WO2019003236A1

WO2019003236A1 - Double structure synchronizer ring and method of manufacturing thereof

Info

Publication number: WO2019003236A1
Application number: PCT/IN2017/050455
Authority: WO
Inventors: Vishal MAKWANA
Original assignee: Texspin Bearings Limited
Priority date: 2017-06-28
Filing date: 2017-10-06
Publication date: 2019-01-03

Abstract

A double structure synchronizer ring (1) mainly comprises of a synchronizer body (11) and Cu-Zn friction surface (12d). Said synchronizer body (11) is made from stamped steel, forged steel, cast steel or sintered steel. Said Cu-Zn friction surface (12d) is made from strip, ring or pipe of Cu-Zn alloy. Said Cu-Zn friction surface (12d) provides friction property where Synchronizer body (11) of steel provides strength. Said Cu-Zn friction surface (12d) is pressed with synchronizer (11) with die and punch to fix said Cu-Zn friction surface (12d) and synchronizer body (11) mechanically and obtain present invention.

Description

"DOUBLE STRUCTURE SYNCHRONIZER RING AND METHOD OF MANUFACTURING THEREOF"

FIELD OF THE INVENTION:

The present invention relates to a double structure synchronizer ring and a method for manufacturing it. More particularly, the present invention relates to a mechanically combined brass-steel synchronizer ring, such that the synchronizer possess high structural strength, light in weight, easy to manufacture and is cost effective. Moreover, the obtained light weight synchronizer achieves the requisite decrease in moment of inertia and decreased requirement of shifting force while synchronization. The process is also highly consistent and provides a high production rate.

BACKGROUND OF THE INVENTION:

The manual transmission gear box is generally provided in all automobiles with manual transmission and automatic manual transmission for providing different speed and torque to the moving automobile as per the requirement of driving condition. A Gear box comprises of more than three gear pairs for decreasing or increasing speed of the vehicle. In order to change the speed of vehicle, gear engaged with the output shaft must be altered with nearby gear. This process of altering gears is called synchronization. To achieve this, synchronizer ring are used in manual transmission gear box.

The transmission system of the gears plays an important role in determining the behavior of automobile with respect to gear shift comfort. Said Synchronizer mechanisms are provided for the smooth and noiseless synchronization while gear shift. The key characteristics required for the synchronizer ring to function effectively are: (i) that the coefficient of dynamic friction with respect to a mating member is large in order to synchronize two gears by frictionally engaging a tapered portion which is the mating member, and (ii) that the synchronizer ring has high wear resistance, i.e., sufficient mechanical strength and anti-abrasion characteristic in sliding with the mating member.

There are three different types of synchronizer ring, according to number of friction surfaces they possess, that are in common use i.e., i) single cone which have only one ring with only one friction surface (see Fig.1), ii) double cone which have an assembly of three rings with two friction surfaces and iii) triple cone having three rings assembly with three friction surfaces. i) Single cone synchronizer ring:

Said ring comprises of a single ring with one friction surface, and is used when torque difference between synchronizing gears is small and requirement of shifting comfort is less. ii) Double cone synchronizer ring:

Said synchronizer ring comprises of three rings with total of two friction surfaces comprising of outer ring and inner ring with one friction surface, or intermediate ring with two friction surfaces, and is used when torque difference between synchronizing gears is medium and requirement of shifting comfort is needed. iii) Triple cone synchronizer ring: Said synchronizer ring comprises of three rings with total three friction surfaces further comprising of outer ring with one friction surface and inner ring with two friction surface, and is used when torque difference between synchronizing gear is high and requirement of shifting comfort is high.

In manual transmission gear box the selection of type of synchronizer ring is based on torque difference between mating component and requirement of shifting comfort.

Popularly used conventional single cone synchronizer ring 1A is as shown in Fig. 1. The single cone synchronizer developed so far, widely available and popularly used establishes a requisite of synchronizer rings to be made of frictional material; wherein mostly with Brass (Cu-Zn alloy) is used to obtain good frictional property.

Referring Fig.1 said conventional synchronizer ring 1A are preferably made from forging, wherein said conventional synchronizer ring 1A comprises of: outer face 102, plurality of teeth 101, an inner face 103, lugs 104, annular grooves 105, axial grooves 106. Said inner face 103 is provided for contacting the gear cone. Said plurality of teeth 101 are provided at a predetermined interval to the extreme outer periphery of conventional synchronizer ring 1A. Said lugs 104 are for engaging with slot of corresponding member. To the inner face 103 of the conventional synchronizer ring 1A a plurality of annular grooves 105 are provided for applying friction force. Further, said axial grooves 106 are provided, for allowing drainage of lubricating oil. Said annular grooves 105 and axial grooves 106 are provided by machining process. At the time of synchronization said plurality of teeth 101 are subjected to shifting force applied by mating member and are in friction with mating member in order to synchronize the speed of gear. The lugs 104 are subjected to the tangential force from mating member while synchronization, that is why plurality of teeth 101 of synchronizer needs to be strong enough to withstand load applied while synchronization and should be wear resistant as there is frictional movement between synchronizer 1A and mating part. The single cone synchronizer rings are preferably made from hot forging of brass since these are stronger than those obtained from castings. Further in order to obtain the requisite strength of the synchronizer ring conventional methods uses hot forging process. However, Hot forging process is not consistent as this process includes shrinkages of materials.

Furthermore conventional ring comprises of annular and axial grooves made through machining which is a time consuming process.

However, the conventional synchronizer rings are entirely made from brass thereby making it bulky. Also brass not being heat -treatable material the wear resistant property of the conventional synchronizer ring of brass is poor which in turn wear out the teeth 101 of synchronizer ring. The strength of brass is less and it also cannot tolerate heat treatment and thereby fails to provide strength to the synchronizer ring. The larger size of the synchronizer ring is required in order to attain the required strength which thereby makes it bulky and imparts more moment of inertia which results in higher shifting force. Further, the synchronizer ring made entirely from Cu-Zn alloy has to offer high strength and high friction force, which implies there is balance between mechanical and frictional property. In order to improve frictional property, it is necessary to compromise on strength of synchronizer ring.

There were many categories, according to material, of synchronizer ring popularly available in industry as listed below:

1. Brass

2. Sintered steel

3. Sintered steel and brass

4. Steel and molybdenum coating

5. Steel and fiber coating There were many types of heat treatment available to improve strength and anti-abrasion characteristics of steel component in turns of hardness of components as per requirement:

1. Through hardening

2. Case carburizing

3. Carbo-nitriding

4. Induction hardening

5. Anodizing

PRIOR ART:

1. US patent 4267912 granted to Borg- Warner- Stieber describes the fiber coating on annular body of synchronizer ring by cementing. Fiber coating imparts good friction property. However, this device limited to induction hardening and anodizing type of synchronizer. Moreover, this device has occasional issue of peeling of fiber coating as it is cemented on annular body. Further, this device does not allow any machining process after coating to get final accurate dimension. Furthermore, fiber coating is very expensive, which makes the product expensive. US patent 6014807 granted to Hyundai Motor Company of Korea describes a double-structure synchronizer ring using copper powder sintering agent, to provide frictional property with an external ring body portion comprising sintering metal. The sintered synchronizer ring heat treatable by only anodizing process as its temperature is lower compare to any other heat treatment. Further machining operation is not possible after sintering to achieve final required dimensions. However this invention comprises sintering process which is complex and relatively expensive. US patent 4091904 describes wear-resistant, molybdenum sprayed on to one of the friction cone ring members whereas the other friction cone member has a manganese-alloyed carbon steel sprayed thereon. However, only induction hardening is possible on this device. Moreover, products of this invention have occasional issue of peeling of molybdenum coating and expensive to manufacture. US patent 4679681 describes a double structure synchronizer ring formed from composite material, which is made by roll cladding two metals. However invention is not generally used in practice as there is particular material can be cladded by roll cladding process. Further no heat treatment can be done to provide strength and anti-abrasion property in turns of hardness. DISADVANTAGES OF PRIOR ART:

The prior art suffers from all or at least any of the following

disadvantages :

• Brass Synchronizer Ring:

1. Brass cannot be heat-treated that is why to provide strength and anti-abrasion property ring should be large enough. This makes synchronizer ring bulky, which in turns increase moment of inertia, thereby increase the shifting force.

2. Brass has poor wear resistant property that is its teeth gets wear out in short time.

3. Made from hot forging process, which is not consistent process as this includes shrinkages of material.

4. It comprises of machining process, which is time consuming and is expensive.

· Sintered Steel Synchronizer ring:

1. No friction surface is there.

• Steel and brass synchronizer ring by sintering:

1. This synchronizer rings can only be subjected to anodizing type of heat- treatment process.

2. Further machining not possible after sintering to achieve final accurate dimensions.

3. Method of manufacturing is complex and expensive.

• Steel with molybdenum coating synchronizer ring:

1. This synchronizer ring can only be subjected to induction hardening process.

2. Products of this invention have occasional issue of peeling of molybdenum coating. 3. Further machining not possible after coating to achieve final accurate dimensions.

4. Product is expensive to manufacture.

5. Shift quality is not adequate.

· Steel with fiber coating synchronizer ring:

1. Very expensive to manufacture.

2. Has occasional issue of peeling of fiber coating.

3. Further machining not possible after fiber coating to achieve final accurate dimensions.

Thus there is an unmet need to come up with the invention that obviates the problem of prior art.

OBJECTS OF THE PRESENT INVENTION:

The main object of the present invention is to provide a double structure synchronizer ring and a method to manufacture said ring.

Another object of the present invention is to provide a double structure synchronizer ring and method to manufacture said ring, wherein the obtained light weight synchronizer achieves the requisite decrease in moment of inertia and decreased requirement of shifting force while synchronization. Still another object of the present invention is to provide a double structure synchronizer ring and method to manufacture said ring, wherein said synchronizer ring is heat treated by any type of heat treatment and further provides strength to the synchronizer ring. Still another object of the present invention is to provide provide a double structure synchronizer ring and a method to manufacture said ring that allows final finishing operations that includes machining and alike.

Still another object of the present invention is to provide a double structure synchronizer ring and a method to manufacture said ring that has a high production rate and is highly consistent.

Still further object of the present invention is to provide a double structure synchronizer ring and a method to manufacture said ring having axially extended grooves for drainage of lubricating oil.

Yet, the object of the present invention is to provide a double structure synchronizer ring and a method to manufacture said ring, having friction surface, thereby minimizing the complexity and cost of manufacturing operations.

Yet another object of the present invention is to provide a double structure synchronizer ring and a method to manufacture said ring, which improves the strength of synchronizer ring, thereby reducing weight and cost of synchronizer ring, without compromising the friction property of friction surface.

Further the object of present invention is to provide a double structure synchronizer ring and a method to manufacture said ring, wherein said ring made of double structure from which body made of steel, to provide structural strength, and friction surface made from friction material, to serve the purpose of friction force. Further, said friction surface not necessarily required to have structural strength, which allows to choose best friction material for the application without compromising on strength of synchronizer ring.

BRIEF DESCRIPTION OF THE DRAWINGS: The present invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various Figures. The embodiment/s herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein

Fig. 1 discloses the perspective view of the conventional synchronizer ring.

Fig. 2 shows the perspective view of the synchronizer ring of present invention.

Fig. 3 shows the perspective view of friction strip which is to be attach with synchronizer body.

Fig.4 shows the fragmentary view of first step of manufacturing of present invention to provide a friction surface by friction strip or ring.

Fig.5 shows perspective view and sectional view of first step of manufacturing of present invention to provide friction surface by friction strip of ring. Fig. 6 shows perspective view and sectional view of final step of manufacturing of present invention to provide friction surface by friction strip or cap.

Fig. 7 shows fragmented sectional view of another embodiment of present invention for double cone synchronizer. Fig. 8 shows sectional view of present improved synchronizer assembly illustrating embodiment of double cone synchronizer ring of present invention.

Fig. 9 shows fragmented sectional view of another embodiment of present invention for triple cone synchronizer.

Fig. 10 shows sectional view of present improved synchronizer assembly illustrating embodiment of triple cone synchronizer ring of present invention.

References used for the parts of the present invention illustrated in drawings:

1 Present Synchronizer ring

1A Conventional Synchronizer ring

2 Double cone synchronizer ring

3 Triple cone synchronizer ring

101 Plurality of teeth

102 Outer face

103 Inner face

104 Lugs

105 Annular grooves

106 Axial grooves

11 Steel Synchronizer body

111 Plurality of teeth

112 Outer Face

113 Axial grooves

114 Inner face

12a Cu-Zn Friction strip 12b Cu-Zn Friction ring

12c Cu-Zn Friction strip after bending

12d Cu-Zn Friction strip after forming process

121 Flange

122 Axial streaks

123 Axial grooves formed in friction ring

13A Intermediate ring

14 Inner ring of double cone synchronizer

15 Cu-Zn Friction strip

16 Inner ring of triple cone synchronizer

17 Cu- Zn Friction cap

DETAILED DESCRIPTION OF THE PRESENT INVENTION:

The present invention provides a double structure synchronizer ring a method to manufacture said ring. More particularly, the present invention relates to a mechanically combined brass-steel synchronizer ring, such that the synchronizer possess high structural strength, light in weight, easy to manufacture, highly consistent and is cost effective. Moreover, the obtained light weight synchronizer achieves the requisite decrease in moment of inertia and decreased requirement of shifting force while synchronization. The process also provides a high production rate.

Said invention mainly comprises of:

• Steel Synchronizer body 11

• Plurality of teeth 111

• Outer Face 112

• Axial grooves 113

• Inner face 114 • Cu-Zn Friction strip 12a

• Cu-Zn Friction ring 12b

• Cu-Zn Friction ring with flange 12c

• Cu-Zn Friction surface after forming 12d

• Flange 121

• Axial streaks 122

• Axial grooves formed in friction ring 123

Said Cu-Zn friction surface 12d provides friction to the present invention and is therefore also referred as friction surface herein after.

Said steel synchronizer body 11 made up of stamped steel, cast steel, sinter steel or forged steel is provided to engage with teeth of shifter, and said Cu-Zn friction surface 12d made up of friction strip 12a or friction ring 12b, and is provided to be in contact with gear cone. In said hybrid structure, the steel synchronizer body 11 provides structural strength of rigidity whereas Cu-Zn friction surface 12d provides friction to the present double structure synchronizer ring 1. Further said friction surface 12d can be made of any material which imparts high friction force. Referring to Fig.4, axial grooves 113 on said steel synchronizer body 11 of a synchronizer ring 1 is provided to constrain the relative rotation of synchronizer body 11 and friction surface 12d. The Number of axial groove 113 depends on torque capacity of synchronizer ring 1 i.e., higher the torque capacity the more number of axial grooves 113 required.

The method of mechanical fixing the present assembly involves following points: Step 1: In order to obtain the said hybrid structure, said steel synchronizer body 11 and said Cu-Zn friction ring 12c, made from Cu-Zn friction strip 12a or Cu-Zn friction ring 12b or pipe of Cu-Zn alloy, which comprises of flange 121 as shown in Fig. 4.

Step 2: Referring to Fig.5 said Cu-Zn friction ring 12c is inserted in steel synchronizer body 11 such that their relative axial movement in one direction gets constrain by flange 121 of Cu-Zn friction surface 12c.

Step 3: In order to obtain the said hybrid structure, said steel synchronizer body 11 and friction strip 12c are pressed with the help of die and punch to match the angle of outer face of Cu-Zn friction surface 12d with angle of inner face of synchronizer body 11, thereby constrains the axial and radial movement of synchronizer body 11 with respect to Cu-Zn friction surface 12d as shown in Fig. 6. Further a punch is provide to the said hybrid structure such that it protruded axially extended streaks and bulge penetrate in friction surface 12d to provide axially embossed streaks 122 and axial grooves 123, to provide friction force on gear cone and means of drainage of lubricating oil as shown in Fig. 6.

FURTHER EMBODIMENTS OF PRESENT INVENTION: A. Fig. 7 shows the double structure double cone synchronizer ring 2. The double cone synchronizer 2 has two friction surfaces. One on outer ring 11 and other on outer face of inner ring 14. As shown in Fig. 7 double structure double cone synchronizer ring 2 comprises of: a. An steel synchronizer body 11, made of stamped steel, cast steel, sinter steel or forged steel, with Cu-Zn friction surface 12d,

b. A conventional intermediate ring 13A made of stamped steel, cast steel, sinter steel or forged steel and

c. An improved Inner ring of double cone synchronizer 14, made of stamped steel, cast steel, sinter steel or forged steel, with outer Cu-Zn friction strip 15. The steps involved in mechanical joining method of outer Cu-

Zn friction surface 15 with improved Inner ring 14, of double cone synchronizer, by press operation is same as described in description of main embodiment. Fig. 9 shows the double structure double cone synchronizer ring 3. The double cone synchronizer 3 has two friction surfaces. One on outer ring 11 and other two on inner ring 14. As shown in Fig. 9 the double structure triple cone synchronizer ring 3 comprises of: a. Steel synchronizer body 11, made of stamped steel, cast steel, sinter steel or forged steel, with Cu-Zn friction surface 12d,

b. A convention intermediate ring 13A made of stamped steel, cast steel, sinter steel or forged steel and

c. An improved Inner ring of triple cone synchronizer 16 for triple cone synchronizer, made of stamped steel, cast steel, sinter steel or forged steel, with Cu-Zn friction cap 17 that provides frictional surfaces on both sides. The steps involved in mechanical joining method of friction cap 17 and improved inner body 16, of triple cone synchronizer, by press operation is same as described in description of main embodiment.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and /or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

ADVANTAGES OF THE INVENTION:

There are many advantages of the present invention over prior art:

• Present invention provides double structure synchronizer ring with high strength, anti-abrasion and friction.

• It replaces the annular grooves with axially formed streaks, and thereby increases the productivity as machining time is excluded.

• It provides consistent double structure synchronizer ring.

· It allows final finishing operations that include machining and alike. • Synchronizer ring of present invention heat treated by any heat treatment as per requirement of application.

• Present invention provides the method of manufacturing synchronizer ring, which is highly consistent and have high production rate.

• It allows choosing the best friction material for the application without compromising on strength of synchronizer.

• It reduces the weight.

• It is economical.

Claims

CLAIMS:

1. Present Double Structure Synchronizer Ring And Method Of Manufacturing Thereof wherein, said invention mainly comprises of:

o Steel Synchronizer body 11,

o Plurality of teeth 1 11,

o Outer Face 112,

o Axial grooves 113,

o Inner face 114,

o Cu-Zn Friction strip 12a,

o Cu-Zn Friction ringl2b,

o Cu-Zn Friction surface after forming

flange 12c,

o Cu-Zn Friction surface after bending

12d,

o Flange 121,

o Axial streaks 122,

o Axial grooves formed in friction ring 123;

wherein; said steel synchronizer body 11 is provided to engage with teeth of shifter, and said Cu-Zn friction surface 12d made up of friction strip 12a or friction ring 12b, and is provided to be in contact with gear cone; in said hybrid structure, the steel synchronizer body 11 provides structural strength of rigidity whereas Cu-Zn friction surface 12d provides friction force to the present double structure synchronizer ring 1; further said Cu-Zn friction surface 12d provides high frictional force on corresponding synchronizer components; said steel synchronizer body 1 1 of a synchronizer ring 1 is made from forged steel, cast steel, sintered steel or stamped steel with axial grooves 113 formed in it and is provided to constrain the relative rotation of synchronizer body and friction surface 12d; the Number of axial groove 113 depends on torque capacity of synchronizer ring 1, higher the torque capacity the more number of axial grooves 113 required; wherein further the method for manufacturing said double structure synchronizer ring comprises of steps; a. in order to obtain the said hybrid structure, said Cu-Zn friction surface 12c made from Cu-Zn friction strip 12a or Cu-Zn friction ring 12b or pipe of Cu-Zn alloy, which comprises of flange 121; b. said Cu-Zn friction ring 12c is inserted in steel synchronizer body 11 such that their relative axial movement in one direction gets constrain by flange 121 of Cu-Zn friction surface 12c; c. said steel synchronizer body 11 and friction strip 12c are pressed with the help of die and punch to match the angle of outer face of Cu-Zn friction surface 12d with angle of inner face of synchronizer body 11, thereby constrains the axial and radial movement of inner body with respect to outer body; further a punch is so designed that it protrudes axially extended streaks and bulge penetrate in friction surface 12d to provide axially embossed streaks 122 and axial grooves 123, to provide friction force on gear cone and means of drainage of lubricating oil. Present Double Structure Synchronizer Ring And Method Of Manufacturing Thereof as claimed in claim 1 , wherein said double structure double cone synchronizer ring 2 comprises of: o an steel synchronizer body 11, made of stamped steel, cast steel, sinter steel or forged steel, with Cu-Zn friction surface 12d,

o a conventional intermediate ring 13A made of stamped steel, cast steel, sinter steel or forged steel and

o an improved Inner ring of double cone synchronizer 14, made of stamped steel, cast steel, sinter steel or forged steel, with outer Cu-Zn friction strip 15 which provides friction surface on outer face of inner ring 14; wherein the steps involved in mechanical joining method of outer Cu-Zn friction strip 15 with improved Inner ring of double cone synchronizer 14, of double cone synchronizer, are same as claimed in point a to c of claim 1.

Present Double Structure Synchronizer Ring And Method Of Manufacturing Thereof as claimed in claim 1 and claim 2, wherein said double structure triple cone synchronizer ring 3 comprises of: o steel synchronizer body 11 , made of stamped steel, cast steel, sinter steel or forged steel, with Cu-Zn friction surface 12d,

o a convention intermediate ring 13A made of stamped steel, cast steel, sinter steel or forged steel and

o an improved Inner ring of triple cone synchronizer 16 for triple cone synchronizer, made of stamped steel, cast steel, sinter steel or forged steel, with Cu-Zn friction cap 17 that provides frictional surfaces on both sides; wherein the steps involved in mechanical joining method of Cu-Zn friction cap 17 with improved Inner ring of triple cone synchronizer 16 for triple cone synchronizer by press operation is same as claimed in point a to c of claim 1.