WO2020139191A1

WO2020139191A1 - Brake disc

Info

Publication number: WO2020139191A1
Application number: PCT/SG2018/050638
Authority: WO
Inventors: Wey Chin TAN; Nicholas Kian Tiong TAN
Original assignee: Sunstar Singapore Pte., Ltd.
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2020-07-02
Also published as: GB2590338B; JP2021513030A; GB202104279D0; JP6941167B2; GB2590338A

Abstract

A brake disc includes a hub component intended to be fixed to a wheel, a rotor component with which brake pads can be engaged, a coupling constituent for coupling the hub component and the rotor component together, and the hub component is provided with a plurality of hub recesses and the rotor component is provided with a plurality of rotor recesses. The coupling constituent limits relative circumferential movement between the hub component and the rotor component, and allows free relative axial movement between the hub component and the rotor component within a predetermined distance from 0.3 mm to 0.7 mm. The centre of a hub-side circle which includes the hub recess is located further radially inside than the centre of a rotor circle which includes the rotor recess. Occurrence of brake judder is reduced and the durability of the biasing device is improved.

Description

BRAKE DISC

TECHNICAL FIELD

The invention relates to brake discs, and more specifically, to floating brake discs for motorcycles.

BACKGROUND ART

Conventional floating brake discs for motor cycles relate to the technology disclosed in the Patent Literatures 1 and 2 mentioned below. A floating brake disc according to the related art includes a hub component intended to be fixed to a wheel; a rotor component with which brake pads can be engaged, the rotor component being coupled to the radially outer side of the hub component so as to be concentric with the hub component; and a coupling pin for coupling the hub component and the rotor component together. The coupling pin is inserted in a coupling hole which is formed by the hub component and the rotor component in combination. The end portions of the coupling pin have a large diameter, which prevents the coupling pin from coming out of the coupling hole. The hub component and the rotor component are thus fixed together by the coupling pin.

As illustrated in Fig. 7, the floating brake disc according to the related art includes a spring washer intervening between either one of the large-diameter portions at the ends of the coupling pin and a plate surface of the hub component/rotor component, to thereby limit relative axial movement between the hub component and the rotor component.

Due to the limited relative axial movement between the hub component and the rotor component, when the brake is applied, the brake disc is limited from moving to be positioned with respect to the brake pads pressing the brake disc. This might cause brake judder and deteriorate brake performance.

The related art disclosed in the Patent Literature 1 includes a biasing device for biasing the rotor component away from the hub component. The biasing device is, for example, an omega spring. The omega spring is accommodated on the hub component side of the coupling hole so as to receive one side of the coupling pin, to thereby limit relative rotational movement of the rotor component with respect to the hub component.

When the brake is applied, however, the rotor component intends to make relative rotational movement with respect to the hub component, which causes a part of the omega spring to be wedged between the edge of the coupling hole on the hub component side and the coupling pin. If this occurs very often, a problem will occur in durability of the omega spring.

CITATION LIST PATENT LITERATURE PTL 1: EP3203103A1

PTL 2: Japanese Utility Model Registration No. 2569319

SUMMARY OF INVENTION TECHNICAL PROBLEM

The invention has been made in light of the facts described above. An object of the invention is to improve the brake performance by further reducing the occurrence of brake judder.

Another object of the invention is to improve the durability of the biasing device. SOLUTION TO PROBLEM

To solve the foregoing problem, a brake disc of the invention comprises a hub component intended to be fixed to a wheel; a rotor component with which brake pads can be engaged, the rotor component being coupled to a radially outer side of the hub component so as to be concentric with the hub component; and a coupling constituent for coupling the hub component and the rotor component together, the coupling constituent being configured to limit relative circumferential movement between the hub component and the rotor component and allow free relative axial movement between the hub component and the rotor component within predetermined distance.

Preferably, the hub component is provided with a plurality of hub recesses along an outer circumference of the hub component, and the rotor component is provided with a plurality of rotor recesses along an inner circumference of the rotor component. The hub recesses and the respective rotor recesses are opposed in pairs to form a plurality of coupling holes. The coupling constituent comprises a rivet pin. The rivet pin includes a body which passes through the coupling hole, and first and second large-diameter portions formed in relative end portions of the body. The first and second large-diameter portions are larger in diameter than the coupling hole. A gap of the predetermined distance which allows the free relative axial movement is formed between an axially inner surface of the first large-diameter portion and each of opposed surfaces of the hub component and the rotor component, the opposed surfaces being opposed to the axially inner surface of the first large-diameter portion. Preferably, the predetermined distance is within a range from 0.3 mm inclusive to 0.7 mm inclusive.

The coupling constituent according to another aspect of the invention further includes a biasing device for biasing the rivet pin away from the hub component side toward the rotor component side. The biasing device includes a middle portion accommodated in the hub recess so as to receive one side of the body of the rivet pin, and first and second strips extending from the middle portion to their respective ends of the biasing device. The first and second strips are inserted in their respective radial gaps between the hub component and the rotor component to limit the relative circumferential movement between the hub component and the rotor component.

Preferably, the hub recesses are larger in radius than the rotor recesses, and the center of a hub-side circle which includes the hub recess as a partial circle of the hub-side circle is located further radially inside than the center of a rotor circle which includes the rotor recess as a partial circle of the rotor circle. For example, the biasing device is an omega spring.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a plan view of a brake disc according to one embodiment of the invention.

Fig. 2 is a plan view of a rotor component included in the brake disc illustrated in

Fig. 1. Fig. 3 is a plan view of a hub component included in the brake disc illustrated in Fig.

1.

Fig. 4 is a partial sectional view taken along line A— A on the brake disc of Fig. 1.

Fig 5 is an enlarged sectional view of a coupling constituent illustrated in Fig. 4, which is configured to couple the rotor component and the hub component together.

Fig. 6 is a plain view of the coupling constituent illustrated in Fig. 5.

Fig. 7 is an enlarged sectional view of a coupling pin according to related art.

DESCRIPTION OF EMBODIMENTS

One embodiment of the invention will be discussed below with reference to the attached drawings.

Fig. 1 shows a brake disc 1 according to the one embodiment of the invention. As illustrated in Fig. 1, the brake disc 1 comprises a rotor component 2 with which brake pads, not shown, can be engaged, and a hub component 3 intended to be fixed to a wheel of a motorcycle, not shown. The rotor component 2 is coupled to a radially outer side of the hub component 3 so as to be concentric with the hub component 3 with O as a common center. The hub component 3 and the rotor component 2 are coupled together by a plurality of coupling constituents 5 circumferentially arranged at regular intervals.

The rotor component 2 is provided with a number of punched holes 7 for reducing the weight and inertial moment of the brake disc 1. Formed between every two adjacent coupling constituents 5 is a punched hole 8 for reducing the weight and inertia moment of the brake disc 1.

The hub component 3 is provided with a central opening 10. Fixing holes 6 are formed around the central opening 10 at regular intervals. Bolts or the like are inserted in the fixing holes 6 to fix the brake disc 1 to the wheel of the motorcycle. The fixing holes 6 may be properly altered in number and arrangement according to the wheel of the motorcycle to which the brake disc 1 is fixed. A plurality of punched holes 9 are formed radially outside the fixing holes 6. A punched hole 11 is formed between every two adjacent fixing holes 6. Fig. 2 shows the rotor component 2 as a single body. As illustrated, rotor recesses 12a are formed along an inner circumference of the rotor component 2 at places where the coupling constituents 5 are formed in the brake disc 1. A virtual circle 15 includes the rotor recess 12a as a partial circle. The circle 15 has center 13 and diameter 2rl. A radial distance between the center 13 of the circle 15 and the center O is defined as Rl. 8a represents a rotor- side portion of the punched hole 8.

Fig. 3 shows the hub component as a single body. As illustrated, hub recesses 12b are formed along an outer circumference of the hub component 3 at places where the coupling constituents 5 are formed in the brake disc 1. A virtual circle 16 includes the hub recess 12b as a partial circle. The circle 16 has center 14 and diameter 2r2. A radial distance between the center 14 of the circle 16 and the center O is defined as R2. 8b represents a hub-side portion of the punched hole 8.

Fig. 4 is a sectional view of the brake disc 1, which shows a portion including the coupling constituent 5. As illustrated in Fig. 4, the rotor recesses 12a and the hub recesses 12b are opposed in pairs, to thereby form coupling holes 12. Rivet pins 5a forming the coupling constituents 5 are inserted in the coupling holes 12, to thereby couple the rotor component 2 and the hub component 3.

Fig. 5 shows in detail a configuration of the rivet pin 5a. As illustrated in Fig. 5, the rivet pin 5a includes a body 20 which passes through the coupling hole 12, and a first large-diameter portion 21 and a second large-diameter portion 22 which are formed in their respective end portions of the body 20. The first large-diameter portion 21 and the second large-diameter portion 22 are larger in diameter than the coupling hole 12. The first large- diameter portion 21 is a small-diameter portion smaller in diameter than the coupling portion 12 at the point of time when the rivet pin 5a is inserted into the coupling hole 12. The first large-diameter portion 21 may be formed by swaging this small-diameter portion after the insertion of the rivet pin 5a. A gap 24 of predetermined distance which allows free relative axial movement between the hub component 3 and the rotor component 2 is formed between an axially inner surface of the first large-diameter portion 21 and each of opposed surfaces of the hub component 3 and the rotor component 2, the opposed surfaces being opposed to the axially inner surface of the first large-diameter portion 21.

When brake is applied, the gap 24 of the predetermined distance allows an axial movement of the rotor component 2 relative to the hub component 3, which enables the brake disc 1 to be positioned with respect to the brake pads pressing the brake disc 1. This improves brake performance and reduces the occurrence of brake judder.

Preferably, the predetermined distance of the gap 24 is within a range from 0.3 mm inclusive to 0.7 mm inclusive. This is because, if the predetermined distance is smaller than 0.3 mm, the movement of the rotor component 2 becomes excessively hard, which makes difficult the positioning when brake is applied. If the predetermined distance is larger than 0.7 mm, the rotor component 2 is excessively loosen. This hinders the brake disc 1 from functioning properly and further might cause a collision between the rivet pin 5a and the rotor component 2 or the hub component 3, resulting in noise generation.

The present embodiment thus does not require a spring washer. As compared to the related art illustrated in Fig. 7, the present embodiment makes it possible to cut product cost, lessen production time, and reduce testing.

According to the present embodiment, the coupling constituent 5 illustrated in Fig. 5 may include, for example, an omega spring 23 which is a biasing device for biasing the rivet pin 5a away from the hub component 3 side toward the rotor component 2 side.

As illustrated in Fig. 6, the omega spring 23 includes a middle portion 23a accommodated in the hub recess 12b so as to receive one side of the body of the rivet pin 5a, and first and second strips 23b, 23c extending from the middle portion to their respective ends of the omega spring 23. The first and second strips 23b, 23c are inserted in radial gaps 25b, 25c, respectively, between the hub component 3 and the rotor component 2, to thereby limit the relative circumferential movement between the hub component 3 and the rotor component 2.

A radius (radius r2 of the circle 16 in Fig. 3; for example, 15.2 mm/2) of the hub recess 12b is larger than a radius (radius rl of the circle 15 in Fig. 2; for example, 14 mm/2) of the rotor recess 12a. The distance R2 from the brake disc center O to the center (14 in Fig. 3) of the hub-side circle (16 in Fig. 3) including the hub recess 12b as the partial circle thereof is smaller than the distance R1 from the brake disc center O to the center (13 in Figs.

2 and 6) of the rotor-side circle (15 in Fig. 2) including the rotor recess 12a as the partial circle thereof (for example, R 1=222 mm, R2=220 mm). In other words, the center (14 in Fig. 3) of the hub-side circle (16 in Fig. 3) including the hub recess 12b as the partial circle thereof is located further radially inside than the center (13 in Figs. 2 and 6) of the rotor-side circle (15 in Fig. 2) including the rotor recess 12a as the partial circle thereof.

Due to the above-described configuration, the rivet pin 5a comes into contact with B and C points, as illustrated in Fig. 6, when located in a threshold position 26 after moving to the lower left in Fig. 6. As a result, an edge of the hub recess 12b in an area 27, the rivet pin 5a moved to the threshold position 26, and a part of the omega spring 23 are prevented from overlapping with each other at A point and thus prevented from contacting each other. The omega spring 23 is thus improved in durability.

The one embodiment of the invention has been described. The invention is not limited to the foregoing example, and may be modified in any proper way within the scope of the invention.

For example, the brake disc 1 according to the embodiment includes both the gap 24 of the predetermined distance illustrated in Fig. 5 and the device for improving the durability of the omega spring, which is accomplished by the difference in radius between the hub-side circle and the rotor-side circle and the displacement of center positions of the hub-side circle and the rotor-side circle as illustrated in Fig. 6. However, it is possible to accomplish the gap 24 and the device separately in different embodiments.

The configuration, arrangement and number of the coupling constituents 5, the shape of the omega spring 23, the shape, arrangement and number of the punched holes, and the like may be properly altered.

REFERENCE SIGN LIST

1 : Brake disc 2: Rotor component

3: Hub component

5: Coupling constituent

5a: Rivet pin

6: Fixing hole

7, 8, 9, 11: Punched hole

10: Central opening

12: Coupling hole

12a: Rotor recess

12b: Hub recess

13: Center of circle 15 (Distance from disc center O is Rl)

14: Center of circle 16 (Distance from disc center O is R2)

15: Virtual circle (with diameter 2rl) including the rotor recess 12a as its partial circle

16: Virtual circle (with diameter 2r2) including the hub recess 12b as its partial circle

20: Body of the rivet pin

21: First large-diameter portion

22: Second large-diameter portion

23: Omega spring

23a, 23b, 23c: Middle portion, and strips on the ends of the omega spring 24: Gap of predetermined distance

25b, 25c: Radial gaps between the hub component 3 and the rotor component 2

Claims

1. A brake disc comprising:

a hub component intended to be fixed to a wheel;

a rotor component with which brake pads can be engaged, the rotor component being coupled to a radially outer side of the hub component so as to be concentric with the hub component; and

a coupling constituent for coupling the hub component and the rotor component together,

the coupling constituent being configured to limit relative circumferential movement between the hub component and the rotor component and allow free relative axial movement between the hub component and the rotor component within predetermined distance.

2. The brake disc of Claim 1,

wherein the hub component is provided with a plurality of hub recesses along an outer circumference of the hub component, and the rotor component is provided with a plurality of rotor recesses along an inner circumference of the rotor component, the hub recesses and the respective rotor recesses being opposed in pairs to form a plurality of coupling holes;

wherein the coupling constituent comprises a rivet pin,

the rivet pin including a body which passes through the coupling hole, and first and second large-diameter portions formed in respective end portions of the body, the first and second large-diameter portions being larger in diameter than the coupling hole; and

wherein a gap of the predetermined distance which allows the free relative axial movement is formed between an axially inner surface of the first large-diameter portion and each of opposed surfaces of the hub component and the rotor component, the opposed surfaces being opposed to the axially inner surface of the first large-diameter portion.

3. The brake disc of Claim 2,

wherein the predetermined distance is within a range from 0.3 mm inclusive to 0.7 mm inclusive.

4. The brake disc of Claim 2 or 3,

wherein the coupling constituent further includes a biasing device for biasing the rivet pin away from the hub component side toward the rotor component side,

the biasing device including a middle portion accommodated in the hub recess so as to receive one side of the body of the rivet pin, and first and second strips extending from the middle portion to respective ends of the biasing device, the first and second strips being inserted in respective radial gaps between the hub component and the rotor component to limit the relative circumferential movement between the hub component and the rotor component.

5. The brake disc of Claim 4,

wherein the hub recesses are larger in radius than the rotor recesses, and the center of a hub-side circle which includes the hub recess as a partial circle of the hub-side circle is located further radially inside than the center of a rotor circle which includes the rotor recess as a partial circle of the rotor circle.

6. The brake disc of Claim 4 or 5,

wherein the biasing device is an omega spring.