Manufacturing method for press-molded products

Abstract

To provide a method for manufacturing a press-fit molded product capable of arranging a member at a proper position on an inner ring and / or outer ring of a ball bearing.SOLUTION: A method for manufacturing a press-fit molded product comprises: pressing-fit a shaft 33 into an annular part of an inner ring of a first ball bearing 31; along with the press-fitting operation, making it possible to perform a second press-fitting of an outer ring of a second ball bearing 31a into a housing 32 at the same time as the press-fitting operation; and during the press-fitting and the second press-fitting, assembling a press-fit molded product with a tolerance smaller than an elastic displacement amount of a member and / or tool.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The present invention relates to a method for producing an extrusion molded article. [Background technology]

[0002] A ball bearing is a device in which a member is fixed to its inner and outer rings while generating friction, and the members fixed to the inner and outer rings also rotate in conjunction with the rotational movement of the inner and outer rings.

[0003] Patent Document 1 discloses an invention aimed at providing a rotary drive device including a bearing device capable of applying an appropriate preload to two ball bearings. For example, as shown in Fig. 28, in a rotary drive device 101, when applying preload to a first ball bearing 81 and a second ball bearing 82 of a bearing device 131, a spacer member 86 is provided between the inner rings 811 and 821, while a pair of position determining portions (a first position determining portion 84 and a second position determining portion 89) are provided between the outer rings 812 and 822 and among the outer positions of the outer rings 812 and 822 in the direction of the motor axis L, for determining the separation distance between the outer rings 812 and 822 only at the outer positions. Therefore, the spacer member 86 can be applied to the first ball bearing 81 and the second ball bearing 82 by providing it only on the inner rings 811 and 821 side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-148169 A Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, it is difficult to apply an appropriate pressure to the ball bearing, and similarly, it is difficult to position the member fixed to the inner and outer rings by press-fitting in the appropriate position on the ball bearing.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a method for manufacturing a press-fit molded product that enables a member to be disposed at an appropriate position on the inner ring and / or outer ring of a ball bearing. [Means for solving the problem]

[0007] In order to achieve the above object, the manufacturing method of the press-fit molded product of the present invention makes it possible to press a shaft into the annular portion of the inner ring of a ball bearing, and during the press-fitting, assembly can be performed with a tolerance smaller than the elastic displacement of the parts and / or tools.

[0008] In order to achieve the above-mentioned object, the manufacturing method of the press-fit molded product of the present invention makes it possible to perform a second press-fitting in which a housing is pressed into the outer ring of a ball bearing, and during the second press-fitting, assembly can be performed with a tolerance smaller than the elastic displacement of the parts and / or tools.

[0009] In order to achieve the above object, the method for producing an injection-molded product of the present invention comprises the steps of: A method for producing a press-fit molded article comprising a first ball bearing, a second ball bearing, a housing, and a shaft, the method comprising the steps of: The shaft is press-fitted into the annular portion of the inner ring of the first ball bearing, and as the shaft is pressed into the outer ring of the second ball bearing, At least a portion of the first ball bearing is housed The second press-fitting is performed on the housing at the same time as the press-fitting operation, and during the press-fitting and the second press-fitting, A press-fitted product is assembled by applying vibration to the shaft, the housing, the first ball bearing, and the second ball bearing in order to suppress the occurrence of variations in the press-fitted state that occur during the press-fitting and / or the second press-fitting.

[0010] In order to achieve the above-mentioned object, the method for manufacturing a press-fit molded product of the present invention includes a step of pressing a shaft into the annular portion of the inner ring of a ball bearing, and / or a second press-fit step of pressing a housing into the outer ring of the ball bearing, and in carrying out this step, a thrust load is applied to the ball bearing to create a step between the inner ring pressing surface and the outer ring pressing surface, making it possible to assemble the product with a tolerance smaller than the elastic displacement of the parts and / or tools during the press-fit process.

[0011] In order to achieve the above-mentioned object, the manufacturing method of the press-fit molded product of the present invention includes a second press-fitting step in which a housing is press-fitted into the outer ring of a ball bearing, and the inner surface of the housing is step-free and can be assembled with a tolerance smaller than the elastic displacement of the parts and / or tools.

[0012] Here, when assembling the press-fit molded product, the members and / or the tool may be vibrated with a tolerance smaller than the amount of elastic displacement of the members and / or the tool. Effect of the Invention

[0013] The present invention can provide a method for producing a press-fit molded product that allows a component to be disposed at an appropriate position on the inner ring and / or outer ring of a ball bearing. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is an exploded perspective view of components of a press-fitting device and a press-fitted product according to the first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of a press-fitting device according to the first embodiment of the present invention. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2, showing a state before the press machine starts pressing. [Figure 4] 3 is a cross-sectional view taken along line AA in FIG. 2, showing the press in a lowered state. [Diagram 5] 3 is a cross-sectional view taken along the line AA in FIG. 2, showing a state in which the press machine has been lowered and then raised. [Figure 6] 1 is a perspective view of a press-fitted molded product produced by a method for producing a press-fitted molded product according to a first embodiment of the present invention. FIG. [Figure 7] 1 is a front view of a press-fitted molded product produced by a method for producing a press-fitted molded product according to a first embodiment of the present invention. FIG. [Figure 8] 8 is a cross-sectional view of FIG. 7 taken along line B-B. [Figure 9] FIG. 11 is an exploded perspective view of a press-fitting device and components according to a second embodiment of the present invention. [Figure 10]FIG. 11 is a plan view of a press-fitting device according to a second embodiment of the present invention. [Figure 11] 11 is a cross-sectional view taken along line CC in FIG. 10, showing a state before the press machine starts pressing. [Figure 12] 11 is a cross-sectional view taken along line CC in FIG. 10, showing the press machine in a lowered state. [Figure 13] 11 is a cross-sectional view taken along the line CC in FIG. 10, showing a state in which the press machine has been lowered and then raised. [Figure 14] FIG. 11 is a perspective view of a press-fitted molded product produced by a method for producing a press-fitted molded product according to a second embodiment of the present invention. [Figure 15] 11 is a front view of a press-fitted molded product produced by a method for producing a press-fitted molded product according to a second embodiment of the present invention. FIG. [Figure 16] FIG. 16 is a cross-sectional view taken along the line DD in FIG. [Figure 17] FIG. 11 is an exploded perspective view of a press-fitting device and components according to a third embodiment of the present invention. [Figure 18] FIG. 11 is a plan view of a press-fitting device according to a third embodiment of the present invention. [Figure 19] FIG. 19 is an E-E sectional view of FIG. 18, showing a state before the press machine starts pressing. [Figure 20] FIG. 19 is an E-E sectional view of FIG. 18, showing the press in a lowered state. [Figure 21] FIG. 19 is an E-E sectional view of FIG. 18, showing a state in which the press machine has been lowered and then raised. [Figure 22] FIG. 11 is a perspective view of a press-fitted molded product produced by a method for producing a press-fitted molded product according to a third embodiment of the present invention. [Figure 23] FIG. 11 is a front view of a press-fitted molded product produced by a method for producing a press-fitted molded product according to a third embodiment of the present invention. [Figure 24] 24 is a cross-sectional view of FIG. 23 shown in FIG. [Diagram 25] 21 is a diagram showing a modified example of the present embodiment, which corresponds to an enlarged view of the vicinity of the upper jig 30 in FIG. 19 and FIG. 20. [Figure 26] This is a figure corresponding to FIG. 24. [Figure 27]FIG. 27 is a diagram showing a modified example of the present embodiment obtained by modifying FIG. 26. [Figure 28] FIG. 1 is a diagram illustrating a conventional technique. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Details of the manufacturing method of the press-molded product according to the first embodiment) Hereinafter, the method for producing the press-fit molded product according to the first embodiment will be described with reference to FIGS. 1, 2, 3, 4, 5, 6, 7, and 8. FIG.

[0016] The press-fitting device 1 has a press machine having a frame 5 and a slide 6. A vibrator 14 is fixedly disposed on the bottom surface 5a of the frame 5. The vibrator 14 is made of a piezoelectric element. A lower jig 13 is fixedly disposed on the upper surface of the vibrator 14 with a hole portion 13a facing upward. A cylindrical radial ball bearing 12 is fitted into the hole portion 13a of the lower jig 13 with the flat portion 12a facing downward.

[0017] Then, the upper jig 10 is fixedly disposed on the lower surface 6a of the slide 6 with one flat surface facing downward and the other flat surface facing the lower jig 13. A hole 10a into which the shaft 11 can be inserted and held is formed in the center of one flat surface of the upper jig 10. Furthermore, a through hole 10b is formed which is concentrically connected to the hole 10a and has a smaller diameter than the hole 10a. This through hole 10b serves as a vacuum suction hole (piping not shown). This vacuum suction always suctions and holds the workpiece. When the workpiece is to be removed, it is pulled out by hand while being sucked. The shaft 11 is inserted and held in the hole 10a. The above configuration (frame 5, slide 6, vibrator 14, lower jig 13, upper jig 10) constitutes the press-fitting device 1. The remaining parts are members that constitute the press-fitted molded product. The above is the state shown in FIG. 3.

[0018] From the state shown in Fig. 3, slide 6 is lowered (press lowered) to insert, or press-fit, shaft 11 into the inner ring of radial ball bearing 12. The amount of insertion is the amount by which shaft 11 protrudes from hole 10a of upper jig 10. This is the state shown in Fig. 4.

[0019] After the state shown in Fig. 4, the slide 6 is raised (press rise). Then, the shaft 11 is press-fitted into the inner ring of the radial ball bearing 12, and the radial ball bearing 12 is attached to the shaft 11. This is the state shown in Fig. 5.

[0020] 3, 4 and 5, in the state shown in Fig. 4, that is, when shaft 11 is inserted, i.e., pressed into, the annular portion of the inner ring of radial ball bearing 12, vibrator 14 is operated. In other words, press-fitting device 1 is capable of press-fitting shaft 11 into the annular portion of the inner ring of radial ball bearing 12, and can apply vibration to radial ball bearing 12 via lower jig 13 during press-fitting. This vibration applies ultrasonic vibration to radial ball bearing 12 and shaft 11 during press-fitting.

[0021] After the state shown in Fig. 5 is reached, the shaft 11 inserted and gripped in the hole 10a is removed, and the press-fitted product, that is, the workpiece, can be taken out, as shown in Fig. 6, Fig. 7, and Fig. 8. This workpiece has a radial ball bearing 12 attached to one end of the shaft 11.

[0022] The manufacturing method of the press-fit molded product of the first embodiment is summarized below. The shaft 11 can be press-fitted into the annular portion of the inner ring of the radial ball bearing 12, and vibration is applied to the shaft 11 and / or the radial ball bearing 12 during the press-fitting.

[0023] (Details of the method for manufacturing the press-molded product according to the second embodiment of the present invention) Hereinafter, the method for producing the press-fit molded product according to the second embodiment will be described with reference to FIGS. 9, 10, 11, 12, 13, 14, 15, and 16. FIG.

[0024] The press-fitting device 2 has a press machine having a frame 5 and a slide 6, similar to the first embodiment. A vibrator 24 is fixedly disposed on the bottom surface 5a of the frame 5. The vibrator 24 is made of a piezoelectric element. A lower jig 23 is fixedly disposed on the upper surface of the vibrator 24 with a shaft portion 23a facing upward.

[0025] The upper jig 20 is fixedly disposed on the lower surface 6a of the slide 6 with the smaller of its two flat surfaces facing downward and the through hole 20a facing the shaft portion 23a of the lower jig 23. The through hole 20a is an interference avoidance hole for the protrusion (shaft portion 23a described below) of the lower jig 23, and is not subjected to vacuum suction or the like as is the through hole 10b. The above configuration (frame 5, slide 6, vibrator 24, lower jig 23, upper jig 20) constitutes the press-fitting device 2. The remaining parts are members that constitute the press-fitted molded product.

[0026] Then, the shaft portion 23a of the lower jig 23 is inserted through the opening 22b into the hole portion 22a of the rectangular prism-shaped hollow housing 22. The opening 22b is a surface in which all surfaces opposite the surface in which the hole portion 22a exists are open. Therefore, it is possible to insert the shaft portion 23a of the lower jig 23 through the opening 22b and further make the shaft portion 23a protrude from the hole portion 22a.

[0027] From the state shown in Fig. 11, slide 6 is lowered (press lowering) and the outer ring of radial ball bearing 21 is inserted, that is, pressed into the inner circumferential surface of hole 22a of housing 22 while generating frictional force (second press-fit). This insertion distance is the distance to step 22c around hole 22a of housing 22. This step 22c serves to support flat portion 21a of radial ball bearing 21 so that it does not fall out of hole 22a of housing 22. This is the state shown in Fig. 12.

[0028] After the state shown in Fig. 12, the slide 6 is raised (press up). Then, the outer ring of the radial ball bearing 21 is press-fitted (second press-fit) into the hole 22a of the housing 22, and the radial ball bearing 21 is attached to the housing 22. This is the state shown in Fig. 13.

[0029] 11, 12 and 13, in the state shown in Fig. 12, that is, the press-fitting device 2 can press-fit (second press-fit) the outer ring of the radial ball bearing 21 into the annular portion (hole portion 22a) of the housing 22, and during the press-fitting (second press-fitting), can apply vibration to the radial ball bearing 21 via the lower jig 23. By this vibration, ultrasonic vibration is applied to the radial ball bearing 21 and the housing 22 during the press-fitting (second press-fitting).

[0030] After the state shown in Fig. 13 is reached, the radial ball bearing 21 inserted and held in the housing 22 is removed, and then the press-fitted product, or so-called workpiece, can be taken out, as shown in Figs. 14, 15, and 16. This workpiece is the radial ball bearing 21 attached to the hole 22a of the housing 22.

[0031] The manufacturing method of the press-fitted product of the second embodiment is summarized below. It is possible to perform a second press-fitting in which the housing 22 is press-fitted into the outer ring of the radial ball bearing 21, and during the second press-fitting, vibration is applied to the housing 22 and / or the radial ball bearing 21.

[0032] (Details of the method for manufacturing the press-molded product according to the third embodiment of the present invention) Hereinafter, a method for producing a press-fitted molded product according to the third embodiment will be described with reference to FIGS.

[0033] The press-fitting device 3, like the first and second embodiments, has a press machine having a frame 5 and a slide 6. A vibrator 35 is fixedly disposed on a bottom surface 5a of the frame 5. The vibrator 35 is made of a piezoelectric element. A lower jig 34 is fixedly disposed on an upper surface of the vibrator 35.

[0034] The flat cylindrical upper jig 30 is fixed to the lower surface 6a of the slide 6 with its flat surface facing upward and facing the lower jig 34. Furthermore, a through hole 30a is formed in the center of the circle of the upper jig 30, penetrating the upper jig 30 in the thickness direction. This through hole 30a serves as a vacuum suction hole (piping not shown). This vacuum suction always sucks and holds the workpiece. When the workpiece is to be removed, it is pulled out by hand while being sucked. The above configuration (frame 5, slide 6, vibrator 35, lower jig 34, upper jig 30) constitutes the press-fitting device 3. The remaining parts (first radial ball bearing 31, second radial ball bearing 31b, housing 32, shaft 33) are members that constitute the press-fitted product.

[0035] 19 will be described below. The cylindrical lower jig 34 has a hollowed-out portion 34a hollowed out into a rectangular parallelepiped on the upper surface, and a circular through-hole 34b penetrating from top to bottom in the center of the bottom surface of the hollowed-out portion 34a. The bottom surface of the lower jig 34 is fixedly disposed on the upper surface of the vibrator 35.

[0036] A rectangular, hollow housing 32 is fitted into the hollowed-out portion 34a. The housing 32 has a circular hole 32a at its upper center when fitted into the hollowed-out portion 34a. The housing 32 has a circular hole 32b at its lower center when fitted into the hollowed-out portion 34a. The inner circumferential surface of the hole 32b fits into the outer ring of the first radial ball bearing 31 so as to generate friction.

[0037] One end of the shaft 33 is fitted and fixed in the recess 30b that is concentrically connected to the through hole 30a of the upper jig 30. The circumferential surface of the shaft 33 is fitted to the inner ring of the second radial ball bearing 31a so as to generate friction. The lower end of the shaft 33 faces the center of the inner ring of the first radial ball bearing 31. This is the state shown in FIG.

[0038] From the state shown in FIG. 19, the slide 6 is lowered (press lowered), and the outer ring of the second radial ball bearing 31a is inserted, i.e., pressed into the inner circumferential surface of the hole 32a of the housing 32 while generating frictional force (second press-in). This insertion distance is the distance to the steps 32c and 32d around the hole 32a of the housing 32. These steps 32c and 32d serve to support the flat surface 31b so that the first radial ball bearing 31 and the second radial ball bearing 31a do not fall from the holes 32a and 32b of the housing 32. The steps 32c and 32d are positioned opposite each other. The lower end of the shaft 33 is inserted into the hole 32a of the housing 32, and then inserted, i.e., pressed into the inner circumferential surface of the inner ring of the first radial ball bearing 31 while generating frictional force, and further inserted into the through hole 34b of the lower jig 34. This is the state shown in FIG.

[0039] After the state shown in Fig. 20, the slide 6 is raised (pressed up). Then, the outer ring of the second radial ball bearing 31a is press-fitted (second press-fit) into the hole 32a of the housing 32, and the radial ball bearing 31 is attached to the housing 32. Furthermore, the shaft 33 leaves the recess 30b of the upper jig 30 and moves into the through-hole 34b of the lower jig 34. This is the state shown in Fig. 21.

[0040] Among the states shown in Fig. 19, Fig. 20, and Fig. 21, in the state shown in Fig. 20, that is, the outer ring of the second radial ball bearing 31a is inserted, i.e., pressed into the inner circumferential surface of the hole 32a of the housing 32 while generating frictional force (second press-fitting). At the same time, the lower end of the shaft 33 is inserted into the hole 32a of the housing 32, and then inserted, i.e., pressed into the inner circumferential surface of the inner ring of the first radial ball bearing 31 while generating frictional force. At this time, the vibrator 35 is operated. By this vibration, ultrasonic vibration is applied to the first radial ball bearing 31, the second radial ball bearing 31a, the housing 32, and the shaft 33 via the lower jig 34 during the press-fitting (second press-fitting).

[0041] 21, the first radial ball bearing 31 and the second radial ball bearing 31a, in which the outer ring is inserted and held in the housing 32 and the shaft 33 is inserted in the inner ring, can be removed. This work is a press-fit molded product as shown in FIGS. 22, 23 and 24.

[0042] The manufacturing method of the press-fitted molded product of the third embodiment is summarized below. The shaft 33 is press-fitted into the annular portion of the inner ring of the first ball bearing 31, and the second press-fitting of the outer ring of the second ball bearing 31a into the housing 32 can be performed simultaneously with the press-fitting operation. During the press-fitting and second press-fitting, vibration is applied to the shaft 33 and / or the housing 32 and / or the first ball bearing 31 and / or the second ball bearing 31a.

[0043] (Major Effects Obtained by the Present Embodiment) In the manufacturing method of the press-fitted molded product of the first, second and third embodiments of the present invention, the vibrators 14, 24 and 35 are operated during the press-fitting and / or second press-fitting. This vibration generates ultrasonic vibration. The ultrasonic vibration suppresses the occurrence of variations in the press-fitting state that occur during the press-fitting and / or second press-fitting. For example, during the press-fitting and / or second press-fitting, a gap may occur between the press-fitting side and the pressed-in side. Even if such a gap occurs, the gap is eliminated by applying ultrasonic vibration. As a result, it is possible to reduce the variation in dimensional accuracy to the order of microns.

[0044] The application of ultrasonic vibrations as described above is one example of a means for enabling the assembly of press-fit molded products with a tolerance smaller than the elastic displacement of members (shafts, housings, bearings, etc.) or tools (jigs, equipment, etc.) Other examples include a means for applying vibrations other than ultrasonic vibrations to members and / or tools to enable the assembly of press-fit molded products with a tolerance smaller than the elastic displacement of the members or tools.

[0045] (Other forms) The above-mentioned first, second and third embodiments of the method for manufacturing the pressed molded product are examples of preferred embodiments of the present invention, but the present invention is not limited to these and various modifications are possible within the scope that does not change the gist of the present invention.

[0046] For example, in the manufacturing method of the press-fitted molded article according to the first, second and third embodiments of the present invention, ultrasonic vibration is used. However, vibration other than ultrasonic vibration, for example vibration in a frequency band different from ultrasonic vibration, may be used. For example, vibration generated by rotating an eccentric weight with a motor may be used.

[0047] In the first embodiment of the method for producing a pressed-in molded product, the ultrasonic vibration is applied at the time of pressing. However, the vibration may be applied at a time other than pressing. In the first embodiment of the method for producing a pressed-in molded product, the ultrasonic vibration is applied to the radial ball bearing 12 and the shaft 11 via the lower jig 13. However, the ultrasonic vibration may be applied to the radial ball bearing 12 or the shaft 11. When the radial ball bearing 12 and the shaft 11 are brought into close contact with each other by the force of pressing, applying vibration to one of them will propagate the vibration to the other, which is the same as applying vibration to both of them.

[0048] In the manufacturing method of the second press-fitted product of this embodiment, the timing of applying ultrasonic vibration is during press-fitting and during the second press-fitting. However, vibration may be applied at times other than during press-fitting and the second press-fitting. In the manufacturing method of the second press-fitted product of this embodiment, ultrasonic vibration is applied to the radial ball bearing 21 and the housing 22 via the lower jig 23. However, ultrasonic vibration may be applied to the radial ball bearing 21 or the housing 22. When the radial ball bearing 21 and the housing 22 are in close contact with each other due to the force of press-fitting, applying vibration to one of them will propagate the vibration to the other, which is the same as applying vibration to both of them.

[0049] In the third embodiment of the method for producing a press-fitted product, the ultrasonic vibration is applied at the time of press-fitting and the time of the second press-fitting. However, the vibration may be applied at times other than the time of press-fitting and the time of the second press-fitting. In the third embodiment of the method for producing a press-fitted product, the ultrasonic vibration is applied to the first radial ball bearing 31, the second radial ball bearing 31a, the housing 32, and the shaft 33 through the lower jig 34. However, the ultrasonic vibration may be applied to the first radial ball bearing 31 and / or the second radial ball bearing 31a and / or the housing 32 and / or the shaft 33. When the first radial ball bearing 31, the second radial ball bearing 31a, the housing 32, and the shaft 33 are brought into close contact by the force of the press-in, applying vibration to one, two, or three (any one) of them will transmit the vibration to the others, which is the same as applying vibration to all of them.

[0050] In addition, in the manufacturing method of the press-fitted molded product according to the first, second and third embodiments of the present invention, radial ball bearings are used as the ball bearings, but other types of ball bearings may be used. For example, roller bearings may be used.

[0051] In addition, the manufacturing method of the press-fitted product of the first, second and third embodiments of the present invention is not limited to a method for obtaining a workpiece including a ball bearing. For example, the manufacturing method of the press-fitted product may be a method for press-fitting a shaft or a housing into an annular portion of an annular elastic packing. During the press-fitting, vibration may be applied to the shaft and / or the elastic packing (oil seal, etc.).

[0052] Furthermore, as a modified example of this embodiment, there is provided a step of pressing the shaft into the annular portion of the inner ring of the ball bearing, and / or a second pressing step of pressing the housing into the outer ring of the ball bearing, in which a thrust load is applied to the ball bearing to create a step between the inner ring pressing surface and the outer ring pressing surface, making it possible to assemble the components and / or tools with a tolerance smaller than the amount of elastic displacement during pressing.

[0053] Here, Fig. 25 is a diagram showing a modified example of this embodiment, which corresponds to the enlarged view of the upper jig 30 and its vicinity in Figs. 19 and 20. The reference numerals used in Figs. 19 and 20 and also in Fig. 25 indicate parts having the same or very similar functions, and detailed explanations thereof will be omitted. An end of a shaft 33 is inserted into a recess 30b of the upper jig 30, and the upper surface of the recess 30b serves as a shaft pressing surface 30c. A first radial ball bearing 31 is press-fitted onto the peripheral surface of the shaft 33.

[0054] The inner ring pressing surface 30d of the first radial ball bearing 31 presses downward more strongly than the outer ring pressing surface 30e (intentionally applying a load). As a result, a step is formed between the inner ring pressing surface 30d and the outer ring pressing surface 30e, and this step (preload amount A) becomes a fixed position preload. The preload is intended to increase the precision and / or rigidity of the bearing. Note that this modification has been described based on the manufacturing method of the press-fitted molded product of the third embodiment, but it can also be applied to the modifications of the manufacturing methods of the press-fitted molded products of the first and second embodiments.

[0055] Also, the manufacturing method of the press-fitted product of the second and third embodiments of the present invention may include a second press-fitting step of press-fitting the housings 22, 32 into the outer rings of the radial ball bearing 21, the first radial ball bearing 31, and the second radial ball bearing 31b, as shown in Figures 26 and 27, and the inner peripheral surfaces of the housings 22, 32 may be free of steps 22c, 32c, 32d, allowing assembly with a tolerance smaller than the elastic displacement of the members or tools. Note that the reference numerals in Figure 27, which are also used in Figure 26, indicate parts having the same or very similar functions, and detailed explanations thereof will be omitted.

[0056] By adopting such a manufacturing method for a press-fitted product, the manufacturing methods for a press-fitted product of the second and third embodiments of the present invention use a housing 32f that does not require the formation of steps 22c, 32c, and 32d, and therefore costs can be reduced. This housing 32f has a simple cylindrical shape, and its inner peripheral surface fastens the outer ring of the radial ball bearing 31. Note that although Figures 26 and 27 show the manufacturing method for a press-fitted product of the third embodiment of the present invention, the configuration using the housing 32f can also be applied to the manufacturing method for a press-fitted product of the second embodiment of the present invention. [Explanation of symbols]

[0057] 11,33 Shaft 12,21 Radial ball bearing (ball bearing) 22,32 Housing 30d Inner ring pressing surface 30e Outer ring pressing surface 31 First radial ball bearing (first ball bearing) 31a Second radial ball bearing (second ball bearing)

Claims

[Claim 1] A method for producing a press-molded product including a first ball bearing, a second ball bearing, a housing, and a shaft, comprising: The shaft is press-fitted into an annular portion of an inner ring of the first ball bearing; a second press-fitting is performed simultaneously with the press-fitting operation, into the housing in which at least a portion of the first ball bearing is accommodated, into an outer ring of the second ball bearing; During the press-fitting and the second press-fitting, vibration is applied to the shaft, the housing, the first ball bearing, and the second ball bearing to suppress occurrence of variations in the press-fitting state that occur during the press-fitting and / or the second press-fitting, thereby assembling a press-fitted product. Manufacturing method for pressed molded products.

Images