JP2008256004A - Manufacturing method for drawn cup and shell-type needle roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a drawn cup which is reduced in the manufacturing costs. <P>SOLUTION: The manufacturing method for the drawn cup having a track plane in an annular inside-diameter surface contains the process (S11) of obtaining a cup-like member out of a flat plane by drawing, the process (S12) of forming a circumferential groove in an outer bottom wall of the cup-like member, and the process (S13) of obtaining the drawn cup by punching the bottom wall of the cup-like member by the punching process as an origin for a corner of the circumferential groove. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a shell outer ring with reduced manufacturing steps, and a shell needle roller bearing that employs a shell outer ring manufactured by such a method.

  A conventional shell needle roller bearing is described in, for example, Japanese Patent Application Laid-Open No. 2002-295485 (Patent Document 1). The shell-type needle roller bearing described in the publication maintains a space between a cylindrical shell outer ring, a plurality of needle rollers arranged along the inner diameter surface of the shell outer ring, and adjacent needle rollers. A retainer.

With reference to FIG. 6, the conventional manufacturing process of the shell outer ring | wheel employ | adopted as a shell type needle roller bearing like the said structure is demonstrated. First, in the first step, the cup-shaped member 101 is obtained from a flat plate by drawing. Next, in the second step, a through hole 103 is provided in the bottom wall 102 of the cup-shaped member 101 by punching. Next, in the third step, the through-hole 103 is expanded by turning, that is, a radially outer portion (shaded portion in FIG. 6) of the through-hole 103 is scraped off to form an annular shell outer ring. obtain.
JP 2002-295485 A

  According to the above method, two different types of processing steps, ie, punching (pressing) and turning, are required as the step of removing the bottom wall 102. This causes an increase in the processing cost of the shell outer ring. Specifically, an increase in work man-hours such as moving the cup-shaped member 101 from a punching machine to a turning machine, and an increase in a defect rate such as a scratch on the cup-shaped member 101 during the movement, and the like.

On the other hand, punching and the like as another method of removing a bottom wall 102, the diameter _{D 1} of the finished product through hole 103 is larger than the diameter _{D 2} of the inner side wall of the cup-shaped member 101 _{(D 1>} D 2) So processing is very difficult. Further, if it is attempted to remove the force, the inner wall of the cup-shaped member 101 serving as the raceway surface may be damaged.

  Furthermore, as another method for manufacturing the shell outer ring, a method of cutting a pipe material that matches the diameter of the shell outer ring in advance to a predetermined length is conceivable. However, according to this method, the material cost becomes very high, which is against the demand for reducing the manufacturing cost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a shell outer ring with reduced manufacturing costs, and a shell needle roller bearing that employs such a shell outer ring.

  The present invention relates to a method for manufacturing a shell outer ring having a raceway surface on an annular inner diameter surface. Specifically, a step of obtaining a cup-shaped member from a flat plate by drawing, a step of forming a circumferential groove on the outer bottom wall of the cup-shaped member, and a cup based on the corner of the circumferential groove by punching Punching the bottom wall of the member to obtain a shell outer ring.

  According to the above manufacturing method, stress concentration occurs in the corners of the circumferential groove in the punching process, so that the bottom wall can be punched at the intended position. Further, since the turning process can be eliminated from the process of removing the bottom wall, the manufacturing cost can be reduced.

  In the present specification, the “outer bottom wall” refers to the bottom wall surface outside the cup-shaped member. Similarly, the “inner bottom wall” refers to the bottom wall surface inside the cup-shaped component. Furthermore, the “bottom wall” refers to the entire bottom portion of the cup-shaped member including the inner bottom wall and the outer bottom wall. The same applies to the terms “side wall”, “inner side wall”, and “outer wall”.

  Preferably, the diameter at the corner of the circumferential groove is larger than the diameter of the inner wall of the cup-shaped member. In the method for manufacturing the shell outer ring, the bottom wall is removed using the stress concentration generated at the corner of the circumferential groove. Therefore, by changing the position of the corner, the bottom wall and the side wall can be connected at an arbitrary position. Can be separated. That is, the present invention is particularly effective when removing a bottom wall larger than the diameter of the inner wall.

  More preferably, an escape portion is formed at the connecting portion between the inner wall and the inner bottom wall of the cup-shaped member so as to reduce the thickness dimension of the side wall. There is a possibility that the inner side wall in the vicinity of the punched portion swells radially inward with the processing. This can cause rotation failure of the needle rollers and the cage. Therefore, these problems can be solved by reducing the thickness dimension of this portion in advance.

  A shell needle roller bearing according to the present invention includes a shell outer ring manufactured by the above-described manufacturing method, and a plurality of needle rollers arranged along the inner diameter surface of the shell outer ring. By manufacturing the shell outer ring by the above-described process, an inexpensive shell-type needle roller bearing can be obtained.

  According to the present invention, by simplifying the process of removing the bottom wall of the cup-shaped member, the manufacturing method of the shell outer ring with reduced manufacturing cost, and the inexpensive shell type employing the shell outer ring manufactured by such a method. A needle roller bearing can be obtained.

  First, with reference to FIG. 5, the shell type needle roller bearing 11 which concerns on one Embodiment of this invention is demonstrated. The shell-type needle roller bearing 11 is disposed along the raceway surface 12a on the annular inner diameter surface and the outer ring 12 having the flange portion 12b projecting radially inward at both axial ends, and along the raceway surface 12a of the outer ring 12. A plurality of needle rollers 13 and a retainer 14 that holds the interval between the adjacent needle rollers 13.

  Next, with reference to FIGS. 1-4, the manufacturing method of the shell outer ring | wheel 12 which concerns on one Embodiment of this invention is demonstrated. 1 is a flowchart showing a part of the manufacturing process of the shell outer ring 12, FIG. 2 is a view showing the cup-shaped member 21 after the drawing process, and FIG. 3 is a cup-shaped member 21 after the circumferential groove forming process. FIG. 4 is a view showing the cup-shaped member 21 after the bottom wall 23 is punched. 2 to 4 depict the plate thickness larger than the actual thickness in order to facilitate understanding of the invention.

  First, the shell outer ring 12 employs, as a starting material, a flat plate obtained by rolling carbon steel such as bearing steel. The content of an element such as carbon is adjusted so as to satisfy mechanical properties such as hardness, toughness, wear resistance, and workability required for the shell outer ring 12.

  Next, in the first step, the cup-shaped member 21 is obtained from the flat plate by drawing (S11). Referring to FIG. 2, cup-shaped member 21 has a cylindrical side wall 22 and a bottom wall 23 that closes one end portion (the lower side in FIG. 2) of side wall 22. The inner wall 22a functions as a raceway surface 12a that contacts the needle rollers 13. Therefore, the drawing depth (referring to “the height of the side wall 22”) needs to be set deeper than the length of the needle rollers 13. In addition, an escape portion 24 is provided at a connection portion between the inner side wall 22a and the inner bottom wall 23a so as to reduce the thickness dimension of the side wall 22. The escape portion 24 is a circumferential groove continuous in the circumferential direction.

  In this drawing process (S11), the inner wall 22a having a predetermined length may be obtained by one drawing process, or the drawing process may be repeated a plurality of times. Further, by repeating the drawing process a plurality of times, a portion thinner than the normal plate thickness (hereinafter referred to as “thin portion”) is concentrated on the connecting portion between the inner wall 22a and the inner bottom wall 23a, and the relief portion 24 is formed. The

  Further, after the drawing step (S11), ironing processing for smoothing the inner wall 22a that becomes the raceway surface 12a, trimming processing for trimming the other end (upper side in FIG. 2) of the side wall 22, and the side wall 22 An edge bending process or the like for forming the flange 12b is applied to the other end portion of the rim.

  Next, in the second step, the circumferential groove 25 is formed in the outer bottom wall 23b of the cup-shaped member 21 (S12). Specifically, it can be formed by press working such as coining (coining). The circumferential groove 25 has a V-shaped cross section. The diameter of the circumferential groove 25 at the corner 25a (pointing to the root portion) is set to be larger than the diameter of the inner wall 22a.

  Next, in the third step, the bottom wall 23 is removed by punching (S13). Specifically, the cup-shaped member 21 is placed on a cylindrical die with the outer bottom wall 23b facing downward, and the punch is placed on the inner bottom wall 23a in the same direction as the drawing direction (downward direction in FIG. 3). Apply a load to Thereby, stress concentration occurs in the corner portion 25 a of the circumferential groove 25, and the bottom wall 23 is separated from the cup-shaped member 21. And the shell outer ring | wheel 12 is obtained.

  Here, the corner | angular part 25a of the circumferential groove 25 becomes a base point of a fracture | rupture in the punching process (S13) of the bottom wall 23. FIG. That is, if the position of the corner portion 25a is changed, the side wall 22 and the low wall 23 can be separated at an arbitrary position. That is, the present invention is particularly effective when removing the bottom wall 23 larger than the diameter of the inner wall 22a.

  Next, in the fourth step, the shell outer ring 12 is subjected to heat treatment in order to obtain predetermined mechanical properties (S14). Specific examples of heat treatment include bright quenching, carburizing quenching, or carbonitriding for the purpose of improving hardness, wear resistance, etc., and tempering and annealing for the purpose of improving toughness and removing residual stress. And so on.

  The shell outer ring 12 is obtained through the above steps. Here, in the manufacturing method according to the present invention, the drawing step (S11), the circumferential groove 25 forming step (S12), and the bottom wall 23 punching step (S13) are all press working steps. Therefore, if the shape of the punch and the die and the magnitude of the stress applied to the cup-shaped member 21 are adjusted, it can be processed by the same processing machine.

  That is, if the manufacturing method according to the present invention is employed, it is not necessary to move the cup-shaped member 21 for each processing step, and therefore the number of work steps associated with the movement can be reduced. Further, by omitting the movement of the cup-shaped member 21, it is possible to prevent the occurrence of scratches associated with the movement of the cup-shaped member 21, which has been a problem in the past. As a result, the manufacturing cost of the shell outer ring 12 can be reduced, and an inexpensive shell needle roller bearing 11 can be obtained.

  In the punching process (S13) of the bottom wall 23, the side wall 22 is deformed at a position close to the bottom wall 23. Specifically, the inner wall 22a is deformed so as to rise in the radial direction. Therefore, in order to prevent the deformation of the needle rollers 13 and the cage 14 from being hindered by this deformation, it is desirable to provide an escape portion 24 in a portion that may be deformed in advance.

  In the above embodiment, the sectional shape of the relief portion 24 is an arc shape having a predetermined curvature. However, the sectional shape is not limited to this and may be an arbitrary sectional shape. However, it is desirable to have a curved surface shape so that stress concentration does not occur when the bottom wall 23 is punched.

  On the other hand, in the circumferential groove 25, the stress concentration generated in the corner portion 25a increases as the V-shaped angle decreases. Therefore, it is desirable that the V-shaped angle is an acute angle from the viewpoint of ease of punching. On the other hand, if the V-shaped angle is too small, it becomes difficult to form the circumferential groove 25. Therefore, it is necessary to select an appropriate V-shaped angle from these viewpoints.

  Moreover, although the cross-sectional shape showed the V-shaped example for the circumferential groove | channel 25 in said embodiment, it is not restricted to this, Arbitrary shapes are employable. However, it is necessary to have the corners 25a so as to cause stress concentration in the punching process (S13) of the bottom wall 23.

  Moreover, although the shell type needle roller bearing 11 in said embodiment showed the example which has the holder | retainer 14 as a component, the holder | retainer 14 is not an essential component in this invention. That is, the present invention can also be applied to a full-roller type shell needle roller bearing.

  Moreover, each said process is an example of the manufacturing process of the shell outer ring | wheel 12 which concerns on this invention, Comprising: Each process may be further subdivided and a required process can also be added further. The order of the processing steps can be arbitrarily changed.

  Furthermore, each of the above steps may be performed by a single press as a separate step, but may be performed by a progressive press or a transfer press. Thereby, each process can be performed continuously. Moreover, by using the manufacturing apparatus of the shell outer ring | wheel 12 which has the process part corresponded to all or one part of said each process, productivity can be improved and, as a result, the product price of the shell type needle roller bearing 11 Can be suppressed.

  In the present specification, “sequential press” refers to a method of continuously processing a material by having a plurality of processing steps in the press and moving the material by a feeder at a press inlet. Shall. In addition, in this specification, “transfer press” means that when a plurality of processing steps are required, the necessary number of stages for performing each step are provided, and processing is performed at each stage while moving the process product by the transfer device. Refers to the method of performing

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used for shell-type needle roller bearings.

It is a flowchart which shows a part of manufacturing process of the shell outer ring | wheel which concerns on one Embodiment of this invention. It is a figure which shows the cup-shaped member obtained by drawing. It is a figure which shows the state which formed the circumferential groove | channel in the outer bottom wall of a cup-shaped member. It is a figure which shows the state which removed the bottom wall of the cup-shaped member. It is a figure which shows the shell type needle roller bearing which concerns on one Embodiment of this invention. It is a figure which shows a part of manufacturing process of the conventional shell outer ring | wheel.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Shell type needle roller bearing, 12 Shell outer ring, 12a Raceway surface, 12b collar part, 13 Needle roller, 14 Cage, 21,101 Cup-shaped member, 22 Side wall, 22a Inner side wall, 23,102 Bottom wall, 23a Inner bottom wall, 23b Outer bottom wall, 24 relief part, 25 circumferential groove, 25a corner part, 103 through hole.

Claims (4)

A method for manufacturing a shell outer ring having a raceway surface on an annular inner diameter surface,
Obtaining a cup-shaped member from a flat plate by drawing;
Forming a circumferential groove in the outer bottom wall of the cup-shaped member;
And a step of punching a bottom wall of the cup-shaped member from a corner of the circumferential groove as a base point to obtain the shell outer ring by punching.   2. The method for manufacturing a shell outer ring according to claim 1, wherein a diameter of the circumferential groove at the corner is larger than a diameter of an inner wall of the cup-shaped member.   3. The method for manufacturing a shell outer ring according to claim 1, wherein a relief portion is formed at a connection portion between the inner wall and the inner bottom wall of the cup-shaped member so as to reduce a thickness dimension of the side wall. A shell outer ring manufactured by the method for manufacturing a shell outer ring according to any one of claims 1 to 3,
A shell-type needle roller bearing comprising a plurality of needle rollers arranged along a raceway surface of the shell outer ring.

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