Machining method for sun gear of planetary reducer

Abstract

The invention discloses a machining method for a sun gear of a planetary reducer. The machining method comprises the steps of gear blank machining, spline broaching, gear hobbing, tooth profile chamfering, carburizing and quenching, external grinding, hole turning, flat grinding, gear grinding and detection. An outer circle recognition groove is machined in the outer circle of the gear blank and close to the near end face A; gear broaching is conducted with the near end face A as the positioning reference; a spline taper mandrel penetrates into the spline hole, the outer circle of the sun gear top is ground through gear side positioning, and the near end face A is ground in a leaning mode; the outer circle of the ground tooth crest is clamped, the near end face A is leveled, a spline inner hole is turned, a far end face B far away from the outer circle recognition groove is turned, and then the near end face A is flatly ground with the turned far end face B as the reference; during gear grinding, the far end face B and the spline inner hole are used as positioning references; during detection, the detection direction is consistent with the positioning direction of the grinding teeth, and the far end face B faces downwards. By the adoption of the technical scheme, it is guaranteed that the gear precision of the sun gear reaches the sixth level, and the use requirements of customers are met.

Description

Technical Field

[0001] The invention relates to a method for processing a sun gear of a planetary reducer, and belongs to the technical field of mechanical processing of sun gears. Background Art

[0002] Planetary reducers are widely used in engineering machinery and new energy vehicles. The sun gear in the planetary reducer is the core component of this mechanism. The sun gear is a disc gear with a spline on the inner hole. The design requires that the inner spline tooth side is used as the detection reference, and the external tooth accuracy reaches the national standard level 6.

[0003] The sun gear is made of low-carbon alloy steel and is carburized and quenched before being ground. Deformation is inevitable after heat treatment, and repairing the internal spline flank deformation requires hard broaching equipment and a specialized broach. This is cost-prohibitive for small production runs. The current process typically involves clamping the pitch circle of the gear with an external pitch circle clamp after heat treatment, internally grinding the spline minor diameter, and then grinding the gear using an expansion tool based on the spline minor diameter. Testing is performed using an optical mandrel based on the internal spline minor diameter. While external gear accuracy can reach national standards of 6-7, testing using a spline mandrel cannot guarantee even national standards of 8-9. However, customers typically use the internal spline flank for centering, making sun gear processing a constant bottleneck. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for machining a sun gear of a planetary reducer, which ensures that the precision of an external gear wheel can reach the national standard 6 design requirement by repeated testing of the external gear wheel using a spline core shaft.

[0005] The technical solution of the present invention is: a processing method for a planetary reducer sun gear, the processing method including: gear blank processing, spline drawing, gear hobbing, tooth profile chamfering, carburizing and quenching, external grinding, hole turning, flat grinding, gear grinding and detection processes; during the gear blank processing, an outer circle identification groove is processed on its outer circle near the proximal end face A; when drawing the spline, the proximal end face A is used as a positioning reference for gear drawing.

[0006] In the aforementioned method for machining the sun gear of a planetary reducer, the external grinding process is specifically as follows: inserting the spline taper core shaft into the spline hole, positioning and grinding the outer circle of the sun gear tooth top with the tooth side, and grinding close to the end surface A.

[0007] In the aforementioned method for processing the sun gear of a planetary reducer, the hole turning and flat grinding process are specifically as follows: clamping the ground outer circle of the tooth top and the flat near end face A, turning the spline inner hole, and turning the distal end face B far from the outer circle identification groove, and then flat grinding the near end face A with the turned distal end face B as the reference.

[0008] In the aforementioned method for machining the sun gear of a planetary reducer, during the gear grinding, the distal end surface B and the spline inner hole are used as positioning references.

[0009] In the aforementioned method for machining the sun gear of a planetary reducer, during the inspection, the inspection is consistent with the positioning direction of the grinding gear, with the distal end surface B facing downward.

[0010] In the aforementioned method for processing a planetary reducer sun gear, the depth and width of the outer circle identification groove are both 0.1 mm.

[0011] Beneficial effects of the present invention: Compared with the prior art, the present invention specifies the direction of spline pulling, adopts a spline core shaft to grind the outer circle and the proximal end face A, converts the spline datum to the outer circle and the proximal end face A, replaces internal grinding with turning to process the inner spline minor diameter and turn the distal end face B, adopts an internal expansion core shaft to grind the teeth with the machined distal end face B and the spline minor diameter, the detection datum is consistent with the grinding datum, and the assembly datum is consistent with the detection datum, thereby ensuring that the gear accuracy of the sun gear reaches level 6 and meets the customer's usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the workpiece structure during the spline drawing process;

[0013] Figure 2 This is a schematic diagram of the workpiece structure during the external grinding process;

[0014] Figure 3 This is a schematic diagram of the workpiece structure during the hole turning process;

[0015] Figure 4 This is a schematic diagram of the workpiece structure during the gear grinding process;

[0016] Figure 5 Schematic diagram of the workpiece structure during the inspection process. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and examples, but they are not intended to limit the present invention.

[0018] An embodiment of the present invention: A method for processing a sun gear of a planetary reducer, the method comprising: gear blank processing, spline drawing, gear hobbing, tooth profile chamfering, carburizing and quenching, external grinding, hole turning, flat grinding, gear grinding and testing processes.

[0019] During the processing of the gear blank, an outer circle identification groove is processed on its outer circle near one end face. The mark close to the outer circle identification groove is the proximal end face A, and the mark away from the outer circle identification groove is the distal end face B.

[0020] When pulling the spline, pay attention to the pulling direction. At this time, use the proximal surface A as the positioning reference for pulling the teeth. Figure 1 shown.

[0021] The outer grinding process is specifically as follows: insert the spline taper mandrel into the spline hole, position and grind the outer circle of the sun gear tooth top with the tooth side, and grind close to the end face A, such as Figure 2 shown.

[0022] The specific process of turning holes and flat grinding is as follows: clamp the outer circle of the ground tooth top and flatten the proximal end face A, and turn the spline inner hole with the outer circle of the ground tooth top and the proximal end face A as the reference, and turn the distal end face B far from the outer circle identification groove, as shown in FIG. Figure 3 As shown. Since the external grinding process has processed the outer circle of the tooth top and the proximal end surface A to a certain precision, the workpiece runout is relatively small during the inner hole turning process, thus ensuring the final turning accuracy of the inner hole and the distal end surface B.

[0023] Then, the proximal end surface A is flat-ground with the machined distal end surface B as a reference, thereby processing the proximal end surface A to the design accuracy.

[0024] When grinding the gear, the distal end surface B and the spline inner hole are used as positioning references, such as Figure 4 As shown in the figure, since the inner hole and distal end surface B have been machined to the design accuracy, the distal end surface B and the spline inner hole are used as the positioning reference at this time to ensure that the external tooth accuracy after gear grinding meets the design requirements.

[0025] During the detection, the detection is consistent with the positioning direction of the grinding gear, such as Figure 5 As shown, the distal end face B faces downward.

[0026] The depth and width of the outer circle identification groove are both 0.1 mm. The impact of the outer circle identification groove of this size on the sun gear structure itself can be ignored.

[0027] In the method of the present invention, since the outer circle identification groove is provided, the two end faces will not be confused during the subsequent processing, thus avoiding the situation where the positioning reference is confused and incorrect. By adopting the above technical solution, the present invention ensures that the gear accuracy meets the national standard 6 design requirements when repeated testing is performed using a spline core shaft.

Claims

1. A method for processing a sun gear of a planetary reducer, characterized in that: The processing method includes: gear blank processing, spline drawing, gear hobbing, tooth profile chamfering, carburizing and quenching, external grinding, hole turning, flat grinding, gear grinding and testing processes; during the gear blank processing, an external circle identification groove is processed on its outer circle near the proximal end face A; when spline drawing, the proximal end face A is used as a positioning reference for gear drawing.

2. The method for machining a planetary reducer sun gear according to claim 1, characterized in that: The external grinding process is specifically as follows: inserting the spline taper core shaft into the spline hole, positioning and grinding the outer circle of the sun gear tooth top with the tooth side, and grinding close to the end surface A.

3. The method for machining a planetary reducer sun gear according to claim 2, wherein: The hole turning and flat grinding process is specifically as follows: clamping the ground tooth top outer circle and the near end face A, turning the spline inner hole, and turning the far end face B far away from the outer circle identification groove, and then flat grinding the near end face A with the turned far end face B as the reference.

4. The method for machining a planetary reducer sun gear according to claim 3, characterized in that: During the gear grinding, the distal end surface B and the spline inner hole are used as positioning references.

5. The method for machining a planetary reducer sun gear according to claim 4, characterized in that: During the detection, the detection is consistent with the positioning direction of the grinding gear, with the distal end surface B facing downward.

6. The method for machining a planetary reducer sun gear according to claim 1, characterized in that: The depth and width of the outer circle identification groove are both 0.1 mm.

Images