JP2011190906A - Disc for brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the stability of the shape of a disc for a brake during the casting, and also increase a machinability during the preliminary machining of a disk outer peripheral member. <P>SOLUTION: This disc 30 for a brake includes a disc center part 31 connected to a wheel hub 14 supporting a wheel, and the disc outer peripheral member 32 formed around the disc center part 31. The disc outer peripheral member 32 includes an outer peripheral ring part 47 serving as the sliding surface of the brake, a plurality of connection parts 48 radially projecting from the inner periphery 51 of the outer peripheral ring part 47, and an inner peripheral ring part 49 formed on the inside of the outer peripheral ring part 47 so as to continuously join the distal ends of the connection parts 48. The disc center part 31 includes an enveloped casting part 41 formed at an outer diameter 41a larger than the inner diameter (inner periphery) 49c of the inner peripheral ring part 49 so as to hold, from both sides, the side surface of the inner peripheral ring part 49. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brake disc that is connected to a wheel hub to which a wheel is attached and is attached to an axle side together with the wheel hub.

The brake disc includes a disc central portion attached to the wheel hub and a disc outer peripheral member formed around the disc central portion.
The central part of the disk is formed of a light alloy such as aluminum. Also, a screw hole for mounting to the wheel hub and a through hole through which a hole mounting bolt passes are formed. The disk outer peripheral material is a portion formed of cast iron. Furthermore, it is a disc that becomes a sliding part of the brake, and protrudes in the radial direction from the inner periphery to connect to a plurality of cavities or grooves penetrated in the radial direction of the disk for heat dissipation and the central part of the disk And a plurality of connected portions.

  According to this brake disc, the center portion of the disc is formed of a light alloy such as aluminum, so that the weight can be reduced (see, for example, Patent Document 1).

Special table 2008-518175 gazette

  Here, in the brake disc of Patent Document 1, when the disc central portion is formed of a light alloy such as aluminum, the connection portion of the disc outer peripheral member formed in advance by cast iron is cast, and the disc central portion and the disc outer peripheral member are obtained. Is manufactured integrally. That is, it is desirable to reduce the thermal strain during cooling after casting because the structure is such that a plurality of connecting portions are cast at different locations in the center of the disk.

  When the connecting portion of the disk outer peripheral member is formed in a rectangular shape in cross section as in the brake disc of Patent Document 1, the machine is generally mounted on the four side surfaces of the tip portion of the connecting portion cast in the center of the disc. It was necessary to perform processing (cutting). For this reason, it took time for machining, which is a preliminary processing of the disk peripheral material.

  In addition, the central portion of the disk is made of a light alloy such as aluminum, and the outer periphery of the disk is made of cast iron. In this structure, the coefficients of thermal expansion of the disk central portion and the disk outer peripheral material are different. Therefore, consideration at the time of thermal expansion is necessary.

  It is an object of the present invention to provide a brake disc that can improve the stability of the shape of the brake disc during casting and can improve the machinability at the time of preliminary processing of the outer periphery of the disc. It is another object of the present invention to provide a brake disc that can secure the coupling strength between the disc central portion and the disc outer peripheral member and can be reduced in weight. It is another object of the present invention to provide a brake disk capable of reducing sliding resistance during thermal expansion of a disk central portion and a disk outer peripheral material formed of different materials.

  According to a first aspect of the present invention, there is provided a brake disc comprising: a disc central portion connected to a wheel hub to which a wheel is attached; and a disc outer peripheral member formed around the disc central portion. The outer ring portion that is a sliding surface of the brake, a plurality of connecting portions projecting radially from the inner periphery of the outer ring portion, and the outer ring portion so as to continuously connect the tips of these connecting portions An inner ring part formed on the inner side of the inner ring part, and a cast hole part formed so as to sandwich the side surface of the inner ring part from both sides with an outer diameter larger than the inner diameter of the inner ring part at the center of the disk It is provided with.

  The invention according to claim 2 is characterized in that the inner peripheral ring portion is provided with a plurality of protrusions protruding from the cast-in portion.

  The invention according to claim 3 is characterized in that the plurality of protrusions are formed in a larger number than the plurality of connection portions.

  The invention according to claim 4 is characterized in that the plurality of protrusions are tapered toward the tip.

The present invention has the following effects.
In the invention according to claim 1, the brake disc includes a disc central portion connected to a wheel hub to which a wheel is attached, and a disc outer peripheral member formed around the disc central portion.
To the outer periphery of the disc, the outer ring part that becomes the sliding surface of the brake, the plurality of connection parts protruding radially from the inner periphery of the outer ring part, and the tips of these connection parts are continuously connected An inner ring part formed on the inner side of the outer ring part, and formed so that the side surface of the inner ring part is sandwiched from both sides with an outer diameter larger than the inner diameter of the inner ring part in the center of the disk Since the cast-in part is provided, thermal distortion hardly occurs during cooling of the cast-in part after casting. Thereby, the shape stability of the brake disc can be improved during casting. Further, since the portion where the disk outer peripheral material is cast is the inner ring portion formed continuously, only the both side surfaces (two surfaces) of the inner ring portion may be preliminarily processed (cutting). As a result, the machinability at the time of preliminary processing is also improved.

  In the invention according to claim 2, since the inner peripheral ring portion is provided with a plurality of protrusions protruding from the cast-in portion, it is possible to sufficiently secure the coupling strength between the disc central portion and the disc outer peripheral material. In addition, since the inner ring portion is provided with a plurality of protrusions protruding from the cast-in portion, the protrusions are cut simultaneously when the inner ring portion is pre-processed (cutting), so Workability (cutability) is further improved.

  In the invention according to claim 3, since the plurality of protrusions are formed in a larger number than the plurality of connection portions, for example, the number of connection portions is increased in order to ensure the coupling strength between the disc center portion and the disc outer peripheral material. However, the brake disc can be lightened. That is, it is possible to improve the reliability by securing the coupling strength between the disc central portion and the disc outer peripheral material, and to reduce the weight of the brake disc.

  In the invention according to claim 4, since the plurality of protrusions are tapered toward the tip, the sliding resistance at the time of thermal expansion of the disc center portion and the disc outer peripheral material formed of a different material is reduced. Can do.

1 is an exploded perspective view of a disc brake device employing a brake disc according to the present invention. It is a perspective view of the disc for brakes concerning the present invention. FIG. 3 is a front view of the brake disc shown in FIG. 2. FIG. 4 is a sectional view taken along line 4-4 of FIG. 3. FIG. 3 is a perspective view showing a parting line of the brake disc shown in FIG. 2. It is a comparative examination figure of the disk for brakes concerning the present invention. It is a comparison examination figure of the parting line of the disc for brakes concerning the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

  As shown in FIG. 1, the disc brake device 10 is attached to an axle 13 and supports a wheel (not shown), and a wheel hub 14 that is attached to the wheel hub 14 and supported on the axle 13 side. This device is mainly composed of a disc 30 and a brake caliper 15 that is attached to the vehicle body 11 side and fastens the brake disc 30.

The axle 13 is formed with a spline 17 into which the wheel hub 14 is fitted. The wheel hub 14 is formed with a spline 18 that fits to the axle 13, a plurality of wheel mounting bolts 21 for mounting a wheel (not shown) are screwed in, and a plurality of screw holes 22 for mounting a brake disk 30 are opened. It has been. Further, the wheel hub 14 is fastened to the male screw portion 25 of the axle 13 with a nut 26.
The brake disc 30 is fixed to the wheel hub 14 with bolts 23.

  As shown in FIGS. 2 to 5, the brake disc 30 includes a disc central portion 31 connected to a wheel hub 14 to which a wheel is attached, and a disc outer peripheral member 32 formed around the disc central portion 31. . The brake disc 30 is integrally formed by casting the disc outer peripheral material 32 at the disc central portion 31.

  The disc central portion 31 is a substantially bon-shaped member composed of a bottom portion 34 and a cylindrical portion 35. The bottom 34 is formed with a bolt through hole 36 through which the wheel mounting bolt 21 passes, a stop hole 37 through which the bolt 23 for fixing to the wheel hub 14, and an axle through hole 38 facing the axle 13. Is done. The cylindrical portion 35 is formed such that the cylindrical surfaces (side surfaces) 49a and 49b of the inner peripheral ring portion 49 are sandwiched from both sides with an outer diameter 41a larger than the inner diameter 49c of the inner peripheral ring portion 49 of the disk outer peripheral member 32. A rounded portion 41 is formed.

  The cast-in part 41 is formed with a groove bottom 42 formed in the cylindrical part 35, and a front collar part 43 and a back collar part 44 protruding from the groove bottom 42 in the radial direction.

  The disc outer peripheral member 32 includes an outer peripheral ring portion 47 serving as a sliding surface of the brake, a plurality of connection portions 48 projecting radially from an inner periphery 51 of the outer peripheral ring portion 47, and tips of these connection portions 48. An inner ring portion 49 formed inside the outer ring portion 47 so as to be continuously connected.

The outer peripheral ring portion 47 is formed of an iron-based material. Specifically, it is formed of cast iron by casting or the like.
The outer peripheral ring portion 47 is provided with a plurality of ventilating holes (cavities) 53 penetrating from the inner periphery (inner side) 51 to the outer periphery (outer side) 52 along the radial direction of the ring. Specifically, the ventilating hole 53 is partitioned by a plurality of first to sixth ribs 54 to 59 having different lengths and shapes.

  The first rib 54 is formed wide at the inner periphery 51 of the ring, and a connecting portion 48 is formed at the tip. The second rib 55 is the shortest rib that is stopped before the inner periphery 51 of the ring. The third rib 56 is a rib formed from the outer periphery 52 to the inner periphery 51 of the ring. The fourth rib 57 is a rib that is stopped before the inner periphery 51 of the ring, and is longer than the second rib 55. The fifth rib 58 is the same rib as the third rib 56. The sixth rib 59 is the same rib as the second rib 55.

  The inner ring portion 49 is formed on the inner circumference (inner diameter) 49c between a plurality of first protrusions 61 formed coaxially with the connection portion 48 in the radial direction of the ring, and between the first protrusions 61 and 61. And a plurality of second protrusions 62. The protrusions 61 and 62 are tapered toward the center of the ring when viewed from the front. These first and second protrusions 61 and 62 have the same shape.

  The tip portions 61 c and 62 c of the first and second protrusions 61 and 62 are cast on the groove bottom 42 of the cast-in portion 41. The front and back end portions 61a, 61b, 62a, 62b of the first and second protrusions 61, 62 are cast by the front flange portion 43 and the back flange portion 44 of the cast-in portion 41, respectively.

The cylindrical surfaces 49a and 49b on the front and back of the inner peripheral ring portion 49 are cut. At this time, the front and back ends 61a, 61b, 62a, 62b of the first and second protrusions 61, 62 are also cut at the same time. This cutting is performed in two strokes on the front and back cylindrical surfaces 49a and 49b with a lathe or the like. That is, the cylindrical surface 49a is continuously processed in one stroke, and then the back cylindrical surface 49b is continuously processed in one stroke.
The front and back cylindrical surfaces 49a and 49b of the inner peripheral ring portion 49 are casted by the front and back flange portions 43 and 44 of the cast-in portion 41, respectively.

  As described above, the brake disk 30 is integrally formed by casting the disk outer peripheral material 32 at the disk center portion 31. That is, the disk outer peripheral member (sliding part) 32 has a double ring structure of an outer peripheral ring part 47 and an inner peripheral ring part 49, and the inner peripheral ring part 49 is cast by an aluminum hat-shaped disk central part 31. Join. At this time, only the cylindrical surfaces 49a and 49b (two surfaces parallel to the sliding surfaces 47a and 47b of the brake) on the front and back of the inner peripheral ring portion 49 cast by the cast-in portion 41 are processed.

  In the brake disk 30, two parting lines 64 a and 64 b can be selected as shown in FIG. 5. That is, a parting line 64a of a die (casting die) when casting the outer peripheral member 32 of the disc at the disc central portion 31 is set to the cylindrical surface 49a in the table of the inner peripheral ring portion 49 (see FIG. 3). . Alternatively, the parting line 64b is set on the cylindrical surface 49b on the back of the inner peripheral ring portion 49 (see FIG. 3).

  As a result, the parting line 64a or the parting line 64b is simplified, the precision of the cast-in mold (not shown) is improved, the processing precision of the cast-in part 41 of the disk central part 31, and the disk central part 31 is cast. It is possible to simplify the position accuracy management when mounting on the round mold. As a result, the component accuracy of the brake disk 30 is improved and the cost of the brake disk 30 is reduced.

  The disc central portion 31 is formed of aluminum or an aluminum alloy, and the disc outer peripheral member 32 is formed of an iron material such as cast iron. The linear expansion coefficient is different between aluminum or an aluminum alloy and an iron material such as cast iron (aluminum> iron). Therefore, a minute gap remains between the two after casting, and the expansion of the disk outer circumferential member 32 in the radial direction is allowed. Therefore, the brake disk 30 can be prevented from falling (surface distortion) due to the expansion of the disk outer peripheral member 32 during braking.

  Further, since the plurality of protrusions 61 and 62 are tapered toward the tip, it is possible to reduce the sliding resistance during thermal expansion of the disc central portion 31 and the disc outer peripheral member 32 made of different materials. it can.

  6 (a), 6 (b) and 7 (a) show the brake disc 100 of the comparative example, and FIGS. 6 (c) and 7 (b) show the brake disc 30 of the embodiment.

  As shown in FIGS. 6A and 6B, the brake disc 100 of the comparative example casts a plurality of connection portions 103 formed on the disc outer peripheral material 102 at the disc central portion 101, and integrally. It is formed. The plurality of connection portions 103 are convex portions having a rectangular cross section that protrude from the inner periphery (inner side) 104 of the disk outer peripheral member 102.

  In general, in order to cast a plurality of connection portions 103 at the disk center portion 101, it is necessary to individually perform machining (machining) on the four surfaces 103a to 103d of the connection portion 103, which requires time and cost for cutting. Cost. The disc central portion 101 is made of an aluminum material, and the disc outer peripheral material 102 is made of an iron material.

  In addition, as shown in FIG. 7A, the brake disc 100 of the comparative example has a parting line 106 of the cast-in-metal mold along the outer periphery 105 of the disc central portion 101 at the central portion of the connecting portion 103. Are formed. For this reason, the parting line 106 is provided in a concavo-convex shape, leading to an increase in the cost of the cast-in mold.

  As shown in FIG. 6C, the brake disk 30 of the embodiment has a configuration in which the inner peripheral ring portion 49 is cast, so that the cutting (machining) is performed with a lathe or the like. The two surfaces of the front and back cylindrical surfaces 49a and 49b may be continuously performed. Therefore, the machinability is good. Further, as shown in FIG. 7B, the parting line 64a or the parting line 64b of the cast-in mold is formed in a straight line along the cylindrical portion 35 of the disc central portion 31. The cast-in mold can be simplified.

  As shown in FIGS. 1 to 5, in the brake disc 30, the disc outer peripheral member 32 includes an outer peripheral ring portion 47 that becomes the sliding surfaces 47 a and 47 b of the brake, and an inner periphery 51 of the outer peripheral ring portion 47. A plurality of connecting portions 48 projecting in the radial direction, and an inner peripheral ring portion 49 formed inside the outer peripheral ring portion 47 so as to continuously connect the tips of these connecting portions 48, Since the part 31 is provided with the cast-in part 41 formed so as to sandwich the side surface of the inner peripheral ring part 49 from both sides with an outer diameter 41a larger than the inner diameter (inner circumference) 49c of the inner peripheral ring part 49. Thermal distortion hardly occurs during cooling of the portion 41 after casting. Thereby, the shape stability of the brake disc 30 can be improved during casting. Further, since the portion where the disk outer peripheral member 32 is cast is the continuously formed inner ring portion 49, only two sides of the inner ring portion 49 (front and back cylindrical surfaces) 49a and 49b are reserved. What is necessary is just to process (cutting). As a result, the machinability at the time of preliminary processing is also improved.

  In the brake disk 30, the inner peripheral ring portion 49 includes a plurality of protrusions 61 and 62 that protrude from the cast-in portion 41, so that the coupling strength between the disc central portion 31 and the disc outer peripheral member 32 is sufficiently ensured. Can do. Further, since the inner peripheral ring portion 49 is provided with a plurality of protrusions 61 and 62 that protrude from the cast-in portion 41, the protrusions 61 and 62 are used when the inner peripheral ring portion 49 is preliminarily processed (cutting). Since the cutting is performed at the same time, the workability (cutability) of the disk outer peripheral member 32 is further improved.

  Since the plurality of protrusions 61 and 62 are formed in a larger number than the plurality of connection portions 48, for example, in order to ensure the coupling strength between the disk center portion 31 and the disk outer peripheral member 32, the number of connection portions 48 is increased. The brake disc 30 can be reduced in weight. That is, it is possible to improve the reliability by securing the coupling strength between the disc central portion 31 and the disc outer peripheral member 32 and to reduce the weight of the brake disc 30.

  As shown in FIG. 4, the brake disk according to the present invention includes a first projection 61 formed coaxially with the connection portion 48 in the radial direction of the ring, and the first projections 61, 61 between each other. However, the present invention is not limited to this, and the projections may be formed regardless of the position of the connection portion 48, and the number of projections may be any number. It may be.

  The brake disc according to the present invention is suitable for use in passenger cars such as sedans and wagons.

  DESCRIPTION OF SYMBOLS 14 ... Wheel hub, 30 ... Brake disc, 31 ... Disc center part, 32 ... Disc outer peripheral material, 41 ... Cast-in part, 41a ... Outer diameter, 47 ... Outer ring part, 47a, 47b ... Sliding surface, 48 ... Connection part 49 ... Inner ring part 49a, 49b ... Both side surfaces (front and back cylindrical surfaces), 49c ... Inner diameter (inner circumference), 51 ... Inner circumference, 61, 62 ... Protrusions (first and second protrusions) .

Claims (4)

In a brake disc including a disc central portion connected to a wheel hub to which a wheel is attached, and a disc outer peripheral member formed around the disc central portion,
The disk outer peripheral material continuously connects the outer ring part serving as a sliding surface of the brake, a plurality of connection parts protruding radially from the inner periphery of the outer ring part, and the tips of these connection parts. And an inner ring part formed inside the outer ring part,
The brake disc according to claim 1, wherein the central portion of the disc includes a cast-in portion formed so as to sandwich a side surface of the inner peripheral ring portion from both sides with an outer diameter larger than an inner diameter of the inner peripheral ring portion.   The brake disk according to claim 1, wherein the inner ring portion includes a plurality of protrusions that protrude from the cast-in portion.   The brake disk according to claim 2, wherein the plurality of protrusions are formed in a larger number than the plurality of connection portions.   The brake disk according to claim 2, wherein the plurality of protrusions are tapered toward the tip.

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