Method for machining a curve rack using a vertical milling machine

Abstract

The present application relates to a kind of processing curve rack with vertical milling machine, belong to gear manufacturing technical field.It includes the following steps: S1, the processing parameter of rack is calculated;S2, according to the parameter of curve rack processed, select arc tooth bevel gear disc-shaped cutter;S3, design sword pole;S4, the blank of rack is clamped in bench vice, and bench vice is installed on milling machine workbench;S5, disc-shaped cutter is installed on sword pole, and sword pole is installed on milling machine, cutter head is contacted with the upper surface of rack blank, and the zero of Z-axis direction is adjusted;S6, start milling machine, and make cutter feed downward, until the feed depth reaches h, then stop Z-axis direction tool-feeding;S7, expand tooth groove;S8, index processing.This method can process curve rack by vertical milling machine, and the method is simple and low in production cost.

Description

Technical Field

[0001] This invention relates to a method for machining curved racks using a vertical milling machine, belonging to the field of gear manufacturing technology. Background Technology

[0002] Curved cylindrical gear pairs are a new type of gear pair. Unlike spur cylindrical gears, the tooth lines along the gear's axial direction are replaced by circular curves instead of straight lines. This results in advantages such as better lubrication, higher load-bearing capacity, and the ability to cancel out axial forces from external loads. Currently, research on curved cylindrical gear pairs is limited to gear-to-gear meshing. For example, Chinese patent CN102275070 A discloses a machining method for small-module spiral bevel gears and hyperbolic gears. Existing technologies do not address the meshing of curved cylindrical gears with racks, especially the machining of racks that can be paired with curved cylindrical gears. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a low-cost and easy-to-operate method for machining curved racks using a vertical milling machine.

[0004] The technical solution adopted by this invention to solve its technical problem is: a method for machining curved racks using a vertical milling machine, comprising the following steps:

[0005] S1. Calculate the machining parameters of the rack;

[0006] S2. Select a spiral bevel gear disc milling cutter based on the parameters of the curved rack being machined;

[0007] S3. Design the lifting rod;

[0008] S4. Clamp the rack blank in the vise, and install the vise on the milling machine worktable.

[0009] S5. Install the disc milling cutter on the tool hanger, install the tool hanger on the milling machine, and make the milling cutter head contact the upper surface of the rack blank. Adjust the zero position in the Z-axis direction.

[0010] S6. Start the milling machine and feed the milling cutter downwards until the feed depth reaches h, then stop the Z-axis feed.

[0011] S7, Extended tooth groove;

[0012] S8, Indexing process.

[0013] In the above method, S1 calculates the rack machining parameters based on the gear meshing principle. The relationship between the gear module m and the tooth root width l can be expressed as: bmtan20°+l / 2-πm / 4=0; cutting depth h=am+bm; tooth pitch P=πm; tooth space width is πm / 2, and for standard gears, a=1, b=1.25.

[0014] In the above method, the selection of the spiral bevel gear disc milling cutter in S2 mainly considers the diameter of the milling cutter disc and the tool offset W.

[0015] In the above method, S3 involves designing the lifting rod based on the taper of the milling machine spindle inner hole, the taper of the disc milling cutter inner hole, and the geometric dimensions of the disc milling cutter mounting hole.

[0016] In the above method, S3 can be described as purchasing a lifting tool rod and making structural modifications to install the disc milling cutter on the lifting tool rod.

[0017] In the above method, after installation in S4, the center position of the rack blank should be marked and the tool should be set to ensure that the spindle centerline is at the center position of the rack.

[0018] In the above method, the tooth root width of the tooth groove processed in S6 is the tool offset distance of the disc milling cutter.

[0019] In the above method, in step S7, the tooth root width l of the rack is calculated based on the module m of the paired gear, and l ≥ W. The handwheel in the X-axis direction is adjusted, and the rack is slowly moved to the left or right by a distance S = l - W and then stopped. The tool is then retracted along the Z-axis to complete the machining of one tooth groove.

[0020] Furthermore, in step S8 of the above method, the handwheel in the X-axis direction is adjusted again to move the worktable to the right or left by a distance T = P + S, and then the next adjacent tooth groove is processed. Step S7 is repeated until all tooth grooves on the rack are processed.

[0021] The milling machine mentioned in the above method is a conventional vertical milling machine or a CNC vertical milling machine equipped with a grating ruler.

[0022] The beneficial effects of this invention are: the machining of curved racks can be completed using a vertical milling machine, the machining method is simple and convenient. In practice, only a suitable disc milling cutter needs to be selected and fixed on the machining axis of the milling machine using a tool holder. The machining parameters can be calculated using simplified formulas to complete the machining of the curved rack, which greatly reduces the machining cost and is suitable for low-cost machining applications. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the rack structure after processing according to the present invention.

[0024] Figure 2 This is a schematic diagram of the connection structure between the tool holder and the milling cutter of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of the milling cutter head of the present invention.

[0026] Figure 4This is a schematic diagram illustrating the definition of the tooth groove geometric parameters of the present invention.

[0027] Figure 5 This is a schematic diagram of the mid-section of the rack machining process of the present invention.

[0028] Figure 6 This is a schematic diagram of the structure after processing according to Embodiment 1 of the present invention.

[0029] Figure 7 This is a schematic diagram of the processed structure in Embodiment 2 of the present invention.

[0030] Figure 8 This is a schematic diagram of the processed structure in Embodiment 3 of the present invention. Detailed Implementation

[0031] The invention will be further described below with reference to the accompanying drawings.

[0032] like Figures 1 to 8 As shown, the method for machining curved racks using a vertical milling machine according to the present invention includes the following steps:

[0033] S1. Calculate the machining parameters of the rack;

[0034] S2. Select a spiral bevel gear disc milling cutter based on the parameters of the curved rack being machined;

[0035] S3. Design the lifting rod;

[0036] S4. Clamp the rack blank in the vise, and install the vise on the milling machine worktable.

[0037] S5. Install the disc milling cutter on the tool hanger, install the tool hanger on the milling machine, and make the milling cutter head contact the upper surface of the rack blank. Adjust the zero position in the Z-axis direction.

[0038] S6. Start the milling machine and feed the milling cutter downwards until the feed depth reaches h, then stop the Z-axis feed.

[0039] S7, Extended tooth groove;

[0040] S8, Indexing process. Those skilled in the art will understand that...

[0041] Preferably, in the above method, in S1, the processing parameters of the rack are calculated based on the gear meshing principle. The relationship between the gear module m and the tooth root width l can be expressed as: bmtan20°+l / 2-πm / 4=0; the cutting depth h=am+bm; the tooth pitch P=πm; the tooth space width is πm / 2, and for the standard gear formula, a=1, b=1.25. Those skilled in the art will understand that, for ease of calculation, this method actually calculates the rack processing parameters based on the gear meshing principle. Specifically, the relationship between the gear module m and the tooth root width l can be expressed as bmtan20°+l / 2-πm / 4=0, i.e., l=0.660870m; the cutting depth h=am+bm; the tooth pitch P=πm; the tooth space width is πm / 2, and for the standard gear formula, a=1, b=1.25.

[0042] Preferably, in the above method, the selection of the spiral bevel gear disc end mill in S2 mainly considers the diameter of the end mill disc and the tool offset W. Those skilled in the art will understand that, in this method, the preferred selection of the spiral bevel gear disc end mill in S2 mainly considers the diameter of the end mill disc and the tool offset W. The end mill disc diameter determines the curvature of the curved rack tooth profile; the tool offset determines the minimum root width of the tooth groove processed by the tool.

[0043] Preferably, in step S3 of the above method, the lifting rod is designed based on the taper of the milling machine spindle inner hole, the taper of the disc milling cutter inner hole, and the geometric dimensions of the disc milling cutter mounting hole. Those skilled in the art will understand that, to facilitate the fixing of the disc milling cutter, this method actually designs the lifting rod based on the taper of the milling machine spindle inner hole, the taper of the disc milling cutter inner hole, and the geometric dimensions of the disc milling cutter mounting hole, and then processes it to achieve fixing.

[0044] Preferably, in step S3 of the above method, a tool hanger can be purchased and its structure modified to accommodate the disc milling cutter. Those skilled in the art will understand that, to reduce processing costs, this method allows for the purchase of a tool hanger and subsequent structural modifications, as long as it facilitates the mounting of the disc milling cutter onto the tool hanger.

[0045] Preferably, in step S4 of the above method, after installation, a line should be drawn at the center position of the rack blank and the tool should be set to ensure that the spindle centerline is at the center position of the rack. Those skilled in the art will understand that, to ensure machining accuracy, this method preferably involves drawing a line at the center position of the rack blank and setting the tool after installation to ensure that the spindle centerline is at the center position of the rack.

[0046] Preferably, in the above method, the tooth root width of the tooth groove processed in S6 is the tool offset of the disc milling cutter. Those skilled in the art will understand that the Z-axis is driven vertically, meaning the milling cutter cuts the rack blank. Therefore, it is preferable to stop the Z-axis feed so that the tooth root width of the processed tooth groove is the tool offset of the disc milling cutter, i.e., l = W.

[0047] Preferably, in step S7 of the above method, the tooth root width l of the rack is calculated based on the module m of the mating gear, and l ≥ W. The handwheel in the X-axis direction is adjusted, and the rack is slowly moved a distance S = l - W to the left or right until it stops. The tool is then retracted along the Z-axis to complete the machining of one tooth groove. Those skilled in the art will understand that...

[0048] Preferably, in step S8 of the above method, the handwheel in the X-axis direction is adjusted again to move the worktable to the right or left by a distance T = P + S, entering the machining of the next adjacent tooth groove. Step S7 is repeated until all tooth grooves on the rack are machined. Those skilled in the art will understand that moving the worktable so that the rack blank is located at the cutting edge of the milling cutter, and repeating step S7, the machining of adjacent tooth grooves can be completed. Repeating this process completes the machining of the entire rack. Specifically, the handwheel in the X-axis direction is adjusted to move the worktable to the right or left by a distance T = P + S, entering the machining of the next adjacent tooth groove, and step S7 is repeated until all tooth grooves on the rack are machined.

[0049] Preferably, the milling machine used in the above method is a conventional vertical milling machine or a CNC vertical milling machine equipped with a linear encoder. Those skilled in the art will understand that, in order to ensure machining accuracy, this method preferably uses a conventional vertical milling machine or a CNC vertical milling machine equipped with a linear encoder, which also reduces costs.

[0050] Example 1

[0051] The parameters for the spiral bevel gear end mill disc are as follows: 3.5-inch old structure double-sided precision bevel gear disc end mill, pressure angle of 20°, No. 7.5 cutter head, 8 cutter heads, tool offset W=1, and mounting hole taper of 1:12.

[0052] When l = W = 1, the machined rack has a module m = 1.5132 mm, a total tooth height h = 3.405 mm, an extension distance S = 0 mm, and T = 4.7539 mm.

[0053] Example 2

[0054] Using the disc milling cutter in Example 1, when machining a rack with a module m = 4.0 mm, the total tooth height h = 9 mm, the extension distance S = 1.6435 mm, and T = 14.2099 mm.

[0055] Example 3

[0056] Using the disc milling cutter from Example 1, the cutter head and adjusting shims are replaced with a cutter head with a tool offset W = 2.5. When l = W = 2.5, the machined rack has a module m = 3.7829 mm, a total tooth height h = 8.5115 mm, an extension distance S = 0 mm, and T = 11.8843 mm.

[0057] In summary, the method used in Examples 1, 2 and 3 can all achieve the machining of curved racks with corresponding parameters.

Claims

1. A method for machining curved racks using a vertical milling machine, characterized in that... Includes the following steps: S1. Calculate the machining parameters of the rack; S2. Select a spiral bevel gear disc milling cutter based on the parameters of the curved rack being machined; S3. Design the lifting rod; S4. Clamp the rack blank in the vise, which is mounted on the milling machine worktable; S5. Mount the disc milling cutter on the tool hanger, mount the tool hanger on the milling machine, and make the milling cutter head contact the upper surface of the rack blank. Adjust the zero position in the Z-axis direction. S6. Start the milling machine and feed the milling cutter downwards until the feed depth reaches h, then stop the Z-axis feed. S7. Extended tooth groove; S8. Indexing process; In step S1, the machining parameters of the rack are calculated based on the gear meshing principle, including the gear module m and the tooth root width. l The relationship can be expressed as: bmtan20° + l / 2-πm / 4 = 0; cutting depth h = am+bm; tooth pitch P = πm; The tooth space width is πm / 2, and for the standard gear type, a = 1, b = 1.25; in S2, the selection of the spiral bevel gear disc milling cutter mainly considers the diameter of the milling cutter disc and the tool offset W; in S7, the tooth root width of the rack is calculated based on the module m of the paired gears. l and l ≥ W, adjust the handwheel in the X-axis direction, and slowly move it a distance S to the left or right. l - Stop at W, retract the tool along the Z-axis to complete the machining of one tooth groove; in S8, adjust the handwheel in the X-axis direction again to move the worktable to the right or left by a distance T = P + S, and enter the machining of the next adjacent tooth groove. Repeat step S7 until all tooth grooves on the rack are machined.

2. The method for machining curved racks using a vertical milling machine according to claim 1, characterized in that: In S3, the lifting rod is designed based on the taper of the milling machine spindle inner hole, the taper of the disc milling cutter inner hole, and the geometric dimensions of the disc milling cutter mounting hole.

3. The method for machining curved racks using a vertical milling machine according to claim 1, characterized in that: In S3, a lifting rod can be purchased and its structure modified to allow the disc milling cutter to be mounted on the lifting rod.

4. The method for machining curved racks using a vertical milling machine according to claim 1, characterized in that: After installation in S4, the center position of the rack blank should be marked and the tool set to ensure that the spindle centerline is at the center position of the rack.

5. The method for machining curved racks using a vertical milling machine according to claim 1, characterized in that: The tooth root width of the tooth groove processed in S6 is the tool offset distance of the disc milling cutter.

6. The method for machining curved racks using a vertical milling machine according to claim 1, characterized in that: The milling machine is a conventional vertical milling machine or a CNC vertical milling machine equipped with a grating ruler.

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