Claims:We Claim:
1. A system (100) for facilitating tension setting of a front end accessories drive belt (140) mounted on a damper pulley (130) of an automotive engine (150), the system (100) comprising:
a hydraulic motor unit (30) having a hydraulic motor (17) mounted on a bracket (18); a motor shaft (19) rotatably fitted in a journal bearing and mounted on a front plate (3) of the bracket (18); a bi-hex socket (20) coupled to the motor shaft (19) and configured for engaging with a damper pulley bolt (135); a locating pin (1) for engaging with the locating hole of the engine cylinder block, press fitted inside a bush (2) bolted on the front plate (3); wherein the hydraulic motor (17) is a relay operated and timer controlled motor and the timer is prior fed with time taken for one complete rotation of belt; and
a pneumatic cylinder unit (50) mounted on a vertical column (11) of adjustable height and a linear rail guide (9) for lateral movement thereof; the pneumatic cylinder unit (50) having a pneumatic cylinder (12) operable with a reed switch and a magnetic plug and mounted in a cylinder mounting bracket (5); at least two sliding pins (13) guiding the horizontal movement of a pneumatic cylinder rod (21) and connecting the pneumatic cylinder unit (50) with the hydraulic motor unit (30) in such a way that the pneumatic cylinder rod (21) on actuation of the pneumatic cylinder (12) pushes the hydraulic unit (30) horizontally;
wherein, positioning of the drive belt (140) is done by first engaging the locating pin (1) with the engine cylinder block by adjusting the height of vertical column (11); manually aligning the bi-hex socket (20) with the damper pulley bolt (135); actuating the pneumatic cylinder (12) to push the hydraulic unit (30) thereby ensuring firm coupling of motor shaft (19) with the damper pulley (130); and rotating the damper pulley (130) at least three times and
tension setting of the drive belt (140) is done by measuring the oscillation frequency of the drive belt (140) along a larger belt section (140A) between two pulleys of front end accessories drive; comparing the oscillation frequency reading with the optimal oscillation frequency value and adjusting the tension in the drive belt to match the optimal oscillation frequency value.
2. The system (100) as claimed in claim 1, wherein the front end accessories drive belt (140) is 6pk type poly V ribbed belt.
3. The method (200) for facilitating tension setting of a front end accessories drive belt (140) mounted on a damper pulley (130) of an automotive engine (150), the method (200) comprising:
engaging the locating pin (1) with the engine cylinder block by adjusting the height of vertical column (11);
engaging the bi-hex socket (20) with the damper pulley bolt (135);
actuating the pneumatic cylinder (12) to push the hydraulic unit (30) thereby ensuring firm coupling of motor shaft (19) with the damper pulley (130);
switching ON the hydraulic motor (17) to rotate the damper pulley (130) at least three times;
measuring the oscillation frequency of the drive belt (140) along a larger belt section (140A) between two pulleys of front end accessories drive;
comparing the oscillation frequency reading with the optimal oscillation frequency value; and
adjusting the tension in the drive belt to match the optimal oscillation frequency value.
4. The method (200) as claimed in claim 1, wherein the front end accessories drive belt (140) is 6pk type poly V ribbed belt.
Dated this 5th day of February 2018

Ashwini Kelkar
Agent for Applicant
(IN/PA-2461)
, Description:invention.
SYSTEM AND METHOD FOR FACILITATING TENSION SETTING OF FRONT END ACCESSORIES DRIVE BELT IN AUTOMOTIVE ENGINE
Field of invention
The present invention relates to an electro-mechanical system for front end accessories drive (FEAD) belt stabilization to felicitate tension setting in internal combustion engine, and more particularly, the present invention relates to a system for rotating damper pulley mounted on crankshafts to obtain correct positioning of the drive belt and felicitate drive belt tension setting.
Background of the invention
A drive belt (hereinafter referred to as a belt) is provided to drive various accessories of front end accessories drive (FEAD) system which is subsystem of engine driven by engine torque. These accessories include alternator, compressor, water pump, power steering pump. These accessories are driven by a damper pulley. The damper pulley is mounted over a crankshaft. Since all the accessories are driven by the belt, therefore it is required that the belt crater seats properly on flank of individual pulleys and vice versa. Moreover, it is also necessary to provide correct static tension adjustment to the belt as it powers important accessories of the of front end accessories drive.
It is evident that proper operation and performance of accessories of the of front end accessories drive, without any lag, directly depends upon the correct stretching i.e. tension in belt. As per current practice, the FEAD system uses a poly V ribbed belt which ensures the non-positive transfer of torque from crankshaft to alternator, coolant pump and the like. The poly V ribbed belt provides reduced warp radii therefore increase in transmission ratio for allowing different RPM of accessories. Specifically, the accessories can be driven from reverse or front side of the poly V ribbed belt. The poly V ribbed belt is of 6pk type where 6 means it has 6 grooves (6 craters and 7 flanks) and pk signifies the material type.
During assembly of the belt, after various accessories, it thus becomes important to adjust the belt tension by belt tensioner or adjuster bolt below the belt. The recommended value for belt tension is 172-182 Hz. If the belt tension is below the recommended value, then the tension may possibly be eliminated due to internal stress relieving and elongation as belt heats up when it rotates on the vehicle end and it may come out of pulley grooves. Further, the belt can also produce squeak or squeal noise. If the belt tension is above the recommended value, then the belt and the pulley may slide past each other which can eventually lead to seizure and the belt may wear out or break over a period of time.
In the current practice, the belt tension is insured by measuring tension on the engine side which has larger portion of the belt between two pulleys of any accessories or idlers i.e. alternator and compressor. Specifically, a sonic tension meter is placed adjacent to the belt and small disturbance is produced in the belt. If value of tension is not optimal then tensioner pulley or bolt, whichever is applicable, is tightened inward or outward to the system depending upon slack or tight. More specifically, the belt tension is adjusted when damper pulley is at its marked position.
However, high skill is required in this operation as the fitment of belt on individual have to be acknowledged for the belt tensioning condition and tension setting is done depending upon the reading from the sonic meter. As in the prior art, the belt tension is measured by the sonic belt tension meter without actual rotation of belt with the accessories, during assembly buy off these can lead to phenomena called drive failure.
Specifically, drive failures occur due to the false tension measurements in following conditions:
1. Belt internal stresses not relieved after manufacturing.
2. Improper fitment of belt V groove on pulleys i.e. superposition of crest on crest or trough on trough.
3. Accessories misalignment or loose torqueing.
4. Drive train vibration due to resonance.
Due to the false measurement of the tension a lot of technical failures are detected at the customer end which affects the overall performance of the vehicle causing customer dissatisfaction with the product. Few of the recorded issues faced by the customers are mentioned herein:
1. Belt pulley Interfacial sliding due to pulley rotation tight issues
2. Reduced output and performance of the FEAD system
3. Belt quality defect like abnormal squeak noise and premature belt wear which can cause safety hazard
US Patent Application 20040102272 discloses a mechanism in which engine accessory drive belt tension is maintained by a spring loaded roller positioned to impinge against the belt. The belt deflection is reflected by changes in position of the roller, and measured by a deflection sensor. Changes in deflection may indicate changes in belt elasticity, indicating the possible need to change the belt.
Another US Patent 8840495 discloses a belt tensioner for tensioning a belt, comprising a pivot shaft that is fixedly mountable with respect to an engine block of an engine, a tensioner arm rotatably mounted to the pivot shaft for pivoting about a tensioner arm axis in a first direction and in an opposing second direction, a pulley rotatably mounted to the tensioner arm for rotation about a pulley axis, and a tensioner spring positioned to bias the tensioner arm in the first direction, wherein the tensioner spring has a first end and a second end, wherein the first end is engaged with the tensioner arm, and a micro adjustment mechanism that is operatively connected to control the position of the second end of the tensioner spring so as to control the tension in the tensioner spring.
Yet another US Patent 9739349 discloses a tensioning system which includes a drive assembly, an accessory mount coupled with the drive assembly, and an accessory system coupled with the accessory mount. The accessory mount is arranged to apply tension to at least one of the drive assembly and the accessory system.
However, the belt tensioning methods and systems of the prior art works without actual rotation of belt with the accessories, and are very cumbersome. Accordingly, there exists a need to provide a system and method for adjusting drive belt tension during assembly of engine which overcomes drawbacks of the prior art.
Objectives of the present invention:
An object of the present invention is to provide a belt rotation unit for internal combustion engine which has v-ribbed grooved belts on its FEAD system.
Another object of the present invention is to eliminate drive failure which could occur due to miss-adjusted seating of crater and flank of belt and pulley and otherwise also.
Yet another object of the present invention is to reduce manual intervention in belt tensioning operation thereby reducing operator irritant and muscular fatigue inherent in earlier procedure.
Summary of the invention
The present invention provides a system for facilitating tension setting of front end accessories drive belt and a method thereof. Tension setting of the FEAD belt is done after actual rotation of the drive belt with accessories. Front end accessories are driven by the damper pulley on which the drive belt is mounted. Since all the accessories are driven by belt therefore it is required that the belt crater seats properly on flank of individual pulleys and vice versa. The system of present invention comprises of a pneumatic cylinder unit and a hydraulic motor unit. The drive belt along with accessories is rotated for three times by firmly coupling the damper pulley bolt with a bi-hex socket fitted on a hydraulic motor drive shaft. The hydraulic motor is provided with a timer for ensuring the predefined rotation time. A pneumatic cylinder unit on actuation ensures firm coupling of the damper pulley bolt with the bi-hex socket, by applying force. After completing three rotations and positioning of the belt, a portion of the belt between two pulleys is oscillated and frequency of oscillations is measured using a tension meter. Tension in the drive belt then adjusted depending upon the tension meter reading.
Brief description of the figures:
The objectives and features of the present invention will be more clearly understood from the following description of the invention taken in conjunction with the accompanying drawings, wherein,
Figure 1 shows a system for facilitating tension setting of front end accessories drive belt, adjusted on rear side of an automotive engine and aligned with the damper pulley, in accordance with the present invention;
Figure 2 shows detailed view of the system for facilitating tension setting of front end accessories drive belt, in accordance with the present invention;
Figure 3 shows top view of the system for facilitating tension setting of front end accessories drive belt, in accordance with the present invention;
Figure 4 shows perspective view of the s system for facilitating tension setting of front end accessories drive belt, adjusted on rear side of the automotive engine and aligned with the damper pulley, in accordance with the present invention;
Figure 5 shows backside view of the system for facilitating tension setting of front end accessories drive belt, adjusted on rear side of the automotive engine and aligned with the damper pulley, in accordance with the present invention;
Figure 6 shows a line diagram showing the manner in which system for facilitating tension setting of front end accessories drive belt communicates internally; in accordance with the present invention; and
Figure 7 shows a flowchart of a method for setting a belt tension using the system for facilitating tension setting of front end accessories drive belt in accordance with the present invention.
Detailed description of the present invention:
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.
The present invention in one aspect provides a system for positioning of automotive engine front accessories drive belt and for facilitating its tension adjustment during assembly of the engine. The system comprises of a hydraulic motor unit and a pneumatic cylinder unit. The system is properly aligned with the damper pulley bolt of the automotive engine and the bi-hex socket fitted on the motor shaft is coupled to the damper pulley bolt. Proper coupling of the bi-hex socket with the drive pulley bolt is ensured by first aligning the damper pulley bolt and the bi-hex socket and then actuating the pneumatic cylinder to push the hydraulic motor unit thereby applying force on the coupling. The damper pulley is then rotated by switching on the hydraulic motor. The system is provided with timer which allows the hydraulic motor to rotate the damper pulley three times. The information regarding degree of rotation of damper pulley, with respect to FEAD system, to obtain three rotation of it, is stored in timer. The belt mark position is taken as datum. Rotating the drive belt with the accessories ensures the proper positioning of the drive belt. Belt tension is then measured by oscillating the belt on its larger portion between two pulleys and bringing the tension meter near it to measure the frequency of oscillation. The tension meter value is compared with the recommended frequency value of the belt. For the non-complying values of frequency, belt is loosened by loosening the tensioner pulley bolt and over-torqueing or under-torqueing it, depending upon the frequency value. The whole process is repeated till the accurate oscillation frequency value is achieved. Thus, the manual rotation of damper pulley is eliminated.
In another aspect, the present invention provides a method for positioning of automotive engine front accessories drive belt and for facilitating its tension adjustment during assembly of the engine. In the method, the locating pin is first engaged with the locating hole of the engine cylinder block and the bi-hex socket is then coupled to the damper pulley bolt of the engine. When the control switch is switched ON, the communication is relayed for actuating the pneumatic cylinder which pushes the hydraulic unit and ensures proper coupling of the bi-hex socket with the damper pulley bolt. In the next step, the timer is switched ON and the hydraulic motor is activated. Motor rotates the damper pulley with drive belt fixed on it and stops after completing three rotations. In the further step, belt tension is measured by oscillating a portion of drive belt between two pulleys and measuring the oscillating frequency using tension meter. Pneumatic cylinder is then switched OFF to retract. Belt is loosened or fastened depending upon the tension meter reading and all the steps are repeated till the oscillation frequency value of the drive belt is found accurate or within set limits.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description. Table 1 provided below lists the components and their respective reference numbers:
Ref. No. Component name Ref. No. Component name
01 Locating Pin 16 Floating joint
02 Locating pin bush 17 Hydraulic motor
03 Front plate 18 Motor mounting bracket
04 Handle 19 Drive shaft of motor
05 Cylinder mounting bracket 20 Bi-hex socket
06 Vertical plate 21 Pneumatic cylinder rod
07 Middle plate 30 Hydraulic motor unit
08 Metallic rib plate 50 Pneumatic cylinder unit
09 Linear rail guide 130 Damper pulley of engine
10 Stopper 135 Damper pulley bolt
11 Vertical column 140 Drive belt of engine
12
13 Pneumatic cylinder
Sliding pins 140A Larger portion of drive belt between two pulleys
14 Brass bush 150 Automotive engine
15 Bush 200 Tension meter

Referring now to figures 1- 6, there is shown a system (100) for positioning and tension adjustment of a front end accessories drive belt (140), (hereinafter “the system (100)”) during assembly of an automotive engine (150), in accordance with the present invention.
The system (100) comprises of a hydraulic motor unit (30) and a pneumatic cylinder unit (50). The hydraulic motor unit (30) includes a relay operated hydraulic motor (17) mounted on a bracket (18). The motor mounting bracket (18) includes a front plate (3) attached thereto. A motor shaft (19) is rotatably fitted into a journal bearing and mounted on the front plate (3) with brass bush supports. This is done to provide alignment to motor shaft (19). The hydraulic motor shaft (19) is fitted with the bi-hex socket (20) through a pin. The bi-hex socket (20) is configured for engaging with a damper pulley bolt (135) of the automotive engine (150). A locating pin (1) press fitted inside a bush (2) is bolted on the front plate (3) and fitted with a handle (4) for engaging the locating pin (1) inside a locating hole of the engine cylinder block.
The pneumatic circuit unit (50) is mounted on a vertical column (11) of adjustable height. The pneumatic circuit unit (50) includes a pneumatic cylinder (12) mounted in a cylinder mounting bracket (5). Pneumatic cylinder (12) is provided with a reed switch and magnetic plug. The cylinder mounting bracket (5) is fitted on a linear rail guide (9) for lateral movement thereof. A vertical plate (6) is configured for holding the pneumatic cylinder (12). On actuation, the pneumatic cylinder rod (21) of the pneumatic cylinder (12) moves horizontally. The horizontal movement of the pneumatic cylinder rod (21) is guided by at least two sliding pins (13) each extending through a brass bush (14) mounted on the vertical plate (6) and fitted to the bracket (18) through a bush (15). Thus, on actuation of the pneumatic cylinder (12), the pneumatic cylinder rod (21) pushes the hydraulic unit (30) horizontally.
A middle plate (7) and a metallic rib plate (8) are provided for guiding the sliding pins (13). The pneumatic cylinder (12) is used for applying force, when the damper pulley bolt (135) and bi-hex socket (20) are aligned. The pneumatic cylinder rod (21) on actuation of the pneumatic cylinder (12) pushes the hydraulic motor unit (30) thereby firmly engaging the bi-hex socket (20) on the damper pulley bolt (135). Thereby it is ensured that bi-hex socket (20) is properly meshed with the damper pulley (130).
The system (100) is adjusted on rear side of the automotive engine (150) and made centric with the damper pulley (130) by adjusting the height of vertical column (11) and sliding laterally on linear rail guide (9) with the help of handle (4). Specifically, the system (100) is accurately aligned with the damper pulley (130) and its lateral motion, if any, is arrested by manually engaging and sliding the locating pin (1) inside the locating hole of the cylinder block. Once the system (100) is properly aligned and bi-hex socket (20) is properly coupled to the damper pulley bolt (135), the relay switch is pressed. The hydraulic motor (17) rotates the damper pulley (130) thereby rotating the belt (140) along with front end accessories. The system (100) moreover comprises sensors. After getting confirmation from sensors, the relay drives the hydraulic motor (17). The crankshaft is rotated thereby. Timer attached to the relay ensures that hydraulic motor (17) stops after complete three rotations. This ensures that the belt crater seats properly on flank of individual pulleys and vice versa. Moreover it is also necessary to provide correct static tension adjustment to drive belt (140) as it powers important accessories.
Tension setting of the drive belt (140) is performed by oscillating the belt (140) along a larger belt section (140A) between two pulleys and thereby measuring the frequency by tension meter (170). Once the optimal value of tension is obtained the engine is declared OK.
In another aspect, the present invention provides a method (200) for facilitating tension setting of a front end accessories drive belt (140) mounted on a damper pulley (130) of an automotive engine (150). The method (200) is described in conjunction with the system (100) as shown in Figure 6 and 7. The method comprises of:
engaging the locating pin (1) with the engine cylinder block by adjusting the height of vertical column (11);
engaging the bi-hex socket (20) with the damper pulley bolt (135) thereby coupling the hydraulic motor shaft (19) with the damper pulley (130) ;
actuating the pneumatic cylinder (12) to push the hydraulic unit (30) thereby ensuring firm coupling of motor shaft (19) with the damper pulley (130);
switching ON the hydraulic motor (17) and activating the timer to rotate the damper pulley (130) at least three times;
measuring the oscillation frequency of the drive belt (140) along a larger belt section (140A) between two pulleys of front end accessories drive;
comparing the oscillation frequency reading with the optimal oscillation frequency value; and
adjusting the tension in the drive belt to match the optimal oscillation frequency value.
For the non-complying values of frequency, belt (140) is loosened by loosening the tensioner pulley bolt and thereafter over-torqueing it or under-torqueing it, depending upon whether values of frequency was overshooting or was under lying to that of the prescribed limit. The steps are repeated till correct value is obtained. Thus manual rotation of damper pulley (130) is eliminated.
Advantages of the invention
The electro-mechanical system for tappet clearance setting configured in accordance with the present invention has the following technical and economic advantages:
• The system (100) of present invention saves substantial reworking costs.
• The system (100) provides a rotation mechanism for crankshaft thus preventing operator fatigue and creating ergonomically green stage.
• It avoids/eliminates any incorrect tappet positioning over cam lobe.
• Light Weight system (100) is supported over zero spring balancer for user friendly operation.
• Modular design for multimodal application.
• Compact and robust design.
• Deskilling of tappet setting stage.
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the