TECHNICAL FIELD
The subject matter described herein in general relates to an engine starting system and in particular relates to a starter motor for an internal combustion engine.
BACKGROUND
Internal combustion engines utilize air and fuel to perform work. In order to start an engine, a crankshaft of the engine must rotate fast enough for air-fuel mixture to enter the engine cylinder. The internal combustion engine is typically started by a dedicated electric starter motor mounted on the engine. The starter motor converts the electrical energy of the battery into mechanical energy, thereby rotating the crankshaft of the engine. The rotation of the crankshaft enables the piston movement within the engine cylinder.
In a typical configuration, the engine is started by the starter motor when the ignition switch is turned on by the vehicle operator. A pinion is attached to an output shaft of the starter motor and advances to mesh with a ring gear. The output shaft of the starter motor has splines on which the pinion moves back and forth. The movement of the pinion on the output shaft is facilitated by a lever whose movement is controlled by a solenoid of the starter motor. The lever moves forward to direct the pinion towards the ring gear. Once the pinion and the ring gear mesh, the output shaft of the starter motor rotates, thereby rotating the ring gear, which is engaged with the pinion. The rotation of the ring gear results in the rotation of crankshaft. Subsequently an ignition system is also energized to start the engine. Once the engine gets fired and starts running at excessive

speeds, an overrunning clutch breaks the driving connection between the pinion and the starter motor, thereby making the starter motor idle.
A typical electric starter motor system takes close to one second to achieve engine crankshaft rotational speeds sufficient enough to crank and fire the engine. Further, during the cranking and firing process, a significant audible noise is created. Moreover, the pinion cannot withstand continuous overrun abuse if allowed to rotate continuously with the crankshaft of the engine at excessive speeds.
The challenge therefore is to provide a solution that provides a shorter engine cranking and firing time without causing any overrun abuse to the overrunning clutch. Moreover, it is desirable to reduce noise caused by engine cranking and firing. This is particularly important in the case of auto stop-start facility for vehicles.
SUMMARY
The subject matter described herein is directed to a starting system for an internal combustion engine. The starting system comprises a motor, a multiple stage speed reduction assembly, a power transmission assembly and a power transmission member. The motor converts electrical energy into mechanical energy and includes a rotating armature shaft. The speed reduction assembly comprises a first stage epicyclic gear train coupled to the armature shaft and a second stage epicyclic gear train coupled to an output shaft of the first stage epicyclic gear train. The power transmission assembly comprises a journal member, a sleeve member and one or more one-way torque transmitting elements. The journal member is coupled to an output shaft of said second stage epicyclic gear train and the sleeve encompasses the journal member. The one-way torque transmitting

elements are secured between the journal member and the sleeve member, thereby transmitting torque from the journal member to the sleeve member. The sleeve member is rotationally coupled to the power transmission member and drives the power transmission member. The power transmission member in turn provides the required output power to the engine or other components of the vehicle. When the engine is fired, the torque transmitting elements lose contact with the journal member and start rotating with the crankshaft of the engine.
In one embodiment of the present subject matter, a common annulus is provided for both first stage epicyclic gear train as well as second stage epicyclic gear train.
In another embodiment, the speed reduction assembly is a worm gear assembly. The armature shaft is coupled to a worm of the worm gear assembly. The worm engages with a worm gear, which is in turn is coupled to an output shaft. The output shaft of the speed reduction assembly is further connected the power transmission assembly for transmission of power to the engine.
In yet another embodiment, an axis of the motor is inclined to an axis of the speed reducfion assembly.
In yet another embodiment, the power transmission assembly and the power transmission member are integral.
Thus, the time of cranking and firing the engine as well as the noise produced by the starting system is reduced. Moreover, due to separation of the torque transmitting elements with the journal member during normal running of the engine, the wear and tear of the torque transmitting elements is eliminated. Also solenoid switch is eliminated since the starter is permanently coupled to engine. Elimination of solenoid results in reduction

of parts count and hence higher reliability of starter motor is realized. Also this configuration of starter motor facilitates stop-start system for vehicles leading to fuel economy and emission reduction.
These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF DRAWINGS
The novel features of the subject matter are set forth in the appended claims hereto. The subject matter itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein the same numbers are used throughout the drawings to reference like features, and wherein:
Fig, 1 illustrates a sectional view of a starting system for an internal combustion engine of a vehicle depicting a two stage epicyclic gear train acting as a speed reduction assembly in accordance with one embodiment of the present subject matter.
Fig, 2 illustrates a sectional view of the starting system of Fig. 1 depicting an integrated clutch pulley assembly according to another embodiment of the present subject matter.

Fig. 3 illustrates a sectional view of a starting system for an internal combustion engine depicting a worm gear mechanism acting as a speed reduction assembly with respect to yet another embodiment of the present subject matter.
Fig. 4 illustrates a sectional view of a starting system of Fig, 3 depicting an integrated clutch pulley assembly according to yet another embodiment of the present subject matter.
Fig. 5 illustrates a starting system for an internal combustion engine of a vehicle depicting a bevel gear reduction mechanism using roller clutch arrangement in accordance with yet another embodiment of the present subject matter.
Fig. 6 illustrates a starting system of Fig. 5 depicting an integrated clutch pulley mechanism in accordance with yet another embodiment of the present subject matter.
Fig. 7 illustrates a starting system for an internal combustion engine depicting an electromagnetic clutch according to yet another embodiment of the present subject matter.
Fig. 8 illustrates a starting system for an internal combustion engine of a vehicle depicting the use of a split pulley mechanism with roller clutch according to yet another embodiment of present subject matter.
DETAILED DESCRIPTION
A starting system for an internal combustion engine is described herein. The starting system comprises a motor for converting electric energy of a battery into mechanical energy. A speed reduction assembly, comprising a multiple stage epicyclic gear train, is coupled to an armature shaft of the motor to achieve higher speed ratio. The output of the multiple stage epicyclic gear train is coupled to a journal of a roller clutch.

A journal transmits the torque to a sleeve of the roller clutch through rollers. The sleeve is coupled to a power transmission member, which is further coupled to a crankshaft (not shown in the figure) of the engine, thereby transmitting power to the crankshaft of the engine.
Fig. 1 illustrates a sectional view of a starting system 100 for an internal combustion engine (not shown in the figure) of a vehicle depicting a two stage epicyclic gear train acting as a speed reduction assembly in accordance with one embodiment of the present subject matter. For instance and in no way limiting the scope of the invention, the starting system is a starter motor. As shown herein, an armature shaft 102 of a motor 104 is coupled to a first stage sun gear 106. In the present embodiment, a two stage epicyclic gear train (i.e. a first stage gear train 108 and a second stage gear train 110) is used as a speed reduction assembly. The two stage epicyclic gear train is utilized to achieve higher speed ratio between the starting system 100 and the engine. In other embodiments, more than two stage epicyclic gear trains are utilized as speed reduction assembly.
An annulus 112 is a stationary internal gear and is common to the first stage gear train 108 and the second stage gear train 110 in the present embodiment. One or more first stage planetary gears 114 rotate along the inner circumferential teeth of the annulus 112 and are mounted on first stage pins 116 through journal bearings or roller bearings 118. The first stage pins 116 are rigidly connected to a flanged end of a first stage output shaft 120. The other end of the first stage output shaft 120 is coupled to a second stage sun gear 122. In another embodiment, a separate annulus is provided for each of the first stage planetary gears 114 and the second stage planetary gears 124.

One or more second stage planetary gears 124 rotate along the inner circumferential teeth of the annulus 112 and are mounted on second stage pins 126 through journal bearings or roller bearings 128. The second stage pins 126 are rigidly connected to a flanged end of the second stage output shaft 130. A first bearing 132 is used to support the first stage output shaft 120 and the armature shaft 102. The first stage output shaft 120 is rotationally supported on the outer periphery of the first bearing 132 and the armature shaft 102 is rotationally supported at the inner periphery of first bearing 132.
A second bearing 134 is used to the support first stage output shaft 120 and the second stage output shaft 130. The second stage output shaft 130 is rotationally supported on the outer periphery of the second bearing 134 and the first stage output shaft 120 is rotationally supported at the inner periphery of the second bearing 134. Optionally, a spherical ball 136 is placed in the space between the other end of the first stage output shaft 120 and the flanged end of the second stage output shaft 130.
The motor 104, the first stage epicyclic gear train 108 and the second stage epicyclic gear train 110 are housed in a housing 138. The housing 138 is also used to locate the annulus 112, common to the first stage epicyclic gear train 108 and second stage epicyclic gear train 110. The second stage output shaft 130 is supported on a third bearing 140, housed in the housing 138. The second stage output shaft 130 is rotationally coupled to a journal 142 of a roller clutch 146. In the present embodiment, the roller clutch 146 acts as a power transmission assembly and transmits power in one direction towards the engine. One or more rollers 148, supported between the journal 142 and a sleeve 150 of the roller clutch 146, facilitates the transfer of torque from the journal 142

to the sleeve 150. The sleeve 150 has an overhanging portion, which is coupled to a power transmission member. A pulley 164, which is a power transmission member, is connected to the crankshaft of the engine through a belt arrangement, thereby transmitting power from the motor 104 to the engine. Once the engine gets fired and the engine speed is above a predetermined value, the pulley 164 rotates with the crankshaft and the roller clutch 146 freewheels i.e. the sleeve 150 and the rollers 148 rotate with the pulley 164 while the journal 142 remains stationary. During freewheeling, the physical contact between the rollers 148 and the journal is lost, thereby the wear and tear of the rollers 148 is eliminated, and the motor 104 goes to the idle mode.
The pulley 164 may be coupled to a pulley (not shown in the figure) mounted on engine shaft or to any pulley on the accessory applications such as an AC compressor, an alternator, a water pump, a power steering pump etc. through a poly V-groove belt.
The sleeve 150 houses a fourth bearing 152, which supports the second stage output shaft 130. Optionally, a spherical ball 136 is placed in the space between other end of the second stage output shaft 130 and the sleeve 150. The overhanging portion of the sleeve 150 is supported in a fifth bearing 154 housed in a drive end bracket 156. The drive end bracket 156 is located coaxially with the housing 138. A seal 158 is used between the drive end bracket 156 and the housing 138. An oil seal 160 is located in the drive end bracket 156 and the lip of the oil seal 160 is in contact with the outer periphery of sleeve 150. Also, on the gear train side of roller clutch 146, an oil seal 162 is housed inside the housing 138. The lip of the oil seal 162 is in contact with the second stage output shaft 130. The empty space between the housing 138 and the drive end bracket

156 is optionally filled with oil to provide lubrication to the roller clutch 146. The seal 158 and the oil seals 160 and 162 provide sealing for the encapsulated oil.
Fig. 2 illustrates a sectional view of the starting system 100 of Fig. 1 depicting an integrated clutch pulley assembly 190 according to another embodiment of the present subject matter. As shown in the figure, the one-way power transmission mechanism is realized by means of the clutch pulley assembly 190, i.e. the roller clutch 192 and the pulley 194 are combined together to form a single assembly. The other aspects of the subject matter are as described in Fig. 1. The present embodiment facilitates the elimination of parts such as drive end bracket 156, fifth bearing 154 and oil seals 158, 160, thereby reducing the total number of components of the starting system 100.
In further embodiments of the present subject matter as described in Fig. 3 and Fig. 4, the motor power is transmitted to the one way power transmission assembly by means of a worm gear mechanism 200. In the embodiments described in reference to Fig.3 and Fig.4, the two-stage epicyclic gear train is replaced by the worm gear mechanism 200. The usage of worm gear mechanism 200 facilitates the transmission of power provided that the armature shaft and the transmission output shaft are non-parallel and non-intersecting. The other aspects of the embodiment could be similar to those disclosed in Fig. 1 and Fig. 2 respectively.
In other embodiments of the subject matter as described in Fig. 5 and Fig. 6, the axis of the one way power transmission mechanism is inclined from the axis of the motor of the motor. In the embodiments described in Fig. 5 and Fig. 6, the angle of inclination is 90° and is realized by the use of bevel gears 210. In other embodiments, the angle of inclination may be between 0° and 180°. This angle of inclination could be achieved

through the use of bevel gears or a combination of bevel and spur gears. The other aspects of the embodiments could be similar to those disclosed in Fig. 1 and Fig, 2 respectively.
In yet another embodiment of the present subject matter as described in Fig. 7, the pulley is a split type controlling pulley 220, whose mean operating radius can be altered depending on whether the requirement is of power transmission to the engine or of freewheeling after the engine has been fired. The split type controlling pulley 220 is rotationally coupled to the sleeve 150 of the roller clutch 146. The mean operating radius of the split type controlling pulley 220 is varied by an electromagnetic solenoid 230 depending upon the required speed ratio. The electromagnetic solenoid 230 is coupled to a first cone 222 of the split type controlling pulley 220 for sliding the first cone 222 in the axial direction whereas a second cone 224 of the controlling pulley 220 is located at a fixed axial position. The electromagnetic solenoid 230 provides linear mofion to the first cone 222 of the controlling pulley 220. The controlling pulley 220 is coupled to a controlled pulley (not shown in the figure) mounted on the engine shaft by means of a belt (not shown in the figure). In order to enhance the speed ratio, the solenoid 230 drives the first cone 222 towards the motor, thereby reducing the mean radius of the controlling pulley 220. The embodiment of Fig. 7 can be adapted to work with the embodiments disclosed in Fig. 3 and Fig. 5 also.
In yet another embodiment of the subject matter as described in Fig, 8, the pulley is a split type controlled pulley 240 whose mean operating radius could be altered depending on whether the requirement is of power transmission to the engine or of freewheeling after the engine has been fired. In the present embodiment, the controlled

pulley 240 is on the motor side whereas the controlling pulley (not shown in the figure) is on the engine side. The controlled pulley 240 is coupled to the sleeve 150 of the roller clutch 146. The controlled pulley 240 is coupled to the controlling pulley by means of a belt. The mean operating radius of the controlling pulley, on the engine side, is varied thereby varying the mean operating radius of the controlled pulley 240. A first cone 242 of the controlled pulley 240 is stationary whereas a second cone 244 of the controlled pulley 240 slides axially. The embodiment of Fig. 8 can be adapted to work with the embodiments disclosed in Figs. 3 and Fig. 5 also.
The previously described versions of the subject matter and its equivalent thereof have many advantages, including those which are described below. The cranking and firing time of the engine is reduced with reduced noise generation and the overrun abuse to the overrunning clutch is eliminated. Moreover, the utilization of a two stage epicyclic gear train enables to achieve a higher speed ratio. Also, the separation of the rollers of the roller clutch from the journal during normal running of the engine enables the elimination of the wear and tear of the rollers, thereby improving the performance of the roller clutch and the starting system.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

I / We claim:
1. A starting system for an internal combustion engine of a vehicle, said starting system comprising:
> a motor having a rotating armature shaft;
> a multiple stage speed reduction assembly comprising

• a first stage epicyclic gear train coupled to said armature shaft, said first stage epicyclic gear train having a first stage output shaft, and
• a second stage epicyclic gear train coupled to said first stage output shaft, said second stage epicyclic gear train having a second stage output shaft;
> a power transmission assembly comprising
• a journal member,
• a sleeve member,
• one or more one-way torque transmitting elements; and
> a power transmission member for transmitting power from said motor to
said engine,
characterized in that
said journal member is coupled to said second stage output shaft, said sleeve member encompasses said journal member, said torque transmitting elements are secured between said journal member and said sleeve member, and said power transmission member is rotationally coupled to said sleeve member, wherein said

torque transmitting elements lose contact with said journal member on firing of said engine and when the engine speed is above predetermined value.
2. The starting system as claimed in claim 1, wherein said epicyclic gear train comprises a sun gear, a stationary annulus and one or more planetary gears, and wherein said annulus is common for said first stage epicyclic gear train and said second stage epicyclic gear train.
3. The starting system as claimed in claim 1, wherein said armature shaft is supported inside a flanged first end of said first stage output shaft through a bearing.
4. The starting system as claimed in claim 1, wherein a second end of said first stage output shaft is supported inside a flanged first end of said second stage output shaft through a bearing.
5. The starting system as claimed in claim 1, wherein a second end of said second stage output shaft is supported inside a first end of said sleeve through a bearing.
6. A starting system for an internal combustion engine of a vehicle, said starting system comprising:

> an motor having a rotating armature shaft;
> a speed reduction assembly comprising

• a worm coupled to said armature shaft,
• a worm gear engaging with said worm, and
• an output shaft coupled to said worm gear; and
> a power transmission assembly comprising
• a j ournal member,

• a sleeve member,
• one or more one-way torque transmitting elements; and
> a power transmission member for transmitting power from said motor to said engine, characterized in that
said journal member is coupled to said output shaft, said sleeve member encompasses said journal member, said torque transmitting elements are secured between said journal member and said sleeve member, and said power transmission member is rotationally coupled to said sleeve member, wherein said torque transmitting elements lose contact with said journal member on firing of said engine.
7. The starting system as claimed in claim 1 or 6, wherein said motor and said speed reduction assembly are accommodated within a single housing.
8. The starting system as claimed in claim 1 or 6, wherein said one-way torque transmitting elements are rollers.
9. The starting system as claimed in claim 1 or 6, wherein said power transmission member is a pulley or a split type controlling pulley or a split type controlled pulley.
10. The starting system as claimed in claim 1 or 6, wherein power from said power transmission member is transmitted to said engine by means of a belt.
11. The starting system as claimed in claim 1 or 6, wherein said power transmission member is coupled to an overhanging end of said sleeve member.
12. The starting system as claimed in claim 1 or 6, wherein said power transmission assembly and the power transmission member are integral.

13. The starting system as claimed in claim 1 or 6, wherein an axis of said motor is
collinear with an axis of said speed reduction assembly.
14. The starting system as claimed in claim 1 or 6, wherein an axis of said motor is
inclined to an axis of said speed reduction assembly.
15. The starting system as claimed in any of claim 1 to 14, wherein said motor is a
brushed DC motor or a brushless DC motor or switched reluctance motor or