JP2013194777A - Method of manufacturing sintered bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method capable of molding a sintered bearing having a bearing surface on an inner periphery and having an outer peripheral surface insert-molded by resin on an outer periphery with high concentricity between the bearing surface and the outer peripheral surface, and superior in productivity.SOLUTION: A method of manufacturing a sintered bearing 1 includes a process of manufacturing a cylindrical sintered metal body 2 having a bearing surface 2a on an inner periphery, a process of arranging the sintered metal body 2 in a molding metal mold 10 having an inner mold part 15 and an outer mold part 14 by fitting the bearing surface 2a of the sintered metal body 2 to the inner mold part 15 and forming a cavity 13 between the outer periphery of the sintered metal body 2 and the outer mold part 14, and a process of molding a resin part 3 by injecting resin P into the cavity 12, and is characterized by finely adjusting a relative position of the inner mold part 15 and the outer mold part 14 in the radial direction of a molded article by an adjusting mechanism 16 arranged in the inner mold part 15 or the outer mold part 14.

Description

  The present invention relates to a method for manufacturing a sintered bearing.

  Conventionally, iron-based, copper-iron-based, and copper-based bearings have been widely used as sintered bearings. This type of sintered bearing is fitted and fixed in a housing made of a material made of molten metal such as brass or stainless steel, or a die-cast product made of zinc or aluminum. Many. In such a use form, particularly in use equipment that requires high accuracy, a high coaxiality between the radial bearing surface of the sintered bearing after fitting and fixing to the housing described above and the mounting surface of the housing attached to the use equipment. Degree is required. Therefore, it is necessary to add a finishing process to the mounting surface of the housing in order to increase accuracy, and an increase in cost is inevitable.

  On the other hand, in order to avoid deformation of the sintered bearing due to press-fitting into the inner circumference of the motor housing, a press-fit covering member in which resin is insert-molded on the outer circumference of the sintered bearing is disclosed (patent) Reference 1).

JP 2007-255515 A

  However, in Patent Document 1, when the sintered bearing is press-fitted into the inner periphery of the housing, the press-fitting covering member covering the outer periphery of the sintered bearing corresponds to the deviation of the roundness of the housing in the radial direction. It is designed to be transformed into Since this sintered bearing is premised on deformation of the press-fitting laying member, it does not consider the coaxiality between the bearing surface of the sintered bearing and the outer peripheral surface of the press-fitting laying member.

  When the resin is insert-molded into the sintered metal body, the clearance between the bearing surface and the inner mold part is indispensable in order to fit and arrange the sintered metal body as an insert part in the inner mold part. And if the production lot of the sintered metal body which is an insert part changes, since the bearing surface dimension formed in the inner periphery of the sintered metal body will inevitably change, a clearance changes for every production lot. On the other hand, in terms of equipment, insert molding in industrial production of this type of product uses a horizontal injection molding machine that is small in size and high in productivity, so that the arrangement of the mold is such that the axis of the bearing surface is horizontally arranged. Because of this situation, the coaxiality between the bearing center and the mold center varies, and the coaxiality between the bearing surface and the resin molding surface decreases. It turns out that there is a problem.

  In addition, it is conceivable that the entire bearing surface and the outer housing, including the inner peripheral bearing surface, are formed as a single unit with sintered metal. However, since the sintered metal has a complicated shape, the precision and durability of the molding die It was also found that it was not practical because it required additional processing such as machining and sealing as a finishing problem.

  In view of the conventional problems, the present invention can form a sintered bearing having a bearing surface on the inner periphery and an outer peripheral surface insert-molded with resin on the outer periphery with a high coaxiality between the bearing surface and the outer peripheral surface, and An object is to provide a production method with high productivity.

  As a result of various studies to achieve the above object, the present inventor can use a highly accurate simple cylindrical sintered metal body and finely adjust the inner mold and the outer mold of the insert molding in the radial direction. Together with the new idea of making it, the present invention was reached.

  As technical means for achieving the above-mentioned object, the present invention provides a process for producing a cylindrical sintered metal body having a bearing surface on the inner periphery, and a molding die having an inner mold part and an outer mold part. A step of fitting the bearing surface of the sintered metal body into the inner mold portion and forming a cavity between the outer periphery of the sintered metal body and the outer mold portion, and disposing the sintered metal body And a step of injecting resin into the cavity to form a resin portion, and the relative position between the inner mold portion and the outer mold portion by an adjustment mechanism provided in the inner mold portion or the outer mold portion. Is characterized by a method for manufacturing a sintered bearing in which the fine adjustment is made in the radial direction of the molded product. With such a configuration, the inner mold part and the outer mold part with which the bearing surface is fitted are finely adjusted relatively in the radial direction with reference to a highly accurate bearing surface of a simple cylindrical sintered metal body. Therefore, the high coaxiality of the resin-molded outer peripheral surface and the bearing surface can be ensured. Moreover, by using a simple cylindrical sintered metal body, the productivity is good and the manufacturing cost can be reduced.

  The structure provided with the shaping | molding surface which shape | molds the attachment surface formed in the outer periphery of the resin part in said outer mold part is preferable. A plurality of molding surfaces can be formed on the outer mold part. Thereby, high coaxiality between the bearing surface and the mounting surface can be easily obtained by injection molding, which is suitable for applications that require high accuracy.

  It is preferable to inject the above resin from a pin gate provided at the radial center of the molded product. As a result, the resin can flow evenly, the weld line can be eliminated, and further accuracy and strength can be obtained.

  The above adjustment mechanism is provided in the outer mold part, and in the fine adjustment, the inner mold part is fixed and the outer mold part is movable in the radial direction of the molded product, thereby efficiently arranging the configuration of the molding die. Can be configured. However, the present invention is not limited to this, and it is also possible to provide an adjustment mechanism in the inner mold part, make the inner mold part movable, and fix the outer mold part.

  According to the manufacturing method of the present invention, a sintered bearing having a bearing surface on the inner periphery and an outer peripheral surface insert-molded with resin on the outer periphery can be molded with high coaxiality between the bearing surface and the outer peripheral surface, and produced. Can be improved.

(A) A figure is a longitudinal cross-sectional view of the sintered bearing manufactured by the manufacturing method of the 1st Embodiment of this invention, (b) A figure is a cross-sectional view in the AA line of (a) figure It is. (A) A figure is a longitudinal cross-sectional view of the sintered metal body used for this embodiment, (b) A figure is a cross-sectional view in the BB line of (a) figure. It is a figure which shows the process of manufacturing a sintered metal body. (A) A figure is a cross-sectional view of a shaping die, (b) A figure is a partial longitudinal cross-sectional view of a shaping die. Both figures are views showing a process of arranging a sintered metal body in a molding die. (A) A figure is a cross-sectional view of a shaping die, (b) A figure is a partial longitudinal cross-sectional view of a shaping die. Both figures are diagrams showing a process of injection molding a resin. (A) A figure is a longitudinal cross-sectional view of the sintered bearing manufactured by the manufacturing method of the 2nd Embodiment of this invention, (b) figure is a cross-sectional view in CC line of (a) figure It is. (A) A figure is a cross-sectional view of a shaping die, (b) A figure is a partial longitudinal cross-sectional view of a shaping die.

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

  The manufacturing method of the sintered bearing which concerns on the 1st Embodiment of this invention is demonstrated based on FIGS. A sintered bearing based on this manufacturing method is shown in FIG. Fig.1 (a) is a longitudinal cross-sectional view of the sintered bearing 1, and FIG.1 (b) is a cross-sectional view in the AA line of Fig.1 (a). As shown in the figure, the sintered bearing 1 is composed of a sintered metal body 2 and a resin portion 3. The sintered metal body 2 is formed in a cylindrical shape having a radial bearing surface 2a on the inner periphery. The resin part 3 is insert-molded on the outer periphery of the sintered metal body 2, and the sintered metal body 2 and the resin part 3 are an integral part. A mounting surface 3a is formed on the outer periphery of the resin portion 3 during insert molding. The mounting portion 3a is fitted and incorporated in a housing or the like (not shown) of the device to be used, and a shaft (not shown) is inserted into the bearing surface 2a on the inner periphery and supported so as to be relatively rotatable. In the sintered bearing 1, the radial bearing surface 2a on the inner periphery and the mounting surface 3a on the outer periphery have high coaxiality by a manufacturing method described later. Therefore, this sintered bearing 1 is suitable for applications that require high rotational accuracy.

  Next, the manufacturing method of this embodiment is demonstrated based on FIGS. First, the process of manufacturing the metal sintered body 2 will be described. FIG. 2 shows a sintered metal body. Fig.2 (a) is a longitudinal cross-sectional view of a sintered metal body, FIG.2 (b) is a cross-sectional view in the BB line of Fig.2 (a). The sintered metal body 2 is formed by filling a raw material powder mixed with various powders into a mold, compressing this to form a green compact, and then sintering the green compact. In this embodiment, in order to finish the bearing surface 2a with high accuracy, the metal sintered body 2 has a simple cylindrical shape including an inner peripheral bearing surface 2a and an outer peripheral surface 2b.

  Specifically, the sintered metal body 2 is manufactured through a raw material powder preparation step S1, a compacting step S2, a sintering step S3, and a sizing step S4 as shown in FIG. Since each of these steps itself is the same as the case of manufacturing a general sintered bearing, only the characteristic part in the manufacturing method of this embodiment will be described.

  In the compacting step S2, as shown in FIG. 2, the sintered metal body 2 has a simple cylindrical shape composed of an inner peripheral bearing surface 2a and an outer peripheral surface 2b, so that the bearing surface 2a is compressed with high accuracy. Can be molded.

  The surface of the sintered metal body 2 that has undergone the sintering step S3 is shaped in the sizing step S4. In this step, the bearing surface 2a is compressed by sizing and the porous structure is densified, and the surface pressure between the shaft inserted into the bearing surface 2a after completion as a product can be suppressed. On the other hand, the outer peripheral surface 2b of the sintered metal body 2 suppresses the amount of compression during sizing. As a result, the porosity of the outer peripheral surface 2b is larger than that of the bearing surface 2a. Therefore, in the injection molding of the resin portion 3 (see FIG. 1), which will be described later, the porosity of the outer peripheral surface 2b is strongly Can be combined.

  An example of a method for producing a copper-based sintered metal body is shown as a specific example of the sintered metal body 2 produced in the above process. In the raw material powder preparation step S1, 96 to 97% by mass of bronze powder (mixed powder of copper-10% tin) and 3 to 4% by mass of graphite powder are prepared as the raw material powder. An agent (such as zinc stearate) was added in an amount of 0.5 to 0.8% by mass and mixed with a V-type mixer. Thereafter, the green compact was pressed into a green compact at a pressure in the range of 200 to 700 MPa in the compacting step S2, and the green compact was sintered in the reducing atmosphere in the range of 750 to 810 ° C. in the sintering step S3. . Thereafter, in the sizing step S4, sizing was finally performed at a predetermined pressure within a range of 200 to 700 MPa, and the dimensional accuracy was shaped.

  The process of insert molding resin on the outer periphery of the sintered metal body 2 manufactured by the above process will be described with reference to FIGS.

  FIG. 4 shows a process in which the sintered metal body is arranged in the molding die, and shows a state before the resin is injection molded. 4A is a cross-sectional view of the molding die, and FIG. 4B is a partial longitudinal sectional view of the molding die. In these drawings, a molding die used in the manufacturing method of the present embodiment is conceptually shown. As shown in FIG. 4B, the molding die 10 is guided by a fixed die 11 and, for example, a guide pin (not shown), and is movable in the axial direction (axial direction of the molded product) with respect to the fixed die 11. It is composed of a movable mold 12. In insert molding in industrial production of this type of product, a horizontal injection molding machine with a small size and good productivity is used, so that the molding die 10 is arranged with the axis of the bearing surface 2a disposed horizontally. The fixed mold 11 has a gate 11a communicating with the cavity 13, a molding surface 14a on the inner peripheral surface thereof as an outer wall surface of the cavity 13, and an outer mold part 14 movable in the radial direction, and a radial position of the outer mold part 14 And an adjusting mechanism 16 for adjusting. As the gate 11a, a known gate shape such as a point gate (including a multi-point gate), a ring gate, or a film gate can be adopted, and is appropriately selected according to the size / shape of the molded product and the injection material.

  The movable mold 12 includes an inner mold portion (core pin) 15 having an outer peripheral surface 15a. The bearing surface 2a of the sintered metal body 2 is fitted to the outer peripheral surface 15a of the inner mold portion 15 and arranged. The outer peripheral surface 2 a of the sintered metal body 2 constitutes the inner wall surface of the cavity 13, and the shoulder portion 15 b of the inner mold portion 15 constitutes the end wall surface of the cavity 13. In the present embodiment, the inner mold portion 15 is a fixed mold portion.

  As shown in FIG. 4A, a molding surface 14 a for molding the mounting surface 3 a of the resin portion 3 is formed on the inner periphery of the outer mold portion 14. The outer mold part 14 and the adjustment mechanism 16 are accommodated in an accommodating part 17 provided in the fixed mold 11. The adjustment mechanism 16 is disposed at a position opposite to the outer wall surface 14b of the outer mold part 14 having a rectangular cross section so as to position the outer mold part 14 in the first direction (x-axis direction in the drawing). In order to position the first pressure member 18 and the support member 19 in the second direction (in the drawing, the y-axis direction) of the outer mold part 14, the outer wall surface 14 b of the outer mold part 14 is the same as described above. The second pressurizing member 20 and the support member 21 are arranged at positions facing each other at 180 °. The pressure members 18 and 20 and the support members 19 and 21 are connected to a feed means 22 that can be precisely fed, such as an adjusting screw. Position adjustment, that is, positioning of the outer mold portion 14 in the radial direction is performed.

  In the molding die 10 used in the present embodiment, the outer surface of the first pressure member 18 and the inner wall surface of the housing portion 17 with which the first pressure member 18 abuts are arranged on the y axis so as to move the outer mold portion 14 in the x axis direction. Is inclined by an angle α, and a first tapered surface A is provided to guide the pressure member 18 in the x-axis direction. Therefore, for example, when the first pressure member 18 is moved downward in the figure by L, the first pressure member 18 is simultaneously advanced by L × tan α in the x-axis direction. That is, in this case, the feed amount (the amount of movement of the outer mold part 14) applied to the outer mold part 14 by the first pressure member 18 is L × tanα in the x-axis direction. If the inclination angle α is set to less than 45 °, fine adjustment can be made with the amount of movement of the outer mold portion 14 in the x-axis direction being L × tan α.

  Similarly, the outer surface of the second pressure member 20 and the inner wall surface of the accommodating portion 17 with which the second pressing member 20 abuts are inclined by an angle α with respect to the x axis in order to move the outer mold portion 14 in the y axis direction. A second tapered surface B that guides the second pressure member 20 in the y-axis direction is provided. Therefore, in the same manner as described above, it is possible to finely adjust the amount of movement of the outer mold portion 14 in the y-axis direction to L × tan α.

  In the molding die 10 having the above configuration, the sintered bearing 1 can be molded, for example, in the following manner. First, in a state where the molding die 10 having the above configuration is set in the injection molding machine, the position of the outer mold portion 14 is adjusted by the adjusting mechanism 16, and the outer wall surface 14 b of the outer mold portion 14 is restrained by the two pairs of adjusting mechanisms 16. To do. Then, in the state shown in FIG. 4, that is, in a state where the bearing surface 2 a of the sintered metal body 2 is fitted to the outer peripheral surface 15 a of the inner mold part 15, the movable mold 12 is advanced and matched with the fixed mold 11. As a result, the bearing surface 2 a of the sintered metal body 2 is fitted to the inner mold part 15, and the cavity 13 is formed between the outer periphery of the sintered metal body 2 and the outer mold part 11.

  Thereafter, trial molding is performed in a state where the temperature of the molding die 10 is stable. FIG. 5 shows a process of injection molding a resin on the molding die 10. As in FIG. 4, FIG. 5 (a) is a cross-sectional view of the molding die, and FIG. 5 (b) is a partial longitudinal sectional view of the molding die. At the time of molding, molten resin P injected from a nozzle of an injection molding machine (not shown) enters the gate 11a through the runner and is filled into the cavity 13 from the gate 11a. The molten resin P filled in the cavity 13 is cooled and solidified, the movable mold 12 is moved to open the mold, and a molded product (fired product) in which the sintered metal body 2 and the resin portion 3 shown in FIG. Take out the bearing 1).

  Subsequently, the coaxiality of the bearing surface 2a of the taken-out sintered bearing 1 and the mounting surface 3a (see FIG. 1) of the resin portion 3 is measured. Based on this measurement result, the pressure members 18 and 20 of the adjustment mechanism 16 and the feeding means 22 connected to the support members 19 and 21 are respectively operated to adjust the radial position of the outer mold part 14, and the coaxiality Correct the madness. This adjustment operation may be performed a plurality of times as necessary. After the adjustment work is completed, the main molding is performed. Also in this main forming, the movable mold 12 is advanced to the fixed mold 11 in the state shown in FIG. 4, that is, the bearing surface 2 a of the sintered metal body 2 is fitted to the outer peripheral surface 15 a of the inner mold portion 15. Match the mold. In the present specification, this process in the main molding is performed by fitting the bearing surface 2a of the sintered metal body 2 into the inner mold portion 15 in the molding die 10 and the outer periphery of the sintered metal body 2 and the outer mold portion 11. It is called a process of forming the cavity 13 between the two and placing the sintered metal body 2.

  Once the adjustment work of the outer mold portion 14 described above is completed, the main forming for one production lot of the sintered metal body 2 is performed in this state. The state of the main molding is the same as the state shown in FIG. 5, and the molten resin P injected from the nozzle of the injection molding machine enters the gate 11a through the runner and is filled into the cavity 13 from the gate 11a. The molten resin P filled in the cavity 13 is cooled and solidified, the movable mold 12 is moved and the mold is opened, and the sintered metal body 2 and the resin portion 3 shown in FIG. A molded product (sintered bearing 1) is obtained. In this way, since the main forming can be continuously performed for the production lot, the bearing surface and the outer peripheral surface can be formed with high coaxiality, and the productivity can be improved.

  When the production lot of the sintered metal body 2 that is an insert part changes, a change in the size of the bearing surface formed on the inner periphery of the sintered metal body 2 inevitably occurs, and the outer peripheral surface of the bearing surface 2a and the inner mold portion 15 The clearance with 15a will change. Therefore, it is preferable to perform the above-described trial molding and adjustment of the outer mold portion 14 before the main molding for each production lot. Thereby, even if a manufacturing lot changes, the radial bearing surface 2a of an inner periphery and the attachment surface 3a of an outer periphery can maintain high coaxiality. However, if a change in the bearing surface dimension of the sintered metal body 2 that is inevitably generated is allowed in a very small amount, trial molding for each production lot and adjustment of the outer mold part 14 can be omitted.

  Further, the outer peripheral surface 2b of the sintered metal body 2 suppresses the amount of compression at the time of the sizing process described above, and the outer peripheral surface 2b is larger in the porosity than the bearing surface 2a. 3 can be firmly bonded by the anchor effect.

  In the present embodiment, the support members 19 and 21 are operated by the feeding means 22 to adjust the position. However, the support members 19 and 21 are elastically supported in the forward and backward directions. Thus, the position adjustment of the support members 19 and 21 can be omitted.

  The molten resin P to be injected may be either an amorphous resin or a crystalline resin as a base resin, and these can be appropriately selected according to the characteristics required for the molded product. As the amorphous resin, polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), polyetherimide (PEI) and the like can be used, and as the crystalline resin, a liquid crystal polymer can be used. (LCP), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and the like can be used. These are merely examples, and the usable base resins are not limited. These base resins may be mixed with one or more of various fillers such as a reinforcing material (in any form such as a fiber or powder), a lubricant, and a conductive material as necessary.

  As described above, the outer mold part 14 is adjusted and moved in the radial direction by the adjusting mechanism 16 according to the deviation of the coaxiality, and the radial position with respect to the inner mold part 15 is adjusted. The degree can be made highly accurate. In particular, in the present embodiment, the first and second pressure members 18 and 20 that pressurize the outer mold portion 14 in the biaxial direction are provided with tapered surfaces, respectively. Accordingly, as long as the taper angle of the taper surface is set to an appropriate value, the amount of movement of the outer mold portion 14 can be reduced, whereby the inner peripheral bearing surface 2a and the outer peripheral mounting surface 3a are coaxial. Can be further increased.

  Although it depends on the size of the molded product, the required degree of coaxiality, and the like, if the inclination angle α of the tapered surfaces A and B is too large, the first and second pressure members 18 when the feeding means 16 is advanced and retracted. , 20 is increased, and it becomes difficult to correct the deviation of the coaxiality with a predetermined accuracy. On the other hand, if the inclination angle α is too small, the forward and backward strokes of the first and second pressure members 18 and 20 necessary for obtaining the amount of movement of the outer mold part 14 become large, the mold becomes large and its structure. Is complicated. From the above, the inclination angle α of the tapered surfaces A and B is preferably set to 1 ° or more and 10 ° or less, more preferably 2 ° or more and 5 ° or less. This is to eliminate the disadvantages of increasing and decreasing the inclination angle α of the tapered surfaces A and B in a well-balanced manner.

  In the above description, the configuration in which the first tapered surface A and the second tapered surface B are provided on both the pressure members 18 and 20 and the accommodating portion 17 has been described. However, the first tapered surface A and the second tapered surface A are provided. The taper surface B is provided only on the pressure members 18 and 20 and the housing portion 17 is provided with a stepped portion, or the first taper surface A and the second taper surface B are provided only on the housing portion 17 and pressurize. The corners of the members 18 and 20 can be slid. In the present embodiment, the inclination angles of the first taper surface A and the second taper surface B are both α, but the inclination angles of the respective taper surfaces can be different from each other.

  In the molding die 10 used in the present embodiment, the adjustment mechanism 16 includes first and second pressure members 18 and 20 having tapered surfaces A and B formed to press the outer mold portion 14 in the biaxial direction. However, the present invention is not limited to this. For example, a configuration in which precision feeding means such as an adjusting screw is directly connected to the outer mold portion 14 may be employed.

  In the above description, the configuration in which the outer mold portion 3 is adjusted and moved in the radial direction has been described. However, the outer mold portion 3 may be fixed and the inner mold portion 4 may be adjusted and moved in the radial direction.

Next, the manufacturing method which concerns on the 2nd Embodiment of this invention is demonstrated based on FIG. 6 and FIG. A sintered bearing 1 manufactured by the manufacturing method of the present embodiment is shown in FIG. Fig.6 (a) is a longitudinal cross-sectional view of the sintered bearing 1, and FIG.6 (b) is a cross-sectional view in CC line of Fig.6 (a).
In this sintered bearing 1, the structure of the resin part 3 is different from the sintered bearing 1 manufactured by the manufacturing method of the first embodiment. In FIG. 6 and FIG. 7, portions having the same functions as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIGS. 6A and 6B, the resin portion 3 of the sintered bearing 1 has a stepped shape in which the outer periphery is composed of a plurality of mounting surfaces, a large-diameter mounting surface 3a and a small-diameter mounting surface 3b. It has become. The resin portion 3 has a bottomed shape having a bottom portion 3d and is sealed on one side, and a cylindrical recess 3c is formed on the radially inner side of the small-diameter mounting surface 3b. In the case of this sintered bearing 1, the small-diameter mounting surface 3b is not fixed to the housing of the equipment used, but is configured to be slidably fitted to a rotating component such as an idler gear. Thus, in this specification, the attachment surface is a concept including not only a surface fixed to the mating member but also a surface that moves relative to the mating member. Since other configurations are the same as those of the sintered bearing 1 manufactured in the first embodiment, a duplicate description is omitted.

  Next, the injection molding process of the resin part of this embodiment will be described with reference to FIG. Fig.7 (a) is a cross-sectional view of the molding die of FIG.7 (b), FIG.7 (b) is a partial longitudinal cross-sectional view of a molding die. FIG. 7A is a cross-sectional view at the axial center of the sintered metal body, and therefore this figure is the same as FIG. 5A of the first embodiment. FIG. 7B is different from FIG. 5B in the shapes of the fixed mold and the outer mold among the molding dies. Formed on the inner periphery of the outer mold portion 14 'are a molding surface 14'a for molding the large-diameter mounting surface 3a of the resin portion 3 and a 14'c for molding the small-diameter mounting surface 3b. The fixed mold 11 ′ is formed with a cylindrical portion 11 ′ b for molding the concave portion 3 c of the resin portion 3, and a pin gate 11 ′ a is provided at the radial center of the cylindrical portion 11 ′ b. The movable mold 12 and the inner mold portion 15 are the same as the molding mold of the first embodiment.

  Also in the injection molding process of the resin portion of the manufacturing method of the present embodiment, as described in the first embodiment, the above-described trial molding and the position adjustment of the outer mold portion 14 are performed before the main molding. When the production lot changes, trial molding and position adjustment of the outer mold part 14 can be performed to maintain the inner peripheral radial bearing surface 2a and the outer peripheral mounting surfaces 3a, 3b at high coaxiality.

  Further, in the injection molding process of the resin portion of the manufacturing method of the present embodiment, the resin is applied by the so-called center gate method in which the pin gate 11′a is provided in the center portion in the radial direction of the cylindrical portion 11′b of the fixed mold 11 ′. Since it is injection-molded, even if the resin part 3 has a plurality of mounting surfaces 3a and 3b, the resin can flow evenly and the weld line can be eliminated, and further accuracy and strength can be obtained. Can do. Other configurations, operations, and the like including the manufacturing process of the sintered metal body 2 are the same as those in the first embodiment, and thus redundant description is omitted.

  As described in the above embodiments, in the method for manufacturing a sintered bearing according to the present invention, a sintered bearing having a bearing surface on the inner periphery and an outer peripheral surface insert-molded with resin on the outer periphery is used. The surface can be molded with a high degree of coaxiality, and productivity can be improved.

  In the embodiment described above, the resin portion 3 of the sintered bearing 1 to be manufactured has a circular cross section. However, the resin portion 3 is not limited to this, and the non-circular cross section, for example, a polygonal shape or a flange shape having mounting holes. However, it can be suitably implemented.

  Furthermore, the molding die can be configured to perform not only radial positioning but also axial positioning.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Sintered bearing 2 Sintered metal body 2a Bearing surface 2b Outer peripheral surface 3 Resin part 3a Mounting surface 3b Mounting surface 10 Molding die 11 Fixed mold 11a Gate 12 Movable mold 13 Cavity 14 Outer mold part 14a Molding surface 14c Molding surface 15 Inside Mold part 15a Outer peripheral surface P Molten resin

Claims (5)

  A step of manufacturing a cylindrical sintered metal body having a bearing surface on the inner periphery, and a molding die having an inner mold portion and an outer mold portion, and the bearing surface of the sintered metal body as the inner mold portion. And a step of forming a cavity between the outer periphery of the sintered metal body and the outer mold portion and disposing the sintered metal body; and a step of injecting a resin into the cavity to mold the resin portion; The relative position between the inner mold part and the outer mold part is finely adjusted in the radial direction of the molded product by an adjustment mechanism provided in the inner mold part or the outer mold part. Manufacturing method of sintered bearing.   The method for manufacturing a sintered bearing according to claim 1, wherein the outer mold part includes a molding surface that molds a mounting surface formed on an outer periphery of the resin part.   The method for manufacturing a sintered bearing according to claim 1, wherein a plurality of the molding surfaces are formed on the outer mold part.   The method for manufacturing a sintered bearing according to any one of claims 1 to 3, wherein the resin is injected from a pin gate provided at a central portion in a radial direction of the molded product.   The adjustment mechanism is provided in the outer mold part, and the inner mold part is fixed and the outer mold part is movable in a radial direction of a molded product during the fine adjustment. 5. A method for manufacturing a sintered bearing according to claim 4.

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