A method of processing a shift fork

Abstract

The application discloses a processing method of a shift fork. The steps are as follows: blank preparation, heat treatment, rough machining of a thickness surface, shaft hole machining, outer circle surface machining, fine machining of the thickness surface, intermediate groove machining, key groove machining and surface treatment. The processing method ensures the processing quality and precision of the shift fork, and the shift fork obtained through the processing method has small symmetry and position error, a short processing route and high processing efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mechanical processing, and particularly relates to a processing method of a shift fork. BACKGROUND

[0002] The shift fork is a power transmission device and serves to connect and support.

[0003] The shift fork as a power transmission part involves hole shaft cooperation and cooperation between a driving part and a driven part, and the assembly mode has high requirements on the size precision of the shift fork. In the processing, if a reasonable process method cannot be used, the processing quality of the shift fork is affected.

[0004] In order to ensure the processing quality of the shift fork, the process from the blank to each feature is strictly controlled according to a reasonable process method so as to meet the quality requirements of the shift fork. SUMMARY

[0005] In view of the above requirements in the prior art, the present application provides a reasonable processing method of a shift fork.

[0006] The technical scheme adopted by the present application to solve the technical problem is: a processing method of a shift fork, which is used for processing a shift fork connected by two rocker plates with different thicknesses and a shift fork shaft, the front and rear ends of the two rocker plates are respectively circular arc surfaces with different outer diameters, the centers of the two circular arcs are respectively provided with shaft holes with different inner diameters, the shaft hole in the large circular arc penetrates the shift fork shaft and symmetrically provided with key grooves on both sides of the hole, and the method comprises the following steps:

[0007] S1, blank preparation: the blank is prepared by plasma cutting or gas cutting according to the maximum outer dimension of the part and with a 5mm allowance on the single side;

[0008] S2, heat treatment: quenching and tempering treatment is performed on the shift fork blank;

[0009] S3, thickness surface rough machining: the thickness surface of the heat-treated shift fork blank is rough milled, and the thickness surface is left with a 1-2mm finishing allowance;

[0010] S4, shaft hole machining: the large and small shaft holes on the shift fork blank are machined respectively to ensure the tolerance of the shaft holes and the relative distance between the shaft holes;

[0011] S5, outer circle surface machining: the outer circle R surface and the bevel of the large and small circular arc surfaces at the front and rear ends of the shift fork blank are machined;

[0012] S6, thickness surface finishing: the thickness surface of the shift fork blank is finished milled to remove the rough milling allowance and meet the roughness requirement;

[0013] S7, middle groove processing: cutting the middle groove on the fork blank to obtain two rocker plates with different thicknesses and a fork shaft connected between the rocker plates, and ensuring the roughness of the groove surface;

[0014] S8, keyway processing: processing the keyway of the fork, and ensuring that the roughness of the keyway surface reaches 3.2;

[0015] S9, surface treatment: galvanizing the parts except the shaft hole, the middle groove, and the keyway.

[0016] Further, in step 2, the fork blank is first preheated in a preheating furnace, and then quenched and tempered, then the preheated blank is placed in a quenching furnace at 820-860 DEG C, and after 3.5-4 h of heat preservation, it is cooled to room temperature with water, and finally it is placed in a tempering furnace at 550-600 DEG C, and after 1 h of heat preservation, it is air-cooled to room temperature.

[0017] Further, in step 6, rough milling is first performed, and then fine milling is performed during thickness surface processing.

[0018] Further, the blank is made of 45# steel, and the hardness requirement after processing is HB217-255.

[0019] Further, the large shaft hole and the small shaft hole are φ16H8 and φ10H7 respectively, and the roughness requirement is 3.2.

[0020] The present application has the beneficial effects that: the present application ensures the processing quality and precision of the fork through a reasonable process method, the symmetry and position error of the processed fork are small, the process route is short, and the processing efficiency is high. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a processing process flowchart of the fork of the present application;

[0022] Figure 2 is a side view of the fork processed by the present application;

[0023] Figure 3 is a side view of the fork processed by the present application.

[0024] The reference signs are: 1-thickness surface, 2-shaft hole, 3-outer surface, 31-R surface, 32-inclined surface, 4-middle groove, 5-keyway. EMBODIMENT

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application, and the following embodiments are used to illustrate the present application, but not to limit the scope of the present application.

[0026] As shown in the drawings, Figure 1 The embodiment of the present application discloses a processing method of a fork, and the fork to be processed is as shown inFigure 2 and Figure 3 The shift fork is connected by two rocker plates with different thicknesses and a shift fork shaft, and the front and rear ends of the two rocker plates are circular arc surfaces with different outer diameters, and the centers of the two circular arcs are respectively provided with shaft holes 2 with different inner diameters, and the shaft hole 2 in the large circular arc penetrates the shift fork shaft and is symmetrically provided with key grooves 5 on both sides of the hole.

[0027] The blank of the present application adopts 45# steel, and the hardness requirement after processing is HB217~255. The processing steps of the shift fork are specifically as follows.

[0028] S1, blank preparation: the blank is prepared by plasma cutting or gas cutting according to the maximum outer dimension of the part and leaving a margin of 5mm on the single side.

[0029] S2, heat treatment: the shift fork blank is subjected to quenching and tempering treatment. First, the shift fork blank is preheated in a preheating furnace, and then subjected to quenching and tempering treatment. Then, the preheated blank is placed in a quenching furnace at 820~860℃, and after being kept for 3.5~4h, it is cooled to room temperature by water. Finally, it is placed in a tempering furnace at 550~600℃, kept for 1h, and then air-cooled to room temperature.

[0030] S3, rough machining of thickness surface: the thickness surface 1 of the heat-treated shift fork blank is rough milled, and the thickness surface 1 is left with a finishing allowance of 1~2mm.

[0031] S4, shaft hole machining: the large and small shaft holes 2 on the shift fork blank are machined respectively, which are φ16H8 and φ10H7 respectively, and the roughness requirement is 3.2, which guarantees the tolerance of the shaft hole 2 and the relative distance between the shaft holes 2.

[0032] S5, outer circular surface 3 machining: the outer circular surface R surface 31 and the inclined surface 32 of the large and small circular arc surfaces at the front and rear ends of the shift fork blank are machined.

[0033] S6, thickness surface finishing: the thickness surface 1 of the shift fork blank is first rough milled and then fine milled to remove the rough milling allowance and meet the roughness requirement.

[0034] S7, intermediate groove machining: the intermediate groove 4 is cut on the shift fork blank to obtain two rocker plates with different thicknesses and a shift fork shaft connected between the rocker plates, and the roughness of the groove surface is guaranteed.

[0035] S8, key groove machining: the key groove 5 of the shift fork is machined, and the key groove surface roughness reaches 3.2.

[0036] S9, surface treatment: the parts except the shaft hole 2, the intermediate groove 4 and the key groove 5 are subjected to zinc plating protection.

[0037] The processing method of the present application ensures the processing quality and precision of the shift fork through a reasonable process method, the symmetry and position error of the processed shift fork are small, the process route is short, and the processing efficiency is high.

[0038] The above examples only illustrate the principles and effects of the present application and some applied embodiments. Those skilled in the art can make several modifications and improvements without departing from the concept of the present application, which are all within the protection scope of the present application.

Claims

1. A processing method of a fork, for processing a fork connected by two rocker plates of different thicknesses and a fork shaft, the front and rear ends of the rocker plates are respectively circular arc surfaces with different outer diameters, the centers of the two circular arcs are respectively provided with shaft holes (2) with different inner diameters, the shaft hole (2) in the large circular arc penetrates the fork shaft and is symmetrically provided with key grooves (5) on both sides of the hole, characterized in that: It comprises the following steps S1, cutting or gas cutting the blank according to the maximum size of the part and leaving a 5mm margin on one side; S2, quenching and tempering the shift fork blank: first, put the shift fork blank into a preheating furnace for preheating, quenching and tempering, then put the blank into a quenching furnace at 820-860℃, keep for 3.5-4h, then cool to room temperature with water, finally put it into a tempering furnace at 550-600℃, keep for 1h, then air cool to room temperature; S3, rough milling the thickness surface (1) of the shift fork blank, leaving a 1-2mm finishing margin; S4, machining the large and small shaft holes (2) on the shift fork blank respectively, ensuring the tolerance of the shaft holes (2) and the distance between the shaft holes (2); S5, machining the R surface (31) and the bevel (32) of the large and small arc surfaces at the front and rear ends of the shift fork blank; S6, finishing milling the thickness surface (1) of the shift fork blank, removing the rough milling margin; S7, cutting the middle groove (4) on the shift fork blank to obtain two rocker plates with different thicknesses and a shift fork shaft connected between the rocker plates, ensuring the roughness of the groove surface; S8, machining the keyway (5) of the shift fork, ensuring that the roughness of the keyway surface reaches 3.2; S9, galvanizing the parts except the shaft holes (2), the middle groove (4) and the keyway (5) for protection.

2. The method of claim 1, wherein, The blank is made of 45# steel, and the hardness after processing is HB217-255.

3. A method of manufacturing a fork according to claim 2, characterized in that The large and small shaft holes (2) are φ16H8 and φ10H7 respectively, and the roughness is 3.2.

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