WO2023096600A1

WO2023096600A1 - Development in the production process of synchromesh gear and the production mechanism of synchromesh gear applying this process

Info

Publication number: WO2023096600A1
Application number: PCT/TR2021/051609
Authority: WO
Inventors: Olgun TANBERK
Original assignee: Si̇nter Metal İmalat San. A.Ş.
Priority date: 2021-11-27
Filing date: 2021-12-29
Publication date: 2023-06-01

Abstract

The present invention relates to a mechanism that produces the synchromesh gears used in the transmissions of vehicles with the sintering method and to the production method of the synchromesh gear using sintering with this mechanism. Our mechanism comprises lower pressure section (2) that contains synchromesh gear mold (9) into which alloy steel powders are poured, A surface machining part (6) which processes the A surface of the synchromesh gear from the bottom and an upper pressure part (1) that contains A surface upper machining part (5) that processes the A surface of the synchromesh gear from the top, powder pressing adapter (8) for conical pressing of B surface which provides the formation of the conical B surface of the synchromesh gear and cylindrical part (10) with lateral walls that enable the synchromesh gear to be calibrated by pressing in a closed mold. Our inventive method comprises the following process steps; creating a closed mold environment by moving the upper pressure part (1) located in the upper part of our synchromesh gear production mechanism, towards the lower pressure part (2), which contains the mold filled with alloy steel powder inside the closed mold after alloy steel powders are poured into the synchronizer gear mold (9), calibrating the alloy steel powders in the synchromesh part mold (9) in the closed mold environment by heating and pressing them up to approximately 1200 °C, forming the A surface of the synchromesh gear by applying pressure with the A syrface upper machining part (5) located in the upper pressure part (1) and A surface bottom machining part (6) located in the lower pressure part (2), forming the conical B surface (4) of the synchromesh gear by applying a press to the alloy steel powder, which is in the mold and reaches up to about three quarters of its melting temperature, with the powder pressing adapter (8) for conical pressing of the B surface in the upper pressure part (1), taking A and B surfaces (3, 4) of the synchromesh gear from the press mold and subjecting the same to the sintering process directly after they are being formed.

Description

DEVELOPMENT IN THE PRODUCTION PROCESS OF

SYNCHROMESH GEAR AND THE PRODUCTION MECHANISM OF SYNCHROMESH GEAR APPLYING THIS PROCESS

Field of the Invention

The present invention relates to the development in the production process of synchromesh gear used in automobile transmissions and the production mechanism of synchromesh gear applying this process

Prior Art

As it is well known, the power generated by the engine in automobiles is transferred to the wheel through the transmission, which is also referred to as the gearbox. Synchromesh gears are used such that the gear wheels in the gearbox can transmit the movement in synchronization with each other during gear shifts. Synchromesh gears are exposed to high heat and stress due to frictions since they come into contact with the gear wheels inside the gearbox by activating during the gear change. Synchromesh gear requires both high strength and very precise manufacturing so as to transmit the movement to the gear wheel without loss. In case the precision is not high, the synchromesh gear cannot move synchronously with the gear wheels, it cannot transfer the movement to the gear wheels without loss during gear change since full engagement cannot be achieved, thus It causes loss of power to be transmitted to the wheel. When it continues to operate in this way, it damages the gear wheels and gearbox since the synchromesh gear must continue to operate in a synchronized way.

Synchromesh gears used in all vehicles today are manufactured by two methods. One of these methods is the production of the synchromesh gear from solid material or by processing all the dimensions after forging the drafts obtained by casting.

The second production method is the production of synchromesh gears from alloy steel powders by powder metallurgy method. Synchromesh gear is produced with all technical drawing details and sinter technology (pressing, sintering, calibrating) in this second production method. A and B surfaces of the raw synchromesh gear produced by this method are produced in a flat and raw manner, and then mechanically processed by a worker in a separate workbench so as to have micron level precision. After the sintering process of the synchromesh gear that is produced in a raw manner is completed, additional mechanical processes must be applied so as to give the synchromesh gear high precision thus it reduces the production per unit time, also causes the synchromesh gear to be very expensive. Well-known sintering technology is also used in our invention, however, there is no need for additional mechanical processing after the sintering process is completed so as to give precision to the A and B surfaces of the synchromesh gear. The process of sensitization of the synchromesh gear is included in the method with an improvement added to the existing known sintering apparatus. The synchromesh produced with the existing sintering technology becomes the final product directly without any processing with the developed pressing and calibrating methods with our invention. The production amount is greatly increased and the cost is greatly reduced by means of the inventive synchromesh gear assembly and the synchromesh gear produced with this assembly. In the trials we made; while 500 pieces of production can be made per day in the production of synchromesh gear with the prior art, the daily production amount of the synchromesh gear is increased up to 10,000 in series with our invention. It is sufficient for only one pressing operator to press and calibrate without the need for a worker who does mechanical processing so as to achieve this result. There is no need for 20 benches and 20 workers as in the prior art. All these advantages gained with our invention are provided by transferring the necessary form and sensitivity of the synchromesh gear, which was produced in a raw form after sintering, into the existing sintering process.

While the surface A of the synchromesh gear is indented, B surface is the conical surface of the synchromesh gear. A and B surfaces of the synchromesh gear is formed by pressing straight and vertically in the current sintering method. After A and B surface that are pressed flat and upright are exposed to sintering process, they are exposed to manual processing by the workers at the turning lathes and thus synchromesh gear with a sensitive structure is produced. When the synchromesh gear is not high precision, it is not possible to ensure that the gear wheels in the gearbox are synchronized with each other during the gear change, it cannot work in harmony with the gear wheels in the gearboxes, causing snagging.

Synchromesh gears, which are produced as raw after sintering, are taken to separate benches, then A surface is subjected to grinding and B surface is subjected to shaving or chip removal by the workers by mechanical processes, and they operate in synchronization with the gear wheels in the gearboxes of the vehicles. However, the knowledge, hand skill and concentration of the worker who applies the mechanical operation are very important in this manufacturing method so as to impart sensitivity to the raw-manufactured synchromesh gear. The deficiencies or a momentary lack of attention of the worker who applies the mechanical operation cause losses in the manufacture of synchromesh gears. The manufacture of the synchromesh gear with the state of the art is extremely difficult and expensive. For example, while the sintering cost of a synchromesh gear is 1 lira, a mechanical labor cost is also 1 lira. The mechanical labor required to give high precision to the synchromesh gear after sintering is completely eliminated with our invention which is the subject of the application.

Also, more material is used since the A and B surfaces of the synchromesh gear produced with the state of the art will be processed afterwards and it is required that they are produced flat with tolerance. The surfaces of the synchromesh gear, which is produced flat by leaving tolerance, must be subjected to turning process. While the cost of the synchromesh gear manufactured using the existing sintering method is one unit, the mechanical processing cost of the raw synchromesh gear is also one unit. If the required precision is not achieved, the gear will not operate in the synchronized use of the synchromesh gear in the gearbox (transmission).

One of the methods used in the production of synchromesh gear is the production method of the synchromesh gear mentioned in our patent application numbered TR 2018/06427. In this method, after the powder metal parts used in the production of the synchromesh gear are mixed in the specified proportions at normal ambient temperature, filled into the synchronizer gear mold and pressed, they are taken from the mold and transferred to the sinter furnace conveyor, nesting occurs due to the high temperature in the furnace, partial melting occurs between the powder particles in contact with each other. Therefore, there is a decrease in the spaces between these dust particles. In case the obtained parts do not comply with the desired standards after they are passed through quality control, they are calibrated by transferring the same to calibration presses. The produced synchromesh gear is subjected to CNC turning process so as to make more precise adjustments and to increase its resistance to heat caused by friction. In the production of synchromesh gear mentioned in this document, subjecting the same to processes such as CNC turning again increases production costs and causes loss of time and effort so as to increase the resistance against the heat caused by the friction on the surfaces in contact with the gear wheels in the gearbox.

The Difference of the Invention from the Prior Art and the Advantages of These Differences compared to the Prior Art:

The process of increasing the strength of the surfaces on which the synchromesh gears manufactured with the state of the art come into contact with the gear wheels in the gearbox during gear change is contained in the manufacturing method of the synchronizer gear with our invention. Thus, the production of synchromesh gears has been simplified, the manufacturing cost has been reduced and the manufacturing time has been shortened, and more precise synchromesh gear has been produced. Strength-increasing processing steps such as CNC turning are eliminated. In our invention, not only the strength of the surfaces contacted by the synchromesh gear is increased, but also the strength of other surfaces of the synchromesh gear can be increased.

After the synchromesh gear is produced raw with our invention, the process of forming and providing the necessary precision is carried out in series without human touch in the production of the synchromesh gear without the need to give the necessary form and precision by mechanical processing by the workers on separate benches. In this way, the production speed of the synchromesh gear is increased, then it is not exposed to mechanical processing by the workers in separate benches, thus it is possible to make mass production. Thus, loss of production during the processing of the raw synchromesh gears after sintering by the workers on the bench, to be experienced due to the carelessness of the worker or lack of hand skill is eliminated. After the synchromesh gear is produced as raw material after sintering, there is no need for separate benches for its processing. Therefore, less space can be sufficient for the production area of the synchromesh gear. It also saves in terms of labor and material cost.

Description of Figures

Figure- 1: Detail view of the powder filling system of the mechanism that produces the synchromesh gear using the sintering method in the prior art.

Figure-2: Detail view of the pressure system after the alloy steel powder is filled in the apparatus that produces raw synchromesh gears of the prior art.

Figure-3: Detail view of the caliber system that produces raw synchromesh gears of the prior art.

Figure-4: Detail view of the powder filling system of the mechanism that can produce the final synchromesh gear with precision using our inventive sintering method.

Figure-5: Detail view of the pressing system of the mechanism that can produce the final synchromesh gear with precision using our inventive sintering method.

Figure-6: Detail view of the caliber system of the mechanism that can produce the final synchronizer gear with precision using our inventive sintering method.

Figure-7: Sectional view of non-sensitive synchromesh gear produced with a prior art raw synchromesh gear mechanism

Figure-8: Cross-sectional view of the sensitive synchromesh gear produced with our inventive synchromesh gear mechanism. Figure-9: Top detail view of the sensitive synchromesh gear produced with our inventive synchromesh gear mechanism.

Figure- 10: Detail view from the bottom of the sensitive synchromesh gear produced with our inventive synchromesh gear mechanism.

Brief Definitions of Part Numbers in Figures:

1- Upper pressure section

2- Lower pressure section

3- Synchromesh gear A surface

4- Synchromesh gear B surface

5- A surface upper machining part

6- A surface bottom machining part

7- Powder filling cavity

8- B surface powder discharge adapter for conical pressure

9- Synchromesh gear mold

10- Cylindrical part with lateral walls that allows the synchromesh gear to be calibrated by pressing in a closed mold

Detailed Description of the Invention

The present invention relates to an improvement in the production method of the synchromesh gears used in the transmissions of the vehicles. Powder metallurgy method is used in our inventive production method.

Our invention relates to a mechanism that produces the final synchromesh with precision after manufacturing and the production method of the final synchromesh gear with this mechanism by applying the currently known sintering method and by making an improvement in the mechanism that produces raw synchromesh with flat A and B surfaces (3,4) (Figure-9) and later mechanically machined to gain sensitivity. In our inventive production method of the final synchronizer gear, after alloy steel powders are poured into the synchronizer gear mold, heat is applied up to about 1200 degrees, distortions occur in the synchromesh mold due to this heat. The synchromesh gear is calibrated by pressing in a closed mold so as to prevent the deterioration of the same due to heating. The compacting pressure mechanism located in the upper part of our synchromesh gear production mechanism moves towards the lower compacting pressure mechanism, where the mold filled with alloy steel powders inside the closed mold, applies a press during this process.

During this pressing process, the A surface machining part (5), one of which is in the upper pressure part, applies pressure so as to form the synchromesh gear A surface from the top, and A surface bottom machining part (6) applies pressure so as to machine the A surface from the bottom which is located in the lower pressure part. In this way, surface A of the final synchromesh gear (3) is formed.

B surface, located in the upper press section, presses the alloy steel powder in the mold, which reaches up to three quarters of its melting temperature, with the powder pressing adapter (8) for conical pressing so as to form the conical B surface (4) of our synchromesh gear. In this way, synchromesh gear B surface (4) is formed in a conical shape.

Alloyed steel powders in the synchromesh mold (9) in the lower pressure part (2) are pressed, for example, after 20 mm is filled and reduced to a depth of 10 mm and then produced to correspond to 7 gr/cc density.

After the A and B surfaces (3,4) of the synchromesh gear are formed, they are taken from the press mold (9) and subjected to the sintering process directly. It is subjected to cleaning with de-burring ceramic vibration after sintering. After the de-burring process, it is subjected to special calibration, after calibration, it is lubricated to increase its resistance to corrosion and then it is dried and subjected to the packaging process, and the manufacturing process is terminated. The mechanism that implements our inventive synchromesh gear production method is composed of two parts, the upper pressure section (1) and the lower pressure section (2).

In the lower pressure part (2); it comprises synchromesh gear mold (9) into which alloy steel powders are poured and A surface bottom machining part (6) that machines the synchromesh gear from the bottom. In the upper pressure part (1), it comprises A surface upper machining part (5), which processes the A surface of the synchronizer gear from above, powder pressing adapter (8) for conical pressing of B surface which provides the formation of the conical B surface (4) of the synchromesh gear and cylindrical part (10) with lateral walls that enable the synchromesh gear to be calibrated by pressing in a closed mold.

Claims

1. Mechanism that produces the synchromesh gears used in the transmissions of vehicles by sintering method, characterized in that; it comprises lower pressure section (2) that contains synchromesh gear mold (9) into which alloy steel powders are poured, A surface machining part (6) which processes the A surface of the synchromesh gear from the bottom and an upper pressure part (1) that contains A surface upper machining part (5) that processes the A surface of the synchromesh gear from the top, powder pressing adapter (8) for conical pressing of B surface which provides the formation of the conical B surface of the synchromesh gear and cylindrical part (10) with lateral walls that enable the synchromesh gear to be calibrated by pressing in a closed mold.

2. Mechanism that produces the synchromesh gears used in the transmissions of vehicles with the sintering method and to the production method of the synchromesh gear according to claim 1, characterized in that; it comprises the following process steps;

- creating a closed mold environment by moving the upper pressure part (1) located in the upper part of our synchromesh gear production mechanism, towards the lower pressure part (2), which contains the mold filled with alloy steel powder inside the closed mold after alloy steel powders are poured into the synchronizer gear mold (9),

- calibrating the alloy steel powders in the synchromesh part mold (9) in the closed mold environment by heating and pressing them up to approximately 1200 °C,

- forming the A surface of the synchromesh gear by applying pressure with the A surface upper machining part (5) located in the upper pressure part (1) and A surface bottom machining part (6) located in the lower pressure part (2),

- forming the conical B surface of the synchromesh gear by applying a press to the alloy steel powder, which is in the mold and reaches up to about three quarters of its melting temperature, with the powder pressing adapter (8) for conical pressing of the B surface in the upper pressure part (1),

- taking A and B surfaces of the synchromesh gear from the press mold and subjecting the same to the sintering process directly after they are being formed.

9

3- Production method of synchromesh gear according to claim 2, characterized in that; synchromesh part is subjected to cleaning with de-burring ceramic vibration after sintering.

4- Production method of synchromesh gear according to claim 2, characterized in that; it is subject to re-calibration after the de-burring process and is subject to lubrication to increase its resistance against corrosion.

5. Production method of synchromesh gear according to claim 3, characterized in that; it is subject to drying and packaging processes after the lubrication process.

6. Production method of synchromesh gear according to claim 1, characterized in that; alloyed steel powders in the synchromesh mold in the lower pressure part are pressed, for example, after 20 mm is filled and reduced to a depth of 10 mm and then produced to correspond to 7 gr/cc density.