A polishing clamping device capable of clamping smooth and threaded bars

Abstract

The present invention relates to the technical field of bar processing, and aims to provide a polishing clamping device that can clamp smooth bars and threaded bars. It comprises: a travel device arranged on a machine frame, and a motor and a tailstock arranged on the travel device; a chuck structure is fixedly connected to the motor spindle, and a top is movably connected to the tailstock, and the chuck structure and the top are coaxially arranged for clamping the bar to be processed; the chuck structure includes a clamp seat and a locking nut; a replaceable clamping steel ball seat or elastic sleeve is provided in the countersunk hole at the clamping end of the clamp seat, which is used to be sleeved on the clamping section of the bar. The present invention can easily replace the elastic sleeve or the clamping steel ball seat, and uses the bearing steel ball to directly generate the clamping force, with a small force area and concentrated clamping force; the operation is simple and quick, and can improve work efficiency; the polishing quality is more uniform and stable, and the processing error is small. After long-term use, only the bearing steel ball needs to be replaced to reduce the influence of wear on the centering accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of bar processing, and in particular relates to a polishing clamping device capable of clamping smooth bars and threaded bars. Background Art

[0002] In the field of surface processing of metals and other materials, polishing refers to a process that uses mechanical (chemical or electrochemical) action to reduce the surface roughness of a workpiece, resulting in a bright, smooth surface. Polishing can be used to remove surface oxidation and burrs before machining. More commonly, it is performed after machining to achieve a satisfactory surface roughness and eliminate scratches caused by processes such as turning. Polishing can also reduce residual stress introduced during machining.

[0003] Bar stock is a common machining target. For mechanical polishing of bar stock, a suitable rotary clamping method is crucial, essential for ensuring consistent roundness and consistent machining quality. Currently, three-jaw self-centering chucks are commonly used for bar polishing. These chucks typically determine the workpiece's rotational center based on the circumference of the workpiece's clamping area. However, these chucks suffer from low clamping force and low centering accuracy. This is primarily due to the complex structure of three-jaw self-centering chucks, with numerous components and mostly clearance fits. The accumulated tolerances between these components lead to significant centering errors. With wear, the clearances between these components also increase significantly, further increasing centering errors. This can lead to uneven surface polishing, large bar stock tolerances, unstable machining quality, and incomplete scratch removal. Long-term use can cause severe wear on the front end of the jaws, which are closer to the tool. This results in only the rear end bearing force when clamping the workpiece, making clamping unstable, difficult, and potentially even causing safety hazards. Furthermore, when using a three-jaw self-centering chuck to secure a workpiece with threads, the chuck's protruding jaws can damage the threads, resulting in failure to meet machining accuracy requirements.

[0004] In summary, the existing bar polishing clamping device has problems such as easy eccentricity, unstable processing quality, and reduced reliability after wear. It is unable to clamp threaded bars and is difficult to provide reliable clamping for the subsequent polishing process. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a polishing clamping device capable of clamping smooth rods and threaded rods.

[0006] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0007] A polishing clamping device capable of clamping smooth and threaded bar stock is provided, comprising: a travel device disposed on a machine frame, and a motor and a tailstock disposed on the travel device; a chuck structure fixedly connected to a main shaft of the motor, and a centering pin movably connected to the tailstock; the chuck structure and the centering pin are coaxially arranged for clamping the bar stock to be processed;

[0008] The chuck structure includes a clamp seat and a locking nut; the main body of the clamp seat is cylindrical and includes a fixed end and a clamping end; wherein the clamping end has an external thread, and the axial countersunk hole provided on the end surface has a tapered surface; the end cap of the locking nut has a central through hole for passing the clamping section of the bar material, and the open side has an internal thread that matches the clamping end of the clamp seat;

[0009] A replaceable clamping steel ball seat or elastic sleeve is provided in the countersunk hole of the clamping end of the clamp seat, which is used to be sleeved on the clamping section of the bar;

[0010] The clamping ball seat is a single-layer annular structure with multiple radial through-holes evenly distributed along the circumference. Bearing steel balls are installed in the through-holes, and the bearing steel balls are connected to the clamping end of the clamp seat and the clamping section of the bar respectively. When the lock nut is tightened, the clamping ball seat is squeezed and produces axial displacement, causing the bearing steel balls to produce radial displacement under the constraint of the conical surface of the countersunk hole, and directly exert clamping force on the clamping section of the bar.

[0011] The elastic jacket is a single-layer annular structure with an inner surface provided with threads matching the threaded bar stock and an outer surface provided with multiple recessed spherical grooves evenly distributed along the circumference. A bearing steel ball is installed in the spherical groove, and the outer side of the bearing steel ball is connected to the clamping end of the clamp seat. When the locking nut is tightened, the elastic jacket is squeezed and produces axial displacement, causing the bearing steel ball to produce radial displacement under the constraint of the conical surface of the countersunk hole, thereby compressing the annular structure to cause it to deform, thereby generating a clamping force on the clamping section of the bar stock.

[0012] As a preferred solution of the present invention, the fixed end of the clamp seat is provided with an axial countersunk hole, and several through radial screw holes are evenly arranged along the circumference of the countersunk hole; the motor spindle is nested in the countersunk hole, and the clamp seat is fastened and installed by screws.

[0013] As a preferred solution of the present invention, the travel device includes a linear guide rail, a first slider and a second slider, the tailstock is fixedly mounted on the first slider, and the motor is fixedly mounted on the second slider.

[0014] As a preferred solution of the present invention, the radial through hole on the clamping steel ball seat is an asymmetric structure, the diameter of the outer opening is larger than the inner opening, and the inner opening is slightly smaller than the diameter of the bearing steel ball.

[0015] As a preferred solution of the present invention, there are six radial through holes on the clamping steel ball seat, which are evenly arranged in the circumferential direction at the middle of the height of the clamping steel ball seat.

[0016] As a preferred embodiment of the present invention, the elastic jacket has a plurality of evenly arranged axial slots, the slot length is smaller than the axial dimension of the elastic jacket and divides the cross section of the elastic jacket into a plurality of fan-shaped structures, the ends of the slots are circular; the fan-shaped structures are connected alternately at the top and bottom to form a whole, and the recessed spherical grooves are evenly arranged in the circumferential direction at the middle of the height of each fan-shaped structure.

[0017] As a preferred solution of the present invention, there are four axial slots and four concave spherical slots.

[0018] As a preferred embodiment of the present invention, the outer side of the bearing steel ball is exposed from the outer surface of the clamping steel ball seat or the elastic sleeve, and the height of the exposed portion is ≥0.6 mm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] When machining threaded bar stock, the clamping force is applied to the bar's clamping section using bearing steel balls and an elastic collet. The clamping section is threadedly connected to the inner surface of the elastic collet, providing ample and evenly distributed force in the circumferential direction, preventing damage to the bar's external threads. When machining smooth bar stock, the simpler clamping ball holder can be easily replaced with a ball bearing holder. This directly applies the clamping force to the bar's clamping section, minimizing the force area and concentrating the clamping force.

[0021] 2. When clamping, simply screw the bar's clamping section into the elastic sleeve in the countersunk hole or insert it into the clamping ball seat, and then tighten the lock nut. The operation is very simple and quick. Compared with the three-jaw self-centering chuck, this invention can improve work efficiency.

[0022] 3. As the lock nut is pressed in, the elastic sleeve or clamping ball seat drives the bearing steel ball into the wedge-shaped groove, increasing the radial displacement of the bearing steel ball toward the bar clamping section, generating clamping force. After polishing, simply loosen the lock nut to easily remove the bar, making disassembly convenient.

[0023] 4. The bearing steel balls symmetrically distributed along the central axis can ensure that the bar will not be eccentric during the clamping and polishing process, making the polishing quality more uniform and stable.

[0024] 5. Compared with the three-jaw self-centering chuck with complex structure, many parts and many clearance fits, this product has very few factors that can cause processing errors. After long-term use, you only need to replace the bearing steel balls to reduce the impact of wear on centering accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the overall structure of the polishing clamping device of the present invention;

[0026] Figure 2 The diagram is a structural diagram of the clamping ball seat (the upper part is an axial cross-sectional view, and the lower part is a radial cross-sectional view);

[0027] Figure 3 Schematic diagram of the structure of the elastic jacket (the left is a radial cross-sectional view, the right is a lateral axial view, and the bottom is an AA-axis axial cross-sectional view);

[0028] Figure 4 This is a schematic diagram of the clamping of smooth bar;

[0029] Figure 5 Schematic diagram of clamping of threaded bar stock.

[0030] The reference numerals in the figure are: 1 clamp seat; 2 clamping steel ball seat; 3 bearing steel ball; 4 locking nut; 5 chuck structure; 6 smooth bar; 7 center; 8 tailstock; 9 handle; 10-1 first slider; 10-2 second slider; 11 frame; 12 linear guide; 13 motor; 14 elastic sleeve; 15 threaded bar. DETAILED DESCRIPTION

[0031] The serial numbers assigned to the components in this application, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of this application, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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 to this application.

[0032] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0033] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0034] like Figure 1As shown, the polishing clamping device of the present invention, which can clamp smooth and threaded bar stock, includes a travel device provided on a frame 11 and is composed of a linear guide rail 12, a first slider 10-1, and a second slider 10-2. The tailstock 8 is fixedly mounted on the first slider 10-1, and the motor 13 is fixedly mounted on the second slider 10-2. The two sliders can be manually locked to achieve their movement and fixation along the axial direction of the bar stock on the linear guide rail 12. A handle 9 is provided at the end of the tailstock 8, and a tip 7 is movably connected to the front end of the tailstock 8. A chuck structure 5 is fixedly connected to the motor spindle. The chuck structure 5 and the tip 7 are coaxially arranged to clamp the bar stock to be processed.

[0035] The chuck structure 5 includes a clamp seat 1 and a locking nut 4. The main body of the clamp seat 1 is cylindrical, with two ends respectively comprising a fixed end and a clamping end; the fixed end is provided with an axial countersunk hole, and several through radial screw holes are evenly arranged along the circumference of the countersunk hole; the main shaft of the motor 13 is nested in the countersunk hole, and the clamp seat 1 is fastened and installed by screws. The clamping end has an external thread, and the axial countersunk hole provided on its end face has a conical surface (the radial dimension is smaller inside and larger outside). The end cover of the locking nut 4 is provided with a central through hole for passing the clamping section of the rod, and the open side is provided with an internal thread matching the clamping end of the clamp seat 1. In the countersunk hole at the clamping end of the clamp seat 1, a replaceable clamping steel ball seat 2 or an elastic sleeve 14 is provided for clamping the clamping section of the rod; the clamping steel ball seat 2 is used to clamp the smooth rod 6, and the elastic sleeve 14 is used to clamp the threaded rod 15.

[0036] The structure of the clamping ball seat 2 is as follows Figure 2 As shown, its main body is a single-layer annular structure with multiple radial through-holes distributed evenly along the circumference. The through-holes are asymmetrical, with the outer opening having a larger diameter than the inner opening, which is slightly smaller than the diameter of the bearing steel ball 3. The bearing steel ball 3 is installed in the through-hole, connecting with the clamping end of the clamp seat and the clamping section of the bar stock, respectively. When the lock nut 4 is tightened, the clamping ball seat 2 is squeezed and axially displaced, causing the bearing steel ball 3 to move radially under the constraint of the conical surface of the countersunk hole, directly exerting a clamping force on the clamping section of the bar stock. Figure 2 In the example, there are six radial through holes on the clamping steel ball seat, which are evenly arranged in the circumferential direction at the middle of the height of the clamping steel ball seat, and there are also six bearing steel balls 3 installed in conjunction with the clamping steel ball seat.

[0037] The elastic jacket 14 is a single-layered annular structure with threads on its inner surface that match the threaded bar stock 15. Its outer surface is uniformly distributed along the circumference of the bar stock, with multiple recessed spherical grooves (not through holes). Bearing steel balls 3 are installed in the spherical grooves, and the outer sides of the bearing steel balls 3 are connected to the clamping end of the clamp seat 1. When the lock nut 4 is tightened, the elastic jacket 14 is squeezed and axially displaced, causing the bearing steel balls 3 to move radially under the confinement of the conical surface of the countersunk hole. This in turn compresses the annular structure, causing it to deform and exert a clamping force on the clamping section of the bar stock.

[0038] As a specific example of an elastic jacket 14, its structure is as follows Figure 3 As shown. The main structure of the elastic jacket 14 has four evenly arranged axial slots. The slot length is smaller than the axial dimension of the elastic jacket and divides the cross section of the elastic jacket into multiple sector-shaped structures. The ends of the slots are circular. The sector-shaped structures are connected alternately with the top edge or the bottom edge to form a whole. The concave spherical grooves are evenly arranged in the middle of the height of each sector-shaped structure along the circumferential direction. The design of the axial slots can further amplify the deformation of the annular structure and generate a stronger clamping force on the clamping section of the bar. Figure 3 As shown, this embodiment has four axial slots and four concave spherical grooves, that is, there are also four bearing steel balls 3 installed in conjunction with the same.

[0039] The outer side of the bearing steel ball 3 is exposed from the outer surface of the clamping steel ball seat 2 or the elastic sleeve 14, and the height of the exposed portion is ≥0.6 mm.

[0040] A more specific embodiment description:

[0041] The fixture base 1 is constructed from high-strength bearing steel, heat-treated to achieve a hardness of 60-65 HRC at the countersunk hole at the clamping end. The fixed end of the fixture base 1 is mounted on the spindle of the motor 13 via an axial countersunk hole, which provides the rotational drive for the bar being processed. The fixed end of the fixture base 1 and the spindle of the motor 13 are fitted with a transition fit and secured with two sets of screws. The tightening of these screws in different directions can be adjusted to achieve optimal centering and alignment of the fixture base 1.

[0042] The bearing balls 3 are made of high-strength bearing steel, heat-treated to a hardness of 55-60 HRC. A corresponding number of bearing balls 3 are inserted into each through-hole of the clamping ball holder 2. The bearing balls 3 are fitted with a clearance fit, but due to the limited inner aperture, they prevent them from falling out and maintain a consistent exposed height (≥0.6mm). The clamping ball holder 2 is then installed into the countersunk hole at the clamping end of the fixture holder 1. An annular wedge groove is formed between the tapered surface of the countersunk hole and the outer surface of the clamping ball holder 2. This annular wedge groove and the through-hole together clamp and limit the bearing balls 3.

[0043] When clamping a smooth bar 6, first loosen the locking nut 4, place the clamping section of the smooth bar 6 into the clamping ball holder 2, and then tighten the locking nut 4. The clamping ball holder 2 causes the bearing balls 3 to move axially. Simultaneously, the bearing balls 3, constrained by the conical surface of the countersink, move radially inward, exerting a direct clamping force on the clamping section of the bar. The other end of the smooth bar 6 then engages the tip 7 to achieve clamping. Start the motor 13 to rotate the bar, and polish it with the polishing tool. Once finished, loosen the locking nut 4 to remove the bar.

[0044] The installation and removal procedures for threaded bar stock 15 are essentially the same as described above, with the key difference being that the clamping ball seat 2 is replaced with an elastic sleeve 14, which is threadedly connected to the threaded bar stock 15. When the lock nut 4 is tightened, the elastic sleeve 14 is squeezed and axially displaced, causing the bearing ball 3 to radially displace under the confinement of the countersunk tapered surface. This, in turn, compresses the annular structure, causing it to deform and exert a clamping force on the clamping section of the bar stock.

[0045] In order to explain the present invention more clearly, further description is given below by way of examples:

[0046] The first step is to select a clamping steel ball seat 2 or an elastic sleeve 14 according to the clamping section of the bar material to be polished; here, taking the smooth bar material 6 as an example, the clamping steel ball seat 2 is selected accordingly, and the bearing steel ball 3 is embedded in the through hole of the clamping steel ball seat 2.

[0047] The second step is to unscrew the locking nut 4 and insert the clamping section of the smooth bar 6 into the interior of the clamping steel ball seat 2. Tighten the locking nut 4 so that the bearing steel ball 3 directly clamps the clamping section of the bar.

[0048] The third step is to move the tailstock 8 and operate the handle 9 so that the tip 7 contacts the other end of the smooth bar 6. The slider 10-1 under the tailstock 8 is locked in the appropriate position to complete the clamping of the smooth bar 6. The motor 13 is started to rotate the smooth bar 6 at high speed, and the polishing tool is used to polish the bar.

[0049] Step 4: After the bar material surface reaches the grinding and polishing requirements, turn off the motor 13 to stop grinding and polishing. Remove the top 7, loosen the lock nut 4, and take out the bar material.

[0050] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. The present invention is not limited to the above examples and is subject to numerous variations. All variations that can be directly derived or imagined by a person skilled in the art from the disclosure of the present invention, as well as any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention, are intended to be included within the scope of protection of the present invention.

Claims

1. A polishing clamping device capable of clamping smooth bar stock and threaded bar stock, comprising: A traveling device provided on the frame, and a motor and a tailstock provided on the traveling device; The chuck structure is fixedly connected to the motor spindle, and the top is movably connected to the tailstock. The chuck structure and the top are coaxially arranged to clamp the bar to be processed; the feature is that: The chuck structure includes a clamp seat and a locking nut; the main body of the clamp seat is cylindrical and includes a fixed end and a clamping end; wherein the clamping end has an external thread, and the axial countersunk hole provided on the end surface has a tapered surface; the end cap of the locking nut has a central through hole for passing the clamping section of the bar material, and the open side has an internal thread that matches the clamping end of the clamp seat; A replaceable clamping steel ball seat or elastic sleeve is provided in the countersunk hole of the clamping end of the clamp seat, which is used to be sleeved on the clamping section of the bar; The clamping steel ball seat is a single-layer annular structure with multiple radial through holes evenly distributed along the circumference; bearing steel balls are installed in the through holes, and the bearing steel balls are respectively connected to the clamping end of the clamp seat and the clamping section of the bar stock; when the locking nut is tightened, the clamping steel ball seat is squeezed and axially displaced, causing the bearing steel balls to radially displace under the constraint of the conical surface of the countersunk hole, and directly exerting a clamping force on the clamping section of the bar stock; the radial through holes on the clamping steel ball seat are asymmetric in structure, with the diameter of the outer opening being larger than the inner opening, and the inner opening being slightly smaller than the diameter of the bearing steel balls; The elastic jacket is a single-layer annular structure, the inner surface of which is provided with a thread matching the threaded rod, and the outer surface is evenly distributed with a plurality of recessed spherical grooves along the circumference; a bearing steel ball is installed in the spherical groove, and the outer side of the bearing steel ball is connected to the clamping end of the clamp seat; when the locking nut is tightened, the elastic jacket is squeezed and produces axial displacement, causing the bearing steel ball to produce radial displacement under the constraint of the conical surface of the countersunk hole, thereby compressing the annular structure to deform it, and generating a clamping force on the clamping section of the rod; the elastic jacket has a plurality of evenly arranged axial slots, the slot length is smaller than the axial dimension of the elastic jacket and divides the cross section of the elastic jacket into a plurality of fan-shaped structures, the ends of the slots are circular; the fan-shaped structures are connected alternately at the top and bottom to form a whole, and the recessed spherical grooves are evenly arranged in the middle of the height of each fan-shaped structure along the circumferential direction.

2. The polishing clamping device according to claim 1, characterized in that: The fixed end of the clamp seat is provided with an axial countersunk hole, and a plurality of through radial screw holes are evenly arranged along the circumference of the countersunk hole; the motor spindle is nested in the countersunk hole, and the clamp seat is fastened and installed by screws.

3. The polishing clamping device according to claim 1, characterized in that: The traveling device includes a linear guide rail, a first slider and a second slider. The tailstock is fixedly mounted on the first slider, and the motor is fixedly mounted on the second slider.

4. The polishing clamping device according to claim 1, characterized in that: There are six radial through holes on the clamping steel ball seat, which are evenly arranged in the middle of the height of the clamping steel ball seat along the circumferential direction.

5. The polishing clamping device according to claim 1, characterized in that: There are four axial slots and four concave spherical slots.

6. The polishing clamping device according to claim 1, characterized in that: The outer side of the bearing steel ball is exposed from the outer surface of the clamping steel ball seat or the elastic sleeve, and the height of the exposed part is ≥0.6mm.

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