What is helical gear features and used for?

What is helical gear features and used for?

    Gear is a common part often used in mechanical transmission. The gear is made of high-quality high-strength alloy steel, surface carburized and hardened, with strong bearing capacity and durability. In practical applications, helical gears are widely used in high-speed and heavy-duty occasions due to their stable transmission, low impact, vibration and noise.
     Helical gears are not completely helical gears. It should be said that helical gears are the meshing method of two helical gears, which are distinguished by the different directions in which they transmit force in space. Ordinary spur gears mesh along the tooth width at the same time, resulting in shock vibration noise and unstable transmission. The helical spur gear transmission is better than the spur gear, and can be used for high-speed heavy loads with a compact center distance. The helical gear reducer is a novel reduction transmission device. Adopting the advanced design concept of optimization and modular combination system, it has the advantages of small size, light weight, large transmission torque, stable starting, and finely graded transmission ratio. It can be connected arbitrarily and various installation positions can be selected according to user requirements.

     There are many types of gear transmission, among which the efficiency of helical spur gears is very high. For example, the transmission efficiency of spur spur gears is lower than that of helical spur gears. Like the spur gear mechanism, the helical spur gear can be used for high-speed operation by reducing the center distance a so as to improve the carrying capacity of the transmission. The helical gear reducer is a novel reduction transmission device. The helical gear reducer is small in size, light in weight, and economical.

Basic parameters:
1. Helix angle: It refers to the angle between the teeth of the helical gear and the axis.
    The helix angle is a characteristic characteristic of helical gears and does not exist in spur gears, that is, spur gears. Generally speaking, the helix angle of the helical gear we usually refer to refers to the helix angle on the indexing cylindrical surface. The larger the helix angle, the greater the degree of overlap, which is more conducive to smooth movement and noise reduction. Everything is two-sided. Although increasing the helix angle brings many advantages, the axial force generated during operation also increases, so The size should depend on the quality requirements and processing accuracy of the work, generally 8-25, if there are special requirements for noise, the larger value can be taken according to the situation.
    Judgment of the direction of rotation of the helix: First, we make the axis of the gear vertical, if the height of the right side of the helix is ​​right-handed; otherwise, the height of the left side of the helix is ​​left-handed.
2. End face and normal face parameters:
End face: the plane perpendicular to the gear axis, the parameters on the end face are generally subscripted t;
Normal surface: the plane perpendicular to the helix, the parameters on the normal surface are generally subscripted n.
(1) Pitch and modulus: =t=π
(2) Pressure angle: the parameters in the normal plane are generally stipulated as standard parameters.
a. Correct meshing conditions: the helix angles must be equal in size and opposite in direction. The normal modulus m and the normal pressure angle are required to be equal respectively.
b. Calculation of geometric dimensions: The calculation formula of spur gears can be directly applied to the end face of helical gears because a pair of helical gear transmissions are equivalent to a pair of spur gear transmissions on the end plane.

Advantages and disadvantages
(1) Good meshing performance: The meshing process between the teeth of the helical cylindrical gear is an excessive process, and the force on the teeth is gradually increased from small to large, and then from large to small; helical gears are suitable for high-speed, overload situation.
(2) The degree of coincidence is large: the increase of the degree of coincidence increases the bearing capacity of the gear. Thus extending the life of the gear. The degree of coincidence mainly depends on the meshing time, and the helical gear has a long meshing time and a large contact area, which reduces the stress. And make the transmission smooth and increase its economy.
(3) Compact structure: the smaller the minimum number of teeth, the more compact the structure.
Disadvantages and corrections:
     Herringbone gears are more troublesome to manufacture.
     Axial force components are detrimental to gearing, increasing friction between devices, making them susceptible to wear or damage. The only disadvantage of helical gears is that an axial component force will be generated when the gears mesh. The axial force is caused by the helix angle, and the larger the helix angle, the greater the axial force. In order to prevent the helical gear from generating excessive axial force, it is generally taken as = 8 to 15 in the design.

The herringbone gear can reduce the influence of the axial component force, but the herringbone gear is more troublesome to manufacture. Uneconomical.
    The helical gear drive is composed of two helical gears meshing with each other.
Purpose: to transmit motion between two phase-staggered axes in space.

(1) The helical direction can change the center distance and transmission ratio;
(2) The steering can be changed by the helical change;
(3) Fast wear;
(4) point contact;
(5) The axial force is small.

    The helical gear reducer is a novel reduction transmission device. It has many advantages, such as small size and light weight. Due to the optimized cash design concept, the advantages of each performance are weighted and averaged to complement each other. The transmitted torque is increased, the transmission ratio is finely graded, the bearing capacity is enhanced, the use is durable, and the economy is good.
1. Involute helical gear reducer
    The involute helical gear reducer has the characteristics of small size, light weight, high bearing capacity, high efficiency, long service life, convenient installation, wide range of motor power, and fine classification of transmission ratio. It can be widely used in equipment that needs to be decelerated in various industries.
2. Helical gear worm gear reducer
    The helical gear worm gear reducer adopts the form of direct motor connection, and the structure is a first-stage helical gear and a first-stage worm gear transmission. The output is shaft mounted with six basic mounting styles. It can run forward and reverse. The helical gear adopts hard tooth surface, which has stable operation and large bearing capacity. The working environment temperature is -10℃~40℃. Compared with similar products, this product has the characteristics of large speed change range, compact structure and convenient installation. Can be widely used in metallurgy, mining, lifting, light industry, chemical industry, transportation, construction and other mechanical equipment deceleration mechanism.

    The meshing line of a spur gear is a parallel line, and its advantages are simple processing and no axial component force, but it has poor stability and vibration; the meshing line of a helical gear is an oblique line, which is difficult to process and has axial force, but is stable Good sex, small vibration [2].
    Helical gears are the most commonly used type of automotive power transmission gears, and generally have to work under high-speed and heavy-load conditions while requiring less vibration and noise. To improve their dynamic performance at high speed and reduce vibration and noise, tooth profile modification has become a necessary design and process means.
    There are two ways to modify the helical gear tooth profile, as shown in Figure 1.
    a is oblique modification, that is, the modified tooth surface is along the direction of the tooth surface contact line. This type of modification has no essential difference from the spur gear in the calculation method, but requires that the modified surface and the involute surface be tangent along the contact line, which is difficult to guarantee in terms of technology.
    b is a straight modification, that is, the modified surface is parallel to the tooth direction, and the entire tooth surface can be processed into a smooth surface in technology. However, since the contact line of the tooth surface of the helical gear is inclined, the straight modification will change the load distribution along the contact line, and even become a non-full-length contact, thereby changing the coincidence degree and the load distribution between the teeth, making the traditional gear modification calculation method. If it fails, the difficulty of its modification design is greatly increased.