High-precision length positioning device for secondary clamping of numerically controlled lathe

Abstract

The utility model discloses a numerical control lathe secondary clamping high-precision length locating device which comprises a clamping jaw and a locating tool, the clamping jaw is configured to be capable of being installed on the end face of a three-jaw hydraulic chuck, the locating tool is configured to be capable of being installed in a center hole of the three-jaw hydraulic chuck, the clamping jaw comprises a clamping part, the clamping part comprises a rear section and a front section, and the rear section is provided with a clamping groove. The rear section extends into a center hole of the three-jaw hydraulic chuck from front to back in the direction parallel to a center shaft of the three-jaw hydraulic chuck, the front section extends outwards in the radial direction of the three-jaw hydraulic chuck to form a clearance, the positioning tool comprises a positioning tool body, and the positioning tool body is provided with a positioning face; the positioning face is parallel to the end face of the three-jaw hydraulic chuck and located in a center hole of the three-jaw hydraulic chuck, an air leakage hole is formed in the positioning face in a penetrating mode, the positioning face is configured to be capable of making contact with the end face of a product workpiece, and air of the air leakage hole is communicated to a compressed air source.

Description

Technical Field

[0001] This utility model relates to the field of machining technology, and in particular to a high-precision length positioning device for secondary clamping of CNC lathes. Background Technology

[0002] With the continuous development of industrial technology, CNC machine tools are increasingly widely used in industrial equipment, aerospace, transportation (such as airplanes, trains, and automobiles), and life science instruments. However, not all products can be processed in one go during CNC machine tool processing; many require multiple processes. During the secondary clamping process, whether in pre-positioning or post-positioning, improper clamping frequently occurs, leading to workpiece length dimensional deviations and scrapping. This is especially true for products with high length requirements, where the tolerance is only 0.03 mm, resulting in a higher scrap rate due to improper clamping. For workpieces exceeding 100 m in length, the positioning position is located inside the machine tool chuck, making it difficult to visually confirm proper clamping and the presence of metal filings or debris on the positioning fixture surface. In the machining process of mechanical products, secondary clamping makes it difficult to control the length dimensions of high-precision products, thus affecting their performance. Especially for new employees, inadequate clamping methods or techniques can not only lead to product scrapping but may even cause machine collisions.

[0003] Therefore, those skilled in the art are dedicated to developing a high-precision length positioning device for secondary clamping of CNC lathes. This device is designed with a special chuck and equipped with a modified airtightness detection device to ensure the stability of the product length during secondary clamping, thereby improving machining accuracy and reliability. Utility Model Content

[0004] In view of the above-mentioned defects in the prior art, the technical problem to be solved by this utility model is how to solve the problem of unstable positioning of the secondary clamping length of the product and the difficulty in controlling the length tolerance.

[0005] To achieve the above objectives, this utility model provides a high-precision length positioning device for secondary clamping of a CNC lathe, including a jaw and a positioning fixture. The jaw is configured to be mounted on the end face of a three-jaw hydraulic chuck, and the positioning fixture is configured to be mounted inside the central hole of the three-jaw hydraulic chuck. The jaw includes an engaging portion, which includes a rear section and a front section. The rear section extends from front to back into the central hole of the three-jaw hydraulic chuck in a direction parallel to the central axis of the three-jaw hydraulic chuck, and the front section extends radially outward along the three-jaw hydraulic chuck to form a clearance. The positioning fixture includes a positioning fixture body, which has a positioning surface. The positioning surface is parallel to the end face of the three-jaw hydraulic chuck and located inside the central hole of the three-jaw hydraulic chuck. A vent hole is provided through the positioning surface, and the positioning surface is configured to contact the end face of the workpiece. The vent hole is connected to a compressed air source.

[0006] Furthermore, the engagement surface of the rear section facing the product workpiece is an arc surface.

[0007] Furthermore, the engaging surface of the front section facing the product workpiece is an arc surface.

[0008] Furthermore, the inner circle dimension of the rear engagement surface matches the outer circle dimension of the end of the product workpiece.

[0009] Furthermore, the inner circle dimension of the front engagement surface is designed to avoid the outer circle dimension of the corresponding position of the product workpiece after it is positioned by the positioning fixture.

[0010] Furthermore, the vent hole is designed to be in contact with the end face of the product workpiece.

[0011] Furthermore, the vent hole is designed to avoid the central inner hole of the product workpiece.

[0012] Furthermore, the positioning fixture also includes a gas pipeline, a connecting flange, and a connector. One end of the gas pipeline is connected to the vent hole at the rear end of the positioning fixture body, and the other end of the gas pipeline is connected to the connector through the connecting flange.

[0013] Furthermore, the gas pipeline is a long, thin straight pipe located inside the spindle of the CNC lathe.

[0014] Furthermore, the connector is connected to the gas distributor of the CNC lathe.

[0015] The beneficial effects of this utility model are: by using this utility model, the problems of unstable length and small product tolerance leading to low pass rate during secondary clamping of CNC lathes can be effectively solved, and the collision accident caused by improper workpiece clamping can be avoided, thus significantly improving processing quality and production efficiency.

[0016] The following will further explain the concept, specific structure and technical effects of this utility model in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of this utility model. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a chuck jaw in the prior art;

[0018] Figure 2 This is a schematic diagram of the chuck jaws of a preferred embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the claw structure of a preferred embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the structure of a product workpiece according to a preferred embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the processing of a product workpiece according to a preferred embodiment of the present invention;

[0022] Figure 6 yes Figure 5 A sectional view along the AA direction.

[0023] Among them, 10-three-jaw hydraulic chuck, 20-jaw, 21-clamping part, 22-rear section, 23-front section, 30-positioning fixture, 31-positioning fixture body, 32-gas pipeline, 33-connecting flange, 34-connector, 40-product workpiece. Detailed Implementation

[0024] The preferred embodiments of this utility model are described below with reference to the accompanying drawings to make the technical content clearer and easier to understand. This utility model can be embodied in many different embodiments, and the scope of protection of this utility model is not limited to the embodiments mentioned herein.

[0025] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and this invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0026] This utility model provides a high-precision length positioning device for secondary clamping of CNC lathes. The device consists of two main parts: one is the modification of the chuck jaws, and the other is the airtightness detection device added to the positioning device.

[0027] 1. Chuck and jaw modification

[0028] like Figure 1 As shown, most existing CNC lathes use a three-jaw hydraulic chuck 10. Due to the clamping principle of the three-jaw hydraulic chuck 10, when clamping the workpiece 40 ( Figure 4 As shown, the clamping forces between the jaw 20 and the workpiece 40 interact, causing the front section of the jaw 20 to bulge outwards, which in turn causes the workpiece 40 to move forward. The degree of deformation of the front section of the jaw 20 is related to the thickness of the jaw 20 and its distance from the end face of the three-jaw hydraulic chuck 10. The thicker the jaw 20 and the greater the distance from the end face of the three-jaw hydraulic chuck 10, the more significant the deformation of the front section.

[0029] like Figure 2 , Figure 3 As shown, to prevent the workpiece 40 from shifting forward during clamping, the present invention modifies the jaw 20. Specifically, the jaw 20 is extended inside the three-jaw hydraulic chuck 10, and the outer end of the front section of the jaw 20 is made open, so that the outer end does not need to be clamped during clamping, thus avoiding the phenomenon of the outer end expanding and preventing the workpiece 40 from shifting outward.

[0030] 2. Add airtightness testing to the end face positioning fixture.

[0031] When the end face of the product workpiece 40 is not in complete contact with the positioning surface of the positioning fixture 30, air leakage will occur through the vent hole on the positioning fixture 30. The larger the gap between the end face of the product workpiece 40 and the positioning surface of the positioning fixture 30, the greater the amount of air leakage. Therefore, a specific set value for the amount of air leakage through the vent hole is designed so that when the gap between the end face of the product workpiece 40 and the positioning surface of the positioning fixture 30 exceeds 0.01 to 0.02 mm, the amount of air leakage is set to a certain value. Specifically: when the amount of air leakage is lower than the set value, it indicates that the gap between the end face of the product workpiece 40 and the positioning surface of the positioning fixture 30 is less than 0.01 mm; when the amount of air leakage exceeds the set value, it indicates that the gap between the end face of the product workpiece 40 and the positioning surface of the positioning fixture 30 is greater than 0.02 mm.

[0032] If the gap between the end face of the workpiece 40 and the positioning surface of the positioning fixture 30 is greater than 0.02 mm, the CNC lathe spindle will not start and will issue an alarm, indicating to the operator that the workpiece 40 is not properly clamped and needs to be re-clamped. This design effectively avoids the problem of the workpiece 40's length dimension exceeding tolerance due to improper clamping, ensuring that the product meets design requirements, preventing product scrap due to improper clamping, and improving the efficiency and quality of the machining industry. Example

[0033] This embodiment solves the above-mentioned technical problems through the following technical solution:

[0034] A specialized chuck jaw was designed, improving and optimizing the traditional chuck jaw by extending its rear section to penetrate deeper into the chuck. This prevents the jaw from generating a reverse thrust during clamping, which could cause the workpiece to move outward. Simultaneously, an airtightness detection device was installed to effectively prevent machining scrap caused by unstable workpiece clamping length.

[0035] like Figure 2 As shown, the direction from which the end face of the CNC lathe facing the three-jaw hydraulic chuck 10 points inward is the rearward direction, and the direction opposite to the rearward direction is the forward direction.

[0036] like Figure 2-6 As shown, this embodiment provides a high-precision length positioning device for secondary clamping of a CNC lathe, including a jaw 20 and a positioning fixture 30. The jaw 20 is adapted to be installed on the end face of a three-jaw hydraulic chuck 10, and the positioning fixture 30 is adapted to be installed inside the central hole of the three-jaw hydraulic chuck 10. The jaw 20 includes an engaging portion 21, which includes a rear section 22 and a front section 23. The rear section 22 extends from front to back into the central hole of the three-jaw hydraulic chuck 10 in a direction parallel to the central axis L of the three-jaw hydraulic chuck 10, thereby clamping the workpiece 40 and ensuring that the workpiece 40 is not squeezed out. The front section 23 extends radially outward along the three-jaw hydraulic chuck 10 to form a clearance, thereby preventing clearance and limiting the position. The positioning fixture 30 includes a positioning fixture body 31, which has a positioning surface. The positioning surface is parallel to the end face of the three-jaw hydraulic chuck 10 and is located inside the center hole of the three-jaw hydraulic chuck 10. A vent hole is provided through the positioning surface. The positioning surface is configured to contact the end face of the product workpiece 40. The gas in the vent hole is connected to a compressed air source.

[0037] The engagement surface of the rear section 22 facing the product workpiece 40 is an arc surface.

[0038] The engagement surface of the outer segment 23 facing the product workpiece 40 is an arc surface.

[0039] The inner circle dimension of the mating surface of the rear section 22 matches the outer circle dimension of the end of the product workpiece 40.

[0040] The inner circle dimension of the front 23 mating surface is designed to avoid the outer circle dimension of the corresponding position after the product workpiece 40 and the positioning fixture 30 are positioned.

[0041] The vent hole is designed to contact the end face of the product workpiece 40.

[0042] The vent hole is designed to avoid the center inner hole of the product workpiece 40.

[0043] The positioning fixture 30 also includes a gas pipeline 32, a connecting flange 33, and a connector 44. One end of the gas pipeline 32 is connected to a vent hole inside the positioning fixture body 31, and the other end of the gas pipeline 32 is connected to the connector 34 through the connecting flange 33.

[0044] Gas line 32 is a long, thin straight tube located inside the spindle of the CNC lathe.

[0045] Connector 34 connects the gas to the gas distributor of the CNC lathe.

[0046] for Figure 4 The workpiece shown has a length tolerance of 0.04 mm and a total length of 175.3 mm. Due to the product's characteristics, it requires multiple processing steps. In the third process, the outer diameter of the workpiece needs to be clamped, and the inner hole on the right end and the end face length need to be machined. The specific processing method is as follows:

[0047] Step 1: Fabricate the airtightness testing channel pipeline within the positioning fixture: Connect the airtightness testing channel pipeline to the machine tool spindle, such as... Figure 5 , Figure 6 As shown.

[0048] Step 2: Connect the positioning fixture body to the three-jaw hydraulic chuck: Ensure that the vent hole of the positioning fixture body is in contact with the end face of the workpiece, avoiding the 5.0 mm inner hole position at the center of the workpiece. Figure 6 As shown.

[0049] Step 3: Make special claws, such as Figure 3 As shown.

[0050] Step 4: Install and fine-tune the chuck jaws: After installing the special chuck jaws onto the three-jaw hydraulic chuck, perform fine-tuning to ensure that the jaw runout is within 0.01 mm. Ensure the inner diameter of the jaws matches the outer diameter of the workpiece, and perform clearance treatment on the outer ends of the jaws. Figure 2 As shown.

[0051] Step 5: Place and clamp the product workpiece: Place the product workpiece into the chuck jaws, perform rear-end positioning, and clamp it.

[0052] Step 6: Adjust the airtightness detection parameters: Set the spindle to not start when the gap between the end face of the product workpiece and the positioning surface of the positioning fixture body exceeds 0.02 mm, in order to prevent the dimensions of the product workpiece from exceeding the tolerance after processing.

[0053] Step 7: Start the CNC lathe: Press the start button on the CNC lathe. If the spindle fails to start, it indicates that the workpiece is not properly clamped or there are foreign objects on the end face, and it needs to be re-clamped and processed.

[0054] In summary, the main features of this utility model are: a specially designed chuck to avoid the back thrust generated during clamping, preventing the workpiece from moving outwards; and the addition of a modified airtightness detection device to ensure the length stability of the product during secondary clamping.

[0055] This invention effectively solves the problems of unstable length and low product tolerance leading to low pass rate during secondary clamping of CNC lathes, while avoiding tool collision accidents caused by improper clamping of the product workpiece, thus significantly improving processing quality and production efficiency.

[0056] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A high-precision length positioning device for secondary clamping of a CNC lathe, characterized in that, The device includes a jaw and a positioning fixture. The jaw is configured to be mounted on the end face of a three-jaw hydraulic chuck, and the positioning fixture is configured to be mounted inside the central hole of the three-jaw hydraulic chuck. The jaw includes an engaging portion comprising a rear section and a front section. The rear section extends from front to back into the central hole of the three-jaw hydraulic chuck in a direction parallel to the central axis of the three-jaw hydraulic chuck, and the front section extends radially outward along the three-jaw hydraulic chuck to form a clearance. The positioning fixture includes a positioning fixture body with a positioning surface parallel to the end face of the three-jaw hydraulic chuck and located inside the central hole of the three-jaw hydraulic chuck. A vent hole is provided through the positioning surface, and the positioning surface is configured to contact the end face of the workpiece. The vent hole is connected to a compressed air source.

2. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 1, characterized in that, The engagement surface of the rear section facing the product workpiece is an arc surface.

3. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 1, characterized in that, The engagement surface of the front section facing the product workpiece is an arc surface.

4. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 2, characterized in that, The inner circle dimension of the rear engagement surface matches the outer circle dimension of the end of the product workpiece.

5. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 3, characterized in that, The inner circle dimension of the front engagement surface is designed to avoid the outer circle dimension of the corresponding position of the product workpiece after it is positioned by the positioning fixture.

6. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 1, characterized in that, The vent hole is designed to be in contact with the end face of the product workpiece.

7. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 6, characterized in that, The location of the vent hole is designed to avoid the center inner hole of the product workpiece.

8. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 1, characterized in that, The positioning fixture also includes a gas pipeline, a connecting flange, and a connector. One end of the gas pipeline is connected to the vent at the rear end of the positioning fixture body, and the other end of the gas pipeline is connected to the connector through the connecting flange.

9. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 8, characterized in that, The gas pipeline is a long, thin straight pipe located inside the spindle of the CNC lathe.

10. The high-precision length positioning device for secondary clamping of CNC lathes as described in claim 8, characterized in that, The connector is connected to the gas distributor of the CNC lathe.

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