the divided pieces 31a, 31b and 31c to each other in the circumferential direction X. The predetermined tightening allowance between the rack shaft 39 and the synthetic resin sliding bearing 30 is not lost due to the stress relaxation due to the thermal history, and the elastic supporting force of the rack shaft 39 is not reduced. No hitting sound is generated between the sliding bearing 30 made of resin.

  In the synthetic resin sliding bearing 30 described above, on the inner peripheral surfaces 38a, 38b and 38c of the semi-cylindrical divided pieces 31a, 31b and 31c, preferably as shown in FIG. A plurality of indents (dents) 58 may be formed on the tightening shaft support surfaces 41a, 41b and 41c, and the plurality of indents 58 plays a role of filling and holding a lubricant such as grease. The plurality of indents 58 filled with a lubricant such as grease allows the rack shaft 39 supported on the shaft support surfaces 43a, 43b and 43c to slide smoothly.

  Furthermore, in the above-described synthetic resin sliding bearing 30, as shown in FIGS. 10 and 11, the end surfaces 47a, 47b and 47c side (end surfaces 44a, 44b and 44c side) of the semi-cylindrical divided pieces 31a, 31b and 31c may be used. ) Non-contact surfaces 37a, 37b, and 37c may be integrally formed by projecting locking projections 59a, 59b, and 59c that fit into the inner peripheral surface 35 of the gear case 34 in the radial direction. .

  The locking projections 59a, 59b, and 59c are fitted into an engagement hole or an engagement groove (not shown) formed in the gear case 34, thereby entering the gear case 34 of the synthetic resin sliding bearing 30. Can be easily fixed while being fixed.

It is a front view which shows the preferable example of the synthetic resin sliding bearings of this invention. It is the II-II sectional view taken on the line of FIG. It is a top view of FIG. FIG. 2 is a cross-sectional view in which the synthetic resin sliding bearing of the embodiment shown in FIG. 1 is arranged between a rack shaft and a gear case in a rack and pinion type steering device. It is a partial enlarged front view which shows the preferable example of a thin connection piece. It is a partial enlarged front view which shows the other preferable example of a thin connection piece. It is a partial enlarged front view which shows the other preferable example of a thin connection piece. It is a partial enlarged front view which shows the other preferable example of a thin connection piece. It is sectional drawing which shows the other preferable example of the synthetic resin sliding bearings of this invention. It is a front view which shows the other preferable example of the synthetic resin sliding bearings of this invention. It is XI-XI sectional view taken on the line of FIG. It is explanatory drawing of a prior art example.

Explanation of symbols

30 Synthetic plastic sliding bearings 31a, 31b, 31c Semi-cylindrical divided pieces 32a, 32b, 32c Thin-walled connecting pieces 33a, 33b, 33c Outer peripheral surface 34 Gear cases 38a, 38b, 38c Inner peripheral surface 39 Rack shafts 43a, 43b, 43c Shaft bearing surface

Claims (9)

  A synthetic resin sliding bearing interposed between the rack shaft and the gear case to support the rack shaft movably in the gear case, and is divided into at least three semi-cylindrical sections arranged in the circumferential direction. Each semi-cylindrical piece is integrally provided with a piece and a thin connecting piece that is formed thinner than the semi-cylindrical divided piece. The outer peripheral surface of the segmented piece has a pair of contact surfaces that contact the inner peripheral surface of the gear case and a non-contact surface that does not contact the inner peripheral surface of the gear case. The inner peripheral surface is provided at a position corresponding to the non-contact surface in the radial direction and is a tightening shaft support surface that supports the rack shaft by slidingly contacting the peripheral surface of the rack shaft with a predetermined tightening allowance. And in the radial direction across the tightening shaft support surface in the circumferential direction The non-tightening shaft is provided at a position corresponding to the contact surface and is slidably in contact with the peripheral surface of the rack shaft without having a tightening allowance, and having a diameter larger than that of the tightening allowance shaft support surface. A non-contact surface of the outer peripheral surface of each semi-cylindrical divided piece has a belt-like protrusion extending along the axial direction in the radial direction and a bearing surface with a tightening allowance. Synthetic resin sliding bearings, which are integrally provided corresponding to the above.   The axial width of the at least one thin-walled connecting piece is formed with slits at both ends in the axial direction in cooperation with a pair of semi-cylindrical divided pieces that sandwich the at least one thin-walled connecting piece in the circumferential direction. The synthetic resin sliding bearing according to claim 1, which is narrower than the axial width of the semicylindrical divided piece.   The synthetic resin product according to claim 1 or 2, wherein at least one thin-walled connecting piece has a bent portion that is bent radially outward at a central portion thereof and has a V shape when viewed from the axial direction. Plain bearing.   The at least one thin connecting piece has a bent portion that is bent radially inward at a central portion thereof, and has a V shape when viewed from the axial direction. The synthetic resin sliding bearing described.   The at least one thin-walled connecting piece has a curved portion projecting radially outward at a central portion thereof, and has a U-shape when viewed from the axial direction. The synthetic resin sliding bearing described.   The at least one thin-walled connecting piece has a curved portion projecting radially inward at a central portion thereof and has a U-shape when viewed from the axial direction. The synthetic resin sliding bearing described.   The inner circumferential surface of each semi-cylindrical divided piece has one semi-cylindrical surface extending in the axial direction from one end face of the semi-cylindrical divided piece, and the axial direction of the shaft bearing surface from the end of the one semi-cylindrical face. One tapered surface extending to one end of the semi-cylindrical portion and gradually decreasing in diameter, the other semi-cylindrical surface extending in the axial direction from the other end surface of the semi-cylindrical divided piece, and a shaft bearing from the end of the other semi-cylindrical surface The synthetic resin sliding bearing according to any one of claims 1 to 6, further comprising: the other tapered surface which extends to the other end in the axial direction of the surface and gradually decreases in diameter.   The synthetic resin sliding bearing according to any one of claims 1 to 7, wherein a plurality of indents are formed on a shaft support surface of an inner peripheral surface of at least one semicylindrical divided piece.   The synthetic resin according to any one of claims 1 to 8, wherein a locking projection that fits to an inner peripheral surface of the gear case is provided on an outer peripheral surface of at least one semicylindrical divided piece. Plain bearing.

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