CN111536219A - A gear shaft and its numerical control machining method - Google Patents

Abstract

The invention relates to the technical field of gear shafts, in particular to a gear shaft and a numerically controlled machining method thereof; the gear shaft comprises a shaft body, a step part arranged on the input end of the shaft body and a gear part arranged at the output end of the shaft body; The half gear part connected by the shaft body is composed of a driving gear part, the driving gear part has a plurality of gear teeth for meshing with the low-speed internal gear, and the half gear part has a plurality of half gears that match the gear teeth of the driving gear part tooth; the stepped part is a cylinder with a stepped surface on one side, and the end face of the stepped part is provided with a counterbore with an internal thread; the numerical control machining method uses a four-axis numerical control machine tool to process the gear shaft, which is divided into blank preprocessing, modeling, planning tool It can realize the high-precision milling of this kind of gear shaft through the steps of road, roughing, semi-finishing and finishing. Compared with the prior art, the present invention can improve the service life and stability of the gear shaft, and has high machining efficiency and machining accuracy, and good quality of finished products.

Description

A gear shaft and its numerical control machining method

technical field

The invention relates to the technical field of gear shafts, in particular to a gear shaft and a numerical control machining method thereof.

Background technique

The gear shaft is the most important supporting rotary part in construction machinery, which can realize the rotary motion of gears and other components, and can transmit torque and power over a long distance. It has the advantages of high transmission efficiency, long service life and compact structure. It has been widely used and has become one of the basic parts of construction machinery transmission. It is often used in high-speed stages to drive low-speed stage gears. At present, with the rapid development of the domestic economy and the expansion of infrastructure, there will be a new wave of demand for construction machinery. The material selection of the gear shaft has a great influence on the life and working stability, but the influence of the structural design of the gear shaft on the life and working stability cannot be ignored. This is because the lubrication of the gear shaft is an important factor to ensure its service life and working stability, and a good structural design should be able to facilitate the lubrication of the gear shaft. Gear shafts are generally lubricated by self-lubricating and external lubrication. The external lubrication method adopts oil immersion lubrication or oil injection lubrication. Although oil injection lubrication has a good heat dissipation effect, it is usually used for the gear shaft used in conjunction with the low-speed external gear. The nozzle directly sprays the lubricating oil to the low-speed external gear (the gear teeth are Outer side) meshing with the gear shaft. At present, for the gear shaft that is matched with the low-speed internal gear (the gear teeth are on the inner side) and is used vertically, due to the inconvenient arrangement of the nozzles, oil injection lubrication is rarely used, and most of them can only be used. The self-lubricating method is adopted, and the self-lubricating method needs to open oil holes on the gear shaft (for example, a gear shaft of a reduction box disclosed in Chinese patent CN207921273U), which is not allowed in some cases (such as occasions with high requirements on strength) .

In addition, with the rise of CNC machining methods, it can meet the processing of gear shafts with more diversified designs. Researching the CNC machining methods of gear shafts has practical significance for improving the processing quality and life of gear shafts.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a gear shaft and a numerical control machining method thereof in order to overcome the above-mentioned defects of the prior art. The gear shaft is suitable for oil injection lubrication to the gear shaft that is matched with the low-speed internal gear (the gear teeth are on the inside) and is used vertically, which can improve the service life and stability of the gear shaft, and has high processing efficiency and processing accuracy. Good quality.

The object of the present invention can be realized through the following technical solutions:

A first aspect of the present invention provides a gear shaft, which includes a shaft body, a stepped portion arranged at the input end of the shaft body, and a gear portion arranged at the output end of the shaft body; The gear portion is composed of a plurality of gear teeth for engaging with the low-speed internal gear, and the half gear portion has a plurality of half gear teeth that match the gear teeth of the driving gear portion; The stepped portion is a cylinder with a stepped surface on one side, and the end face of the stepped portion is provided with a counterbore with an internal thread.

As a preferred technical solution, the distance from the top of the half gear teeth of the half gear portion to the shaft center is equal to the radius of the index circle of the driving gear portion.

As a preferred technical solution, the diameter of the tooth root circle of the gear portion is smaller than the diameter of the shaft body.

As a preferred technical solution, the cylindrical diameter of the stepped portion is smaller than the diameter of the shaft body.

As a preferred technical solution, the inner thread of the counterbore is located on the inner side of the counterbore facing the end face.

A second aspect of the present invention provides a numerical control machining method for a gear shaft, comprising the following steps:

S1: Process the blank into a stepped shaft matching the gear shaft and drill the end face of one end of the stepped shaft for forming the stepped portion;

S2: According to the parameters of the gear shaft, use UG software to establish a three-dimensional model of the gear shaft;

S3: According to the gear shaft model established in step S2, establish the motion trajectory of the milling cutter for rough machining of the gear part;

S4: According to the gear shaft model established in step S2, establish the motion trajectory of the milling cutter for semi-finishing of the gear part;

S5: According to the gear shaft model established in step S2, establish the movement trajectory of the milling cutter for the finishing of the gear part;

S6: According to the shaft gear model established in step S2, establish the movement trajectory of the milling cutter for machining the stepped surface of the stepped portion;

S7: Generate the G code according to the established milling cutter motion trajectory in steps S3 to S6;

S8: Import the G code generated in step S7 into the four-axis machining center, and use the four-axis machining center to complete the machining of the gear shaft. The rough machining process of the gear part adopts cavity milling, the semi-finishing process of the gear part adopts cavity milling, and the gear part is semi-finished. The process of finishing the top adopts the depth contour milling, and the step surface machining adopts the plane contour milling.

As the preferred technical solution:

In step S3, the motion trajectory of the milling cutter for rough machining of the gear portion is milled layer by layer from top to bottom;

In step S4, the top of the cutting layer range of the milling cutter motion track for rough machining of the gear portion starts from the bottom of the rough machining cutting layer range of the gear portion;

In step S5, the movement trajectory of the milling cutter for the finishing machining of the gear portion is to select the two side surfaces of the gear teeth and the half gear teeth of the gear portion for milling until the machining of the entire gear portion is completed.

As a preferred technical solution, a milling cutter with a diameter of 1 mm is used for the rough machining of the gear part, the cutting depth of each cutter is 0.05 mm, the feed speed is 500 mm/min, the spindle speed is 6000 r/min, and the machining allowance is 0.1 mm. The bottom surface of the half tooth is in line with the side surface.

As a preferred technical solution, a milling cutter with a diameter of 0.8 mm and a lower radius of 0.1 mm is used for the semi-finishing of the gear part; the cutting depth of each cutter is 0.02 mm, the feed speed is 500 mm/min, the spindle speed is 6000 r/min, the gear teeth and half gear teeth are The side allowance is 0.1mm, and the bottom allowance of gear teeth and half gear teeth is 0.01mm.

As a preferred technical solution, a milling cutter with a diameter of 0.8 mm and a lower radius of 0.1 mm is used for the finishing of the gear part; the cutting depth of each cutter is 0.04 mm, the feed rate is 600 mm/min, the spindle speed is 3000 r/min, and the finishing allowance is 0 mm.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The gear shaft of the present invention is in an upright state during operation, and the half gear portion is positioned above the driving gear portion. In the present invention, the half gear portion is provided above the driving gear portion that meshes with the low-speed internal gear. Provides an oil injection point for the oil injection lubricated nozzle, and facilitates the arrangement of the nozzle, for example, the nozzle can be directed to the half gear part above (or above the meshing position) where the driving gear part meshes with the low-speed internal gear. When the lubricating oil is sprayed, the lubricating oil flows downward along the inter-tooth gap of the half gear teeth and flows to the driving gear part, thus playing the role of lubricating the gear pair. The lubricating effect is good, which can effectively improve the service life and working stability of the gear shaft. .

(2) The shape of the half-gear part allows the nozzle to be closer to the gear part, making it easier to arrange the nozzle, and at the same time, the spraying effect is better.

(3) The design of the step portion improves the reliability and stability of the connection between the gear shaft and the power input device.

(4) The numerical control machining method of the present invention realizes the high-precision milling of the tooth surface of the gear shaft, and is suitable for the milling of the gear. Compared with the hobbing method and the powder metallurgy method in the prior art, there is no need for forming milling cutters and milling cutters. A special machine tool can realize the machining of this kind of gear shaft, which has the characteristics of high processing efficiency and high precision, and broadens the processing method of this kind of gear shaft.

Description of drawings

Fig. 1 is the structural representation of the gear shaft of the present invention;

Fig. 2 is the structural representation of the stepped shaft of the present invention;

Fig. 3 is the schematic diagram of the movement track of the milling cutter in the rough machining process of the gear part of the present invention;

4 is a schematic diagram of the motion trajectory of the milling cutter for semi-finishing of the gear portion of the present invention;

FIG. 5 is a schematic diagram of the movement trajectory of the milling cutter for establishing the finishing machining of the gear part according to the present invention.

In the figure, 1 is the shaft body, 2 is the stepped portion, 21 is the stepped surface, 22 is the counterbore, 3 is the gear portion, 31 is the half gear portion, and 32 is the driving gear portion.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

A gear shaft, as shown in Figure 1, includes a shaft body 1, a stepped portion 2 arranged at the input end of the shaft body 1, and a gear portion 3 arranged at the output end of the shaft body 1; The gear part 31 and the driving gear part 32 are composed, the driving gear part 32 has a plurality of gear teeth for meshing with the low-speed internal gear, and the half gear part has a plurality of half gear teeth that match the gear teeth of the driving gear part 31 The stepped portion 2 is a cylinder with a stepped surface 21 on one side, and the end face of the stepped portion 21 is provided with a counterbore 22 with an internal thread.

In this embodiment, refer to Table 1 for the main parameters of the driving gear portion 32 . Further, the distance from the top of the half gear teeth of the half gear portion 31 to the shaft center is equal to the radius of the pitch circle of the drive gear portion 32, and the half gear portion 31 and the drive gear portion are left after the part above the pitch circle of the gear teeth is cut off. The sections have the same cross-sectional shape.

Table 1 Main parameters of the driving gear part

In this embodiment, the diameter of the root circle of the gear portion 3 is smaller than the diameter of the shaft body 1 . The cylindrical diameter of the stepped portion 2 is smaller than the diameter of the shaft body 1 . The inner thread of the counterbore 22 is located on the inner side of the counterbore 22 which is close to the end face.

直径

的圆柱，主动齿轮部32的长度为17.5cm，主动齿轮部32与轴身1之间连接的半齿轮部31的直径为10mm，长度为4.5cm，主动齿轮部32的主要参数为：齿数10，法相模数1，法相压力角20°，齿顶圆直径12mm，分度圆直径10mm，齿根圆直径7.5mm，径向变位系数0，齿轮副中心距及其极限偏差21.5±0.0165mm，配对齿轮齿数33，齿圈径向跳动公差-0.036mm，公法线长度变动公差0.028mm，齿形公差-0.011mm，基节极限偏差0.013mm，齿向公差0.011mm。台阶部2由长度

直径7mm的圆柱在一侧铣出1.2mm台阶面。沉孔22部分底孔深度8.6cm，M4内螺纹深度6.5cm。More specifically, in this embodiment, the shaft body 1 is the length

diameter

The length of the drive gear part 32 is 17.5cm, the diameter of the half gear part 31 connected between the drive gear part 32 and the shaft body 1 is 10mm, and the length is 4.5cm. The main parameters of the drive gear part 32 are: the number of teeth 10 , normal phase modulus 1, normal phase pressure angle 20°, tip circle diameter 12mm, indexing circle diameter 10mm, root circle diameter 7.5mm, radial displacement coefficient 0, gear pair center distance and its limit deviation 21.5±0.0165mm , The number of paired gear teeth is 33, the radial runout tolerance of the ring gear is -0.036mm, the common normal length variation tolerance is 0.028mm, the tooth profile tolerance is -0.011mm, the base section limit deviation is 0.013mm, and the tooth direction tolerance is 0.011mm. Step part 2 consists of length

A cylinder with a diameter of 7mm is milled with a 1.2mm step surface on one side. The depth of the bottom hole in the 22 part of the counterbore is 8.6cm, and the depth of the M4 internal thread is 6.5cm.

The gear shaft of the present invention is in an upright state during operation, and the half gear portion is located above the driving gear portion. In the present invention, the half gear portion is arranged above the driving gear portion that meshes with the low-speed internal gear to provide fuel injection. The lubricated nozzle provides an oil injection point and facilitates the arrangement of the nozzle. For example, the nozzle can be directed to the half gear part above (or above the meshing position) where the driving gear part meshes with the low-speed internal gear for lubricating oil. By spraying, the lubricating oil flows down along the inter-tooth gap of the half gear teeth and flows to the driving gear part, thus playing the role of lubricating the gear pair, and the lubrication effect is good, which can effectively improve the service life and working stability of the gear shaft.

The above-mentioned numerical control machining method of the gear shaft is characterized in that, it comprises the following steps:

S1: Process the blank into a stepped shaft matching the gear shaft and drill the end face of one end of the stepped shaft (see Figure 2) for forming the stepped portion;

S2: According to the gear shaft parameters, use UG software to establish a three-dimensional model of the gear shaft; more specifically, in this embodiment, the three-dimensional model of the gear shaft includes a 7mm outer circle, a depth of 6cm; an 8mm outer circle, a depth of 26cm, a modulus of 1, and a pressure angle 20°, the diameter of the tip circle is 12mm, the diameter of the index circle is 10mm, the diameter of the root circle is 7.5mm, and the depth is 17.5cm; a 10mm outer circle is formed at the connection between the drive gear part and the shaft body, with a depth of 4.5mm and a depth of 7mm. The end face of the outer circular part forms a 3.3mm bottom hole, the depth is 8.6cm, the M4 thread, the depth is 6.5cm, the 7mm outer circular part has a flat surface, and the height is 5.8mm;

S3: According to the gear shaft model established in step S2, establish the motion trajectory of the milling cutter for rough machining of the gear part, as shown in Figure 3;

S4: According to the gear shaft model established in step S2, establish the motion trajectory of the milling cutter for semi-finishing of the gear part, as shown in Figure 4;

S5: According to the gear shaft model established in step S2, establish the movement trajectory of the milling cutter for the finishing of the gear part, as shown in Figure 5;

S6: According to the shaft gear model established in step S2, establish the movement trajectory of the milling cutter for machining the stepped surface of the stepped portion;

S7: Generate the G code according to the established milling cutter motion trajectory in steps S3 to S6;

S8: Import the G code generated in step S7 into the four-axis machining center, and use the four-axis machining center to complete the machining of the gear shaft. The rough machining process of the gear part adopts cavity milling, the semi-finishing process of the gear part adopts cavity milling, and the gear part is semi-finished. The process of finishing the top adopts the depth contour milling, and the step surface machining adopts the plane contour milling.

Among them, in step S1, for the convenience of clamping and the need for tool retraction during processing, the blank needs to be made into a stepped shaft structure. Turning and drilling programs can be programmed by hand. First, the blank is processed into a stepped shaft and drilled. The hard three-jaw clamps the outer circle with a diameter of 14 mm. First, use the center to drill the center hole. The drill bit drills the bottom hole of M4 to a depth of 8.6cm, and taps M4. The depth of the tap is 6.5cm, and the thread gauge is detected. In order to save the man-hours of the machining center, ordinary machine tools can be used to process the blanks into stepped shafts and drill holes. The shape and size of the stepped shaft and the size and depth of the hole are determined by the parameters of the specific gear shaft.

More specifically: in step S3, the movement path of the milling cutter for rough machining of the gear portion is milled layer by layer from top to bottom, and the rough machining cannot be processed deep into the bottom surface due to the diameter of the tool. The steps of using a four-axis machining center to process gears are different from those of a gear hobbing machine. The processing feature of the gear hobbing machine is that the gear is continuously formed as a whole, while the processing feature of the four-axis machining center is to excavate the tooth grooves one by one, and finally form the gear; the rough machining of the gear part adopts a 1mm diameter. Milling cutter, the cutting depth of each cutter is 0.05mm, the feed rate is 500mm/min, the spindle speed is 6000r/min, and the machining allowance is 0.1mm.

In step S4, the top of the cutting layer range of the milling cutter motion track for rough machining of the gear portion starts from the bottom of the rough machining cutting layer range of the gear portion, and the top of the semi-finishing cutting layer range starts from the bottom of the rough machining cutting layer range. The tool path movement trajectory is optimized; the semi-finishing of the gear part adopts a milling cutter with a diameter of 0.8mm and a lower radius of 0.1mm; the cutting depth of each cutter is 0.02mm, the feed rate is 500mm/min, the spindle speed is 6000r/min, the gear teeth and half wheel The side allowance of the teeth is 0.1mm, and the bottom side allowance of the gear teeth and half gear teeth is 0.01mm.

In step S5, the movement path of the milling cutter for the finishing of the gear part is to select the two sides of the gear teeth and the half gear teeth for milling until the entire gear part is processed, and the finishing is further based on the previous two steps. Milling until the final effect is achieved; the gear part is finished with a milling cutter with a diameter of 0.8mm and a lower radius of 0.1mm; the cutting depth of each cutter is 0.04mm, the feed rate is 600mm/min, the spindle speed is 3000r/min, and the finishing allowance is 0mm .

The above-mentioned numerical control machining method performs the milling machining method of the gear shaft on a general four-axis numerical control machining center. By establishing the gear shaft model, and designing the milling cutter motion trajectory according to the gear shaft model. First, use a milling cutter with a diameter of 1mm to perform milling and roughing by the cavity milling method, and the machining allowance is 0.1mm. Then use a milling cutter with a diameter of 0.8mm and a lower radius of 0.1mm to perform semi-finishing by cavity milling. The gear side allowance is 0.1mm, and the bottom allowance is 0.01mm. Finally, a milling cutter with a diameter of 0.8 mm and a lower radius of 0.1 mm is used for finishing by deep contour milling, and the machining allowance is 0 mm. The method realizes the high-precision milling of the tooth surface of the gear shaft, and is suitable for the milling of the gear. Compared with the hobbing method and the powder metallurgy method in the prior art, this method can be realized without a forming milling cutter and a special machine tool. Gear shaft processing has the characteristics of high processing efficiency and high precision, which broadens the processing method of this kind of gear shaft.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (10)

1. A gear shaft is characterized by comprising a shaft body (1), a step part (2) arranged at the input end of the shaft body (1) and a gear part (3) arranged at the output end of the shaft body (1); the gear part (3) consists of a half gear part (31) and a driving gear part (32) which are sequentially connected with the shaft body (1), wherein the driving gear part (32) is provided with a plurality of gear teeth for being meshed with a low-speed stage internal gear, and the half gear part is provided with a plurality of half gear teeth matched with the gear teeth of the driving gear part (31); the step part (2) is a cylinder with a step surface (21) on one side, and a counter bore (22) with internal threads is arranged on the end surface of the step part (21).

2. Gear shaft according to claim 1, characterised in that the distance of the half-gear tooth tips of the half-gear part (31) from the axis is equal to the reference circle radius of the drive gear part (32).

3. A gear shaft according to claim 1, characterised in that the root circle diameter of the gear part (3) is smaller than the diameter of the shaft body (1).

4. Gear shaft according to claim 1, characterised in that the cylindrical diameter of the step (2) is smaller than the diameter of the shaft body (1).

5. A gear shaft according to claim 1, characterised in that the internal thread of the counter bore (22) is located on the side of the counter bore (22) which is inwardly directed towards the end face.

6. A numerical control machining method of a gear shaft is characterized by comprising the following steps:

s1: processing the blank into a stepped shaft matched with the gear shaft, and drilling a hole on the end face of one end of the stepped shaft, which is used for forming a step part;

s2: establishing a gear shaft three-dimensional model by utilizing UG software according to the gear shaft parameters;

s3: establishing a milling cutter motion track for rough machining of the gear part according to the gear shaft model established in the step S2;

s4: establishing a milling cutter motion track of the semi-finishing of the gear part according to the gear shaft model established in the step S2;

s5: establishing a milling cutter motion track for finishing the gear part according to the gear shaft model established in the step S2;

s6: according to the shaft gear model established in the step S2, establishing a milling cutter motion track for processing the step surface of the step part;

s7: generating a G code according to the milling cutter motion track established in the steps S3-S6;

s8: and (4) guiding the G code generated in the step (S7) into a four-axis machining center, and finishing the machining of the gear shaft by using the four-axis machining center, wherein the rough machining process of the gear part adopts cavity milling, the semi-finish machining process of the gear part adopts cavity milling, the finish machining process of the gear part adopts depth profile milling, and the step surface machining adopts plane profile milling.

7. The numerical control machining method of a gear shaft according to claim 6, characterized in that:

in step S3, the rough-machined milling cutter of the gear part is milled layer by layer from top to bottom;

in step S4, the top of the cutting layer range of the gear portion rough-machined milling cutter motion trajectory starts from the bottom of the gear portion rough-machined cutting layer range;

in step S5, the finish machining of the gear portion is performed by selecting the two sides of the gear tooth and the half gear tooth of the gear portion and milling the selected two sides until the machining of the entire gear portion is completed.

8. The numerical control machining method of a gear shaft according to claim 6, characterized in that the rough machining of the gear portion uses a milling cutter with a diameter of 1mm, a cutting depth of 0.05mm per cutter, a feed speed of 500mm/min, a spindle rotation speed of 6000r/min, a machining allowance of 0.1mm, and bottom surfaces and side surfaces of the gear teeth and the half gear teeth of the gear portion are coincident.

9. The numerical control machining method of a gear shaft according to claim 6, characterized in that the gear portion semi-finishing uses a milling cutter with a diameter of 0.8mm and a lower radius of 0.1 mm; the cutting depth of each cutter is 0.02mm, the feeding speed is 500mm/min, the rotating speed of the main shaft is 6000r/min, the allowance of the side surfaces of the gear teeth and the half gear teeth is 0.1mm, and the allowance of the bottom surfaces of the gear teeth and the half gear teeth is 0.01 mm.

10. The numerical control machining method of a gear shaft according to claim 6, characterized in that the gear portion is finish-machined using a milling cutter having a diameter of 0.8mm and a lower radius of 0.1 mm; the cutting depth of each cutter is 0.04mm, the feeding speed is 600mm/min, the rotating speed of the main shaft is 3000r/min, and the finishing allowance is 0 mm.

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