Manufacturing method of rolling bearing unit

Abstract

To provide a rolling bearing unit production method in which, upon integrating a rolling bearing with a metallic or resinous housing, cost reduction is attained by facilitating the production process without requiring an assembly operation, a rolling bearing push-in operation and complicated processing.SOLUTION: Provided is a production method for a rolling bearing unit in which a rolling bearing is integrated with a metallic or resinous housing, where the rolling bearing is attached to a housing mold as a core, and molten metal or a molten resin is made to flow into the mold so as to be solidified.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a rolling bearing unit in which a rolling bearing and a metal or resin housing are integrated, and to the rolling bearing unit. [Background technology]

[0002] Conventionally, rolling bearing units such as pillow blocks and plummer blocks, in which a rolling bearing is integrated with a metal housing, have been widely used, as shown in Patent Documents 1 and 2. Rolling bearing units in which a rolling bearing is integrated with a resin housing are also widely known.

[0003] 6 is a cross-sectional view showing a schematic diagram of a conventional plummer block as an example of the rolling bearing unit 1. The housing 100 has a two-piece structure consisting of an upper housing 100A and a lower housing 100B, and semi-cylindrical bearing accommodating portions 101A and 101B are formed in the upper housing 100A and the lower housing 100B, respectively. The upper housing 100A is then placed over the lower housing 100B, and the upper half of the rolling bearing 10 is accommodated in the bearing accommodating portion 101A of the upper housing 100A, and the upper housing 100A and the lower housing 100B are bolted together so that the lower half of the rolling bearing 10 is accommodated in the bearing accommodating portion 101B of the lower housing 100B, and the upper half of the rolling bearing 10 is accommodated in the bearing accommodating portion 101A of the upper housing 100A. As a result, the upper housing 100A and the lower housing 100B are connected together, and the rolling bearing 10 is accommodated in the cylindrical bearing accommodating portion 101 formed by the bearing accommodating portions 101A and 101B, and the rolling bearing 10 and the housing 100 are integrated together.

[0004] However, since the inner peripheral surfaces of the bearing accommodating portion 101A of the upper housing 100A and the bearing accommodating portion 101B of the lower housing 100B come into contact with the outer peripheral surface of the outer ring of the rolling bearing 10, they must be machined with sufficiently high precision, which makes the machining process time-consuming. Furthermore, the mating surface 102A of the upper housing 100A and the mating surface 102B of the lower housing 100B must also be machined. Furthermore, a process is required in which the rolling bearing 10 is accommodated in the bearing accommodating portion 101B of the lower housing 100B, and the upper housing 100A is then placed on top and bolted. This requires assembly work and complicated machining, which inevitably results in high costs.

[0005] Although not shown in the drawings, in the case of a pillow block, although the housing is not divided into two parts, a process for pressing in the rolling bearing and machining of the inner peripheral surface of the bearing accommodating portion are required.

[0006] In addition, excessive torque or load applied to the rolling bearing may cause the outer ring of the rolling bearing to slide against the inner surface of the housing, or may cause creep, in which the raceway of the rolling bearing moves relative to the shaft or housing during operation. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-52719 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-128701 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of these problems, and aims to simplify the manufacturing process and reduce costs when integrating a rolling bearing with a metal or resin housing, without requiring assembly work, pressing the rolling bearing into place, or complex processing. [Means for solving the problem]

[0009] The above object of the present invention is achieved by the following configuration [1] relating to a manufacturing method of a rolling bearing unit.

[0010] [1] A method for manufacturing a rolling bearing unit in which a rolling bearing and a metal or resin housing are integrated, A method for manufacturing a rolling bearing unit, comprising: mounting the rolling bearing as a core in a mold for the housing; pouring molten metal or molten resin into the mold; and allowing it to solidify.

[0011] Furthermore, preferred embodiments of the present invention relating to a manufacturing method for a rolling bearing unit relate to the following [2] to [5].

[0012] [2] A method for manufacturing a rolling bearing unit according to [1], wherein the molten metal or molten resin is poured into the mold and solidified while cooling at least one of the outer ring and the inner ring of the rolling bearing. [3] A method for manufacturing a rolling bearing unit according to [1] or [2], wherein the molten metal or molten resin is poured into the mold and solidified while supplying lubricating oil to the space between the inner ring and the outer ring of the rolling bearing. [4] A method for manufacturing a rolling bearing unit according to [1] or [2], wherein the molten metal or molten resin is poured into the mold and solidified while the rolling bearing is filled with grease. [5] The method for manufacturing a rolling bearing unit according to any one of [1] to [4], wherein the molten metal is a molten aluminum alloy or magnesium alloy.

[0013] The above object of the present invention is also achieved by the following configurations [6] and [7] relating to the rolling bearing unit.

[0014] [6] A rolling bearing unit in which a rolling bearing and a metal housing are integrated, A rolling bearing unit is a casting of the housing with the rolling bearing as a core. [7] A rolling bearing unit in which a rolling bearing and a plastic housing are integrated, A rolling bearing unit is an injection-molded product formed by molding the housing with the rolling bearing as a core. [Effects of the Invention]

[0015] According to the present invention, when integrating a rolling bearing with a metal or resin housing, no assembly work, no work to press the rolling bearing in, or complex processing of the housing is required, making the manufacturing process easier and reducing costs. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic view showing a first embodiment of a method for manufacturing a rolling bearing unit according to the present invention. [Figure 2] FIG. 2 is a schematic view showing an example of a rolling bearing unit according to the present invention. [Figure 3] FIG. 3 is a schematic view showing a second embodiment of the method for manufacturing a rolling bearing unit according to the present invention. [Figure 4] FIG. 4 is a schematic view showing a third embodiment of the method for manufacturing a rolling bearing unit according to the present invention. [Figure 5] FIG. 5 is a schematic view showing a fourth embodiment of the method for manufacturing a rolling bearing unit according to the present invention. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an example of a conventional plummer block. DETAILED DESCRIPTION OF THE INVENTION

[0017] As a result of extensive research into solving the above problems, the inventors have found that it is effective to use a rolling bearing as a core and to integrate it with a metal housing by casting, or with a resin housing by injection molding.

[0018] The present invention will be described in detail below by way of examples of embodiments, but the present invention is not limited thereto. Various modifications and improvements can be made to the embodiments, and such modifications and improvements can also be included in the present invention.

[0019] [Embodiment 1] The rolling bearing unit of the present invention is formed by integrating a rolling bearing with a metal or resin housing by casting.

[0020] FIG. 1 is a schematic diagram showing a first embodiment of a manufacturing method for a rolling bearing unit according to the present invention. During manufacturing, as shown in FIG. 1, rolling bearing 10 is first mounted as a core in lower housing mold 50B, which is then covered with upper mold 50A and clamped. After that, molten metal or molten resin (not shown) is poured into cavity 55 between rolling bearing 10, upper mold 50A, and lower mold 50B through a pouring spout (not shown) formed in an appropriate position in upper mold 50A, filling cavity 55 between rolling bearing 10, upper mold 50A, and lower mold 50B with the molten metal or molten resin. Ring-shaped grooves 51A and 51B corresponding to the outer and inner diameters of rolling bearing 10 are formed in upper mold 50A and lower mold 50B, respectively, to position rolling bearing 10. The shape of cavity 55 can be selected arbitrarily, such as the shape of housing 100 shown in FIG. 6.

[0021] There are no limitations on the rolling bearing 10, and it can be any type such as a ball bearing, roller bearing, or self-aligning bearing. Furthermore, rough machining of the outer peripheral surface of the outer ring, shot peening, or groove cutting perpendicular to the sliding direction can improve adhesion to the housing 100, making it possible to further suppress creep.

[0022] There is no restriction on the type of metal to be used as the molten metal, and any metal can be selected in consideration of the strength of the housing. However, since the molten metal comes into contact with the outer ring of the rolling bearing 10, and in consideration of the thermal influence, a metal with a low melting point is preferable, such as an aluminum alloy or a magnesium alloy. Furthermore, the linear expansion coefficient of iron is 11.8 to 12.1 [×10 -6 / K], while magnesium is 25.4-26[×10 -6 / K], aluminum is 23 to 23.5[×10 -6 / K], the molten metal tends to shrink when it solidifies, which creates a negative clearance between the rolling bearing 10 and the housing 100, making it difficult for the housing to slide between the bearing and the rolling bearing. Therefore, it can be said that an aluminum alloy or a magnesium alloy is suitable. The expansion coefficient of resin is generally 11 to 20 [×10 -5 / K], which is relatively large like the above-mentioned magnesium and aluminum, and therefore it is thought that sliding between the housing and bearing will be difficult even in the case of a rolling bearing unit formed by injection molding in which the rolling bearing and resin housing are integrated.

[0023] The entire assembly is then allowed to cool naturally, solidifying the molten metal or molten resin filled in the cavity 55, and the mold is then opened to obtain the rolling bearing unit 1 according to this embodiment as shown in Figure 2. This rolling bearing unit 1 is not a two-piece housing 100 as in the conventional plummer block shown in Figure 6, but is a cast or injection-molded product in which the housing 100 and rolling bearing 10 are integrated. Therefore, there are no mating surfaces 102A, 102B between the upper housing 100A and the lower housing 100B, and no machining of the inner circumferential surface of the bearing receiving portion 101 is required. Furthermore, the process of pressing the rolling bearing 10 into the bearing receiving portion 101 is also unnecessary.

[0024] [Embodiment 2] Figure 3 is a schematic diagram showing a second embodiment of the method for manufacturing a rolling bearing unit according to the present invention. In order to reduce the thermal effect of the molten metal or molten resin on the rolling bearing 10, a cooling water circulation pipe 60 corresponding to the shaft (not shown) inserted into the inner ring of the rolling bearing 10 can be used, as shown in Figure 3. By circulating cooling water through this cooling water circulation pipe 60 while pouring the molten metal or molten resin into the cavity 55, the inner ring of the rolling bearing 10 is cooled in order from the rolling elements to the outer ring, thereby cooling the entire bearing.

[0025] [Embodiment 3] Figure 4 is a schematic diagram showing a third embodiment of the method for manufacturing a rolling bearing unit according to the present invention. In order to reduce the thermal effect of molten metal or molten resin on rolling bearing 10, as shown in Figure 4, it is possible to provide cooling water flow passages 70 in each of upper mold 50A and lower mold 50B, aligned with the inner and outer diameters of rolling bearing 10, and to pour molten metal or molten resin into cavity 55 while circulating cooling water. The cooling water flow passages 70 allow rolling bearing 10 to be cooled from the side. The cooling water flow passage 70 may be configured to circulate within the upper die 50A and cool the upper parts of the inner and outer rings of the rolling bearing 10. Furthermore, the cooling water flow passage 70 may be configured to circulate within the lower die 50B and cool the lower parts of the inner and outer rings of the rolling bearing 10.

[0026] Although not shown, the cooling water flow pipe 60 described in the second embodiment can also be used in combination. This increases the cooling effect of the rolling bearing 10, and makes it possible to further reduce the thermal influence. In addition, in FIG. 4, the upper and lower molds are set up so that the parting lines are horizontal, but the molds may also be set up horizontally, i.e., so that the parting lines are vertical.

[0027] [Embodiment 4] Figure 5 is a schematic diagram showing a fourth embodiment of the method for manufacturing a rolling bearing unit according to the present invention. In order to reduce the thermal effect of the molten metal or molten resin on the rolling bearing 10, as shown in Figure 5, it is possible to provide a lubricating oil distribution pipe 80 that penetrates the cavity 55 of the lower mold 50B and further penetrates the outer ring 11 of the rolling bearing 10, and to pour the molten metal or molten resin into the cavity 55 while supplying lubricating oil to the space between the outer ring 11 and inner ring 12 of the rolling bearing 10 (bearing space) through the lubricating oil distribution pipe 80. The lubricating oil acts as a refrigerant, allowing the rolling bearing 10 to be cooled from the bearing space, i.e., from the inside.

[0028] The lubricating oil flow pipe 80 can be used as an oil supply hole for the rolling bearing 10 in the resulting rolling bearing unit 1. Therefore, after manufacturing, new lubricant can be supplied through the oil supply hole, and the lubricating oil used as a coolant during manufacturing can be drained from the rolling bearing 10.

[0029] Furthermore, the cooling water flow pipe 60 and the cooling water flow passage 70 described in the second and third embodiments may be used in combination.

[0030] [Embodiment 5] Although not shown in the drawings, in the first to third embodiments, the rolling bearing 10 can also be used with grease filled in the bearing space. The grease acts as a coolant and contributes to cooling the rolling bearing 10.

[0031] It takes a short time for the molten metal or molten resin to solidify, and general bearing grease can withstand this without thermal decomposition. [Explanation of symbols]

[0032] 1 Rolling bearing unit 10. Rolling bearings 11 Outer ring 12 Inner Circle 50A Upper mold 50B Lower mold 51A Groove 51B Groove 55 void 60 Cooling water flow pipe 70 Cooling water passage 80 Lubricating oil distribution pipe 100 Housing 101 bearing housing

Claims

1. A method for manufacturing a rolling bearing unit in which a rolling bearing and a metal or resin housing are integrated, comprising: The rolling bearing is mounted as a core in a mold for the housing, a method for manufacturing a rolling bearing unit, comprising: pouring molten metal or molten resin into the mold and allowing it to solidify while supplying lubricating oil to the space between the inner ring and the outer ring of the rolling bearing through a lubricating oil distribution pipe that is provided so as to pass through the mold and the outer ring.

2. 2. The method for manufacturing a rolling bearing unit according to claim 1, wherein the molten metal or the molten resin is poured into the mold and solidified while cooling at least one of the outer ring and the inner ring of the rolling bearing.

3. 3. The method for manufacturing a rolling bearing unit according to claim 1, wherein the molten metal is a molten aluminum alloy or a molten magnesium alloy.

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