JP2009041717A - Bearing device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device capable of surely fixing a bearing to a bearing retaining hole of a housing even in the case that the bearing is composed of a ferrous metal and its manufacturing method. <P>SOLUTION: In the bearing device 1, the housing 3 is composed of a ferrous material and the bearing 2 consists of a sintered body of copper-coated iron powder. Thus, the bearing 2 and the housing 3 can be fixed by diffused junction using a bonding material 4 composed of tin, tin alloy, silver or silver alloy and the bearing 2 and the housing 3 can be fixed with excellent strength by the fixing method. A sizing process is conducted for an inner circumferential surface of the bearing 2 while the bearing 2 and the housing 3 are fixed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing device in which a bearing is fixed to a bearing holding hole of a housing and a manufacturing method thereof.

In motor equipment and other equipment, various types of bearing devices are used for supporting a rotating shaft, and the bearing devices have a structure in which a bearing is fixed to a bearing holding hole of a housing. In order to securely fix the bearing in the bearing holding hole of the housing, the bearing is formed of copper-based metal, while the housing is formed of iron-based metal, and the bearing and the housing are plated on the inner peripheral surface of the bearing holding hole. It has been proposed to join the bearing and the housing with a brazing material such as tin, lead, zinc, silver, phosphorus, etc. (see Patent Document 1).
JP 2000-186714 A

  However, when the bearing is made of a copper-based metal, it is easy to braze, but the wear resistance performance on the inner peripheral surface of the shaft hole is low, so the above configuration can be applied only to the hydrodynamic bearing device. There is a problem.

  In view of the above problems, an object of the present invention is to provide a bearing device that can securely fix a bearing to a bearing holding hole of a housing and a method for manufacturing the same even when the bearing is made of an iron-based metal. It is in.

  In order to solve the above problems, the present invention includes a bearing having a shaft hole formed in the axial direction and a housing having a bearing holding hole into which the bearing is inserted, and the outer peripheral surface of the bearing and the bearing holding In the bearing device in which the inner peripheral surface of the hole is fixed, the bearing is made of a sintered body of copper-coated iron powder, the housing is made of an iron-based metal, and the bearing and the housing are made of the bearing. It is fixed by diffusion bonding using a bonding material made of tin, tin alloy, silver, or silver alloy between the outer peripheral surface and the inner peripheral surface of the bearing holding hole.

  The present invention includes a bearing having a shaft hole formed in the axial direction and a housing having a bearing holding hole into which the bearing is inserted, and the outer peripheral surface of the bearing and the inner peripheral surface of the bearing holding hole are In the manufacturing method of the fixed bearing device, the bearing is formed by sintering copper compacted iron powder against a green compact, while the housing is made of an iron-based metal, and the housing In the state where the bearing is fixed inside, a bonding material layer forming step of forming a bonding material layer made of tin, tin alloy, silver, or silver alloy on the inner peripheral surface of the bearing holding hole of the housing And incorporating the bearing into the bearing holding hole of the housing; heating the bonding material and fixing the outer peripheral surface of the bearing and the inner peripheral surface of the bearing holding hole by diffusion bonding of the bonding material Heating And extent, and performing.

  In the present invention, “copper-coated iron powder” means that the iron powder is covered with copper, and the iron powder is covered with a copper-based material such as bronze. In addition, “diffusion bonding” is a method in which a base material is brought into close contact, heated under a temperature condition equal to or lower than the melting point of the base material, and bonded using diffusion of atoms generated between bonding surfaces. And liquid phase diffusion bonding and eutectic bonding. Solid phase diffusion bonding is a method in which the bonding surfaces are bonded in a solid state, and liquid phase diffusion bonding is performed by temporarily melting and solubilizing the metal bonding material between the bonding surfaces and then using diffusion. This is a method of solidifying and joining. Eutectic bonding is a kind of liquid phase diffusion bonding and is a bonding method that utilizes a eutectic reaction for liquefaction.

  In the present invention, since the bearing is made of a sintered body of copper-coated iron powder and is formed of an iron-based metal, the wear resistance performance is good even when used as a sintered oil-impregnated bearing. Moreover, although the bearing is formed with the iron-type metal, it consists of a sintered compact of copper covering iron powder also in an iron-type metal. For this reason, since most of the surface of the iron powder is covered with copper in the bearing, the bearing and the housing are fixed by diffusion bonding using a bonding material made of tin, tin alloy, silver, or silver alloy. According to such a fixing method, the bearing and the housing can be fixed with high strength. Furthermore, since the sintered bearing is diffusion-bonded, the bonding material enters the pores of the sintered body and exhibits an anchor effect, so that there is an advantage that the bonding strength is high.

  In the present invention, a configuration in which only a part of the outer peripheral surface of the bearing in the axial direction is in contact with the inner peripheral surface of the bearing holding hole can be adopted, and such a configuration is adopted. Even in this case, according to the present invention, the bearing can be securely fixed to the bearing holding hole of the housing. The bearing device having such a configuration is manufactured by performing the heating step in the bearing assembling step so that only a part of the outer peripheral surface of the bearing in the axial direction is in contact with the inner peripheral surface of the bearing holding hole. The

  In the present invention, among the inner peripheral surfaces of the bearing holding hole, a configuration in which only a part in the axial direction is fixed to the outer peripheral surface in a state of being in contact with the outer peripheral surface of the bearing can be adopted, and such a configuration is adopted. However, according to this invention, a bearing can be reliably fixed to the bearing holding hole of a housing. The bearing device having such a configuration is manufactured by performing the heating step in the bearing assembling step in a state where only a part of the inner peripheral surface of the bearing holding hole is in contact with the outer peripheral surface of the bearing. The

  In the present invention, it is preferable that sizing is performed on at least a portion of the inner peripheral surface of the shaft hole that is located on the radially inner side of the fixing portion between the housing and the bearing. That is, in the method for manufacturing a bearing device to which the present invention is applied, it is preferable to perform a sizing process for sizing the inner peripheral surface of the shaft hole after the heating process. With this configuration, since the sizing is performed with the bearing fixed to the housing, for example, when the inner peripheral surface of the bearing is deformed during the bearing assembly process, or the shaft core is fixed with the bearing fixed to the housing. Even when it is tilted, such a problem can be completely solved.

  In the present invention, before the bearing assembling step, the green compact is sintered, and in the bearing assembling step, a method of incorporating the sintered bearing into the bearing holding hole of the housing is adopted. be able to.

  In the method for manufacturing a bearing device to which the present invention is applied, in the bonding material layer forming step, the bonding material layer is formed of silver, and in the bearing incorporation step, the green compact is in a state of the green compact before sintering. It is preferable that a bearing is incorporated in the bearing holding hole of the housing, and the green compact is sintered by heating in the heating step. If comprised in this way, the number of manufacturing processes can be reduced.

  In the present invention, since the bearing is made of a sintered body of copper-coated iron powder and is formed of an iron-based metal, the wear resistance performance is good even when used as a sintered oil-impregnated bearing. Moreover, although the bearing is formed with the iron-type metal, it consists of a sintered compact of copper covering iron powder also in an iron-type metal. For this reason, since most of the surface of the iron powder is covered with copper in the bearing, the bearing and the housing are fixed by diffusion bonding using a bonding material made of tin, tin alloy, silver, or silver alloy. According to such a fixing method, the bearing and the housing can be fixed with high strength.

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

[Embodiment 1]
(overall structure)
1A and 1B are a cross-sectional view of a bearing device according to Embodiment 1 of the present invention and a cross-sectional view of a state in which a rotating shaft is supported by the bearing device.

  As shown in FIGS. 1 (a) and 1 (b), a bearing device 1 according to the present embodiment is a sintered oil impregnated radial bearing device that rotatably supports a rotating shaft 10, and is a shaft that penetrates in the axial direction L. It has a cylindrical bearing 2 in which a hole 20 is formed, and a cylindrical housing 3 having a bearing holding hole 30 into which the bearing 2 is inserted. The outer peripheral surface 21 of the bearing 2 and the inner peripheral surface 35 of the bearing holding hole 30 are a bonding material 4 made of tin, tin alloy, silver, or silver alloy between the outer peripheral surface 21 of the bearing 2 and the bearing holding hole 30. It is fixed by diffusion bonding using.

  The housing 3 is made of a ferrous metal including SUS and the like, and is made of a pressed product. The housing 3 includes a small-diameter portion 31 to which the outer peripheral surface 21 of the bearing 2 is fixed, a large-diameter portion 32 adjacent to the small-diameter portion 31 in the axial direction L, and radially outward from the opening edge of the large-diameter portion 32. An annular flange portion 33 is provided, and only the inner peripheral surface 35 of the small diameter portion 31 is fixed to the outer peripheral surface 21 of the bearing 2 in the bearing holding hole 30. The housing 3 may be a ferrous metal cutting product.

  The bearing 2 is made of a sintered body obtained by sintering a green compact of copper-coated iron powder. Here, only a part of the bearing 2 in the axial direction L is inserted into the bearing holding hole 30 of the housing 3, and only a part of the outer peripheral surface 21 of the bearing 2 in the axial direction L of the bearing holding hole 30. The inner peripheral surface 35 is fixed in contact with the inner peripheral surface 35.

  Of the outer peripheral surface 21 of the bearing 2, at least a portion located radially inward with respect to a fixing portion between the housing 3 and the bearing 2 is intended to improve the surface state of the sintered body or correct the dimensions. Sizing (light cold press) is applied. The bearing 2 is impregnated with oil, and the bearing 2 is configured as a sintered oil-impregnated bearing.

(Production method)
Hereinafter, the configuration of the bearing device 1 of the present embodiment will be described in detail with reference to FIG. 2 while describing the method for manufacturing the bearing device 1 of the present embodiment. FIG. 2 and FIG. 3 are explanatory views showing the cooling process and the sizing process in the manufacturing process of the bearing device 1 of the present embodiment.

  In order to manufacture the bearing device 1 of this embodiment, first, as shown in FIG. 2 (a), after the copper-coated iron powder is molded in a mold to obtain the green compact 29, the green compact is obtained. 29 is heated to obtain a cylindrical bearing 2 made of a sintered body.

The powder raw material used here is, for example, the following materials (formulation example 1)
40% copper-plated iron powder (copper-coated iron powder) 98 parts by weight Atomized tin powder 2 parts by weight Natural graphite (graphite) 1 part by weight Zinc stearate 1 part by weight (Formulation Example 2)
40% copper-plated iron powder (copper-coated iron powder) 80 parts by weight Premixed bronze powder (10% by weight tin) 20 parts by weight Natural graphite (graphite) 1 part by weight Zinc stearate 1 part by weight (Formulation Example 3)
30% copper-plated iron powder (copper-coated iron powder) 98 parts by weight Atomized tin powder 1.98% by weight
Natural graphite (graphite) 1 part by weight Zinc stearate 1 part by weight (Formulation Example 4)
30% copper-plated iron powder (copper-coated iron powder) 70 parts by weight Premixed bronze powder (10% by weight tin) 30 parts by weight Natural graphite (graphite) 1 part by weight Zinc stearate 1 part by weight in an ammonia decomposition gas atmosphere The green compact 29 is sintered at a temperature of 750 to 850 ° C.

  On the other hand, as shown in FIG. 2C, after the cylindrical housing 3 is obtained by pressing the ferrous metal, in the bonding material layer forming step, as shown in FIG. A layer of the bonding material 4 made of tin, tin alloy, silver, or silver alloy is formed on the inner peripheral surface of the bearing holding hole 30. In this embodiment, since the layer of the bonding material 4 is formed by plating, the layer of the bonding material 4 is formed on all of the inner peripheral surface 35 and the outer peripheral surface of the housing 30. Here, the layer of the bonding material 4 is set to a thickness of, for example, about 3 to 5 μm from the viewpoint of securing bonding strength and plating cost.

  Next, as shown in FIG. 2 (e), the bearing 2 is assembled into the bearing holding hole 30 of the housing 3 by light press-fitting in the bearing assembling step. Here, “light press-fitting” refers to press-fitting with a force that does not change the inner diameter of the bearing 2 when press-fitted, or even when the inner diameter of the bearing 2 changes when press-fitted. This means press-fitting with a force that generates only a change in the range in which the inner diameter can be corrected.

  Next, as shown in FIG. 2 (f), in the heating step, the temperature is equal to or lower than the temperature at which the material constituting the bearing 2 and the housing 3 is melted, and is equal to or higher than the temperature at which the bonding material 4 is melted. The bonding material 4, the bearing 2, and the housing 3 are heated, and the outer peripheral surface 21 of the bearing 2 and the inner peripheral surface 35 of the small diameter portion 31 of the bearing holding hole 30 are fixed by liquid phase diffusion bonding of the bonding material 4.

  Thereafter, a sizing process described below with reference to FIGS. 3 (a) to 3 (d) is performed. Each of FIGS. 3A to 3D is an exploded view of the sizing device, an explanatory diagram showing the state of the sizing process, an enlarged cross-sectional view near the portion where the bearing device is accommodated in the sizing device, and after the sizing process, It is explanatory drawing which shows a mode that a bearing apparatus is taken out.

  In this embodiment, a sizing device 50 shown in FIGS. 3A, 3B, and 3C is used in the sizing process. The sizing device 50 includes a first fixing jig 51 and a second fixing jig 52 that hold the bearing device 1 from above and below. The first fixing jig 51 is formed with a stepped recess 511 corresponding to the outer shape of the bearing device 1 and a through hole 512 penetrating in the axial direction L at the bottom of the recess 511. Is equal to the outer diameter of the bearing 2 protruding downward from the housing 3 in the bearing device 1. The second fixing jig 52 uses the large-diameter portion 32 and the flange portion 33 (see FIG. 1) of the housing 3 of the bearing device 1 held in the recess 511 of the first fixing jig 51 for the first fixing. A cylindrical body in which a cylindrical protrusion 521 is formed on the lower end surface so as to be sandwiched between the jig 51 and the cylindrical body is formed with a guide hole 522 in the axial direction L. Here, the inner diameter dimension of the guide hole 522 of the second fixing jig 52 is substantially equal to the inner diameter dimension of the shaft hole 20 formed in the bearing 2 of the bearing device 1.

  The sizing device 50 includes a sizing bar 53 (movable member) inserted into the shaft hole 20 of the bearing 2 and a guide member 54 having a through hole 541 into which the sizing bar 53 is fitted. The outer diameter of the sizing bar 53 is substantially equal to the inner diameter of the shaft hole 20 formed in the bearing 2 of the bearing device 1 and the guide hole 522 formed in the second fixing jig 52.

  In order to perform sizing on the inner peripheral surface 21 of the bearing 2 of the bearing device 1 using the sizing device 50 configured as described above, as shown in FIGS. 3B and 3C, the first fixing jig is used. After mounting the bearing device 1 in the recess 511 of the 51, the bearing device 1 is pressed and fixed to the first fixing jig 51 by the second fixing jig 52. In this state, the through hole 512 formed in the first fixing jig 51, the shaft hole 20 of the bearing 2, and the guide hole 522 of the second fixing jig 52 communicate with each other.

  At this time, the outer side in the radial direction of the portion of the bearing 2 that is sized for the shaft hole 20 is held by the first fixing jig 51 and the second fixing jig 52. In this embodiment, since the sizing is performed on the entire axial direction L of the shaft hole 20, the entire outer peripheral surface of the bearing 2 is directly or by the first fixing jig 51 and the second fixing jig 52. It is assumed that it is held through Further, in the housing 3, a portion located on the outer side in the radial direction of the fixing portion (the small diameter portion 31 of the housing 3) between the housing 3 and the bearing 2 is held by the first fixing jig 51.

  Next, with the sizing bar 53 passed through the through hole 541 of the guide member 54, the upper end portion of the guide member 54 is inserted into the through hole 512 of the first fixing jig 51, and the upper end surface of the guide member 54 is The bearing 2 is brought into contact with the lower end surface.

  Next, while rotating the sizing bar 53 around the axis, the sizing bar 53 is reciprocated in the axial direction L, so that the outer peripheral surface of the sizing bar 53 improves the surface condition of the inner peripheral surface of the shaft hole 20 and the shaft hole 20. Perform sizing for the purpose of correcting the dimensions. Here, for sizing, the sizing bar 53 is rotated around the axis, but a method of reciprocating without rotating the sizing bar 53 or a method of reciprocating while rotating the sizing bar 53 around the axis is adopted. May be.

  After the sizing process is completed, as shown in FIG. 3D, the second fixing jig 52 is moved upward, the guide member 54 is moved upward, and the bearing device 1 is fixed first. The bearing device 1 is recovered by pushing out from the recess 511 of the jig 51 for use.

  After performing the sizing process on the bearing device 1 in this manner, the bearing device 1 is completed when the bearing 2 is impregnated with lubricating oil.

(Main effects of this form)
As described above, in the bearing device 1 of the present embodiment, the bearing 2 is made of a sintered body of copper-coated iron powder and is formed of an iron-based metal, so even when used as the sintered oil-impregnated bearing 2, Good wear resistance. Moreover, although the bearing 2 is formed with the iron-type metal, it consists of a sintered compact of copper covering iron powder also in an iron-type metal. For this reason, in the bearing 2, since most of the surface of the iron powder is coated with copper, the bearing 2 and the housing are formed by diffusion bonding using the bonding material 4 made of tin, tin alloy, silver, or silver alloy. 3 can be fixed, and according to this fixing method, the bearing 2 and the housing 3 can be fixed with high strength. Therefore, there is an advantage that the sizing process can be performed while the bearing 2 is fixed to the housing 3. Further, since the bearing 2 which is a sintered body is diffusion-bonded, the bonding material enters the pores of the sintered body and exhibits an anchor effect, so there is an advantage that the bonding strength is high.

  In this embodiment, only a part of the outer circumferential surface 21 of the bearing 2 in the axial direction L is fixed to the inner circumferential surface 35 of the bearing holding hole 30. Further, only a part of the inner circumferential surface 35 of the bearing holding hole 30 of the housing 3 in the axial direction L is fixed to the outer circumferential surface 21 of the bearing 2. For this reason, although the length dimension of the axial direction L of the adhering part of the bearing 2 and the housing 3 is short, in the bearing apparatus 1 of this embodiment, the bearing 2 and the housing 3 are made of tin, tin alloy, silver, or silver alloy. The bearing 2 and the housing 3 can be fixed with high strength because they are fixed by diffusion bonding using the bonding material 4.

  In this embodiment, since the sizing process is performed in a state where the bearing 2 is fixed to the housing 3, it is not necessary to size the bearing 2 before incorporating the bearing 2 into the housing 3. In addition, since the sizing process is performed with the bearing 2 fixed to the housing 3, for example, when the inner surface of the bearing 2 is deformed when the bearing 2 is assembled into the housing 3, or the bearing 2 is fixed to the housing 3. Even when the shaft core is tilted in this state, such a problem can be completely solved. Furthermore, in this embodiment, the bearing 2 is assembled into the bearing holding hole 30 of the housing 3 by light press-fitting, so that the necessary minimum sizing is sufficient. Therefore, it is possible to efficiently manufacture the bearing 2 having high accuracy of the inner diameter size, the roundness, and the cylindricity.

  In addition, in the present embodiment, in the bearing 2, the radially outer side of the portion to be sized with respect to the shaft hole 20 is held directly by the first fixing jig 51 and the second fixing jig 52 or via the housing 3. Therefore, deformation and damage of the bearing 2 during sizing can be prevented. Further, when the bearing 2 is assembled into the housing 3 and the bearing 2 is pressed inward by the housing 3 and the shaft hole 20 is deformed, the fixed portion between the housing 3 and the bearing 2 (small diameter portion 31 of the housing 3). Even in this case, in this embodiment, in the housing 3, the portion positioned in the radial direction of the fixing portion (the small diameter portion 31 of the housing 3) between the housing 3 and the bearing 2 is positioned in the housing 3. Since the portion to be held is held by the first fixing jig 51, deformation and damage of the bearing 2 during sizing can be prevented. In particular, in this embodiment, only a part of the bearing holding hole 30 in the axial direction L (the inner peripheral surface of the small diameter portion 31) is fixed to the outer peripheral surface 21 of the bearing 2, and the bearing 2 is only a part of the axial direction L. Is inserted into the bearing holding hole 30 of the housing 3, a force is locally applied to the bearing 2 during sizing. According to this embodiment, the bearing 2 and the housing 3 are connected to the first fixing jig 51 and Since it is held by the second fixing jig 52, deformation and damage of the bearing 2 during sizing can be reliably prevented.

  Furthermore, when the bearing 2 is formed of a sintered body, the amount of the copper-coated iron powder is relatively high from 70% by weight to 98% by weight. It has. In addition, when copper-coated iron powder is used at a high blending ratio of 70 wt% to 98 wt%, copper can be efficiently exposed on the surface, and the exposure ratio of iron on the inner peripheral surface of the shaft hole 20 is correspondingly increased. The area ratio can be 20% or less, and further 10% or less. For this reason, since the inner peripheral surface of the shaft hole 20 is soft, correction by grinding and crushing in the sizing process can be easily performed, and scratches are not easily generated during sizing. Therefore, when the bearing 2 is assembled in the housing 3 in the assembly process of the bearing device 1, for example, even when the inner diameter dimension of the bearing 2 changes due to low inner diameter accuracy of the housing 3, A sufficient amount of correction can be performed on the inner peripheral surface of the shaft 20, and sufficient accuracy can be obtained for the inner diameter of the shaft hole 20. Furthermore, when copper-coated iron powder is used at a high blending ratio of 70% to 98% by weight, even when copper is exposed efficiently, the copper-coated iron powder has a copper layer coverage of 28% to 42% by weight. Good. Such a copper-coated iron powder having a low coverage is less expensive than a copper-coated iron powder having a high coverage, so that the material cost for manufacturing the bearing 2 can be reduced. Furthermore, since copper-coated iron powder is used, the amount of copper itself may be small even when copper is efficiently exposed. Therefore, as for the expansion coefficient, the thermal expansion coefficient can be made equivalent to that of the martensitic stainless material frequently used for the rotary shaft 10, and stable bearing characteristics are exhibited even when the operating temperature changes.

[Embodiment 2]
FIG. 4 is an explanatory diagram showing the cooling process up to the manufacturing process of the bearing device 1 of the present embodiment. Since the basic configuration of the present embodiment is the same as that of the first embodiment, the description of the overall configuration will be made with reference to FIG.

  As shown in FIGS. 1 (a) and 1 (b), the bearing device 1 of this embodiment is also a sintered oil impregnated radial bearing device, like the first embodiment, and has a shaft hole 20 penetrating in the axial direction L. And a cylindrical housing 3 having a bearing holding hole 30 into which the bearing 2 is inserted. The outer peripheral surface 21 of the bearing 2 and the bearing holding hole 30 The peripheral surface 35 is fixed. The housing 3 is made of a ferrous metal including SUS and the like, and is made of a pressed product. The housing 3 and the bearing 2 are fixed by diffusion bonding using a bonding material 4 made of silver between the outer peripheral surface 21 of the bearing 2 and the bearing holding hole 30.

  In the housing 3, only the inner peripheral surface 35 of the small diameter portion 31 in the bearing holding hole 30 is fixed to the outer peripheral surface 21 of the bearing 2. The bearing 2 is made of a sintered body formed by sintering a green compact 29 of copper-coated iron powder. The bearing 2 is fixed to the inner peripheral surface 35 such that only a part of the outer peripheral surface 21 in the axial direction L is in contact with the inner peripheral surface 35 of the bearing holding hole 30. In addition, sizing is performed on at least a portion of the inner peripheral surface of the shaft hole 20 that is located on the radially inner side with respect to a fixing portion between the housing 3 and the bearing 2. The bearing 2 is impregnated with oil, and the bearing 2 is configured as a sintered oil-impregnated bearing.

  Hereinafter, the configuration of the bearing device 1 of the present embodiment will be described in detail with reference to FIG. 4 while describing the manufacturing method of the bearing device 1 of the present embodiment.

  In order to manufacture the bearing device 1 of the present embodiment, first, as shown in FIG. 4A, a copper-coated iron powder is molded in a mold to form a green compact 29 (bearing 2 before sintering). obtain.

  On the other hand, as shown in FIG. 4B, after the cylindrical housing 3 is obtained by pressing the ferrous metal, in the bonding material layer forming step, as shown in FIG. A layer of the bonding material 4 is formed on the inner peripheral surface 35 of the bearing holding hole 30 with silver having the highest melting point among tin, tin alloy, silver, and silver alloy. In this embodiment, since the layer of the bonding material 4 is formed by plating, the layer of the bonding material 4 is formed on all of the inner peripheral surface 35 and the outer peripheral surface of the housing 30.

  Next, as shown in FIG. 4 (d), in the bearing assembling step, the bearing 2 is assembled into the bearing holding hole 30 of the housing 3 by light press fitting.

  Next, as shown in FIG. 4 (e), in the heating step, the temperature is equal to or lower than the temperature at which the material constituting the bearing 2 and the housing 3 is melted and is equal to or higher than the temperature at which the bonding material 4 is melted. The bonding material 4, the bearing 2, and the housing 3 are heated to fix the outer peripheral surface 21 of the bearing 2 and the inner peripheral surface 35 of the small diameter portion 31 of the bearing holding hole 30 by liquid phase diffusion bonding of the bonding material 4. At that time, the heating condition is set to a temperature of 750 to 850 ° C. in an ammonia decomposition gas atmosphere, and the green compact 29 is sintered to form the bearing 2 made of the sintered body.

  Thereafter, the sizing process described with reference to FIGS. 3A to 3D is performed as in the first embodiment. In the present embodiment, the sizing process is the same as that in the first embodiment, and thus the description thereof is omitted.

  As described above, the bearing device 1 of the present embodiment is also made of a sintered oil-impregnated bearing since the bearing 2 is made of a sintered body of copper-coated iron powder and formed of an iron-based metal, as in the first embodiment. Even when used as, the wear resistance and the like are good. Moreover, although the bearing 2 is formed with the iron-type metal, it consists of a sintered compact of copper covering iron powder also in an iron-type metal. For this reason, in the bearing 2, since most of the surface of the iron powder is covered with copper, the bearing 2 and the housing 3 can be fixed by diffusion bonding using silver. For example, the bearing 2 and the housing 3 can be fixed with high strength, and the same effects as those of the first embodiment can be obtained.

  Further, in this embodiment, silver is used as the bonding material 4, the bearing 2 and the housing 3 are heated, and the outer peripheral surface 21 of the bearing 2 and the small diameter portion 31 of the bearing holding hole 30 are formed by liquid phase diffusion bonding of the bonding material 4. In performing the heating process for fixing the inner peripheral surface 35, silver is used as the bonding material 4 and the heating temperature is set high. For this reason, the compacting body 29 can be sintered at the same time, and the bearing 2 made of the sintered body can be obtained. Therefore, since the number of manufacturing steps can be reduced, productivity can be improved.

[Other embodiments]
In the above embodiment, only a part of the outer peripheral surface 21 of the bearing 2 in the axial direction is fixed to the inner peripheral surface 35 of the housing 3, but the entire outer peripheral surface 21 of the bearing 2 is on the inner peripheral surface of the housing 3. The present invention may be applied to a bearing device that is fixed.

  In the above embodiment, only a part of the inner peripheral surface 35 of the bearing holding hole 30 in the axial direction is fixed to the outer peripheral surface 21 of the bearing 2, but the entire inner peripheral surface 35 of the bearing holding hole 30 is the bearing 2. You may apply this invention to the bearing apparatus currently fixed to the outer peripheral surface of this.

  In the above embodiment, the shaft hole 20 of the bearing 2 is a through hole. However, the present invention may be applied to a bearing device in which the shaft hole 20 has a bottom and serves as both a radial bearing and a thrust bearing. .

  Moreover, in the said form, although the bearing apparatus 1 was the structure which supports the rotating shaft 10, you may apply this invention, when the bearing apparatus 1 is rotatably supported by the fixed shaft.

(A), (b) is respectively sectional drawing of the bearing apparatus which concerns on Embodiment 1 of this invention, and sectional drawing of the state which supports the rotating shaft by this bearing apparatus. It is explanatory drawing which shows to a cooling process among the manufacturing processes of the bearing apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows a sizing process among the manufacturing processes of the bearing apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows to a cooling process among the manufacturing processes of the bearing apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ・ ・ Bearing device 2 ・ ・ Bearing 3 ・ ・ Housing 4 ・ ・ Bonding material 20 ・ ・ Shaft hole 29 ・ ・ Green compact 30 ・ ・ Bearing holding hole 50 ・ ・ Sizing device 51 ・ ・ First fixing jig 52 .. Second fixing jig 53 .. Sizing bar 54.. Guide member

Claims (10)

A bearing having a shaft hole formed in the axial direction and a housing having a bearing holding hole into which the bearing is inserted, and an outer peripheral surface of the bearing and an inner peripheral surface of the bearing holding hole are fixed to each other In the bearing device,
The bearing is made of a sintered body of copper-coated iron powder,
The housing is made of a ferrous metal,
The bearing and the housing are fixed by diffusion bonding using a bonding material made of tin, tin alloy, silver, or silver alloy between the outer peripheral surface of the bearing and the inner peripheral surface of the bearing holding hole. A bearing device characterized by that.   2. The bearing device according to claim 1, wherein, of the outer peripheral surface of the bearing, only a part in the axial direction is fixed to the inner peripheral surface in a state of being in contact with the inner peripheral surface of the bearing holding hole.   3. The bearing device according to claim 1, wherein, of the inner peripheral surface of the bearing holding hole, only a part in the axial direction is fixed to the outer peripheral surface in a state of being in contact with the outer peripheral surface of the bearing. .   The sizing is given to the part located in the radial direction inner side of the fixed part of the said housing and the said bearing at least among the internal peripheral surfaces of the said shaft hole. The bearing device according to item. A bearing having a shaft hole formed in the axial direction and a housing having a bearing holding hole into which the bearing is inserted, and an outer peripheral surface of the bearing and an inner peripheral surface of the bearing holding hole are fixed to each other In the manufacturing method of the bearing device,
In order to form the bearing, while forming by sintering against a green compact of copper-coated iron powder,
About the housing, formed of iron-based metal,
In making the bearing fixed in the housing,
A bonding material layer forming step of forming a bonding material layer made of tin, a tin alloy, silver, or a silver alloy on the inner peripheral surface of the bearing holding hole of the housing;
A bearing assembly step of incorporating the bearing into the bearing holding hole of the housing;
A heating step of heating the bonding material and fixing the outer peripheral surface of the bearing and the inner peripheral surface of the bearing holding hole by diffusion bonding of the bonding material;
The manufacturing method of the bearing apparatus characterized by performing. Before performing the bearing assembly step, perform sintering on the green compact,
6. The method for manufacturing a bearing device according to claim 5, wherein, in the bearing assembling step, the sintered bearing is incorporated into the bearing holding hole of the housing. In the bonding material layer forming step, the layer of the bonding material is formed of silver,
In the bearing incorporation step, the bearing is incorporated into the bearing holding hole of the housing in the state of the green compact before sintering,
The method for manufacturing a bearing device according to claim 5, wherein the green compact is sintered by heating in the heating step. In the bearing incorporation step, of the outer peripheral surface of the bearing, only a part in the axial direction is in contact with the inner peripheral surface of the bearing holding hole,
8. A bearing device that is fixed to the inner peripheral surface in a state in which only a part of the outer peripheral surface of the bearing is in contact with the inner peripheral surface of the bearing holding hole is manufactured. The manufacturing method of the bearing apparatus as described in any one of these. In the bearing assembling step, of the inner peripheral surface of the bearing holding hole of the housing, only a part in the axial direction is in contact with the outer peripheral surface of the bearing,
9. The bearing device fixed to the outer peripheral surface in a state where only a part of the inner peripheral surface of the bearing holding hole is in contact with the outer peripheral surface of the bearing is manufactured. The manufacturing method of the bearing apparatus as described in any one.   The method for manufacturing a bearing device according to any one of claims 5 to 9, wherein a sizing step of sizing the inner peripheral surface of the shaft hole is performed after the heating step.

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