A reversing drilling process for processing hollow shafts with a rod to ensure uniform wall thickness

Abstract

The application discloses a kind of hollow shafts that are processed with bar to ensure uniform wall thickness, and the process of drilling hole is reversed, comprising the following steps: S1, cylindrical processing is carried out on the bar to be processed, so that any cross section is a circular surface and the center of the circle is located on the axis of the bar;S2, the bar is clamped by reversing, and the same drill is installed on one side of the machine tool to drill hole one and hole two from the A and B ends of the bar respectively, and the axis of hole one and the axis of hole two are on the same straight line;S3, the bar is positioned and clamped with the axis of hole one and the axis of hole two as the axis of the hollow shaft, so that the bar rotates around the axis of the hollow shaft and the outer periphery of the bar is turned to the standard wall thickness.

Description

Technical Field

[0001] This invention relates to a reversing-pair drilling process for machining hollow shafts using rods to ensure uniform wall thickness, belonging to the field of hollow shaft machining technology. Background Technology

[0002] A type of slender shaft has extremely high requirements for torsional stiffness and bending stiffness. In order to reduce weight or to set up axial flow channels, it is necessary to drill holes along the axis to process it into a hollow shaft. Examples include anti-roll torsion bars that are to be reduced in weight between train cars and bogies, and motor shafts with axial cooling oil flow channels in oil-cooled electric drives (multi-in-one electric drive gearboxes).

[0003] To ensure the torsional stiffness of the hollow shaft, the centerline of the hole drilled along the shaft's axis must coincide with the shaft's axis at the same height. In other words, the hole wall thickness must be consistent. Otherwise, when subjected to large torques or bending moments, the thin-walled sections will deform or even break.

[0004] However, in the drilling process, due to unavoidable precision errors, the drill bit axis and the machine tool machining axis (the axis of the shaft to be machined) cannot be perfectly aligned when a long drill bit is clamped. Even with extremely precise clamping, it is impossible to avoid the drill bit axis forming a slight angle with the machining axis. This angle is extremely small, and it is difficult to measure its deflection direction and the amount of offset of the end from the machining axis after clamping. However, when using a long drill bit to perform long-distance drilling, as the drilling length increases, the end of the hole axis will deviate from the machining axis in a certain direction. Since the axis of the shaft to be machined is aligned with the machining axis when clamped, the hole drilled from the shaft will be biased to one side and the hole wall on that side will be thinner. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: how to make the center line of the hollow shaft hole of the machined hollow shaft coincide with the center line of the hollow shaft.

[0006] To address the above problems, the technical solution proposed by this invention is as follows: A reversing-pair drilling process for machining hollow shafts using rods to ensure uniform wall thickness includes the following steps: S1. Perform cylindrical machining on the rod to be machined so that any cross-section is a circle and the center of the circle is located on the axis of the rod. S2. By reversing the clamping rod, use the same drill bit installed on one side of the machine tool to drill through the A and B ends of the rod respectively to make the axis line of hole one and the axis line of hole two on the same straight line. S3. Position and clamp the rod using the hollow shaft centerlines 1 and 2 as the hollow shaft centerlines, and rotate the rod around the hollow shaft centerlines to machine the outer circumference of the rod until the wall thickness at any point is the set standard wall thickness.

[0007] To ensure that the centerline of hole one and the centerline of hole two are collinear in S2, the following steps are involved: a1. Predetermine the offset direction of the drill bit during actual drilling and the offset amount y of the center x of the drill bit's exit port from the axis of the rod. a2. Based on the offset direction obtained in a1, determine the clamping direction of end A and end B of the rod to be processed, and based on the offset y obtained in a1, determine the positions of the entry point x1 at end A and the entry point x2 at end B of the rod, respectively. Ensure that the axis line of hole one and hole two drilled from the entry point x1 and entry point x2 at both ends of the rod with the same drill bit are parallel to the axis line two, and ensure that the exit port of hole one and the exit port of hole two coincide and have a common center x. a3. Drilling, including the following steps: 1) Clamp the rod according to the clamping direction at end A as determined by a2, and drill a hole from end A of the rod at the entry point x1 determined by a2; 2) Change direction: clamp the rod according to the clamping direction of end B determined by a2, and drill from end B of the rod at the entry point x2 determined by a2.

[0008] Obtaining the offset direction of the drill bit described in a1 during actual drilling and the offset y of the center x of the drill bit's exit port from the axis of the rod is achieved by using a cylindrical rod as the experimental rod and obtaining the results through drilling and measurement. The steps include: b1. Clamp the experimental rod on the machine tool and add a mark on end A of the experimental rod to indicate the clamping direction of end A; b2. Select the center of end A as the entry point x1, and drill the drill bit from the entry point x1 on the A end face of the experimental rod at that end, and drill a hole with a length equal to that of hole two as the experimental hole. b3. Use a measuring instrument to measure the orientation and thickness h of the thinnest part of the inner wall of the tool outlet port of hole 1; b4. Determine the offset direction of hole one by measuring the orientation of the thinnest point; let the radius of the experimental rod be r1 and the radius of hole one be r2, obtain the offset y of the center x of the hole one's exit port from the axis of the rod, y=r1-h-r2; based on the axial position of the hole one's exit port, as well as the offset direction and offset y of hole one, obtain the specific position of the center x of the exit port.

[0009] Furthermore, create a scaled view of the experimental rod, at least showing the entry point x1 and the center x of the exit port circle. Draw a line segment from x1 to x, and extend this line segment to end face B of the experimental rod. The intersection of this line segment and end face B is the entry point x2 of end face B. Alternatively, directly determine the entry point x2 at end B of the experimental rod from the center of end B along the offset direction determined by b4. The entry point x2 is located at a distance of 2y from the center of end B in the offset direction.

[0010] Preferably, the tool entry point x1 and tool entry point x2 are moved a distance y in the opposite direction of the offset direction so that x is located on the axis of the rod.

[0011] Mark the tool entry point x1 and tool entry point x2, as well as the clamping directions at end A and end B, on the cylindrical workpiece to be machined; or, directly input them into the control system of the intelligent machine tool.

[0012] The clamping direction at end B is the direction after the B end of the rod is reversed to the end where the drill bit is located, and then rotated 180° around the axis of the rod according to the clamping direction at end A.

[0013] The drill bit is vertically positioned, and the rod is vertically clamped to perform vertical drilling. Beneficial effects

[0014] This process ensures that the centerline of the hollow shaft hole in the machined hollow shaft is highly aligned with the centerline of the hollow shaft, thereby guaranteeing uniform wall thickness. Furthermore, since the hollow shaft is made by drilling holes in a solid rod, it ensures that the material of the entire hollow shaft is uniform, thus preventing the presence of weak points that are prone to deformation or breakage, thereby achieving the requirement of high torsional stiffness. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of the experimental rod described in Example 1; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 This is a schematic diagram of a scaled view of the experimental rod used in Example 1; Figure 4 This is a three-dimensional schematic diagram of the experimental rod described in Example 1, showing the entry point x2 at end B; Figure 5 This is a three-dimensional schematic diagram of the rod described in Embodiment 1, showing the positions of the entry points x1 and x2 at both ends of the rod A and B; Figure 6 This is a three-dimensional schematic diagram of the rod described in Embodiment 1, showing a hole drilled from the entry point x1 at end A of the rod; Figure 7This is a three-dimensional schematic diagram of the rod described in Embodiment 1, showing the second hole drilled from the entry point x2 at end B of the rod; Figure 8 This is a three-dimensional schematic diagram of the hollow shaft described in Embodiment 1; Figure 9 This is a three-dimensional schematic diagram of the rod described in Embodiment 2, showing the positions of the entry points x1 and x2 at both ends of the rod A and B; Figure 10 This is a three-dimensional schematic diagram of the rod described in Embodiment 2. The diagram shows holes one and two drilled at the entry points x1 and x2 at both ends of the rod A and B.

[0016] It should be noted that the names and reference numerals of rod 1, experimental rod 101 and the scale view 102 of the experimental rod are completely consistent. For example, the A end and B end of the rod are the same in the experimental rod and the scale view.

[0017] In the diagram: 1. Rod; 101. Experimental rod; 102. Scale view; 2. Hollow shaft; 3. Hollow shaft hole; 301. Hole 1; 302. Hole 2; 4. Hollow shaft centerline; 401. Centerline 1; 402. Centerline 2; 5. Rod centerline; 6. End A; 601. Center of End A; 602. Clamping direction of End A; 7. End B; 701. Center of End B; 702. Clamping direction of End B; 8. Tool exit port; 9. Offset direction; 10. Line segment. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1

[0019] like Figure 6 As shown in Figure 8, a reversing-pair drilling process for machining hollow shafts using rods to ensure uniform wall thickness includes the following steps: S1. Perform cylindrical machining on the rod 1 to be machined, so that any cross-section is a circle and the center of the circle is located on the axis 5 of the rod. S2. By reversing the clamping rod 1, the same drill bit installed on one side of the machine tool is used to drill through the A and B ends of the rod 1 respectively, making the axis line 401 of the first hole 301 and the axis line 402 of the second hole 302 on the same straight line. S3. Position and clamp the rod 1 using the axis 401 and axis 402 as the axis 4 of the hollow shaft 2, and rotate the rod 1 around the axis 4 of the hollow shaft to machine the outer circumference of the rod 1 until the wall thickness at any point is the set standard wall thickness.

[0020] like Figure 8As shown, hole 301 and hole 302 together form a complete hollow shaft hole 3 for a hollow shaft 2. Due to unavoidable errors in drill bit clamping and drilling, the hollow shaft axis 4 of the hollow shaft hole 3 drilled in step S2 forms an angle with the cylindrical rod axis 5, or even has no intersection. This inevitably leads to uneven wall thickness at various points in the hollow shaft hole 3. By re-turning the outer periphery of the rod with the hollow shaft axis 4 as the axis in step S3, a hollow shaft 2 with uniform wall thickness is obtained. At the same time, since the hollow shaft is made by drilling holes in a solid rod, it can ensure that the material of the entire hollow shaft is uniform, thereby ensuring that the hollow shaft will not have weak parts that are easy to deform or break, thus achieving the requirement of high torsional stiffness.

[0021] like Figure 1 As shown in Figure 3, achieving the goal of making the centerline 401 of hole 301 and the centerline 402 of hole 302 collinear in step S2 above includes the following steps: a1. Predetermine the offset direction of the drill bit during actual drilling and the offset amount y of the center x of the drill bit's exit port 8 from the axis of the rod 1. a2. Based on the offset direction 9 obtained in a1, determine the clamping direction 602 at end A and the clamping direction 702 at end B of the rod 1 to be processed. Based on the offset amount y obtained in a1, determine the positions of the tool entry point x1 at end A and the tool entry point x2 at end B of the rod 1. Ensure that the axis 401 of the holes 301 and 302 drilled from the tool entry points x1 and x2 at both ends of the rod 1 with the same drill bit is parallel to the axis 402. Ensure that the tool exit port 8 of the holes 301 and 302 coincide and have a common center x. a3. Drilling, including the following sub-steps (e.g.) Figure 6 , 7 (as shown) 1) Clamp rod 1 in the clamping direction 602 at end A as determined by a2, and drill a hole from end A of rod 1 at the entry point x1 determined by a2; 2) Change direction, clamp rod 1 according to the clamping direction 702 of end B determined by a2, and drill from end B of rod 1 according to the entry point x2 determined by a2.

[0022] like Figure 7 As shown, since the center of the tool outlet of hole 301 is on axis line 401 and the center of the tool outlet of hole 302 is on axis line 402, and axis line 401 and axis line 402 are parallel, the center of the tool outlet of hole 301 and the center of the tool outlet of hole 302 coincide at a point x, and hole 301 and hole 302 become a complete hollow shaft hole 3.

[0023] like Figure 1 , 2As shown in Figure 4, obtaining the offset direction 9 of the drill bit described in a1 during actual drilling and the offset y of the center x of the drill bit's exit port 8 from the axis 5 of the rod 1 is achieved by using a cylindrical rod 1 as the experimental rod 101, through drilling and measurement, including the following steps: b1. Clamp the experimental rod 101 on the machining tool and add a mark on end A of the experimental rod 101 to indicate the clamping direction 602 at end A; b2. Select the center 601 of end A as the entry point x1, and drill the drill bit from the entry point x1 of end A of the experimental rod 101 at the end, and drill out a hole 301 with a length equal to that of hole 2 302 as the experimental hole. b3. Use a measuring instrument to measure the orientation and thickness h of the thinnest part of the inner wall of the tool outlet 8 of hole 301; b4. Determine the offset direction 9 of hole 301 by measuring the orientation of the thinnest point; Let the radius of the experimental rod 101 be r1 and the radius of hole 301 be r2, and obtain the offset y of the center x of the hole 301 from the axis 5 of the rod, y = r1 - h - r2. Based on the axial position of the tool outlet port 8 of hole 301, and the offset direction and offset amount y of hole 301, the specific position of the center x of the tool outlet port is obtained.

[0024] Further measure one: like Figure 3 As shown, a scale view 102 of the experimental rod 101 is made, at least the entry point x1 and the center x of the exit port are reflected in the scale view 102. A line segment 10 from x1 to x is drawn, and the line segment 10 is extended to the B end face of the experimental rod 101. The intersection of the line segment 10 with the B end face is the entry point x2 of the B end face.

[0025] Further measure two: like Figure 4 As shown, the tool entry point x2 is determined directly at the B end of the experimental rod 101, from the center 701 of the B end circle, according to the offset direction 9 determined by b4. The tool entry point x2 is located at a distance of 2y from the center 701 of the B end circle in the offset direction 9.

[0026] like Figure 5 As shown, the tool entry point x1 and the tool entry point x2 obtained by the above two methods, as well as the clamping direction 602 at end A and the clamping direction 702 at end B, are marked on the cylindrical rod to be machined; or, directly input into the control system of the intelligent machine tool.

[0027] like Figure 3 , 7 As shown, the above-mentioned clamping direction 702 at end B is the direction after end B of rod 1 is reversed to the end where the drill bit is located, and then rotated 180° around the rod axis 5 of rod 1 according to the clamping direction 602 at end A.

[0028] like Figure 6 , 7 As shown, by clamping the rod 1 in the clamping direction at end A and drilling hole 301 from the entry point x1, and then changing the direction to clamp the rod 1 in the clamping direction at end B and drilling hole 302 from the entry point x2, the machining of the complete hollow shaft hole 3 of the rod 1 is completed.

[0029] To eliminate gravitational interference, under permissible conditions, it is preferable to set the drill bit vertically and clamp the rod 1 vertically to carry out vertical drilling. Example 2

[0030] like Figure 9 , 10 As shown, the difference from Embodiment 1 is that the tool entry point x1 and tool entry point x2 determined in Embodiment 1 are moved a distance y in the opposite direction of the offset direction 9, so that x is located on the axis of the rod 1. In this way, it is possible to enter the tool from both sides of the axis of the rod 5. Compared with Embodiment 1, which only enters the tool from one side of the axis of the rod 5, the turning amount of the hollow shaft 2 can be reduced, and the diameter of the rod 1 can be reduced.

[0031] The above embodiments are only used to describe the present invention more clearly, and should not be regarded as limiting the scope of protection covered by the present invention. Any equivalent modifications should be regarded as falling within the scope of protection covered by the present invention.

Claims

1. A reversing-pair drilling process for machining hollow shafts using rods to ensure uniform wall thickness, characterized in that, Includes the following steps: S1. Perform cylindrical machining on the rod (1) to be machined, so that any cross-section is a circle and the center of the circle is located on the axis (5) of the rod. S2. By reversing the clamping rod (1), the same drill bit installed on one side of the machine tool is used to drill through the A and B ends of the rod (1) respectively to form a through hole 1 (301) and a through hole 2 (302), and make the axis line 1 (401) of hole 1 (301) and the axis line 2 (402) of hole 2 (302) on the same straight line. S3. Position and clamp the rod (1) with the hollow shaft centerline (4) of the hollow shaft (2) using the first axis (401) and the second axis (402) as the centerline (4), so that the rod (1) can be rotated around the hollow shaft centerline (4) and the outer periphery of the rod (1) can be machined to the wall thickness of any point as the set standard wall thickness. To ensure that the centerline of hole one (301) and the centerline of hole two (302) are on the same straight line in S2, the following steps are included: a1. Predetermine the offset direction of the drill bit during actual drilling and the offset amount y of the center x of the drill bit's exit port (8) from the axis (5) of the rod; a2. Based on the offset direction obtained from a1, determine the clamping direction (602) of the A end and the clamping direction (702) of the rod (1) to be processed, respectively. Based on the offset amount y obtained from a1, determine the positions of the tool entry point x1 of the A end (6) and the tool entry point x2 of the B end (7) of the rod (1), respectively. Ensure that the axis line 1 (401) of the hole 1 (301) and the axis line 2 (402) drilled from the tool entry points x1 and x2 at both ends of the rod (1) with the same drill bit are parallel to the axis line 2 (402), and ensure that the tool exit port (8) of the hole 1 (301) and the tool exit port (8) of the hole 2 (302) coincide and have a common center x. a3. Drilling, including the following steps: 1) Clamp the rod (1) according to the clamping direction (602) at end A as determined by a2, and drill from end A of the rod (1) at the entry point x1 determined by a2; 2) Change direction, clamp the rod (1) according to the clamping direction (702) of the B end determined by a2, and drill from the B end of the rod (1) according to the entry point x2 determined by a2; The offset direction (9) of the drill bit described in a1 during actual drilling and the offset y of the center x of the drill bit's exit port (8) from the axis (5) of the rod are obtained by drilling and measuring a cylindrical rod (1) as the experimental rod (101). The drill bit is vertically positioned, and the rod (1) is vertically clamped to perform vertical drilling.

2. The reversing-pair drilling process for machining hollow shafts with rods to ensure uniform wall thickness according to claim 1, characterized in that, Includes the following steps: b1. Clamp the experimental rod (101) on the machine tool and add a mark on end A of the experimental rod (101) to indicate the clamping direction (602) of end A; b2. Select the center of A end (601) as the entry point x1, and make the drill bit drill into the entry point x1 of the A end face of the experimental rod (101) at the end, and drill out a hole (301) with a length equal to that of hole two (302) as the experimental hole. b3. Use a measuring instrument to measure the orientation and thickness h of the thinnest part of the inner wall of the tool outlet (8) of hole one (301); b4. Determine the offset direction (9) of hole one (301) by measuring the orientation of the thinnest point; set the radius of the experimental rod (101) as r1 and the radius of hole one as r2, and obtain the offset y of the center x of the hole one (301) from the axis (5) of the rod, y=r1-h-r2; based on the axial position of the hole one (301) outlet port (8), and the offset direction and offset y of hole one (301), obtain the specific position of the center x of the outlet port.

3. The reversing-pair drilling process for machining hollow shafts with rods to ensure uniform wall thickness according to claim 2, characterized in that, Make a scale view (102) of the experimental rod (101), at least the entry point x1 and the center of the exit port x are reflected in the scale view (102). Draw a line segment (10) from x1 to x and extend the line segment to the B end face of the experimental rod (101). The intersection of the line segment with the B end face is the entry point x2 of the B end face.

4. The reversing-pair drilling process for ensuring uniform wall thickness in hollow shafts using rods as described in claim 2, characterized in that, The tool entry point x2 is determined directly at the B end of the experimental rod (101) from the center (701) of the B end along the offset direction (9) determined by b4. The tool entry point x2 is located at a distance of 2y from the center (701) of the B end along the offset direction (9).

5. The reversing-pair drilling process for machining hollow shafts with rods to ensure uniform wall thickness according to claim 3, characterized in that, Move the entry point x1 and entry point x2 by a distance y in the opposite direction of the offset direction so that x is located on the axis of the rod (1).

6. The reversing-pair drilling process for machining hollow shafts with rods to ensure uniform wall thickness according to any one of claims 3-5, characterized in that, Mark the tool entry point x1 and tool entry point x2, as well as the clamping direction at end A (602) and clamping direction at end B (702) on the cylindrical rod to be machined (1); or, directly input them into the control system of the intelligent machine tool.

7. The reversing-pair drilling process for machining hollow shafts with rods to ensure uniform wall thickness according to claim 6, characterized in that, The clamping direction at end B (702) is the direction after the end B of the rod (1) is reversed to the end where the drill bit is located, and then rotated 180° around the axis (5) of the rod according to the clamping direction at end A (602).

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