Spiral compression spring

Abstract

The utility model discloses a spiral compression spring which comprises supporting rings at the two ends and a spring body located between the two supporting rings, the spring body and the supporting rings are sequentially and spirally wound in a directional mode to form a cylindrical shape, and the two end rings of the spiral compression spring are tightly combined and ground to be flat or are tightly combined and ground to be flat after being flattened. A gap is formed between every two rings of the spring body, and a contact line compensation ring is additionally arranged on the supporting ring; the contact line compensation ring and the supporting ring are integrally formed, and the contact line compensation ring extends by a certain length from the contact point of the supporting ring and the spring body to the tail tip direction along the spiral line of the supporting ring. According to the utility model, the contact line of the cylindrical helical compression spring can be independently compensated, the length of the contact line meeting the standard requirement can be obtained without loading or loading a very small axial load, the properties such as the total number of turns, the number of effective turns, the free height, the compression height and the reserved safety stroke are not changed, the stability and the bearing capacity are improved, and the production cost is reduced. The service life is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to spring technical field, concretely relates to a spiral compression spring. BACKGROUND

[0002] According to the standard of "BS EN 13298:2003 Railway applications - Suspension components - Steel helical springs", the inspection and test of class A helical spring need to detect whether the contact line length meets the requirements; The contact line length is at least 0.33 of the average diameter D of the spring, and the measurement method of the contact line length is given. According to the standard of "TB / T2211-2018 Compression steel helical spring for rolling stock", during the type test, class A and class B helical springs need to detect whether the contact line length meets the requirements, and during the factory inspection, class A helical spring needs to detect whether the contact line length meets the requirements; The requirements of the contact line length are as follows: when the spring is under static load FV, the contact line length between the upper and lower end circles of the spring with parallel tight and ground flat end circle should be more than 0.33 times of the mean diameter D, and at least 20mm; For the spring with rolled tip, parallel tight and ground flat end circle, when the steel rod diameter d is greater than or equal to 20mm, the contact line length should be more than 20mm, and when the steel rod diameter d is less than 20mm, the contact line length should be greater than or equal to the steel rod diameter d. In summary, the importance of the contact line length in the spring, which has a great influence on the performance of the spring.

[0003] The contact line length refers to the length of the line that the end circle of the spring contacts with the connected part, which directly affects the carrying capacity, stability and service life of the spring. When the contact line length is short, the spring is prone to deformation under stress, which leads to a decrease in carrying capacity and increases the risk of fatigue failure. On the contrary, a longer contact line length can provide a larger contact area, thereby enhancing the carrying capacity of the spring, making it more stable under external force, and also dispersing stress and reducing stress concentration, thereby prolonging the service life of the spring.

[0004] In actual application process, most of the spring fractures are almost on the effective circle near the end. For example, the article "Analysis of Fatigue Failure Reasons of Cylindrical Helical Spring for Urban Rail Train" indicates that the fracture position of the locomotive primary spring in the use process is the first working circle on the inner spring upper surface, and the fracture surface forms an angle of 45° with the spring axis. The reason for the fracture is that the spring support circle end and the effective circle of the spring are continuously squeezed and collided during the operation of the locomotive, thereby causing fatigue fracture at the contact part due to stress concentration. This shows that the spring support circle and the effective circle are not in line contact but in local point contact during work. Therefore, the importance of the contact line length of the spring in the working process of the spring.

[0005] In order to ensure that the spring contact line length meets the standard requirements, there are some conventional solutions. For example, the angle between the spring support ring and the effective ring is reduced to prolong the spring contact line length, but the number of effective rings is reduced, resulting in excessive spring stiffness; the number of support rings is increased to prolong the spring contact line length, but the free height is increased, affecting the stiffness of the spring. The method adopted in the article "Analysis of Fatigue Failure Reasons of Cylinder Helical Spring for Urban Train" is to grind the spring to eliminate surface defects at the end of the support ring to prolong the spring contact line length, but it will consume time and effort; the end of the spring is rolled and forged by using a new type of rolling and forging die with arc grooves on the upper and lower rolling and forging surfaces of the rolling tip, so that the upper surface and the lower surface of the rolling tip are arc surfaces, to ensure the contact line length after the spring is wound, but the number of effective rings is reduced, affecting the stiffness.

[0006] The prior art CN 102537163 A "Design method of total number of spring" discloses a helical spring with a contact line compensation ring and a calculation method of the total number of rings. The extension direction of the contact line length in the article is opposite to that of the utility model. The total number of rings in the article = effective ring + length converted into the number of rings by grinding the end ring + length converted into the number of rings by the contact line. It can be seen that the number of rings converted from the contact line length causes the change of the total number of rings, thereby affecting the free height and the compression height of the spring. The contact line compensation ring of the utility model does not cause the change of the total number of rings, so compared with the same parameter spring without using the utility model, the stiffness, free height and compression height of the spring are not changed.

[0007] Therefore, it is necessary to provide a cylindrical helical compression spring which can ensure that the contact line length meets the standard requirements and the performance of the spring remains unchanged. Content of the utility model

[0008] The utility model aims at the deficiencies of the prior art, and provides a helical compression spring which can ensure that the contact line length meets the standard requirements and the performance of the spring remains unchanged.

[0009] The technical scheme adopted by the utility model is as follows:

[0010] A helical compression spring comprises support rings at both ends and a spring body between the two support rings. The spring body and the support rings are sequentially and directionally spirally wound to form a cylindrical shape. The end ring of the helical compression spring is in the form of tight grinding and flattening or tight flattening after being flattened. There is a gap between the rings of the spring body. A contact line compensation ring is additionally arranged on the support ring. The contact line compensation ring is integrally formed with the support ring. The contact line compensation ring extends from the contact point between the support ring and the spring body to the tail tip along the spiral line of the support ring.

[0011] Preferably, the contact line compensation ring does not change the number of total rings nt of the helical compression spring.

[0012] Preferably, the contact line compensation circle does not change the number of effective turns n of the helical compression spring.

[0013] Preferably, the contact line compensation circle does not change the free height and the compression height of the helical compression spring.

[0014] Preferably, both end circles of the helical compression spring are in the form of tight and ground flat or are flattened and then tightly and ground flat.

[0015] Preferably, the gaps between the turns of the spring body are equal.

[0016] Preferably, the length of the contact line compensation circle is the length of the arc corresponding to the rotation of the spring steel bar along the median diameter of the helical compression spring by 38°-90°.

[0017] Preferably, for the helical compression spring without requirement on the thickness of the end part, the arc corresponding to the rotation of the spring steel bar along the median diameter of the helical compression spring by 90° corresponds to the minimum median diameter of the helical compression spring, which is:

[0018]

[0019] Wherein D represents the minimum median diameter of the helical compression spring.

[0020] Preferably, for the helical compression spring with requirement on the thickness of the end part, the minimum bar size required for the contact line length (the length of the line contacting the connected part by the end circle of the helical compression spring) is:

[0021]

[0022] Wherein d represents the minimum bar size required for the contact line length.

[0023] The beneficial effects of the present utility model are:

[0024] (1) The present utility model has simple structure and ingenious design. A contact line compensation circle is extended from the contact point between the supporting circle and the spring body along the helical line of the supporting circle to the tail tip direction, which independently compensates the contact line length and changes the contact form between the supporting circle and the effective turns from local point contact to line contact. Without or with very small axial load, the contact line length meeting the standard requirement can be obtained.

[0025] (2) The total number of turns, the effective number of turns, the free height, the compression height and the reserved safety stroke of the cylindrical helical compression spring obtained by the present utility model remain unchanged, the stability and carrying capacity of the cylindrical helical compression spring are improved, the fatigue fracture caused by stress concentration is avoided, and the service life of the cylindrical helical compression spring is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 Front view of common helical compression spring;

[0027] Fig. 2 End view of common helical compression spring;

[0028] Fig. 3 Structure schematic view of the utility model;

[0029] Fig. 4 Front view of the utility model;

[0030] Fig. 5 End view of the utility model;

[0031] Fig. 6 Contact line length measurement result view of example 1;

[0032] Fig. 7 Contact line length measurement result view of comparative example 1;

[0033] In the drawing: 1-spring body; 2-contact line compensation ring; 3-support ring; 4-contact point. DETAILED DESCRIPTION

[0034] The utility model will be further explained in connection with the drawings:

[0035] As Figs. 1-2 shown, common helical compression spring includes spring body 1 and support ring 3, and spring body 1 and support ring 3 are sequentially oriented spiral winding, form cylindrical shape, and the end ring form of spring is parallel tight and grinds flat or is parallel tight and grinds flat after being flattened, and there is gap between the turns of spring body 1; the end of support ring 3 and spring body 1 is local point contact, and the contact point is the starting point of spring body 1; the end of spring grinds flat approximately at 3 / 4 turns.

[0036] As Figs. 3-5 shown, the utility model discloses a helical compression spring, which comprises support rings 3 at two ends and a spring body 1 located between the two support rings 3, the spring body 1 and the support rings 3 are sequentially oriented spiral winding to form a cylindrical shape, and the end ring forms of the helical compression spring are both parallel tight and grinds flat or is parallel tight and grinds flat after being flattened, there is gap between the turns of the spring body 1, and a contact line compensation ring 2 is additionally arranged on the support ring 3; wherein the contact line compensation ring 2 is integrally formed with the support ring 3, and the contact line compensation ring 2 extends a length in the direction of the tail tip along the spiral line of the support ring 3 from the contact point 4 between the support ring 3 and the spring body 1.

[0037] The contact line compensation ring 2 in the utility model does not change the number of total turns n t , the number of effective turns n, the free height and the compression height of the helical compression spring.

[0038] The helical compression spring of this invention has two end coils that are either tightly rolled and ground flat, or flattened and then tightly rolled and ground flat. The gaps between the coils in the spring body 1 are equal. The end coils of the helical compression spring of this invention are ground flat between 3 / 4 and 1 coil, and the length of the contact wire compensation coil 2 is less than or equal to 1 / 4 coil. The helical compression spring of this invention can achieve the contact wire length required by the standard without loading or with a very small axial load.

[0039] In this invention, the length of the contact wire compensation coil 2 is the length of the arc corresponding to the spring steel rod rotating 38° to 90° along the spring's mean diameter.

[0040] According to the standard BS EN 13298:2003 Railway Applications - Suspension Components - Steel Helical Springs, the contact wire length must be at least 0.33 times the average spring diameter D. Therefore, the minimum length of the contact wire compensation coil 2 can be obtained, which, when converted to the angle corresponding to the arc length, is:

[0041]

[0042] Therefore, after the mean diameter of the helical compression spring is determined, the length of the contact line compensation coil 2 is at least the length of the arc corresponding to the spring steel bar rotating 38 degrees along the mean diameter of the spring.

[0043] According to the standards BS EN 13298:2003 Railway Applications - Suspension Components - Steel Helical Springs and GB / T23934-2015 Technical Conditions for Hot-Rolled Cylindrical Helical Compression Springs, the end tip thickness should be between 3mm and 1 / 4 of the nominal cross-sectional dimension of the spring steel bar. The end face grinding length is approximately 3 / 4 of a turn, and the end face thickness after grinding 3 / 4 of a turn is approximately 1 / 4 of the bar size. Therefore, the minimum bar size that meets the contact line length requirement of this utility model can be obtained as follows:

[0044]

[0045] Therefore, d ≥ 20.8 mm.

[0046] Therefore, for rods with end thickness requirements, the minimum rod size that can meet the contact line length requirements of this utility model is 20.8mm, and the upper limit of the length of the contact line compensation ring 2 is determined according to the specific rod size; for rods without end thickness requirements, the rod size that can meet the contact line length requirements of this utility model does not need to be limited, and the length of the contact line compensation ring 2 is the length of the arc corresponding to the spring steel rod rotating 38° to 90° along the spring's median diameter.

[0047] According to the standard TB / T 2211-2018 Compression Steel Helical Springs for Locomotives and Rolling Stock, the contact wire length has different requirements for different end ring types.

[0048] 1) End circle is the form of parallel grinding flat, the length of the contact line of the upper and lower end circle should be more than 0.33 times of the diameter D, at least 20mm. Based on the above European standard, the requirement of contact line length of at least 20mm is added.

[0049] For the thickness of the end: from the above, the minimum bar size is 20.8mm, according to the standard of GB / T 23934-2015 hot coil cylindrical helical compression spring technical conditions, the winding ratio of spring ω is 3-12, take the winding ratio of spring as 3, get the minimum diameter of spring D=ωd=62.4mm, the corresponding contact line length L=0.33D=20.592mm>20mm, meet the standard requirements.

[0050] For the thickness of the end: from the above, the length of the contact line compensation ring 2 is the length of the arc corresponding to the spring steel bar along the spring diameter 38°-90°, wherein the arc corresponding to the spring steel bar along the spring diameter 90° corresponds to the minimum diameter of the spring:

[0051]

[0052] D≥25.5mm. The length of the contact line compensation ring 2 can meet the requirement of the length of the contact line.

[0053] 2) End circle is the form of parallel grinding flat after flattening, when the diameter of the steel bar d≥20mm, the length of the contact line should reach more than 20mm; when the diameter of the steel bar d<20mm, the length of the contact line should be greater than or equal to the diameter of the steel bar d.

[0054] (1) When the diameter of the steel bar d≥20mm, the length of the contact line should reach more than 20mm.

[0055] ① For the thickness of the end:

[0056]

[0057] Arranged:

[0058]

[0059] ω is represented by d:

[0060]

[0061] According to the standard of GB / T 23934-2015 hot coil cylindrical helical compression spring technical conditions, the winding ratio of spring ω is 3-12, the size of the bar d is 8mm-60mm. It can be obtained that 20mm≤d≤60mm

[0062] In summary, for the end thickness with requirements, the length of the contact line compensation ring 2 meets the requirements of the length of the contact line under the following conditions:

[0063]

[0064] 2. For the end thickness without requirements: taking the winding ratio as 3, the minimum pitch diameter D = 3d = 60 mm can be obtained, and the length of 1 / 4 ring L = πD / 4 ≈ 47.2 mm > 20 mm can be obtained. Thus, for the end thickness without requirements, the length of the contact line compensation ring 2 can meet the length requirements of the contact line.

[0065] (2) When the diameter of the steel rod d < 20 mm, the length of the contact line should be greater than or equal to the diameter of the steel rod d.

[0066] 1. For the end thickness with requirements:

[0067]

[0068] In summary:

[0069] (d-12)ωπ-4d≥0

[0070] Let d represent ω:

[0071]

[0072] According to the standard of GB / T 23934-2015 Hot Rolled Cylindrical Helical Compression Spring Technical Conditions, the winding ratio ω of the spring is 3-12, and the rod size d is 8-60 mm. It can be obtained that 13.5 mm ≤ d < 20 mm.

[0073] In summary, for the end thickness with requirements, the length of the contact line compensation ring 2 meets the requirements of the length of the contact line under the following conditions:

[0074]

[0075] 2. For the end thickness without requirements:

[0076]

[0077] It can be obtained that ω ≥ 4 / π

[0078] Since 4 / π < 3, for the end thickness without requirements, the length of the contact line compensation ring 2 can meet the length requirements of the contact line.

[0079] Example 1

[0080] The structure of the utility model is used for contact line compensation design of cylindrical spiral compression spring, the end ring is parallel and flat, and the manufactured spring is placed on the electro-hydraulic servo test bench for axial stiffness test.

[0081] Test conditions: GL-40T electro-hydraulic servo test bench, manual loading mode, spring end parallel and coaxial.

[0082] Test process: when not loaded, the contact line length is measured, then the load is gradually applied from 0kN to the axial load required for axial stiffness test, and the load is kept within ±1%, the contact line length and the spring axial stiffness are measured.

[0083] According to the test of example 1, when not loaded, the measured contact line length of the cylindrical spiral compression spring is longer, which meets the length requirement of the standard, and the contact line length measurement result is shown in the table. Fig. 6 The axial stiffness of the cylindrical spiral compression spring does not change during the test, which proves that the cylindrical spiral compression spring adopting the patent technology can ensure the contact line length to meet the standard requirements without affecting the performance.

[0084] Comparative example 1

[0085] The test conditions and test process are the same as example 1, only the cylindrical spiral compression spring without contact line compensation structure is used for axial stiffness and contact line length test.

[0086] According to the test of comparative example 1, when not loaded, the measured contact line length of the cylindrical spiral compression spring is 0, and the contact line length of the cylindrical spiral compression spring after stable load is measured as shown in the table. Fig. 7 The contact line length is shorter and still does not meet the standard requirements, and the effective number of turns of the cylindrical spiral compression spring is reduced, the axial stiffness of the spring presents nonlinear change during the test and gradually increases with the loading process, so it can be determined that the change of the contact line length causes the change of the effective turns, thereby causing the change of the axial stiffness.

[0087] From the test results of example 1 and comparative example 1, it can be seen that the cylindrical spiral compression spring adopting the patent structure can ensure the contact line length to meet the standard requirements during use, can solve the fatigue fracture problem caused by the contact line length not meeting the standard, and the stiffness and free height and other performances of the cylindrical spiral compression spring adopting the patent structure do not change.

[0088] Example 2

[0089] The structure of the utility model is used for contact line compensation design of cylindrical spiral compression spring, the end ring is parallel and flat, and the manufactured spring is placed on the electro-hydraulic servo test bench for axial stiffness test.

[0090] Test condition: GL-40T electro-hydraulic servo test bench, automatic loading mode, spring end kept parallel and coaxial, flat contact at both ends of spring.

[0091] Test process: cyclic loading was carried out on the spring until 2x10 6 times of infinite fatigue cycle or fracture, and the fatigue life of the spring was measured.

[0092] From the test of Example 2, the spring did not fail and fracture after 2x10 6 times of cycles under the design working condition.

[0093] Comparative Example 2

[0094] The test condition and test process were the same as those of Example 2, and only the fatigue life test was carried out on the cylindrical helical compression spring which was not designed with contact line compensation.

[0095] From the test of Comparative Example 2, the spring failed and fractured when the test was carried out to 5.10213x10 5 times of cycles, and the expected infinite fatigue cycle times were not reached.

[0096] From the test results of Example 2 and Comparative Example 2, it can be seen that the cylindrical helical compression spring adopting the structure of the present application can effectively prolong the fatigue life of the spring.

[0097] Example 3

[0098] The cylindrical helical compression spring was designed with contact line compensation according to the structure of the present application, the end ring was parallel and tight, and after the designed spring was subjected to the rated load by the finite element simulation calculation method, the stress distribution at the contact line position was checked by using the stress nephogram, and through comparison, the stress at the contact line position was relatively dispersed, and the stress difference with the surrounding position was not large.

[0099] Comparative Example 3

[0100] The same parameter cylindrical helical compression spring which was not designed with contact line compensation was subjected to the rated load by the finite element simulation calculation method, and the stress distribution at the contact line position was checked by using the stress nephogram, and through comparison, the stress at the contact line position was relatively concentrated, and the stress difference with the surrounding position was 1.5 times.

[0101] From the simulation calculation results of Example 3 and Comparative Example 3, it can be seen that the cylindrical helical compression spring adopting the structure of the present application can effectively relieve the stress concentration phenomenon at the contact line position, and can effectively avoid the fatigue fracture problem caused by stress concentration.

[0102] Other processes of the present application can adopt the prior art.

[0103] The best embodiment of the utility model has been illustrated, and further development of the utility model by those skilled in the art falls within the protection scope of the utility model.

Claims

1. A helical compression spring, characterized in that: The spring includes two support rings (3) at both ends and a spring body (1) located between the two support rings (3). The spring body (1) and the support rings (3) are spirally wound in sequence to form a cylindrical shape. The two end rings of the spiral compression spring are either tightly ground flat or flattened and then tightly ground flat. There are gaps between the rings of the spring body (1). A contact line compensation ring (2) is added to the support ring (3). The contact line compensation ring (2) and the support ring (3) are integrally formed. The contact line compensation ring (2) starts from the contact point (4) between the support ring (3) and the spring body (1) and extends a certain length along the spiral line of the support ring (3) towards the tail tip.

2. The helical compression spring according to claim 1, characterized in that: The contact wire compensation coil (2) does not change the total number of coils n of the helical compression spring. t The quantity.

3. The helical compression spring according to claim 1, characterized in that: The contact wire compensation coil (2) does not change the number of effective coils n of the helical compression spring.

4. The helical compression spring according to claim 1, characterized in that: The contact wire compensation coil (2) does not change the free height and compression height of the helical compression spring.

5. The helical compression spring according to claim 1, characterized in that: Both ends of the spiral compression spring are either tightly wound and ground flat, or flattened and then tightly wound and ground flat.

6. The helical compression spring according to claim 1, characterized in that: The gaps between the coils of the spring body (1) are equal.

7. The helical compression spring according to claim 1, characterized in that: The length of the contact wire compensation coil (2) is the length of the arc corresponding to the spring steel rod rotating 38° to 90° along the mean diameter of the spiral compression spring.

8. The helical compression spring according to claim 7, characterized in that: For helical compression springs where there are no requirements on end thickness, the arc corresponding to the spring steel rod rotating 90° around the mean diameter of the helical compression spring corresponds to the minimum mean diameter of the helical compression spring as follows: Where: D represents the minimum mean diameter of the helical compression spring.

9. The helical compression spring according to claim 7, characterized in that: For helical compression springs with end thickness requirements, the minimum bar stock size for the contact line length (the line length of the helical compression spring end ring in contact with the connected part) is: Where: d represents the minimum bar size required for the contact line length.

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