A parameterized harmonic reducer flexspline collet

Abstract

The application discloses a parameterized harmonic reducer flexible gear expander clamp, which comprises an expander and a mandrel, the mandrel is coaxially arranged in the expander, and a flexible gear is arranged on the outer side of the expander; the mandrel and the expander are connected through a plurality of balls; when the mandrel is displaced under the action of an axial force, the balls are rolled in the same direction as the force, the inner diameter of the expander is expanded, and the flexible gear is expanded. The inner contour of the slotted expander and the outer contour of the mandrel are accurately described through a parameterized equation, and the design precision of the clamp is improved; the balls are arranged between the slotted expander and the mandrel, the friction is reduced through the rolling of the balls, and the service life of the clamp is improved; meanwhile, two kinds of balls with different diameters are adopted, the deformation of the slotted expander is different at different axial positions, the damage of the connection between the bottom of the flexible gear cup and the cup body is reduced, and the clamping precision of the clamp is improved.

Description

Technical Field

[0001] This invention relates to a flexible gear expansion sleeve clamp, and more particularly to a parameterized harmonic reducer flexible gear expansion sleeve clamp. Background Technology

[0002] The cup-shaped flexible wheel is one of the core components of a robot joint harmonic reducer. Harmonic reducers are high-reduction-ratio, high-precision reduction devices, thus placing high demands on the machining accuracy and surface quality of the cup-shaped flexible wheel. As a thin-walled part, the cup-shaped flexible wheel requires high-precision fixtures for internal expansion and support during precision turning and gear hobbing.

[0003] Traditional conical expansion sleeve clamps, such as Figure 1 As shown, the movement of the internal conical mandrel causes the external expansion sleeve to tighten. However, the conical expansion sleeve has the following problems: 1. After the conical expansion sleeve clamp tightens, warping occurs at the end face of the expansion sleeve, damaging the connection between the bottom of the flexible wheel cup and the cup body. 2. During operation, sliding friction occurs between the outer surface of the conical expansion sleeve mandrel and the inner surface of the expansion sleeve. After a period of use, wear easily occurs, causing the cone angle to decrease, the clamping accuracy to drop, and the machining accuracy of the flexible wheel to decrease. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to propose a parameterized flexible sleeve clamp for harmonic reducers, which uses parameterized contour description to improve the clamping accuracy and accuracy retention of the sleeve clamp.

[0005] Technical solution: The present invention includes an expansion sleeve and a mandrel. The mandrel is coaxially mounted inside the expansion sleeve, and a flexible wheel is mounted on the outside of the expansion sleeve. The mandrel and the expansion sleeve are connected by multiple balls. When the mandrel is subjected to axial force and causes displacement, it drives the balls to roll in the same direction as the force, thereby expanding the inner diameter of the expansion sleeve and tightening the flexible wheel.

[0006] The expansion sleeve includes a tensioning ring. The outer wall of the tensioning ring is provided with multiple slots spaced apart along its circumference. The inner wall of the tensioning ring between two adjacent slots is provided with multiple grooves, which are distributed at intervals along the axial direction of the tensioning ring.

[0007] The groove includes a first large ball groove and a first small ball groove.

[0008] The mandrel and the tensioning ring have multiple grooves spaced apart on their circumferential surfaces, including a second large ball groove and a second small ball groove. A large ball is provided between the second large ball groove and the first large ball groove, and a small ball is provided between the second small ball groove and the first small ball groove. The rolling of the balls reduces friction and improves the service life of the clamp.

[0009] The inner contour of the expansion sleeve and the outer contour of the mandrel are both continuous parametric equations. The parametric equations accurately describe the inner contour of the slotted expansion sleeve and the outer contour of the mandrel, thereby improving the design accuracy of the fixture.

[0010] The inner contour of the expansion sleeve includes the large circular arc segment AB, the transition straight line segment BC, and the small circular arc segment CD.

[0011] The curve equation of the large circular arc segment AB of the expansion sleeve is:

[0012]

[0013] In the formula, x AB Let y be the x-coordinate of any point on curve AB in the rectangular coordinate system XOY. AB Let be the ordinate of any point on curve AB in a rectangular coordinate system, n be the axial length of the expansion sleeve, and D be the ordinate of the expansion sleeve. R The inner diameter of the cup-shaped flexible wheel;

[0014] The equation of the straight line segment BC of the expansion sleeve transition is:

[0015]

[0016] In the formula, y BC Let x be the ordinate of any point on line BC in the rectangular coordinate system XOY. BC Let x be the x-coordinate of any point on line BC in the rectangular coordinate system XOY;

[0017] The curve equation of the small circular arc segment CD of the expansion sleeve is:

[0018]

[0019] In the formula, x CD Let y be the x-coordinate of any point on curve CD in the rectangular coordinate system XOY. CD Let X be the ordinate of any point on curve CD in the rectangular coordinate system XOY.

[0020] The outer contour of the mandrel includes the left segment EF of the large circular arc of the mandrel, the transition straight line segment FG of the large circular arc of the mandrel, the right segment GH of the large circular arc of the mandrel, the transition straight line segment HI of the circular arc of the mandrel, the left segment IJ of the small circular arc of the mandrel, the transition straight line segment JK of the small circular arc of the mandrel, and the left segment KL of the small circular arc of the mandrel.

[0021] The curve equation of the left segment EF of the great circular arc of the mandrel is:

[0022]

[0023] In the formula, y EF Let x be the ordinate of any point on curve EF in the rectangular coordinate system XOY.EF Let x be the x-coordinate of any point on curve EF in the rectangular coordinate system XOY;

[0024] The equation of the straight line segment FG of the mandrel's large circular arc transition is:

[0025]

[0026] In the formula, y FG Let x be the ordinate of any point on line FG in the rectangular coordinate system XOY. FG Let x be the x-coordinate of any point on line FG in the rectangular coordinate system XOY;

[0027] The curve equation of the right segment GH of the great circular arc of the mandrel is:

[0028]

[0029] In the formula, x GH Let y be the x-coordinate of any point on curve GH in the rectangular coordinate system XOY. GH Let be the ordinate value of any point on curve GH in the rectangular coordinate system XOY;

[0030] The linear equation of the arc transition line segment HI of the mandrel is:

[0031]

[0032] In the formula, y HI Let x be the ordinate of any point on line HI in the rectangular coordinate system XOY. HI Let x be the x-coordinate of any point on line HI in the rectangular coordinate system XOY;

[0033] The curve equation of the left segment IJ of the small circular arc of the mandrel is:

[0034]

[0035] In the formula, y IJ Let x be the ordinate of any point on curve IJ in the rectangular coordinate system XOY. IJ Let x be the x-coordinate of any point on curve IJ in the rectangular coordinate system XOY;

[0036] The equation of the straight line segment JK of the small circular arc transition of the mandrel is:

[0037]

[0038] In the formula, y JK Let x be the ordinate of any point on curve JK in the rectangular coordinate system XOY. JK Let x be the x-coordinate of any point on curve JK in the rectangular coordinate system XOY;

[0039] The curve equation of the left segment KL of the small circular arc of the mandrel is:

[0040]

[0041] In the formula, y KL Let x be the ordinate of any point on curve KL in the rectangular coordinate system XOY. KL Let x be the x-coordinate of any point on curve KL in the rectangular coordinate system XOY.

[0042] One end of the tensioning ring is connected to a flange, and each slot has an opening near the flange. The flange is used to fix the slotted expansion sleeve to the machine tool connector.

[0043] Beneficial effects: This invention accurately describes the inner contour of the slotted expansion sleeve and the outer contour of the mandrel through parameterized equations, thereby improving the design accuracy of the fixture; ball bearings are placed between the slotted expansion sleeve and the mandrel, and the rolling of the ball bearings reduces friction and improves the service life of the fixture; at the same time, two different diameter ball bearings are used, so that the deformation of the slotted expansion sleeve is different at different axial positions, reducing damage at the connection between the bottom of the flexible wheel cup and the cup body, and improving the clamping accuracy of the fixture. Attached Figure Description

[0044] Figure 1 This is a sectional view of a traditional conical expansion sleeve;

[0045] Figure 2 This is a schematic diagram of the overall structure of the present invention;

[0046] Figure 3 yes Figure 2 A sectional view;

[0047] Figure 4 This is a schematic diagram of the cup-shaped flexible wheel of the present invention;

[0048] Figure 5 This is a schematic diagram of the slotted expansion sleeve of the present invention;

[0049] Figure 6 This is a schematic diagram of the mandrel structure of the present invention;

[0050] Figure 7 This is a structural diagram of the parametric slotted expansion sleeve inner contour and mandrel outer contour of the present invention. Detailed Implementation

[0051] The invention will now be further described with reference to the accompanying drawings.

[0052] like Figures 2 to 6 As shown, the present invention includes an expansion sleeve 1, a flexible wheel 2, and a mandrel 3. The mandrel 3 is installed inside the expansion sleeve 1, and the flexible wheel 2 is installed on the outer side. The flexible wheel 2 adopts the following... Figure 4 The cup-shaped flexible wheel shown has its spindle 3 and expansion sleeve 1 coaxially mounted with a coaxiality error of less than 5 micrometers. The spindle 3 and expansion sleeve 1 are connected by multiple ball bearings, including large ball bearings 5 ​​and small ball bearings 4. The rolling of these balls reduces friction and extends the service life of the clamp. The use of two different diameter ball bearings ensures varying deformation at different axial positions of the slotted expansion sleeve, reducing damage at the connection between the flexible wheel's cup bottom and the cup body, and improving the clamping accuracy. When the spindle 3 is subjected to a horizontal leftward axial force and displaces to the left, it causes the ball bearings to roll to the left, thereby expanding the inner diameter of the expansion sleeve 1 and tightening the flexible wheel 2, thus achieving the clamping purpose.

[0053] like Figure 5 As shown, the expansion sleeve 1 is a slotted expansion sleeve, including a tensioning ring 14. Multiple slots 13 are evenly spaced along the circumference of the outer wall of the tensioning ring 14. Each slot 13 is distributed along the axial direction of the tensioning ring 14. One end of the tensioning ring 14 is connected to a flange 11. Each slot 13 has an opening 12 near the flange 11. The flange 11 is used to fix the slotted expansion sleeve to the machine tool connector. Multiple grooves are formed on the inner wall of the tensioning ring 14 between adjacent slots 13. These grooves are spaced along the axial direction of the tensioning ring 14, including a first large ball groove 15 and a first small ball groove 16. The inner contour of the expansion sleeve 1 is a continuous parametric equation.

[0054] like Figure 6 As shown, the circumferential surface of the mandrel 3 that mates with the tensioning ring 14 is provided with multiple grooves at even intervals, including a second large ball groove 32 and a second small ball groove 33. The second large ball groove 32 mates with the first large ball groove 15 of the tensioning ring 14, and the second small ball groove 33 mates with the first small ball groove 16 of the tensioning ring 14. A large ball 5 is provided between the second large ball groove 32 and the first large ball groove 15, and a small ball 4 is provided between the second small ball groove 33 and the first small ball groove 16. The mandrel 3 also includes a tensioning shaft 31 and a ejector shaft 34. The tensioning shaft 31 has external threads for connecting to the machine tool drawbar to achieve axial displacement; the ejector shaft 34 has a tapered hole on its end face for connecting to the machine tool spindle ejector. To achieve rotational accuracy, the tensioning shaft 31 and the ejector shaft 34 are coaxially mounted, with a coaxiality within 5 micrometers. The outer contour of the mandrel 3 is a continuous parametric equation.

[0055] like Figure 7 As shown, a rectangular coordinate system XOY is established with the central axis of the expansion sleeve 1 and the mandrel 3 as the horizontal axis and the flange end face of the expansion sleeve 1 as the vertical axis, which is used to describe the inner contour of the expansion sleeve 1 and the outer contour of the mandrel 3.

[0056] The inner contour of the expansion sleeve 1 includes the large circular arc segment AB, the transition straight line segment BC, and the small circular arc segment CD.

[0057] 1) The curve equation of the large circular arc segment AB of the expansion sleeve is:

[0058]

[0059] In the formula, x AB Let y be the x-coordinate of any point on curve AB in the rectangular coordinate system XOY. AB Let be the ordinate of any point on curve AB in a rectangular coordinate system, n be the axial length of the expansion sleeve, and D be the ordinate of the expansion sleeve. R This is the inner diameter of the cup-shaped flexible wheel.

[0060] 2) The equation of the straight line segment BC for the expansion sleeve transition is:

[0061]

[0062] In the formula, y BC Let x be the ordinate of any point on line BC in the rectangular coordinate system XOY. BC Let x be the x-coordinate of any point on line BC in the rectangular coordinate system XOY.

[0063] 3) The curve equation of the small circular arc segment CD of the expansion sleeve is:

[0064]

[0065] In the formula, x CD Let y be the x-coordinate of any point on curve CD in the rectangular coordinate system XOY. CD Let X be the ordinate of any point on curve CD in the rectangular coordinate system XOY.

[0066] The outer contour of the mandrel 3 includes the left segment EF of the large circular arc of the mandrel, the transition straight line segment FG of the large circular arc of the mandrel, the right segment GH of the large circular arc of the mandrel, the transition straight line segment HI of the circular arc of the mandrel, the left segment IJ of the small circular arc of the mandrel, the transition straight line segment JK of the small circular arc of the mandrel, and the left segment KL of the small circular arc of the mandrel.

[0067] 1) The equation of the curve for the left segment EF of the great circle arc of the mandrel is:

[0068]

[0069] In the formula, y EF Let x be the ordinate of any point on curve EF in the rectangular coordinate system XOY. EF Let x be the x-coordinate of any point on curve EF in the rectangular coordinate system XOY.

[0070] 2) The equation of the straight line segment FG, which is the transition line of the great circle arc of the mandrel, is:

[0071]

[0072] In the formula, y FG Let x be the ordinate of any point on line FG in the rectangular coordinate system XOY. FG Let x be the x-coordinate of any point on line FG in the rectangular coordinate system XOY.

[0073] 3) The equation of the curve GH of the right segment of the great circle arc of the mandrel is:

[0074]

[0075] In the formula, x GH Let y be the x-coordinate of any point on curve GH in the rectangular coordinate system XOY. GH Let be the ordinate value of any point on curve GH in the rectangular coordinate system XOY.

[0076] 4) The linear equation of the mandrel's circular arc transition line segment HI is:

[0077]

[0078] In the formula, y HI Let x be the ordinate of any point on line HI in the rectangular coordinate system XOY. HI Let x be the x-coordinate of any point on line HI in the rectangular coordinate system XOY.

[0079] 5) The curve equation of the left segment IJ of the small circular arc of the mandrel is:

[0080]

[0081] In the formula, y IJ Let x be the ordinate of any point on curve IJ in the rectangular coordinate system XOY. IJ Let x be the x-coordinate of any point on curve IJ in the rectangular coordinate system XOY.

[0082] 6) The equation of the straight line segment JK, which is the small circular arc transition line of the mandrel, is:

[0083]

[0084] In the formula, y JK Let x be the ordinate of any point on curve JK in the rectangular coordinate system XOY. JK Let x be the x-coordinate of any point on curve JK in the rectangular coordinate system XOY.

[0085] 7) The curve equation of the left segment KL of the small circular arc of the mandrel is:

[0086]

[0087] In the formula, y KLLet x be the ordinate of any point on curve KL in the rectangular coordinate system XOY. KL Let x be the x-coordinate of any point on curve KL in the rectangular coordinate system XOY.

[0088] The slotted expansion sleeve inner contour and mandrel outer contour formed by the above parametric equations can effectively improve the design accuracy of the expansion sleeve fixture. Furthermore, the application of ball bearings enhances the fixture's accuracy retention. The different diameters of the large and small ball bearings reduce damage at the connection between the flexible wheel cup bottom and the cup body. In addition, the parametric equations describe the process, requiring only the determination of the expansion sleeve's axial length and the cup-shaped flexible wheel's inner diameter to complete the design, providing a theoretical model for the design and testing of similar products.

Claims

1. A parameterized harmonic reducer flexspline expansion sleeve fixture, characterized by, The expansion sleeve and the mandrel, the expansion sleeve is coaxially installed inside the mandrel, the expansion sleeve is installed outside the flexible gear, the mandrel and the expansion sleeve are connected through a plurality of balls, when the mandrel is displaced by the axial force, the balls are rolled in the same direction, the inner diameter of the expansion sleeve is expanded, and the flexible gear is expanded, the expansion sleeve comprises a tightening ring, a plurality of slotted openings are formed on the outer wall of the tightening ring along the circumference, a plurality of grooves are formed on the inner wall of the tightening ring between the adjacent two slotted openings, the plurality of grooves are distributed along the axial direction of the tightening ring, the grooves comprise first large ball grooves and first small ball grooves, a plurality of grooves are formed on the circumference of the mandrel and the tightening ring, the grooves comprise second large ball grooves and second small ball grooves, the large balls are arranged between the first large ball grooves and the second large ball grooves, and the small balls are arranged between the first small ball grooves and the second small ball grooves.

2. A parameterized harmonic reducer flexspline collet according to claim 1, wherein, The inner contour of the expansion sleeve and the outer contour of the mandrel are both continuous parametric equations.

3. A parameterized harmonic reducer flexspline collet according to claim 1 or 2, wherein, The inner contour of the expansion sleeve comprises an expansion sleeve large circular arc segment AB, an expansion sleeve transition straight line segment BC and an expansion sleeve small circular arc segment CD.

4. A parameterized harmonic reducer flexspline expander clamp according to claim 3, wherein, The curve equation of the expansion sleeve large circular arc segment AB is: In the formula, Let any point on curve AB be in a rectangular coordinate system The x-coordinate value in the middle, Let be the ordinate of any point on curve AB in a rectangular coordinate system, n be the axial length of the expansion sleeve, and D be the ordinate of the expansion sleeve. R The inner diameter of the cup-shaped flexible wheel; The straight line equation of the expansion sleeve transition straight line segment BC is: In the formula, is the vertical coordinate value of any point on the straight line BC in the rectangular coordinate system , is the horizontal coordinate value of any point on the straight line BC in the rectangular coordinate system . The curve equation of the expansion sleeve small circular arc segment CD is: In the formula, is the horizontal coordinate value of any point on the curve CD in the rectangular coordinate system , is the vertical coordinate value of any point on the curve CD in the rectangular coordinate system .

5. A parameterized harmonic reducer flexspline collet according to claim 1 or 2, wherein, The outer contour of the mandrel comprises a mandrel large circular arc left segment EF, a mandrel large circular arc transition straight line segment FG, a mandrel large circular arc right segment GH, a mandrel circular arc transition straight line segment HI, a mandrel small circular arc left segment IJ, a mandrel small circular arc transition straight line segment JK and a mandrel small circular arc left segment KL.

6. A parameterized harmonic reducer flexspline collet according to claim 5, wherein, The curve equation of the mandrel large circular arc left segment EF is: In the formula, is the ordinate value of any point on the curve EF in the rectangular coordinate system , is the abscissa value of any point on the curve EF in the rectangular coordinate system . The straight line equation of the mandrel large circular arc transition straight line segment FG is: In the formula, is the longitudinal coordinate value of any point on the straight line FG in the rectangular coordinate system , is the transverse coordinate value of any point on the straight line FG in the rectangular coordinate system . The curve equation of the mandrel large circular arc right segment GH is: In the formula, is the horizontal coordinate value of any point on the curve GH in the rectangular coordinate system , is the vertical coordinate value of any point on the curve GH in the rectangular coordinate system . The straight line equation of the mandrel circular arc transition straight line segment HI is: wherein is the ordinate value of any point on the straight line HI in the rectangular coordinate system , is the abscissa value of any point on the straight line HI in the rectangular coordinate system . The curve equation of the mandrel small circular arc left segment IJ is: In the formula, is the ordinate value of any point on the curve IJ in the rectangular coordinate system , is the abscissa value of any point on the curve IJ in the rectangular coordinate system . The straight line equation of the mandrel small circular arc transition straight line segment JK is: In the formula, is the vertical coordinate value of any point on the curve JK in the rectangular coordinate system , is the horizontal coordinate value of any point on the curve JK in the rectangular coordinate system . The curve equation of the mandrel small circular arc left segment KL is: In the formula, is the longitudinal coordinate value of any point on the curve KL in the rectangular coordinate system , is the transverse coordinate value of any point on the curve KL in the rectangular coordinate system .

7. A parameterized harmonic reducer flexspline expander clamp according to claim 1, wherein, One end of the tightening ring is connected with a flange, and each slotted opening is provided with an opening near one end of the flange.

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