Rigid harmonic gear mechanism providing high conversion ratio in involute profile structure

Abstract

The invention relates to the mass manufacturing of the involute profile, which enables the gear wheels to adapt to each other efficiently and creating low levels of vibration and noise during power transmission, with profile modification to enable harmonic movement.

Description

[0001] RIGID HARMONIC GEAR MECHANISM PROVIDING HIGH CONVERSION RATIO IN INVOLUTE PROFILE STRUCTURE

[0002] Technical Field

[0003] The invention relates to the mass manufacturing of the involute profile, which enables the gear wheels to adapt to each other efficiently and creating low levels of vibration and noise during power transmission, with profile modification to enable harmonic movement.

[0004] Prior Art

[0005] Nowadays, gear mechanisms are an indispensable part of industrial applications, and the design of these mechanisms is made to meet the requirements of high efficiency, minimum loss and optimum gear ratio. The design of tooth structures is based on suitability for mass manufacturing conditions and manufacturing counters used. In this context, the main reason why the involute tooth profile is preferred is that this profile is based on the rolling of a line on a circle and, accordingly, the advantages it provides in the interaction of gear wheels with each other. Involute profile provides minimum slip, maximum efficiency and full cycle rate transmission. In this way, involute profiles become an ideal choice for ordinary and planetary gear mechanisms.

[0006] In the state of the art, the use of cycloid profiles also comes to the fore in special embodiments that require harmonic motion. Due to the nature of the mechanism, the cycloid profile creates an ideal structure to prevent locking during rotation both around its own axis and around another tooth. However, the manufacturing of cycloidal gears is a process that requires complex design and high precision. Cycloidal gear type can be produced not by traditional manufacturing methods such as hobbing and form milling, but on special manufacturing machines such as CNC milling machines with four axis. For this reason, the manufacturing process of cycloid gear becomes long and complex.

[0007] The gear mechanisms in the state of the art have limitations, especially in cases requiring high cycle rates. While a maximum of 8 gear ratio can be achieved in one stage, higher rates increase the size, cost and complexity of the mechanism. In order to overcome this problem in the state of the art, innovative solutions such as the harmonic drive mechanism designed by CW Musser in 1959 have been developed. The harmonic drive provides high gear ratios by using a flexible external gear and a wave generator and offers a compact structure. However, flexible gear has disadvantages such as low strength and short life.

[0008] As a solution to the problems in the state of the art, cycloidal reducers (Cyclo Drive) using rigid gears in cycloidal form have been developed. These systems have the advantages of providing high ratio rate and power transfer with a single stage. However, the manufacturing of cycloidal reducers cannot become widespread due to their non-standard gear forms and complex manufacturing processes. In addition, the maintenance and repair processes of their gear systems are more complex compared to other existing gear manufacturing.

[0009] In the state of the prior art, in harmonic reducers, the gear with involute profile structure is made flexible to prevent tooth interference. The flexible gear undergoes deflection (change in shape) due to the tooth force acting on it and is crushed, preventing the teeth from interference.

[0010] The design and manufacturing of the gear mechanisms in the state of the art are constantly evolving to meet the requirements of high efficiency and optimum ratio. Involute and cycloid tooth profiles play important roles in meeting these needs, and each has its own advantages and application areas. These technological advances emphasise the importance of R.&D studies to make mechanical systems more efficient, compact and cost-effective.

[0011] The Aim of the Invention

[0012] This invention differs from existing systems by redesigning the traditional involute gear structure to adapt to harmonic motion. The main aim of the invention is to create a rigid gear mechanism containing internal and external gears, compatible with traditional manufacturing methods of the involute profile, and to make this mechanism compatible with harmonic motion.

[0013] Three main modification methods given below are used to adapt the gear mechanism to harmonic motion; • changes made in the head part of the tooth profile,

[0014] • changing the pressure angle applied to the gear between 0-45° and

[0015] • with the profile shifting method, providing harmonic movement without interference, changing the distance between axes, increasing the contact ratio and tooth load carrying capacity are used.

[0016] Profile shifting has been found to be the most effective method in providing harmonic movement and can be applied on existing machining without the need for modification of the tools.

[0017] The subject of the invention shows that the eccentricity value that provides harmonic movement can change by using different module values and tooth number pairs, and in addition, the eccentricity distances and gear ratios obtained with different tooth ratios can also change. The pinion, called the inner gear, can theoretically be used infinitely side by side throughout the 360° ring gear angle, allowing power and torque to be increased.

[0018] Briefly stated, the subject of the invention is an involute gear mechanism composed of inflexible internal and external gears, developed with modifications suitable for harmonic motion. This system can provide high gear ratios and very high torque and power transmission in a single stage, compatible with the existing manufacturing infrastructure, and offers a compact and space-saving structure.

[0019] Detailed Description of the Invention

[0020] The shapes of the harmonic gear mechanism suitable for the aims of the invention are as follows;

[0021] Figure 1 - Front view of the harmonic gear mechanism of the invention

[0022] Figure 2 - Cross-sectional view of the harmonic gear mechanism of the invention

[0023] Figure 3 - Isometric view of the harmonic gear mechanism of the invention

[0024] The elements in the figures above are numbered as follows and these numbers will be used in the remainder of the description:

[0025] 1. Oil Plug

[0026] 2. Involute Profiled Rigid Pinion Gear 3. Body Gasket

[0027] 4. Oil Seal Cover

[0028] 5. Bearing

[0029] 6. Sealing felt

[0030] 7. Reducer Cover

[0031] 8. Bolt

[0032] 9. Involute Profiled Ring Gear

[0033] 10. Pin

[0034] 11. Oil Drain Plug

[0035] 12. Sealing felt

[0036] 13. Input Shaft

[0037] 14. Oil Seal Cover

[0038] 15. Bearing

[0039] 16. Reducer Output Shaft

[0040] 17. Bolt

[0041] 18. Reducer Cover

[0042] 19. Bolt

[0043] The subject of the invention consists of an involute profile ring gear (9) and an involute profile rigid pinion gear (2) in single stage, and is suitable for the use of all rigid materials such as steel, which are frequently used in reducer manufacturing, as well as the use of flexible materials in the state of the art. As seen in Figure - 2, it comprises at least one involute profile rigid pinion gear (2), at least 4 bearings (5), at least one input shaft (13), at least one reducer output shaft (16), two reducer covers (7), at least 4 bolts (8), at least 4 pins (10), at least 1 oil plug (1), at least 1 oil drain plug (11) and at least 2 bearing oil seals.

[0044] In the invention, the profile structure of the involute profiled rigid pinion gear (2) is modified in an involute manner and in accordance with the harmonic movement. The eccentricity determined as a result of the modification of the involute profile described above is the design element of the invention and is reshaped in each module and tooth structure. The involute profiled rigid pinion gear (2) offers higher power transmission capacity compared to the flexible gear and ease of calculation and manufacturing compared to the rigid cycloid gear. There are three profile modifications regarding the invention. The first of the profile modifications is to cut a maximum of 1 module above the graduated circle in the tooth profile. Modification of radius values in the tooth head section and modification of the clearance value at the tooth head are performed. Said first profile modification is applied by modifying the tools used in the machine structures in the state of the art. In the second profile modification, the value of the angle called the grip or pressure angle, which is applied as 20° in the standard, which is essentially the sharpening angle of the tool forming the involute profile, is changed and a new angle value is determined from the angle value range of 0 - 45°, making it capable of applying harmonic movement. In the third profile modification, the profile shifting application, which is applied in almost all gear mechanisms to maintain the distance between the axes, increase the gear ratio or increase the tooth load carrying capacity, is used to provide harmonic movement as a minimum of -1 and a maximum of +1 module.

[0045] The torque coming from the engine to the reducer shown in Figure 3 is made through the input shaft (13). The input shaft (13) provides ease of manufacturing and maintenance compared to eccentric bearings, and ease of use in rigid systems compared to the wave generator. Since the input shaft (13) in the reducer is eccentric, it transfers the torque on it to the pins (10) via the involute profiled rigid pinion gear (2) reducing the ratio determined by the number of teeth of both the involute profiled ring gear (9) and the involute profiled rigid pinion gear (2) by keeping the involute profiled ring gear (9) stationary. Involute profiled ring gear (9) offers ease of calculation and manufacturing compared to cycloid gear. The reducer output shaft (16) is the shaft to which the pins (10) that provide harmonic movement are connected. The torque coming to the reducer output shaft (16) through the pins (10) is also output from the reducer via the reducer output shaft (16) at a reduced speed. The eccentric input shaft (13) is one of the most critical parts of the harmonic reducer. Harmonic movement is achieved by means of the eccentric structure of the input shaft (13). In another embodiment of the invention, by keeping the pins (10) fixed, the input can be given through the involute profiled ring gear (9), and the output can be made from the reducer via the reducer output shaft (16).

[0046] The oil plug (1) seen in Figure 3 is used to replenish the system with oil. If desired, the oil in the system can be drained through the oil drain plug (11). The bearing (5) and the reducer input shaft (13) are connected to the involute profiled rigid pinion gear (2). The reducer cover (18), bearing (15) and bearing sealing felt (12) located on the inlet side of the reducer are mounted with the help of bolts (8). The involute profiled ring gear (9) is connected to the reducer cover (18) and the body gasket (3) via bolts (19). Bolts (8) are used to connect the reducer output shaft

[0047] (16) to the pins (10). Bolts (8) are used to connect the oil seal cover (4) on the output side of the reducer to the bearings (5) and to connect the 025 mm diameter bearing seal felt (6) to the said oil seal cover (4). The reducer output shaft (16) group and the reducer cover (7) group are assembled within themselves and are mounted to the body gasket (3) and the involute profiled ring gear (9) with bolts

[0048] (17) as shown in Figure - 1. The involute profiled rigid pinion gear (2) is placed inside the involute profiled ring gear (9). More than one (in theory, an infinite number) can be determined by extending the involute profiled ring gear (9) in length and positioning the involute profiled rigid pinion gears (2) side by side. Thus, with each gear contact, the load is divided and the power increased due to the torque transmitted.

Claims

CLAIMS1. Harmonic gear mechanism that adapts to the use of metal, composite materials, and flexible materials in reducer manufacturing, comprising:- involute profiled rigid pinion gear (2), profile structure of which has been modified in an involute shape and suitable for harmonic motion,- involute profile ring gear (9), whose width is determined by lengthening the said involute profile rigid pinion gears (2) and positioning them more than one side by side,- input shaft (13) which contributes to the harmonic movement by means of its eccentric structure by transferring the torque coming from the motor to said reducer, and- It contains the reducer output shaft (16), which is a shaft connected to the pins (10) that provide harmonic movement, and which enables the output from the said reducer by increasing the torque and decreasing its speed through the said pins (10).

2. Harmonic gear mechanism according to Claim 1, The involute profile rigid pinion gear (2) contains a pin (10) that transfers the torque by increasing the torque and decreasing the speed in proportion to the number of teeth.

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