CN105772621A - Determination method for coreless rod rotary forging radial feeding process parameters of car universal transmission shaft - Google Patents

Abstract

The invention relates to a determination method for coreless rod rotary forging radial feeding process parameters of a car universal transmission shaft. The determination method comprises the steps that 1, key geometric quality parameters comprising the outer diameter roundness and the inner diameter roundness of coreless rod rotary forging are determined according to the characteristics of coreless rod rotary forging; 2, the maximum feeding quantity of coreless rod rotary forging is determined according to the geometric characteristic requirements of the size and shape of a product subjected to rotary forging; 3, the maximum feeding quantity of coreless rod rotary forging is determined according to the mechanical characteristics of a material of the product subjected to rotary forging; 4, the maximum feeding quantity of coreless rod rotary forging is determined by integrating the mechanical characteristics and the geometric characteristics of the shaft product subjected to rotary forging; and 5, the minimum forging times and feeding passes during each time of feeding are determined according to the precision requirements of the product. According to the determination method for the coreless rod rotary forging radial feeding process parameters of the car universal transmission shaft, the defects of coreless rod rotary forging can be overcome, and the important process parameters of the quality of the shaft product subjected to rotary forging can be improved.

Description

Car universal drive shaft is swaged radial feed technological parameter defining method without plug

Technical field

The present invention relates to a kind of car constant-speed universal drive shaft to swage radial feed technological parameter defining method without plug.

Background technology

Swage frequently with two or more moulds, while rotating around blank external diameter making it surround, also apply high-frequency radial force to blank axle center, make blank be subject to radial compression and the process that shapes by mould molded line and axially extend.It is a kind of local and continuously, chipless and the metal forming processing technique of precision, the advantage methods such as this technique has continuous print fibre flow, shaping surface quality shaping variable-section variable thickness structure good, easy, efficiency is high, stock utilization is high have the advantages such as efficiency height, shaping surface quality is good, stock utilization is high, having obvious advantage for small size and the car constant-speed Universal drive jackshaft manufacture bearing high pulling torque, car constant-speed Universal drive jackshaft is swaged will become the main trend that jackshaft manufacture produces.

When swaging without rod, outer surface is natural shaped by three-dimensional compressive stress, inner surface tension stress, swages the inner surface quality control by radial feeds of swaging without plug without plug, and the axle durability of product most important factor of impact of swaging is axle inner surface quality of swaging.Mainly include swaging feeding passage, every time minimum number of times of swaging, every time amount of feeding etc. without plug without plug radial feed technological parameter of swaging, not only the size of axle surfaces externally and internally of swaging and circularity are affected huge without plug radial feed technological parameter of swaging, but also impact is swaged the static strength of axle product and fatigue strength further.

Summary of the invention

The present invention swages the mechanical characteristics etc. of technology characteristics, product size of swaging and form accuracy requirement and material based on car axle product of swaging, proposing a kind of car universal drive shaft to swage radial feed technological parameter defining method without plug, the method can prevent to swage the important technical parameter of axle product quality without swage defect, raising of plug.

For achieving the above object, the technical scheme is that a kind of car universal drive shaft is swaged radial feed technological parameter defining method without plug, the steps include:

(1) swage feature according to without plug, it is determined that without the crucial almost T-stable parameter that plug is swaged: external diameter circularity and internal diameter circularity；

(2) the size and dimension geometrical property requirement according to product of swaging, it is determined that without the maximum amount of feeding that plug is swaged；

(3) mechanical characteristic according to product material of swaging, it is determined that without the maximum amount of feeding that plug is swaged；

(4) comprehensively swage the mechanical characteristic of axle product and geometrical property, it is determined that swage the maximum amount of feeding without plug；

(5) according to Product Precision requirement, it is determined that feeding is minimum forges number of times and feeding passage every time.

Described external diameter circularity and internal diameter circularity are swage in the rotary swaging process circumscribed circle of axle outer surface and inner surface and the difference of inscribed circle radius, i.e. outer surface circularity and inner surface circularity, wherein:

1) outer surface circularity

For plane tup, swage shown in the polygon edge number obtained and the relation such as formula (1) swaged between outer surface circularity

In formula: the difference of outer radius in δ, i.e. the half of dimensional tolerance or circularity；N regular polygon limit number, takes the half of regular polygon limit number for just many rosette n；Swage the nominal dimension of product radius, it is assumed that for the half of inscribed circle and circumcircle radius sum；For circular arc tup, identical swaging under outer surface circularity by approximate obtaining, the number of just many rosette is the half of regular polygon limit number；

2) inner surface circularity

For plane tup, after radial feed of swaging, shown in the such as formula of the relation between inner surface circularity and radial feeds, internal-and external diameter (2)

$\begin{array}{c}\mathrm{\δ}=\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\σ}}\\ {\∫}_{-2\mathrm{\σ}}^{2\mathrm{\σ}}\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\σ}}{e}^{-\frac{{(x-r)}^2}{2{\mathrm{\σ}}^2}}dx=0.9544(\frac{\mathrm{\θ}}{360}{\mathrm{\πR}}^2-R\sin \frac{\mathrm{\θ}}{2}(R-\mathrm{\Δ}\left)\right)\end{array}---\left(2\right)$

In formula, δ is inner surface circularity；σ is the standard deviation of inner surface deformation Gauss distribution；Δ is for swaging radial feeds without plug；θ is amount of feeding central angle corresponding when being Δ；R is outer surface radius of swaging；R is inner surface radius of swaging；For circular arc tup, after radial feed of swaging, the relation between the half of inner surface circularity and radial feeds, internal-and external diameter meets formula (2).

In above-mentioned steps (3), single radial feed maximum is determined always according to without the strain of rod section and the stress-strain diagram of material, wherein, swage shown in the equivalent strain ε such as formula (3) of inwall without plug, including the strain stress on wall thickness direction_t, axial strain ε_zWith circumferential strain ε_θ:

$\mathrm{\ϵ}=\sqrt{\frac{2}{3}({\left(\ln \frac{t}{t_0}\right)}^2+{\left(\ln \frac{t}{t_0}+\ln \frac{r_m}{r_{m0}}\right)}^2+{\left(\ln \frac{r_m}{r_{m0}}\right)}^2)}---\left(3\right)$

$r_{m_0}=r_0-\frac{t_0}{2}$

$r_m=r-\frac{t}{2}$

In formula: ε is equivalent strain；t₀For the wall thickness of blank, t is the wall thickness after blank is swaged,For the equivalent redius of blank, r_mEquivalent redius after swaging for blank, r₀For the radius of blank, r is the radius of axle of swaging after blank is swaged.

The invention has the beneficial effects as follows: the method can prevent without plug swage defect, improve the important technical parameter of axle product quality of swaging.

Accompanying drawing explanation

Fig. 1 is that certain car is swaged the structure of axis blank and product and dimensional drawing；

Fig. 2 is for swaging profile without core rod type；

Fig. 3 is the left view of Fig. 2；

Fig. 4 is shaft part I minimum diameter place's tup and blank initial contact relation schematic diagram；

Fig. 5 is inner surface deformation schematic diagram in rotary swaging process.

Detailed description of the invention

Below in conjunction with accompanying drawing, the invention will be further described with embodiment.

Swaging as object with certain car constant-speed Universal drive jackshaft, material is 25CrMo4, and product structure and key dimension are as it is shown in figure 1, it has the seamless steel pipe of the wall thickness such as uiform section to be fabricated by through swaging.Swage without plug and refer to shaft part I and shaft part III, owing to they are variable-section variable wall thickness, swage shaping only by without plug.In rotary swaging process without plug, mould tup 1 radial motion directly forges workpiece 2, and workpiece 2 does circumferential movement, such as Fig. 2, shown in 3.

Swage outer surface pressurized without plug, the natural shaped tension of inner surface, without plug swage the primarily radial flowing of material, increase wall thickness, axially flowing and can ignore.Owing to swaging inner surface circularity self-assembling formation without plug, if radial feed is unreasonable cause damage after, follow-up rotary swaging process can not be repaired；Not only affect, without plug radial feed of swaging, axle outer surface quality of swaging, but also have a strong impact on axle inner surface quality of swaging, and then impact is swaged axle static strength and fatigue strength, therefore, be that control is swaged the major parameter of defect without plug radial feed of swaging.

(1) swage feature according to without plug, it is determined that the crucial almost T-stable parameter external diameter circularity swaged without plug and internal diameter circularity；

In rotary swaging process without plug, external diameter circularity and internal diameter circularity refer to the circumscribed circle of swage in rotary swaging process axle outer surface and inner surface and the difference of inscribed circle radius, and they are the important characterization parameters of the almost T-stable such as exterior surface dimension and circularity of swaging.

Swaging the outer surface of product without plug and inner surface is all approximate circle, wherein, surfaces externally and internally approximate circle is along with mould hammer-shaped difference difference to some extent.For plane mould tup, according to stress and deformation, surfaces externally and internally of swaging is regular polygon；For circular arc mold tup, surfaces externally and internally of swaging is positive rosette.Identical forges number of times, and general positive rosette surfaces externally and internally ratio of precision regular polygon is similar to high 1 times.Arc-shaped surface tup in this example, shaft part I minimum diameter place's tup and blank initial contact relation are as shown in Figure 4.

1) outer surface circularity

For plane tup, swage shown in the polygon edge number obtained and the relation such as formula (1) swaged between outer surface circularity

In formula: the difference of outer radius in δ, i.e. the half of dimensional tolerance or circularity；N regular polygon limit number, takes the half of regular polygon limit number for just many rosette n；Swage the nominal dimension of product radius, it is assumed that for the half of inscribed circle and circumcircle radius sum.

For circular arc tup, identical swaging under outer surface circularity by approximate can obtaining, the number of just many rosette is the half of regular polygon limit number.

2) inner surface circularity

Being left out axial flowing, radial feed makes wall thickness increase, internal diameter reduces.According to forging stress and geometry deformation, for plane tup, it can be assumed that inner wall deformation meets Gauss distribution within the specific limits；In the central angle of outer surface feeding, inner surface change area be the 95.44% of exterior surface area, namely Gauss distribution ± 2 σ between area (σ is the variance of Gauss distribution), as shown in Figure 5.For circular arc tup, it can be assumed that inner wall deformation meets bimodal distribution within the specific limits, it may also assume that identical radial feed, circular arc tup inner wall deformation is equal to the half of plane tup inner wall deformation.

For plane tup, after radial feed of swaging, shown in the such as formula of the relation between inner surface circularity and radial feeds, internal-and external diameter (2)

$\begin{array}{c}\mathrm{\δ}=\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\σ}}\\ {\∫}_{-2\mathrm{\σ}}^{2\mathrm{\σ}}\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\σ}}{e}^{-\frac{{(x-r)}^2}{2{\mathrm{\σ}}^2}}dx=0.9544(\frac{\mathrm{\θ}}{360}{\mathrm{\πR}}^2-R\sin \frac{\mathrm{\θ}}{2}(R-\mathrm{\Δ}\left)\right)\end{array}---\left(2\right)$

In formula, δ is inner surface circularity；σ is the standard deviation of inner surface deformation Gauss distribution；Δ is for swaging radial feeds without plug；θ is amount of feeding central angle corresponding when being Δ；R is outer surface radius of swaging；R is inner surface radius of swaging.

For circular arc tup, after radial feed of swaging, the relation between the half of inner surface circularity and radial feeds, internal-and external diameter meets formula (2).

(2) according to geometrical property requirements such as the size and dimensions of product of swaging, it is determined that without the maximum equivalent amount of feeding that plug is swaged；

For swaging without plug, if radial feed is unreasonable, inner surface circularity is excessive, and inner surface can be made a series of folds occur, and these folds eventually result in crackle of swaging.

In order to prevent inner surface from swaging fold, improving outer surface quality, radial feed not only has maximum amount of feeding requirement, and also needs to constantly successively decrease along with passage of swaging increases radial feeds in rotary swaging process.

For this example, calculating the maximum amount of feeding for plane tup, for circular arc tup, then according to forging, cross section contact area is equal carries out equivalence, obtains the maximum equivalent amount of feeding.Required precision inner surface circularity according to product of swaging less than 0.05mm, swages the maximum amount of feeding less than 0.5mm according to what formula (2) can be evaluated whether plane tup without plug, circular arc tup swage the maximum equivalent amount of feeding less than 0.5mm without plug.

(3) mechanical characteristic according to product material of swaging, it is determined that without the maximum equivalent amount of feeding that plug is swaged；

For this example, blank external diameter is 37mm, wall thickness is the seamless steel pipe of 5mm, and the minimum outer diameter of axle product of swaging is 26.5mm, is 5.25mm without the plug maximum amount of feeding of swaging in this example.

For plane tup, swaging inwall tension stress effect without plug, if tension is excessive, then may result in the generation of inner surface cracks, the generation of crackle can cause axle defect of swaging.Therefore, the mechanical property constraint of material, i.e. stress constraint are subject to without plug radial feeds.Single radial feed maximum is may determine that according to without the strain of rod section and the stress-strain diagram of material.Swage shown in the equivalent strain ε such as formula (3) of inwall without plug, including the strain stress on wall thickness direction_t, axial strain ε_zWith circumferential strain ε_θ:

$\mathrm{\ϵ}=\sqrt{\frac{2}{3}({\left(ln\frac{t}{t_0}\right)}^2+{\left(ln\frac{t}{t_0}+ln\frac{r_m}{r_{m0}}\right)}^2+{\left(ln\frac{r_m}{r_{m0}}\right)}^2)}---\left(3\right)$

$r_{m_0}=r_0-\frac{t_0}{2}$

$r_m=r-\frac{t}{2}$

In formula: ε is equivalent strain；t₀For the wall thickness of blank, t is the wall thickness after blank is swaged,For the equivalent redius of blank, r_mEquivalent redius after swaging for blank, r₀For the radius of blank, r is the radius of axle of swaging after blank is swaged.According to formula (3) and this example material model, it is possible to obtain the equivalent strain under different radial feed and stress is as shown in table 1.

Equivalent strain under the different Radial feed quantity of table 1. and stress

When swaging without plug, along with the increase of radial feed, deformation increases, and the strain of its correspondence, stress also increase therewith.When Radial feed quantity reaches 2mm, its stress reaches 710MPa, and this example material is about 710MPa at the true stress of breakaway poing, consider discrete (about 5%) of Materials Fracture stress value, the actual single radially equivalence amount of feeding is not more than 1.0mm, otherwise there will be crackle without plug inwall of swaging.

(4) comprehensively swage the mechanical characteristic of axle product and geometrical property, it is determined that swage the maximum equivalent amount of feeding without plug；

Swage axle product without in plug rotary swaging process, and the damage caused of swaging cannot be repaired in follow-up rotary swaging process, and in rotary swaging process, the maximum amount of feeding should require, meet requirement of strength again by meeting geometric.

For in this example, it is not more than 0.5mm without plug maximum equivalent radial feeds of swaging.

(5) according to Product Precision requirement, it is determined that feeding is minimum forges number of times and feeding passage every time；

When swaging, each radial feed requirement workpiece is swaged after meeting circularity and size tolerance requirements and is carried out radial feed again, and deviation from circular from otherwise can be caused to accumulate.Being 7 class precisions for this example product outside dimension, according to formula (1) it can be calculated that for circular arc tup, meet the minimum positive garland number 55 of this precision, the minimum number of times that forges is 14 times, and every time minimum number of times that forges is 14.

For this example, blank external diameter is 37mm, product minimum outer diameter 26.5mm, and maximum equivalent total feed amount is 5.25mm.For As soon as possible Promising Policy Product Precision requirement, this amount of feeding being divided into carse, medium and small three passages, the relation of each passage feed range and the amount of feeding is as shown in table 2.

Table 2 feeding passage and the single amount of feeding

Outside dimension D (mm)	31<D≤37	28<D≤31	D≤28
				Single equivalence amount of feeding Δ (mm)	Δ≤0.5	Δ≤0.3	Δ≤0.2

Claims (3)

1. a car universal drive shaft is swaged radial feed technological parameter defining method without plug, it is characterised in that the steps include:

(1) swage feature according to without plug, it is determined that without the crucial almost T-stable parameter that plug is swaged: external diameter circularity and internal diameter circularity；

(2) the size and dimension geometrical property requirement according to product of swaging, it is determined that without the maximum amount of feeding that plug is swaged；

(3) mechanical characteristic according to product material of swaging, it is determined that without the maximum amount of feeding that plug is swaged；

(4) comprehensively swage the mechanical characteristic of axle product and geometrical property, it is determined that swage the maximum amount of feeding without plug；

(5) according to Product Precision requirement, it is determined that feeding is minimum forges number of times and feeding passage every time.

2. car universal drive shaft according to claim 1 is swaged radial feed technological parameter defining method without plug, it is characterized in that: described external diameter circularity and internal diameter circularity are swage in the rotary swaging process circumscribed circle of axle outer surface and inner surface and the difference of inscribed circle radius, i.e. outer surface circularity and inner surface circularity, wherein:

1) outer surface circularity

For plane tup, swage shown in the polygon edge number obtained and the relation such as formula (1) swaged between outer surface circularity

In formula: the difference of outer radius in δ, i.e. the half of dimensional tolerance or circularity；N regular polygon limit number, takes the half of regular polygon limit number for just many rosette n；Swage the nominal dimension of product radius, it is assumed that for the half of inscribed circle and circumcircle radius sum；For circular arc tup, identical swaging under outer surface circularity by approximate obtaining, the number of just many rosette is the half of regular polygon limit number；

2) inner surface circularity

For plane tup, after radial feed of swaging, shown in the such as formula of the relation between inner surface circularity and radial feeds, internal-and external diameter (2)

$\mathrm{\δ}=\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\σ}}$

${\∫}_{-2\mathrm{\σ}}^{2\mathrm{\σ}}\frac{1}{\sqrt{2\mathrm{\π}}\mathrm{\σ}}{e}^{-\frac{{(x-r)}^2}{2{\mathrm{\σ}}^2}}dx=0.9544(\frac{\mathrm{\θ}}{360}{\mathrm{\πR}}^2-Rsin\frac{\mathrm{\θ}}{2}(R-\mathrm{\Δ}\left)\right)---\left(2\right)$

In formula, δ is inner surface circularity；σ is the standard deviation of inner surface deformation Gauss distribution；Δ is for swaging radial feeds without plug；θ is amount of feeding central angle corresponding when being Δ；R is outer surface radius of swaging；R is inner surface radius of swaging；For circular arc tup, after radial feed of swaging, the relation between the half of inner surface circularity and radial feeds, internal-and external diameter meets formula (2).

3. the car universal drive shaft described in claim 1 is swaged radial feed technological parameter defining method without plug, it is characterized in that: in above-mentioned steps (3), single radial feed maximum is determined always according to without the strain of rod section and the stress-strain diagram of material, wherein, swage shown in the equivalent strain ε such as formula (3) of inwall without plug, including the strain stress on wall thickness direction_t, axial strain ε_zWith circumferential strain ε_θ:

$\mathrm{\ϵ}=\sqrt{\frac{2}{3}({\left(\ln \frac{t}{t_0}\right)}^2+{\left(\ln \frac{t}{t_0}+\ln \frac{r_m}{r_{m0}}\right)}^2+{\left(\ln \frac{r_m}{r_{m0}}\right)}^2)}---\left(3\right)$

$r_{m_0}=r_0-\frac{t_0}{2}$

$r_m=r-\frac{t}{2}$

In formula: ε is equivalent strain；t₀For the wall thickness of blank, t is the wall thickness after blank is swaged,For the equivalent redius of blank, r_mEquivalent redius after swaging for blank, r₀For the radius of blank, r is the radius of axle of swaging after blank is swaged.