Clamp and machine tool

Abstract

The utility model discloses a clamp and a machine tool, and relates to the technical field of clamps. The clamp comprises a supporting assembly and a tensioning assembly, a supporting part of the supporting assembly is used for supporting a workpiece, and a tensioning part of the tensioning assembly protrudes out of the supporting part and penetrates through a center hole of the workpiece. Due to the fact that the multiple protruding parts are arranged on the side wall of the tensioning part and the concave parts are formed among the multiple protruding parts, when the workpiece needs to be clamped, the tensioning part drives the protruding parts to move in the direction away from the central axis of the tensioning part, the protruding parts can abut against the first hole section of the central hole, and the position of the workpiece in the radial direction can be effectively limited. And the concave part and the second hole section of the center hole are arranged at an interval, so that the concave part cannot transmit the pressure generated by the tensioning part to the workpiece, the protruding amplitude of the outer wall of the workpiece can be reduced, and the machining precision of the workpiece is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of clamps, in particular to a clamp and a machine tool. Background Art

[0002] The workpiece needs to be positioned by a fixture before processing. For example, when the cycloidal wheel of the RV reducer is hobbed or ground, a fixture is needed to fix the cycloidal wheel. The cycloidal wheel is provided with a center hole. After the cycloidal wheel is sleeved on the tensioning part of the fixture through the center hole, the outer diameter of the tensioning part can be increased to limit the position of the cycloidal wheel. Since the cycloidal wheel is also provided with multiple through holes, such as special-shaped holes and crankshaft holes, the tensioning part will generate greater pressure when it expands. The pressure is easily transmitted to the outer wall of the cycloidal wheel through the structure between the special-shaped hole and the crankshaft hole, causing the outer wall of the corresponding part of the cycloidal wheel to bulge. After the cycloidal wheel has processed the outer teeth and the fixture is released, the protruding outer wall of the cycloidal wheel will shrink, causing the radial runout of the outer teeth to deteriorate and the pitch error to increase. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems in the prior art. To this end, the present invention provides a clamp that can reduce the amplitude of the protrusion of the outer wall of a workpiece to improve machining accuracy.

[0004] The utility model also provides a machine tool with the clamp.

[0005] According to an embodiment of the first aspect of the present utility model, a clamp is used to clamp a workpiece having a central hole and a plurality of through holes arranged around the central hole, the clamp comprising: a support assembly including a support portion for supporting an end face of the workpiece;

[0006] a tensioning assembly connected to the support assembly, the tensioning assembly comprising a tensioning portion and a plurality of protrusions, the tensioning portion protruding from the support portion along the axial direction of the clamp and capable of being inserted into the center hole, the plurality of protrusions being connected to the sidewalls of the tensioning portion and spaced apart along the circumference of the tensioning portion, with recesses formed between adjacent protrusions;

[0007] In which, the tightening part can drive the convex part to move in the direction close to or away from the hole wall of the center hole. When the tightening part abuts against the hole wall of the center hole, the convex part abuts against the first hole section of the center hole. The first hole section is the hole section of the through hole corresponding to the center hole along the radial direction of the workpiece. The recessed part and the second hole section of the center hole are arranged at intervals. The second hole section is the hole section between two adjacent through holes corresponding to the center hole along the radial direction of the workpiece.

[0008] The clamp according to the embodiment of the utility model has at least the following beneficial effects:

[0009] The support assembly is provided with a support portion for supporting the workpiece, and the tensioning portion of the tensioning assembly protrudes from the support portion and penetrates the center hole of the workpiece. Because the tensioning portion's sidewall is provided with multiple protrusions, with recesses formed between the protrusions, when clamping the workpiece, the tensioning portion drives the protrusions in a direction away from the tensioning portion's central axis, causing the protrusions to abut against the first section of the center hole, effectively limiting the radial position of the workpiece. The recessed portion is spaced from the second section of the center hole, preventing the pressure generated by the tensioning portion from being transmitted to the workpiece. This reduces the extent of the workpiece's outer wall protrusion, thereby improving workpiece machining accuracy.

[0010] According to some embodiments of the present invention, along the radial direction of the clamp, a maximum distance between a side wall of the convex portion and a side wall of the concave portion is H, which satisfies: 5 μm≤H≤1000 μm.

[0011] According to some embodiments of the present invention, the support portion is fixedly connected to a first positioning block, and the first positioning block is used to position and cooperate with one of the through holes of the workpiece.

[0012] According to some embodiments of the present invention, the clamp also includes a ejector pin and an elastic member, the side wall of the first positioning block is provided with a mounting hole, the elastic member is arranged in the mounting hole, one end of the ejector pin is arranged in the mounting hole and connected to the elastic member, and the other end of the ejector pin protrudes from the mounting hole, and the ejector pin can abut against the side wall of the through hole under the elastic force of the elastic member.

[0013] According to some embodiments of the present invention, the support portion is fixedly connected to a second positioning block, and the second positioning block and the first positioning block are spaced apart along the circumference of the tensioning portion. The second positioning block is used to position and cooperate with another through hole of the workpiece.

[0014] According to some embodiments of the present invention, the support assembly further includes a clamping portion, which is located on a side of the tensioning portion away from the support portion and spaced apart from the support portion, and a clamping space for clamping the workpiece is formed between the clamping portion and the support portion.

[0015] According to some embodiments of the present invention, the clamping portion is detachably connected to the tensioning portion.

[0016] According to some embodiments of the present invention, a positioning seat is provided at one end of the tensioning part away from the supporting part, the maximum outer diameter of the positioning seat is smaller than the maximum outer diameter of the tensioning part, a positioning step is formed at one end of the tensioning part facing the positioning seat, the clamping part is provided with a positioning hole, and the clamping part is sleeved on the positioning seat through the positioning hole and abuts against the positioning step.

[0017] According to some embodiments of the present invention, a connecting shaft is provided at one end of the positioning seat away from the tensioning portion, and the clamp further comprises a fastener fixedly connected to the connecting shaft and abutting against the clamping portion.

[0018] According to some embodiments of the present invention, a first abutment portion is provided on the side of the supporting portion facing the clamping portion, and the first abutment portion is arranged along the extension direction of the edge of the supporting portion; a second abutment portion is provided on the side of the clamping portion facing the supporting portion, and the second abutment portion is arranged along the extension direction of the edge of the clamping portion.

[0019] According to some embodiments of the present invention, the tightening part includes a main body and a flexible ring sleeve, a liquid inlet channel is provided in the main body, a liquid storage tank is provided around the outer wall of the main body, the flexible ring sleeve is fixedly connected to the outer wall of the main body and covers the liquid storage tank, a liquid storage space connected to the liquid inlet channel is formed between the flexible ring sleeve and the inner wall of the liquid storage tank, and the outer wall of the flexible ring sleeve is provided with the convex portion and the concave portion.

[0020] According to some embodiments of the present invention, the support portion and the main body are integrally formed, and the inlet of the liquid inlet channel is provided on an outer side wall of the support portion.

[0021] According to some embodiments of the present invention, the support portion is provided with an avoidance hole, the tensioning portion is passed through the avoidance hole and is spaced apart from the hole wall of the avoidance hole, the tensioning portion includes a plurality of fan-shaped portions and a plurality of elastic portions, the plurality of fan-shaped portions are spaced apart along the circumference of the clamp, the elastic portion is provided between adjacent fan-shaped portions, and the plurality of fan-shaped portions and the plurality of elastic portions enclose one end toward the central axis of the clamp to form a tapered hole;

[0022] The fixture further includes a tapered rod, the tapered rod being inserted into the tapered hole, the tapered rod having a tapered surface, the tapered surface abutting against a side wall of the tapered hole, and the tapered rod being used to move the sector portion in a direction away from the central axis;

[0023] The outer wall of the fan-shaped portion is provided with the convex portion, which protrudes from the elastic portion in the radial direction of the tensioning portion, and the concave portion is formed between adjacent convex portions and the outer side wall of the elastic portion.

[0024] According to an embodiment of the second aspect of the present utility model, a clamp is used to clamp a workpiece having a central hole and a plurality of through holes arranged around the central hole, the clamp comprising: a support assembly including a support portion for supporting an end face of the workpiece;

[0025] A tensioning assembly connected to the support assembly, the tensioning assembly comprising a tensioning portion, the tensioning portion protruding from the support portion and capable of being passed through the center hole;

[0026] An annular portion is sleeved on the outer wall of the tensioning portion, wherein the outer wall of the annular portion is provided with a plurality of convex portions, the plurality of convex portions are spaced apart along the circumference of the annular portion, and concave portions are formed between adjacent convex portions;

[0027] In which, the tightening part can drive the convex part to move in the direction close to or away from the hole wall of the center hole. When the annular part abuts against the hole wall of the center hole, the convex part abuts against the first hole segment of the center hole. The first hole segment is the hole segment of the through hole corresponding to the center hole along the radial direction of the workpiece. The recessed part and the second hole segment of the center hole are spaced apart. The second hole segment is the hole segment between two adjacent through holes corresponding to the center hole along the radial direction of the workpiece.

[0028] The clamp according to the embodiment of the utility model has at least the following beneficial effects:

[0029] The support portion of the support assembly is provided to support the workpiece, and the tensioning portion of the tensioning assembly protrudes from the support portion and is inserted into the center hole of the workpiece. Since the tensioning portion is provided with a ring-shaped portion, the outer wall of the ring-shaped portion is provided with multiple protrusions, and recesses are formed between the multiple protrusions. Therefore, when the workpiece needs to be clamped, the tensioning portion drives the protrusion of the ring-shaped portion to move in a direction away from the central axis of the tensioning portion, so that the protrusion and the first hole section of the center hole can abut, which can effectively limit the radial position of the workpiece. The recess is spaced apart from the second hole section of the center hole, so that the recess does not transmit the pressure generated by the tensioning portion to the workpiece, which can reduce the amplitude of the protrusion of the outer wall of the workpiece and improve the processing accuracy of the workpiece. At the same time, when different types of workpieces need to be processed, the corresponding ring-shaped portion can be replaced, which can reduce the manufacturing cost.

[0030] According to some embodiments of the present invention, one of the positioning groove and the positioning protrusion is provided at one end of the ring piece portion facing the support portion, and the other of the positioning groove and the positioning protrusion is provided on one side of the support portion facing the ring piece portion, and the positioning protrusion and the positioning groove are positioned and matched.

[0031] The machine tool according to the embodiment of the third aspect of the present utility model includes the fixture described in the above embodiment.

[0032] The machine tool according to the embodiment of the utility model has at least the following beneficial effects:

[0033] By employing the clamp of the first embodiment, the clamp supports a workpiece by providing a support portion of the support assembly, and the tensioning portion of the tensioning assembly protrudes from the support portion and penetrates the center hole of the workpiece. Because the tensioning portion's sidewalls are provided with multiple protrusions, with recesses formed between the protrusions, when the workpiece is clamped, the tensioning portion drives the protrusions in a direction away from the tensioning portion's central axis, enabling the protrusions to abut against the first section of the center hole, effectively limiting the radial position of the workpiece. The recessed portion is spaced from the second section of the center hole, preventing the recessed portion from transmitting pressure generated by the tensioning portion to the workpiece. This reduces the extent of the workpiece's outer wall protrusion, thereby improving workpiece machining accuracy.

[0034] According to a fourth aspect of the present invention, a clamp is used to clamp a workpiece having a central hole and a plurality of through holes arranged around the central hole, the clamp comprising: a chuck;

[0035] A plurality of claws connected to the chuck and arranged around the central axis of the chuck, the claws including a limiting portion, the plurality of limiting portions being able to pass through the central hole and abut against the hole wall of the central hole;

[0036] a first positioning block, provided on the outer end surface of the chuck, the first positioning block being used for positioning and cooperating with one of the through holes;

[0037] Among them, the multiple claws can drive the limiting part to move along the direction of the hole wall close to the center hole. When the multiple claws clamp the workpiece, the limiting part abuts against the first hole section of the center hole, and the first hole section is the hole section of the through hole corresponding to the center hole along the radial direction of the workpiece.

[0038] The clamp according to the embodiment of the utility model has at least the following beneficial effects:

[0039] The clamp is provided with a plurality of jaws connected to the chuck and arranged around the central axis of the chuck, and a limiting portion is provided on the jaw, which can be passed through the center hole and abut against the hole wall of the center hole, and the first positioning block is provided on the outer end face of the chuck. When the workpiece needs to be fixed, the workpiece is sleeved on the limiting portion through the center hole, and at the same time, a through hole of the workpiece and the first positioning block are positioned and matched, thereby determining the relative position of the workpiece and the clamp. When the jaw moves along the hole wall close to the center hole, the limiting portion abuts against the first hole section of the center hole, and the plurality of limiting portions cooperate to fix the position of the workpiece. Since the first hole section is a through hole corresponding to the hole section of the center hole along the radial direction of the workpiece, the pressure generated by the clamp can be reduced and transmitted to the outer wall of the workpiece, thereby reducing the amplitude of the bulge of the outer wall of the workpiece, and improving the processing accuracy of the workpiece.

[0040] According to some embodiments of the present invention, the hole segment corresponding to the center hole along the radial direction of the workpiece between two adjacent through holes is the second hole segment of the center hole, and the limiting portion is provided with a recess on the side facing the center hole, and the recess is configured to be spaced apart from the second hole segment when multiple claws clamp the workpiece.

[0041] According to some embodiments of the present invention, along the radial direction of the clamp, the maximum depth of the recess is H, which satisfies: 5 μm≤H≤1000 μm.

[0042] According to some embodiments of the present invention, the clamping claw further includes a supporting portion, which is connected to a side of the limiting portion away from the central axis of the chuck, and the supporting portion is used to abut against the end face of the workpiece.

[0043] According to some embodiments of the present invention, the clamp further includes a positioning portion, which is connected to the outer end surface of the chuck, and the positioning portion is used to abut against the end surface of the workpiece.

[0044] According to some embodiments of the present invention, the positioning portion is annular and is disposed around the plurality of limiting portions; or,

[0045] The positioning parts are provided in plurality and are arranged at intervals on the outer end surface of the chuck, and the plurality of positioning parts are arranged around the plurality of limiting parts.

[0046] According to some embodiments of the present invention, the positioning portion and the chuck are detachably connected.

[0047] According to some embodiments of the present invention, the fixture also includes a second positioning block, which is connected to the outer end surface of the chuck, and the second positioning block and the first positioning block are spaced apart, and the second positioning block is used to position and cooperate with another through hole of the workpiece.

[0048] According to some embodiments of the present invention, the first positioning block and the chuck are detachably connected, a plurality of mounting positions are provided at intervals on the outer end surface of the chuck, and the first positioning block is connected to one of the mounting positions.

[0049] According to some embodiments of the present invention, the outer end surface of the chuck is provided with a plurality of guide grooves having the same number as the claws, the plurality of guide grooves are radially distributed, the plurality of claws are correspondingly provided in the plurality of guide grooves, and can slide along the extension direction of the guide grooves.

[0050] The machine tool according to the fifth embodiment of the present invention includes the fixture described in the above embodiment.

[0051] The machine tool according to the embodiment of the utility model has at least the following beneficial effects:

[0052] By adopting the clamp of the fourth embodiment, the clamp is connected to the chuck by setting a plurality of jaws and is arranged around the central axis of the chuck, and a limiting portion is provided on the jaws, and the limiting portion can be passed through the center hole and abut against the hole wall of the center hole, and the first positioning block is set on the outer end face of the chuck. When the workpiece needs to be fixed, the workpiece is sleeved on the limiting portion through the center hole, and at the same time, a through hole of the workpiece and the first positioning block are positioned and matched, so as to determine the relative position of the workpiece and the clamp. When the jaws move along the hole wall close to the center hole, the limiting portion abuts against the first hole section of the center hole, and the plurality of limiting portions cooperate to fix the position of the workpiece. Since the first hole section is a through hole corresponding to the hole section of the center hole along the radial direction of the workpiece, the pressure generated by the clamp can be reduced and transmitted to the outer wall of the workpiece, so as to reduce the amplitude of the bulge of the outer wall of the workpiece, and the processing accuracy of the workpiece can be improved.

[0053] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0055] Figure 1 This is a schematic structural diagram of a clamp according to the first embodiment of the present invention;

[0056] Figure 2 This is a structural diagram of a clamp holding a cycloid wheel according to the first embodiment of the utility model;

[0057] Figure 3 This is an exploded view of the clamp of the first embodiment of the present utility model;

[0058] Figure 4 This is a schematic structural diagram of the support portion and the tensioning portion of the first embodiment of the utility model;

[0059] Figure 5 This is a schematic diagram of the structure of the first embodiment of the present utility model, showing the cooperation between the partial structure of the clamp and the cycloid wheel;

[0060] Figure 6 This is a top view of the first embodiment of the utility model, in which the fixture is partially hidden and fits in with the cycloid wheel;

[0061] Figure 7 This is a structural schematic diagram of another embodiment of the present invention, in which a clamp clamps two cycloid wheels;

[0062] Figure 8 This is a partial structural sectional view of the clamp according to the first embodiment of the present utility model;

[0063] Figure 9 yes Figure 8 Enlarged view of point A in the middle;

[0064] Figure 10 This is a schematic diagram of the bottom structure of the clamping portion of the first embodiment of the present utility model;

[0065] Figure 11 This is a schematic structural diagram of the support portion and the tensioning portion of the second embodiment of the present utility model;

[0066] Figure 12 This is a schematic structural diagram of the ring portion and the tensioning portion separated in the second embodiment of the present utility model;

[0067] Figure 13 yes Figure 12 Enlarged view of point B in the middle;

[0068] Figure 14 is a cross-sectional view of a clamp according to a third embodiment of the present invention;

[0069] Figure 15 This is a schematic diagram of the end face structure of the expansion sleeve of the third embodiment of the present utility model;

[0070] Figure 16 This is a schematic structural diagram of a clamp according to a third embodiment of the present invention;

[0071] Figure 17 This is a simplified schematic diagram of the clamp structure of the fourth embodiment of the present utility model;

[0072] Figure 18 This is a schematic structural diagram of a clamp according to a fifth embodiment of the present invention;

[0073] Figure 19 This is a schematic structural diagram of a clamp holding a cycloid wheel according to a fifth embodiment of the present invention;

[0074] Figure 20 This is a simplified top view of a clamp holding a cycloid wheel according to a fifth embodiment of the present invention;

[0075] Figure 21 This is a schematic structural diagram of a clamp according to a sixth embodiment of the present invention;

[0076] Figure 22 It is a simplified schematic top view of a clamp according to a sixth embodiment of the present invention.

[0077] Reference numerals:

[0078] fixture 1000;

[0079] Tensioning portion 100; convex portion 110; concave portion 120; main body 130; liquid inlet channel 131; liquid storage tank 132; flexible ring 140; positioning seat 150; positioning step 160; connecting shaft 170; tensioning assembly 180;

[0080] Support portion 200; first positioning block 210; ejector pin 211; second positioning block 220; mounting seat 230; rivet 231; positioning groove 240; first abutting portion 250; avoidance hole 260; support assembly 270;

[0081] Clamping portion 300; clamping space 310; fastener 320; second abutting portion 330; positioning hole 340;

[0082] Ring piece portion 400; positioning protrusion 410;

[0083] Cycloid wheel 500; center hole 510; special-shaped hole 520; crankshaft hole 530;

[0084] Elastic portion 610; fan-shaped portion 620; tapered hole 630;

[0085] Bracket 700; Pushing member 710; Conical rod 720; Conical surface 721;

[0086] Chuck 800 ; outer end surface 801 ; claw 810 ; limiting portion 820 ; recess 120 ; supporting portion 830 ; positioning portion 840 ; mounting position 850 ; guide groove 860 . DETAILED DESCRIPTION

[0087] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0088] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientation or positional relationships, 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 therefore cannot be understood as a limitation on the present invention.

[0089] In the description of this utility model, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0090] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0091] In the related art, the RV reducer includes a planetary carrier, a crankshaft and a cycloidal wheel. A center hole is provided at the center of the cycloidal wheel, and a plurality of crankshaft holes and a plurality of special-shaped holes are provided around the center hole. The special-shaped hole is used for the support column of the planetary carrier to pass through. Since the movement area required for the support column is large, the opening area of ​​the special-shaped hole is also relatively large. The crankshaft needs to pass through the crankshaft hole. Since the movement area required for the crankshaft is small, the opening area of ​​the crankshaft hole is usually smaller than the opening area of ​​the special-shaped hole. When processing the outer tooth portion of the cycloidal wheel, a clamp is needed to fix the cycloidal wheel. The expansion sleeve of the clamp is fixed to the hole wall of the cycloidal wheel by increasing the outer diameter.

[0092] During the tightening process, the pressure generated by the tightening part is easily transmitted to the outer wall of the cycloid wheel, causing the outer wall of the cycloid wheel to bulge. Since the structural connectivity between the outer wall of the cycloid wheel corresponding to the special-shaped hole and the area near the center hole is weak, the pressure generated by the tightening part is difficult to transmit to the outer wall of the cycloid wheel corresponding to the special-shaped hole, that is, the outer wall of the cycloid wheel corresponding to the special-shaped hole is rarely deformed by the tightening part. However, the outer wall of the cycloid wheel corresponding to the adjacent special-shaped holes is prone to bulge. After the outer tooth portion of the cycloid wheel is processed and the clamp is released, the protruding outer wall of the cycloid wheel will shrink, causing the radial runout of the outer tooth portion to deteriorate and the pitch error to increase.

[0093] For this purpose, refer to Figure 1 、 Figure 2 and Figure 3As shown, the fixture 1000 of the first embodiment of the present invention can be used to clamp a workpiece, such as a cycloid wheel 500, a gear, a bushing, a rigid wheel, etc. For the sake of convenience, the following description will take the clamping of the cycloid wheel 500 and the processing of the external teeth as an example. The cycloid wheel 500 has a center hole 510, and a plurality of through holes are arranged around the center hole 510, some of which are special-shaped holes 520, and other through holes are crankshaft holes 530. The fixture 1000 of the first embodiment of the present invention includes a tensioning assembly 180, a support assembly 270, and a clamping portion 300. The tensioning assembly 180 is connected to the support assembly 270. The support assembly 270 includes a support portion 200, which is used to support the end face of the cycloid wheel 500. The tensioning assembly 180 includes a tensioning portion 100, which can be passed through the center hole 510, and the outer wall of the tensioning portion 100 can move in a direction close to or away from the hole wall of the center hole 510, that is, the outer diameter of the tensioning portion 100 can increase or decrease. When the outer diameter increases, the cycloid wheel 500 can be clamped, and when the outer diameter decreases, the cycloid wheel 500 can be removed or installed.

[0094] The support portion 200 is connected to the tensioning portion 100, and the clamping portion 300 is connected to the tensioning portion 100 and is spaced apart from the support portion 200. Figure 1 In the illustrated orientation, the support portion 200 and the clamping portion 300 are spaced apart in the vertical direction, with the support portion 200 located below the clamping portion 300. A clamping space 310 for clamping a workpiece is formed between the clamping portion 300 and the support portion 200. The cycloid wheel 500 is sleeved on the tensioning portion 100 through the center hole 510. The support portion 200 provides positioning support, while the clamping portion 300 is used to limit the axial displacement of the cycloid wheel 500, and the tensioning portion 100 is used to limit the radial displacement of the cycloid wheel 500.

[0095] Among them, reference Figure 4 As shown, the outer wall of the tensioning part 100 is provided with a plurality of convex parts 110, and the plurality of convex parts 110 are arranged at intervals along the circumference of the tensioning part 100. Concave parts 120 are formed between adjacent convex parts 110, and the concave parts 120 and the convex parts 110 can be connected in a smooth transition or directly form a step surface. Figure 5 and Figure 6 As shown, when the radial position of the cycloid wheel 500 needs to be fixed, the cycloid wheel 500 is sleeved on the tensioning part 100 through the center hole 510. The outer diameter of the tensioning part 100 is increased, so that the side wall of the protrusion 110 and the first hole section of the center hole 510 are in abutment with each other, thereby improving the reliability and stability of the limit. The side wall of the recess 120 and the second hole section of the center hole are arranged at intervals, which can prevent the recess 120 from transmitting pressure to the cycloid wheel 500. It should be noted that in order to facilitate understanding of the positional relationship between the protrusion 110 and the recess 120 and the center hole 510 of the cycloid wheel 500, Figure 6The depth of the concave portion 120 in the radial direction is increased to a certain extent, and the depth of the concave portion 120 in an actual product can be designed according to corresponding conditions.

[0096] It is understood that by adopting the above solution, the support portion 200 and the clamping portion 300 are used to fix the axial position of the cycloid wheel 500. The side wall of the protrusion 110 abuts the first hole segment of the center hole 510, and the side wall of the recess 120 is spaced apart from the second hole segment of the center hole 510. Therefore, while ensuring the limiting stability of the protrusion 110, it also prevents the recess 120 from transmitting pressure to the cycloid wheel 500. The amplitude of the outer wall protrusion of the cycloid wheel 500 can be reduced, thereby improving the processing accuracy of the cycloid wheel 500 and reducing the radial runout and pitch error of the cycloid wheel 500.

[0097] It should be noted that the first hole segment refers to the hole segment of the through hole corresponding to the center hole 510 along the radial direction of the workpiece. For example, the first hole segment is the hole segment of the special-shaped hole 520 corresponding to the center hole 510 along the radial direction of the cycloid wheel 500. The hole segment of the special-shaped hole 520 corresponding to the center hole 510 along the radial direction of the cycloid wheel 500 refers to: Figure 6 As shown, the central angle corresponding to the maximum arc length of the special-shaped hole 520 in the circumferential direction of the cycloid wheel 500 is α, and the hole section of the center hole 510 corresponding to the central angle α is the first hole section corresponding to the special-shaped hole 520. Among them, the arc length corresponding to the outer wall of the protrusion 110 is less than or equal to the arc length of the hole wall corresponding to the central angle α. The central angle corresponding to the maximum arc length of two adjacent special-shaped holes 520 in the circumferential direction of the cycloid wheel 500 is β, and the hole section of the center hole 510 corresponding to the central angle β is the second hole section corresponding to the two adjacent special-shaped holes 520. It should also be noted that since the crankshaft hole 530 on the cycloid wheel 500 has a small aperture, the pressure generated by the tensioning part 100 is also easily transmitted to the outer wall of the cycloid wheel 500 corresponding to the crankshaft hole 530, so the hole section corresponding to the crankshaft hole 530 and the recess 120 correspond to each other.

[0098] In another embodiment, when the diameters of the crankshaft hole 530 and the irregularly shaped hole 520 are relatively large, that is, to effectively reduce the pressure transmitted from the fixture 1000 to the outer wall of the cycloidal wheel 500, the first hole segment may also be the segment of the crankshaft hole 530 corresponding to the center hole 510 along the radial direction of the cycloidal wheel 500. For example, the segments of the center hole 510 corresponding to the crankshaft hole 530 and the irregularly shaped hole 520 are both considered the first hole segment. The second hole segment is the segment of the center hole 510 between adjacent crankshaft holes 530 and irregularly shaped holes 520, as well as the segment of the center hole 510 corresponding to adjacent irregularly shaped holes 520.

[0099] In another embodiment, when the diameter of the irregularly shaped hole 520 is small and the diameter of the crankshaft hole 530 is large, that is, when the pressure generated by the fixture 1000 can be transmitted to the outer wall of the cycloidal wheel 500 through the structure surrounding the irregularly shaped hole 520 but is difficult to be transmitted to the outer wall of the cycloidal wheel 500 through the crankshaft hole 530, only the hole section of the crankshaft hole 530 corresponding to the center hole 510 along the radial direction of the cycloidal wheel 500 is the first hole section. The second hole section is the hole section of the center hole 510 corresponding to adjacent crankshaft holes 530.

[0100] In summary, the larger the opening area of ​​crankshaft hole 530 and the irregularly shaped hole 520, and the closer the opening is to center hole 510, the less likely the hole segment corresponding to center hole 510 will transmit pressure from fixture 1000 to the outer teeth of cycloidal gear 500. Therefore, the hole segment corresponding to center hole 510 with the larger opening area can be defined as the first hole segment, and the remaining hole segments other than the first hole segment can be defined as the second hole segment.

[0101] Reference Figure 6 As shown, in an embodiment of the present invention, along the radial direction of the tensioning portion 100, the maximum distance H between the sidewalls of the convex portion 110 and the sidewalls of the concave portion 120 satisfies the following: 5μm ≤ H ≤ 1000μm. For example, H can be 5μm, 20μm, 50μm, 100μm, 200μm, 400μm, 800μm, 1000μm, etc. When H is less than 5μm, the maximum distance H between the sidewalls of the convex portion 110 and the sidewalls of the concave portion 120 is too small, which can easily cause the sidewalls of the concave portion 120 to abut against the hole wall, resulting in a bulge in the outer wall of the cycloidal wheel 500 and reduced machining accuracy. When H is greater than 1000μm, the maximum distance H between the sidewalls of the convex portion 110 and the sidewalls of the concave portion 120 is too large. When the tensioning portion 100 needs to expand through flexible deformation, the strength of the tensioning portion 100 is reduced, making it prone to rupture. Therefore, by reasonably designing the size of H between 5μm and 1000μm, the abutment between the side wall of the recess 120 and the hole wall can be effectively reduced, the processing accuracy of the cycloid wheel 500 can be improved, and at the same time, the tensioning part 100 has appropriate strength, thereby improving the reliability of the tensioning part 100.

[0102] Reference Figure 4 and Figure 5As shown, in an embodiment of the present invention, a first positioning block 210 is fixedly connected to the side of the support portion 200 facing the clamping portion 300. The first positioning block 210 is located within the clamping space 310 and is used to align with one of the through holes of the cycloid wheel 500. This through hole can be a crankshaft hole 530 (or a special-shaped hole 520), thereby allowing the cycloid wheel 500 to mate with the corresponding protrusion 110 and recess 120. For example, because the support portion 200 and the tensioning portion 100 are fixedly connected, while the clamping portion 300 is typically detachably connected to the tensioning portion 100, the relative positions of the support portion 200 and the tensioning portion 100 are fixed. This facilitates direct positioning of the cycloid wheel 500, the protrusion 110, and the recess 120 when the cycloid wheel 500 is mounted on the tensioning portion 100, and thus improves clamping efficiency and accuracy. As an alternative embodiment, the first positioning block 210 can be omitted and manual alignment can be performed.

[0103] Since the RV reducer generally includes a plurality of cycloid wheels 500, for this purpose, Figure 7 As shown, in an embodiment of the present invention, the fixture 1000 can simultaneously clamp multiple cycloid wheels 500 for machining, for example, simultaneously clamping two cycloid wheels 500 to ensure that the machining accuracy of the two cycloid wheels 500 is substantially consistent. The axial height of the first positioning block 210 can adapt to multiple cycloid wheels 500, that is, it can simultaneously position and align with the crankshaft holes 530 of two or more cycloid wheels 500.

[0104] Reference Figure 4 As shown, in an embodiment of the present invention, the fixture 1000 further includes a pin 211 and an elastic member. The side wall of the first positioning block 210 is provided with a mounting hole, the elastic member is disposed within the mounting hole, one end of the pin 211 is disposed within the mounting hole and connected to the elastic member, and the other end of the pin 211 protrudes from the mounting hole. It is understood that the elastic member can be a spring, an elastic rubber member, a silicone member, etc. By utilizing the cooperation between the pin 211 and the elastic member, the pin 211 can abut against the side wall of the crankshaft hole 530 under the elastic force of the elastic member, thereby reducing the circumferential swing of the cycloid wheel 500, thereby improving the positioning accuracy of the cycloid wheel 500.

[0105] Reference Figure 4 and Figure 5As shown, in an embodiment of the present invention, a second positioning block 220 located in the clamping space 310 is fixedly connected to the side of the support portion 200 facing the clamping portion 300. The second positioning blocks 220 are arranged at intervals along the circumference of the tensioning portion 100. The second positioning blocks 220 are used to position and cooperate with another through hole of the cycloid wheel 500. This through hole can be a special-shaped hole 520 (or a crankshaft hole 530). It can be understood that due to the larger opening area of ​​the special-shaped hole 520, the positioning of the cycloid wheel 500 is more convenient. Therefore, the second positioning block 220 can achieve rough positioning, while the first positioning block 210 achieves fine positioning, which can further improve the positioning efficiency and facilitate the rapid alignment of the hole wall of the cycloid wheel 500 and the convex portion 110 and the concave portion 120.

[0106] Reference Figure 8 and Figure 9 As shown, in an embodiment of the present invention, the tensioning portion 100 includes a main body 130 and a flexible collar 140. The main body 130 is provided with a liquid inlet channel 131, and the outer wall of the main body 130 is surrounded by a liquid reservoir 132. The flexible collar 140 is fixedly connected to the outer wall of the main body 130 and closes the opening of the liquid reservoir 132. A liquid storage space is formed between the flexible collar 140 and the liquid reservoir 132, communicating with the liquid inlet channel 131. For example, the liquid storage space may contain hydraulic oil. The outer wall of the flexible collar 140 is provided with a protrusion 110 and a recess 120. It is understood that a piston may be provided in the liquid inlet channel 131. By pushing the piston, the volume of the liquid inlet channel 131 is reduced, allowing the hydraulic oil to flow to the liquid reservoir 132. Because the flexible collar 140 is elastically deformable, it expands under the pressure of the hydraulic oil, thereby increasing its outer diameter and abutting against the hole wall to restrict the radial position of the cycloid wheel 500.

[0107] Reference Figure 8 As shown, in an embodiment of the present invention, the support portion 200 and the main body 130 are integrally formed, and the inlet of the liquid inlet channel 131 is arranged on the outer wall of the support portion 200. By arranging a screw at the inlet of the liquid inlet channel 131, the screw and the piston are connected. When the screw is tightened, it can drive the piston to move and squeeze the hydraulic oil, so that the outer diameter of the flexible ring sleeve 140 increases. When the screw is loosened, the outer diameter of the flexible ring sleeve 140 is reduced, which facilitates the removal of the cycloid wheel 500 or the installation of a new cycloid wheel 500. As an alternative embodiment, the tensioning portion 100 can also be automatically loosened or released by the oil supply system, and the appropriate solution can be selected according to the actual situation.

[0108] Reference Figure 1 、 Figure 4 and Figure 10As shown, in an embodiment of the present invention, the clamping portion 300 is detachably connected to the tensioning portion 100, thereby facilitating the installation of the cycloid wheel 500. The detachable connection method can be: a positioning seat 150 is provided at one end of the tensioning portion 100 away from the support portion 200, and the maximum outer diameter of the positioning seat 150 is smaller than the maximum outer diameter of the tensioning portion 100, so that a positioning step 160 is formed at the end of the tensioning portion 100 facing the positioning seat 150, and the clamping portion 300 is provided with a positioning hole 340, and the clamping portion 300 is sleeved on the positioning seat 150 through the positioning hole 340 and abuts against the positioning step 160. A connecting shaft 170 is provided at one end of the positioning seat 150 away from the tensioning portion 100, and the clamp 1000 further includes a fastener 320, which is fixedly connected to the connecting shaft 170 and abuts against the clamping portion 300. The fastener 320 can be a nut, which is threadedly connected to the connecting shaft 170. By adopting this solution, the clamping portion 300 is easily disassembled and assembled, while also improving the stability and reliability of the cycloid wheel 500. Alternatively, the clamping portion 300 can be secured by bolts threaded through the support portion 200 and the clamping portion 300, or the clamping portion 300 can be directly threaded into the positioning seat 150. The clamping portion 300 and the tensioning portion 100 can also be detachably connected by a snap-fit ​​connection, with the appropriate solution selected depending on the actual situation.

[0109] Reference Figure 4 and Figure 10 As shown, in an embodiment of the present invention, a first abutting portion 250 is provided on the side of the support portion 200 facing the clamping portion 300, and the first abutting portion 250 is arranged along the extending direction of the edge of the support portion 200; a second abutting portion 330 is provided on the side of the clamping portion 300 facing the support portion 200, and the second abutting portion 330 is arranged along the extending direction of the edge of the clamping portion 300. For example, the first abutting portion 250 may include a plurality of first limiting segments, and the plurality of first limiting segments are arranged at intervals along the edge of the support portion 200. The second abutting portion 330 may include a plurality of second limiting segments, and the plurality of second limiting segments are arranged at intervals along the edge of the clamping portion 300. Alternatively, both the first abutting portion 250 and the second abutting portion 330 may be completely annular. It can be understood that by setting the first abutment portion 250 and the second abutment portion 330 to abut against the cycloid wheel 500, it is only necessary to fine-machine the first abutment portion 250 and the second abutment portion 330, and there is no need to fine-machine the entire end surface of the support portion 200 and the clamping portion 300. This can reduce production costs while improving the accuracy of clamping and positioning.

[0110] Reference Figure 1As shown, in this embodiment of the present invention, a mounting base 230 is provided at the lower end of the support portion 200, and a pull pin 231 is provided at the lower end of the mounting base 230. The fixture 1000 is used to securely connect to processing equipment such as a gear hobbing machine or a gear shaping machine. By tightening the pull pin 231, the processing equipment causes the inclined surfaces at the interface between the mounting base 230 and the processing equipment to abut and mate, thereby fixing the relative positions of the fixture 1000 and the processing equipment.

[0111] Since the tensioning part 100 is provided with the convex part 110 and the concave part 120, it may be necessary to replace the entire fixture 1000 when processing different types of cycloid wheels 500, which is costly. Figure 11 and Figure 12 As shown, the clamp 1000 of the second embodiment of the present invention can be used to clamp a workpiece, for example, the workpiece can be a cycloid wheel 500, a gear, a bushing, a rigid wheel, etc. For the convenience of explanation, the clamping of the cycloid wheel 500 is used to process the outer tooth portion as an example. The cycloid wheel 500 has a center hole 510, and a plurality of through holes are arranged around the center hole 510, some of which are special-shaped holes 520, and the other part of the through holes are crankshaft holes 530. The clamp 1000 of the embodiment of the present invention includes a tensioning assembly 180, a support assembly 270, a clamping portion 300 and a ring portion 400, and the tensioning assembly 180 is connected to the support assembly 270. The support assembly 270 includes a support portion 200, and the support portion 200 is used to support the end face of the cycloid wheel 500. The tensioning assembly 180 includes a tensioning portion 100, which can be passed through the center hole 510, and the outer wall of the tensioning portion 100 can move in a direction away from the center axis of the clamp 1000, that is, the outer diameter of the tensioning portion 100 can increase or decrease. When the outer diameter increases, the cycloid wheel 500 can be clamped, and when the outer diameter decreases, the cycloid wheel 500 can be removed or installed.

[0112] The support portion 200 is connected to the tensioning portion 100. The clamping portion 300 is connected to the end of the tensioning portion 100 facing away from the support portion 200 and is spaced apart from the support portion 200. A clamping space 310 is formed between the clamping portion 300 and the support portion 200 for clamping the cycloid gear 500. The cycloid gear 500 is sleeved onto the tensioning portion 100 through a center hole 510. The support portion 200 provides positioning support, while the clamping portion 300 limits the axial displacement of the cycloid gear 500, and the tensioning portion 100 limits its radial displacement.

[0113] Among them, the annular portion 400 can be sleeved on the outer side wall of the tensioning portion 100, and the annular portion 400 can produce flexible deformation, that is, the outer diameter can also increase or decrease under the drive of the tensioning portion 100. The outer side wall of the annular portion 400 is provided with a plurality of protrusions 110, and the plurality of protrusions 110 are arranged at intervals along the circumference of the annular portion 400. A recess 120 is formed between adjacent protrusions 110, and the recess 120 and the protrusion 110 can be connected in a smooth transition or directly form a step surface. When it is necessary to fix the radial position of the cycloid wheel 500, the cycloid wheel 500 is sleeved on the annular portion 400 through the center hole 510. The increase in the outer diameter of the tensioning portion 100 drives the increase in the outer diameter of the annular portion 400, so that the side wall of the protrusion 110 and the first hole section of the center hole 510 abut and cooperate, thereby improving the reliability and stability of the limit. The sidewall of the recess 120 and the second hole segment of the central hole are spaced apart to prevent the recess 120 from transmitting pressure to the cycloid wheel 500. It should be noted that the definitions of the first hole segment and the second hole segment refer to those in the fixture of the first embodiment and are not repeated here.

[0114] It is understood that by adopting the above solution, the support portion 200 and the clamping portion 300 are used to fix the axial position of the cycloid wheel 500. The side wall of the protrusion 110 abuts the first hole segment of the center hole 510, and the side wall of the recess 120 is spaced apart from the second hole segment of the center hole 510. This ensures the stability of the protrusion 110 while preventing the recess 120 from transmitting pressure to the cycloid wheel 500. This can reduce the amplitude of the outer wall protrusion of the cycloid wheel 500, thereby improving the processing accuracy of the cycloid wheel 500 and reducing the radial runout and pitch error of the cycloid wheel 500. At the same time, the solution of the ring plate portion 400 being sleeved on the tensioning portion 100 allows for convenient replacement of different types of ring plate portions 400 without having to replace the entire fixture 1000, thereby reducing production costs.

[0115] In order to quickly determine the relative position between the ring piece portion 400 and the tensioning portion 100, refer to Figure 12 and Figure 13 As shown, in the embodiment of the present invention, the ring piece portion 400 is provided with one of the positioning groove 240 and the positioning protrusion 410 at one end facing the support portion 200, and the support portion 200 is provided with the other of the positioning groove 240 and the positioning protrusion 410 at one side facing the ring piece portion 400, and the positioning protrusion 410 and the positioning groove 240 are positioned and matched. Figure 13In the embodiment, the ring segment 400 is provided with a plurality of positioning protrusions 410 on one end facing the support portion 200, and the plurality of positioning protrusions 410 are spaced apart along the circumference of the ring segment 400. The support portion 200 is provided with a plurality of positioning grooves 240 on the side facing the ring segment 400, and the plurality of positioning grooves 240 are spaced apart along the circumference of the tensioning portion 100. By providing the plurality of positioning protrusions 410 and the plurality of positioning grooves 240 for positioning and coordinating, the position of the ring segment 400 can be quickly determined, ensuring that the protrusion 110 and the recess 120 mate with the corresponding hole wall of the cycloidal wheel 500.

[0116] It should be noted that, in the second embodiment using the ring sheet portion 400 , except for the design positions of the convex portion 110 and the concave portion 120 , other structures and beneficial effects are similar to those of the first embodiment described above, and will not be described in detail here.

[0117] Reference Figure 14 、 Figure 15 and Figure 16 As shown, the third embodiment of the present invention, the clamp 1000, can be used to clamp a workpiece, for example, the workpiece can be a cycloid wheel 500, a gear, a bushing, a rigid wheel, etc. For the sake of convenience, the clamping of the cycloid wheel 500 and the processing of the outer teeth are used as an example for explanation. The clamp 1000 of the present invention embodiment includes a support portion 200, an expansion sleeve 600 and a tapered rod 720. The support portion 200 is provided with an avoidance hole 260; the expansion sleeve 600 is inserted into the avoidance hole 260 and is spaced apart from the hole wall of the avoidance hole 260. The expansion sleeve 600 includes a plurality of fan-shaped portions 620 and a plurality of elastic portions 610. The plurality of fan-shaped portions 620 are spaced apart circumferentially along the central axis of the clamp 1000. An elastic portion 610 is provided between adjacent fan-shaped portions 620. The elastic portion 610 can be a sheet structure made of rubber or silicone. A tapered hole 630 is formed between the plurality of elastic portions 610 and the plurality of fan-shaped portions 620 at one end facing the central axis. The cross-sectional area of ​​the tapered hole 630 gradually increases along the central axis, that is, the tapered hole 630 is a tapered hole. Therefore, the cross-sectional area of ​​the tapered hole 630 gradually increases from right to left.

[0118] Reference Figure 14 As shown, the conical rod 720 is inserted into the conical hole 630 and has a conical surface 721 that abuts the sidewall of the conical hole 630. The conical rod 720 is used to move the sector 620 in a direction away from the central axis of the expansion sleeve 600. That is, the sector 620 and the elastic portion 610 are merely in abutment with each other and can separate under the action of an external force. Therefore, pushing the conical rod 720 can drive the sector 620 to move away from the central axis of the expansion sleeve 600, thereby abutting against the hole wall of the cycloid wheel 500. Therefore, the separation between the expansion sleeve 600 and the hole wall of the avoidance hole 260 is intended to prevent the hole wall of the avoidance hole 260 from affecting the swinging of the sector 620 and the elastic portion 610.

[0119] Among them, along the radial direction of the tensioning part 100, the end of the fan-shaped part 620 away from the central axis protrudes from the end of the elastic part 610 away from the central axis, the outer wall of the fan-shaped part 620 can abut against the hole wall of the cycloid wheel 500, and the outer wall of the elastic part 610 can be spaced apart from the hole wall of the cycloid wheel 500.

[0120] It is understood that by adopting the above solution, pushing the tapered rod 720 causes the sector 620 to move in a direction away from the central axis of the expansion sleeve 600, that is, the outer diameter of the expansion sleeve 600 increases and abuts against the hole wall of the cycloid wheel 500, thereby limiting the position of the cycloid wheel 500. By abutting the corresponding hole walls of the sector 620 and the corresponding hole walls of the irregularly shaped holes 520, the elastic portion 610 and the corresponding hole walls of adjacent irregularly shaped holes 520 are spaced apart. While ensuring the stability of the sector 620's positional limitation, it also prevents the elastic portion 610 from transmitting pressure to the cycloid wheel 500, thereby reducing the amplitude of the outer wall protrusion of the cycloid wheel 500, thereby improving the processing accuracy of the cycloid wheel 500 and reducing the radial runout and pitch error of the cycloid wheel 500.

[0121] Reference Figure 16 As shown, in an embodiment of the present invention, a first positioning block 210 is provided on the outer end surface of the support portion 200. The first positioning block 210 is used to position and cooperate with the crankshaft hole 530 or the special-shaped hole 520 of the cycloid wheel 500, so that the cycloid wheel 500 cooperates with the fan-shaped portion 620 and the elastic portion 610 at the corresponding position. At the same time, a second positioning block 220 can also be provided on the outer end surface of the support portion 200. The second positioning block 220 can be positioned and cooperated with the crankshaft hole 530 or the special-shaped hole 520 of the cycloid wheel 500. For example, the first positioning block 210 is positioned and cooperated with the crankshaft hole 530, and the second positioning block 220 is positioned and cooperated with the special-shaped hole 520. The second positioning block 220 plays a role of rough positioning, and the first positioning block 210 plays a role of fine positioning, which can improve the efficiency of positioning.

[0122] Reference Figure 14 As shown, in an embodiment of the present invention, the clamp 1000 further includes a pusher 710 and a bracket 700, and the support portion 200 is fixedly connected to the bracket 700. The bracket 700 is a hollow structure, and the pusher 710 is slidably connected to the bracket 700 and fixedly connected to the tapered rod 720. The pusher 710 can drive the push rod to move, so that the fan-shaped portion 620 moves in a direction away from the central axis of the expansion sleeve 600 to clamp the cycloid wheel 500. The clamp 1000 can be connected to a processing device such as a gear shaping machine or a gear hobbing machine through the bracket 700.

[0123] A machine tool according to an embodiment of the present invention includes the fixture 1000 of the above embodiment. The machine tool may be a gear grinding machine, a gear hobbing machine, a compound machine tool with gear grinding or gear hobbing function, a grinder, a milling machine, a lathe, etc. The machine tool according to the embodiment of the present invention adopts the fixture 1000 of the above embodiment, and uses the support part 200 and the clamping part 300 to fix the cycloid wheel 500 in the axial direction. The side wall of the protrusion 110 abuts the first hole section of the center hole 510, and the side wall of the recess 120 and the second hole section of the center hole 510 are spaced apart. Therefore, while ensuring the limiting stability of the protrusion 110, it is also possible to prevent the recess 120 from transmitting pressure to the cycloid wheel 500, and reduce the amplitude of the outer wall protrusion of the cycloid wheel 500, so as to improve the processing accuracy of the cycloid wheel 500 and reduce the radial runout and pitch error of the cycloid wheel 500.

[0124] Reference Figure 17 As shown, a clamp 1000 of an embodiment of the utility model can be used to clamp a workpiece, for example, the workpiece can be a cycloid wheel 500, a gear, a bushing, a rigid wheel, etc. For the convenience of explanation, the clamping of the cycloid wheel 500 is used as an example. The cycloid wheel 500 is provided with a center hole 510 and a plurality of through holes arranged around the center hole 510. A part of the plurality of through holes is a special-shaped hole 520, and the other part is a crankshaft hole 530.

[0125] Reference Figure 17 and Figure 18 As shown, the clamp 1000 of the embodiment of the present invention includes a chuck 800, a clamping jaw 810 and a first positioning block 210. The clamping jaw 810 is provided in plurality and is connected to the chuck 800 and is arranged around the central axis of the chuck 800. The clamping jaw 810 includes a limiting portion 820, which can be arranged through the center hole 510 of the cycloid wheel 500 and abut against the hole wall of the center hole 510. The first positioning block 210 is set on the outer end surface 801 of the chuck 800. Since one end of the chuck 800 needs to be fixedly connected to the machine tool, and the other end of the chuck 800 protrudes from the outside of the machine tool, the end of the chuck 800 exposed to the machine tool is called the outer end surface 801. The first positioning block 210 is used to position and cooperate with one of the through holes of the cycloid wheel 500, for example, the crankshaft hole 530 or the special-shaped hole 520. Among them, multiple claws 810 can drive the limiting part 820 to move along the direction of the hole wall close to the center hole 510. When multiple claws 810 clamp the workpiece, the limiting part 820 abuts against the first hole section 511 of the center hole 510. The first hole section 511 is a through hole corresponding to the center hole 510 along the radial direction of the workpiece. The through hole can be an irregular hole 520 or a crankshaft hole 530.

[0126] Reference Figure 4As shown, it should be noted that, taking the through hole as the special-shaped hole 520 as an example, the special-shaped hole 520 corresponding to the first hole segment 511 of the center hole 510 along the radial direction of the workpiece refers to: the central angle corresponding to the maximum arc length of the special-shaped hole 520 in the circumferential direction of the cycloid wheel 500 is α, and the hole segment of the center hole 510 corresponding to the special-shaped hole 520 within the range of the central angle α is the first hole segment 511 corresponding to the special-shaped hole 520. The limiting portion 820 abuts against at least a portion of the first hole segment 511.

[0127] It is understandable that, when the above solution is adopted and the cycloid wheel 500 needs to be fixed, the cycloid wheel 500 is sleeved on the limiting portion 820 through the center hole 510, and at the same time, a through hole of the cycloid wheel 500 is positioned and matched with the first positioning block 210, thereby determining the relative position of the cycloid wheel 500 and the fixture 1000. When the claw 810 moves along the hole wall direction close to the center hole 510, the limiting portion 820 abuts against the first hole section 511 of the center hole 510. Since the first hole section 511 is a through hole corresponding to the hole section of the center hole 510 along the radial direction of the cycloid wheel 500, it can reduce the pressure generated by the fixture 1000 and transmitted to the outer wall of the cycloid wheel 500, thereby reducing the amplitude of the protrusion of the outer wall of the cycloid wheel 500 and improving the processing accuracy of the cycloid wheel 500.

[0128] Reference Figure 17 As shown, in the fourth embodiment of the present invention, the outer wall of the limiting portion 820 can be a complete wall surface, and the outer wall of the limiting portion 820 abuts and cooperates with the first hole segment 511 of the center hole 510. The abutment between multiple limiting portions 820 and the first hole segment 511 not only fixes the position of the cycloid wheel 500, but also reduces the transmission of pressure from the limiting portions 820 to the outer wall of the cycloid wheel 500.

[0129] According to Figure 18 and Figure 20 As shown, in the fifth embodiment of the present invention, a recess 120 is provided on the side of the limiting portion 820 facing the center hole 510. The recess 120 is configured to be spaced apart from the second hole segment 512 of the center hole 510 when the multiple claws 810 clamp the cycloid wheel 500. The second hole segment 512 is the hole segment between two adjacent through holes corresponding to the center hole 510 along the radial direction of the cycloid wheel 500. The two adjacent through holes refer to two adjacent special-shaped holes 520, or may also be adjacent special-shaped holes 520 and crankshaft holes 530, or two adjacent crankshaft holes 530. For the sake of convenience, the explanation is based on the second hole segment 512 corresponding to the center hole 510 along the radial direction of the cycloid wheel 500 between two adjacent special-shaped holes 520.

[0130] Reference Figure 20As shown, the second hole segment 512 corresponding to the center hole 510 along the radial direction of the cycloid wheel 500 between two adjacent special-shaped holes 520 refers to: the central angle corresponding to the maximum arc length of the two adjacent special-shaped holes 520 in the circumferential direction of the cycloid wheel 500 is β, and the hole segment of the center hole 510 corresponding to the central angle β is the second hole segment 512 corresponding to the two adjacent special-shaped holes 520.

[0131] It can be understood that, by adopting the above scheme, since the recess 120 and the second hole section 512 of the center hole 510 are arranged at intervals, the limiting portion 820 can effectively reduce the pressure transmitted to the outer wall of the cycloid wheel 500 through the structure between adjacent special-shaped holes 520, so as to reduce the amplitude of the protrusion of the outer wall of the cycloid wheel 500, thereby improving the processing accuracy of the cycloid wheel 500 and reducing the radial runout and pitch error of the cycloid wheel 500.

[0132] Reference Figure 20 As shown, in an embodiment of the present invention, along the radial direction of the fixture 1000, the maximum depth of the recess 120 is H, which satisfies the following conditions: 5μm ≤ H ≤ 1000μm. For example, the value of H can be 5μm, 20μm, 50μm, 100μm, 200μm, 400μm, 800μm, 1000μm, etc. When H is less than 5μm, the maximum depth of the recess 120 is too shallow, which can easily cause the side walls of the recess 120 to abut against the hole wall of the center hole 510, thereby causing the outer wall of the cycloid wheel 500 to bulge and reduce the processing accuracy. When H is greater than 1000μm, the maximum depth of the recess 120 is too large, which can reduce the strength of the limiter 820 and make it easy to break. Therefore, by rationally designing the size of H between 5μm and 1000μm, the abutment between the side walls of the recess 120 and the hole wall can be effectively reduced, and the processing accuracy of the cycloid wheel 500 can be improved.

[0133] Reference Figure 18 and Figure 19 As shown, in an embodiment of the present invention, a limiting portion 820 is provided at one end of the clamping claw 810 facing the central axis, and the clamping claw 810 also includes a support portion 830 connected to the side of the limiting portion 820 away from the central axis of the chuck, and the upper end surface of the limiting portion 820 protrudes from the upper end surface of the support portion 830. The support portion 830 is used for abutting and positioning with the end surface of the cycloid wheel 500, that is, the upper end surface of the support portion 830 and the end surface of the cycloid wheel 500 are abutted and positioned. It can be understood that in the process of clamping the cycloid wheel 500, it is also necessary to keep the central axis of the cycloid wheel 500 and the central axis of the chuck 800 flush to avoid tilting during clamping. Therefore, by providing a support portion 830 for positioning the end face of the cycloid wheel 500 on the claw 810, the position of the cycloid wheel 500 can be limited so that the central axis of the cycloid wheel 500 is aligned with the central axis of the fixture 1000, thereby improving the processing accuracy of the cycloid wheel 500.

[0134] As an alternative embodiment, refer to Figure 21 As shown, in the sixth embodiment of the present invention, the clamp 1000 further includes a positioning portion 840, which is connected to the outer end surface 801 of the chuck 800. The positioning portion 840 is used to abut and position the end surface of the cycloid wheel 500. The positioning portion 840 can be a flat sheet or a block. It is understood that by providing the positioning portion 840 on the outer end surface 801 of the chuck 800, the cycloid wheel 500 can be positioned so that the central axis of the cycloid wheel 500 is aligned with the central axis of the clamp 1000, thereby improving the processing accuracy of the cycloid wheel 500.

[0135] Reference Figure 21 As shown, in the embodiment of the present invention, the positioning portion 840 is annular and is arranged around the plurality of limiting portions 820. By setting the positioning portion 840 in an annular shape, the flatness of the side where the positioning portion 840 and the cycloid wheel 500 abut can be ensured, and the unevenness of the positioning portion 840 can be effectively reduced. As an alternative embodiment, refer to Figure 22 As shown, a plurality of positioning portions 840 may be provided, with the plurality of positioning portions 840 being spaced apart and arranged on the outer end surface 801 of the chuck 800, and the plurality of positioning portions 840 being arranged around the plurality of limiting portions 820. By providing a plurality of positioning portions 840, the material usage of the positioning portions 840 can be reduced compared to the solution of providing an annular positioning portion 840, thereby reducing production costs.

[0136] It should be noted that due to friction and wear between the positioning portion 840 and the cycloid wheel 500, long-term use may cause the positioning portion 840 to be damaged, deformed, or other adverse effects. For this reason, in an embodiment of the utility model, the positioning portion 840 and the chuck 800 are detachably connected. When the positioning portion 840 is damaged, deformed, or the like, the positioning portion 840 can be disassembled and replaced with a new positioning portion 840 to increase the service life of the clamp 1000. The detachable connection method can be a fastener connection, a snap-on connection, or the like. For example, the positioning portion 840 is fixed to the outer end face 801 of the chuck 800 by a structure such as a screw or a bolt. When a screw is used, a recessed groove is provided on the positioning portion 840 so that the head of the screw can be in the recessed groove to prevent the head of the screw from protruding from the outer end of the positioning portion 840.

[0137] Reference Figure 18 and Figure 20As shown, in an embodiment of the present invention, the clamp 1000 further includes a second positioning block 220, which is connected to the outer end surface 801 of the chuck 800. The second positioning block 220 and the first positioning block 210 are spaced apart. The second positioning block 220 is used to position and cooperate with another through hole of the cycloid wheel 500, for example, with the special-shaped hole 520 or the crankshaft hole 530 of the cycloid wheel 500. It can be understood that by providing the first positioning block 210 and the second positioning block 220, the purpose is to make the limiting portion 820 and the recessed portion 120 correspond to the first hole section 511 and the second hole section 512 of the cycloid wheel 500. For example, the first positioning block 210 is positioned and cooperated with the crankshaft hole 530, and the second positioning block 220 is positioned and cooperated with the special-shaped hole 520. Since the cross-sectional area of ​​the irregularly shaped hole 520 is larger than that of the crankshaft hole 530, positioning of the irregularly shaped hole 520 is relatively simple, which facilitates rapid alignment of the cycloid wheel 500 and the limiting portion 820. The first positioning block 210 can be used for fine positioning, while the second positioning block 220 can be used for coarse positioning, to improve positioning efficiency.

[0138] In order to improve the versatility of the fixture 1000, refer to Figure 18 As shown, in an embodiment of the present invention, the first positioning block 210 and the chuck 800 are detachably connected, and the detachable connection can be connected by fasteners such as screws and bolts, or by a snap-on connection. The outer end surface 801 of the chuck 800 is provided with a plurality of mounting positions 850 at intervals, and the first positioning block 210 is connected to one of the mounting positions 850. It is understandable that by matching the first positioning block 210 with different mounting positions 850, the first positioning block 210 can be positioned and matched with the through holes of different models of cycloidal wheels 500, which can improve the versatility of the clamp 1000 and reduce production costs.

[0139] Reference Figure 18 As shown, in an embodiment of the present invention, the outer end surface 801 of the chuck 800 is provided with a plurality of guide grooves 860, the number of which is equal to the number of the clamping jaws 810. The plurality of guide grooves 860 are radially distributed, and the plurality of clamping jaws 810 are correspondingly provided in the plurality of guide grooves 860 and are capable of sliding along the extension direction of the guide grooves 860. Therefore, by pushing the clamping jaws 810 along the guide grooves 860, the limiting portion 820 can be moved toward or away from the central axis of the clamp 1000, thereby loosening or clamping the cycloid wheel 500.

[0140] A machine tool according to an embodiment of the present invention includes the fixture 1000 of the above embodiment. The machine tool may be a gear grinding machine, a gear hobbing machine, a compound machine tool with gear grinding or gear hobbing functions, a grinder, a milling machine, a lathe, etc. The machine tool according to the embodiment of the present invention adopts the fixture 1000 of the above embodiment, and is connected to the chuck 800 by setting a plurality of jaws 810 of the fixture 1000 and arranged around the central axis of the chuck 800. A limiting portion 820 is provided on the jaws 810, and the limiting portion 820 can be passed through the center hole 510 and abut against the hole wall of the center hole 510, and the first positioning block 210 is provided on the outer end surface 801 of the chuck 800. When it is necessary to fix the workpiece, the workpiece is sleeved on the limiting portion 820 through the center hole 510, and at the same time, a through hole of the workpiece is positioned and matched with the first positioning block 210, thereby determining the relative position of the workpiece and the fixture 1000. When the clamping jaw 810 moves along the hole wall close to the center hole 510, the limiting portion 820 abuts against the first hole section 511 of the center hole 510. Since the first hole section 511 is a through hole corresponding to the center hole 510 in the radial direction of the workpiece, the pressure generated by the clamp 1000 can be reduced from being transmitted to the outer wall of the workpiece, thereby reducing the extent of the bulge of the outer wall of the workpiece and improving the machining accuracy of the workpiece.

[0141] Since the machine tool adopts all the technical solutions of the fixture 1000 of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be described in detail here.

[0142] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A fixture for holding a workpiece having a central hole and a plurality of through holes arranged around the central hole, characterized in that: The fixture comprises: A support assembly, comprising a support portion for supporting the end face of the workpiece; a tensioning assembly connected to the support assembly, the tensioning assembly comprising a tensioning portion and a plurality of protrusions, the tensioning portion protruding from the support portion along the axial direction of the clamp and capable of being inserted into the center hole, the plurality of protrusions being connected to the sidewalls of the tensioning portion and spaced apart along the circumference of the tensioning portion, with recesses formed between adjacent protrusions; In which, the tightening part can drive the convex part to move in the direction close to or away from the hole wall of the center hole. When the tightening part abuts against the hole wall of the center hole, the convex part abuts against the first hole section of the center hole. The first hole section is the hole section of the through hole corresponding to the center hole along the radial direction of the workpiece. The recessed part and the second hole section of the center hole are arranged at intervals. The second hole section is the hole section between two adjacent through holes corresponding to the center hole along the radial direction of the workpiece.

2. The clamp according to claim 1, characterized in that: Along the radial direction of the tensioning portion, a maximum distance H between a side wall of the convex portion and a side wall of the concave portion satisfies: 5 μm≤H≤1000 μm.

3. The clamp according to claim 1, characterized in that: The support portion is fixedly connected to a first positioning block, and the first positioning block is used for positioning and matching with one of the through holes of the workpiece.

4. The clamp according to claim 3, characterized in that: The clamp also includes a ejector pin and an elastic member. The side wall of the first positioning block is provided with a mounting hole. The elastic member is arranged in the mounting hole. One end of the ejector pin is arranged in the mounting hole and connected to the elastic member. The other end of the ejector pin protrudes from the mounting hole. The ejector pin can abut against the side wall of the through hole under the elastic force of the elastic member.

5. The clamp according to claim 3, characterized in that: The support portion is fixedly connected to a second positioning block. Along the circumference of the tensioning portion, the second positioning block and the first positioning block are spaced apart. The second positioning block is used for positioning and cooperating with another through hole of the workpiece.

6. The clamp according to claim 1, characterized in that: The support assembly further includes a clamping portion, which is located on a side of the tensioning portion away from the support portion and spaced apart from the support portion. A clamping space for clamping the workpiece is formed between the clamping portion and the support portion.

7. The clamp according to claim 6, characterized in that: The clamping portion is detachably connected to the tightening portion.

8. The clamp according to claim 7, characterized in that: A positioning seat is provided at one end of the tensioning part away from the supporting part, the maximum outer diameter of the positioning seat is smaller than the maximum outer diameter of the tensioning part, a positioning step is formed at one end of the tensioning part facing the positioning seat, the clamping part is provided with a positioning hole, the clamping part is sleeved on the positioning seat through the positioning hole and abuts against the positioning step.

9. The clamp according to claim 8, characterized in that: A connecting shaft is provided at one end of the positioning seat away from the tensioning portion. The clamp further comprises a fastener fixedly connected to the connecting shaft and abutting against the clamping portion.

10. The clamp according to claim 7, wherein: A first abutment portion is provided on the side of the support portion facing the clamping portion, and the first abutment portion is provided along the extension direction of the edge of the support portion; a second abutment portion is provided on the side of the clamping portion facing the support portion, and the second abutment portion is provided along the extension direction of the edge of the clamping portion.

11. The clamp according to claim 1, characterized in that: The tensioning part includes a main body and a flexible ring sleeve, a liquid inlet channel is provided in the main body, a liquid storage tank is provided around the outer wall of the main body, the flexible ring sleeve is fixedly connected to the outer wall of the main body and covers the liquid storage tank, a liquid storage space connected to the liquid inlet channel is formed between the flexible ring sleeve and the inner wall of the liquid storage tank, and the outer wall of the flexible ring sleeve is provided with the convex portion and the concave portion.

12. The clamp according to claim 11, characterized in that: The support portion and the main body are integrally formed, and the inlet of the liquid inlet channel is arranged on the outer side wall of the support portion.

13. The clamp according to claim 1, wherein: The support portion is provided with an avoidance hole, the tensioning portion is passed through the avoidance hole and is spaced apart from the hole wall of the avoidance hole, the tensioning portion includes a plurality of fan-shaped portions and a plurality of elastic portions, the plurality of fan-shaped portions are spaced apart along the circumference of the clamp, the elastic portion is provided between adjacent fan-shaped portions, and the plurality of fan-shaped portions and the plurality of elastic portions enclose one end toward the central axis of the clamp to form a tapered hole; The fixture further includes a tapered rod, the tapered rod being inserted into the tapered hole, the tapered rod having a tapered surface, the tapered surface abutting against a side wall of the tapered hole, and the tapered rod being used to move the sector portion in a direction away from the central axis; The outer wall of the fan-shaped portion is provided with the convex portion, which protrudes from the elastic portion in the radial direction of the tensioning portion, and the concave portion is formed between adjacent convex portions and the outer side wall of the elastic portion.

14. A fixture for holding a workpiece having a central hole and a plurality of through holes arranged around the central hole, characterized in that: The fixture comprises: A support assembly, comprising a support portion for supporting the end face of the workpiece; A tensioning assembly connected to the support assembly, the tensioning assembly comprising a tensioning portion, the tensioning portion protruding from the support portion and capable of being passed through the center hole; An annular portion is sleeved on the outer wall of the tensioning portion, wherein the outer wall of the annular portion is provided with a plurality of convex portions, the plurality of convex portions are spaced apart along the circumference of the annular portion, and concave portions are formed between adjacent convex portions; In which, the tightening part can drive the convex part to move in the direction close to or away from the hole wall of the center hole. When the annular part abuts against the hole wall of the center hole, the convex part abuts against the first hole segment of the center hole. The first hole segment is the hole segment of the through hole corresponding to the center hole along the radial direction of the workpiece. The recessed part and the second hole segment of the center hole are spaced apart. The second hole segment is the hole segment between two adjacent through holes corresponding to the center hole along the radial direction of the workpiece.

15. The clamp according to claim 14, characterized in that: One of a positioning groove and a positioning protrusion is provided on one end of the ring piece portion facing the support portion, and the other of the positioning groove and the positioning protrusion is provided on one side of the support portion facing the ring piece portion.

16. A machine tool, characterized in that: Comprising the clamp according to any one of claims 1 to 15.

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