Hardening of helical coil springs

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and may be used for helical spring hardening. This process comprises spring winding, heat treatment, sand blasting, spring hardening by aging in compressed condition or its 3-5-fold contraction till contact between turns and cold-hardening. Spring winding is executed with pitch larger than that of finished spring, luminescence control is performed and heat-treated spring ends are finished. Cold-hardening is executed at final stage by stamping of the spring inner and outer surface by pushing contracted spring tightly fitted on male die through female die hole with diameter smaller than that of spring on male die.

EFFECT: stable resilience, higher efficiency of hardening.

2 cl, 1 dwg

 

The technical field to which the invention relates

The invention relates to mechanical engineering, in particular to a method for hardening cylindrical helical compression springs.

The level of technology

The known method of hardening of springs, wheel blasting, which is the most common in the manufacture of springs. The essence of the process of blast cleaning is that the part after the final mechanical or thermal treatment is subjected to impact flow of steel or cast-iron shot. Shot-blasting coil springs to produce mechanical or pneumatic shot-blasting machines, steel or cast iron roll with a diameter from 0.4 to 1.8 mm (Ostroumov, V. P. Production of cylindrical helical springs / V. P. Ostroumov. - M.: Mashinostroenie, 1970. - with 135, p. 74...75).

When shot blasting treatment on the surface of coils are two-way residual compressive stress, preventing the disclosure of fatigue cracks and increases the endurance limit of 40-80%. (Lavrinenko, J. A. Hardening springs / Y. A. Lavrinenko, G. E. Proteins, V. V. Fadeev - Ufa: Publishing house "Business Partner", 2002. - 124 p. 16).

The disadvantage of this method is that the shot-blasting treatment does not eliminate the unevenness of the stress distribution over the cross section of the coil spring. The coils of the coil springs usually have a significant to�Visnu. This leads to a significant increase in stress up to 40% domestic 1 fiber turns, compared to the stresses in the outer fiber of turns. (Ponomarev, S. D. calculation of the elastic elements of machines and devices / S. D. Ponomarev, L. E. Andreeva. - M.: Mashinostroenie, 1980. - 326, p. 88). In operation, the spring on the inner side of the section of the turns develop fatigue cracks.

It is known that the highest stability of elastic properties depending on the type of treatment the spring show after treatment cracking (Ostroumov, V. P. Production of cylindrical helical springs / V. P. Ostroumov. - M.: Mashinostroenie, 1970. - with 135, p. 93...96). By analogy with this wheel blasting of springs must be compressed until contact coils (tense) state. When wheelblast compressed spring flow fraction reaches only the outer side of the coils, and the inner side of the turns will remain soft, which is a disadvantage.

A method of peening a cylindrical helical spring comprising a winding, hardening, tempering, shot blasting and zanemarivanje, and at the final stage produces a hardening of the inner surface of the springs. Hardening is carried out using the pulling mandrel or impact force to the inner surface of the coil spring. Pre�the proposed device for implementing the method - the mandrel or hardening the head with rollers mounted on the lathe, in the mounting bracket which is fixed a spring (Patent RU 2462519, IPC C21D 9/02, C21D 7/06, B21F 35/00. The method of hardening of cylindrical helical springs / O. I. Shavrin, 2011115786/02; stated 20.04.2011; published on 27.09.2012. Bul. No. 27).

The disadvantage of this method, taken as a prototype, is the complexity of the fastening of the spring to the mounting bracket lathe and the possibility of damage to her turns with uneven distribution of clamping forces and forces from the pulling mandrel or against impact rollers head of an unnamed model (brand).

The disadvantages are the duration of the process: install the spring into the device and delete from, bringing into rotation of the spring and the working tool (mandrel or head with rollers), for supplying and discharging the working tool. Not resolved the issue of the withdrawal of the spring with the working tool, which is also a disadvantage.

In this way, the term "zanemarivanje" are 3 - or 5-fold compression of the spring until the contact between the turns, that really is not Saavalainen, and considered a preliminary draft that is used to detect gross deviations from the process. Basic sediment of the springs, including cyclic, is produced by the operation of samevolume, cotherapist for the first 20-30 hours, and then increases slightly. (Ostroumov, V. P. Production of cylindrical helical springs / V. P. Ostroumov. - M.: Mashinostroenie, 1970. - with 135, p. 65...68).

It is known that the highest stability of elastic properties depending on the type of treatment the spring show after treatment cracking (Ostroumov, V. P. Production of cylindrical helical springs / V. P. Ostroumov. - M.: Mashinostroenie, 1970. - with 135, p. 93...96). Similarly the hardening of the inner surface of the spring in the present invention must be in a compressed state that is not executed. It is also a disadvantage adopted for the prototype method.

Disclosure of the invention

The object of the invention is to increase the stability of the elastic properties of the spring and reducing installation time and removing springs from the device and time of hardening of the springs in a compressed state. The technical result, the aim of the invention is to provide plastic deformation simultaneously on the outer and inner surfaces of the compressed spring coils and to increase the productivity of hardening.

The technical result is achieved in that a method of peening a cylindrical spiral spring includes coiling from pre-hardened or hardened wire with a pitch greater than the pitch PR ready�of the spring by the amount of the allowance under zanemarivanje and stamping (6-14% of the height of the finished spring), heat - treatment-leave for springs from a pre-hardened wire or quenching and tempering for springs of hardened wire, luminotron, grinding end faces, shot-blasting, zanemarivanje. At the final stage produces a hardening of the stamping of the outer and inner surfaces of the spring by pushing the tightly clad on the plunger spring compression through the die opening device, the diameter of which being smaller than the diameter of the punch spring 0.2-2 mm depending on the diameter of the coil. Thus a hardening of the outer and inner surfaces of the spring occurs due to the deformation of the turns of 0.2-2 mm between the punch and the matrix. The work hardening 1-2 seconds.

Brief description of the drawings

Fig. shows an apparatus for hardening cylindrical helical springs.

The implementation of the invention

The method of hardening a cylindrical spiral springs is as follows. For example, the spring springs are coiled with a pitch greater than the pitch ready for the spring by the amount of the allowance under zanemarivanje and stamping (6-14% of the height of the finished spring), thermoablative, exercise luminotron, sanded the ends, produce shot-blasting, canevaluate or produce a 3-5-fold compression, before touching turns. At the final stage produces a hardening of the stamping of the outer and inner surface�ness of the spring by pushing the tightly clad on the plunger spring compression through the die opening device, the diameter of which being smaller than the diameter of the punch spring 0.2-2 mm depending on the diameter of the coil. The work hardening 1-2 seconds.

For work hardening stamping inner and outer surfaces of the spring 1 is proposed to use a device comprising a matrix 2, the punch 3 with a flange 4, focus 5. The matrix 2 should be fixed on the table a stamping press (Fig. not shown), and the punch 3 - to the top plate of a stamping press. The spring 1 is mounted with clearance in the upper bore of the matrix 2, where it rests on the conical boring or emphasis 5. Then the movement of the press is lowered, the punch 3 down. The plug 3 fits into the spring 1 until it stops in the flange 4 of the punch and goes, continuing the downward movement and against the spring into the second bore, the diameter of which is less than the outer diameter of the compressed and located on the punch 3 of the spring 1. Coming out of the matrix 2, the spring 1 will slightly increase its diameter, after which the return movement of the upper press plate remove the spring 1 with the punch 3, as the spring 1 will rest against the end face of the matrix 2 and it will not go.

The spring 1 is subjected to heat treatment (quenching and tempering for springs of hardened wire and leave for springs from a pre-hardened wire), shot-blasting, zanemarivanje or 3-5-fold compression before contact of the turns, is subjected to further processing inner�and outer surfaces of the turns. Hardening the inner and outer surfaces of coils is due to the fact that the difference of diameters of the inner surface of the die 2 and the punch 3 is less than the diameter of the coil spring 1 0.2-2 mm. On the inner and outer surfaces of the coil springs 1 are formed of hard metal zone and thus increasing the yield strength, created internal compressive stresses, which increases fatigue strength and durability of the spring 1.

Presents the operation of hardening the inner and outer surfaces of the springs 1 punching more efficient than the known method of hardening the inner surface turning processing, as occurs at high speed stamping press and can be mechanized using applied when punching devices for installation in the stamp and remove details from the stamp. The installation of the spring 1 in the matrix 2, push the spring through the matrix 2 and removal of the spring 1, as it does not exceed 1-2, while the installation of the spring in the clamping device of the turning machine, the rotation and pushing the mandrel or the running rollers of the inner surface of the spring and the withdrawal of the spring from the fixture lathe is significantly higher than the hardening time of the proposed method.

Thus, application of the proposed method of apocalypsin 1 in a compressed state allows you to create on the inner and outer surfaces of the turns of the springs 1 compressive residual stresses, which are formed with tensile stresses that occur during operation of the spring 1 and reduce them. It is expected to increase the durability of the hardened thus springs 1.4-2 times the durability of springs, hardened by known methods, which is consistent with the (Tabanco, J. M. problems of high-speed production of springs and their solutions. Monograph / Yu. M. Tabanco. - Stavropol: OO "World data", 2007. - 152 p.) increase the durability of the springs when using a hardening plastic turns.

The present invention compared with the prototype and other known technical solutions have the following advantages:

- hardening the inner and outer surfaces of the springs produced in a compressed state;

- the highest stability of the elastic properties of springs;

- high performance peening of springs.

1. The method of hardening cylindrical helical springs, including coiling, heat treatment, shot-blasting, zanemarivanje springs or 3-5-fold compression before contact of the turns and hardening, characterized in that the coiling is produced with a pitch greater than the pitch of the finished spring, exercise luminotron and sand the ends of the heat-treated spring, and the hardening is carried out at a final stage of forming the outer and inner�th surface of the spring by pushing the tightly clad on the plunger spring compression through the die opening, the diameter of which is smaller than the diameter on the punch of the spring.

2. A method according to claim 1, characterized in that the heat treatment is carried out by release of the springs from a pre-hardened wire or by quenching and tempering of springs from hardened wire.



 

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