JP3901424B2 - Brake drum for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical portion coaxially surrounding a cylindrical boss fixed to an axle, and a connecting portion integrally connected to one end of the cylindrical portion so as to connect between the boss and one end of the cylindrical portion. In particular, the present invention relates to an improvement of a brake drum for preventing brake squeal.
[0002]
[Prior art]
Conventionally, a structure in which an elastic ring is fixed to the outer periphery of the brake drum to prevent brake noise is disclosed, for example, in Japanese Utility Model Publication No. 63-193131, and a metal ring is provided on the outer periphery of the brake drum. A structure that is fixed to prevent brake squeal is also known.
[0003]
[Problems to be solved by the invention]
In the case where an elastic ring or a metal ring is fixed as in the conventional case, not only the number of parts is increased but also an assembly process of the ring is required, which causes an increase in cost.
[0004]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicular brake drum that can reduce the number of parts and the number of assembling steps while obtaining an effect of preventing noise.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that the cylindrical portion that coaxially surrounds the cylindrical boss fixed to the axle, and the cylindrical portion so as to connect between the boss and one end of the cylindrical portion. In the vehicle brake drum having a connecting portion integrally connected to one end of the portion, the cylindrical portion has a small diameter cylindrical portion having one end connected to the outer periphery of the connecting portion, and a larger diameter than the small diameter cylindrical portion. a large diameter cylindrical portion, and an inner peripheral inner circumference are formed on their small-diameter cylindrical portion and a wider且 one radially thicker in the axial direction than the radial thickness of the large diameter cylindrical portion of the small-diameter cylindrical portion Ri formed continuous with and seamlessly integrated coaxially through the annular thick portion continuous to and periphery with the same diameter are continuous with the same diameter as the outer periphery of the large diameter cylindrical portion, the thick portion and the large diameter cylinder The inner peripheral surfaces of the parts gradually expand in diameter from the thick part toward the large diameter cylindrical part. And the outer peripheral surfaces of the thick-walled portion and the small-diameter cylindrical portion are connected by a second connection surface that gradually decreases in diameter from the thick-walled portion toward the small-diameter cylindrical portion, The large-diameter cylindrical portion and the thick-walled portion are formed integrally by squeezing the inner diameter side .
[0006]
According to such a structure, the rigidity of a cylindrical part can be improved by the thick part formed in a cylindrical part, the vibration of a cylindrical part can be suppressed, and a brake squeal can be prevented. Moreover, since the thick wall portion is formed integrally with the cylindrical portion when the brake drum is molded, compared to the conventional one in which a ring, which is a separate member from the brake drum, is fixed to the outer periphery of the cylindrical portion. Thus, the number of parts can be reduced, and the assembling man-hours can be reduced by eliminating the ring assembling step.
[0007]
According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the boss is formed integrally with the connecting portion. According to such a configuration, the connecting portion of the brake drum is provided. Compared with what welds to a boss | hub, it is unnecessary to finish the inner surface of a cylindrical part after welding with a boss | hub, and can reduce a process man-hour. That is, if the connecting portion is welded to the boss, the cylindrical portion and the boss may be distorted due to heat at that time, and processing to correct the distortion is required. However, the boss and the connecting portion are integrally formed. Therefore, the occurrence of such distortion can be prevented, and the number of processing steps can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0009]
FIG. 1 and FIG. 2 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a wheel having a brake drum, and FIG. 2 is a view sequentially showing a forging process of the brake drum.
[0010]
First, in FIG. 1, the outer periphery of the spoke 3 is welded to the rim 2 to which the tire 1 is mounted, and the inner periphery of the spoke 3 is welded to the outer periphery of the brake drum 4 according to the present invention.
[0011]
The brake drum 4 integrally includes a cylindrical boss 5 fixed to the axle 9, a cylindrical portion 6 that coaxially surrounds the boss 5, and a connecting portion 7 that connects between the boss 5 and one end of the cylindrical portion 6. The cylindrical portion 6 is integrally formed with a ring-shaped thick portion 6c.
[0012]
Such a brake drum 4 is formed by forging through, for example, the process shown in FIG. 2. In the forging, a blank material 11 is first prepared as shown in FIG. As the material 11, a light metal such as an aluminum alloy or a titanium alloy, carbon steel, stainless steel, a copper alloy, or the like can be suitably used, and the shape of the blank material 11 is preferably a donut shape.
[0013]
The forging process is performed on the blank material 11 in such a manner that the steps shown in FIGS. 2B to 2G are sequentially performed. As shown, a primary molded body 12 having a bell-shaped cross section is obtained.
[0014]
The primary molded body 12 is subjected to upset processing, whereby a secondary molded body 15 having a semi-finished boss portion 13 and a semi-finished cup portion 14 is obtained, as shown in FIG. Further, the secondary molded body 15 is subjected to an overhanging process. Thereby, as shown in FIG. 2 (d), the third molded body 18 having the semi-finished boss portion 16 and the semi-finished cup portion 17 in the shape of projecting the semi-finished boss portion 13 and the semi-finished cup portion 14, respectively. Is obtained.
[0015]
The third molded body 18 is flattened on the end face of the semi-finished boss portion 16 and subjected to the squeezing process on the semi-finished cup portion 17, whereby the semi-finished boss portion 19 is formed as shown in FIG. And the 4th molded object 21 which has the semi-finished cup part 20 is obtained, and the thick part 20a is formed in the opening edge part of the semi-finished cup part 20. FIG.
[0016]
The fourth molded body 21 is subjected to a sizing process that reduces the diameter of the semi-finished boss portion 19 and squeezes the inner diameter of the semi-finished cup portion 20, thereby, as shown in FIG. 2 (f). In addition, a semi-finished product 4 ′ substantially corresponding to the brake drum 4 is obtained. This semi-finished product 4 ′ has a cylindrical boss 5, a cylindrical portion 6 that coaxially surrounds the boss 5, and a connecting portion 7 that connects between the boss 5 and one end of the cylindrical portion 6. The cylindrical portion 6 includes a small-diameter cylindrical portion 6a having one end connected to the outer periphery of the connecting portion 7, and a large-diameter cylindrical portion 6b having a larger diameter than the small-diameter cylindrical portion 6a, and the diameters of the small-diameter cylindrical portion 6a and the large-diameter cylindrical portion 6b . It is wider in the axial direction than the wall thickness in the direction and thick in the radial direction, the inner circumference is continuous with the inner diameter of the small-diameter cylindrical portion 6a, and the outer circumference is the same as the outer circumference of the large-diameter cylindrical portion 6b. The ring-shaped thick part 6c that is continuous in diameter is coaxially and seamlessly connected continuously. That is, the cylindrical portion 6 is integrally formed with the ring-shaped thick portion 6c.
[0017]
Further, as shown in FIG. 1, the inner peripheral surfaces of the thick part 6c and the large diameter cylindrical part 6b are first connection surfaces that gradually increase in diameter from the thick part 6c toward the large diameter cylindrical part 6b. In addition, the outer peripheral surfaces of the thick portion 6c and the small diameter cylindrical portion 6a are connected by a second connection surface that gradually decreases in diameter from the thick portion 6c toward the small diameter cylindrical portion 6a.
[0018]
The inner surface of the boss 5 in the semi-finished product 4 ′ is spline-molded. As a result, as shown in FIG. 2G, a spline groove 10 for connecting the axle 9 to the spline is formed on the inner periphery of the boss 5. The brake drum 4 having it is obtained.
[0019]
Next, the operation of this embodiment will be described. Since the ring-shaped thick portion 6c is integrally formed with the cylindrical portion 6 provided in the brake drum 4, the cylindrical portion 6 is increased in rigidity by the thick portion 6c. The vibration of the part 6 can be suppressed and brake noise can be prevented. In addition, since the thick portion 6c is formed integrally with the cylindrical portion 6 when the brake drum 4 is molded, a ring that is a separate member from the brake drum 4 is fixed to the outer periphery of the cylindrical portion 6. Compared to the conventional one, the number of parts can be reduced, and the assembly process can be reduced by eliminating the ring assembly process.
[0020]
Further, since the connecting portion 7 of the brake drum 4 and the boss 5 are integrally formed, the inner surface of the cylindrical portion 6 is finished after welding with the boss, as compared with the case where the connecting portion 4 of the brake drum 4 is welded to the boss. It is not necessary to reduce the number of processing steps, and the processing accuracy of the spline grooves 10 provided on the inner surface of the boss 5 can be maintained at a high level. That is, when the connecting portion 7 is welded to the boss, processing for correcting distortion generated in the cylindrical portion 6 due to welding heat at that time is required, or processing accuracy of the spline groove 10 on the inner surface of the boss 5 is lowered. However, since the boss 5 and the connecting portion 7 are integrally formed, it is not necessary to perform such processing for correcting distortion, and the number of processing steps can be reduced. The processing accuracy can be maintained at a high level.
[0021]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0022]
【The invention's effect】
As described above, according to the first aspect of the present invention, the cylindrical portion includes the small-diameter cylindrical portion having one end connected to the outer periphery of the connecting portion and the large-diameter cylindrical portion having a larger diameter than the small-diameter cylindrical portion. The cylindrical portion and the large-diameter cylindrical portion are formed to be wider in the axial direction and thicker in the radial direction than the radial thickness , and the inner circumference is the same as the inner circumference of the small-diameter cylindrical portion and the outer circumference is the larger. Concentric and seamlessly connected through a ring-shaped thick part that has the same diameter as the outer circumference of the cylindrical part. In addition, the brake squeal can be prevented, and the thick part is formed integrally with the cylindrical part when the brake drum is molded. Therefore, a ring, which is a separate member from the brake drum, is formed on the outer periphery of the cylindrical part. The number of parts can be reduced compared to the conventional ones that are supposed to be fixed. It is possible to reduce the assembling steps of assembling steps of the ring as needed.
[0023]
Further, according to the invention described in claim 2, the number of processing steps can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a wheel having a brake drum.
FIG. 2 is a diagram sequentially showing a forging process of a brake drum.
[Explanation of symbols]
4 ... Brake drum 5 ... Boss 6 ... Cylindrical part 6a ... Small diameter cylindrical part 6b ... Large diameter cylindrical part 6c ... Thick part 7 ... Connecting part 9 ... Axle

Claims (2)

A cylindrical portion (6) coaxially surrounding a cylindrical boss (5) fixed to the axle (9), and the cylindrical portion so as to connect one end of the boss (5) and the cylindrical portion (6) In the vehicle brake drum having the connecting portion (7) integrally provided at one end of (6),
The cylindrical portion (6) includes a small diameter cylindrical portion (6a) having one end connected to the outer periphery of the connecting portion (7) and a large diameter cylindrical portion (6b) having a larger diameter than the small diameter cylindrical portion (6a). The small diameter cylindrical portion (6a) and the large diameter cylindrical portion (6b) are formed so as to be wider in the axial direction and thicker in the radial direction than the thickness in the radial direction . formed continuous with and seamlessly integrated coaxially continuous to and periphery in the circumferential and the diameter through the annular thick portion contiguous with the same diameter as the outer periphery of the large diameter cylindrical portion (6b) (6c) is,
A first connection in which the inner peripheral surfaces of the thick part (6c) and the large diameter cylindrical part (6b) gradually increase in diameter from the thick part (6c) toward the large diameter cylindrical part (6b). The outer peripheral surfaces of the thick part (6c) and the small diameter cylindrical part (6a) are gradually reduced in diameter from the thick part (6c) toward the small diameter cylindrical part (6a). Connected at the second connection surface,
The brake drum for a vehicle, wherein the large-diameter cylindrical portion (6b) and the thick-walled portion (6c) are integrally formed by squeezing the inner diameter side .   The vehicle brake drum according to claim 1, wherein the boss (5) is formed integrally with the connecting portion (7).

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