Claims:1. A gear based auto adjuster for air disc brakes, comprising:
a piston (1) that is associated with at least one tappet (2), said piston (1) and said at least one tappet (2) being coupled together with a male and a female thread, respectively, and the rotation of the at least one tappet (2) is controlled by an adjuster lever (7) and an adjuster shaft (6), with: the adjuster shaft (6) and the adjuster lever (7) are associated with each other through a helical gear;
the adjuster shaft (6) that is mounted on the driver adjuster shaft (5), said driver adjuster shaft (5) moves forward and rotates the adjuster lever (7) during the forward stroke;
an overload spring (8) that is associated with the adjuster lever (7);
a return spring (3) that facilitates the returning of the piston (1) and the at least one tappet (2) to their initial state,
with:
the adjuster shaft (6) and the at least one tappet (2) are non-parallel, and the drive from the adjuster shaft (6) is transferred to the at least one tappet (2) due to meshing of the helical gear;
said piston (1), said at least one tappet (2), said adjuster shaft (6), said adjuster lever (7) are compactly enclosed inside a piston housing (4); and
said auto adjuster being configured to monitor and automatically maintain the required clearance between the rotor of the air disc brake and friction, during every braking.
2. The gear based auto adjuster for air disc brakes as claimed in claim 1, wherein the at least one tappet (2) is dispensed with, and said gear based auto adjuster for air disc brakes comprising:
a wedge block (9), said wedge block (9) and the piston (1) being mates with each other through angular wedge faces;
the adjuster shaft (6) and the wedge block (9) being coupled together with a male and a female thread, respectively; and the piston being mounted on the piston housing (4). , Description:TITLE OF THE INVENTION: A GEAR BASED AUTO ADJUSTER FOR AIR DISC BRAKES
FIELD OF THE INVENTION
The present invention is related to air disc brakes. Particularly, present invention is related to a gear based auto adjuster for air disc brakes.
BACKGROUND OF THE INVENTION
Air disc brakes, used in commercial buses and trucks, are internally actuated by Twin piston or Single piston, depending on the vehicle application requirement. Considering the cost and requirement of optimized specific usage, it becomes essential to develop an air disc brake with fewer internal adjusting components.
An Indian Patent Application Number 201617026001 discloses a disc brake of the type including a pivoting lever having eccentric journals, which act on a pair of tappets is disclosed. The tappets are adjusted in length by rotation and each tappet has a tappet gear. A centrally located intermediate gear is provided between the tappet gears to form a gear train synchronizing the rotation of the two tappets and therefore ensuring that they remain the same length. The centrally located intermediate gear includes a socket for receiving a centrally located adjuster. The adjuster may be installed and removed from the disc brake through an aperture at the rear of the brake caliper without any substantial disassembly of the brake and without de synchronizing the tappets or even interrupting the gear train between the tappets.
However, the gear trains of the tappets, the intermediate components and the adjuster parts have more losses owing to more number of components used in Adjusting and transmission. Thereby reduces the mechanical efficiency and shall have wider variation in the adjustment clearance on wear and tear.
There is, therefore, a need in the art for a gear based auto adjuster for air disc brakes, which overcomes the aforementioned drawbacks and shortcomings.
SUMMARY OF THE INVENTION
A gear based auto adjuster for air disc brakes is disclosed. The auto adjuster, during every braking, is configured to monitor and automatically maintain the required clearance between a rotor of the air disc brake and friction. A piston that is coupled with an at least a tappet.
The piston and the at least one tappet being coupled together with a male and a female thread, respectively. The rotation of the at least one tappet is controlled by an adjuster lever and an adjuster shaft. The adjuster shaft and the adjuster lever are associated with each other through a helical gear.
The adjuster shaft is mounted on a driver adjuster shaft, said driver adjuster shaft moves forward and rotates the adjuster lever during the forward stroke.
An overload spring that is associated with adjuster lever. A return spring that facilitates the returning of the piston and the at least one tappet to their initial state. Said piston, said at least one tappet, said adjuster shaft, said adjuster lever are compactly enclosed inside a piston housing.
The adjuster shaft and the at least one tappet are non-parallel, and the drive from the adjuster shaft is transferred to the at least one tappet due to meshing of the helical gear.
Alternatively, the at least one tappet is dispensed with, and said gear based auto adjuster for air disc brakes comprises a wedge block, said wedge block and the piston are mating with each other through angular wedge faces. The adjuster shaft and the wedge block being coupled together with a male and a female thread, respectively; and the piston is mounted on the piston housing.
The method of working of the auto adjuster is also disclosed. The disclosed auto adjuster is: simple; cost-effective; manufacturing-friendly; and comprises fewer internal adjusting components. Further, the disclosed auto adjusted does not required any maintenance throughout the lifetime of the brake, hence no removal is required.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the cross-sectional view of an embodiment of a gear based auto adjuster for air disc brakes, in accordance with the present disclosure; and
Figure 2 illustrates an embodiment of a gear based auto adjuster for air disc brakes, in accordance with the present disclosure.
Figure 2 illustrates another embodiment of a gear based auto adjuster for air disc brakes, in accordance with the present disclosure.
Figure 4 illustrates the cross-sectional view of another embodiment of a gear based auto adjuster for air disc brakes, in accordance with the present disclosure; and
DETAILED DESCRIPTION OF THE INVENTION
Throughout this specification, the use of the words "comprise", “have”, “contain”, and “include”, and variations such as "comprises", "comprising", “having”, “contains”, “containing”, “includes”, and “including” may imply the inclusion of an element or elements not specifically recited. The disclosed embodiments may be embodied in various other forms as well.
Throughout this specification, the phrases “at least a”, “at least an”, and “at least one” are used interchangeably.
Throughout this specification, the use of the phrase “auto adjuster” is to be construed as a set of technical components that are communicatively or operably associated with each other, and function together as part of a mechanism to achieve a desired technical result.
A gear based auto adjuster for air disc brakes is disclosed (hereinafter ‘auto adjuster’). As illustrated in Figure 1 and Figure 2, an embodiment of said auto adjuster comprises: a piston (1); an at least a tappet (2); an at least a return spring (3); a piston housing (4); a driver adjuster lever (5); an adjuster shaft (6); an adjuster lever (7); and an overload spring (8). Said piston (1), said at least one tappet (2), said adjuster shaft (6), said adjuster lever (7) are compactly enclosed inside the piston housing (4).
In an embodiment of the present disclosure, the piston (1) is associated with the at least one tappet (2), and the rotation of the at least one tappet is controlled by the adjuster lever (7) and the adjuster shaft (6). The piston (1) and the at least one tappet (2) are coupled together with a male and a female thread, respectively. Alternatively, the piston (1) and the at least one tappet (2) are coupled together with a female and a male thread, respectively. The adjuster shaft (6) is mounted on the driver adjuster shaft (5), said driver adjuster shaft (5) moves forward and rotates the adjuster lever (7) during the forward stroke. The overload spring (8) is associated with adjuster lever (7). The adjuster shaft (6) and the adjuster lever (7) are associated with each other through a helical gear. The adjuster shaft (6) and the at least one tappet (2) are non-parallel, and the drive from the adjuster shaft (6) is transferred to the at least one tappet (2) due to meshing of the helical gear.
In another embodiment of the present disclosure, the auto adjuster, during every braking, is configured to monitor and automatically maintain the required clearance between the rotor of the air disc brake and the friction. If excess clearance is observed between the rotor of the air disc brake and the friction, the adjuster lever (7), after travelling the backlash, transfers the drive to the adjuster shaft (6), thereby the adjuster shaft (6) start rotating. Since, the adjuster shaft (6) is associated with the at least one tappet (2) through the helical gear, the at least one tappet (2) starts rotating due to the rotation of the adjuster shaft (6). As the at least one tappet (2) has only the rotational degree of freedom, said at least one tappet (2) linearly moves the piston (1) forward. Said forward movement of the piston (1) continues until the return spring (3) is compressed. When the brake is released, during the reverse stroke, the piston (1) and the at least one tappet (2) shall return to their initial state due to the expansion of the return spring (3).
In yet another embodiment of the present disclosure, the adjusting lever (7) with the overload spring (8) drives the adjuster shaft (6) for adjustment, slips during overload (excess load) and return. The adjuster lever (7) with the overload spring (8) slips against the mating adjuster shaft (6), when more load is experienced during both forward and reverse strokes.
In yet another embodiment (second embodiment) of the present disclosure, as disclosed in Figure 3, and Figure 4, the at least one tappet (2) is dispensed with, and said auto adjuster comprises a wedge block (9). The wedge block (9) and the piston (1) mates with each other through angular wedge faces. The adjuster shaft (6) and the wedge block (9) are coupled together with a male and a female thread, respectively. Alternatively, the adjuster shaft (6) and the wedge block (9) are coupled together with female and male thread, respectively. The piston is mounted on the piston housing (4).
In second embodiment, if excess clearance is observed between the rotor of the air disc brake and the friction, the adjuster lever (7), after travelling the backlash, transfers the drive to the adjuster shaft (6), thereby the adjuster shaft (6) start rotating. Since, the adjuster shaft (6) has only the rotational degree of freedom, and is associated with the wedge block (9) through threads (screws), moves the wedge block (9) linearly. As the wedge block (9) and the piston (1) mates on their angular wedge faces, the piston (1) advances correspondingly according to the liner movement of the wedge block (9). The adjuster lever (7) with the overload spring (8) slips against the mating adjuster shaft (6), when more load is experienced during both forward and reverse strokes. During the forward stroke, the driver adjuster lever (5) moves and rotates the adjuster lever (7) about its pivot. When the brake is released, during the reverse stroke, the piston (1) and wedge block (9) shall return to their initial state due to the expansion of the return spring (3).
The disclosed gear based auto adjuster for air disc brakes is: simple; cost-effective; manufacturing-friendly; and comprises fewer internal adjusting components. Further, the disclosed auto adjusted does not required any maintenance throughout the lifetime of the brake, hence no removal is required.
It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations and improvements without deviating from the spirit and the scope of the disclosure may be made by a person skilled in the art. Such modifications, additions, alterations and improvements should be construed as being within the scope of this disclosure.
LIST OF REFERENCE NUMERALS
1 – Piston
2 – Tappet
3 – Return Spring
4 – Piston Housing
5 – Driver Adjuster Lever
6 – Adjuster Shaft
7 – Adjuster Lever
8 – Overload Spring
9 – Wedge Block