WO2008117310A1

WO2008117310A1 - Improved alternator with integrated mounting and belt tensioning arrangement

Info

Publication number: WO2008117310A1
Application number: PCT/IN2008/000177
Authority: WO
Inventors: Narendra Kumar Jain; Hemant Ambadas Malekar; Kedar Digambar Gokhale
Original assignee: Tata Motors Limited
Priority date: 2007-03-28
Filing date: 2008-03-24
Publication date: 2008-10-02

Abstract

This invention relates to an improved Alternator (1) and more in particular with the mounting and tensioning arrangement of alternator (1) and mounting method thereof, which is used for on board charging of the vehicle battery. Typically the alternator (1) is driven by the base driving unit such as internal combustion engine using a cogged V / poly V belt. The direct mounting of the alternator (1) on the base driving unit without any bracket is devised with the belt (5) tensioning arrangement integral to the alternator housing. This eliminates the need of a separate bracket and its hardware for mounting the alternator (1). Further it eliminates the tensioner pulley for tensioning the drive belt (5) which results in substantial reduction in weight and cost of the system.

Description

IMPROVED ALTERNATOR WITH INTEGRATED MOUNTING AND BELT TENSIONING ARRANGEMENT

FIELD OF INVENTION

This invention relates to an alternator intended for cost effectiveness and more particularly it relates with the integrated mounting of the alternator and tensioning arrangement of its belt drive.

BACKGROUND OF THE INVENTION

Conventionally the accessories like alternator, air conditioning compressor, power steering pump etc. are mounted on the base unit for instance an engine using separate brackets. These accessories are driven by the base driving unit viz. damper pulley for an engine, through the cogged V or poly V belts. These belts need a tensioning arrangement which facilitate the tensioning of the belt to ensure low noise, efficient power transmission to the accessories and long life of the belt. Typically the tensioning is achieved either through an automatic (spring loaded) tensioner pulley or a manually adjusted tensioner pulley for tensioning the belt.

The provision of separate bracket for mounting these accessories always face the packaging, strength, durability and Noise-Vibration-Harshness (NVH) related problems in addition to the cost. Further, the separate tensioner pulley also increases the weight and cost of the system.

BACKGROUND OF ART

US 4512752 disclose an engine with alternator [9] mounted on two separate brackets [10]. The tensioning device includes one angle bracket secured to a slotted plate having an arcuate slot [11] formed about a pivot axis on which the accessory is angularly adjustable. An adjustment bolt secures another angle bracket to the slotted plate and is extended through the arcuate slot [11] and threaded into the accessory. A machine screw extends between the two angle brackets [10] and is threaded through one of them. The screw drives the brackets toward and away from one another to adjust the belt tension when the screw is turned with the adjustment bolt [13] loosened. When the adjustment bolt [13] is tightened, it locks the accessory in place. Second bracket has an arcuate slot [11] which in loose condition permits angular adjustment of the alternator for the sole purpose of belt [12] tightening, which is shown more specifically in Figure 1.

OBJECT OF INVENTION

The main object of this invention is to provide an Alternator having a provision for mounting directly on the base unit without using any bracket/s.

Yet another object of this invention is to provide the belt tensioning arrangement integral to the mounting of the alternator and eliminate the need of a separate tensioner pulley.

Yet another object of this invention is to provide an alternator and its belt drive arrangement which is simple in construction and cost effective.

STATEMENT OF INVENTION

An Improved alternator with integrated mounting and belt tensioning arrangement comprises stator, rotor, and alternator housing, wherein said alternator housing is provided with integrated mounting for alternator and tensioning arrangement for drive belt. Alternator in which mounting for alternator and tensioning arrangement for drive belt is an arcuate slot provided at one end and an extended lug with through hole provided at other end of said alternator housing.

Alternator in which mounting for alternator and tensioning arrangement for drive belt is arcuate slots provided at both ends on said alternator housing.

Alternator wherein rear surfaces of top and bottom mounting are coplanar.

Alternator in which said extended lug is provided with internal threads.

Alternator in which said alternator housing is manufactured by gravity die casting or pressure die casting or sand casting or forging method.

Internal combustion engine and Gas turbine fitted with alternator.

Method of mounting the alternator to base unit comprises following steps: a. Alternator is hinged at the bottom mounting means and swiveled to its fully collapsed/extreme left position on the arcuate tensioning slot; b. Assemble the drive belt on driving and driven pulleys; c. Swivel the alternator about the axis of bottom mounting means until the desired level of tension is achieved in the drive belt; d. Tighten the top mounting means and bottom mounting means with appropriate tightening torque.

BRIEF DESCRIPTION OF INVENTION

The invention mainly relates to an alternator which has integrated mounting and tensioning arrangement with its housing. The bottom mounting of the alternator acts as a hinge, about which the alternator can be swiveled to tension the belt. The top mounting of alternator is provided with an arcuate slot, the centre of said arc coincides with the bottom mounting axis. This slot facilitates various fixing positions for top mounting means. The drive belt for alternator can be tensioned as per requirement initially as well as during the field service with simple tools and average skills. This arrangement eliminates the need of a separate tensioner pulley for tensioning the drive belt and bracket/s which results in substantial reduction in weight and cost.

DEATIL DESCRIPTION OF INVENTION

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.

Figure 1 shows the conventional way of mounting an alternator with the help of mounting brackets.

Figure 2 shows improved alternator housing with integrated mounting and tensioning arrangement.

Figure 3 shows improved alternator mounted on the base unit such as an internal combustion engine

Now referring to figures 2 and 3

The housing of alternator [1] is provided with an integrated arcuate slot [8] which can be achieved either by gravity die casting, pressure die casting or sand casting method. It is directly mounted on the base unit with the help of two mounting means [3, 4]. The bottom mounting means [4] is fastened through the extended lug [8A] provided in the alternator housing onto the base unit. This bottom mounting forms the fixed support of the alternator. The upper mounting means [3] is fastened through the integrated slot [8] onto the base unit. This upper mounting forms the variable / movable support for the alternator as per the drive belt tensioning requirement.

The arrangement for the "Bottom Mounting Means" (4) may be also provided in the form of an "Arcuate Slot" in place of the "Extended Lug" in the Alternator Housing.

The "Extended Lug" may be also provided with internal threads and an appropriate corresponding fastener may be used for tightening of the alternator to the Base Unit.

To mount the alternator [1] initially, it is hinged at the bottom mounting means [4] and swiveled to its fully collapsed (extreme left) position on the tensioning slot. The drive belt [5] is then assembled on the driving and driven pulleys in this position. The belt is in loose / slack condition at this time. The alternator is then swiveled about the axis of bottom mounting means [4]. Thus the centre distance of the alternator pulley [6] and the driving pulley [7] on the base unit is varied manually and the drive belt [5] is tensioned to the desired level. After tensioning the belt [5], the top mounting means [3] and bottom mounting means [4] are tightened which hold the alternator [1] firmly in this position on the base unit.

The drive belt [5] is prone to loose its tension during its operation over the period of time. After loosening, the belt slip increases and results in belt wear, squeaking noise and power loss. Hence this belt needs to be tensioned periodically on the base unit to the desired level of tension. To tighten the belt [5], both the mounting means [3, 4] are loosened and alternator [1] is swiveled, manually, about the axis of bottom mounting means [4]. Once the desired belt tension is achieved both the mounting means [3, 4] are again fastened. This arrangement completely eliminates the use of bracket/s for mounting of the alternator [I]. It also facilitates the tensioning of the belt [5] without additional tensioner pulley. Both these features offer substantial reduction in the complexity and the cost.

The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

Claims

1. An Improved alternator with integrated mounting and belt tensioning arrangement comprises stator, rotor, and alternator housing, wherein said alternator housing is provided with integrated mounting for alternator and tensioning arrangement for drive_.belt.

2. Alternator as claimed in claim 1, wherein said mounting for alternator and tensioning arrangement for drive belt is an arcuate slot provided at one end and an extended lug with through hole provided at other end of said alternator housing.

3. Alternator as claimed in claim 1, wherein said mounting for alternator and tensioning arrangement for drive belt is arcuate slots provided at both ends on said alternator housing.

4. Alternator as claimed in claim 1 to 3. wherein the rear surfaces of top and bottom mounting are coplanar.

5. Alternator as claimed in claim 1 and 2 wherein said extended lug is provided with internal threads.

6. Alternator as claimed in any of the preceding claims wherein said alternator housing is manufactured by gravity die casting or pressure die casting or sand casting or forging method.

7. Internal combustion engine fitted with alternator as claimed in claims 1 to 6.

8. Gas turbine fitted with alternator as claimed in claims 1 to 6.

9. Method of mounting the alternator as claimed in claims 1 to 5 to base unit comprises following steps: a. Alternator is hinged at the bottom mounting means and swiveled to its fully collapsed/extreme left position on the arcuate tensioning slot; b. Assemble the drive belt on driving and driven pulleys; c. Swivel the alternator about the axis of bottom mounting means until the desired level of tension is achieved in the drive belt; d. Tighten the top mounting means and bottom mounting means with appropriate tightening torque.

10. An Improved alternator with integrated mounting and belt tensioning arrangement substantially as herein described with reference to fϊg.2 and 3 of the accompanying drawings.