CN1018053B - Wedge cross rolling process for electric step shaft - Google Patents

Abstract

The present invention relates to a technique for producing eccentric stepped shafts, which uses a special insert die to change non eccentric stepped shafts to required eccentric stepped shafts. Two deformation stages from blanks to coaxial shafts and from the coaxial shafts to the eccentric shafts are both completed in one operation circle of a wedge cross rolling mill. The technique can replace die forging to produce forged pieces of the eccentric stepped shafts so as to greatly simplify the production process and improve the utilization rate of raw material and labor productivity. Produced forged pieces of the eccentric stepped shafts have no rough edge, and the productivity is 3 to 5 times higher than the die forging.

Description

Wedge cross rolling process for electric step shaft

The invention belongs to the stress metal processing industry.

Eccentric stepped shaft class part is widely used on the engineering goods such as automobile, tractor, lathe.Traditional manufacture method is to use die-forging forming, cuts edge then, and shaping needs three process to finish the forging stock manufacturing operation altogether, and operation is many, and stock utilization is low.

The clear 62-234631 patent of JP has proposed to use the technology that the cross wedge rolling method is produced eccentric stepped shaft.It is characterized in that using the mould that has the herringbone projection, blank is alternately exerted pressure, it is eccentric that it is produced.This herringbone projection, ascent stage and descending branch change violent, belong to discontinuous curve, certainly lead to shock and vibration in the work, more seriously at work, distance between the mould constantly changes, and can not guarantee that the eccentric part cross section is round, thereby the eccentric part precision is lower.This method can only be shaped the eccentric part diameter more than or equal to the eccentric shaft of dwell of cam, and its practical scope is less.

Purpose of the present invention is exactly to have the shortcoming of producing eccentric stepped shaft technology now in order to solve, and improves the eccentric stepped shaft forging precision, and it is piece heart multidiameter cross wedge rolling that consecutive periods changes that a kind of mold work surface bus is provided.

The eccentric stepped shaft cross wedge rolling that the present invention proposes, be earlier the blank that heats to be rolled into concentric multidiameter on cross wedge rolling machine, to need eccentric part distortion then, make eccentric shaft, multidiameter is shaped with one heart, eccentric stepped shaft is shaped and cuts off is to finish in a circle of milling train running, it is characterized in that: the distortion of eccentric stepped shaft is by being installed on the cross wedge rolling machine, the working surface bus is that the iron chains piece mould that consecutive periods changes is realized, this technology both can be used on the flat cross wedge rolling machine, also can be used on the cross wedge rolling mill roller.When using flat cross wedge rolling machine, the bus equation of its working surface is:

y＝-asin (x)/(r)

When selecting the double-roller type cross wedge rolling machine for use, its working surface bus equation is:

R=R _o-asin (R _O)/(r) θ

The limiting value formula of offset is:

$a_{\max }\mathrm{=\; r\; ［\; 1\; +}\frac{\mathrm{1\; +\; R}}{{\mathrm{4\; \mu }}^2\mathrm{(R\; +\; r)}}\mathrm{(\; 1\; -}\sqrt{\mathrm{1\; +\; 8\; \mu }{}^2}\mathrm{)\; ］}$

The multidiameter shaping is to rely on common cross wedge rolling to realize with one heart.The non-eccentricity part and shape and the size of eccentric part on length and diametric(al) that obtain requiring on the forging stock in this stage.When this deformation stage finishes, have particular job surface, the iron chains piece mould of bus begins effect, makes the corresponding site metal produce radial displacement, forms eccentric stepped shaft.In the workpiece rotary course, the metallic radial transfer increases gradually along with drafts and finishes gradually.For guaranteeing the smooth transition of two deformation stages, the drafts of eccentric part should be started from scratch and be increased gradually.This method can be shaped the eccentric part diameter greater than, equal, less than the eccentric stepped shaft of dwell of cam.

The working surface bus equation of iron chains piece mould, relevant with the off-centre operation diameter with the offset size, relevant with selected milling train form.When selecting flat cross wedge rolling machine for use, the working surface bus equation is the sine curve of standard, and its equation is:

y＝-asin (x)/(r) ……（1）

Wherein: a is offset (a≤a _Max)

R is the off-centre operation radius

When selecting the double-roller type cross wedge rolling machine for use, the working surface bus equation is:

R=R _o-asin (R _O)/(r) θ……（2）

Wherein: a is offset (a≤a _Max)

R is the off-centre operation radius

R _oMould wedge tip circle radius for without acceptance of persons the time.

R is a working surface bus radius.

θ is a central angle.

Coordinate and each parameter are seen accompanying drawing 1, accompanying drawing 2.Accompanying drawing 1 is a flat cross wedge rolling machine mold work surface bus schematic diagram, and accompanying drawing 2 is the mold work surface bus schematic diagram of cross wedge rolling mill roller.

The maximum a of offset _MaxCan calculate by following formula:

$a_{\max }\mathrm{=\; r\; ［\; 1\; +}\frac{R}{{\mathrm{4\; \mu }}^2\mathrm{(R\; +\; r)}}\mathrm{(\; 1\; -}\sqrt{\mathrm{1\; +\; 8\; \mu }{}^2}\mathrm{)\; ］\; \dots \dots (3)}$

Wherein: r is the off-centre operation radius

R is roll surface wedge tip circle radius for without acceptance of persons the time

μ is the coefficient of sliding friction between mould and workpiece

Because of a pair of die surface working bus bar equation is identical, as long as the adjustment of mould phase place is correct, in any moment of eccentric part work, the distance between two moulds all equals the off-centre operation diameter, thereby guarantees that the eccentric part cross section is round.

Intact for guaranteeing that eccentric part is shaped, lobbing mould drafts changes two complete cycles should occur.Period 1 finishes metallic radial and shifts, and second period is used for shaping.The non-eccentricity part of eccentric part both sides keeps in touch at the second stage and the die surface that are out of shape, but drafts is zero.

Eccentric stepped shaft cross wedge rolling of the present invention compare with existing technology have technology simple, reduce production equipment, stock utilization height, the forging precision height, the productivity ratio height, advantage such as reduce production costs.

Fig. 1 is the surperficial bus schematic diagram of flat cross wedge rolling machine iron chains piece mould;

Fig. 2 is the surperficial bus schematic diagram of the iron chains piece mould of cross wedge rolling mill roller;

Fig. 3 is " liberation " CA141 axle-spare tyre lifter part drawing;

Fig. 4 is the side view of Fig. 3;

Fig. 5 is an iron chains piece die drawing;

Fig. 6 is the profile of Fig. 5;

Fig. 7 is the cutaway view of Fig. 5;

Fig. 8 is the deformation process figure of eccentric shaft;

Fig. 9 is a dual roll type cross wedge rolling sketch;

Figure 10 is flat cross wedge rolling sketch;

Figure 11 is a wedge cross rolling deformation process sketch;

Figure 12 is liberation CA141 axle-spare tyre lifter cross wedge rolling die expanded view.

With the CA141 axle-spare tyre lifter in " liberation " truck is example.Offset is 3 millimeters, and the off-centre operation radius is 14 millimeters, selects the double-roller type cross wedge rolling machine, and then iron chains piece die worker makes surperficial bus equation and is:

R=R _o-asin (R _O)/(r) θ

Calculate eccentric limit a according to formula (3) _Max＞3, but the offset of this part can be produced with this method in the range of work.Fig. 3, Fig. 4 are part drawing.

The structure of iron chains piece mould such as Fig. 6, Fig. 7, the key of finishing the invention task is that iron chains piece mould should have correct shape and size.Iron chains piece mould is installed on the main body mould, and main body mould is installed on the cross wedge rolling machine bolster or on the roll again.

Whole forming processes of eccentric shaft as shown in Figure 8.Blank is deformed into and is desired concentric shafts in a district, and concentric shafts is out of shape under the effect of iron chains piece mould becomes eccentric shaft, and roll two deformation processes that circle are all finished.Except charging before being out of shape, pilot process is without any need for manually-operated.

The process that in a district blank deformation is become concentric multidiameter is basic wedge cross rolling deformation, and its basic principle is shown in Fig. 9,10.Fig. 9 is the double-roller type cross wedge rolling machine, and Figure 10 is flat cross wedge rolling machine.The identical mould that has wedge shaped projection of installation dimension on roll and module surface up and down, blank is placed between two modules.Mould motion drives the blank rotation, while blank rotate and be compressed and produce and extend axially, form need multidiameter.The cross section of blank and product all is round.Shown in Figure 11 is the citation form and the flow of metal process of mould.In the I section, along with the mould motion, voussoir is pressed into metal depth to be increased gradually, is the wedging section; The II section is the broadening degree for the certain width of compression distance increases process; III is a plastic section; IV is a cutting-off process, is segregation section.The eccentric part distortion is to increase a pair of lobbing iron chains piece between III section and IV section, makes the concentric shafts distortion become eccentric shaft.

Iron chains piece die worker do surperficial bus by formula (1) or (2) on wire cutting machine tool, process.The die main body material is ZG55, iron chains piece mold materials is 5CrMnMo, with this iron chains piece mould is successfully shut out axle one spare tyre lifter, and quality reaches specification requirement, compare with former technology, save steel 35%, save 0.258 kilogram, per hour produce 600 for every, boost productivity 5 times, forging key dimension precision reaches the micron order in JB3834-85 " steel forging part tolerance and the machine-finish allowance " standard, and through the macrostructure inspection, inner nothing is loose.

Claims (1)

1, a kind of cross wedge rolling of eccentric stepped shaft, blank with heating rolls into concentric multidiameter on cross wedge rolling machine earlier, to need eccentric part distortion then, make eccentric shaft, multidiameter is shaped with one heart, eccentric stepped shaft is shaped and cut-out is to finish in a circle of milling train running, and it is characterized in that: the distortion of eccentric stepped shaft is by being installed on the wedge milling train, and the iron chains piece mould with following working surface is realized, when using flat cross wedge rolling machine, the bus equation of its working surface is:

y=-asin (X)/(r) ；

When selecting the double-roller type cross wedge rolling machine for use, the bus equation of its working surface is:

R=R _o-asin (R _O)/(r) θ

The limiting value formula of offset is:

$a_{\max }\mathrm{=\; r\; ［\; 1\; +}\frac{\mathrm{1\; +\; R}}{{\mathrm{4\; \mu }}^2\mathrm{(R\; +\; r)}}\mathrm{(\; 1\; -}\sqrt{\mathrm{1\; +\; 8\; \mu }{}^2}\mathrm{)\; ］}$

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