A compact parallel drive double-chuck lathe spindle system

Abstract

The application discloses a compact parallel driving type double-chuck lathe spindle system, which comprises a driving spindle servo motor, a spindle box, a clamping chuck A, a clamping chuck B, a main shaft and a sub-spindle, wherein the main shaft and the sub-spindle are hollow shaft structures, and the main shaft is provided with oil inlet and outlet holes T1, T2 and T3 corresponding to the three sealed cavities Q1, Q2 and Q3 formed by a right hydraulic cylinder pull rod (16), a left hydraulic cylinder pull rod (17) and a left screw sleeve (19), and the main shaft system is matched with a hydraulic control system, the action of the clamping chuck A (3) and the clamping chuck B (12) is realized by controlling the volume of the hydraulic oil in the three sealed cavities, and the workpiece surface is prevented from being damaged by clamping by rising the hydraulic oil pressure in stages. The application has the advantages of simple structure, convenient and reliable control, stable and reliable positioning and clamping of long shaft parts, prevention of clamping deformation of the workpiece and improvement of machining quality.

Description

Technical Field

[0001] This invention relates to the field of machining, and in particular to a compact parallel drive double chuck lathe spindle system. Background Technology

[0002] A chuck is a device used on a lathe to position and clamp workpieces, ensuring that the workpiece is in the correct position during machining. The chuck has a direct and significant impact on machining efficiency, cost, quality, and safety, so its structural design should take into account practicality, economy, and reliability.

[0003] Traditional lathe spindle systems utilize a chuck to clamp one end of a shaft-like part, performing turning or drilling on the other end. To improve machining efficiency and speed, double-headed lathes have emerged in recent years; their characteristic is that they use a chuck to clamp the middle of the shaft-like part, simultaneously turning or drilling both sides of the workpiece. For long shaft-like parts, clamping the middle with a single chuck can result in significant positioning and machining errors, thus requiring two chucks to increase the clamping span. In existing solutions, electrical signals from the CNC system simultaneously control the clamping and releasing actions of the two chucks; however, due to subtle differences in the mechanical structure and control circuits of the two chucks, the consistency of their actions is difficult to reliably guarantee. When the clamping / releasing actions of the two chucks are significantly inconsistent, the workpiece will deviate laterally, leading to significant positioning errors; even with limited positioning errors, slight lateral deviation of the workpiece can cause high-pair contact between the workpiece and the chuck, resulting in mechanical damage to the workpiece surface and affecting the machining quality. On the other hand, although they share a single control signal, the movements of the two chucks are achieved by two sets of motion actuators, making the internal structure of the spindle system more complex and the manufacturing cost relatively high.

[0004] This invention provides a compact parallel-drive double chuck lathe spindle system, which uses the same hydraulic / pneumatic device to drive the clamping and releasing actions of the double chuck lathe spindle in parallel, enabling rapid and stable positioning and clamping of workpieces, improving the stability of turning operations, and effectively reducing damage to the workpiece surface caused by clamping actions. Summary of the Invention

[0005] This invention proposes a compact parallel-drive double-chuck lathe spindle system, which uses the same hydraulic / pneumatic device to drive the clamping and releasing actions of the double-chuck lathe spindle in parallel, enabling rapid positioning and clamping of workpieces, improving the stability of turning operations, and effectively reducing damage to the workpiece surface caused by clamping actions.

[0006] The present invention discloses a compact parallel-drive dual-chuck lathe spindle system, specifically comprising: a spindle servo motor, a spindle housing, clamping chucks A and B, a main spindle, and a sub-spindle; the spindle servo motor is mounted on the spindle housing, and a spur gear is connected to the end of the spindle servo motor, the spur gear meshing with a spur bevel gear mounted on the main spindle, the latter being fixed to the main spindle by a locking nut; the above-mentioned transmission mechanism transmits the rotational motion of the spindle servo motor to the main spindle and the sub-spindle;

[0007] The main spindle is connected to the sub-spindle, and both penetrate the spindle housing. From the main spindle side to the sub-spindle side, the following components are installed in sequence: clamping chuck A, spindle receiving plate A, right spindle flange, tapered roller bearing A, spur bevel gear, locking nut, oil distribution sleeve, tapered roller bearing B, left spindle flange, spindle receiving plate B, and clamping chuck B. These components respectively serve to fix the main spindle, sub-spindle, and gear.

[0008] The main shaft and the auxiliary main shaft are hollow shaft structures with different internal cross-sectional areas. The main shaft, the right hydraulic cylinder rod, the left hydraulic cylinder rod, and the left threaded sleeve respectively form sealing cavities Q1, Q2, and Q3. The main shaft is provided with oil inlet and outlet holes T1, T2, and T3 corresponding to sealing cavities Q1, Q2, and Q3. Hydraulic oil enters the sealing cavities through the oil inlet and outlet holes, thereby driving the left and right hydraulic cylinder rods in parallel. The left and right hydraulic cylinder rods are connected to clamping chucks A and B respectively, thereby realizing the clamping and releasing of the clamping chucks.

[0009] The specific method for achieving the clamping and releasing of the chuck is as follows: a wedge-shaped pad is provided at the end of the hydraulic cylinder rod, which converts the axial movement of the rod into the radial movement of the chuck jaws, thereby realizing the clamping and releasing action of the chuck.

[0010] The space inside the spindle housing, excluding the space where the various components are installed, stores lubricating oil, which lubricates the spur bevel gear and the spur helical gear.

[0011] Preferably, the volumes of the sealing cavities Q1, Q2, and Q3 change synchronously with the volume of hydraulic oil injected. Cavities Q1 and Q3 belong to the driving cavities for the release action of the clamping chuck A and the clamping chuck B, respectively, and Q2 is the driving cavity for the clamping action of the clamping chuck A and the clamping chuck B.

[0012] Preferably, the sealing cavity Q1 is provided with a bone-shaped sealing ring A at the contact end with the left threaded sleeve, the sealing cavity Q2 is provided with a bone-shaped sealing ring B at the contact end with the left hydraulic cylinder rod, and the sealing cavity Q3 is provided with a bone-shaped sealing ring C at the contact end with the main shaft;

[0013] Preferably, the inner side of the left threaded sleeve that mates with the main shaft is provided with an O-ring A, the inner side of the left hydraulic cylinder rod that mates with the main shaft is provided with an O-ring B, and the inner side of the right hydraulic cylinder rod that mates with the main shaft is provided with an O-ring C.

[0014] Preferably, the right hydraulic cylinder rod is threadedly connected to the transmission mechanism inside the clamping chuck A, and the left hydraulic cylinder rod is threadedly connected to the transmission mechanism inside the clamping chuck B. The axial movement of the right and left hydraulic cylinder rods driven by the power is converted into the radial movement of the jaws of the clamping chuck A and clamping chuck B, thereby realizing the clamping and releasing of the workpiece.

[0015] The outer end face of the right hydraulic cylinder tie rod is provided with a dustproof ring to prevent slag and metal particles on the workpiece surface from entering the gap between the right hydraulic cylinder tie rod and the left hydraulic cylinder tie rod.

[0016] Preferably, the dustproof ring is made of rubber or nylon, and its inner diameter is 1-10 mm smaller than the minimum outer diameter of the long shaft workpiece.

[0017] Pressure sensors are installed inside the sealing cavities Q1, Q2 and Q3 to monitor the liquid pressure inside the sealing cavities in real time.

[0018] To prevent the clamping chuck from damaging the workpiece surface, preferably, during the clamping action of the clamping chuck, the liquid pressure in the sealing cavity Q2 increases in stages; before the clamping chuck fully clamps the workpiece, the liquid pressure in the sealing cavity Q2 is 70-85% of the final clamping pressure; when the clamping chuck has fully clamped the workpiece, the liquid pressure in the sealing cavity Q2 rises to the final clamping pressure.

[0019] Preferably, a retractable caliper, horizontal to the spindle centerline, is installed on the side of the spindle housing parallel to the spindle. When positioning the workpiece, the distance from the end face of the workpiece to the outer end face of the clamping chuck is measured online using the caliper, thereby enabling rapid verification of the workpiece positioning accuracy.

[0020] Preferably, the spindle box is provided with oil drain holes at both the front and rear ends. The oil drain hole at the front end is 2-5mm from the bottom of the spindle box, and the oil drain hole at the rear end is 70-90mm from the bottom of the spindle box. The volume of hydraulic oil stored in the spindle box can be adjusted through the above two oil drain holes. Attached Figure Description

[0021] Figure 1 Top view of the spindle system

[0022] Figure 2 Sectional view of the spindle system (AA section)

[0023] Figure 3 Enlarged view of section AA of the spindle system

[0024] Figure 4Schematic diagram of workpiece clamping in spindle system

[0025] Figure 5 Axonometric view of the AA section section of the spindle system

[0026] In the diagram, 1 is the spindle servo motor; 2 is the spindle housing; 3 is the clamping chuck A; 4 is the spindle receiving plate A; 5 is the spindle; 6 is the right spindle flange; 7 is the spur bevel gear; 8 is the locking nut; 9 is the oil distribution sleeve; 10 is the left spindle flange; 11 is the sub-spindle; 12 is the clamping chuck B; 13 is the spindle receiving plate B; 14 is the spur helical gear; 15 is the tapered roller bearing B; 16 is the right hydraulic cylinder connecting rod; 17 is the left hydraulic cylinder connecting rod; 18 is the tapered roller bearing A; 19 is the left threaded sleeve; 20 is the flat key A; 21 is the flat key B; 22 is the bone-type seal A; 23 is the bone-type seal B; 24 is the bone-type seal C; 25 is the O-ring A; 26 is the O-ring B; 27 is the O-ring C; 28 is the dustproof retainer ring; and 29 is the workpiece. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are provided to help better understand the technical principles of the present invention; the scope of protection of the present invention is not limited to the following examples; similar technical solutions to the present invention also fall within the scope of protection of the present invention.

[0028] Example 1.

[0029] like Figure 1 , 2 As shown in Figure 4, the spindle system includes: a spindle servo motor 1, a spindle housing 2, a clamping chuck A3 and a clamping chuck B12, a main spindle 5 and a sub-spindle 11; the clamping chuck A3 and the clamping chuck B12 are three-jaw chucks or cylindrical clamps;

[0030] The spindle servo motor 1 is mounted on the spindle housing 2, and a spur gear 14 is connected to its end; the spur gear 14 meshes with a bevel gear 7 mounted on the spindle 5, and the bevel gear 7 is fixed on the spindle by a locking nut 8;

[0031] The main spindle 5 and the auxiliary spindle 11 are fixedly connected by a flat key A20 and pass through the main spindle housing 2. From one side of the main spindle to the other side of the auxiliary spindle, the following components are installed in sequence: clamping chuck A3, main spindle receiving plate A4, main spindle right flange 6, tapered roller bearing A18, bevel gear 7, locking nut 8, oil distribution sleeve 9, tapered roller bearing B15, main spindle left flange 10, main spindle receiving plate B13 and clamping chuck B12. While fixing the main spindle and the auxiliary spindle, the gear drives their movement. The main spindle receiving plate A4 is connected to the main spindle 5 by screws, and the other side is fixedly embedded in the side end of the clamping chuck A3. The locking nut 8 and the flat key B21 fix the bevel gear 7.

[0032] The main shaft 5 and the auxiliary main shaft 11 are hollow shaft structures, forming three sealing cavities Q1, Q2, and Q3 together with the right hydraulic cylinder pull rod 16, the left hydraulic cylinder pull rod 17, and the left threaded sleeve 19. Sealing cavities Q1 and Q3 respectively drive the releasing action of clamping chuck A3 and clamping chuck B12, while sealing cavity Q2 drives the clamping action of clamping chuck A3 and clamping chuck B12.

[0033] The spindle is equipped with oil inlet / outlet holes T1, T2, and T3, which communicate with sealing cavities Q1, Q2, and Q3, respectively. When hydraulic oil is injected into sealing cavities Q1 and Q3 through oil inlet / outlet holes T1 and T3, respectively, the hydraulic oil pressure drives the right hydraulic cylinder rod 16 to move 5-50mm to the left, causing the clamping chuck A3 to loosen; simultaneously, it drives the left hydraulic cylinder rod 17 to move the same distance to the right, causing the clamping chuck B12 to loosen. When the hydraulic oil in sealing cavities Q1 and Q3 is discharged, and hydraulic oil is injected into sealing cavity Q2 through oil inlet / outlet hole T2, the right hydraulic cylinder rod 16 and the left hydraulic cylinder rod 17 move simultaneously to the right and left, respectively, causing the clamping chuck A3 and clamping chuck B12 to clamp.

[0034] According to embodiments of the present invention, such as Figure 3 As shown, the sealing cavity Q1 has a bone-shaped sealing ring A22 at the contact end with the left threaded sleeve 19, the sealing cavity Q2 has a bone-shaped sealing ring B23 at the contact end with the left hydraulic cylinder pull rod 17, and the sealing cavity Q3 has a bone-shaped sealing ring C24 at the contact end with the main shaft 5; the inner side of the left threaded sleeve 19 that mates with the main shaft 5 has an O-ring sealing ring A25, the inner side of the left hydraulic cylinder pull rod 17 that mates with the main shaft 5 has an O-ring sealing ring B26, and the inner side of the right hydraulic cylinder pull rod 16 that mates with the main shaft 5 has an O-ring sealing ring C27. These features ensure the sealing performance of each sealing cavity during movement and ultimately allow the clamping chuck to operate according to the set requirements.

[0035] Hydraulic oil enters the sealed cavity through the inlet and outlet ports, thereby driving the left and right hydraulic cylinder rods in parallel. The left and right hydraulic cylinder rods are connected to the clamping chuck A3 and clamping chuck B12 respectively, thus realizing the clamping and releasing of the clamping chuck.

[0036] The specific method for achieving the clamping and releasing of the chuck is as follows: a wedge-shaped pad is provided at the end of the hydraulic cylinder rod, which converts the axial movement of the rod into the radial movement of the chuck jaws, thereby realizing the clamping and releasing action of the chuck.

[0037] The outer end face of the right hydraulic cylinder pull rod is provided with a dustproof ring 28 to prevent slag and metal particles on the surface of the workpiece from entering the gap between the right hydraulic cylinder pull rod and the left hydraulic cylinder pull rod; preferably, the dustproof ring is made of rubber or nylon, and its inner diameter is 1-10mm smaller than the minimum outer diameter of the long shaft type workpiece.

[0038] The spindle housing 2 has a reserved space inside, which can store the hydraulic oil flowing out of the spindle 5. The hydraulic oil can lubricate the bevel gear 7 and the spur gear 14, and can also be recycled and reused.

[0039] To prevent the clamping chuck from damaging the workpiece surface, preferably, pressure sensors are installed inside the sealing cavities Q1, Q2, and Q3. During the clamping action of the clamping chuck, the liquid pressure in the sealing cavity Q2 is controlled by the liquid pressure sensors to rise in stages. Before the clamping chuck fully clamps the workpiece, the hydraulic oil pressure in the sealing cavity Q2 is 80% of the final clamping pressure, i.e., 0.8 MPa. When the clamping chuck has fully clamped the workpiece, the hydraulic oil pressure in the sealing cavity Q2 rises to the final clamping pressure, i.e., 1.0 MPa.

[0040] According to this embodiment, the lathe spindle system further includes: pressure sensors installed inside the sealing cavities Q1, Q2, and Q3. These pressure sensors measure the pressure in the sealing cavities in real time to determine the cause of any malfunction in the lathe spindle system. For example, if the liquid pressure in sealing cavities Q1 and Q3 is significantly higher than normal, but the chuck is not fully released, it indicates the presence of metal filings in the gap between the right hydraulic cylinder rod 16 and the left hydraulic cylinder rod 17. These metal filings obstruct the relative movement of the right hydraulic cylinder rod 16 and the left hydraulic cylinder rod 17, preventing the hydraulic oil in sealing cavity Q2 from being smoothly discharged under normal pressure conditions. In this case, the gap needs to be cleaned. Furthermore, if a pressure difference occurs between sealing cavities Q1 and Q3 during chuck clamping or releasing, it indicates significant obstruction in the mechanical structure of the chuck on the side with higher pressure, requiring cleaning or lubrication.

[0041] According to an embodiment of the present invention, the lathe spindle system further includes: a retractable caliper, horizontal to the spindle centerline, mounted on the side of the spindle housing parallel to the spindle, with a maximum range set to 500~800mm; the center distance between the two end faces of clamping chuck A3 and clamping chuck B12 is designed to be 1000mm, with the two end faces serving as reference surfaces; the caliper is used to achieve rapid positioning of the workpiece machining point; when positioning the workpiece, the caliper is used to measure the distance from the end face of the workpiece to the outer end face of the clamping chuck online, thereby achieving rapid verification of the workpiece positioning accuracy;

[0042] According to an embodiment of the present invention, the machine tool fixture may further include: an oil drain hole is provided on each of the front and rear end faces of the spindle box, the front oil drain hole is 2-5mm from the bottom, and the rear oil drain hole is 70-90mm from the bottom, and is plugged with a leak-proof bolt when not in use.

[0043] Example 2.

[0044] The workpiece in Example 2 is a long shaft type workpiece 29 with a length of 1200mm and a diameter of 100mm, such as... Figure 4 As shown.

[0045] First, hydraulic oil is injected into sealing chambers Q1 and Q3 through oil inlet / outlet holes T1 and T3. The hydraulic oil pressure drives the right hydraulic cylinder rod 16 to move to the left, and causes the clamping chuck A3 to release. At the same time, the hydraulic oil pressure drives the left hydraulic cylinder rod 17 to move to the right, and causes the clamping chuck B12 to release.

[0046] The second step involves manually or robotically placing workpiece 29 into the processing position.

[0047] Third step, open oil inlet / outlet T1 and oil inlet / outlet T3; fill hydraulic oil into sealing cavity Q2 through oil inlet / outlet T2; right hydraulic cylinder rod 16 and left hydraulic cylinder rod 17 move 7mm to the right and left respectively, driving clamping chuck A3 and clamping chuck B12 to perform clamping action.

[0048] In the fourth step, the spindle servo motor 1 drives the spur gear 14 to rotate, the spur gear 14 drives the bevel gear 7 to rotate, and the bevel gear 7 drives the main spindle 5 and the sub-spindle 11 to rotate, thus completing the turning operation.

[0049] Example 3.

[0050] The technical features that distinguish Example 3 from Examples 1 and 2 are as follows: the power source for driving the axial movement of the right hydraulic cylinder rod 16 and the left hydraulic cylinder rod 17 is an oil-gas mixture; gas pressure sensors are installed inside the sealing cavities Q1, Q2 and Q3.

[0051] Using a pneumatic control system, the gas pressure in the sealing cavity Q2 is controlled during the clamping action of the chuck. After the chuck fully clamps the workpiece with a constant gas pressure of 0.5 MPa, the gas pressure in the sealing cavity Q2 is further increased by 200% to 1.0 MPa to ensure the stability of workpiece clamping during machining.

[0052] This invention is not limited to the matters shown in the above embodiments. Modifications and adaptations made by those skilled in the art based on the description in the specification and well-known techniques are acceptable to this invention and are included within the scope of the claims.

Claims

1. A compact parallel drive dual chuck lathe spindle system, characterized by include: Main spindle servo motor (1), main spindle housing (2), clamping chuck A (3) and clamping chuck B (12), main spindle (5) and sub-spindle (11); The spindle servo motor (1) is mounted on the spindle housing (2) and has a spur gear (14) connected to its end. The spur gear (14) meshes with a bevel gear (7) mounted on the spindle (5). The bevel gear (7) is fixed to the spindle by a locking nut (8). The main spindle (5) and the secondary spindle (11) are fixedly connected together by a flat key A (20) and pass through the spindle housing (2); from the main spindle side to the secondary spindle side, the following are installed in sequence: clamping chuck A (3), spindle receiving plate A (4), right spindle flange (6), tapered roller bearing A (18), bevel gear (7), locking nut (8), oil distribution sleeve (9), tapered roller bearing B (15), left spindle flange (10), spindle receiving plate B (13) and clamping chuck B (12); The main shaft (5) and the auxiliary main shaft (11) are hollow shaft structures, forming sealing cavities Q1, Q2 and Q3 with the right hydraulic cylinder rod (16), the left hydraulic cylinder rod (17) and the left threaded sleeve (19); the main shaft (5) is provided with oil inlet and outlet holes T1, T2 and T3 corresponding to the sealing cavities. The sealing cavity Q1 is provided with a bone-shaped sealing ring A (22) at the contact end with the left threaded sleeve (19), the sealing cavity Q2 is provided with a bone-shaped sealing ring B (23) at the contact end with the left hydraulic cylinder pull rod (17), and the sealing cavity Q3 is provided with a bone-shaped sealing ring C (24) at the contact end with the main shaft (5). The inner side of the left threaded sleeve (19) that mates with the main shaft (5) is provided with an O-ring A (25), the inner side of the left hydraulic cylinder rod (17) that mates with the main shaft (5) is provided with an O-ring B (26), and the inner side of the right hydraulic cylinder rod (16) that mates with the main shaft (5) is provided with an O-ring C (27). Hydraulic oil enters the sealed cavity through the inlet and outlet oil holes, thereby driving the left hydraulic cylinder rod (17) and the right hydraulic cylinder rod (16) in parallel. The left hydraulic cylinder rod (17) and the right hydraulic cylinder rod (16) are respectively connected to the clamping chuck A (3) and the clamping chuck B (12), thereby realizing the clamping and releasing of the clamping chuck.

2. A compact parallel drive dual-chuck lathe spindle system according to claim 1, characterized in that: The power source for driving the right hydraulic cylinder rod (16) and the left hydraulic cylinder rod (17) to move axially is hydraulic or pneumatic; the movement distance of the right hydraulic cylinder rod (16) and the left hydraulic cylinder rod (17) is 5-50mm.

3. A compact parallel drive dual-chuck lathe spindle system according to claim 2, characterized in that: If the power source for driving the axial movement of the right hydraulic cylinder rod (16) and the left hydraulic cylinder rod (17) is hydraulic, then liquid pressure sensors are installed inside the sealing cavities Q1, Q2 and Q3. Using the liquid pressure sensors, the liquid pressure in the sealing cavity Q2 is controlled to rise in stages during the clamping action of the clamping chuck. Before the clamping chuck fully clamps the workpiece, the hydraulic oil pressure in the sealing cavity Q2 is 70-85% of the final clamping pressure. When the clamping chuck clamps the workpiece, the hydraulic oil pressure in the sealing cavity Q2 rises to the final clamping pressure.

4. A compact parallel drive dual-chuck lathe spindle system according to claim 2, characterized in that: If the power source for driving the axial movement of the right hydraulic cylinder rod (16) and the left hydraulic cylinder rod (17) is air pressure, then gas pressure sensors are installed inside the sealing cavities Q1, Q2 and Q3; the gas is an oil-gas mixture containing tiny lubricating oil droplets; using the air pressure control system, the gas pressure in the sealing cavity Q2 is controlled during the clamping action of the chuck; after the workpiece is clamped by the chuck, the gas pressure in the sealing cavity Q2 is further increased by 50-200%.

5. A compact parallel drive dual chuck lathe spindle system according to claim 1, wherein: A telescopic caliper, level with the spindle centerline, is installed on the side of the spindle housing parallel to the spindle. The maximum range is set to 500~800mm.

6. A compact parallel drive dual chuck lathe spindle system according to claim 1, characterized in that: The spindle box has an oil drain hole on each of its front and rear ends. The front drain hole is 2-5mm from the bottom, and the rear drain hole is 70-90mm from the bottom. When not in use, the drain holes should be plugged with anti-leakage bolts.

7. A compact parallel drive dual chuck lathe spindle system according to claim 1, wherein: The clamping chuck A (3) and clamping chuck B (12) are three-jaw chucks or cylindrical clamps; the outer end face of the right hydraulic cylinder pull rod (16) is provided with a dustproof ring (28); the space inside the spindle housing (2) is used to store lubricating oil, except for the space where the various components are installed.

8. A compact, parallel drive dual-chuck lathe spindle system according to claim 1, characterized in that: The specific method for achieving the clamping and releasing of the chuck is as follows: a wedge-shaped pad is provided at the end of the hydraulic cylinder rod, which converts the axial movement of the rod into the radial movement of the chuck jaws, thereby realizing the clamping and releasing action of the chuck.

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