JPH0158779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to disc brakes, and more particularly to disc brakes that include a thermal balancing mass in a rotor or disc. The heat mass is
It acts as a heat sink to counterbalance the heat sink provided by the support mounting structure used to secure the rotor or disk to the wheel hub.

The frictional heating and heat dissipation functions of disc brakes in vehicles are accurately depicted in a cyclical manner. The brakes are applied intermittently and occasionally to bring the vehicle to a stop, and this repeated use creates significant intervals for the frictional heating parts to cool. The solid disc brake assembly is a substantial, usable heat sink to which heat generated along the walls of the disc is transferred by frictional engagement with the brake pads. While the inner edge of the disk has a substantially adjacent support structure that provides a significant heat sink, the outer edge of the disk has no corresponding or compensatory heat sink, creating a radial temperature gradient across the disk.

Of course, long-term use of disc brakes generates a large amount of heat, which can be better dissipated by incorporating a plurality of radially arranged ventilation passages into the disc or rotor. (The term "brake disk" here generally refers to both solid and vented brake rotor assemblies; however, the term "disc" refers only to solid assemblies and the term "rotor" refers to vented assemblies. This distinction is explained below.) For general purposes, the disc will be referred to as a solid rotor, and the brake will follow as it is commonly referred to as a disc brake.The radial passages provide an additional heat transfer surface and air circulation within the rotor. Vented rotors generally dissipate heat into the surrounding air more quickly than solid disks due to their large heat transfer surface and air circulation. The inner and outer walls of the rotor are separate thermal assemblies that are separated by a plurality of radial ribs or webs and are therefore subjected to different thermal environments.Furthermore, the rotor hub and/or mounting structure typically It is fixed to at least one of the walls and provides a substantial thermal mass or heat sink, thus also creating a radial thermal temperature gradient in the wall adjacent or connected to the mounting support structure.

The present invention relates to a novel brake rotor or disc that provides a thermally balanced assembly to act as a heat sink, compensating the assembly and thus the heat sink essentially provided by the rotor or disc mounting structure. As will become clear below, the balanced assembly is cast integrally with or secured to the rotor or disc at any step of the manufacturing process by suitable fastening means. Furthermore, the material of the balance assembly may be, but need not be, the material of the disk or rotor itself. For example, when considering space, materials with high heat capacity (specific heat) are used. In other cases, lightweight materials are desirable. Modifications such as balancing the heat sink assembly of the rotor or disk support structure are also within the scope of the invention.

In ventilated rotors, the counterbalancing assembly is arranged on the rotor wall closest to the support means, generally the outer wall, so that the thickness of the outer wall increases with increasing radial length from the rotor center. In still other embodiments, the heat sink assembly is disposed along the rotor wall to provide the desired heat sink balance and reduce radial temperature gradients.

Furthermore, the vented rotor or solid disk includes agglomerates or materials in the peripheral area where the brake pads do not act. To do this, the area of frictional engagement between the brake pads and the rotor or disk wall is reduced by reducing the radial width of the pads, thus freeing them from engagement with the outer circumference of the rotor or disk, which acts as a heat sink. Additional material may be added around the disk to form an annular body or in any desired shape. The distribution (ie, cross-section) of the circumferential mass is adjusted to suit specific spatial and thermal equilibrium conditions.

It is therefore an object of the invention to provide a brake or disc with a small radial temperature gradient.

Another object of the present invention is to provide a ventilated brake rotor with a low radial temperature gradient, which is manufactured by conventional conventional manufacturing methods.

Other objects and advantages of the invention will become apparent to those skilled in the art from the following description and drawings.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 10 is a disc brake assembly according to the present invention. The disc brake assembly 10 includes a caliper assembly 12 and a rotor assembly 14. The rotor assembly 14 includes generally planar parallel outer and inner walls 18, respectively.
20. Rotor assembly 14 further includes a truncated head portion 22 that is typically cast integrally with rotor portion 16 . The support structure or lid 22 defines a plurality of apertures 24, which a plurality of ear bolts 26 of the wheel hub 28.
The rotor assembly 14 is secured to the wheel hub 28 in the conventional manner in conjunction with other members. The support structure of the rotor portion 16 as well as the means for connecting it to the wheel hub 28 may take many forms and may be manufactured by a variety of manufacturing methods in addition to those illustrated. For example, the support structure may consist of a planar inward extension of the rotor or disk, which disk may include a longitudinally grooved mating member, a special insert or a special insert secured to the rotor or disk by suitable fastening means, including monolithic casting. , a cross section for mounting around the disk or rotor is mounted axially slidably on the spindle or axle by a U-shaped structure. The present invention can be implemented by the above-described mounting method and other mounting forms.

1 and 2, the caliper assembly 12 is generally C-shaped and has a caliper bridge 30 interconnecting an outer leg 32 and an inner leg 34. In FIGS. This carrier public body 30 is the rotor part 1
6 and is positioned and held by a guide (not shown) disposed parallel to the axis of the rotor assembly 14 and fixed to the retaining plate 35. These guides float mount the caliper assembly 12 by conventional disc brake means. A cylinder 36 is formed in the inner leg 34 of the caliper assembly 12, and a mating piston 38 is disposed within the cylinder. According to conventional procedures, pressurized fluid is supplied to cylinder 36 to advance piston 38 toward rotor section 16 . cylinder 36
An annular groove 40 is provided adjacent to the mouth of the holder, in which an annular seal member 42 is seated. This annular seal member 42 is preferably made of an elastic material such as rubber to prevent loss of pressure fluid from the cylinder 36. The piston 38 has an annular groove 44 which serves as a retainer for a complementary shaped portion of the dust boot 46. Dust boot 46 has an integral one-piece seal molded from a resilient material such as rubber. The folded bellows dust boot 46 provides a protective seal around the piston 38 to the caliper assembly 12 while permitting substantially relative axial movement therebetween. The outer disc brake pad assembly 48 and the inner disc brake pad assembly 50 are slidably disposed on the retaining plate 35 and are in sliding contact with the outer wall 18 and inner wall 20 of the rotor section 16.

As will become clear below, the foregoing description is merely indicative of the components associated with the caliper, as the present invention is not directed to the caliper assembly 12 and related parts thereof. The present invention is well implemented in motive energy sources such as pneumatic, mechanical or electrical devices, as well as in highly modified caliper assemblies and piston geometries. Furthermore, the structure and function of the caliper assembly 12 and its related parts are conventional and well understood by those in the disc brake art;
These will not be discussed further.

Next, referring to FIGS. 2 and 3, the rotor portion 16 has an outer wall 18 and an inner wall 20, as described above. The rotor section 16 is vented and itself includes a plurality of ribs 56 as well as a plurality of radial passages 54.
and these ribs form the outer wall 18 of the rotor portion 16.
and the inner wall 20. According to the invention,
The inner wall 20, and more generally the wall portion remote from the mounting structure or lid portion 22 and bounded therefrom by ribs 56, has a uniform thickness. However, the thickness of the outer wall 18, and more generally the wall of the rotor section 16 that is most closely connected to the mount or lid 22, increases with distance from the center of the rotor assembly 14. The wedge shape of the outer wall 18 is in thermal equilibrium with the lid 22, thereby reducing radial temperature gradients across the outer wall 18 of the rotor section 16.

Furthermore, in Fig. 2, especially in Fig. 3,
As the thickness of the outer wall 18 increases, the width of the air passage 54 decreases. Given that the inlet and outlet lengths of the passageway 54 are equal, such a reduction in the width of the passageway 54 makes the outlet smaller and closes or prevents airflow within the passageway 54. Of course, such air flow blockage can be eliminated by making the area of the air passage outlet approximately equal to or larger than the area of the air passage inlet. By adjusting the cross-sectional area of the ribs 56, the air passageway can be maintained at a substantially constant or radially increasing cross-sectional area. Therefore, both the heat sink of the mounting structure can be thermally balanced and the air flow in the radial air passages can be well maintained.

Next, in FIG. 4, another embodiment of the rotor 60 is shown.

Here, the modified rotor 60 has an inner wall 62 having a constant thickness at its thinnest portion and an outer wall 64 whose thickness increases outwardly.
and has. The rotor 60 has an air passage 66 that is generally oblong in cross section. The main axis of the elongated oval passage 66 is disposed circumferentially around the rotor 60 . The main axis of the elongated oval passage 66 on the inner surface of the rotor 60 is parallel to the axis of the rotor 60, and therefore the rotor 60
It is perpendicular to the principal axis of the elongated passageway 66 on the outer surface of the elliptical passageway 66 . Note that even with such a shape, the air passage in addition to the heat sink body has a constant or radially increasing cross-sectional area, and the radial temperature gradient of the wall of the rotor 60 adjacent to the mounting structure is reduced. On the other hand, the air flow within the elongated oval passage 66 is maintained well.

Furthermore, neither the uniformly tapered wall of the rotor and its generally rectangular air passageway according to embodiments adjacent to the lid nor the fan-shaped notched tapered wall and generally elongated air passageway of the modified rotor shall be construed as limiting the scope of the invention. Must not be. Rather, any rotor wall configuration that includes a heat sinking body to balance the mass and a heat sinking effect of the rotor mounting structure to reduce radial temperature gradients within the rotor is considered to be within the scope of the present invention.

FIG. 5 illustrates the thermal equilibrium achieved by providing an assembly in the wall of a vented brake rotor to counterbalance the inherent heat sink provided by the rotor mounting structure and thus reduce the radial temperature gradient within the rotor. This is another example. It should be noted that the following calculations are illustrative and explanatory, and are only intended to further clarify and explain the present invention. The accuracy of the results is proportional to the apparent complexity of the mathematical analysis. The results are approximate and can be improved by more complex mathematical and empirical analysis as well as experimental tests such as dynamometric tests.

FIG. 5 shows an outer rotor wall and lid similar to those used in heavy duty vehicle brakes. The ribs and inner walls of the rotor are shown in dashed lines for reference only and are not included in the calculations below, as their heat transfer and temperature gradient characteristics are similar to the radial heat transfer of the rotor wall adjacent to the mounting structure. This is because the influence on temperature gradient characteristics can be ignored. As described, elements 1, 2, and 3 of the rotor lid shown in FIG.
It acts as a heat sink for the frictional heat generated and absorbed by the surface of the adjacent outer wall of the rotor. Element 5 in FIG. 5 is a tapered assembly disposed in the rotor wall, which, together with the assembly of element 4, counterbalances the heat sink provided by elements 1, 2 and 3 of the lid.

The calculations below quantify this equilibrium relationship and establish the approximate width or thickness of the triangular element 5 for fixed dimensions of the lid and rotor elements 1, 2, 3 and 4, respectively. The radii and other dimensions of the elements in the lid and rotor are shown in FIG. According to Patsposu's theorem, it states that the volume of a rotating solid is the product of the generated area and the length traveled by the locus of the center of the area.Using this theorem, we can calculate the volumes of various elements, and therefore the density of the rotor. and specific heat are assumed to be constant, so the mass and heat capacity of these elements are calculated.

For lid element 1, the area (A ₁ ) is equal to 0.5 inches by 2.4 inches, or A ₁ = 1.2 square inches, and the center trajectory radius (Y ₁ ) is equal to 1.5 inches + 1.2 inches, or Y ₁ = 2.7 inches, and the length of travel due to the center trajectory (D ₁ ) is 5.4π inches. According to Patspos' theorem, the product A ₁ D ₁ is equal to the volume of element 1 (V ₁ ), and A ₁ D ₁ is 6.46π cubic inches.
Similarly, for element 2, the area (A ₂ ) is 0.5 inches by 2.0 inches, or A ₂ = 1.0 square inches, and the center trajectory radius (Y ₂ ) is equal to 3.9 inches + 0.25 inches, or Y ₂ = 4.15 inches. The length of movement by the center trajectory (D ₂ ) is 8.3π inches. product
A ₂ D ₂ is equal to the volume of element 2 (V ₂ ), 8.3π cubic inches. Also, in element 3, the area (A ₃ ) is 0.5 inches x 1.2 inches, or A ₃ = 0.6
square inch, center locus radius (Y ₃ ) is 3.9 inches +
0.6 inches, or Y ₃ =4.5 inches, and the length of travel by the center trajectory (D ₃ ) is 9.0π inches. product
A ₃ D ₃ is the volume of element 3 (V ₃ ). Equal to 5.4π cubic inches. Finally elements 1, 2 and 3
The total volume (and proportional mass) of (V ₁₂₃ ) is equal to ΣAD, or 6.48π cubic inches + 8.3π cubic inches + 5.4π cubic inches = 30.18π cubic inches.

Performing these same calculations for elements 4 and 5 in the rotor section, the area of element 4 (A ₄ ) is 0.5 inches x
2.6 inches, or A ₄ = 1.3 square inches, the center trajectory radius Y ₄ is equal to 5.1 inches + 1.3 inches, or Y ₄ = 6.4 inches, and the length of travel by center trajectory D ₄ is 12.8π inches. The product A ₄ D ₄ is equal to 16.6π cubic inches. Similarly, in element 5, area (A ₅ )
is equal to 0.5 x 2.6 inches x T, or A ₅ =
1.3T inch, center locus radius Y ₅ is 5.1 inch + 0.667
×2.6 inches, or Y ₅ =6.8 inches, and the length of movement by the center trajectory D ₅ is 13.6π inches. The volume of element 5 (V ₅ ) is equal to the product A ₅ D ₅ or 17.7πT cubic inches.

To obtain static thermal equilibrium, the volumes (and masses) of elements 1, 2, and 3 are approximated to the volumes (and masses) of elements 4 and 5. That is, V ₁ +V ₂ +V ₃ V ₄ +V ₅ 20.18π cubic inches 16.6π cubic inches + 17.7πT cubic inches 3.56π cubic inches 17.7πT cubic inches 0.2 inches T Therefore, the maximum of the triangular element 5 of the rotor section of 0.2 inches The large range is a first approximation of the thickness at which thermal equilibrium is achieved for a rotor assembly of the above dimensions.

The above description of the preferred and variant embodiments has been made for a ventilated rotor having generally radially oriented air passages between the walls of the brake rotor. However, the inventive concept of providing an assembly on the brake rotor to compensate for the inherent heat sinking characteristics of the mounting structure is also applicable to solid brake discs. Thus, the present invention provides a solid disk with a specially configured circumferential extension, or only one side of the disk close to the mounting groove structure, or at least a peripheral zone that does not come into sliding contact with the entire side wall of the disk and does not come into contact with the brake pads. Includes a brake disc with sections on both sides. With such a configuration, this area of the disc is not a heat source in frictional contact with the brake pad, but only serves as an additional mass that acts as a heat sink and compensates for the inherent heat sink properties of the mounting structure.

6, 7, 8 and 9 illustrate four solid disk configurations that may be used in the practice of the present invention. More specifically, FIG. 6 shows a solid disc 70 secured to a monolithic lid 72. As shown in FIG.
The frictionally engaging portion of the disc 70 corresponding to the effective radial width of the brake pad (not shown) is designated by the bracket 74. It is clear that the disc 70 extends beyond this engagement area. To explain further, the outer edge of the disk 70 is formed obliquely, forming a sharp triangular portion 76 around the outer edge. The triangular section 76, with most of the assembly adjacent to the closest side of the lid to the disk 70, provides a slightly larger heat sink on this rotor side than on the opposite side to thermally balance the disk 70.

Similarly, FIG. 7 shows the lid portion 82 and the engaging rotor surface 84.
In addition, a disk 80 according to an embodiment is shown. An aggregate is arranged on the disk 80. In a manner similar to the solid disk embodiment shown in FIG. Get a bigger heatsink.

By nature, a solid disk tends to have a more uniform temperature than a ventilated rotor, so it is applicable when the thermal balancing mass is uniformly applied around the disk. Furthermore, when a mounting structure, such as the radially extending planar structure described above, is fixed approximately symmetrically about the axially intermediate surface of the disk, this structure is generally optimally balanced. In FIG. 8, the solid brake disc 90 has an integral flat mounting portion 9 as described above.
2 is formed. Also, the frictional engagement area of the disk 90 is indicated by a bracket 94. Rings 96, which are generally rectangular in cross-section, are uniformly distributed around the disk 90. This annulus 96 may be cast together or subsequently secured to the disk 90 and may be made of the same or a different material as the disk 90. In addition, since the material is evenly distributed around the axially intermediate surface of the disk 90, the aggregate of the annular bodies 96 acts fairly uniformly as a heat sink on the left and right surfaces of the solid disk 90, like the flat mounting portion 92. fulfill a function.

FIG. 9 shows a third embodiment of a solid disk 100 with an assembly around its periphery to thermally equilibrate the inherent heat sink forming the monolithic lid 102. FIG. In this embodiment, the additional assembly is formed in the triangular section 104 and the annulus 96 of the second embodiment shown in FIG.
Similarly, heat is uniformly absorbed and dissipated from both the left and right sides of the disk 100. Additional assemblies incorporated into either the solid disk or the ventilated rotor are therefore disposed around the rotor in a manner consistent with the purpose of thermally balancing the inherent heat sink provided by the rotor's mounting structure. Once the predetermined thermal equilibrium heat transfer characteristics are established, the specific material, heat capacity, mass, cross-section, or thickness is determined based on casting, manufacturing technology, cost, or energy reserves, etc. considerations.

As previously mentioned, the inventive concept can also be practiced by reducing the amount of surface on one side of the disk or rotor that is adjacent to the mounting structure, or on both sides of the disk or rotor that the brake pads frictionally engage. In summary, FIG. 9 shows a conventional brake butt engagement surface 106 on the right side. On the opposite side of the disk 100, a small frictional engagement area 10
8 is used to practice the invention, since the disengaged area 110 effectively acts as a heat sink rather than a source of frictional heat. It should be noted that by reducing the radial width and thus the area of frictional engagement of both left and right brake pads, heat sinks can be provided on both sides of the brake disc or rotor.

The above disclosure is the best mode devised by the inventors for carrying out the present invention. However, modifications and variations to the present invention will be apparent to those skilled in the art of disc brakes. The foregoing disclosure is intended to enable any person skilled in the art to practice the invention, and it is intended that the invention not be limited thereto, but that the invention be interpreted to include such obvious modifications, and is intended to be interpreted within the spirit and scope of the claims. should be limited only to

[Brief explanation of drawings]

FIG. 1 is a perspective view of a disc brake and ventilated rotor using the present invention, and FIG. 2 is a line 2--2 of FIG. 1.
FIG. 3 is a partial perspective view of a vented brake rotor according to the invention showing the radial air passages; FIG. 4 is an assembly according to another embodiment; FIG. 5 is a partial perspective view of a vented disc brake rotor according to the present invention showing distribution and radial passages; FIG. 5 is a cross-sectional diagram of a portion of a vented brake rotor illustrating the general heat transfer theory of the present invention; FIG. 7 is a partial cross-sectional view of another embodiment of a solid brake disk incorporating the present invention, and FIG. 8 is a partial cross-sectional view of another embodiment of the solid brake disk incorporating the present invention. FIG. 9 is a partial cross-sectional view of a solid brake disc incorporating a third modification of the present invention. 10... Disc brake assembly, 12
...Caliper assembly, 14...Rotor assembly, 16,60...Rotor section, 18,64...
Outer wall, 20, 62... Inner wall, 22, 72, 82,
102...lid part, 32...outer leg, 34...inner leg,
36...Cylinder, 38...Piston, 40,4
4... Annular groove, 42... Seal member, 48...
Outer disc brake pad assembly, 50...
...Inner disc brake pad assembly, 5
4,66...Aisle, 56...Rib, 70,80,
90,100...Disk.

Claims (1)

[Scope of Claims] 1. A combination of a rotor assembly having an axis, a caliper assembly having a pair of brake pads, and a device operably linked to the pads to advance the pads into frictional contact with the rotor assembly. and wherein the rotor assembly includes a rotor portion and a centrally disposed lid portion, the portion of the rotor portion that does not engage a brake pad that is spaced radially outwardly of the rotor from the lid portion; A disc brake assembly comprising: a heat sink member disposed in thermal equilibrium with the heat sink provided by the lid portion to reduce a temperature gradient in the radial direction of the rotor portion. 2. The disc brake assembly according to claim 1, wherein the rotor portion is solid, and the heat sink member is disposed on the outer periphery of the rotor portion. 3. A disc brake assembly according to claim 2, wherein a cross section of said portion parallel to the rotor axis is substantially triangular. 4. A disc brake assembly as claimed in claim 2, wherein said section has a generally rectangular cross section parallel to the rotor axis. 5. The rotor assembly includes first and second spaced apart circular walls and an air passageway radially disposed therein, the heat sink member extending from opposite inner surfaces of the walls. at least one of
2. A disc brake assembly as claimed in claim 1, wherein the disc brake assembly is located along a road. 6. The disc brake assembly of claim 5, wherein the axial thickness of the heat sink member increases with increasing distance from the axis. 7. The rotor according to claim 6, further comprising a plurality of rib members interconnecting the first wall body and the second wall body, the cross section of the rib member being substantially uniform along the radial length of the rotor. Disc brake assembly as shown.