Off-center mandrel and machine tool tailstock

Abstract

The utility model discloses an eccentric core shaft, including the core shaft body, be equipped with the core shaft hole on the core shaft body, the axis of core shaft hole and the axis of core shaft body eccentricity correspond. The one end of core shaft body is equipped with the locating ring part to the workpiece direction, and is equipped with the fastening hole no. 1 on the locating ring part. Still provide a kind of lathe tailstock, including tailstock body, be equipped with core hole on tailstock body, the eccentric core shaft as above is equipped in the core hole, the core shaft hole is rotatably connected with the centre body through bearing, tailstock body is equipped with the fastening hole no. 2 corresponding with the fastening hole no. 1, and the locating ring part is fastened and connected with tailstock body by fastener. The eccentric position of core shaft hole is adjusted by rotating core shaft body, can realize the butt joint with the spindle axis, only needs a small amount of scraping operation, significantly improves assembly efficiency, reduces labor intensity.

Description

Technical Field

[0001] This utility model relates to the field of machine tool tailstock technology, and in particular to an eccentric mandrel and a machine tool tailstock with the eccentric mandrel. Background Technology

[0002] Traditional machine tool tailstocks are typically fixed-axis structures, meaning the axis of the spindle corresponds coaxially with the mounting holes on the tailstock body. They maintain concentricity with the chuck and other fixtures at the machine tool spindle end, jointly clamping long shaft-type workpieces for machining. Ideally, the spindle center and tailstock center should be perfectly concentric, with all related components such as the spindle, mounting holes, chuck, or center body corresponding concentrically.

[0003] In practice, due to the workpiece's center of gravity and the different forces applied to the chuck and tailstock ends, the center height of the tailstock end is slightly higher than that of the spindle end. During high-speed rotation, if high-precision coaxiality cannot be guaranteed, not only will there be safety hazards, but the machined workpiece will also have errors exceeding the preset values. Therefore, during installation, the alignment error between the tailstock and the spindle center must be very small; the vertical concentricity runout must be within 0.06mm, and the horizontal concentricity runout must be within 0.04mm. To ensure these high precision requirements, manual scraping is used to achieve this.

[0004] However, the manual scraping process requires a very high level of skill from the assembly workers. Moreover, if the tailstock is over-scraped during the scraping process, the fixed headstock must be disassembled and scraped again. This repeated scraping process is very tedious and irreversible, consuming a lot of time and is laborious and inconvenient to operate. Utility Model Content

[0005] The purpose of this invention is to provide an eccentric mandrel and a machine tool tailstock with the eccentric mandrel, to solve the problems mentioned in the background art. It can solve the problems of high scraping difficulty, low efficiency, and poor precision, and can significantly reduce the labor intensity of workers in scraping.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0007] On the one hand, an eccentric mandrel is provided, including a mandrel body, wherein the mandrel body is provided with a mandrel hole;

[0008] The axis of the mandrel hole is eccentrically aligned with the axis of the mandrel body.

[0009] Preferably, the mandrel body has a positioning ring portion that protrudes in the circumferential direction at one end near the workpiece, and the positioning ring portion has a plurality of fastening holes.

[0010] Preferably, the mandrel hole extends through the axial direction of the mandrel body.

[0011] Preferably, the diameter of the mandrel hole gradually decreases from the end closer to the workpiece to the end farther away from the workpiece.

[0012] On the other hand, a machine tool tailstock is also provided, including a tailstock body connected to a feed mechanism, wherein the tailstock body is provided with a core hole;

[0013] The core hole is provided with an eccentric mandrel as described above, and the mandrel hole is rotatably connected to the center body through a bearing;

[0014] The tailstock body is provided with a second fastening hole corresponding to the first fastening hole, and the positioning ring is fastened to the tailstock body by fasteners.

[0015] Preferably, an auxiliary ring is provided between the positioning ring and the tailstock body, which is sleeved on the outer periphery of the mandrel body. The auxiliary ring is provided with a plurality of fastening holes three corresponding to the fastening holes two.

[0016] Preferably, the auxiliary ring is further provided with a plurality of fastening holes four corresponding to the fastening hole one.

[0017] Preferably, the fastener is a fastening bolt.

[0018] Due to the adoption of the above technical solution, the beneficial effects of this utility model are as follows:

[0019] 1. By rotating the mandrel body to adjust the eccentric position of the mandrel hole, it is possible to align with the spindle axis. Only a small amount of scraping is required, which significantly improves assembly efficiency and reduces labor intensity.

[0020] 2. The fasteners are used to achieve the fixed connection, which is simple, strong and reliable, ensuring the rigidity of the clamping and suitable for heavy cutting conditions.

[0021] 3. It has a compact structure, strong compatibility, low cost of retrofitting existing machine tools, and obvious cost advantages. Attached Figure Description

[0022] Figure 1 This is a schematic front sectional view of the eccentric mandrel in this utility model;

[0023] Figure 2 A three-dimensional disassembly of the machine tool tailstock structure in this utility model. Figure 1 ;

[0024] Figure 3 This is a schematic front view of the structure of the machine tool tailstock in this utility model. Figure 1 ;

[0025] Figure 4 for Figure 3 Schematic diagram of the AA-direction structure;

[0026] Figure 5 This is a schematic front view of the structure of the machine tool tailstock in this utility model. Figure 2 ;

[0027] Figure 6 for Figure 5 Schematic diagram of the BB-oriented structure;

[0028] Figure 7 This is a schematic front view of the structure of the machine tool tailstock in this utility model. Figure 3 ;

[0029] Figure 8 This is a schematic diagram showing the comparison of the center points between the mandrel hole and the main shaft in this utility model. Figure 1 ;

[0030] Figure 9 This is a schematic diagram showing the comparison of the center points between the mandrel hole and the main shaft in this utility model. Figure 2 ;

[0031] Figure 10 This is a schematic diagram showing the comparison of the center points between the mandrel hole and the main shaft in this utility model. Figure 3 ;

[0032] Figure 11 This is a schematic diagram showing the comparison of the center points between the mandrel hole and the main shaft in this utility model. Figure 4 ;

[0033] Figure 12 This is a schematic diagram showing the comparison of the center points between the mandrel hole and the main shaft in this utility model. Figure 5 ;

[0034] Figure 13 This is a schematic diagram showing the comparison of the center points between the mandrel hole and the main shaft in this utility model. Figure 6 ;

[0035] Figure 14 A three-dimensional disassembly of the machine tool tailstock structure in this utility model. Figure 2 .

[0036] In the picture:

[0037] 100, mandrel body 101, mandrel hole 102, positioning ring 1021, fastening hole one;

[0038] 200, Top-tier style;

[0039] 300, Tailstock body 301, Core hole 302, Fastening hole two;

[0040] 4. Spindle;

[0041] 500, auxiliary ring 501, fastening hole three 502, fastening hole four. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this utility model clearer, the following is a summary description. Figure 1 To be continued Figure 14 The present invention will be further described in detail with reference to embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the scope of the present invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the present invention.

[0043] Example 1

[0044] This embodiment discloses an eccentric mandrel, which, compared with the traditional mandrel, improves the central mandrel hole to be eccentric. The eccentric angle of the mandrel hole is achieved by rotating the mandrel body, thereby adjusting the concentricity of the tip body and the spindle, saving a lot of scraping operations and improving efficiency.

[0045] refer to Figure 1 As shown, specifically, it includes a mandrel body 100, on which a mandrel hole 101 is provided; the axis of the mandrel hole 101 is eccentrically aligned with the axis of the mandrel body 100. The mandrel hole 101 extends through the axial direction of the mandrel body 100, thus facilitating the removal of the center from the rear. Of course, it can also be a non-through structure.

[0046] In traditional designs, the spindle hole 101 and the spindle body 100 are coaxial and concentric. When adjusting the concentricity of the tailstock with this structure with the spindle, it is necessary to disassemble the machine and perform scraping. This involves many parts, a large area, and low efficiency, consuming a lot of time. Moreover, if the scraping is excessive, the headstock needs to be removed for scraping to compensate for the discrepancy, making it even more cumbersome and inconvenient.

[0047] By setting the mandrel hole 101 to be eccentric, the center of the mandrel hole 101 can be adjusted by selecting the mandrel body 100. In use, by adding an adjustment feed mechanism, the concentricity can be adjusted quickly and conveniently.

[0048] In this embodiment, to facilitate fixing the rotated mandrel 100 to the tailstock 300, a positioning ring 102 protruding in the circumferential direction is provided at one end of the mandrel 100 near the workpiece. The positioning ring 102 has several fastening holes 1021, which are used to fasten the two together with bolts. These fastening holes 1021 need to be through holes for the bolts to pass through.

[0049] To improve the stability of the center body during high-speed rotation, the diameter of the mandrel hole 101 gradually decreases from the end closer to the workpiece to the end farther away from the workpiece. That is, the portion of the center body that extends into the mandrel hole 101 has a conical structure, although it can also be a cylindrical structure, consistent with the structure of a traditional mandrel hole 101.

[0050] Example 2

[0051] The similarities between this embodiment and Embodiment 1 will not be repeated here.

[0052] This application also provides a machine tool tailstock, including a tailstock body 300 connected to a feed mechanism, wherein the tailstock body 300 is provided with a core hole 301;

[0053] The aforementioned eccentric mandrel is housed within the mandrel hole 301. After connection, the mandrel body 100 can rotate axially within the mandrel hole 301. It should be noted that the central axis of rotation of the mandrel body 100 is coaxial with the central axis of the mandrel hole 301. The mandrel hole 101 is rotatably connected to the center body 200 via a bearing. Since the position and assembly relationship of the bearing seat remain unchanged and are conventional techniques, they are not shown in the figure to more clearly illustrate the core structure of the product improvement.

[0054] The tailstock body 300 is provided with a second fastening hole 302 corresponding to the first fastening hole 1021. The two are fastened together by bolts, that is, the positioning ring 102 is fastened to the tailstock body 300. This second fastening hole 302 is a blind hole.

[0055] Reference Figures 2 to 13 When adjusting concentricity, the specific adjustment method is as follows: From Figure 4 As can be seen, the eccentricity angle of the mandrel hole 101 is downward, that is, the wall thickness of the upper half of the mandrel body 100 is large, and the wall thickness of the lower half is small. Figure 6 The structure shown is Figure 4 If the structure shown is reversed, the eccentricity angle of the mandrel hole 101 is upward. Figure 7 The eccentricity angle of the mandrel hole 101 shown is the lower right corner in the direction shown in the figure.

[0056] Figure 8 The content shown is a vertical comparison of the difference a1 between the height of the center (or axis) of the core hole 301 and the height of the center (or axis) of the spindle 4. Figure 9 To ensure that the center of the core hole 301 is perpendicularly aligned with the center of the spindle 4 in the horizontal direction without offset, this is a method of eccentric alignment.

[0057] Figure 10 The content shown is a vertical comparison of the difference a3 between the height of the center (or axis) of the core hole 301 and the height of the center (or axis) of the spindle 4. Figure 11 The center of the core hole 301 in the horizontal direction is offset from the center of the spindle 4, with a difference of b3. This is another way of corresponding eccentricity.

[0058] Figure 12 The content shown is a vertical comparison of the difference a2 between the height of the center (or axis) of the core hole 301 and the height of the center (or axis) of the spindle 4. Figure 13 The center of the core hole 301 in the horizontal direction is offset from the center of the spindle 4, with a difference of b2. This is another way of corresponding eccentricity.

[0059] Example 3

[0060] The purpose of this embodiment is to improve the convenience of replacement and adjustment.

[0061] refer to Figure 14 Specifically, an auxiliary ring 500 is provided between the positioning ring 102 and the tailstock 300, sleeved on the outer periphery of the mandrel 100. The auxiliary ring 500 has several fastening holes 501 corresponding to the second fastening hole 302, also for fastening the two together. These fastening holes 501 are through holes. When using this structure, it is important to ensure that the bolt end does not protrude beyond the fastening hole 501 after it has been inserted, to avoid affecting the connection with the positioning ring 102. That is, the bolt end must be concealed within the fastening hole 501.

[0062] In addition, the auxiliary ring 500 is provided with several fastening holes 502 corresponding to the fastening hole 1021. These fastening holes 502 can be blind holes or through holes. The fastening holes 502 in this structure are used to achieve a fastening connection with the positioning ring 102, so blind holes or through holes are acceptable, as long as they do not affect the fastening connection with the tailstock 300.

[0063] This embodiment allows for adaptation to different eccentric mandrels simply by disassembling and replacing different auxiliary rings 500. Because different workpieces require different center bodies 200, and different center bodies 200 correspond to different eccentric mandrels, different tailstock bodies are also needed for ease of operation and to save significant scraping time. This results in workpieces requiring different tailstock bodies, mandrel bodies, and other accessories, leading to numerous models and high costs.

[0064] With this embodiment, a single tailstock body 300 can accommodate various types of mandrel bodies 100. The fourth fastening hole 502 on the auxiliary ring 500 corresponds to the first fastening hole 1021, and its purpose is to achieve a fixed connection with the tailstock body. The third fastening hole 501 is for a fixed connection with the positioning ring 102. The number and position of the third fastening hole 501 correspond to the first fastening hole 1021 to ensure their accuracy. When machining workpieces of different models and specifications, only the different auxiliary rings 500 need to be replaced; the entire tailstock body 300 does not need to be replaced, saving significant disassembly, assembly, and scraping time, reducing the need for additional parts, and substantially lowering costs.

[0065] Due to the adoption of the above technical solution, the beneficial effects of this utility model are as follows:

[0066] 1. By rotating the mandrel body to adjust the eccentric position of the mandrel hole, it is possible to align with the spindle axis. Only a small amount of scraping is required, which significantly improves assembly efficiency and reduces labor intensity.

[0067] 2. The fasteners are used to achieve the fixed connection, which is simple, strong and reliable, ensuring the rigidity of the clamping and suitable for heavy cutting conditions.

[0068] 3. It has a compact structure, strong compatibility, low cost of retrofitting existing machine tools, and obvious cost advantages.

[0069] like Figure 1 As shown, this structure consists of three parts: the tailstock body, the eccentric tailstock spindle, and the movable center. After the headstock is installed, the tailstock body is fixed on the machine tool linear guide. The eccentric spindle is then inserted into the pre-drilled through hole in the tailstock body. The concentricity runout of the tailstock center in two directions is adjusted by rotating the eccentric spindle.

[0070] like Figure 3 As shown, the central axis of the spindle is perpendicular to the central axis of the tailstock by a1, and horizontally it is collinear with the central axis of the tailstock. Therefore, we conclude that the central axis of the spindle is slightly higher than the center line of the tailstock. We only need to rotate the eccentric mandrel of the tailstock to make the central hole of the eccentric mandrel of the tailstock rotate to the upper position to achieve collinearity with the central axis of the spindle, and then fix it through the fixing screw hole.

[0071] like Figure 4 As shown, the vertical direction of the spindle center axis is offset by a2 from the tailstock center axis, and the horizontal direction is offset by b2 from the tailstock center axis. Therefore, we need to rotate the tailstock eccentric mandrel to the lower left position to achieve collinearity with the spindle center axis, and then fix it through the fixing screw hole.

[0072] like Figure 5As shown, the vertical direction of the spindle center axis is offset by a3 from the tailstock center axis, and the horizontal direction is offset by b3 from the tailstock center axis. Therefore, we need to select and install a tailstock eccentric mandrel to rotate the tailstock eccentric mandrel to the lower right position to achieve collinearity with the spindle center axis, and then fix it through the fixing screw hole.

[0073] It should be emphasized that the above only describes the structural features of this application. In actual use, it is also necessary to use appropriate measurement methods to measure the concentricity difference.

[0074] The specific steps are as follows:

[0075] Two standard rods (of the same diameter) and a dial indicator are needed for measurement. Standard rod one is connected to the machine tool spindle, and standard rod two is connected to the mandrel hole of the mandrel body, so that the two standard rods are in a corresponding state with their ends facing each other. After connecting the dial indicator to the slide, it slides linearly between the two standard rods. The measuring tip of the dial indicator is in contact with one of the standard rods and moves towards the other. Because the two standard rods are not perfectly concentric, the measuring tip of the dial indicator will fluctuate as it passes the two standard rods due to the lack of concentricity, thus measuring the difference in concentricity.

[0076] After measuring and calculating the difference, the mandrel body is rotated to adjust the eccentric position of the mandrel hole, thereby continuously correcting the axis of standard rod two. Ultimately, through continuous adjustment of the eccentric angle of the mandrel hole, standard rod two and standard rod one achieve concentric alignment. Of course, there will still be some error, but it will be within the preset value.

[0077] Then, while keeping the mandrel body 100 in place, mark the position of the second fastening hole 302 on the tailstock body 300, corresponding to the first fastening hole 1021. Drill the second fastening hole 302 at this position, and connect the two holes with a fastening bolt to achieve the fixed connection between the mandrel body and the tailstock body. It should be noted that there may be a slight error between the two holes, which can be adjusted by tightening the bolt by 2 or 3 threads.

[0078] Finally, simply remove the standard rod and replace it with the tip.

[0079] In practice, a simple scraping process is performed, leaving a certain margin to prevent over-scraping. This margin is very small, and the scraping time is short. Furthermore, compensation is made by adjusting the tightness of the bolts (e.g., the number of threads tightened). The bolts are not fully tightened initially; after adjusting the position of the mandrel, the bolts are then tightened to the appropriate number of threads.

[0080] By adopting this structure and measurement method, the scraping process can be significantly reduced, requiring only a small amount of appropriate scraping, greatly reducing the scraping burden on workers and the time spent on scraping. The concentricity of the center body can also be guaranteed, ultimately ensuring that the error of the workpiece after processing is within a reasonable range, thus guaranteeing the product's precision requirements.

[0081] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An eccentric mandrel, comprising a mandrel body (100) having a mandrel hole (101) thereon. Its features are: The axis of the mandrel hole (101) is eccentrically aligned with the axis of the mandrel body (100).

2. The eccentric mandrel according to claim 1, characterized in that: The mandrel body (100) has a positioning ring (102) that protrudes in the circumferential direction at one end near the workpiece, and the positioning ring (102) has a plurality of fastening holes (1021).

3. The eccentric mandrel according to claim 2, characterized in that: The mandrel hole (101) extends through the axial direction of the mandrel body (100).

4. The eccentric mandrel according to claim 1, characterized in that: The diameter of the mandrel hole (101) gradually decreases from the end closer to the workpiece to the end farther away from the workpiece.

5. A machine tool tailstock, comprising a tailstock body (300) connected to a feed mechanism, wherein the tailstock body (300) is provided with a core hole (301). Its features are: The core hole (301) is provided with an eccentric mandrel as described in any one of claims 1 to 4, and the mandrel hole (101) is rotatably connected to the center body (200) through a bearing; The tailstock body (300) is provided with a second fastening hole (302) corresponding to the first fastening hole (1021), and the positioning ring (102) is fastened to the tailstock body (300) by fasteners.

6. The machine tool tailstock according to claim 5, characterized in that: An auxiliary ring (500) is also provided between the positioning ring (102) and the tailstock (300) and sleeved on the outer periphery of the mandrel body (100). The auxiliary ring (500) is provided with a plurality of fastening holes three (501) corresponding to the fastening hole two (302); the auxiliary ring (500) is also provided with a plurality of fastening holes four (502) corresponding to the fastening hole one (1021).

7. The machine tool tailstock according to claim 6, characterized in that: The fastener is a fastening bolt.

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