Title of Invention

"INTERLOCKED BRAKE DEVICE FOR MOTOR VEHICLE"

Abstract An interlocked brake device for a motor vehicle, comprising: a master cylinder (M) being caused to work by the operation of a brake operating part (LI); a hydraulic front wheel brake (Bf) being caused to work by hydraulic pressure output from the master cylinder (M); a hydraulic actuator (A) being caused to work by the hydraulic pressure output from the mater cylinder (M); and a mechanical rear wheel brake (Br) having a working lever (25) turned by the working of the hydraulic actuator (A) through a brake cable (Cl), the interlocked brake system leaving an effective stroke necessary to cause the front wheel brake (Bf) to work both in the brake operating part (LI) and the master cylinder (M) even while the hydraulic actuator (A) is working with full stroke. Representative Fig. .. 1
Full Text The present invention relates to an interlocked brake device for a motor vehicle particularly suitable for two-wheeled motor vehicles, the interlocked brake system being designed to allow both a front wheel brake and a rear wheel brake to work simultaneously by a single brake operating part.
RELATED ART
The following two types of interlocked brake systems are known as conventional interlocked brake systems, As disclosed, e.g., in Unexamined Japanese Patent Publication No, Sho. 56-67681, a mechanical front wheel brake is mechanically interlocked with a mechanical rear wheel brake. On the other hand, as disclosed, e.g., in Unexamined Japanese Patent Publication No. Sho. 56-154378, both a hydraulic front wheel brake and a hydraulic rear wheel brake are caused to work by hydraulic pressure output from a common master cylinder.
By the way, while brake systems having a hydraulic front wheel brake and a mechanical rear wheel brake are often used for two-wheeled motor vehicles that are relatively light in weight, among these brake systems interlocked brake systems in which a hydraulic front wheel brake is interlocked
with a mechanical rear wheel brake are not found.
Thus, the following interlocked brake system would be proposed. The mechanical rear wheel brake is coupled to the brake lever of the master cylinder through a brake cable, the brake lever of the master cylinder being attached to the steering handle to cause the hydraulic front wheel brake, and the rear wheel brake is caused to work by the operation of a single brake lever. That is, the system is designed to share a single brake lever in common for both the hydraulic and mechanical brakes before the system "branches into these different types of brakes. However, in such a case, play of the brake cable affects. That is, since a play of the brake cable in the mechanical rear wheel brake system is greater than that of the brake cable in the hydraulic front wheel brake, the front wheel brake is caused to work in advance at the time the brake lever is operated, which in turn prevents both brakes from working simultaneously reliably.
SUMMARY OF THE INVENTION
The present invention has been made in view of the aforementioned circumstances. An object of the invention is therefore to provide an interlocked brake system for a motor vehicle that not only allows both a hydraulic front wheel brake and a mechanical rear wheel brake to be caused to work simultaneously by a single brake operating part, but also allows the hydraulic front wheel brake to be caused to work
reliably even if a breakage occurs in the mechanical system of the mechanical rear wheel brake.
To achieve the above object, a first feature of the present invention is that an interlocked brake system for a motor vehicle includes: a master cylinder that is caused to work by the operation of a brake operating part; a hydraulic front wheel brake that is caused to work by hydraulic pressure output from the master cylinder; a hydraulic actuator that is caused to work by the hydraulic pressure output from the master cylinder; and a mechanical rear wheel brake that has a working lever turned by the working of the hydraulic actuator through a brake cable, and that such interlocked brake system leaves an effective stroke necessary to work the front wheel brake in the brake operating part and the master cylinder even while the hydraulic actuator is working with full stroke.
In addition to the aforementioned feature, the present invention has a second feature in which a second brake operating part and the working lever are coupled through a second brake cable so that the rear wheel brake is operated also by the second brake operating part. Accordingly there is provided an interlocked brake device for a motor vehicle, comprising:
a master cylinder being caused to work by the operation of a brake operating part;
a hydraulic front wheel brake being caused to work by hydraulic pressure output from the master cylinder;
a hydraulic actuator being caused to work by the
cUva a mechanical rear wheel brake having a working lever
turned by the working of the hydraulic actuator through a brake
d «/>>»«•*-cable, the interlocked brake syslcfli leaving an effective stroke
necessary to cause the front wheel brake to work both in the brake operating part and the master cylinder even while the hydraulic actuator is working with full stroke.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS.
Fig. 1 is a side view of a motor scooter having an interlocked brake system of the present invention;
Fig. 2 is a diagram showing a steering handle; and
Fig. 3 is a system diagram showing main portions of the interlocked brake system in longitudinal cross sectional form.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of the present invention will now be described with reference to an embodiment shown in the accompanying drawings.
First, in Fig. 1, a motor scooter, which is a two-wheeled motor vehicle, has a hydraulic front wheel brake Bf for braking a front wheel Wf and a mechanical rear wheel brake Br for braking a rear wheel Wr. A first brake lever L1 for operating both brakes Bf, Br simultaneously and a second brake lever L2 for operating only the rear brake Br are arranged adjacent to a right-hand grip la and a left-hand grip 1b of a steering handle 1 of the motor scooter, respectively.
In Figs. 2 and 3, the cylinder main body 2 of a master cylinder M is attached to the steering handle 1 close to the inner end of the right-hand grip la, and the first brake lever L: is journaled 4 to a lever holder 3 that is formed integrally with the cylinder main body 2.
A piston 6 is fitted into a cylinder hole 2a of the cylinder main body 2, the piston defining a hydraulic chamber 5 with respect to the front end of the cylinder main body 2. A return spring 7 that urges the piston 6 toward the
retreating limit is accommodated in the hydraulic chamber 5. The retreating limit of the piston 6 is regulated by the retreating surface of the piston 6 coming in contact with a stopper ring 8 that is retained on the inner surface of the rear end of the cylinder hole 2a. The piston 6 has a rod portion 6a that projects from the rear end face thereof. A working arm portion 10 of the first brake lever L1 comes in contact with the end face of the rod portion 6a. The piston 6 can be driven forward through the working arm portion 10 by drawing an operating arm portion 9 of the lever L1 nearer toward the right-hand grip la of the steering handle 1.
An oil reservoir 11 that stores operating oil is integrally formed on the upper side of the cylinder main body 2. A relief port 12 and a supply port 13 are bored in a partition wall between the oil reservoir 11 and the cylinder hole 2a. The relief port 12 is located so that when the piston 6 is to be positioned to the retreating limit, the oil chamber 5 communicates with the oil reservoir 11 immediately before the piston 6 comes to the retreating limit position. Therefore, when the piston 6 is caused to advance, the piston 6 can produce hydraulic pressure with the piston 6 having moved past an ineffective stroke SN in which the front edge of the piston 6 passes over the relief port 12 forward.
An output port 14 that is continuous to the hydraulic chamber 5 is bored in the front end wall of the cylinder main body 2, and this output port 14 is connected to an input port
15 of the hydraulic front wheel brake Bf (a hydraulic disc
brake in the shown embodiment) through a hydraulic conduit
16.
A hydraulic actuator A is connected to the output port 14 of the master cylinder M or to the hydraulic conduit
16 through a branch conduit 17. The hydraulic actuator A
includes: an actuator main body 20 having a cylinder hole
20a; a piston 23 that is fitted into the cylinder hole 20a to
define the interior of the cylinder hole 20a into a hydraulic
chamber 21 and an air chamber 22;"arid" a return spring 24 that
urges the piston 23 toward the hydraulic chamber 21. The
downstream end of the branch conduit 17 is connected to an
input port 18 that is continuous to the hydraulic chamber 21
while bored in the actuator main body 20. The actuator main
body 20 is secured to a motor scooter body potion that is
extremely close to the rear wheel brake Br (to the step
portion in the shown embodiment).
The piston 23 has a piston rod 23a that passes through an end wall of the hydraulic chamber 21 fluid-tight. The front end of a first brake cable c1 is connected to the piston rod 23a through a yoke 26, and the rear end of the cable c1 is connected to a working lever 25 of the mechanical rear wheel brake Br (a mechanical drum brake in the shown embodiment).
A second brake lever L2 is coupled to the working lever 25 through a second brake cable C2. For the coupling
of the cables, it is so arranged that the coupling point of the first brake cable C1 comes nearer toward the turning center of the lever 25 than the coupling point of the second brake cable C2.
Thus, when the first brake lever L1 is turned toward the right-hand grip la of the steering handle 1 to cause the master cylinder M to work, hydraulic pressure produced in the hydraulic chamber 5 is supplied to the front wheel brake Bf and the hydraulic actuator A via the output port 14, the hydraulic conduit 16, and the branch conduit 17, and as a result, these members Bf and A are caused to work.
At this time, the hydraulic actuator A has the piston 23 thereof operated by the hydraulic pressure supplied to the hydraulic chamber 21 thereof in Fig. 3. That is, the first brake cable C1 is pulled by the piston 23, which then turns the working lever 25, so that the rear wheel brake Br works. Thus, as a result of the operation of the first brake lever L1, both the hydraulic front wheel brake Bf and the mechanical rear wheel brake Br can be caused to work simultaneously.
Since the hydraulic actuator A, in particular, is arranged at a motor scooter body fixing portion that is extremely close to the rear wheel brake Br, the first brake cable C1 connecting between the piston 23 and the working lever 25 becomes extremely short. As a result, delay in operating the rear wheel brake Br due to play of the cable
can be minimized, which in turn allows both the front and the rear brakes Bf, Br to be caused to work simultaneously reliably.
In addition, since the coupling point of the first brake cablec1 on the working lever 25 is located nearer toward the turning center of the working lever 25, the effective arm length of the lever 25 at the time of turning is relatively short. Therefore, the braking force of the rear wheel brake Br is controlled to be weaker than that of the front wheel brake Bf, which can provide a motor scooter with satisfactory braking.
In the thus constructed interlocked brake system, in order to ensure that the front wheel brake Bf will be caused to work by operating the first brake lever L1 should the first brake cable C1 be broken, the dimensions of the various parts of the master cylinder M and the hydraulic actuator A are set so that the following equation can be established. SL: effective stroke of the operating arm portion 9 of
the first brake lever L1 E: lever ratio of the first brake lever L1 (operating
arm portion 9 length / working arm portion 10 length) SM: maximum stroke of the piston 6 of the master cylinder
M SN: ineffective stroke of the piston 6 of the master
cylinder M AM: cross-sectional area of the hydraulic chamber 5 of
the master cylinder M SA: maximum stroke of the piston 23 of the hydraulic
actuator A AA: . cross-sectional area of the hydraulic chamber 21 of
the hydraulic actuator A V: quantity of operating oil of the front wheel brake Bf
(Equation Removed)
In the aforementioned equation (1), AA x SA / AM gives the effective stoke volume of the hydraulic actuator A in terms of the stroke of the piston 6 of the master cylinder M; SM - SN - v / AM gives the effective stroke of the piston 6 of the master cylinder M with the quantity of oil necessary to cause the front wheel brake to work taken into account; and SL / E gives the effective stroke of the working arm portion 10 of the first brake lever L1. Therefore, according to the aforementioned equation (1), when the mater cylinder is caused to work by operating the first brake lever Ll, even if the first brake cable C1 is broken to thereby cause the piston 23 of the hydraulic actuator A to move with full stroke, there still remains a stroke necessary and sufficient to cause the front wheel brake Bf to work in both the first
brake lever L1 and the master cylinder M. As a result, at least the front wheel brake Bf can be caused to work reliably.
Further, even if this case, when the second brake lever L2 is operated, the working lever 25 can be turned through the second brake cable C2, which in turn allows the rear wheel brake Br to be caused to work.
With respect to the effective stroke SL of the operating arm portion 9 of the first brake lever Ll, it is preferred, in practical terms, that a redundant stroke portion that is 1/3 to 1/4 the effective stroke SL remain between the operating arm portion 9 and the right-hand grip la even when the piston 23 of the hydraulic actuator A has moved with full stroke.
The invention is not limited to the aforementioned embodiment, but may be designed around in various modes as long as such design modes do not depart from the spirit and scope of the present invention. For example, the first and the second brake levers Li, L2 can be implemented in the form of foot brake pedals.
As described in the foregoing, according to the first feature of the present invention, the interlocked brake system includes: a master cylinder that is caused to work by operating a brake operating part; a hydraulic front wheel brake that is caused to work by hydraulic pressure output from the master cylinder; a hydraulic actuator that is caused
to work by the hydraulic pressure output from the master cylinder; and a mechanical rear wheel brake that has a working lever turned by the working of the hydraulic actuator through a brake cable. By arranging the hydraulic actuator, the length of the first brake cable can be reduced, which in turn contributes to reducing a delay in operating the rear wheel brake caused by play of the brake cable. Hence, when the master cylinder is caused to work by the brake operating part, the hydraulic front wheel brake and the mechanical rear wheel brake can be caused to work simultaneously reliably.
In addition, even while the hydraulic actuator is working with full stroke, the interlocked brake system leaves an effective stroke sufficient to cause the front wheel brake to work in the brake operating part and the master cylinder. Therefore, should the brake cable be broken, the front wheel brake can be caused to work reliably by the hydraulic pressure output from the master cylinder after the hydraulic actuator has moved maximum stroke as long as the master cylinder is operating.
Moreover, according to the second feature of the present invention, a second brake operating part and the working lever are coupled through a second brake cable so that the rear wheel brake is caused to work also by the second brake operating part. As a result of this construction, even if the first brake cable has broken, both the front and the rear wheel brakes can be caused to work
simultaneously by the simultaneous operation of the first and the second brake operating parts.



WE CLAIM :
1. An interlocked brake device for a motor vehicle, comprising:
a master cylinder (M) being caused to work by the operation of a brake operating part (LI);
a hydraulic front wheel brake (Bf) being caused to work by hydraulic pressure output from the master cylinder (M);
a hydraulic actuator (A) being caused to work by the hydraulic pressure output from the mater cylinder (M); characterised by
a mechanical rear wheel brake (Br) having a working lever (25) turned by the working of the hydraulic actuator (A) through a brake cable (Cl), the interlocked brake device leaving an effective stroke necessary to cause the front wheel brake (Bf) to work both in the brake operating part (LI) and the master cylinder (M) even while the hydraulic actuator (A) is working with full stroke.
2. An interlocked brake device for a motor vehicle as claimed in
claim 1, wherein said working lever (25) and a second brake
operating part (12) are coupled through a second brake cable
(C2) so that the rear wheel brake (Br) is caused to work also by
the second brake operating part (L2).
3. An interlocked device for a motor vehicle substantially as
hereinbefore described with reference to and as illustrated in
the accompanying drawings.

Documents:

831-del-1997-abstract.pdf

831-del-1997-claims.pdf

831-del-1997-correspondence-others.pdf

831-del-1997-correspondence-po.pdf

831-del-1997-description (complete).pdf

831-del-1997-drawings.pdf

831-del-1997-form-1.pdf

831-del-1997-form-13.pdf

831-del-1997-form-19.pdf

831-del-1997-form-2.pdf

831-del-1997-form-3.pdf

831-del-1997-form-4.pdf

831-del-1997-form-6.pdf

831-del-1997-gpa.pdf

831-del-1997-petition -137.pdf

831-del-1997-petition-138.pdf

abstract.jpg


Patent Number 214902
Indian Patent Application Number 831/DEL/1997
PG Journal Number 10/2008
Publication Date 07-Mar-2008
Grant Date 18-Feb-2008
Date of Filing 31-Mar-1997
Name of Patentee NISSIN KOGYO CO., LTD.
Applicant Address 840, OAZA KOKUBU, UEDA-SHI, NAGANO, JAPAN.
Inventors:
# Inventor's Name Inventor's Address
1 NAOKI KOBAYASHI C/O NISSIN KOGYO CO., LTD, 840, OAZA KOKUBU, UEDA-SHI, NAGANO, JAPAN
2 ISAO MATSUNO C/O NISSIN KOGYO CO., LTD, 840, OAZA KOKUBU, UEDA-SHI, NAGANO, JAPAN
PCT International Classification Number F16D 65/21
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 HEI-8-89475 1996-04-11 Japan