What is the Advantage and Disadvantage of rv reducer

There are two main types of retarders widely used in joint robots: RV retarder and harmonic retarder. So, for these two reducer, which has the advantage? What are the principles, advantages and disadvantages of the two? Can they replace each other? Let's find out.

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Harmonic reducer is used for industrial robots with small loads, or several axes at the end of large robots, harmonic reducer for small robots are characterized by small size, light weight, large carrying capacity, high motion accuracy, and large single-stage transmission ratio.

The harmonic reducer is one of the harmonic transmission devices, and the harmonic transmission device includes an accelerator and a reducer. The main structure of harmonic reducer is rigid wheel, flexwheel, bearing and wave generator, all of which are indispensable. Among them, the number of teeth of the rigid wheel is slightly greater than the number of teeth of the flexible wheel.

RV reducer is often used in the robot joints with large torque, specifically the three joints of the leg waist and elbow, the load is large industrial robots, and the RV reducer is used in one, two and three axes. RV reducer compared with the harmonic reducer has higher fatigue strength, stiffness and life, the disadvantages of harmonic reducer also include, with the use of time growth, motion accuracy will be reduced, with the harmonic reducer light weight small size of the advantages of the opposite, RV reducer disadvantage is its heavy weight, large size.

Both are less tooth difference meshing, the difference is that a key gear in the harmonics is flexible, the need for repeated high-speed deformation, and therefore more vulnerable, so the bearing capacity and service life of the harmonic reducer compared with the RV reducer, the bearing capacity is low and the life is short. RV reducer is generally used cycloidal needle wheel, harmonic used before the involute tooth shape, and now some manufacturers use double circular arc tooth shape, which is more advanced than the involute.

Compared with the harmonic reducer, RV reducer is a new rise of transmission products, RV reducer is actually developed on the basis of the traditional needle and thread reducer, not only to overcome the shortcomings of the general needle pendulum transmission, but also has more advantages, such as long life, maintain stable accuracy, high efficiency, smooth transmission, small size, light weight, speed change ratio range.

For the question of whether the two can be replaced, there are actually two kinds of statements in general.

1. It can be replaced, but only some models can be replaced. The RV reducer we have mentioned earlier has much higher fatigue strength, rigidity and life than the harmonic drive commonly used in robots, and the precision of the return difference is stable, and the accuracy of the motion will be significantly reduced as the harmonic drive with the increase in the use of time. Therefore, many countries of high-precision robot transmission more RV reducer, so there is a development trend, RV reducer gradually began to replace the harmonic reducer in advanced robot transmission.

Harmonic reducer is characterized by light and small, in this respect, the planet and RV is difficult to do. Therefore, all kinds of reducers can only be replaced in a part of the case, but it is unrealistic to replace another product in a full range of products.

For the question of whether the two can be replaced, there are actually two kinds of statements in general.

These products do have an alternative relationship on some models, but these types of reducers can only be partially replaced. In most cases, various types of reducer are difficult to replace.

2, The second is that all kinds of reducer can not be replaced, only complementary.

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The two types of reducer, RV and harmonic, are complementary, but they do not exclude the formation of local competition in some application areas after structural design optimization and manufacturing process breakthroughs.

This is the comparison of RV reducer and harmonic reducer, between the two can not be said to be completely can replace each other, and the function of each reducer and the advantages are very different, enterprises should integrate the use of robot joints and the different performance of the reducer, choose the reducer products more suitable for the development of enterprises.

With the unmanned operation becoming more and more mature in recent years, industrial robots have become machines that are often used in many industries. Compared with general reducers, precision reducers, the core components of industrial robots, need to be unique and have the characteristics of short transmission chain, small volume, high power, light weight and easy control. The reducers with these two characteristics mainly include RV reducers and harmonic reducers. Many friends don't know the advantages and disadvantages between them. Today, Fu Bao will explain the differences between these two types of reducers.

1. Principles of RV and harmonic reducer.

RV reducer:

It is used for the three joints of the leg, waist and elbow of the robot with high torque, and the industrial robot with high load uses RV for the first, second and third axes. Compared with harmonic reducer, the key of RV reducer lies in processing technology and assembly technology.

RV reducer has higher fatigue strength, rigidity and service life, unlike harmonic drive, the motion accuracy will be significantly reduced with the increase of service time, and its disadvantages are heavy weight and large overall size.

Harmonic reducer:

Used for the end shafts of industrial robots or large robots with small load, the harmonic reducer is a kind of harmonic transmission device, which includes harmonic accelerator and harmonic reducer. Harmonic reducer mainly includes rigid wheel, flexible wheel, bearing and wave generator, and all of them are indispensable.

Among them, the number of teeth of the rigid wheel is slightly larger than that of the flexible wheel. Harmonic reducer used in small robots is characterized by small size, light weight, large bearing capacity, high motion accuracy and large single-stage transmission ratio.

Both of them are engaged with less tooth difference, but the difference is that a key gear in harmonic is flexible and needs repeated high-speed deformation, so it is fragile and has limited bearing capacity and life. RV usually uses cycloid pin wheel, and the harmonic wave used to use involute tooth profile. Now some manufacturers use double circular arc tooth profile, which is much more advanced than involute tooth profile.

Compared with the harmonic reducer, RV transmission is a new kind of transmission, which is developed on the basis of the traditional pin-pendulum planetary transmission. It not only overcomes the shortcomings of the general pin-pendulum transmission, but also has a series of advantages such as small size, light weight, large transmission ratio range, long service life, stable accuracy, high efficiency and smooth transmission.

RV reducer is composed of cycloidal pinwheel and planetary bracket, which is widely used in industrial robots, machine tools, medical testing equipment, satellite receiving systems and other fields because of its small size, strong impact resistance, large torque, high positioning accuracy, small vibration and large reduction ratio.
 

The shell of RV reducer and cycloidal pin wheel are driven by solid steel, so it has strong bearing capacity. However, the flexspline of harmonic reducer can constantly deform to transmit torque, which determines that the ability of harmonic reducer to bear large torque and impact load is limited, so it is generally used in the front end.

2. Advantages and disadvantages of RV and harmonic reducer.

The harmonic reducer has a simple and compact structure and is suitable for miniaturization, low and medium load applications.
RV reducer has good rigidity, strong impact resistance, stable transmission and high precision, and is suitable for medium and heavy loads.

However, RV reducer needs to transmit great torque and bear great overload impact to ensure the expected working life, so it uses a relatively complex over-positioning structure in design, and it is difficult to control the manufacturing process and cost. RV reducer has no elastically deformed stress element, so it can bear a certain torque.


The bearing of RV reducer is its weak link, and it is easy to break through the bearing limit of the shaft when stressed, resulting in abnormal wear or fracture of the bearing. This problem is more prominent when running at high speed, so the rated torque of RV reducer decreases obviously with the input speed.

In fact, all types of reducers have their own advantages and disadvantages. We can't simply say that a certain type is good and a certain type is not good. All these need to be selected according to the actual situation, which is what many friends don't understand. When choosing a reducer, we don't know how to choose a robot that is more suitable for our own. At this time, we can consult the technicians in Fu Bao to help our customers choose the type more accurately.

If you want to learn more, please visit our website rv reducer.