DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
SYSTEM FOR ELIMINATING CAVITATION AND OPTIMISING CYCLE TIME IN THE HYDRAULIC CIRCUIT OF CONSTRUCTION VEHICLE

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru - 560 027,
Karnataka, India

The following specification particularly describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

[001] The present invention claims priority from Indian patent Provisional Application 202041008403 filed on 27 February 2020.

TECHNICAL FIELD
[002] The present invention relates to eliminating cavitation in hydraulic circuit and more particularly to a system for eliminating cavitation and optimising the cycle time in the hydraulic circuit of construction vehicle.
BACKGROUND
[003] Generally, Excavators perform various operations such as boom raise and boom down using double acting boom cylinders, arm in and arm out using double acting arm cylinders, bucket curl and bucket dump using double acting bucket cylinders, face shovel bucket opening and closing using double acting bottom dump cylinders. Travel forward, travel reverse, steering RH and LH using bidirectional travel motors.
[004] The capacity of a variable displacement axial piston pump is restricted to 190cc/rev and requirement of oil flow is very high to achieve the standard cycle time during Boom lift, Arm and Bucket operation hence, the oil flow of the pump will be added logically. Further, during operation of an individual operation, all four pumps flow will be utilized. In case of Individual operations all four-pump flow are utilized. Since the availability of partition/ provisions in the main control valve is restricted, maximum two pump flow are utilized for the individual operations and while doing combined operation, the pump flow will be divided as per the priority to fulfill the requirement.
[005] The requirement of each individual aggregates is different and there is no separate pump for each an individual application. In case of an individual operation like boom raise, arm out and bucket curl need to add all the four pumps flow to get a standard cycle time and oil flow requirement of these individual applications are very high. Further, in case of combined operations like arm out and bucket curl all the four pumps are not available to an individual application. In such conditions, it is required to split the pump flow in the ratio of 3:1 or 2:2 on priority, using priority control valves in a pilot circuit. However, this affects the cycle timings and performance of the equipment. In addition, main control valve is having limited provisions or partitions, for directing the oil flow to the particular aggregates.
[006] Due to lack of hydraulic oil flow in the hydraulic system, during the particular individual operations like Arm In and Bucket Dump, it leads to failure of oil seals in the hydraulic cylinders, also reduces the cycle time, and in turn reduces the performance of the equipment.

OBJECT OF THE INVENTION

[007] The object of the invention is to develop a system for eliminating cavitation and optimising cycle time in hydraulic circuit of construction vehicle.
[008] Another object of the invention is to introduce monoblock in the hydraulic circuit of construction vehicle to increase the provisions or partitions, for directing the oil flow to the particular aggregates.
[009] Yet another object of the invention is to make use hydraulic oil flow of three pumps via monoblock to carry out operation of the attachments of construction vehicle.

SUMMARY
[0010] Before the present system and method are described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to a system for eliminating cavitation and optimising cycle time in a hydraulic circuit of vehicle, and the aspects are further elaborated below in the detail description.

[0011] In one implementation, a system for eliminating cavitation and optimising cycle time is disclosed. The system consists of introducing a monoblock as a single spool control in a main hydraulic circuit to provide an additional provision in a main control valve. Addition of the monoblock directs use of 3 pumps to carry out arm in and bucket dump operations.

STATEMENT OF INVENTION
[0012] Accordingly, the present invention discloses cavitation elimination system for construction vehicle comprising of atleast one monoblock configured in hydraulic circuit of vehicle and atleast four pumps configured to carry out operations of vehicle attachments.
[0013] Accordingly, the present invention discloses monoblock configured to allow hydraulic oil flow from three pumps to carry out operation of vehicle attachments and activation of monoblock is done by operator through joystick configured on vehicle control panel. The system optimizes the cycle time of carrying out the attachment operations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The foregoing summary, as well as the following detailed description of embodiment, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawing.
[0015] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
[0016] Figure 1 illustrates block diagram of system to eliminate cavitation and optimising the cycle time in hydraulic circuit of construction vehicle when monoblock is used.
[0017] Figures depicts various embodiments of the present disclosure for purpose of illustration only. Only skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0018] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words “comprising”, “having”, and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, systems and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms..
[0019] Various modification to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to another embodiment. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein..
[0020] Thus, the present invention describes a system for eliminating cavitation and optimising cycle time in a hydraulic circuit of a vehicle. The system includes introduction of a monoblock (40) in the main hydraulic circuit. After introducing the monoblock (40), it enables use of three-pump flow in place of two pumps.
[0021] Now referring to Figure 1, it shows cavitation elimination system, when the monoblock (40) spool is activated using a joystick or a PPC valve pump flow from three pumps is utilized for the operation of vehicle attachments. This reduces the cycle time for carrying out operation of attachment and cavitation free operation of the hydraulic circuit in construction vehicle.
[0022] The hydraulic system, consist of a four variable displacement axial piston. These pumps are coupled to an engine, an electric motor, or a prime mover through a power take off (PTO). Once the prime mover starts rotating, these pumps will start discharging an oil flow. To eliminate, over heating issue (due to friction between oil and inner surfaces of the pipes and hoses) and getting better utilization of a hydraulic energy, the prime movers RPM is controlled, based on the demand of the system. Which intern reduces the pump RPM and discharge volume of the pumps. These positive displacement pumps are kept in de-stroke condition to discharge only minimum flow, when there is no demand. This minimum flow is very much essential for internal lubrication of the pumps.
[0023] Based on a demand, the pumps can discharge maximum flow by switching over to a maximum stroke position or a maximum swash plate angle by getting a feedback from a pilot control system. To fulfil the demand, all the four positive displacement pumps can be energized to discharge the maximum flow and in few cases like arm in and bucket dump individual operations, maximum of three-pump flow is sufficient, to achieve a standard cycle time. Therefore, only three pumps will be energized to discharge the maximum flow using a feedback signal.
[0024] The main control valve consists of a spool to direct the pumps flow to the aggregates like hydraulic cylinders or hydraulic motors. The spool movements is controlled by the pilot control system through joysticks. Each spool is dedicated, to a particular application, like a boom raise, a boom down etc. Further; each spool is having two separate ports, to direct the pump flow to a particular aggregate. As an example, if port A1 in spool 1, directs the pump flow to the boom cylinder, boom raise operation happens. Further, If port B1 in spool 1, directs the pump flow to the boom cylinder, boom down action occurs. Furthermore, by considering each four spools as a cluster or segment, the main control valve consists of four segments (16 spools are kept in four separate segments, as four spools / segment). Thus, when one segment in control valve directs one pump flow to four different aggregates, one after the other, based on the requirement or feedback signal from the pilot control system. For operations such as boom raise, arm out and bucket curl operation, since the flow requirement is very high, there is a need to direct all the four-pump flow through all the four segments of the main control valve.
[0025] After introducing the mono block, pump P3 oil flow will be directed to mono block and in turn, it is to be used exclusively for arm in and bucket dump operations. Thus, whenever arm in and bucket dump operations are performed, the first priority is given to these particular applications.
[0026] Further, the invention can be used, but not limited to, in the following applications.
[0027] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0028] Some embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0029] Some embodiments resolve the cavitation problem and improves cycle time in a hydraulic excavator.
[0030] Some embodiments may optimize performance of the hydraulic excavator.
[0031] REFERRAL NUMERALS:
Element Description Reference Numeral
monoblock 40
cavitation elimination system 100

,CLAIMS:
1. A cavitation elimination system (100) for a construction vehicle comprises;
atleast one monoblock (40) configured in hydraulic circuit,
and atleast one pump (P1, P2, P3 and P4) are configured to operate vehicle attachments.

2. The cavitation elimination system (100) for a construction vehicle as claimed in claim 1, wherein said atleast one pump (P3) is configured to be connected to monoblock (40) to transfer hydraulic oil for operating vehicle attachments.
3. The cavitation elimination system (100) for a construction vehicle as claimed in claim 1, wherein said monoblock (40) is configured to provide hydraulic oil flow from atleast three pumps to operate vehicle attachments.
4. The cavitation elimination system (100) for a construction vehicle as claimed in claim 1, wherein the activation of monoblock (40) is configured to be operated through joystick on vehicle control panel.
5. A cavitation elimination system (100) for a construction vehicle as claimed in claim 1, wherein said pumps are configure to operate system without cavitation by optimizes the cycle time of the attachment operations.