CN201461934U

CN201461934U - Blank of piston pin

Info

Publication number: CN201461934U
Application number: CN2009201022873U
Authority: CN
Inventors: 刘献丰; 王季明
Original assignee: JINGANG IC ENGING PART GROUP CO Ltd SHIJIAZHUANG
Current assignee: JINGANG IC ENGING PART GROUP CO Ltd SHIJIAZHUANG
Priority date: 2009-04-13
Filing date: 2009-04-13
Publication date: 2010-05-12
Anticipated expiration: 2019-04-13

Abstract

The utility model discloses a blank of a piston pin, which is cylindrical and is provided with an inner bore axially. The cylindrical blank is formed by cutting and machining a seamless steel tube and has a straight inner bore; and ridges on two end faces of the blank are provided with chamfers; furthermore, the blank is made of seamless steel tube, of which the flow direction of metal fibre is closely parallel to the axial direction of the blank. The blank of the piston pin of the utility model has advantages of simple process, less machining procedure and high production efficiency; the utilization rate of materials is over 80 percent; and the microfibril flow of the inner bore is continuous, which is beneficial to improving the mechanical property of the piston pin. The blank is particularly suitable for the mass production of internal combustion engine piston pins, of which inner holes are straight holes without steps.

Description

A kind of wrist pin blank

Technical field

The utility model relates to a kind of blank that is used for the component of internal-combustion engine, especially a kind of wrist pin blank of internal-combustion engine.

Background technique

Internal-combustion engine is of many uses, and it is the major impetus of automobile, engineering machinery, farm machinery, boats and ships and generator set etc.Wrist pin is one of part the most key in the internal-combustion engine, and it is used to connect piston and connecting rod in internal-combustion engine, fuel oil is burnt in high-pressure air that the pressure of explosion that produces is passed on to bent axle and work done forms power.

The general structure of wrist pin is one to have the cylindric of axial hole.The flow of wrist pin mainly comprises: make blank---roughing (drilling)---carburizing and quenching---grinding cylindrical.

The earliest, people make the wrist pin blank, adopt solid bar to make the wrist pin blank through operations such as cut-out, boring, bore hole, flat head chamfering.Carry out manufacturing procedures such as carburizing and quenching, grinding cylindrical then.The advantage of this technology is that processing technology is simple, but waste of raw materials is serious, and work efficiency is low.

Because wrist pin is the vital part that is used to connect piston and connecting rod, its comprehensive mechanical performance requires very high.And what influence mechanical property is exactly the interior tissue of metallic material.And the flow direction of the steel fiber of metallic material inside has enormous function to the performance of part.In order to obtain the contributive metal fibrous tissue of the mechanical property of wrist pin, the someone proposed the method for following manufacturing wrist pin again afterwards.

First method is to adopt solid bar to make the wrist pin blank through operations such as cut-out, annealing, flat head chamfering, pickling, phosphatization, saponification, backward and forward extrusion moulding, boring, bore holes, the backward and forward extrusion moulding is exactly to be squeezed into blind hole respectively at the two ends of solid bar, and these work are finished by special forge plant.And then manufacturing procedures such as carburizing and quenching, grinding cylindrical.This method is a kind of few technology of not having cutting, and advantage is the stock utilization height, can reach more than 70%.But its shortcoming is middle the gross weight after the extruding, needs boring, bore hole to machine away, so the flow direction of the steel fiber of blank is cut off, and endoporus step place stress is concentrated, influences the mechanical strength of wrist pin.Another shortcoming is that operation is many, and annealing time is long, and pickling, phosphatization, saponification have pollution also need handle.

Also having a kind of method is to adopt solid bar through being squeezed into cut-out, annealing, turning both ends of the surface, the exterior angle of falling two ends, centerless grinding cylindrical, pickling, phosphatization, saponification, the first time cup-shaped, annealing again, pickling, phosphatization, saponification, for the second time push elongation moulding, go step, turning both ends of the surface, fall in the two ends operation making wrist pin blank such as exterior angle.Carry out carburizing and quenching, grinding cylindrical then.This technology is except that the advantage with above-mentioned first kind of technology, and the flow direction of the steel fiber of blank is the axial direction along wrist pin substantially.Its shortcoming is more than the first method operation, and need carry out double annealing and pickling, phosphatization, saponification, and annealing time is long, and pickling, phosphatization, saponification have pollution to handle.

The wrist pin that said method is made, as shown in Figure 1.Flow to the steel fiber at blank its endoporus place in follow-up machining of this extrusion modling and to be cut off, step place stress is concentrated, and influences the mechanical strength of wrist pin.

The model utility content

The utility model technical issues that need to address provide a kind of wrist pin blank, and it helps improving the mechanical property of work efficiency and wrist pin, and suitable endoporus is the wrist pin of straight hole.

For solving the problems of the technologies described above, technical solution adopted in the utility model is:

A kind of wrist pin blank, its profile are cylindrical, and axial direction is provided with endoporus, and its endoporus that is formed by the seamless steel pipe cutting process that is shaped as is the cylindric of straight hole.

Described wrist pin blank selects for use steel fiber to flow to and the axially approaching parallel seamless steel pipe of blank.There is chamfering at the seamed edge place of both ends of the surface, and the endoporus both ends of the surface of cylinder blank are processed into chamfering, and fillet is processed at the cylindrical place of cylinder blank both ends of the surface.

Owing to adopted technique scheme, the obtained technological progress of the utility model is:

Because what the utility model wrist pin blank adopted is that seamless steel pipe is processed, so just reduced operations such as extruding, boring, bore hole in original technology, makes technology simpler, save process time; The stock utilization height can reach more than 80%; Be particularly suitable for endoporus and do not allow the production in enormous quantities of the straight hole wrist pin of step.Simultaneously, to the endoporus and the outer rounded corner at wrist pin blank two end part, can avoid the cracking of heat treatment process Tipping Center angular position.Adopt seamless steel pipe that the endoporus of wrist pin is processed into straight hole not with the level, can also avoid endoporus step place to produce stress and concentrate, in use cause too early infringement.The steel fiber trend that adopts inside is the seamless steel pipe along axial direction, can make full use of the continuous steel fiber that forms in the seamless steel pipe manufacture process and flow to, and improves the comprehensive mechanical performance of part.

Description of drawings

Fig. 1 is the wrist pin blank drawing of existing extrusion process.

Fig. 2 is the sectional view of the utility model wrist pin blank.

Wherein, 1, steel fiber, 2, cut fiber, 3, chamfering, 4, fillet, 5, straight hole, 6, step, 7, parallel fiber.

Embodiment

Below in conjunction with accompanying drawing the utility model is described in further details:

The profile of the blank that the machining piston pin is used is cylindrical, and axial direction is provided with penetrating straight hole, be by the seamless steel pipe cutting process form cylindric; The endoporus both ends of the surface of cylinder blank are processed with chamfering 3; The cylindrical place of cylinder blank both ends of the surface is processed with fillet 4; The endoporus of blank is a straight hole 5.The raw-material microstructure of making blank is selected the seamless steel pipe of the steel fiber flow direction and blank parallel to an axis for use.

After adopting blank described in the utility model, the processing process of wrist pin just is reduced to down the seamless steel pipe material---end face chamfering---carburizing and quenching---grinding cylindrical.

Adopt the technology of the blank processing straight hole wrist pin of the utility model structure to be:

1. select specification, material to meet the seamless steel pipe of wrist pin technical requirements, its diameter of bore should be corresponding with the diameter of bore of wrist pin finished product;

2. processing technology before the wrist pin heat treatment:

The long material of seamless steel pipe is sent into the numerical control multi-station working machine tool, cut off, turning both ends of the surface, the work step such as exterior angle that falls in the two ends, beat 6 seconds;

3. carrying out carburizing, quenching, tempering in the continuous heat treating furnace automatically;

4. sandblast;

5. the centerless grinding cylindrical is removed altogether at diametric(al) surplus 0.25mm, finished size tolerance≤0.005mm, surface roughness≤Ra0.1, circularity≤0.0025mm, cylindricity≤0.0025mm;

6 clean, check, pack.

Claims

1. wrist pin blank, its profile is cylindrical, axial direction is provided with endoporus, it is characterized in that: blank is the cylindric of straight hole for the endoporus that is formed by the seamless steel pipe cutting process.

2. a kind of wrist pin blank according to claim 1 is characterized in that there is chamfering at the seamed edge place of the both ends of the surface of described wrist pin blank, and the wrist pin blank is selected the seamless steel pipe of the steel fiber flow direction and blank parallel to an axis for use.