CN113927057A

CN113927057A - Processing device for changing stress condition of slender shaft

Info

Publication number: CN113927057A
Application number: CN202111295213.8A
Authority: CN
Inventors: 段爱平; 宋殿琛; 付铭; 臧磊; 林江; 李守东; 党新增; 张文平
Original assignee: Inner Mongolia First Machinery Group Corp
Current assignee: Inner Mongolia First Machinery Group Corp
Priority date: 2021-11-03
Filing date: 2021-11-03
Publication date: 2022-01-14

Abstract

The invention relates to a processing device for changing stress conditions of a slender shaft, which comprises a three-jaw chuck (1), a positioning shaft (2), a first sleeve (6) and a second sleeve (7); the three-jaw chuck (1) is fixed on one end of a positioning shaft (2), the other end of the positioning shaft (2) is inserted into one end of a sleeve (6), a bearing (3), a rear bearing (4) and an end face bearing (5) are sequentially arranged between the matching surfaces of the positioning shaft (2) and the sleeve (6), the other end of the sleeve (6) is fixedly connected with one end of a sleeve (7) through threads, and the other end of the sleeve (7) is fixedly connected with a lathe tailstock (1) (4). The invention improves the cylindricity and the surface roughness and solves the technical problem that the workpiece is clamped between the centers.

Description

Processing device for changing stress condition of slender shaft

Technical Field

The invention belongs to the technical field of machining, and particularly relates to a machining device for changing stress conditions of a slender shaft.

Background

In order to ensure the processing precision of the slender shaft 12, the slender shaft 12 has various processing modes, and various auxiliary means are provided, but the various auxiliary means can only be applied in a certain range, and particularly, no good method is provided for processing the slender shaft with small diameter. The prior art generally adopts a mode of clamping one top and adding a support in the middle: (1) when the workpiece can be turned in sections, the center frame is used for supporting the workpiece. (2) The follower rest is fixed on the saddle and moves along with the lathe tool to offset the radial cutting force.

In the processing process of the prior art, aiming at the practical effect of processing the slender shaft 12, the limitations exist: (1) before the workpiece is arranged on the center frame, a section of groove for supporting the supporting claw of the center frame is required to be turned in the middle of the blank, the surface roughness and the cylindricity error are small, and otherwise the precision of the workpiece is influenced. Due to the segmented turning, the cylindricity of the elongated shaft 12 is difficult to ensure; (2) when the follow rest is used for turning, the workpiece has downward gravity and inevitable bending, so that when the follow rest is used for turning, the workpiece is usually separated from the support claw instantaneously due to centrifugal force to be contacted to generate vibration, a bamboo-shaped excircle is easy to appear, and the quality is difficult to ensure. When the workpiece is subjected to cutting force, the workpiece is bent and vibrated due to the self weight and the centrifugal force during rotation, and the cylindricity and the surface roughness are seriously influenced. (2) In the turning process, the workpiece is heated and elongated to generate bending deformation, so that the turning is difficult to carry out, and the workpiece is clamped between the centers in serious cases.

Disclosure of Invention

The invention aims to provide a processing device for changing the stress condition of a slender shaft, which improves the cylindricity and the surface roughness and solves the technical problem that a workpiece is clamped between centers.

The technical scheme of the invention is that the processing device for changing the stress condition of the slender shaft comprises a three-jaw chuck 1, a positioning shaft 2, a front bearing 3, a rear bearing 4, an end face bearing 5, a first sleeve 6 and a second sleeve 7;

the three-jaw chuck 1 is fixed on one end of the positioning shaft 2, the other end of the positioning shaft 2 is inserted into one end of the first sleeve 6, the bearing 3, the rear bearing 4 and the end face bearing 5 are sequentially arranged between the matching surfaces of the positioning shaft 2 and the first sleeve 6, the other end of the first sleeve 6 is fixedly connected with one end of the second sleeve 7 through threads, and the other end of the second sleeve 7 is fixedly connected with the lathe tailstock 14.

The invention has the advantages that the thermal denaturation elongation of the part is completely compensated by the movement of the tailstock sleeve, thereby solving the related defects caused by the thermal denaturation problem; the double-chuck clamping is adopted, the part is tensioned, and the two ends of the part are clamped by the chucks, so that the safety production is ensured, and the operation safety coefficient is improved; the invention solves the problems that when a workpiece is subjected to cutting force, the workpiece is bent and vibrated due to the self weight and the centrifugal force during rotation, the cylindricity and the surface roughness are seriously influenced, the turning is difficult to carry out, and the workpiece is clamped between the centers in serious cases; the invention improves the processing efficiency and the processing quality, shortens the preparation time of the auxiliary tool before processing, reduces the processing difficulty of an operator and ensures convenient and reliable operation.

Drawings

FIG. 1 is a schematic structural diagram of a processing device for changing stress conditions of an elongated shaft according to the invention;

fig. 2 is a partially enlarged schematic view of fig. 1.

Detailed Description

The technical scheme of the invention is further described in detail in the following with the accompanying drawings of the specification.

As shown in figures 1 and 2, the processing device for changing the stress condition of the slender shaft comprises a three-jaw chuck 1, a positioning shaft 2, a front bearing 3, a rear bearing 4, an end face bearing 5, a first sleeve 6 and a second sleeve 7.

The three-jaw chuck 1 is fixed at one end of the positioning shaft 2 through screws, the other end of the positioning shaft 2 is inserted into one end of the sleeve 6, and a front bearing 3, a rear bearing 4 and an end face bearing 5 are sequentially arranged between matching surfaces of the positioning shaft 2 and the sleeve 6. Thereby supporting the combination body of the three-jaw chuck and the positioning shaft on the sleeve 1, and fixedly connecting the positioning shaft with the sleeve by using the end face flange. And the other end of the first sleeve 6 is fixedly connected with one end of the second sleeve 7 through threads. For convenience of processing, the other end of the first sleeve 6 is in conical surface fit with one end of the second sleeve 7. And (3) performing split machining on the matching surfaces of the first sleeve 6 and the second sleeve 7, and then fixedly connecting the other end of the second sleeve 7 with a lathe tailstock 14 through a threaded hole 8, so that the whole tensioning device is connected with the lathe tailstock 14. The tightness degree of the slender shaft 12 is adjusted by shaking the tailstock handle during processing.

The sleeve is made of 38CrSi, HRC45 and has a maximum diameter of

The sleeve is used for connecting the device with a tail seat of equipment, the structure of the right end of the sleeve is determined according to the equipment, and the split body of the first sleeve 6 and the second sleeve 7 is convenient to process and assemble.

The bearings adopt 61805, 61806 and 61804; the front bearing and the rear bearing are used for bearing radial force generated in a cutting state, and the end face bearing is used for bearing axial force which is necessary to be generated in machining.

The diameter of the three-jaw chuck 1 is

The clamping device is used for clamping the end part of a workpiece and transmitting torque.

The positioning shaft 2 plays a role in accurate positioning through the support of the front bearing, the rear bearing and the end face bearing.

The threaded hole 8 plays a role of connecting the second sleeve 7 and the tailstock together.

Because the rigidity of the slender shaft 12 is poor, in order to reduce the bending of the slender shaft 12, the radial cutting force is required to be smaller and better, the main deflection angle of the cutter is a main factor influencing the radial cutting force, and under the condition of not influencing the strength of the cutter, the main deflection angle of the cutter is required to be increased as much as possible, and the main deflection angle of the turning tool is Kr-80-93 degrees. In order to reduce cutting force and cutting heat, a larger rake angle is selected, gamma is 15-30 degrees, and a chip breaker groove of R1.5-3 is ground on the front cutter surface of a turning tool, so that chips are smoothly curled and cut. The tailstock sleeve is replaced and then the part is processed, and rough turning cutting parameters are as follows: vc is 20 m/min; f is 0.2 mm/n; ap is 0.75 mm. The finish turning cutting parameters are as follows: vc is 25 m/min; f is 0.2 mm/n; ap is 0.25 mm.

The working principle of the invention is that when in processing, two ends of the slender shaft 12 are respectively fixed on the lathe three-jaw chuck 11 and the three-jaw chuck 1, and the stress condition of the slender shaft 12 in the processing process is improved by the way that the lathe tailstock 14 drives the sleeve to tension the workpiece.

The invention changes the stress direction of the parts when the slender shaft 12 is processed, greatly increases the self rigidity of the parts, improves the processing efficiency of the slender shaft 12 and has larger popularization value; the double-chuck clamping is adopted to replace the clamping of a single chuck and a tip, and the sleeve 13 is tensioned to enable the workpiece to generate axial force, so that the influence of the axial force generated by the cutter on the workpiece is reduced, and the vibration and the bending deformation of the workpiece in the machining process are reduced; the chuck sleeve positioning shaft is supported by the front bearing, the rear bearing and the end face bearing, so that the clamping flexibility of a workpiece is improved, and the axial and radial runout of the workpiece during rotation is reduced, and the chuck sleeve positioning shaft has advancement; the invention avoids the complicated links and limitations brought by using auxiliary devices such as the follow rest, the center rest, the elastic center and the like, and is more convenient, faster and more humanized in the processing process; the invention can completely eliminate auxiliary supports such as a follow rest, a center rest and the like except the special slender shaft 12, and reduces the operation skill requirement of an operator.

Claims

1. A processing device for changing stress conditions of a slender shaft is characterized in that: the processing device comprises a three-jaw chuck (1), a positioning shaft (2), a front bearing (3), a rear bearing (4), an end face bearing (5), a first sleeve (6) and a second sleeve (7);

the three-jaw chuck (1) is fixed on one end of a positioning shaft (2), the other end of the positioning shaft (2) is inserted into one end of a sleeve (6), a bearing (3), a rear bearing (4) and an end face bearing (5) are sequentially arranged between the matching surfaces of the positioning shaft (2) and the sleeve (6), the other end of the sleeve (6) is fixedly connected with one end of a sleeve (7) through threads, and the other end of the sleeve (7) is fixedly connected with a lathe tailstock (1) (4).