Principle characteristics and technical application of disc spring washer industrial solutions

The butterfly spring washer, the dish spring, is more than 3000 at the design point, and the overstress product is defined as the washer category, not the spring. Because of its shape, a dish spring is like a bottomless metal plate, a dish referred to as a dish spring, also known as a bell washer. It consists of four parameters: outer diameter (D), inner diameter (d), thickness (t), height (Ho), can withstand axial load, commonly used metal steel strip, steel plate or forging billet production, and processing of elastic components.

The dish spring was invented by the French J. Belleville in 1866 when it was mainly used as a washer. It was patented in the United States and France, also known as Belleville Spring. The research on disc spring was primarily in the 1970s.

 The principle of the butterfly spring washer

The butterfly spring washer is a conical ring disc with an axial load. Under normal circumstances, the disc's thickness is constant, and the load is evenly distributed on the inner edge of the upper surface and the outer edge of the lower surface. Butterfly spring washers are usually made of spring steel and can withstand static, impact, or dynamic alternating loads to meet strict fatigue life and load loss requirements. When the disc spring is flattened, a continuous elastic force is generated, which keeps a friction force in the threaded connection between the nut and the bolt, creating a resistance moment and preventing the nut from loosening.

The characteristics of the butterfly spring washer

The dish-spring washer has the characteristics of small volume, large load, convenient combination, and so on, and has the advantages of concentrated load transfer. The dish-spring washer can obtain various curves using single-piece combinations, multi-piece superimposed combinations, and mixed combinations. The cylindrical coil spring is used extensively in the mechanical industry, reflecting the new product (host) design of miniaturization and multi-functional characteristics. For example, in the direction of load, the more minor deformation can bear the more enormous load, and the axial space is compact. Compared with other types of springs, its deformation energy per unit volume is more significant and has better cushioning and absorbing capacity. Especially with the superimposed combination, absorbing shock and dissipating energy is more critical due to the damping surface friction. At present, dishspring washers are widely used in national defense, metallurgy, engineering, electric power, machine tools, construction, and other industries, such as mold, support hanger, clutch, brake, bridge buffer (shock absorption) devices, bearing preload, safety overload device, heavy machinery, mechanical starter, control device, valve, industrial furnace, indexing device, clamping device, and so on.

1. The size is small in the direction of load action and can bear a large load when the deformation is small, the axial space is compact, and the deformation energy is significant.

2. according to different h0/t, approximate straight line, gradually decreasing type, gradually increasing type, zero stiffness, and even negative stiffness characteristics can be obtained with variable stiffness characteristics.

3. Free combination, convenient, and can be standardized in production, use, maintenance, and management, which is convenient.

Select the primary type of dish spring washer

Dish-spring washers are divided into two types: unsupported surface and supported surface. Due to the rounded edges of the disc-spring washers with supporting surfaces, the tension loss caused by the friction caused by the spring back during the operation of the disc-spring washers is significantly reduced. It can be used individually, or it can be used in combination, superimposed combination, or composite combination to form a dish spring washer group. Withstand static load or variable load. It suits heavy machinery or molds with small installation space and large loads. At present, engineers in advanced countries such as Europe, the United States, and Japan have applied dish-spring washers extensively in mechanical components. In addition to safety performance considerations, it also replaces the shortcomings of the original traditional helical spring, such as limited space and load and excessive compression stroke, and improves mechanical performance. With a support surface, the compression space of the single disc spring washer is larger, the spring-mass is lighter, and the material is saved based on realizing the same load with the disc spring washer without a support surface at 75% of the same displacement. Due to the support surface, the force point is moved in, resulting in the shortening of the lever arm. In the case of the same torque, the load will increase, compensating for the load loss due to the thickness and achieving the same phenomenon. In addition to being lightweight and increasing compression, disc-spring washers with support surfaces are more accessible to stack and less prone to misalignment when combined. The size of the support surface is generally 1/150 of the outer diameter.

The technical requirements of the disc spring washer

1. It is recommended to use 60Si2MnA or 50CrVA material, and you can also choose stainless steel, heat-resistant steel or other copper alloys, titanium alloys, nickel-based and cobalt-based alloys.

2. The limit deviation of size and shape position: The standard divides the size and load accuracy of the dish spring washer into one and two levels of accuracy. Dimensions include diameter (inside and outside diameter), thickness, and free height.

3. Shape and position limit deviation: no standard, but Germany DIN2093 has requirements, such as concentricity, D≤50 for 2.1T11; When D > 50, it is 2.1T12.

4. Surface, heat, and pressure treatments have precise requirements. The surface, whether oxidized or phosphating, is not allowed to have burrs, cracks, and scars that are harmful to use. For quenching and tempering treatment, the number of quenching shall not exceed two times, the hardness shall be in the middle of 42HRC~52HRC, and the depth of the unilateral decarburization layer shall not exceed 5% of the thickness of the 1 class dish spring washer. The two and 3-class dish spring washer shall not exceed 3% of the thickness (maximum not exceeding 0.15mm).

5. Pressure treatment is a necessary process. The treatment method uses the load compression spring of 9:2FF =0.75h0, a duration of 9:12h, short-time compression, and a number of compressions of 9:5 times.

6. Special surface anti-corrosion treatment and unique technical requirements for strengthening treatment (such as fatigue, relaxation, creep, etc.) shall be stipulated by agreement between the two parties.

Dish spring washers are commonly used materials

1. Spring steel: 65Mn, T7A, T8A, T9A, T10A, 60Si2MnA, 50CrVA, 70Si2CVA, 30W4Cr2VA;

2. Stainless steel: Martensitic stainless steel: 3Cr13; Austenitic stainless steel: 301, 302, 316; Domestic brand: 12Cr17Ni7, 12Cr18Ni9, 06Cr19Ni10, 0Cr17Ni12Mo2; Precipitation hardening stainless steel: 630, 631, 632; Domestic brand: 05Cr17Ni4Cu4Nb, 07Cr17Ni7Al, 07Cr15Ni17Mo2Al;

3. High elastic alloy: 3J21;

4. Alloy for elastic components: 3J1, 3J53;

5. Copper alloy: silicon bronze, tin bronze, aluminum bronze, beryllium bronze, aluminum white copper, white copper;

6. High temperature resistant elastic alloy: GH4169, Inconel 718 namely NiCr19Fe18Nb5Mo3TiB; GH4145, Inconel ×750, namely NiCr15Fe7NbTi2Al; GH4090, Nimonic90;

7. Cobalt base alloy: HS25(L-605);

8. Niobium base alloy: 55NbTiAl;

9. Metal, ceramic, memory alloy, polyurethane, rubber, plastic, glass fiber, and carbon fiber can be manufactured as disc springs.

The type of dish spring washer

It is generally divided into ordinary dish springs, dish springs with radial grooves, and trapezoidal section dish springs.

Dish spring (dish spring washer), according to its use, can be divided into anti-loose dish spring, high-temperature resistance dish spring, low-temperature resistance dish spring, anti-corrosion dish spring, high torque dish spring, high torque dish spring, bearing preload dish spring washer, valve dish spring washer and so on.

Dish spring selection elements:

1. Size: The specific size elements of each product are specified in domestic and international standards. The main dimensions are outer diameter D, inner diameter d, thickness t, free height H, etc.

2. Temperature: According to its working and material characteristics, the disc spring washer is divided into four temperature ranges: average temperature, 150℃, 300℃, and 600℃.

3. State: the working state of the customer's equipment, such as preload stroke, vibration, pulse pressure frequency, spectrum, preload force, and other factors.

Medium: The working environment often has precise requirements for choosing dish spring washers; the main factors are the medium's corrosion, PH value, etc.

4. Pressure: several points of load and high-frequency fatigue

Characteristic curve and installation method of disc spring washer

Minimize the number of reeds used when stacking. The more disc spring washers are superimposed, the greater the friction loss of elasticity and the greater the deformation of the reed plane. It is recommended that the superimposed length L0≤3De and the reed should be coated with lubricants (grease, molybdenum disulfide, etc.).

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