Built-in feeding mechanism of numerical control lathe

Abstract

The built-in feeding mechanism comprises an air cylinder arranged in a main shaft, and an inner cavity of the air cylinder is slidably connected with a piston in an air-tight sealing mode in the axis direction of the main shaft; a pneumatic rotating connector is installed at the end, away from the workpiece, of the air cylinder, two air pipes are connected to the pneumatic rotating connector in parallel, one air pipe is used for providing a positive pressure air source, and the other air pipe is used for providing a negative pressure air source. The piston is controlled to move in the air cylinder through positive and negative pressure, so that workpieces are pushed to be fed outwards from the inside of the main shaft through movement of the piston during positive pressure; and the piston block moves into the rear end cover when being reset, and the rear end cover can be detached from the main shaft, so that a next new workpiece can be conveniently filled into the air cylinder.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and more specifically to a built-in feeding mechanism for a CNC lathe. Background Technology

[0002] In order to achieve automatic feeding, lathes usually have a material ejection mechanism at the rear end of the spindle to facilitate the ejection of the material from the spindle for processing. For example, the "Automatic feeding device for shaft parts with safety mechanism" disclosed in patent number CN207431275U realizes automatic feeding of shaft parts. However, installing the ejector mechanism at the rear end of the spindle occupies a large space, requiring additional usable space at the rear of the machine tool. Therefore, some designers have proposed an internal ejector mechanism, such as the "An Internal Ejector Mechanism" disclosed in patent number CN211589385U. This mechanism reduces the overall space required for adding a cylinder to the rear of the machine tool by installing the cylinder inside the spindle, reduces the fixed space on the spindle box, and saves space for the addition of other structures. However, installing the cylinder inside the spindle still occupies a lot of space. As the core rotating component of the lathe, the spindle's internal space is significantly compressed by the cylinder's built-in design. This not only places extremely high design requirements on the internal structural layout of the spindle, but the narrow internal space also compresses the distance between the cylinder and the original core components of the spindle, which can easily lead to structural interference risks. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a built-in feeding mechanism for CNC lathes to solve the aforementioned problems.

[0004] This invention provides the following technical solution: A built-in feeding mechanism for a CNC lathe includes a cylinder disposed in the spindle, and a piston is airtightly slidably connected to the inner cavity of the cylinder along the axis of the spindle. A pneumatic rotary joint is installed at the end of the cylinder away from the workpiece. Two air pipes are connected in parallel to the pneumatic rotary joint. One air pipe is used to provide a positive pressure air source, and the other air pipe is used to provide a negative pressure air source. When a positive pressure air source is input into the cylinder cavity, it pushes the piston to push the workpiece that is in contact with it outward from the spindle to achieve feeding. When the cylinder cavity is under negative pressure, it pushes the piston to move in the opposite direction to reset.

[0005] Preferably, one of the gas pipes providing a positive pressure gas source includes: a first solenoid valve and a pressure regulating valve installed on the gas pipe, and the gas pipe is connected to the positive pressure gas source.

[0006] Preferably, the air pipe for providing a negative pressure air source includes a second solenoid valve, a vacuum generator, and a third solenoid valve installed sequentially on the air pipe.

[0007] Preferably, it further includes a first rotary switch and a second rotary switch connected in parallel and interlocked; the first rotary switch is connected in series with the first solenoid coil of the first solenoid valve; the second rotary switch is connected in series with the second solenoid coil of the second solenoid valve; the second rotary switch is connected in series with the third solenoid coil of the third solenoid valve; and the second solenoid coil and the third solenoid coil are connected in parallel.

[0008] Preferably, it also includes a positioning block disposed on the outside of the spindle, the positioning block being used to limit the distance the workpiece is pushed outward from inside the spindle.

[0009] Preferably, the end of the spindle away from the chuck extends to the outside of the spindle and is detachably fitted with a rear end cover.

[0010] Preferably, the inner cavity of the rear end cover is consistent with and communicates with the inner cavity of the cylinder, the inner cavity of the rear end cover is sufficient to accommodate the piston, and the pneumatic rotary joint is disposed on the rear end cover.

[0011] Preferably, a sealing ring is provided between the main shaft and the rear end cover.

[0012] Preferably, the cylinder is coaxially fixed inside the main shaft via a cylinder fixing flange.

[0013] The present invention has the following beneficial technical effects: This invention controls the movement of the piston within the cylinder by controlling positive and negative pressure. Under positive pressure, the piston moves to push the workpiece from inside the spindle to the outside. Under negative pressure, the piston is attracted to move in the opposite direction to reset, facilitating reuse. When the piston block resets, it moves to the rear end cover, which can be removed from the spindle for easy loading of the next new workpiece into the cylinder.

[0014] There is no relative rotation between the piston block and the workpiece, which avoids wear caused by contact between the workpiece and the piston when the spindle rotates, and makes it easier to load new workpieces from outside the machine tool. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the present invention; Figure 2 This is the control circuit diagram of the present invention.

[0016] The attached figures are labeled as follows: 1. Positioning stop; 2. Workpiece; 3. Chuck; 4. Lathe spindle; 5. Cylinder; 6. Piston; 7. Cylinder mounting flange; 8. Socket head bolt; 9. Rear end cap; 10. Pneumatic rotary joint; 11. First solenoid valve; 12. Pressure regulating valve; 13. Air pipe; 14. Second solenoid valve; 15. Vacuum generator; 16. Third solenoid valve; 17. Sealing ring; 18. Lathe tool; 101. Air switch; 102. Switching power supply; 103. First rotary switch; 104. Second rotary switch; 105. Second solenoid valve coil; 106. Third solenoid valve coil; 107. First solenoid valve coil. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example: A CNC lathe with a built-in feeding mechanism, such as Figure 1 As shown: The spindle 4 can rotate, such as a lathe spindle, and a chuck 3 is installed at one end of the spindle 4; the first solenoid valve 11, the second solenoid valve 14 and the third solenoid valve 16 can all be pneumatic solenoid valves; the chuck 3 can be a three-jaw chuck, a four-jaw chuck or an electric chuck to clamp and fix the workpiece 2 in the spindle; the air pipe 13 is a flexible hose structure that can be deformed.

[0019] The spindle 4 drives the workpiece 2 to rotate via the chuck 3, and the workpiece 2 cooperates with the turning tool 18 on one side to achieve turning. This is existing technology and will not be described in detail here.

[0020] A positioning block 1 is provided in the direction of the spindle 4 axis. The positioning block 1 can be temporarily moved away during machining. Positioning is performed when it is moved to the direction of the spindle 4 axis. This is existing technology and will not be described in detail.

[0021] A cylinder 5 is coaxially fixed inside the spindle 4. A cylinder fixing flange 7 is coaxially fixed to the outer wall of the cylinder 5. The cylinder fixing flange 7 is installed on the end of the spindle 4 away from the chuck 3 by fasteners such as hexagonal bolts 8.

[0022] The cylinder 5 is hollow with openings at both ends. The end of the cylinder 5 away from the chuck 3 extends to the spindle 4 and the outside of the lathe. A coaxial rear end cover 9 is detachably installed at the end of the cylinder 5. The rear end cover 9 can be quickly installed and removed from the end of the cylinder 5 by means of a threaded connection, thereby closing the opening at the end of the cylinder 5. This allows the inner cavity of the rear end cover 9 and the inner cavity of the cylinder 5 to form an independent and closed space under the action of the piston 6. A sealing ring 17 is provided between the rear end cover 9 and the cylinder 5 to improve the sealing between them. The inner cavity of the rear end cover 9 and the inner cavity of the cylinder 5 are connected and their inner contours are consistent along their axis, together forming an inner cavity that allows the piston 6 to slide in an airtight manner. That is, the piston 6 can move arbitrarily between the inner cavity of the rear end cover 9 and the inner cavity of the cylinder 5, and the piston 6 can also be fully accommodated in the inner cavity of the rear end cover 9.

[0023] The distance between the other end of cylinder 5 away from the rear end cover 9 and the inner end face of the main shaft 4 is small, to prevent piston 6 from completely disengaging from the end of cylinder 5.

[0024] A pneumatic rotary joint 10 is coaxially mounted on the end of the rear end cover 9 away from the cylinder 5. Two parallel air pipes 13 are connected to the pneumatic rotary joint 10. The two air pipes 13 remain stationary when the rear end cover 9 rotates with the main shaft 4 via the pneumatic rotary joint 10.

[0025] One of the air pipes 13 is equipped with a first solenoid valve 11 and a pressure regulating valve 12. One end of the air pipe 13 is connected to a pneumatic rotary joint 10, and the other end is connected to an external positive pressure air source. Another air pipe 13 is equipped with a second solenoid valve 14, a vacuum generator 15 and a third solenoid valve 16 in sequence. One end of the air pipe 13 is connected to the pneumatic rotary joint 10, and the other end is connected to an external positive pressure air source or the atmosphere.

[0026] like Figure 2 The diagram shown is a circuit diagram for controlling the feeding mechanism. The circuit includes an air switch 101 and a switching power supply 102. The first solenoid valve coil 107 is part of the first solenoid valve 11, the second solenoid valve coil 105 is part of the second solenoid valve 14, and the third solenoid valve coil 106 is part of the third solenoid valve 16. The coils control the on / off state of the corresponding solenoid valves.

[0027] The circuit diagram has a first rotary switch 103 and a second rotary switch 104 connected in parallel. The first rotary switch 103 and the second rotary switch 104 are interlocked, so that one of the first rotary switches 103 and the second rotary switch 104 remains open and the other remains closed.

[0028] A first solenoid valve coil 107 is connected in series on the branch of the first rotary switch 103; a second solenoid valve coil 105 and a third solenoid valve coil 106 are connected in series on the branch of the second rotary switch 104, and the second solenoid valve coil 105 and the third solenoid valve coil 106 on this branch are connected in parallel.

[0029] Working principle: The workpiece 2, which has a shaft-like structure, is installed inside the cylinder 5, and one end of the workpiece 2 extends to the outside of the spindle 4 and the lathe and is clamped and fixed by the chuck 3.

[0030] When feeding is required, the chuck 3 is first controlled to release the clamped workpiece 2, the first rotary switch 103 is closed and the second rotary switch 104 is opened; the closure of the first rotary switch 103 energizes the first solenoid valve coil 107, thereby controlling the first solenoid valve 11 to open and connect, and the opening of the second rotary switch 104 de-energizes the second solenoid valve coil 105 and the third solenoid valve coil 106, thereby controlling the corresponding second solenoid valve 14 and the third solenoid valve 16 to close and block; at this time, the positive pressure air source enters the pneumatic rotary joint 10 through the pressure regulating valve 12 and the first solenoid valve 11 on one of the air pipes 13, and provides positive pressure air to the rear end cover 9 and the inner cavity of the cylinder 5 through the pneumatic rotary joint 10. The positive pressure air input into the rear end cover 9 and the inner cavity of the cylinder 5 pushes the piston 6 closer to one side of the chuck 3, thereby pushing the workpiece 2 that is in contact with the piston 6 outward. During the process of pushing the workpiece 2 outward, one end of it is limited and blocked by the positioning block 1, and then the chuck 3 is controlled to continue to clamp the workpiece 2.

[0031] During the machining process when the workpiece 2 is clamped by the chuck 3, the corresponding air pipe 13 can be blocked by the pressure regulating valve 12.

[0032] When a new workpiece 2 needs to be replaced, the first rotary switch 103 is opened and the second rotary switch 104 is closed. The opening of the first rotary switch 103 de-energizes the first solenoid valve coil 107, thereby controlling the first solenoid valve 11 to close. The closing of the second rotary switch 104 energizes the second solenoid valve coil 105 and the third solenoid valve coil 106, thereby controlling the corresponding second solenoid valve 14 and third solenoid valve 16 to open and connect. At this time, the external positive pressure gas source is not provided, and the vacuum generator 15 is controlled to work to extract the gas in the rear end cover 9 and the cylinder 5 cavity, so that the rear end cover 9 and the cylinder 5 cavity are in a negative pressure state. Under the negative pressure state, the piston 6 is controlled to move to the rear end cover 9 side, and finally the piston 6 moves into the rear end cover 9. Afterwards, the rear end cover 9 can be manually rotated outside the machine tool to remove it from the end of the cylinder 5, so that a new workpiece 2 can be inserted into the cylinder 5 from outside the machine tool. One end of the workpiece 2 is inserted into the chuck 3 for clamping. Then the rear end cover 9 can be installed on the end of the cylinder 5. At this time, the piston 6 is located on the side of the workpiece 2 closer to the rear end cover 9, and the above feeding action can be repeated.

[0033] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A built-in feeding mechanism for a CNC lathe, characterized in that, Includes a cylinder (5) installed in the main shaft (4), and a piston (6) is airtightly slidably connected to the inner cavity of the cylinder (5) along the axis of the main shaft (4); The cylinder (5) is equipped with a pneumatic rotary joint (10) at the end away from the workpiece. Two air pipes (13) are connected in parallel on the pneumatic rotary joint (10). One of the air pipes (13) is used to provide a positive pressure air source, and the other air pipe (13) is used to provide a negative pressure air source. When a positive pressure air source is input into the inner cavity of the cylinder (5), the piston (6) is pushed to push the workpiece (2) that is in contact with it outward from the spindle (4) to realize feeding. When the inner cavity of the cylinder (5) is under negative pressure, the piston (6) is pushed to move in the opposite direction to reset.

2. The built-in feeding mechanism of a CNC lathe according to claim 1, characterized in that, A gas pipe (13) providing a positive pressure gas source includes a first solenoid valve (11) and a pressure regulating valve (12) installed on the gas pipe (13), and the gas pipe (13) is connected to the positive pressure gas source.

3. The built-in feeding mechanism of a CNC lathe according to claim 2, characterized in that, The air pipe (13) for providing a negative pressure air source includes a second solenoid valve (14), a vacuum generator (15) and a third solenoid valve (16) installed sequentially on the air pipe (13).

4. The built-in feeding mechanism of a CNC lathe according to claim 3, characterized in that, It also includes a first rotary switch (103) and a second rotary switch (104) connected in parallel and interlocked; the first rotary switch (103) is connected in series with the first solenoid coil (107) of the first solenoid valve (11); the second rotary switch (104) is connected in series with the second solenoid coil (105) of the second solenoid valve (14), the second rotary switch (104) is connected in series with the third solenoid coil (106) of the third solenoid valve (16), and the second solenoid coil (105) and the third solenoid coil (106) are connected in parallel.

5. The built-in feeding mechanism of a CNC lathe according to claim 1, characterized in that, It also includes a positioning block (1) disposed on the outside of the spindle (4), the positioning block (1) being used to limit the distance the workpiece (2) is pushed outward from the inside of the spindle (4).

6. The built-in feeding mechanism of a CNC lathe according to claim 1, characterized in that, The end of the spindle (4) away from the chuck (3) extends to the outside of the spindle (4) and is detachably fitted with a rear end cover (9).

7. The built-in feeding mechanism of a CNC lathe according to claim 6, characterized in that, The inner cavity of the rear end cover (9) is consistent with and connected to the inner cavity of the cylinder (5). The inner cavity of the rear end cover (9) is sufficient to accommodate the piston (6). The pneumatic rotary joint (10) is provided on the rear end cover (9).

8. The built-in feeding mechanism of a CNC lathe according to claim 6, characterized in that, A sealing ring (17) is provided between the main shaft (4) and the rear end cover (9).

9. The built-in feeding mechanism of a CNC lathe according to claim 1, characterized in that, The cylinder (5) is coaxially fixed inside the main shaft (4) via the cylinder fixing flange (7).

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