An end-face hole machining self-centering clamping fixture and fixture assembly

Abstract

The present invention discloses a self - centering clamping fixture and a fixture assembly for machining holes on the end face of a shaft, including a circumferential limiting component, which is adapted to define the position of the central axis of the workpiece; a clamping component, which is adapted to axially fix the workpiece, and the clamping component has a horizontal limiting surface. When the clamping component clamps the workpiece, the horizontal positioning surface of the workpiece fits with the horizontal limiting surface. The present invention uses the clamping component to restrict four degrees of freedom of the workpiece, and the horizontal limiting surface of the clamping component restricts three degrees of freedom of the workpiece. The precise positioning of the workpiece is achieved by over - positioning, with extremely high positioning accuracy, which can fully meet the accuracy requirements of the output shaft of the cycloid pinwheel speed reducer. Moreover, only one clamping is required to meet the high - precision requirements, improving the processing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of machining, and particularly to a self-centering clamping fixture and a fixture assembly for machining holes on the end face of a shaft, and specifically to a self-centering clamping fixture for machining holes on the end face of the output shaft of a cycloid pinwheel speed reducer. Background Art

[0002] The accuracy of the holes on the end face of the output shaft of a cycloid pinwheel speed reducer (hereinafter referred to as the workpiece) affects the transmission power and efficiency of the cycloid pinwheel speed reducer. The higher the accuracy of the holes on the end face and the positional accuracy of the distributed holes, for the same type of speed reducer with the same input power, the output power and torque are greater.

[0003] Due to the high accuracy requirements of this workpiece, the positioning accuracy of ordinary fixtures is low and the clamping efficiency is low, and it is difficult to meet the accuracy requirements with a single clamping and machining. Therefore, the original machining method generally uses a vertical drill to drill holes first and then a boring machine to finish boring the holes. This method requires multiple machine tools and multiple positioning and clamping of the workpiece, which has a great impact on the machining accuracy and low efficiency. Summary of the Invention

[0004] In order to solve the technical problems in the prior art that there is no special fixture suitable for the output shaft of a cycloid pinwheel speed reducer, and when machining the holes on its end face, multiple machine tools and multiple positioning and clamping of the workpiece are required, resulting in low machining accuracy and low efficiency, the present invention provides a self-centering clamping fixture and a fixture assembly for machining holes on the end face of a shaft to solve the above problems.

[0005] The present invention provides a self-centering clamping fixture for machining holes on the end face of a shaft, including a circumferential limiting component, which is adapted to define the position of the central axis of the workpiece; a clamping component, which is adapted to axially fix the workpiece, and the clamping component has a horizontal limiting surface. When the clamping component clamps the workpiece, the horizontal positioning surface of the workpiece fits with the horizontal limiting surface; the horizontal limiting surface corresponds to the surface of the clamping component perpendicular to the central axis of the workpiece.

[0006] The circumferential limiting component performs circumferential pre-positioning on the workpiece and simultaneously restricts four degrees of freedom of the workpiece: linear displacement in two coordinate axis directions perpendicular to the central axis of the workpiece and rotation around two coordinate axes perpendicular to the central axis of the workpiece. The horizontal limiting surface of the clamping component can restrict three degrees of freedom of the workpiece: linear displacement in the direction of the central axis of the workpiece and rotation around two coordinate axes perpendicular to the central axis of the workpiece. An over-positioning form (exceeding the limitation of six degrees of freedom) is adopted to ensure the precise positioning of the workpiece, and finally the workpiece is fixed by clamping, restricting the rotation of the workpiece around its central axis. The present invention has extremely high accuracy requirements for the manufacture of the fixture.

[0007] Further, the circumferential limiting component is fixed on the fixture body; the circumferential limiting component has a shaft hole suitable for the workpiece to be inserted; the clamping component includes an elastic positioning sleeve and a claw component located inside the shaft hole, and the horizontal limiting surface is located on the elastic positioning sleeve. When the claw component moves axially away from the elastic positioning sleeve, the claw component contracts and pulls the workpiece, and the elastic positioning sleeve moves into the shaft hole and contracts driven by the workpiece; when the claw component moves axially closer to the elastic positioning sleeve, both the claw component and the elastic positioning sleeve expand to release the workpiece.

[0008] Since the elastic positioning sleeve expands and contracts radially, the center positioning of the workpiece can be ensured to be accurate, and the skew of the workpiece during the clamping process can be avoided.

[0009] Further, the fixture further includes a pull stud for fixing one end of the workpiece away from the end face to be machined, and the claw component is adapted to contract and pull the pull stud.

[0010] Further, one end of the shaft hole close to the end face to be machined has a tapered hole section with an inner diameter gradually increasing from the middle of the circumferential limiting component to the end of the circumferential limiting component, and the elastic positioning sleeve is located in the tapered hole section.

[0011] Further, a plurality of opening grooves are circumferentially arranged at both axial ends of the elastic positioning sleeve. When the elastic positioning sleeve is in an expanded state, the maximum inner diameter of the elastic positioning sleeve is smaller than the outer diameter of the horizontal positioning surface; when the elastic positioning sleeve is tightened, the outer surface of the elastic positioning sleeve is a tapered structure that fits the shaft hole, and the inner surface of the elastic positioning sleeve is a cylindrical structure that fits the workpiece.

[0012] Further, the fixture further includes a power component, which is connected to the claw component and drives the claw component to make a reciprocating movement axially.

[0013] Further, the power component includes an oil cylinder body, a piston, a cylinder head and a connecting rod. The cylinder head is closed at one axial end of the oil cylinder body. The piston makes a reciprocating movement axially in the oil cylinder body. One end of the connecting rod is connected to the piston, and the other end is connected to the claw component.

[0014] The piston divides the oil cylinder body into a rod chamber and a rodless chamber. The rod chamber is connected to the oil tank through a first oil port, and the rodless chamber is connected to the oil tank through a second oil port. When the rod chamber is filled with oil, the claw component pulls the workpiece, and when the rodless chamber is filled with oil, the claw component releases the workpiece.

[0015] Further, the circumferential position-limiting assembly includes a positioning cone sleeve, a positioning sleeve, and a shaft sleeve that are sequentially connected end to end along the axial direction and whose centers are adapted for the workpiece to be inserted. The elastic positioning sleeve is located within the positioning cone sleeve, the claw assembly is located within the shaft sleeve, and the positioning cone sleeve and the shaft sleeve are respectively fixed to the fixture body.

[0016] Further, the claw assembly includes a plurality of claw portions hinged to one end of the connecting rod and arranged circumferentially along the connecting rod. The inner diameter of the shaft sleeve gradually decreases from the end close to the end face to be machined to the end far from the end face to be machined.

[0017] The present invention also provides a fixture assembly, which includes a fixture body and the self-centering clamping fixture for machining the shaft end face hole described above. The upper surface of the fixture body has one or more recessed grooves adapted to place the self-centering clamping fixture for machining the shaft end face hole.

[0018] The present invention also provides a fixture assembly. The fixture body is installed on the workbench. A plurality of T-shaped grooves are arranged in parallel at the top of the workbench. A positioning key adapted to be inserted into the T-shaped groove is fixed to the bottom of the fixture body. The T-shaped screw located within the T-shaped groove fixes the fixture body and the workbench.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) For the self-centering clamping fixture for machining the shaft end face hole of the present invention, the circumferential position-limiting assembly restricts four degrees of freedom of the workpiece, and the horizontal limiting surface of the clamping assembly restricts three degrees of freedom of the workpiece. The over-positioning method is adopted to achieve more accurate positioning of the workpiece, with extremely high positioning accuracy, which can fully meet the accuracy requirements of the output shaft of the cycloid pinwheel reducer. And only one clamping is required to meet the high machining accuracy requirements, greatly improving the machining efficiency.

[0021] (2) In the present invention, the axial tension of the workpiece is realized through the claw assembly and the elastic positioning sleeve. The elastic positioning sleeve contracts radially to clamp the workpiece, which can ensure accurate center positioning of the workpiece and avoid skewing of the workpiece during the clamping process.

[0022] (3) Through the matching of the elastic positioning sleeve that can elastically expand and contract radially with the shaft hole, when the elastic positioning sleeve moves towards the inside of the shaft hole, it gradually contracts radially, and when it moves towards the end of the shaft hole, it gradually expands radially, realizing the rapid clamping of the workpiece.

[0023] (4) In the present invention, the hydraulic-driven power assembly drives the claw assembly to reciprocate. The driving force is large, which can avoid loosening of the fixture. Moreover, a set of unified driving system can simultaneously control multiple fixtures to clamp multiple workpieces, greatly improving the machining efficiency. Description of the Drawings

[0024] The following further illustrates the present invention in conjunction with the drawings and embodiments.

[0025] Figure 1 It is a schematic structural diagram of the output shaft of a cycloid pinwheel speed reducer;

[0026] Figure 2 It is a schematic diagram of the use state of the self-centering clamping fixture for machining the hole on the end face of the shaft according to the present invention;

[0027] Figure 3 It is Figure 2 An enlarged view of the M position in

[0028] Figure 4 It is Figure 2 An enlarged view of the N position in

[0029] Figure 5 It is a schematic structural diagram of the elastic positioning sleeve described in the present invention;

[0030] Figure 6 It is the front view (the internal structure is visible) of the specific implementation manner of the fixture assembly described in the present invention

[0031] Figure 7 It is the top view of the specific implementation manner of the fixture assembly described in the present invention;

[0032] Figure 8 It is a schematic diagram of the assembly relationship between the fixture body and the workbench in the present invention.

[0033] In the figure, 1, workpiece, 101, end face to be machined, 102, maximum shaft section, 103, limiting shaft section, 104, necking section, 105, hole to be machined, 106, horizontal positioning surface, 2, clamping assembly, 201, positioning cone sleeve, 202, positioning sleeve, 203, shaft sleeve, 2031, step, 2032, supporting surface, 3, elastic positioning sleeve, 301, horizontal limiting surface, 302, opening groove, 4, jaw assembly, 401, turned-out part, 5, shaft hole, 501, tapered hole section, 6, fixture body, 601, recessed groove, 602, positioning key, 7, pull stud, 8, chip guard, 9, power assembly, 901, oil cylinder body, 9011, rod chamber, 9012, rodless chamber, 9013, first oil port, 9014, second oil port, 902, piston, 903, cylinder head, 904, connecting rod, 10, T-shaped screw, 11, first pipeline, 12, second pipeline, 13, first oil passage, 14, second oil passage, 15, quick connector, 16, cutting tool, 17, workbench, 1701, T-shaped groove. Specific implementation manner

[0034] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "upper", "lower", "vertical", "horizontal", "inner", "outer", "axial", "radial", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0036] In addition, the terms "first", "second", etc. are only used for descriptive purposes and should not be construed as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0037] As Figure 1 shown is a schematic diagram of the output shaft of a cycloid pinwheel speed reducer. The output shaft of the cycloid pinwheel speed reducer is a stepped shaft structure with a gradually decreasing radial dimension. The end face 101 to be machined is the end face of the shaft section with the largest radial dimension. The plurality of through holes evenly distributed in the circumferential direction on the end face 101 to be machined are the holes 105 to be machined. The shaft section on the workpiece 1 for inserting the workpiece 1 of the present invention is the limiting shaft section 103. The maximum shaft section 102 and the limiting shaft section 103 are transitioned through a necking section 104. The necking section 104 has a horizontal positioning surface 106 protruding from the limiting shaft section 103.

[0038] In the present invention, the direction and positional relationship are based on the position and state of each component in the drilling state. For example, during the drilling process, the horizontal positioning surface 106 is vertically downward, the end face 101 to be machined is the upper surface of the workpiece 1, and the workpiece 1 is inserted into the fixture from top to bottom.

[0039] As Figures 2 - 4 shown, a self-centering clamping fixture for machining holes on the end face of a shaft includes a circumferential limiting component 2 and a clamping component. The circumferential limiting component 2 is adapted to define the position of the central axis of the workpiece 1; the clamping component is adapted to axially fix the workpiece 1, and the clamping component has a horizontal limiting surface 106. When the clamping component clamps the workpiece, the horizontal positioning surface 106 of the workpiece 1 is in contact with the horizontal limiting surface 301; the horizontal limiting surface 301 corresponds to the surface of the clamping component perpendicular to the central axis of the workpiece 1.

[0040] The circumferential positioning component 2 performs a preliminary circumferential positioning of the workpiece 1, limits the workpiece 1 inside the shaft hole 5, and restricts the degrees of freedom of the workpiece 1 in the following four directions: linear displacements in the two coordinate axis directions perpendicular to the central axis of the workpiece 1 and rotations around the two coordinate axes perpendicular to the central axis of the workpiece 1. Taking the central axis of the workpiece 1 as the Z axis, the circumferential positioning component 2 restricts the displacements of the workpiece 1 along the X axis and the Y axis, as well as the rotations around the X axis and the Y axis. The horizontal limiting surface 301 defines the position of the horizontal positioning surface 106 on the workpiece 1, thereby restricting the degrees of freedom of the workpiece 1 in the following three directions: linear displacement along the central axis of the workpiece 1, rotations around the two coordinate axes perpendicular to the central axis of the workpiece 1. In other words, it restricts the displacement of the workpiece 1 along the Z axis, as well as the rotations around the X axis and the Y axis. Finally, the workpiece 1 is clamped through the clamping function of the clamping component, restricting the rotation of the workpiece 1 around the Z axis and fixing the workpiece 1 at the same time.

[0041] Specifically, the circumferential positioning component 2 is fixed on the fixture body 6; the circumferential positioning component 2 has a shaft hole 5 suitable for the insertion of the workpiece 1; the clamping component includes an elastic positioning sleeve 3 and a jaw component 4 located inside the shaft hole 5. The horizontal limiting surface 301 is located on the elastic positioning sleeve 3. When the jaw component 4 moves axially away from the elastic positioning sleeve 3, the jaw component 4 contracts and pulls the workpiece 1, and the elastic positioning sleeve 3 moves and contracts toward the inside of the shaft hole 5 driven by the workpiece 1; when the jaw component 4 moves axially closer to the elastic positioning sleeve 3, both the jaw component 4 and the elastic positioning sleeve 3 expand to release the workpiece 1.

[0042] The jaw component 4 is used to axially tighten the workpiece 1, and the elastic positioning sleeve 3 is used to radially clamp the workpiece 1.

[0043] During the process of clamping the workpiece 1, the central axis of the elastic positioning sleeve 3 always remains unchanged, thereby ensuring that the central axis of the workpiece 1 is in a vertical state when clamped, and avoiding the skew of the workpiece 1 during the clamping process.

[0044] After the jaw component 4 grabs the workpiece 1, it pulls the workpiece 1 downward. In order to avoid damage to the surface of the workpiece 1 by the jaw component 4, in a specific embodiment of the present invention, the fixture further includes a pull stud 7 that fixes one end of the workpiece 1 away from the end face 101 to be machined. The jaw component 4 is suitable for contracting and pulling the pull stud 7. The pull stud 7 is a prior art. The pull stud 7 is also called a blind rivet. One end is a rivet, and the other end is a flat round head end. The rivet is riveted to the central part of the end face of the workpiece 1. The jaw component 4 grabs the flat round head end and pulls the flat round head end downward. The jaw component 4 is mainly used to pull the workpiece 1 downward to axially fix the workpiece 1. Therefore, the clamping force of the jaw component 4 does not need to be very large, as long as it can hold the pull stud 7.

[0045] Elastic positioning sleeve 3:

[0046] In a specific embodiment of the present invention, the elastic positioning sleeve 3 is used to clamp one end of the workpiece 1, and the jaw assembly 4 is used to pull the other end of the workpiece 1. At this time, the elastic positioning sleeve 3 and the jaw assembly 4 are respectively close to both ends of the shaft hole 5, which is convenient for disassembly and assembly. The elastic positioning sleeve 3 and the shaft hole 5 can adopt but are not limited to the following structural cooperation: one end of the shaft hole 5 close to the end face 101 to be machined has a tapered hole section 501 with an inner diameter gradually increasing from the middle of the circumferential limiting component 2 to the end of the circumferential limiting component 2, and the elastic positioning sleeve 3 is located in the tapered hole section 501. The elastic positioning sleeve 3 can radially expand and contract. When the elastic positioning sleeve 3 is in the expanded state, the maximum inner diameter of the elastic positioning sleeve 3 is smaller than the outer diameter of the horizontal positioning surface 106. That is, when the workpiece 1 gradually moves downward, the workpiece 1 can drive the elastic positioning sleeve 3 to move downward. When the elastic positioning sleeve 3 is tightened, the outer surface of the elastic positioning sleeve 3 is a tapered structure that fits with the shaft hole 5, and the inner surface of the elastic positioning sleeve 3 is a cylindrical structure that fits with the workpiece 1. That is to say, when the elastic positioning sleeve 3 is in the tightened state, the outer diameter dimension of the elastic positioning sleeve 3 is consistent with the inner diameter dimension of the tapered hole section 501 of the shaft hole 5, approximately a trumpet-shaped structure, and the inner diameter dimension of the elastic positioning sleeve 3 is consistent with the inner diameter dimension of the workpiece 1. The elastic positioning sleeve 3 is mainly used to clamp the first shaft section connected below the necking section 104. Therefore, the inner diameter of the elastic positioning sleeve 3 only needs to be consistent with the radial dimension of the first shaft section, and there is no need to be set as a stepped structure. The radial expansion and contraction of the elastic positioning sleeve 3 can be realized by the following structure: a plurality of opening grooves 302 are circumferentially arranged at both axial ends of the elastic positioning sleeve 3. As Figure 5 shown, the opening grooves 302 extend from the ends of the elastic positioning sleeve 3 towards the middle, and the opening grooves 302 at both ends of the elastic positioning sleeve 3 are arranged staggeredly. Preferably, an anti-chip sleeve 8 is provided on the circumferential connection seam between the elastic positioning sleeve 3 close to the end face 101 to be machined and the circumferential limiting component 2. As Figure 3 shown, an anti-chip sleeve 8 is provided at the inner and outer diameter junction of the upper surface of the elastic positioning sleeve 3 and the upper surface of the circumferential limiting component 2 to prevent metal chips from entering the gap between the elastic positioning sleeve 3 and the circumferential limiting component 2 during drilling, causing the elastic positioning sleeve 3 to deform and affecting the drilling accuracy of the workpiece 1.

[0047] Power assembly 9:

[0048] The jaw assembly 4 is a fixture commonly used in the machining field. The jaw assembly 4 moves axially under the action of an external force and undergoes radial expansion and contraction during the axial movement. To improve the automation level of the present invention, in another specific embodiment of the present invention, the fixture further includes a power assembly 9. The power assembly 9 is connected to the jaw assembly 4 and drives the jaw assembly 4 to perform reciprocating axial movement. The power assembly 9 can be a cylinder, a mechanical push rod, an oil cylinder, etc. Compared with a cylinder, a hydraulic oil cylinder can provide greater power, can adapt to a more integrated fixture system, and has a wider application range. While the mechanical push rod structure occupies a large space, has a complex structure, and the transmission structure is prone to failure. Therefore, the present invention preferably uses a hydraulic oil cylinder as the power assembly 9. The specific structure is as follows: The power assembly 9 includes an oil cylinder body 901, a piston 902, a cylinder head 903, and a connecting rod 904. The cylinder head 903 is closed at one axial end of the oil cylinder body 901. The piston 902 moves reciprocally axially in the oil cylinder body 901. One end of the connecting rod 904 is connected to the piston 902, and the other end is connected to the jaw assembly 4. When the circumferential limiting assembly 2 is inserted into the center of the oil cylinder body 901, the lower end of the circumferential limiting assembly 2 is fixed to the cylinder head 903. The oil cylinder body 901 and the cylinder head 903 enclose a closed cavity. The piston 902 performs axial reciprocating movement in this cavity. The connecting rod 904 extends into the shaft hole 5 and is connected to the jaw assembly 4.

[0049] The piston 902 divides the oil cylinder body 901 into a rod chamber 9011 and a rodless chamber 9012. The rod chamber 9011 is connected to the fuel tank through a first oil port 9013, and the rodless chamber 9012 is connected to the fuel tank through a second oil port 9014. When the rod chamber 9011 is filled with oil, the jaw assembly 4 grabs and pulls the workpiece 1 downward. When the rodless chamber 9012 is filled with oil, the jaw assembly 4 jacks up and releases the workpiece 1. As Figure 4 described, the middle part of the piston 902 fits with the inner surface of the oil cylinder body 901, dividing the oil cylinder body 901 into a rod chamber 9011 located above and a rodless chamber 9012 located below. The center of the piston 902 allows the circumferential limiting assembly 2 to pass through, avoiding the piston 902 squeezing the circumferential limiting assembly 2 during movement.

[0050] Circumferential limiting assembly 2:

[0051] The circumferential limiting assembly 2 can be an integral structure. Since the workpiece 1 is a stepped shaft, when the circumferential limiting assembly 2 is integrally formed, the shaft hole 5 is also a stepped hole integrally made. This type of hole is very difficult to machine. Therefore, the present invention sets the circumferential limiting assembly 2 as a split structure. Specifically, as Figures 2 - 4 、 Figure 6As shown in the figure, the circumferential limiting component 2 includes a positioning cone sleeve 201, a positioning sleeve 202, and a shaft sleeve 203 that are sequentially connected end to end along the axial direction and whose centers are adapted for the workpiece 1 to be inserted. The elastic positioning sleeve 3 is located inside the positioning cone sleeve 201, and the jaw assembly 4 is located inside the shaft sleeve 203. The positioning cone sleeve 201 and the shaft sleeve 203 are respectively fixed to the fixture body 6. During installation, the shaft sleeve 203, the positioning sleeve 202, and the positioning cone sleeve 201 are sequentially placed into the fixture body 6. The shaft sleeve 203 is fixed to the cylinder head 903. The positioning cone sleeve 201 axially presses the shaft sleeve 203 and the positioning sleeve 202. Alternatively, a step 2031 that engages with the fixture body 6 can be provided on the outer surface of the shaft sleeve 203. When the positioning cone sleeve 201 is fixed, the step 2031 of the shaft sleeve 203 abuts against the fixture body 6. Finally, the shaft sleeve 203 and the cylinder head 903 are fixed by screws, achieving a double fixation effect. The positioning sleeve 202 can be provided with one or multiple sleeves, depending on the stepped levels of the outer diameter of the workpiece 1. If the outer diameter dimension of the workpiece 1 varies significantly, multiple positioning sleeves 202 can be provided. The inner diameter dimensions of each positioning sleeve 202 are different and are respectively sleeved on different shaft segments of the workpiece 1.

[0052] Jaw assembly 4:

[0053] As Figure 3 shown in the figure, the jaw assembly 4 includes multiple claw parts that are hinged to one end of the connecting rod 904 and arranged circumferentially along the connecting rod 904. The inner diameter of the shaft sleeve 203 gradually decreases from the end close to the end face 101 to be machined to the end far from the end face 101 to be machined. That is to say, the lower end of the jaw assembly 4 is the fixed end, and the upper end is the free end. When the jaw assembly 4 is pulled downward, under the restriction of the shaft sleeve 203, the claw parts gradually close until they hook the pull stud 7 and drive the pull stud 7 to move downward. Figure 3 In the figure, the contraction and expansion states of the jaw assembly 4 are respectively indicated by dashed lines. On the left side of the dashed line is the state where the jaw assembly 4 releases the pull stud 7, and on the right side of the dashed line is the state where the jaw assembly 4 clamps the pull stud 7. Preferably, the free end of the jaw assembly 4 has an outwardly extending everted portion 401 in the radial direction. The inner surface of the shaft sleeve 203 has a support surface 2032 facing the elastic positioning sleeve 3. When the jaw assembly 4 is in the expanded state, the everted portion 401 is located above the support surface 303, and the end of the everted portion 401 abuts against the inner side wall above the support surface 2032. When the jaw assembly 4 is pulled downward, the everted portion 401 disengages from the support surface 2032, and the end of the everted portion 401 abuts against the inner side wall below the support surface 2032. Therefore, the radial dimension of the everted portion 401 can change rapidly, and it can quickly clamp the workpiece 1 or the pull stud 7, and the axial dimension of the shaft sleeve 203 can be shortened.

[0054] A fixture assembly includes a fixture body 6 and the above-mentioned self-centering clamping fixture for machining the shaft end face hole. The upper surface of the fixture body 6 has one or more recessed grooves 601 adapted for placing the self-centering clamping fixture for machining the shaft end face hole. AsFigure 2 , Figure 6 and Figure 8 As shown in Figure 2 , Figure 6 and Figure 8 , a plurality of recessed grooves 601 are arranged in an array on the top of the fixture body 6 of the workbench 17. A fixture is placed in each recessed groove 601. After the fixture clamps the workpiece 1, the same tool 16 can be used to drill a plurality of workpieces 1, greatly improving the drilling efficiency.

[0055] The fixture body 6 is usually installed on the workbench 17. A plurality of T-shaped grooves 1701 are arranged in parallel on the top of the workbench 17. A positioning key 602 adapted to be inserted into the T-shaped groove 1701 is fixed at the bottom of the fixture body 6. After positioning, the fixture body 6 and the workbench 17 are fixed by using a T-shaped screw 10. The size of the T-shaped groove 1701 is usually larger than the size of the positioning key 602. If only one positioning key 602 is provided, the fixture body 6 can still rotate within a certain angle in the horizontal plane. If the number of positioning keys 602 is too large, over-positioning will occur. Therefore, two positioning keys 602 are preferably provided.

[0056] In a specific embodiment of the present invention, the above hydraulic cylinder is used as the power for the axial movement of the jaw assembly 4. As shown in Figure 2 and Figures 6 - 8 , the fixture assembly includes a fixture body 6, the above-mentioned self-centering clamping fixture for machining the shaft end face hole, a first pipeline 11 connecting the oil tank and a plurality of first oil ports 9013, and a second pipeline 12 connecting the oil tank and a second oil port 9014. The upper surface of the fixture body 6 has one or more recessed grooves 601 adapted to place the self-centering clamping fixture for machining the shaft end face hole. The side surface of the fixture body 6 has a first oil passage 13 communicating with the first oil port 9013 and a second oil passage 14 communicating with the second oil port 9014. The first oil passage 13 and the second oil passage 14 are respectively connected to the first pipeline 11 and the second pipeline 12 through quick connectors 15. In this embodiment, through the integrated setting, a plurality of fixtures are controlled by a set of common hydraulic system, and synchronous operation of multiple fixtures can be realized.

[0057] In this specification, the schematic description of the terms does not necessarily refer to the same embodiment. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments.

[0058] Based on the above enlightenment of the ideal embodiment of the present invention, through the above description, relevant staff can completely make various changes and modifications within the scope not deviating from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.​​​​

Claims

1. A self-centering clamping fixture for machining holes on the end face of a shaft, characterized in that, Comprising: A circumferential limiting component (2), the circumferential limiting component (2) being adapted to define the position of the central axis of the workpiece (1); A clamping component, the clamping component being adapted to axially fix the workpiece (1), the clamping component having a horizontal limiting surface (301), when the clamping component clamps the workpiece (1), the horizontal positioning surface (106) of the workpiece (1) abuts against the horizontal limiting surface (301); the horizontal limiting surface (301) corresponds to the surface of the clamping component perpendicular to the central axis of the workpiece (1); the circumferential limiting component (2) is fixed on the fixture body (6); the circumferential limiting component (2) has a shaft hole (5) adapted for the workpiece (1) to be inserted; The clamping component includes an elastic positioning sleeve (3) and a claw component (4) located inside the shaft hole (5), the horizontal limiting surface (301) is located on the elastic positioning sleeve (3), when the claw component (4) moves axially away from the elastic positioning sleeve (3), the claw component (4) contracts and pulls the workpiece (1), and the elastic positioning sleeve (3) moves into the shaft hole (5) and contracts under the drive of the workpiece (1); when the claw component (4) moves axially closer to the elastic positioning sleeve (3), both the claw component (4) and the elastic positioning sleeve (3) expand to release the workpiece (1); the fixture further includes a pull stud (7) fixed to one end of the workpiece (1) away from the end face to be machined (101), and the claw component (4) is adapted to contract and pull the pull stud (7); the circumferential limiting component (2) includes a positioning cone sleeve (201), a positioning sleeve (202) and a shaft sleeve (203) that are axially connected end to end in sequence and whose centers are adapted for the workpiece (1) to be inserted, the elastic positioning sleeve (3) is located inside the positioning cone sleeve (201), the claw component (4) is located inside the shaft sleeve (203), and the positioning cone sleeve (201) and the shaft sleeve (203) are respectively fixed to the fixture body (6).

2. The self - centering clamping fixture for machining the hole on the shaft end face according to claim 1, wherein: A plurality of opening grooves (302) are circumferentially arranged at both axial ends of the elastic positioning sleeve (3), when the elastic positioning sleeve (3) is in an expanded state, the maximum inner diameter of the elastic positioning sleeve (3) is smaller than the outer diameter of the horizontal positioning surface (106); when the elastic positioning sleeve (3) is tightened, the outer surface of the elastic positioning sleeve (3) is a conical structure that mates with the shaft hole (5), and the inner surface of the elastic positioning sleeve (3) is a cylindrical structure that mates with the workpiece (1).

3. The self-centering clamping fixture for machining the hole on the end face of the shaft according to claim 1, wherein: The fixture further includes a power component (9), the power component (9) is connected to the claw component (4) and drives the claw component (4) to make a reciprocating axial movement.

4. The self-centering clamping fixture for machining the hole on the end face of the shaft according to claim 3, characterized in that: The power component (9) includes an oil cylinder body (901), a piston (902), a cylinder head (903) and a connecting rod (904), the cylinder head (903) is closed at one axial end of the oil cylinder body (901), the piston (902) makes a reciprocating axial movement in the oil cylinder body (901), one end of the connecting rod (904) is connected to the piston (902), and the other end is connected to the claw component (4); The piston (902) divides the cylinder block (901) into a rod chamber (9011) and a rodless chamber (9012). The rod chamber (9011) is connected to the oil tank through a first oil port (9013), and the rodless chamber (9012) is connected to the oil tank through a second oil port (9014). When the rod chamber (9011) is filled with oil, the jaw assembly (4) pulls the workpiece (1), and when the rodless chamber (9012) is filled with oil, the jaw assembly (4) releases the workpiece (1).

5. The self-centering clamping fixture for machining the hole on the shaft end face according to claim 4, wherein: The jaw assembly (4) includes a plurality of jaw parts hinged to one end of the connecting rod (904) and arranged circumferentially along the connecting rod (904). The inner diameter of the bushing (203) gradually decreases from the end close to the end face to be machined (101) to the end far from the end face to be machined (101). When the jaw assembly (4) is pulled downward, under the restriction of the bushing (203), the jaw parts gradually close until they hook the workpiece. When the jaw assembly (4) is in an expanded state, the jaw parts can release the workpiece.

6. A fixture assembly, characterized in that: It includes a chuck body (6) and the self-centering clamping fixture for machining the shaft end face hole according to any one of claims 1-5. The upper surface of the chuck body (6) has one or more recessed grooves (601) suitable for placing the self-centering clamping fixture for machining the shaft end face hole.

7. The fixture assembly according to claim 6, wherein: The chuck body (6) is installed on the workbench (17). A plurality of T-shaped grooves (1701) are arranged in parallel at the top of the workbench (17). A positioning key (602) suitable for inserting into the T-shaped groove (1701) is fixed at the bottom of the chuck body (6). A T-shaped screw (10) located in the T-shaped groove (1701) fixes the chuck body (6) and the workbench (17).

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