CN114535466A

CN114535466A - Structural design of feeding roller of thermal forming spring coiling machine

Info

Publication number: CN114535466A
Application number: CN202210092287.XA
Authority: CN
Inventors: 袁金戈; 孙希发; 张建平
Original assignee: Wuxi Jinfengyuan Spring Manufacturing Co ltd
Current assignee: Wuxi Jinfengyuan Spring Manufacturing Co ltd
Priority date: 2022-01-26
Filing date: 2022-01-26
Publication date: 2022-05-27
Anticipated expiration: 2042-01-26
Also published as: CN114535466B

Abstract

The invention discloses a structural design of a feeding roller of a thermoforming spring coiling machine, wherein the feeding roller comprises an arc-shaped trough, and the arc end of the arc-shaped trough meets the following formula: x²/D²+J²/d_max ³1, wherein d_maxIs the largest diameter size of the spring blank which can appear in coiling, and is taken as the minor axis of the ellipse, D is the major axis of the ellipse, and the size of D satisfies the following conditions: d ═ D_maxThe thermal forming spring coiling machine feeding roller structure has the advantages that the/C0S alpha is a spring helix angle, the phenomena of spring coiling strain and indentation can be effectively relieved through the thermal forming spring coiling machine feeding roller structure, the surface quality of a spring is improved, the production efficiency is further improved, and the target service life of the spring in the service process is guaranteed.

Description

Material feeding roller structural design of thermal forming spring coiling machine

Technical Field

The invention relates to the technical field of spring production, in particular to a structural design of a feeding roller of a thermal forming spring coiling machine.

Background

Surface defects of the hot-rolled spring are one of the main causes of early fatigue fracture of the spring, and therefore, it is very important to protect the outer surface of the hot-rolled spring during the production process. Burn and other mechanical damages are easy to prevent and control in the heating process of the hot-rolled spring, but the pull damage of the feeding roller to the heating blank is difficult to avoid during coil coiling.

At present, most hot coil spring manufacturers use hot coil springs, whether mechanical or two-axis numerical control coil springs, as long as the situation that a feeding roller is subjected to non-digital program control or a coil spring machine body cannot rotate exists, referring to fig. 1, a common hot coil spring rolling process is as follows: after the spring blank 3 is heated, the spring blank is manually or mechanically transmitted to a feeding end of a spring coiling machine, then a spring coiling operator sends the heated blank 3 to a position between a feeding roller 2 and a material supporting frame support, then the blank 3 is sent to a chuck of a mandrel 1 by a material clamp to be clamped and wound, and the feeding speed of the feeding roller 2 is adjusted through a numerical control instruction or a mechanical hanging wheel. Once the blank 3 is pulled by the feeding roller 2, the blank often spreads over the whole spring surface, and the surface of the spring is seriously damaged.

Disclosure of Invention

The trough shape of the commonly used feeding roller in the prior art has two types, namely a linear type and an arc type, and is referred to fig. 2, wherein fig. 2(a) is a full-containment feeding roller, fig. 2(b) is a half-containment linear feeding roller, and fig. 2(c) is a half-containment arc feeding roller. The feeding roller for the automatic feeding spring coiling machine has only one side with a raised edge and the other side is replaced by a feeding roller frame on a slide carriage, as shown in fig. 2(b) and 2(c), and also has a form with raised edges on both sides, as shown in fig. 2 (a). The above three feeding roller forms are only outside the front end supporting ring and the tail end ending ring, referring to fig. 3, the blank and the end surface of the feeding roller form an included angle, and the included angle is equal to the helix angle of the spring. Referring to fig. 3, the intersection line of the blank and the feeding roller is a part of an ellipse, so that processing the trough according to the blank circle is not in line with the actual working condition.

Referring to fig. 4, the calculation formula of the moving speed V of the spring blank on the feeding roller is as follows:

V＝σ_b×D_in×n_z

Where σ is the tensile strength of the blank, D_InIs the spring pitch diameter, n_zIs the main shaft speed of the spring coiling machine.

Rotating speed n of feeding roller_gThe calculation formula of (2) is as follows:

n_g＝D_in/D_C×n_z

In the formula D_CIs the rotary diameter of the bottom of the feeding roller trough.

Winding speed V of each point of arc groove_PThe calculation formula of (2) is as follows:

V_P＝2×σ_b×P×n_g

wherein P is the radius of gyration of the point where the arc is located.

Consequently, the linear speeds of the arcs at different radii of gyration are also unequal, and these factors all detract from the spring blank surface.

Referring to fig. 5, the feed rollers and the blanks have little effect in the feed direction and normally do not pull the blanks apart. But the pressure G between the contact surfaces of the feeding roller groove is very large, and the power on the main shaft applies bending moment to the blank through the mandrel chuck, the mandrel and the feeding roller so as to bend and form the blank. The pressure G on the surface of the blank is:

G＝3.14/32×σ/L×d³

wherein sigma is the tensile strength of the blank at the winding temperature, L is the distance from the action point of the feeding roller on the blank to the central line of the mandrel, and d is the diameter of the blank.

The contact surface of the linear trough of the feeding roller and the blank is very small, and the blank often has serious indentation and strain phenomena. From the above strain reason, under the condition that the feeding roller wheel runs normally, the strain phenomenon of the blank is solved ideally by adjusting the structural shape and the size of the trough.

The invention aims to solve the problem that a feeding roller pulls a heating blank when a spring is coiled in the prior art, and provides a feeding roller structure of a thermoforming spring coiling machine and a design method thereof. In order to achieve the purpose, the invention adopts the following technical scheme:

according to the shape of the intersecting line of the blank and the feeding roller, referring to fig. 6, the bottom surface of the trough of the feeding roller is designed to be an elliptic curve, and the equation of the elliptic curve is as follows:

X²/D²+J²/d_max ³＝1

in the formula d_maxIs a spring blank which, after heating, combines the linear expansion coefficients (also known as the thermal expansion coefficients) at a selected temperature, the largest possible rod diameter dimension of the spring blank during coiling, as the minor axis of the ellipse, and has

d_max﹦(d+es)(1+a×t)

Wherein d is the basic size of the spring material, es is the upper deviation of the diameter of the spring material, and a is the linear expansion coefficient of the spring material; t is the temperature of the spring blank at the time of winding.

Wherein D is the major axis of the ellipse and D ═ D_max/C0Sɑ

Wherein alpha is the spring helix angle.

Because the curved part at the bottom of the trough of the feeding roller is too long, the relative speed difference between the partial curved surface and the blank is increased, the blank is easy to be damaged, and the service life of the feeding roller is shortened; the curve part is too short, and the surface pressure of the blank is increased under the same pressure.

The groove depth H of the material groove of the feeding roller wheel can be selected from H to D/4-D/5 according to the bending moment of the wound spring, the groove top width is equal to the ellipse long axis D, and the material groove of the feeding roller wheel is a complete groove shape with a tangent line from the top edge of the material groove to an ellipse curve. The size of other parts of the feeding roller can be determined according to the requirement of the spring winding machine.

The invention has the beneficial effects that:

1. the invention provides the elliptic curve type feeding roller wheel according to the shape of the intersecting line of the blank and the feeding roller wheel, which can effectively relieve the phenomena of spring winding strain and indentation, improve the surface quality of the spring, further improve the production efficiency and ensure the target service life of the spring in the service process.

2. Under the condition of not changing the main body structures of the existing mechanical hot spring coiling machine and the two-axis numerical control hot spring coiling machine, the phenomena of strain and indentation in the spring forming process are improved only by optimizing and improving the structure of the feeding roller, so that the improvement cost is low, and the push and application are convenient.

Drawings

FIG. 1 is a schematic view of the present thermoformed spring coiler making;

FIG. 2 is a schematic structural view of a common feeding roller in the prior art;

FIG. 3 is a schematic view of the intersection of a blank and a feed roller;

FIG. 4 is a schematic view showing the moving direction of the feeding roller and the blank;

FIG. 5 is a schematic view of the force action of the feed rollers on the blanks;

FIG. 6 is a schematic structural view of a feeding roller in the present invention.

In the figure: 1. a mandrel; 2. feeding rollers; 3. and (3) a blank.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

In this embodiment, a mechanical hot coil spring coiling machine is used to produce a spring, and the specification of the spring is as follows:

the diameter d of the spring material is 42mm phi

Spring outside diameter D_{Outer cover}＝Φ174mm

Spring free height H₀＝315mm

The number of working turns n of the spring is 5.0

Total number of turns n1 of spring is 6.5

When the feeding roller with the linear and arc material grooves is used, the surfaces of the produced springs are seriously damaged by pulling. Only 200 finished springs which are produced at the beginning have more than half of serious strain and indentation, and need to be manually polished, thereby wasting a large amount of manpower and material resources.

The spring is a relatively thick spring with relatively small winding, the upper deviation es of the material diameter is +/-0.6, and the linear expansion coefficient a of the spring material is 18.6-10^-6The temperature of the blank at the time of winding is 900 ℃ according to the formula d_max﹦ (d + es) (1+ a × t), the maximum possible diameter dmax, i.e., the diameter of the tube can be determined

D_max＝(42+0.6)×(1+18.6×10^-6×900)＝43.30mm

The calculation formula of the spring helix angle alpha is alpha ═ tg^-1×H₀–d/(3.14×D_InX n) to obtain α ═ tg)^-1×315-42/(3.14×132×5)＝7.5°。

The major axis D of the ellipse at the bottom of the trough of the feeding roller wheel 2 is calculated by a formula:

D＝d_max/C0Sɑ＝43.3/COS7.5°＝43.67mm

the depth H of the material groove is calculated according to a formula:

H＝0.25×d＝0.25×42＝10.50mm

and obtaining the elliptic curve type trough according to the calculated data, and obtaining the whole size of the feeding roller according to the connection requirement of the spring coiling machine.

When the elliptic curve of the groove bottom of the feeding roller trough is handed over, a curved surface with an inclination angle alpha can be cut on a cylindrical surface with the diameter dmax as a sample plate, and the curved surface is very simple and convenient to sharpen or inspect. If the situation allows, the trough of the feeding roller can also be directly processed by numerical control, and a processing program is programmed according to the requirement of the pattern shape, so that the processing process has higher efficiency.

According to the principle, the surface quality of the hot-rolled spring in the forming process can be guaranteed by calculating and adjusting according to the specification of the spring to be produced, the phenomena of strain and indentation of a mechanical hot-rolled spring machine and a two-axis numerical control hot-rolled spring machine in the spring forming process are avoided, the surface quality of the spring is greatly improved, the production efficiency is improved, and the target service life of the spring in the service process is guaranteed.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. The utility model provides a thermoforming spring coiling machine pan feeding running roller structure which characterized in that, includes convex silo, the circular arc end of convex silo satisfies following formula:

X²/D²+J²/d_max ³＝1

in the formulad_maxIs the largest diameter dimension of the spring blank that is possible in the winding, as the minor axis of the ellipse, and has

d_max﹦(d+es)(1+a×t)

Wherein d is the basic size of the spring material, es is the upper deviation of the diameter of the spring material, a is the linear expansion coefficient of the spring material, and t is the temperature of the spring blank during winding;

d is the major axis of the ellipse, and the size of D satisfies:

D＝d_max/C0Sɑ

wherein alpha is the spring helix angle.

2. The material feeding roller structure of the thermoforming spring coiling machine as claimed in claim 1, wherein the groove depth H of the material feeding roller is selected from H ═ d/4-d/5;

the width of the top of the trough of the feeding roller wheel is equal to the length of the elliptic long axis D.