A center-of-gravity driven CNC lathe with zero overhang

Abstract

The present invention discloses a center-of-gravity driven zero overhang CNC lathe, comprising a bed, a transverse guide rail, a longitudinal guide rail, a spindle unit, and a tool holder unit; the transverse guide rail is fixed to the top of the bed, the longitudinal guide rail is fixed to the side of the bed connected to the outside, the spindle unit is connected to the transverse guide rail for horizontal reciprocating motion, the tool holder unit is connected to the longitudinal guide rail for vertical reciprocating motion, and both the spindle unit and the tool holder unit are designed with zero overhang. Beneficial effects of the present invention: The present invention realizes the coordination of zero overhang and center-of-gravity drive, which can weaken the torque on the spindle unit during workpiece processing, reduce the relative vibration between the workpiece and the tool, improve processing accuracy and stability, and extend the service life of the tool.

Description

Technical Field

[0001] The invention relates to a numerically controlled machine tool, in particular to a center-of-gravity driven zero-overhang numerically controlled lathe. Background Art

[0002] With the rapid development of my country's manufacturing industry, production equipment technology is actively transforming towards precision, efficiency and intelligence. In the processing of rotating parts, CNC lathes have gradually replaced traditional lathes due to their high production efficiency, good safety (no human intervention is required in the processing process) and stable processing accuracy. In order to further pursue processing efficiency, some CNC lathes are equipped with robotic arms next to them to realize automatic loading and unloading, but this will bring additional costs and safety hazards. Therefore, the German Emag company invented a CNC lathe with an inverted spindle. Its spindle has two degrees of freedom of motion, lateral and longitudinal, and can realize automatic loading and unloading through the movement of the spindle and the gripping of the hydraulic chuck. All inverted lathes in the future adopted this structure until Mr. Li Luyang proposed an inverted CNC lathe with two axes in patent CN104874815B. The lathe removes the longitudinal degree of freedom of the spindle and changes it to the longitudinal movement of the tool holder. The parts are processed with the lateral feed of the spindle, and the two degrees of freedom of motion are separated, which improves the rigidity of the lathe to a certain extent, which is conducive to more precise and stable parts processing.

[0003] The current inverted CNC lathes, whether they have bidirectional spindle linkage or two-axis separate spindles, have a certain amount of overhang on the spindle or tool holder relative to the direction of the driving force. This will not produce significant negative effects when the spindle or tool holder moves unloaded. However, when the workpiece is fed, due to the existence of the spindle overhang, the reaction force on the tool feed and the horizontal driving force are not on the same vertical plane. Under the joint action of the two forces, the spindle unit (including the spindle and the horizontal saddle for mounting the spindle) will be subjected to a torque perpendicular to the horizontal plane, causing relative vibration between the workpiece and the tool, reducing the machining accuracy of the workpiece and the service life of the tool.

[0004] In view of the above-mentioned defects, the designer actively carried out research and innovation in order to create an inverted CNC lathe with no overhang and driven by the center of gravity, so as to make it more valuable for industrial use. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a CNC lathe which solves the problem in the above-mentioned background technology that the overhang of the spindle or tool holder causes relative vibration between the workpiece and the tool.

[0006] The present invention solves the above technical problems through the following technical solutions: The present invention comprises a bed, a transverse guide rail, a longitudinal guide rail, a spindle unit, and a tool holder unit;

[0007] The bed is a structure with a hollow interior and a top surface and one of the side surfaces connected to the outside, the transverse guide rail is fixed to the top of the bed, the longitudinal guide rail is fixed to the side of the bed connected to the outside, the spindle unit is connected to the transverse guide rail so as to be able to reciprocate horizontally, and the tool holder unit is connected to the longitudinal guide rail so as to be able to reciprocate vertically;

[0008] The transverse guide rail is a symmetrical structure, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit is located coincides with the symmetry plane of the transverse guide rail. The longitudinal guide rail is a symmetrical structure, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the tool holder unit is located coincides with the symmetry plane of the longitudinal guide rail.

[0009] Preferably, the bed is a hexahedral structure that is symmetrical along the vertical direction, with a rectangular cavity structure inside, and the top surface and four side surfaces are connected to the outside.

[0010] Preferably, the transverse guide rails are two mutually parallel horizontal guide rails, symmetrically fixedly mounted on the top of the bed, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit is located coincides with the symmetry planes of the two horizontal guide rails.

[0011] Preferably, the spindle unit comprises a spindle box, a spindle, and a spindle chuck. The spindle box is slidably connected to the transverse guide rail, the spindle passes through the spindle box and is fixed on the spindle box, and the spindle chuck is installed at the lower end of the spindle.

[0012] Preferably, it also includes a spindle drive device for driving the spindle unit to move horizontally and reciprocatingly, which is installed on the top of the bed. When the spindle drive device drives the spindle unit to move, the direction of the line of action of the driving force generated by the spindle drive device coincides with the movement trajectory of the center of gravity of the spindle unit.

[0013] Preferably, the longitudinal guide rails are two mutually parallel vertical guide rails, symmetrically fixedly mounted on the sides of the bed, and the vertical plane where the trajectory generated by the vertical movement of the center of gravity of the tool holder unit lies coincides with the symmetry planes of the two vertical guide rails.

[0014] Preferably, the tool holder unit comprises a tool holder box, a tool holder, and a tool. The tool holder box can be slidably connected to the longitudinal guide rail, the tool holder is fixed on the tool holder box, and the tool is fixed on the tool holder.

[0015] Preferably, it also includes a tool holder driving device for driving the tool holder unit to vertically reciprocate, which is installed on the side of the bed. When the tool holder driving device drives the tool holder unit to move, the direction of the line of action of the driving force generated by the tool holder driving device coincides with the movement trajectory of the center of gravity of the tool holder unit.

[0016] Preferably, it also includes a counterweight unit for balancing the weight of the tool holder unit, which is arranged on one side of the tool holder unit. The counterweight unit includes a counterweight block, a counterweight rope, a counterweight wheel, a counterweight block guide rail, and a counterweight slider. The counterweight block guide rail is fixed to the side of the bed, and the counterweight wheel is rotatably installed on the top of the counterweight block guide rail. The counterweight rope crosses the counterweight wheel, one end of which is connected to the tool holder box, and the other end is connected to the counterweight block, and one side of the counterweight block is fixedly connected to the counterweight slider, and the counterweight slider is connected to the counterweight block guide rail so as to be able to reciprocate in the vertical direction.

[0017] Preferably, it further comprises a base, and the bed is detachably mounted on the base.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) By placing the spindle unit and the tool holder unit across the bed, the horizontal plane where the trajectory of the center of gravity of the spindle unit is located coincides with the symmetry plane of the transverse guide rail, and the vertical plane where the trajectory of the center of gravity of the tool holder unit is located coincides with the symmetry plane of the longitudinal guide rail, thereby achieving zero overhang of the spindle and the tool holder, and improving the rigidity of the system;

[0020] (2) The direction of the line of action of the driving force generated by the spindle drive device coincides with the trajectory of the center of gravity of the spindle unit, and the direction of the line of action of the driving force generated by the tool holder drive device coincides with the trajectory of the center of gravity of the tool holder unit, thereby realizing center of gravity drive, eliminating the torque caused by the non-coplanarity of the feed force and the driving force, and combining with the zero overhang, effectively reducing the relative vibration between the workpiece and the tool, thereby improving the machining accuracy and stability;

[0021] (3) The bed with symmetrical structure has higher strength and rigidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a zero overhang and center-of-gravity driven CNC lathe according to an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle bed;

[0024] Figure 3 yes Figure 1 Schematic diagram of the structure of the middle transverse guide rail and the spindle unit

[0025] Figure 4 yes Figure 1 Schematic diagram of the structure of the middle longitudinal guide rail, tool holder unit and counterweight unit.

[0026] Numbers in the figure: including bed 1, window 11, transverse guide rail 2, horizontal guide rail 21, longitudinal guide rail 3, vertical guide rail 31, spindle unit 4, spindle box 41, spindle 42, spindle chuck 43, spindle drive device 44, tool holder unit 5, tool holder box 51, tool holder 52, tool 53, tool holder drive device 54, counterweight unit 6, counterweight block 61, counterweight rope 62, counterweight wheel 63, counterweight block guide rail 64, counterweight slide block 65, base 7, workpiece 8. DETAILED DESCRIPTION

[0027] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0028] like Figure 1 As shown, the present embodiment is a center-of-gravity driven zero-overhang CNC lathe, comprising a bed 1, a transverse guide rail 2, a longitudinal guide rail 3, a spindle unit 4, a tool holder unit 5, a counterweight unit 6, and a base 7.

[0029] The bed 1 is a structure with a hollow interior and a top surface and one of the side surfaces connected to the outside. The transverse guide rail 2 is fixed to the top of the bed 1, that is, the top surface connected to the outside. The longitudinal guide rail 3 is fixed to the left side of the bed 1 connected to the outside. It is set here that the side on which the tool holder unit 5 is installed is the left side, and the side opposite to it is the right side. The spindle unit 4 is connected to the transverse guide rail 2 so as to be able to reciprocate horizontally, and the tool holder unit 5 is connected to the longitudinal guide rail 3 so as to be able to reciprocate vertically. When working, the horizontal plane where the trajectory generated by the movement of the center of gravity of the spindle unit 4 is located coincides with the support surface of the transverse guide rail 2.

[0030] The transverse guide rail 2 is a symmetrical structure, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit 4 lies coincides with the symmetry plane of the transverse guide rail 2. The longitudinal guide rail 3 is a symmetrical structure, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the tool holder unit 5 lies coincides with the symmetry plane of the longitudinal guide rail 3.

[0031] like Figure 2 As shown, the bed 1 is a hexahedral structure symmetrical along the vertical direction, with a rectangular cavity structure inside. The top, front, back, left and right sides are all connected to the outside. The front and back of the bed 1 shown in the figure are provided with four windows 11, which are symmetrically arranged. The window 11 is used for testing and aligning the spindle unit 4 and the tool holder unit 5 and for installing and maintaining the loading and unloading platforms. The top surface is provided with two rows of mounting holes for installing the transverse guide rail 2, and the left side is provided with two rows of mounting holes for installing the tool holder unit 5.

[0032] like Figure 3As shown, the transverse guide rails 2 are two parallel horizontal guide rails 21 symmetrically fixed on the top of the bed, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit 4 is located coincides with the symmetry plane of the two horizontal guide rails 21 .

[0033] The spindle unit 4 includes a spindle box 41, a spindle 42, and a spindle chuck 43. The spindle box 41 can be slidably connected to the transverse guide rail 2. The spindle box 41 is a symmetrical structure, and a transmission system for driving the spindle to rotate is provided inside. Specifically, the spindle box 41 can be fixedly connected to four spindle box slides by bolts on both sides of the spindle box 41. The four spindle box slides are slidably clamped on the two horizontal guide rails 21 of the transverse guide rail. The spindle 42 passes through the spindle box 41 and is fixed on the spindle box 41. The spindle chuck 43 is installed at the lower end of the spindle 42 for clamping the workpiece 8.

[0034] This embodiment also includes a spindle drive device 44 for driving the spindle unit 4 to reciprocate horizontally, which is installed on the top of the bed 1. When the spindle drive device 44 drives the spindle unit 4 to move, the direction of the line of action of the driving force generated by the spindle drive device 44 coincides with the trajectory of the center of gravity of the spindle unit 4. In this embodiment, the spindle drive device 44 is a gear transmission system and a horizontal linear motor arranged on both sides of the spindle unit 4 along the movement direction of the spindle unit 4. Other transmission systems suitable for generating driving force by this device, such as reciprocating telescopic realization using a cylinder, a hydraulic cylinder, etc., are all within the protection scope of the present invention.

[0035] like Figure 4 As shown, the longitudinal guide rails 3 are two vertical guide rails 31 parallel to each other, which are symmetrically fixed on the side of the bed 1. The vertical plane where the trajectory generated by the vertical movement of the center of gravity of the tool holder unit 5 is located coincides with the symmetry planes of the two vertical guide rails 31. In the present invention, the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit 4 is located coincides with the vertical plane where the trajectory generated by the vertical movement of the center of gravity of the tool holder unit 5 is located.

[0036] The tool holder unit 5 includes a tool holder box 51, a tool holder 52, and a tool 53. The tool holder box 51 can be slidably connected to the longitudinal guide rail 3, the tool holder 52 is fixed on the tool holder box 51, and the tool 53 is fixed on the tool holder 52. The tool holder 52 is a rotating structure, and multiple tools 53 can be installed on it. This embodiment also includes a tool holder driving device 54 for driving the tool holder unit 5 to reciprocate vertically, which is installed on the side of the bed 1. When the tool holder driving device 54 drives the tool holder unit 5 to move, the direction of the line of action of the driving force generated by the tool holder driving device 54 coincides with the movement trajectory of the center of gravity of the tool holder unit 5. In this embodiment, the tool holder driving device 54 is a gear transmission system and a vertical linear motor arranged on both sides of the tool holder unit 4 along the movement direction of the tool holder unit 4. Other transmission systems suitable for generating driving force for this device, such as reciprocating telescopic realization using cylinders, hydraulic cylinders, etc., are all within the protection scope of the present invention.

[0037] This embodiment also includes a counterweight unit 6 for balancing the weight of the tool holder unit 5, which is arranged on one side of the tool holder unit 6. The counterweight unit 6 includes a counterweight block 61, a counterweight rope 62, a counterweight wheel 63, a counterweight block guide rail 64, and a counterweight slider 65. The counterweight block guide rail 64 is fixed to the side of the bed 1, and the counterweight wheel 63 is rotatably installed on the top of the counterweight block guide rail 64. The counterweight rope 62 crosses the counterweight wheel 63, one end of which is connected to the tool holder box 51, and the other end is connected to the counterweight block 61, and one side of the counterweight block 61 is fixedly connected to the counterweight slider 65, and the counterweight slider 65 is connected to the counterweight block guide rail 64 so as to be able to reciprocate in the vertical direction.

[0038] This embodiment further includes a base 7 , and the bed 1 is detachably mounted on the base 7 . The base 7 is a rectangular body slightly larger than the bottom of the base 1 .

[0039] Working process of the present invention:

[0040] The workpiece 8 is clamped onto the spindle chuck 43 manually or by an automatic loading and unloading robot. After the spindle chuck 43 clamps the workpiece 8, the linear motor in the spindle drive device 44 drives the spindle unit 4 to move rapidly to the left along the gear bar to a preset processing position, that is, the upper position of the tool holder unit 5. In this process, the spindle 42 is accelerated to a preset speed, and then the spindle drive device 44 drives the spindle unit 4 to feed horizontally, while the tool holder drive device 54 drives the tool holder unit 5 to feed vertically. The two drive the workpiece 8 according to the preset processing procedures. After the workpiece 8 is processed, during the process of the tool holder driving device 54 driving the tool holder unit 5, the counterweight block 61 balances the weight of the tool holder unit 5, so that the vertical feed is not affected by the gravity of the tool holder unit 5. After the workpiece 8 is processed, the tool holder unit 5 returns to its initial position under the drive of the tool holder driving device 54, and the spindle unit 4 returns the processed workpiece 8 to its initial position under the drive of the spindle driving device 44, and disassembles it with a manual or automatic loading and unloading device, and replaces it with a new workpiece 8 to be processed. At this point, one processing cycle is completed.

[0041] In summary, the present invention achieves zero overhang of the spindle unit 4 and the tool holder unit 5 by placing the spindle unit 4 and the tool holder unit 5 across the bed 1, thereby improving the system rigidity. On the other hand, since the spindle driving force and the tool holder driving force respectively pass through the center of gravity of the spindle unit 4 and the center of gravity of the tool holder unit 5, the torque caused by the non-coplanarity of the feed force and the driving force is eliminated, the relative vibration between the workpiece 8 and the tool 53 is reduced, and the processing accuracy and stability are improved.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A center-of-gravity driven zero overhang CNC lathe, characterized in that: It includes bed, transverse guide rail, longitudinal guide rail, spindle unit and tool holder unit; The bed is a structure with a hollow interior and a top surface and one of the side surfaces connected to the outside, the transverse guide rail is fixed to the top of the bed, the longitudinal guide rail is fixed to the side of the bed connected to the outside, the spindle unit is connected to the transverse guide rail so as to be able to reciprocate horizontally, and the tool holder unit is connected to the longitudinal guide rail so as to be able to reciprocate vertically; It also includes a counterweight unit for balancing the weight of the tool holder unit, which is arranged on one side of the tool holder unit. The counterweight unit includes a counterweight block, a counterweight rope, a counterweight wheel, a counterweight block guide rail, and a counterweight slider. The counterweight block guide rail is fixed to the side of the bed, and the counterweight wheel is rotatably installed on the top of the counterweight block guide rail. The counterweight rope crosses the counterweight wheel, one end of which is connected to the tool holder box, and the other end is connected to the counterweight block. One side of the counterweight block is fixedly connected to the counterweight slider, and the counterweight slider is connected to the counterweight block guide rail so as to be able to reciprocate in the vertical direction; The transverse guide rail is a symmetrical structure, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit is located coincides with the symmetry plane of the transverse guide rail. The longitudinal guide rail is a symmetrical structure, and the vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the tool holder unit is located coincides with the symmetry plane of the longitudinal guide rail. It also includes a spindle drive device for driving the spindle unit to move horizontally and reciprocatingly, which is installed on the top of the bed. When the spindle drive device drives the spindle unit to move, the direction of the line of action of the driving force generated by the spindle drive device coincides with the movement trajectory of the center of gravity of the spindle unit; It also includes a tool holder driving device for driving the tool holder unit to move vertically back and forth, which is installed on the side of the bed. When the tool holder driving device drives the tool holder unit to move, the direction of the line of action of the driving force generated by the tool holder driving device coincides with the movement trajectory of the center of gravity of the tool holder unit; Both sides of the spindle unit include connecting parts, which are connected to the transverse guide rails. The connecting parts are located in the middle of the side of the spindle unit. The spindle unit is suspended at the top opening of the bed.

2. A center-of-gravity driven zero overhang CNC lathe according to claim 1, characterized in that: The bed is a hexahedral structure symmetrical along the vertical direction, with a rectangular cavity structure inside, and the top surface and four side surfaces are all connected to the outside.

3. A center-of-gravity driven zero overhang CNC lathe according to claim 1, characterized in that: The transverse guide rails are two mutually parallel horizontal guide rails, which are symmetrically fixed on the top of the bed. The vertical plane where the trajectory generated by the horizontal movement of the center of gravity of the spindle unit is located coincides with the symmetry plane of the two horizontal guide rails.

4. The center-of-gravity driven zero overhang CNC lathe according to claim 1, characterized in that: The spindle unit comprises a spindle box, a spindle, and a spindle chuck. The spindle box is slidably connected to the transverse guide rail, the spindle passes through the spindle box and is fixed on the spindle box, and the spindle chuck is installed at the lower end of the spindle.

5. The center-of-gravity driven zero overhang CNC lathe according to claim 1, characterized in that: The longitudinal guide rails are two vertical guide rails parallel to each other, symmetrically fixedly installed on the side of the bed, and the vertical plane where the trajectory generated by the vertical movement of the center of gravity of the tool holder unit is located coincides with the symmetry plane of the two vertical guide rails.

6. The center-of-gravity driven zero overhang CNC lathe according to claim 1, characterized in that: The tool holder unit comprises a tool holder box, a tool holder and a tool. The tool holder box can be slidably connected to the longitudinal guide rail, the tool holder is fixed on the tool holder box, and the tool is fixed on the tool holder.

7. The center-of-gravity driven zero overhang CNC lathe according to claim 1, characterized in that: It also includes a base, and the bed is detachably mounted on the base.

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