Z-axis movement driving structure of vertical machine tool

Abstract

The utility model relates to a Z-axis movement driving structure of a vertical machine tool, which comprises a mounting bottom plate, a spindle mounting seat, an electric spindle, a driving motor, a Z-direction guide rail and a balance cylinder, the Z-direction guide rail is fixed on the mounting bottom plate, and the spindle mounting seat is slidably mounted on the Z-direction guide rail and can move up and down along the Z-direction guide rail under the action of the driving motor. The driving motor is mounted on the mounting bottom plate; the electric main shaft is mounted on the main shaft mounting seat; the two balance cylinders are arranged on the two sides of the motorized spindle respectively, cylinder bodies of the balance cylinders are connected with the mounting bottom plate, and cylinder rods are connected with the spindle mounting seat; positive pressure air is introduced into the balance air cylinder to provide upward pulling force. The balance cylinder is arranged on the Z-axis moving structure, so that the load rate of the Z-axis linear motor during Z-axis reciprocating motion is effectively reduced, a reverse gap is eliminated, and the machining precision of a machine tool can be effectively ensured.

Description

Technical Field

[0001] The utility model belongs to the field of numerical control machine tools, and in particular relates to a Z-axis moving drive structure of a vertical machine tool. Background Art

[0002] Linear motors have the advantages of fast response speed and no mechanical wear. As a "zero transmission" system, linear motor drive systems theoretically have no backlash, so they are often used in high-precision CNC machine tools. However, for vertical machine tools, since the Z-axis (spindle) moves vertically, under the action of gravity, the load rate of the drive motor fluctuates greatly during its reciprocating motion, which affects the machining accuracy of the machine tool to a certain extent. In addition, due to factors such as drive stiffness and mechanical structure, there is often a certain amount of backlash even when driven by a linear motor, which restricts the further improvement of the machine tool accuracy. Summary of the invention

[0003] The utility model aims to overcome the deficiencies of the prior art and provide a vertical machine tool Z-axis moving drive structure with small load fluctuation and no backlash, so as to effectively ensure the machining accuracy of the machine tool.

[0004] In order to solve the above technical problems, the utility model is implemented through the following technical solutions: a Z-axis moving drive structure of a vertical machine tool, including a mounting base, a spindle mounting seat, an electric spindle, a driving motor, a Z-guide rail and a balancing cylinder, the Z-guide rail is fixed to the mounting base, the spindle mounting seat is slidably installed on the Z-guide rail, and can move up and down along the Z-guide rail under the action of the driving motor, and the driving motor is installed on the mounting base; the electric spindle is installed on the spindle mounting seat; two balancing cylinders are respectively arranged on both sides of the electric spindle, the cylinder body of the balancing cylinder is connected to the mounting base, and the cylinder rod is connected to the spindle mounting seat; positive pressure gas is introduced into the balancing cylinder to provide upward pulling force.

[0005] In the Z-axis moving drive structure of the vertical machine tool, the upward pulling force provided by the balancing cylinder can balance the gravity of the electric spindle and the spindle mounting seat.

[0006] The above-mentioned Z-axis moving drive structure of the vertical machine tool, the cylinder rod of the balancing cylinder is connected to the spindle mounting seat through a floating joint and a cylinder connecting plate, the cylinder connecting plate is fixed on the spindle mounting seat, one end of the floating joint is connected to the cylinder rod of the balancing cylinder, and the other end is connected to the cylinder connecting plate.

[0007] In the Z-axis moving drive structure of the vertical machine tool, the cylinder body of the balancing cylinder is connected to the mounting base plate through a cylinder mounting frame, the cylinder mounting frame is fixed to the mounting base plate, and the cylinder body of the balancing cylinder is mounted on the cylinder mounting frame.

[0008] In the Z-axis moving drive structure of the vertical machine tool, a trunnion is provided between the cylinder body of the balancing cylinder and the cylinder mounting frame.

[0009] In the above-mentioned Z-axis moving drive structure of a vertical machine tool, the two balancing cylinders are connected to the same pneumatic system, and the pneumatic system includes an air source, a pressure reducing valve and an air storage tank. The pressure reducing valve is connected between the air source and the air storage tank, and the air storage tank is connected to the two balancing cylinders respectively through two quick-plug connectors.

[0010] The Z-axis moving drive structure of the above-mentioned vertical machine tool is also provided with a brake guide rail on the mounting base; a brake is provided on the spindle mounting seat, the brake includes a guide rail clamp and a clamp mounting frame, the clamp mounting frame is fixed on the spindle mounting seat, and the guide rail clamp is installed on the clamp mounting frame; the guide rail clamp can clamp or release the brake guide rail.

[0011] The Z-axis moving drive structure of the above-mentioned vertical machine tool is also provided with a position detection device, including a grating scale, a grating reading head and a reading head mounting frame. The grating scale is installed on the mounting base, the grating reading head is installed on the reading head mounting frame, and the reading head mounting frame is fixed on the spindle mounting seat and can move up and down with the spindle mounting seat.

[0012] In the Z-axis moving drive structure of the above-mentioned vertical machine tool, the drive motor is a linear motor, including a motor primary and a motor secondary, the motor secondary is installed on the mounting base, and the motor primary is connected to the spindle mounting seat.

[0013] Compared with the prior art, the utility model has the following beneficial effects: the utility model sets a balancing cylinder on the Z-axis moving structure, uses the pulling force provided by the balancing cylinder to offset the weight of the Z-axis moving parts, reduces the load rate of the Z-axis linear motor during the reciprocating motion of the Z-axis, improves the dynamic response performance of the system, and reduces the heat generation of the linear motor, thereby improving the accuracy of the machine tool. In addition, the utility model sets a trunnion and a floating joint between the balancing cylinder and the structural parts, and distinguishes the form of the Z-axis working guide rail and the brake guide rail, thereby reducing the structural deformation of the balancing device and the brake device caused by the change of mechanical force during the working process, and further improves the accuracy of the machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram provided by an embodiment of the utility model.

[0015] Figure 2 It is a schematic diagram of the structure of the braking device provided by an embodiment of the utility model.

[0016] Figure 3 It is a schematic diagram of the structure of the pneumatic system provided by an embodiment of the utility model. Implementation

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0018] In the description of the embodiments of the present utility model, it should be noted that the terms "front", "rear", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the embodiments of the present utility model. In addition, unless otherwise clearly specified and limited, the terms "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present utility model can be understood according to specific circumstances.

[0019] Combination Figure 1 and Figure 2 As shown, a Z-axis moving drive structure of a vertical machine tool provided by an embodiment of the utility model includes a mounting base plate 1, a Z-guide rail 2, a spindle mounting seat 3, an electric spindle 4 and a linear motor 6. The Z-guide rail 2 is fixed on the mounting base plate 1, and the spindle mounting seat 3 acts on the Z-guide rail 2 through a slider 5. The slider 5 is fixed to the spindle mounting seat 3 and slidably cooperates with the Z-guide rail 2, and the electric spindle 4 is mounted on the spindle mounting seat 3. The linear motor 6 includes a motor primary 61 and a motor secondary 62. The motor primary 61 is connected to the spindle mounting seat 3, and the motor secondary 62 is mounted on the mounting base plate 1. The interaction between the motor primary 61 and the motor secondary 62 can drive the spindle mounting seat 3 to move up and down along the Z-guide rail 2, thereby realizing the Z-direction reciprocating motion of the electric spindle 4.

[0020] In order to obtain the precise position of the Z-axis movement, a position detection device is also provided, including a grating scale 16, a grating reading head 17 and a reading head mounting frame 18. The grating scale 16 is mounted on the mounting base 1, and the grating reading head 17 is mounted on the reading head mounting frame 18. The reading head mounting frame 18 is fixed on the spindle mounting seat 3 and can move up and down with the spindle mounting seat 3. The precise position feedback of the Z-axis is achieved through the relative movement between the grating reading head 17 and the grating scale 16.

[0021] In order to ensure the safety of the Z axis when it is not in operation or when the power is accidentally cut off, a braking device is also provided, including a braking guide rail 13, a guide rail clamp 14 and a clamp mounting frame 15. The braking guide rail 13 is fixed to the side of the mounting base 1, the clamp mounting frame 15 is fixed to the spindle mounting seat, and the guide rail clamp 14 is mounted on the clamp mounting frame 15. When the machine tool is in the shutdown state or the power is accidentally cut off, the guide rail clamp 14 is in the closed state, holding the braking guide rail 13 tightly to brake and fix the position of the Z axis; when the machine tool is in the working state, the guide rail clamp 14 is in the open state, and the Z axis can move normally.

[0022] In order to reduce the load rate of the linear motor during the reciprocating motion of the Z axis, a balancing cylinder 8 is also provided on both sides of the electric spindle 4. The cylinder body 81 of the balancing cylinder 8 is installed on the mounting base plate 1 through the cylinder mounting frame 7, wherein the cylinder mounting frame 7 is fixed on the mounting base plate 1, and the cylinder body 81 is installed on the cylinder mounting frame 7. The cylinder rod 82 of the balancing cylinder 8 is connected to the spindle mounting seat 3 through the cylinder connecting plate 11, the cylinder connecting plate 11 is fixed on the spindle mounting seat 3, and the cylinder rod 82 is connected to the cylinder connecting plate 11. In order to reduce the influence of the assembly error between the balancing cylinder 8 and the Z guide rail 2 on the posture of the electric spindle 4, an ear shaft 9 is provided between the cylinder body 81 and the cylinder mounting frame 7, and a floating joint 10 is provided between the cylinder rod 82 and the cylinder connecting plate 11, and one end of the floating joint 10 is connected to the cylinder rod 82, and the other end is connected to the cylinder connecting plate 11. Each cylinder body 81 is also provided with a quick-connect connector 12 for connecting to a pneumatic system. Positive pressure gas is introduced into the cylinder body 81 through the pneumatic system to provide an upward pulling force to offset the gravity of the electric spindle 4, the spindle mounting seat 3 and other supporting parts, thereby reducing the load rate of the linear motor.

[0023] In order to ensure that the pulling force provided on both sides of the electric spindle 4 is the same and prevent deformation caused by uneven force on both sides, the embodiment of the utility model adopts the same pneumatic system for air supply, that is, the two balancing cylinders 8 are connected to the same pneumatic system.

[0024] like Figure 3 As shown, the pneumatic system provided by the embodiment of the utility model includes an air source 19, a filter pressure reducing valve 20, a precision pressure reducing valve 21 and an air storage tank 22. The air source 19, the filter pressure reducing valve 20 and the precision pressure reducing valve 21 are connected in sequence. The air storage tank 22 is arranged between the precision pressure reducing valve 21 and the balancing cylinder 8. The total volume of gas contained therein is increased to stabilize the air pressure, reduce the air pressure fluctuation caused by insufficient exhaust or air replenishment speed of the precision pressure reducing valve 21 when the Z-axis of the machine tool reciprocates at high speed, and improve the thrust stability of the linear motor.

[0025] The function of the precision pressure reducing valve 21 is to accurately adjust the air pressure of the supplied air. For the air pressure setting value of the precision pressure reducing valve 21, the embodiment of the utility model is set according to the total pulling force provided by the balancing cylinder being slightly less than or slightly greater than the total weight of the electric spindle 4, the spindle mounting seat 3 and other supporting parts, that is, not completely offsetting the total weight of the Z-axis moving assembly. According to this setting, the Z-axis moving assembly can enable the drive motor 6 to always maintain a stable thrust during the movement, thereby improving the driving rigidity of the Z-axis and reducing the reverse clearance of the axis.

[0026] Although the utility model is described in detail above, the utility model is not limited thereto, and those skilled in the art can make various modifications according to the principle of the utility model. Therefore, all modifications made according to the principle of the utility model should be understood to fall within the protection scope of the utility model.

Claims

1. A Z-axis moving drive structure of a vertical machine tool, characterized in that: It includes a mounting base, a spindle mounting seat, an electric spindle, a driving motor, a Z-guide rail and a balancing cylinder. The Z-guide rail is fixed on the mounting base, and the spindle mounting seat is slidably mounted on the Z-guide rail and can move up and down along the Z-guide rail under the action of the driving motor. The driving motor is mounted on the mounting base; the electric spindle is mounted on the spindle mounting seat; two balancing cylinders are respectively arranged on both sides of the electric spindle, the cylinder body of the balancing cylinder is connected to the mounting base, and the cylinder rod is connected to the spindle mounting seat; positive pressure gas is introduced into the balancing cylinder to provide upward pulling force.

2. The Z-axis moving drive structure of a vertical machine tool according to claim 1, characterized in that: The upward pulling force provided by the balancing cylinder can be balanced with the gravity of the electric spindle and the spindle mounting seat.

3. The Z-axis moving drive structure of a vertical machine tool according to claim 1 or 2, characterized in that: The cylinder rod of the balancing cylinder is connected to the main shaft mounting seat through a floating joint and a cylinder connecting plate. The cylinder connecting plate is fixed on the main shaft mounting seat. One end of the floating joint is connected to the cylinder rod of the balancing cylinder, and the other end is connected to the cylinder connecting plate.

4. The Z-axis moving drive structure of a vertical machine tool according to claim 3, characterized in that: The cylinder body of the balancing cylinder is connected to the mounting base plate through a cylinder mounting frame, the cylinder mounting frame is fixed on the mounting base plate, and the cylinder body of the balancing cylinder is mounted on the cylinder mounting frame.

5. The Z-axis moving drive structure of a vertical machine tool according to claim 4, characterized in that: A trunnion is arranged between the cylinder body of the balancing cylinder and the cylinder mounting frame.

6. The Z-axis moving drive structure of a vertical machine tool according to claim 5, characterized in that: The two balancing cylinders are connected to the same pneumatic system, which includes an air source, a pressure reducing valve and an air storage tank. The pressure reducing valve is connected between the air source and the air storage tank, and the air storage tank is connected to the two balancing cylinders respectively through two quick-connect connectors.

7. The Z-axis moving drive structure of a vertical machine tool according to claim 6, characterized in that: The mounting base is also provided with a brake rail; the main shaft mounting seat is provided with a brake, the brake comprises a rail clamp and a clamp mounting frame, the clamp mounting frame is fixed on the main shaft mounting seat, and the rail clamp is mounted on the clamp mounting frame; the rail clamp can clamp or release the brake rail.

8. The Z-axis moving drive structure of a vertical machine tool according to claim 7, characterized in that: A position detection device is also provided, including a grating ruler, a grating reading head and a reading head mounting frame. The grating ruler is mounted on the mounting base, the grating reading head is mounted on the reading head mounting frame, and the reading head mounting frame is fixed on the spindle mounting seat and can move up and down with the spindle mounting seat.

9. The Z-axis moving drive structure of a vertical machine tool according to claim 8, characterized in that: The driving motor is a linear motor, including a motor primary and a motor secondary. The motor secondary is installed on the mounting base plate, and the motor primary is connected to the spindle mounting seat.

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