JB/T 3338.2-1993 Design and calculation of cylindrical helical compression springs for hydraulic components

This standard specifies the design and calculation of hydraulic cylindrical helical compression springs with round cross-section. This standard is applicable to the design and calculation of equal pitch hydraulic springs with a material diameter not greater than 10 mm, a winding ratio generally not less than 3, and an effective number of turns generally not less than 2. JB/T 3338.2-1993 Design and calculation of hydraulic cylindrical helical compression springs JB/T3338.2-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Hydraulic cylindrical helical compression springs
Design and calculation
1 Subject content and scope of application
JB/T3338.2.-- 93
Generation 1B3338~83
This standard specifies the design and calculation of round-section cylindrical helical compression springs for hydraulic parts (referred to as hydraulic springs). This standard is applicable to the design and calculation of equal-pitch hydraulic springs with a material diameter not exceeding 10mm, a winding ratio generally not less than 3, and an effective number of turns generally not less than 2 turns.
2 Reference standards
GB 2271
GB3123
GB 4357
GB4358
GB4361
GB 5218
Valve Oil quenching-tempered chrome vanadium alloy spring steel wire Silicon bronze wire
Carbon spring steel wire
Piano wire
Oil quenching-tempered silicon manganese alloy spring steel wire
Silicon manganese spring steel wire
GR 5219
Chrome steel spring steel wire
JB/T 3338.1
Technical conditions for cylindrical helical compression springs for hydraulic parts YB(T)1I Stainless steel wire for springs
3 Parameters, codes and units of springs
The parameters, codes and units of springs are shown in Table 1 of JB/T3338.1. Table
Material name
Carbon spring steel wire
(GB4357)
Piano wire
(GB4358)
Oil-hardened and tempered chrome-vanadium alloy spring steel wire for valves (GB2271)
Chrome-vanadium spring steel wire
(GB 5219)
Silicon manganese spring steel wire
(GB5219)
Shanze fire-inter-fire silicon manganese alloy spring steel wire
（GB4361)
Group, category
【Shear modulus G allowable shear stress
The Ministry of Machinery Industry of the People's Republic of China approved 690 on 1993-05-07
Select according to Figure 1
See material standard
Recommended use Occasions
Class A springs use C, J, 2
Group; Class B and Rui springs use C, D) and G1 groups
Select only when there are special requirements
1994-01-01 implementation
Material name
Stainless steel wire for springs
[YR(T)11]
Silicon bronze wire
（GB3123）
Note: The lower limit is taken.
Typical working conditions of hydraulic springs
JB/T3338.2—93
Continued Table 1
Group, category
Shear modulus G|Allowable shear stress []
Typical working conditions of hydraulic springs are shown in JB/T3338.1 Table 2. Table 2
Parameter name
Curvature coefficient
Spring middle diameter
Spring outer diameter
Spring inner diameter
Total number of turns
Spring stiffness
Compression load
Compression deformation
Compression height
Free height
Working height
Working load
Compression shear stress
Working shear stress
See material standard
[r]=0. 450m
See material standard
Calculation formula
4C-10.615
D,--n+d
Recommended use occasions
When corrosion resistance is required or working under high and low temperature conditions, choose
When high corrosion resistance is required or working under anti-magnetic conditions, choose
Here n is rounded. It is recommended to take the tail number as 0.25.0.5.0.75 circles or full circles
Fr= Pb/P
Hb=(n-0. 5)d
H(Hi.5-P2) -- H.-
P,(P1s,P2)
P(P.-P.)-[H.-H,(Hi.、H2)JP
Type A spring
Type B and C springs
Ti(ti.5vt2
BKCP,(Pa.s、P.)
There are some differences with the design requirements
Theoretical value
Should be properly rounded. Ph will change
H when P is known
P when H is known
Parameter name
Maximum compression height
Height-to-diameter ratio
Opening length||tt ||Spring weight
Spring natural frequency
Outer diameter increase
5Design basis
Spring working condition (type, group);
Load nature;
Maximum working load P2;
Stiffness P;
Allowed installation space;
Working environment;
Life requirements;
6Design calculation formula
The calculation formula for material shear stress:
Where the curvature coefficient K is calculated by the following formula:
JB/T3338.2--93
Continued Table 2
Calculation formula
H eunax == ndmax
y=3.56×10°%
l(td)(t 0. 2d)
K= 4C-1+ 0. 615
4C—4
When H must be evaluated, use the ratio
α--helix angle
p--material density
（1）
.·(2)
When using formula (1) to calculate the compressive shear stress th, test shear stress t, and working shear stress of Class A springs, the curvature coefficient K value is equal to 1. When calculating the working shear stress of Class B and Class C springs, the curvature coefficient K is calculated according to formula (2). 6.2 Calculation formula for spring deformation F:
6.3 Calculation formula for spring stiffness P':
6.4 Calculation formula for single-turn spring stiffness Pa
P'u=nPr
（5）
7 Basic procedure for spring design
JB/T 3338.293
7.1 Determine the class and group to which the spring belongs
Based on the application of the spring and the typical working condition analysis of the hydraulic spring, determine the class and group to which the spring belongs. 7.2 Determine the load properties of the spring, the maximum working load 1 and the stiffness P°. 7.2.1 Determination of the load properties of the spring
a. Class A springs belong to Class H;
b. Class B and Class C springs belong to Class 1 or Class II. 7.2.2 Stiffness P of Class A springs
For Class A springs, the maximum working load P and the deformation F2 are known, and its stiffness P\ can be calculated according to formula (4). 7.2.3 Stiffness P of Class B springs
For Class B springs, the two-point load PIP and the deformation AF are known, and the stiffness can be calculated as follows: P2-P
7.2.4 Stiffness and maximum working load P2 of Class C springs. For Class C springs, the deformation △F under the load difference △P is known, and the stiffness Pi can be calculated as follows. a
The maximum working load P is calculated by the following formula: AP
P2=(3. 5~4)AP
7.3 Selection of materials, allowable shear stress and shear modulus Materials, allowable shear stress [t and shear modulus pad G are selected according to Table 1. 7.4 Selection of compression shear stress
...... (8)
a. When T,=［t], the design is most reasonable, and the spring will not produce permanent deformation when compressed to any height: b. When (1～1.25)[], the designed spring should have no permanent deformation after strong pressure treatment, and its structural dimensions should be small; c. When z≥1.25LtJ, the test height H and test load P should be specified on the drawing. The load is determined by the test shear stress. z(11.25)[ should be taken. As long as the compression height is greater than the test height, the spring will not produce permanent deformation. 7.5 Selection of maximum 1 shear stress 2
a. Class A springs work under high stress and high temperature for a long time, and their working temperature can reach 80℃. Take T2≤(.6; b. Class B and C springs require a working life of more than 10° times, and take the maximum working shear stress z2-(0.6～~0.7)zb. 7.6 Compression height H and maximum compression height Hbaux For springs with both ends tightened and ground flat, the theoretical compression height H is calculated as follows: Hh=(n --0.5)d
（9）
The actual value of the pressed height H is related to the material diameter d, the total number of turns n deviation and the grinding amount of the end, which is generally greater than the theoretical value. Therefore, it is stipulated that the value of the spring with a certain pressed height should be indicated on the drawing as not greater than Hbmx. Its value is calculated by the following formula: Hbmax nidmax ..*...
7.7 Spring diameter annotation method and determination of assembly clearance Hydraulic springs should be accurately positioned in hydraulic parts. (10)
Springs installed in holes should be marked with outer diameters, otherwise marked with inner diameters. The minimum clearance between the spring seat column and the inner diameter of the spring is not less than 0.2mn. The clearance between the spring seat hole and the outer diameter of the spring depends on the increase in the outer diameter △D2 when the spring is pressed. The minimum clearance is △D:. △D, is calculated as follows:
(td)(t-0. 2d)..
（11）
7.8 Design calculation of basic parameters
7.8.1 Calculation of main design parameters d, D and n7.8.1.1 Direct design calculation using formula
JB/T3338.2—93
Use shear stress and deformation calculation formulas (1) and (3) to calculate parameters, but it is impossible to obtain definite solutions for the three unknowns (d, L) and n) using two equations. Other constraints should be met to finally determine them. Usually, these three main parameters are determined according to the installation space conditions. Therefore, it is usually necessary to perform repeated trial calculations.
7.8.1.2 Design calculation using P curve
a: Given the maximum working load P of the spring and the stiffness 7\, determine the selected material and its allowable shear stress [t according to Table 1 or Appendix A1. However, the allowable shear stress of carbon spring steel wire, piano steel wire and oil-quenched valve spring steel wire is related to the material diameter α, so a material diameter α should be initially selected to determine the allowable shear stress, and the allowable shear stress gate b should be corrected after the final diameter d is determined. Determine the maximum working shear stress t2 according to Article 7.5. Calculate the Pk value according to the following formula:
. (12)
The equivalent curve of the P value can be found on the P curve diagram in Appendix A (Supplement) or by insertion. On this curve, there are many combinations of material diameter d, winding ratio C, and single-turn stiffness P'. The spring center diameter D can be obtained from the winding ratio C, and the effective number of turns n can be obtained from the single-turn stiffness P\. The combination of material diameter d and winding ratio (changes from small to large, and the law of spring shape change is from slender to short and thick. Then, according to the spring installation space conditions, a group of appropriate parameters can be selected to reduce repeated calculations. 7.8.2 Determine the free height of the spring 1.
Calculate the compression load Pb according to the following formula:
Calculate the total deformation Fb according to the following formula:
Calculate the compression height H according to the following formula (the support circle n is counted as 2 circles): H -- (n+1. 5)d
If the height is too large, it can be taken:
t (1 ~1. 25)[]
tz=(0. 6～0. 7)=(0.6～0.7)(1～1.25)[t)Recalculate the three main parameters of the spring according to Article 7.8.1, H, can be reduced. 7.8.3 Confirmation calculation
After determining the main parameters and free height, the final confirmation calculation is carried out. It can be carried out according to Table 2 as needed. 7.9 Fatigue strength and stability check of spring When it is necessary to check the fatigue strength, stability and resonance of the spring, it shall be carried out in accordance with GB/T1239.6. 7.10 Standing treatment
(13)
(14)
(15)
(16)
Standing treatment is a process method in which the spring after heat treatment is subjected to several short compressions in order to achieve the stability of the free height. Generally, when the shear stress is (0.8~1) times the allowable shear stress [], the manufacturer shall adopt standing treatment, and it is not necessary to mark this requirement on the working drawing.
7.11 Selection of strong pressure treatment
Strong pressure treatment is a process method that compresses the spring to a state where the surface stress of the material exceeds the elastic limit and maintains it for a certain period of time to achieve strengthening or 694
JB/T3338.2-93
stabilization of size. It is also possible to use dozens of short compressions instead of long-term pressure holding. Therefore, the spring subjected to strong pressure treatment must be compliant and the shear stress is greater than the allowable shear stress].
7.12 Selection of shot peening
Shot peening can appropriately increase the fatigue life of springs bearing class 1 and 1 loads. When the material diameter d is less than 1.8mm or the spacing) is less than 1.2mm, springs are generally not shot peened. Springs with silicon bronze wire are not shot peened. 7.13 Spring end structure
The spring end structure adopts the two end faces that are tightened and ground flat. The surface roughness requirement is that the number of support circles n shall not be less than 2 circles. The end face chamfer can be determined according to the product positioning needs and indicated on the drawing. 7.14 Draw the working drawing of the spring
The drawing format refers to Appendix A (supplement) of JB/T3338.1. Appendix
Pe curve
(supplement)
Ps curve is drawn according to formula (1) when P equals P when the shear stress is 1000N/mm2 and formula (5). The horizontal axis of this figure is the material diameter d, and the vertical axis is the winding ratio (, the thick solid line curve in the figure is the P curve family with different P values, and the thick dotted line curve is the P\ curve family with different single-turn stiffness P\a values. Any point on the coordinate plane corresponds to four parameters, namely material diameter d, winding ratio C, P and single-turn degree Pi, which represent the geometric dimensions and performance of a single-turn spring. As long as two of the parameters are known, the other two parameters can be determined. Any spring with an effective number of n turns can be understood as a series connection of n identical single-turn springs. In a certain equal P For a spring composed of a material diameter d and a winding ratio C corresponding to any point on the k value curve, when the load P is this P, the shear stress of the spring is exactly 1000N/mm2, and the corresponding single-turn stiffness P\ on the equal P curve is not equal, and becomes smaller as the winding ratio C value increases. When the stiffness P' of the spring is required to be constant, the effective number of turns n of the spring will also change from more to less.
Using this diagram can help simplify spring design, and can also quickly verify the shear stress and stiffness of existing springs. 695
JB/T 3338.2—93
B1 Pressure regulating spring
JB/T3338.2--93
Appendix B
Example of design calculation of hydraulic spring
(reference part)
Design the pilot valve pressure regulating spring of three pressure levels of the overflow valve. The working load is shown in Figure B1. The pilot valve core is conical. The column diameter D of the spring installed on the spring seat is 5.6mm. The installation space height H is 34mm. The footnotes A, B, and C represent the three levels of pressure regulating springs respectively. Pee=453N
Pa=250N
PA=129N
P*=21.5N/mm
Pg=45 .5N/mm
P:=141.6N/mm
From the typical working condition classification of JB/T3338.1, it can be known that the spring belongs to Class A Group I, and the load property belongs to Class I. The inner diameter D of the spring is 6±0.2mm, and the free height H. should be 33.5±0.5mm. B1.1 Material selection and its allowable shear stress [
According to the load property, GB4357 carbon spring steel wire grade D is selected. The allowable shear stress Lr of this material] is related to the material diameter. According to the known load conditions, the material diameter is estimated to be approximately between 2 and 3mm. The allowable shear stress [+] is temporarily taken as 850N/mm. B1.2 Selection of working shear stress 2 and determination of Pk value Take t2=0.6[-] 510N/mm2
Then PhA
X1000-253N
P2×1000=490N
X1 000-888N
B1.3 Selection and preliminary calculation of main parameters of spring The inner diameter D of the spring is 6±0.2mm, then: C
A curve of equal inner diameter conditions can be drawn on the Pk curve, and there is an intersection with the equal value curves of Pka, Pku, and Pkc values. This intersection cannot be exactly on the material series diameter. The diameter value of the nearest material series can be taken along the equal inner diameter curve to the right. Get the data listed in Table B1 and make preliminary calculations.
D=D,td
P\g=Gd/8c3
Rounded
pt=P'a/n
H, -(ni—0. 5)d
Pr-gCKT
Fb= Pr/p
(H,)=H,+Fb
Design value
JB/T 3338.2-93
Check the curve to determine
Check the P curve or calculate according to the formula
Take G-78400N/mm2
Calculated value
Confirmed value
Design joint value
Take = 2
Check Figure 1 to get
Take the calculated value when t［]K—i
Calculated value
Spring C increases the pitch,
Take AHH. -(H). =4. 9
Take H,=H+AH27. 3
Preliminary calculation results show that the free height of spring C should be increased, so the test height H. value should be specified, and it should be noted on the working drawing that "pressure over 27.3mm is not allowed".
B1.4 Final confirmation calculation and drawing
Confirm the calculation according to Table 2, fill in the results in the working drawing table, and draw the drawings shown in Figures B2, B3 and B4. Since the C-grade spring has an increased pitch, the H. and P. values ​​must be marked on the drawings. 698
(H=245N)
JB/T3338.2:-93
B=129±12.9N
H,-33,5 ±0. 5
Technical requirements
1. Direction of rotation: right-handed,
2. Effective number of turns: n=10.5 turns.
3. Total number of turns: n1=12.5 turns.
4. Both ends are tightened and ground, the grinding surface is not less than 270°5. The inner and outer chamfers of the two end surfaces are 0.3×45°, and the burrs are removed. 6. Verticality tolerance: 0.6mm.
7. Surface anti-corrosion treatment.
8. The rest is in accordance with JB/T3338.193.
Class A Group 1 Spring Condition Design Calculation Data
Title Bar
Hb :--24 -2
Pb =407. 3)
IB/T 3338.2-..93
P,=250±25.0N
Technical Requirements
1. Direction of rotation: yes,
2. Effective reading -9.5 circles.
3. Total: m11.5 Figure.
4.Both ends are sealed, tightened and ground, with the grinding angle not less than 270°. 5.Inside and outside chamfers of both ends are 0.3×45 to remove burrs. 6.Vertical tolerance: 0.4mm.
7.Surface anti-corrosion treatment
8.Others are in accordance with the provisions of J13/T3338.193.
Class A Group 1 Spring Working Condition Design Calculation Data
Title Bar
(Pb =151ON）
(P,=848.4N)
JB/T3338.2-93
Complex V
Class A Group 1 Spring Working Condition Design Calculation Data
P=453 ±45.3N
H, = 27 .5
Ho-33.5±0.
Technical Requirements
1. Direction of rotation: right hand.
2. Effective number of turns n6.5 turns.
3. Total number of turns called =8.5 turns.
4. Tighten and grind the two ends, with the grinding surface not less than 270°. 5. The inner and outer chamfers of both ends are 0.3×45°, and the burrs are removed. 6. Verticality tolerance: 0.3mm.
7. Surface anti-corrosion treatment
8. The spring shall not be compressed more than 27.3mm. bZxz.net
9. The rest shall comply with the provisions of JB/T3338.193.
784009
Title bar
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