CN115846578A - Manufacturing process of single-stage bridge hollow half shaft - Google Patents

Abstract

The invention discloses a manufacturing process of a single-stage bridge hollow half shaft, which includes a machining process and a heat treatment process. A cold rotary forging process is provided between the machining process and the heat treatment process. The cold rotary forging process is an on-machine After the process, the hollow half-shaft rod is swiveled by using the internal rotation machine and the coreless precision cold rotary forging process. The rotary forging process is the cold swivel forging process, which is a rotary forging process carried out at room temperature. After swaging, the fibrous structure of the rod remains continuous, the incision benefit is greatly reduced, and the strength of the rod is improved. The manufacturing process of the present invention has high material utilization rate, high production efficiency, high strength of the rod and splines, and effectively saves production. Raw materials, reduce production costs.

Description

Manufacturing Technology of Hollow Half Shaft of Single-Stage Axle

technical field

The invention relates to the field of key parts of automobiles, in particular to the technical field of commercial vehicle single-stage axle axle manufacturing technology.

Background technique

The commercial vehicle drive axle half shaft is a key component in the transmission efficiency and torque of the vehicle. In the field of commercial vehicles, most of them are made of solid structural steel through a series of processes, the process is as follows: pre-piercing->forming->pier spline->piercing center hole->quenching->rough straightening->rough turning Flange->finishing bar->milling spline->intermediate frequency quenching->tempering->shot blasting->fine straightening->finishing flange->drilling holes->flaw detection->cleaning- >Inspection and marking->Packing and storage. However, the solid half shaft does not meet the development trend of energy saving, emission reduction and light weight of automobiles.

In the field of commercial vehicles, most of the hollow half shafts are manufactured by the following series of processes: 1) Flange pretreatment process: pre-pier->swing mill->center hole->car clamping position->cutting->turning End face and inner hole; 2) Shaft tube process: cutting->heating->die forging->inspection->cleaning->shot blasting; 3) Hollow half-shaft process: friction welding->turning end face, chamfering->turning Rod->Quenching and tempering->Rough straightening->Shot blasting->Rough turning flange->Finish turning->Knurled key->Intermediate frequency induction hardening->Tempering->Shot blasting->Fine straightening- >Finish turning->drilling->flaw detection->cleaning->inspection and marking->packing and storage; this process is cumbersome, high cost, low raw material utilization rate, low production efficiency, and the rod strength and toughness are not high , unable to meet the half-shaft design requirements of medium and heavy commercial vehicles.

Most of the traditional half shafts are made of solid structural steel through a series of processes. The process is as follows: pre-piercing->forming->pier spline->piercing center hole->quenching and tempering->rough alignment->rough turning flange Disc->finishing bar->milling spline->intermediate frequency quenching->tempering->shot blasting->fine straightening->finishing flange->drilling holes->flaw detection->cleaning->inspection Marking -> packing into storage. However, the solid half shaft has not met the development trend of energy saving, emission reduction and light weight of automobiles.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings in the prior art, and provide a manufacturing process for a single-stage bridge hollow half shaft. In the present invention, a cold rotary forging process is provided between the machining process and the heat treatment process. The cold rotary forging process uses an internal rotation machine after the machining process and adopts a precision cold rotary forging process without a mandrel to forge a hollow half shaft. The rod part, the rotary forging process, that is, the cold swivel forging process, is a rotary forging process performed at room temperature. After rotary forging, the fibrous structure of the rod remains continuous, the incision benefit is greatly reduced, and the strength of the rod is improved. The manufacturing process of the present invention has high utilization rate of materials, high production efficiency, high strength of rods and splines, effectively saves production raw materials, and reduces production costs.

The technical scheme that the present invention solves its technical problem to take is:

A manufacturing process of a single-stage bridge hollow half shaft, including a machining process and a heat treatment process, is characterized in that a cold rotary forging process is provided between the machining process and the heat treatment process, and the cold rotary forging process is an on-machine process. After the process, the hollow half-shaft rod is swiveled by using the internal rotation machine and the coreless precision cold rotary forging process. The rotary forging process is the cold swivel forging process, which is a rotary forging process carried out at room temperature. After rotary forging, the fibrous structure of the rod remains continuous, the incision benefit is greatly reduced, and the strength of the rod is improved.

The cold rotary forging process adopts a 455mm long extended die to forge the hollow half-shaft rod in two processes. The raw material feeding speed of the cold rotary forging process is about 1500mm/min, and the maximum cross-sectional compression ratio of the cold rotary forging is 45%, mold cone angle 8°.

The machining process includes: a) pre-piercing, b) pendulum rolling, c) punching a center hole;

The pre-pier heating temperature is 1050±50°C, the heating length is controlled above 466mm, and after the structural steel bar is heated to 950°C, a 220T pre-pier machine is used for bar pre-piercing;

The pendulum mill uses the final forging temperature of 850°C to heat-roll the pre-pierced bar material to shape the flange;

The center hole is drilled by a center drill to drill the center hole of the flange.

After the cold rotary forging process and before the heat treatment process, the end face and chamfering of the hollow half shaft rod are carried out: the end face of the rod part, and the inner diameter of the rod part is chamfered to ensure the position of the oil seal, the front part of the rod, the rear part of the rod and the flower The beating value at key 4 meets the technological requirements. For example, the maximum runout value of the welding part is 1.2mm, and other parts shall not exceed 1mm.

The heat treatment process includes quenching and tempering: high-temperature tempering after quenching the half shaft, including the first stage: placing the half shaft in a heating furnace, and the temperatures in the first, second, third, fourth and fifth zones of the heating furnace are all 860 ℃, heating time 2.3h, holding time 1h, and finally immerse the half-shaft in the quenching liquid pool with a water temperature of 44°C; the second stage: place the half-shaft in the tempering furnace, the tempering temperature is 570°C, and the time in the furnace is 1h, using cold water Cool the half-shaft until the temperature of the half-shaft drops to 40°C, then air cool naturally. Check the position of the rod oil seal, the runout value of the front part of the rod part and the rear part of the rod part. The maximum runout value of the spline position is 5mm. And detect the half-axis metallographic structure and Rockwell hardness, and control the microstructure to be sorbite 1-4 (level 2).

The heat treatment process also includes subsequent heat treatment of the machining process on the hollow half-shaft rod after quenching and tempering heat treatment, including intermediate frequency induction hardening and tempering;

Among them, intermediate frequency induction hardening adopts scanning intermediate frequency hardening machine to perform intermediate frequency induction hardening on the half shaft. The induction coil is preheated in the flange for 5s, and the water spray is delayed for 8s. The DC voltage of the coil is 437V; the DC current is 325A; the frequency is 2590HZ; the moving speed of the induction coil is 6.5mm/min, the water spray is cooled for 30s, and the effective hardening layer depth is 9mm;

Tempering: Place the half shaft in the tempering furnace, control the temperature in the furnace at 210°C±10°C, and heat and hold for 2 hours in total.

The machining process of the hollow half-shaft rod after quenching and tempering heat treatment includes rough alignment, shot blasting, rough turning flange, fine turning, and knurling.

Machining after intermediate frequency induction hardening and tempering includes: shot blasting, fine straightening, fine turning, and drilling.

The beneficial effects of the present invention are:

1. The manufacturing method of the single-stage bridge hollow half shaft of the present invention is provided with a cold rotary forging process between the machining process and the heat treatment process. The mandrel precision cold rotary forging process swivels the hollow half-shaft rod, and the rotary forging process is the cold swivel forging process, which is a rotary forging process carried out at room temperature. After rotary forging, the fibrous structure of the rod remains continuous, the incision benefit is greatly reduced, and the strength of the rod is improved. The manufacturing process of the present invention has high utilization rate of materials, high production efficiency, high strength of rods and splines, effectively saves production raw materials, and reduces production costs.

2. The cold rotary forging process of the present invention adopts a 455mm long extended die, and rotates the hollow half-shaft rod in two processes. The batching feeding speed of the cold rotary forging process is about 1500mm/min, and the maximum cross-section of the cold rotary forging is The compression rate is 45%, and the mold cone angle is 8°. The manufacturing process of the invention has high production efficiency, stable and reliable product quality and reduced production cost.

3. The forgings obtained by the swaging process of the present invention have continuous fiber streamlines, and the surface quality of the swaging parts increases with the increase in the compression of the cross-section of the blank. It is generally better than the cutting surface, and is comparable to the cutting surface. The ratio can increase the contact area between the matching parts, which is conducive to improving the matching accuracy of the parts. Due to the additional compressive force on the surface of forgings after swaging, the bending strength of such forgings is improved, coupled with the advantages of smooth surfaces, the notch effect of such forgings can be minimized, ensuring forgings are very round. .

4. Since the cross section of the cold compressed blank is accompanied by work hardening, and the degree of work hardening depends on the compression rate of the cross section of the blank, the present invention adopts cheap materials with low tensile strength to replace some high-priced materials by cold swaging, which can Change the solid structure into a hollow structure to achieve the purpose of material saving.

5. In addition, the processing accuracy is high. The accuracy of swaging depends on the compression of the cross-section of the billet, the quality of the swaging die and the diameter of the forging. The tolerance is within the range of ±0.02-±0.2mm. This precision can be matched with that of precision cutting. The maximum cross-sectional compression rate that can generally be achieved by cold swaging, such as 50% for medium carbon steel and 40%-50% for stainless steel, can be swirled for multiple passes continuously for these materials without heat treatment between passes. Thus, the production cycle can be greatly shortened.

6. In addition, some unique technological effects can be easily obtained by using swaging: for example, for inward and external local thickening, for the forming of inner and outer non-circular pipe ends, and for forming short cylinders with complex shapes , for the swaging combination of pipe fittings and solid shafts.

7. In the present invention, after the cold rotary forging process and before the heat treatment process, the end face and chamfering of the hollow half shaft rod are carried out: the end face of the rod part, and the inner diameter of the rod part is chamfered to ensure the position of the oil seal, the front part of the rod, and the rod. The runout value of the rear part and the spline position meets the process requirements.

6. The present invention adopts modulation treatment and subsequent intermediate frequency induction hardening and tempering treatment, wherein the intermediate frequency induction hardening adopts a scanning type intermediate frequency quenching machine to perform intermediate frequency induction hardening on the half shaft, and the induction coil is preheated for 5 seconds in the flange. Water spraying is delayed for 8s, the DC voltage of the coil is 437V; the DC current is 325A; the frequency is 2590HZ; the moving speed of the induction coil is 6.5mm/min, the water spray is cooled for 30s, and the effective hardening layer depth is 9mm; Furnace, the temperature in the furnace is controlled at 210°C ± 10°C, and the heating and holding time is 2 hours in total. Compared with the prior art, the utility model has high efficiency and good effect of saving energy and reducing consumption.

7. The machining process of the hollow half-shaft rod of the present invention includes pre-piercing, pendulum milling, center hole drilling, end face turning, chamfering, rough straightening, shot blasting, rough turning of flanges, fine turning, and knurling , Shot blasting, fine straightening, fine turning, drilling. Compared with the machining process of the prior art, the process is simple, the manufacturing cost is low, the efficiency is high, and the effect of energy saving and consumption reduction is good.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Among the figure, 1 hollow half shaft rod portion.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described The embodiments are only some of the embodiments of the present invention, not all of them.

As shown in Figure 1, a manufacturing process of a single-stage bridge hollow half shaft includes a machining process, a swaging process, and a heat treatment process, and is characterized in that a cold rotary forging process is provided between the machining process and the heat treatment process, The cold rotary forging process is to use the internal rotation machine after the machining process to swivel the hollow half-shaft rod 1 by adopting the precision cold rotary forging process without mandrel. The rotary forging process is the cold swivel forging process, which is carried out at room temperature rotary forging process. After rotary forging, the fibrous structure of the rod remains continuous, the incision benefit is greatly reduced, and the strength of the rod is improved.

The cold rotary forging process adopts a 455mm long extended die to forge the hollow half-shaft rod in two processes. The raw material feeding speed of the cold rotary forging process is about 1500mm/min, and the maximum cross-sectional compression ratio of the cold rotary forging is 45%, mold cone angle 8°.

The manufacturing process of the present invention has high utilization rate of materials, high production efficiency, high strength of rods and splines, effectively saves production raw materials, and reduces production costs.

In the rotary forging process, when the fed billet is in contact with the rotating die, the axial feed of the billet is accompanied by its own rotation around the axis due to the friction between the two; The continuous opening and closing, so there is sliding between the blank and the mold, so that the rotation speed of the blank is much slower than that of the mold. But it is precisely because of the existence of this speed difference that each hammering of the mold can hit different positions on the outer ring of the billet, thereby ensuring a very round forging.

1) The beneficial effects produced by the swaging process of the present invention are: the swaged forging has continuous fiber streamlines. The surface quality of swivel forgings increases with the increase in the compression of the cross-section of the blank, and is generally better than that of the cutting surface. Compared with the cutting surface, it can increase the contact area between the mating parts, which is conducive to improving the matching accuracy of the parts. . Due to the additional compressive force on the surface of forgings after swaging, the bending strength of such forgings is improved, and the advantages of smooth surface can minimize the notch effect of such forgings. Because the cross-section of the cold compression blank is accompanied by work hardening, and the degree of work hardening depends on the compression rate of the cross section of the blank, the present invention uses cheap materials with low tensile strength to replace some high-priced materials through cold swaging, which can be changed The solid structure is a hollow structure to achieve the purpose of material saving. In addition, the machining accuracy is high. The accuracy of swaging depends on the compression of the cross-section of the billet, the quality of the swaging die and the diameter of the forging. The tolerance is in the range of ±0.02-±0.2mm. This precision can be matched with that of precision cutting. The maximum cross-sectional compression rate that can generally be achieved by cold swaging, such as 50% for medium carbon steel and 40%-50% for stainless steel, can be swirled for multiple passes continuously for these materials without heat treatment between passes. Thus, the production cycle can be greatly shortened. In addition, swivel forging can be used to easily obtain some unique technological effects: for example, for inward and external local thickening, for forming inner and outer non-circular pipe ends, for forming short cylinders with complex shapes, and for forming short cylinders with complex shapes. For the swaging combination of pipe fittings and solid shafts.

The machining process includes: a) pre-piercing, b) pendulum rolling, c) punching a center hole;

The pre-pier heating temperature is 1050±50°C, the heating length is controlled above 466mm, and after the structural steel bar is heated to 950°C, a 220T pre-pier machine is used for bar pre-piercing;

The pendulum mill uses the final forging temperature of 850°C to heat-roll the pre-pierced bar material to shape the flange;

The center hole is drilled by a center drill to drill the center hole of the flange.

After the cold rotary forging process and before the heat treatment process, the end face and chamfering of the hollow half shaft rod are carried out: the end face of the rod part, and the inner diameter of the rod part is chamfered to ensure the position of the oil seal, the front part of the rod, the rear part of the rod and the flower The beating value at key 4 meets the technological requirements. For example, the maximum runout value of the welding part is 1.2mm, and other parts shall not exceed 1mm.

The heat treatment process includes quenching and tempering: high-temperature tempering after quenching the half shaft, including the first stage: placing the half shaft in a heating furnace, and the temperatures in the first, second, third, fourth and fifth zones of the heating furnace are all 860 ℃, heating time 2.3h, holding time 1h, and finally immerse the half-shaft in the quenching liquid pool with a water temperature of 44°C; the second stage: place the half-shaft in the tempering furnace, the tempering temperature is 570°C, and the time in the furnace is 1h, using cold water Cool the half-shaft until the temperature of the half-shaft drops to 40°C, then air cool naturally. Check the position of the rod oil seal, the runout value of the front part of the rod part and the rear part of the rod part. The maximum runout value of the spline position is 5mm. And detect the half-axis metallographic structure and Rockwell hardness, and control the microstructure to be sorbite 1-4 (level 2).

The heat treatment process also includes subsequent heat treatment of the machining process on the hollow half-shaft rod after quenching and tempering heat treatment, including intermediate frequency induction hardening and tempering;

Among them, intermediate frequency induction hardening adopts scanning intermediate frequency hardening machine to perform intermediate frequency induction hardening on the half shaft. The induction coil is preheated in the flange for 5s, and the water spray is delayed for 8s. The DC voltage of the coil is 437V; the DC current is 325A; the frequency is 2590HZ; the moving speed of the induction coil is 6.5mm/min, the water spray is cooled for 30s, and the effective hardening layer depth is 9mm;

Tempering: Place the half shaft in the tempering furnace, control the temperature in the furnace at 210°C±10°C, and heat and hold for 2 hours in total.

The machining process of the hollow half-shaft rod after quenching and tempering heat treatment includes rough alignment, shot blasting, rough turning flange, fine turning, and knurling.

Machining after intermediate frequency induction hardening and tempering includes: shot blasting, fine straightening, fine turning, drilling, etc. In addition, after machining, flaw detection, cleaning, inspection and marking are carried out, and then packaging and storage are carried out.

In the description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "vertical", "horizontal" etc. indicate The orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for describing the present invention and does not require that the present invention must be constructed or operated in a specific orientation, so it should not be construed as limiting the present invention. "Connection" and "connection" in the present invention should be understood in a broad sense, for example, it can be a connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component. In other words, the specific meanings of the above terms can be understood in specific situations.

The above descriptions are preferred implementations of the present invention, and the descriptions of specific examples are only used to better understand the idea of the present invention. For those skilled in the art, several improvements or equivalent replacements can be made according to the principles of the present invention, and these improvements or equivalent replacements are also deemed to fall within the protection scope of the present invention.

Claims (8)

1. A manufacturing process of a single-stage bridge hollow half shaft, comprising a machining process and a heat treatment process, characterized in that a cold rotary forging process is provided between the machining process and the heat treatment process, and the cold rotary forging process is in After the machining process, the hollow half-shaft rod is swiveled with an internal rotation machine and a precision cold rotary forging process without mandrel. 2. The manufacturing process of the single-stage bridge hollow half-shaft as claimed in claim 1, wherein the cold rotary forging process adopts a 455mm long elongated die, and swages the hollow half-shaft rod in two processes. The raw material feeding speed of the cold rotary forging process is about 1500mm/min, the maximum section compression rate of the cold rotary forging is 45%, and the die cone angle is 8°. 3. The manufacturing process of the single-stage bridge hollow half-shaft as claimed in claim 1, wherein the machining process comprises: a) pre-pier, b) pendulum milling, c) punching a center hole; The pre-pier heating temperature is 1050±50°C, the heating length is controlled above 466mm, and after the structural steel bar is heated to 950°C, a 220T pre-pier machine is used for bar pre-piercing; The pendulum mill uses the final forging temperature of 850°C to heat-roll the pre-pierced bar material to shape the flange; The center hole is drilled by a center drill to drill the center hole of the flange. 4. The manufacturing process of the single-stage bridge hollow half-shaft according to claim 1, characterized in that, after the cold rotary forging process and before the heat treatment process, the end face and chamfering of the hollow half-shaft rod are carried out: the rod part The end face, and the inner diameter of the rod is chamfered to ensure that the runout values of the oil seal, the front of the rod, the rear of the rod and the spline position meet the process requirements. 5. The manufacturing process of the single-stage bridge hollow half shaft according to claim 1, characterized in that, the heat treatment process includes quenching and tempering: quenching the half shaft and then tempering at high temperature, including the first stage: placing the half shaft Heating furnace, the temperature of zone 1, zone 2, zone 3, zone 4 and zone 5 of the furnace is 860°C, the heating time is 2.3 hours, and the holding time is 1 hour. Finally, the half shaft is immersed in a quenching liquid pool with a water temperature of 44°C; the second stage : Put the semi-shaft in the tempering furnace, the tempering temperature is 570°C, and the time in the furnace is 1h. Use cold water to cool the half-shaft until the temperature of the half-shaft drops to 40°C, and then air-cool naturally. 6. The manufacturing process of the single-stage bridge hollow half-shaft according to claim 5, characterized in that, the heat treatment process also includes the subsequent heat treatment of the machining process for the hollow half-shaft rod after quenching and tempering heat treatment, including intermediate frequency induction quenching, tempering; Among them, intermediate frequency induction hardening adopts scanning intermediate frequency hardening machine to perform intermediate frequency induction hardening on the half shaft. The induction coil is preheated in the flange for 5s, and the water spray is delayed for 8s. The DC voltage of the coil is 437V; the DC current is 325A; the frequency is 2590HZ; the moving speed of the induction coil is 6.5mm/min, the water spray is cooled for 30s, and the effective hardening layer depth is 9mm; Tempering: Place the half shaft in the tempering furnace, control the temperature in the furnace at 210°C±10°C, and heat and hold for 2 hours in total. 7. The manufacturing process of the single-stage bridge hollow half-shaft as claimed in claim 6, characterized in that the machining process of the hollow half-shaft rod after quenching and tempering heat treatment includes rough straightening, shot blasting, and rough turning of the flange , Fine turning, knurling key. 8. The manufacturing process of the single-stage bridge hollow half shaft as claimed in claim 6, wherein the machining process after intermediate frequency induction hardening and tempering includes: shot blasting, fine straightening, fine turning, and drilling.

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