Parameterized harmonic reducer flexspline expansion sleeve fixture

Abstract

The present invention discloses a parameterized harmonic reducer flexspline expansion sleeve jig, comprising an expansion sleeve and a mandrel, the mandrel is coaxially mounted inside the expansion sleeve, the flexspline is mounted outside the expansion sleeve, the mandrel and the expansion sleeve are connected through a number of balls, when the mandrel is displaced under the action of an axial force, the balls are driven to roll in the same direction as the force is received, the inner diameter of the expansion sleeve is expanded, and the flexspline is tensioned. The present invention accurately describes the inner contour of the grooved expansion sleeve and the outer contour of the mandrel by a parameterized equation, improving the precision of the jig design, and the balls are disposed between the grooved expansion sleeve and the mandrel, reducing friction due to the rolling of the balls, and extending the service life of the jig, and employing two different diameter balls, which cause different deformations at different axial positions of the grooved expansion sleeve, reducing damage to the connection between the cup bottom and the cup body of the flexspline, and improving the clamping precision of the jig.

Description

[Technical field]

[0001] The present invention relates to an expansion sleeve fixture for a flexspline, and more particularly to an expansion sleeve fixture for a parameterized harmonic reducer flexspline. [Background technology]

[0002] The cup-shaped flexspline is one of the core components of the harmonic reducer for the joint of a robot, and since the harmonic reducer is a device with a large reduction ratio and high transmission accuracy, the cup-shaped flexspline requires high processing accuracy and surface quality. The cup-shaped flexspline is a thin-walled part, and requires tensioning and support from the inside by a high-precision fixture during the precision finishing and gear cutting process.

[0003] As shown in FIG. 1, the conventional conical expansion sleeve jig drives the external expansion sleeve to be tensioned by the movement of the internal conical mandrel. However, the conical expansion sleeve has the following problems. First, after the conical expansion sleeve jig is tensioned, a warp is formed on the end surface of the existing expansion sleeve, which damages the connection between the cup bottom of the flexspline and the cup body. In addition, during operation, friction is formed between the outer surface of the mandrel of the conical expansion sleeve and the inner surface of the expansion sleeve, which is prone to wear after a certain period of time, the taper angle is reduced, the clamping accuracy is reduced, and the processing accuracy of the flexspline is reduced. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a parameterized expansion sleeve jig for a flexspline of a harmonic reducer that employs a parameterized contour description to improve the clamping accuracy and maintainability of the expansion sleeve jig. [Means for solving the problem]

[0005] The technical solution is as follows: the present invention includes an expansion sleeve and a mandrel, the mandrel is coaxially mounted inside the expansion sleeve, a flexspline is mounted on the outside of the expansion sleeve, and the mandrel and the expansion sleeve are connected through a number of balls, and when the mandrel is displaced under the action of an axial force, the balls are driven to roll in the same direction as the force is received, thereby expanding the inner diameter of the expansion sleeve and tensioning the flexspline.

[0006] The expansion sleeve includes a tension ring having an outer wall with a plurality of open grooves spaced apart along its circumferential direction, and the inner wall of the tension ring between each pair of adjacent open grooves is provided with a plurality of recessed grooves spaced apart along the axial direction of the tension ring.

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

[0008] A plurality of grooves, including a second large ball groove and a second small ball groove, are spaced apart on a circumferential surface of the mandrel that is fitted to the tensioning ring, with a large ball being provided between the second large ball groove and the first large ball groove, and a small ball being provided between the second small ball groove and the first small ball groove, thereby reducing friction through the rolling of the balls and extending the service life of the jig.

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

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

[0011] The large arc portion AB of the expansion sleeve has a curve equation as follows:

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[0012] The outer contour of the mandrel includes a large arc left portion EF of the mandrel, a large arc transition straight portion FG of the mandrel, a large arc right portion GH of the mandrel, an arc transition straight portion HI of the mandrel, a small arc left portion IJ of the mandrel, a small arc transition straight portion JK of the mandrel, and a small arc left portion KL of the mandrel.

[0013] The curve equation of the left great arc portion EF of the mandrel is as follows:

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[0014] A flange is connected to one end of the tension ring, and an opening is provided at one end of each of the opening grooves close to the flange, and the flange is used to fix a slotted expansion sleeve to a connector of a machine tool. Effect of the Invention

[0015] The beneficial effects of the present invention are as follows: the present invention uses parameterized equations to accurately describe the inner contour of the grooved expansion sleeve and the outer contour of the mandrel, improving the precision of the jig design, and disposing balls between the grooved expansion sleeve and the mandrel to reduce friction through ball rolling and extend the service life of the jig; and using balls with two different diameters to cause different deformations at different axial positions of the grooved expansion sleeve, reducing damage to the connection between the cup bottom of the flexspline and the cup body, and improving the clamping precision of the jig. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of a conventional cone-shaped expansion sleeve. [Diagram 2] FIG. 1 is a schematic diagram of the overall structure of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view of FIG. 2. [Figure 4] FIG. 2 is a schematic diagram of the cup-shaped flexspline of the present invention. [Diagram 5] FIG. 2 is a structural schematic diagram of the grooved expansion sleeve of the present invention; [Figure 6] FIG. 2 is a structural schematic diagram of a mandrel of the present invention. [Figure 7] FIG. 2 is a structural diagram of the parameterized inner profile of a grooved expansion sleeve and the outer profile of a mandrel of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The invention will now be further described in conjunction with the drawings.

[0018] As shown in Figures 2 to 6, the present invention includes an expansion sleeve 1, a flexspline 2, and a mandrel 3, the mandrel 3 is attached inside the expansion sleeve 1, and the flexspline 2 is attached outside. The flexspline 2 adopts a cup-shaped flexspline as shown in Figure 4, the mandrel 3 is coaxially attached to the expansion sleeve 1, and the error of coaxiality is less than 5 μm. The mandrel 3 and the expansion sleeve 1 are connected through a plurality of balls, the balls including a large ball 5 and a small ball 4, the friction is reduced by the rolling of the balls, the service life of the jig is extended, and two kinds of balls with different diameters are adopted, so that the deformation at different positions in the axial direction of the grooved expansion sleeve is different, the damage to the connection point between the cup bottom of the flexspline and the cup body is reduced, and the accuracy of clamping by the jig is improved. When the mandrel 3 is displaced to the left under the action of a horizontal axial force in the leftward direction, it drives the balls to roll to the left, expanding the inner diameter of the expansion sleeve 1 and tensioning the flexspline 2, thereby achieving the purpose of clamping.

[0019] As shown in Fig. 5, the expansion sleeve 1 adopts a grooved expansion sleeve, and includes a tension ring 14, a plurality of opening grooves 13 are uniformly spaced on the outer wall of the tension ring 14 along its circumferential direction, each opening groove 13 is distributed along the axial direction of the tension ring 14, a flange 11 is connected to one end of the tension ring 14, and each opening groove 13 has an opening 12 at one end close to the flange 11, which is used to fix the grooved expansion sleeve to a connector of a machine tool. A plurality of grooves are formed on the inner wall of the tension ring 14 between two adjacent opening grooves 13, the plurality of grooves are spaced apart along the axial direction of the tension ring 14, and the plurality of grooves include a first large ball groove 15 and a first small ball groove 16, and the inner contour of the expansion sleeve 1 is a continuous parameterized equation.

[0020] As shown in Fig. 6, a plurality of grooves are uniformly spaced on the circumferential surface of the mandrel 3 that is fitted to the tension ring 14, and the plurality of grooves include a second large ball groove 32 and a second small ball groove 33, the second large ball groove 32 being fitted to the first large ball groove 15 of the tension ring 14 in a one-to-one correspondence, and the second small ball groove 33 being fitted to the first small ball groove 16 of the tension ring 14 in a one-to-one correspondence. 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 further includes a tension shaft 31 and a needle shaft 34, and the tension shaft 31 is formed with a male thread that is connected to a tension bar of a machine tool to realize axial displacement, and a taper hole is provided on the end surface of the needle shaft 34 for connection to a needle of a spindle of the machine tool. To achieve the rotational accuracy, the tightening shaft 31 and the needle shaft 34 are mounted coaxially, and the coaxiality is within 5 μm. The outer contour of the mandrel 3 is a continuous parameterized equation.

[0021] As shown in Figure 7, a Cartesian coordinate system XOY is created with the central axis of the expansion sleeve 1 and mandrel 3 as the horizontal axis and the flange end face of the expansion sleeve 1 as the vertical axis, and is used to describe the inner contour of the expansion sleeve 1 and the outer contour of the mandrel 3.

[0022] The inner contour of the expansion sleeve 1 includes a large circular arc portion AB of the expansion sleeve, a transition straight line portion BC of the expansion sleeve, and a small circular arc portion CD of the expansion sleeve.

[0023] 1) The curve equation of the large arc portion AB of the expansion sleeve is as follows:

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[0024] 2) The linear equation of the transition straight section BC of the expansion sleeve is as follows:

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[0025] 3) The small arc portion CD of the expansion sleeve has a curve equation as follows:

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[0026] The outer contour of the mandrel 3 includes a large arc left portion EF of the mandrel, a large arc transition straight portion FG of the mandrel, a large arc right portion GH of the mandrel, an arc transition straight portion HI of the mandrel, a small arc left portion IJ of the mandrel, a small arc transition straight portion JK of the mandrel, and a small arc left portion KL of the mandrel.

[0027] 1) The curve equation of the left great arc EF of the mandrel is as follows:

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[0028] 2) The linear equation of the mandrel's large arc transition straight line section FG is as follows:

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[0029] 3) The curve equation of the right great circular arc GH of the mandrel is as follows:

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[0030] 4) The linear equation of the mandrel's arc transition straight line portion HI is as follows:

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[0031] 5) The curve equation of the small circular arc left part IJ of the mandrel is as follows:

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[0032] 6) The linear equation of the small arc transition straight line portion JK of the mandrel is as follows:

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[0033] 7) The curve equation of the small circular arc left part KL of the mandrel is as follows:

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[0034] The inner contour of the grooved expansion sleeve and the outer contour of the mandrel formed by the above parameterized equations can effectively improve the design precision of the expansion sleeve jig, and the use of balls improves the maintenance of precision of the expansion sleeve jig, and the large and small balls have different diameters, reducing damage to the connection between the cup bottom and the cup body of the flex spline. Furthermore, by describing the parameterized equations, only the axial length of the expansion sleeve and the inner diameter of the cup-shaped flex spline need to be determined for design, providing a theoretical model for the design and inspection of similar products.

Claims

1. 1. A parameterized harmonic reducer flexspline expansion sleeve fixture comprising an expansion sleeve and a mandrel, the mandrel being coaxially attached inside the expansion sleeve, a flexspline being attached to the outside of the expansion sleeve, the mandrel and the expansion sleeve being connected via a plurality of balls, and when the mandrel is displaced by the action of an axial force, the balls are driven to roll in the same direction as the direction in which the force is received, thereby expanding the inner diameter of the expansion sleeve and tensioning the flexspline.

2. The parameterized harmonic reducer flexspline expansion sleeve fixture of claim 1, characterized in that the expansion sleeve includes a tension ring having a plurality of open grooves spaced apart along its circumferential direction on its outer wall, and the inner wall of the tension ring between each two adjacent open grooves is provided with a plurality of recessed grooves spaced apart along the axial direction of the tension ring.

3. 3. The parameterized harmonic reducer flexspline expansion sleeve fixture as claimed in claim 2, wherein the grooves include a first large ball groove and a first small ball groove.

4. 4. The parameterized expansion sleeve jig for a flexspline of a harmonic reducer as claimed in claim 3, characterized in that a plurality of grooves including a second large ball groove and a second small ball groove are spaced apart on a circumferential surface of the mandrel that is fitted to the tension ring, 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.

5. The parameterized expansion sleeve fixture for a flexspline of a harmonic reducer according to claim 1, characterized in that the inner contour of the expansion sleeve and the outer contour of the mandrel are both continuous parameterized equations.

6. The parameterized harmonic reducer flexspline expansion sleeve jig according to claim 1 or 5, characterized in that the inner contour of the expansion sleeve includes a large arc portion AB of the expansion sleeve, a transition straight line portion BC of the expansion sleeve, and a small arc portion CD of the expansion sleeve.

7. The large arc portion AB of the expansion sleeve has a curve equation as follows: ##EQU00021## In the formula, x ＡＢ is the abscissa value of an arbitrary point on the curve AB in the Cartesian coordinate system XOY, and y ＡＢ is the ordinate value in the Cartesian coordinate system of any point on the curve AB, n is the axial length of the expansion sleeve, and D Ｒ is the inner diameter of the cup-shaped flexspline, The transition straight line section BC of the expansion sleeve has a straight line equation as follows: [0022] In the formula, y ＢＣ is the ordinate value of an arbitrary point on the line BC in the Cartesian coordinate system XOY, and x ＢＣ is the abscissa value of an arbitrary point on the line BC in the Cartesian coordinate system XOY, The small circular arc portion CD of the expansion sleeve has a curve equation as follows: [0023] In the formula, x ＣＤ is the abscissa value of an arbitrary point on the curve CD in the Cartesian coordinate system XOY, and y ＣＤ is a ordinate value in a Cartesian coordinate system XOY of an arbitrary point on the curve CD.

8. The expansion sleeve jig of the parameterized harmonic reducer flexspline according to claim 1 or 5, characterized in that the outer contour of the mandrel includes a large arc left portion EF of the mandrel, a large arc transition straight portion FG of the mandrel, a large arc right portion GH of the mandrel, an arc transition straight portion HI of the mandrel, a small arc left portion IJ of the mandrel, a small arc transition straight portion JK of the mandrel, and a small arc left portion KL of the mandrel.

9. The curve equation of the left great arc portion EF of the mandrel is as follows: ##EQU00024## In the formula, y ＥＦ is the ordinate value of an arbitrary point on the curve EF in the Cartesian coordinate system XOY, and x ＥＦ is the abscissa value of any point on the curve EF in the Cartesian coordinate system XOY, The linear equation of the great circular arc transition straight line portion FG of the mandrel is as follows: [0025] In the formula, y ＦＧ is the ordinate value of an arbitrary point on the line FG in the Cartesian coordinate system XOY, and x ＦＧ is the abscissa value of an arbitrary point on the line FG in the Cartesian coordinate system XOY, The curve equation of the right great circular arc portion GH of the mandrel is as follows: [0026] In the formula, x ＧＨ is the abscissa value of an arbitrary point on the curve GH in the Cartesian coordinate system XOY, and y ＧＨ is the ordinate value of an arbitrary point on the curve GH in the Cartesian coordinate system XOY, The arc transition straight line portion HI of the mandrel has a straight line equation as follows: [0027] In the formula, y ＨＩ is the ordinate value of an arbitrary point on the line HI in the Cartesian coordinate system XOY, and x ＨＩ is the abscissa value of an arbitrary point on the line HI in the Cartesian coordinate system XOY, The curve equation of the small circular arc left portion IJ of the mandrel is as follows: [0028] In the formula, y ＩＪ is the ordinate value of an arbitrary point on the curve IJ in the Cartesian coordinate system XOY, and x ＩＪ is the abscissa value of an arbitrary point on the curve IJ in the Cartesian coordinate system XOY, The linear equation of the small arc transition straight line portion JK of the mandrel is as follows: [0029] In the formula, y ＪＫ is the ordinate value of an arbitrary point on the curve JK in the Cartesian coordinate system XOY, and x ＪＫ is the abscissa value of an arbitrary point on the curve JK in the Cartesian coordinate system XOY, The small arc left portion KL of the mandrel, the curve equation of which is as follows: [0030] In the formula, y ＫＬ is the ordinate value of an arbitrary point on the curve KL in the Cartesian coordinate system XOY, and x ＫＬ is an abscissa value in the Cartesian coordinate system XOY of an arbitrary point on the curve KL.

10. The parameterized harmonic reducer flexspline expansion sleeve jig according to claim 2, characterized in that a flange is connected to one end of the tension ring, and an opening is provided at one end of each opening groove close to the flange.

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