Double linear motor driven EDM spindle structure

Abstract

The present invention discloses a dual linear motor driven EDM spindle structure, comprising a spindle, the spindle comprising a spindle housing, a cylinder barrel mounted on the top surface of the spindle housing, one end of a mounting seat in the spindle housing extending from a side opening of the spindle housing and then fixed to a spindle mounting column, one end of a piston rod placed in the cylinder barrel and the other end passing through the spindle housing and then fixed to the top surface of the mounting seat, two side walls of the mounting seat respectively opposite to the two side walls of the spindle housing and a linear motor mounted between the opposite side walls of the mounting seat and the side walls of the spindle housing, a heat sink mounted on the side of the linear motor in contact with the side wall of the mounting seat, a fixture mounted on the bottom surface of the spindle housing, two vertical edges of a side opening formed on the spindle housing are mounted with slide rails, and the slide rails are slidably connected to a spindle slider on the spindle mounting column. The present invention drives the spindle by dual linear motors and pneumatically balances the weight of the spindle, and can effectively heat the linear motor to ensure that the spindle has high responsiveness, high control accuracy and other performances.

Description

Technical Field

[0001] The invention relates to a dual linear motor driven electric spark machining spindle structure, belonging to the field of electric spark machining spindles. Background Art

[0002] At present, most of the domestic EDM equipment is driven by the structure of "rotating motor + ball screw". This structure involves many parts and has a large motion inertia. The linear velocity, acceleration and positioning accuracy generated by the ball screw are all limited. With the rapid development of technology, ultra-high-speed and ultra-precision EDM has put forward higher requirements for the driving method. The above-mentioned traditional driving methods are difficult to meet the requirements due to the shortcomings of long transmission chain, large size, low efficiency, high energy consumption and poor precision. In addition, due to the effect of gravity, the traditional driving method requires hydraulic counterweighting of the spindle, and the way the counterweight block is connected to the spindle will bring inertial impact to the spindle, which greatly affects the stability of the system.

[0003] Linear motor, also known as linear motor, is a transmission device that directly converts electrical energy into mechanical energy. It has the characteristics of simple structure, large starting thrust, high transmission stiffness, fast dynamic response, large speed and acceleration, and high positioning accuracy. It is an ideal transmission device for ultra-high-speed and ultra-precision EDM. If linear motors are applied to EDM machine tools, the speed and acceleration can be greatly improved, thereby improving the processing efficiency and processing accuracy, and improving stability.

[0004] However, during the EDM process, the spindle needs to discharge repeatedly at high frequency, generating high heat, which will have a certain impact on the response speed, motion accuracy and other performance of the linear motor. Therefore, the requirements for the heat dissipation performance of the linear motor are relatively high. At present, there is no relatively mature technology for the application of linear motors in EDM machine tools. Summary of the invention

[0005] The purpose of the present invention is to provide a dual linear motor driven EDM spindle structure, which drives the spindle through dual linear motors, pneumatically balances the spindle weight, and provides effective heat dissipation protection for the linear motor, thereby ensuring that the spindle has high responsiveness, high control accuracy and other performance.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A dual linear motor driven EDM spindle structure, characterized in that: it includes a spindle mounted on a spindle mounting column, wherein: the spindle includes a rectangular spindle housing with a side opening, a cylinder barrel is mounted on the top surface of the spindle housing, one end of a rectangular mounting seat in the spindle housing extends from the side opening of the spindle housing and is fixed to the spindle mounting column, one end of a piston rod is placed in the cylinder barrel and the other end passes through the spindle housing and is fixed to the top surface of the mounting seat, and two side walls of the mounting seat are respectively opposite to the two side walls of the spindle housing and are opposite to each other. A linear motor is installed between the side wall of the mounting seat and the side wall of the spindle housing, a heat sink is installed on the side of the linear motor that contacts the side wall of the mounting seat, a fixture is installed on the bottom of the spindle housing, and slide rails are installed on the two vertical edges forming the side opening on the spindle housing, and the slide rails are connected to the spindle slider fixed on the spindle mounting column for up and down sliding; driven by two linear motors, the spindle housing, cylinder barrel and fixture make up and down linear motion together by the relative sliding between the slide rails and the spindle slider, and at the same time, the piston rod makes up and down piston motion in the cylinder barrel.

[0008] The advantages of the present invention are:

[0009] On the one hand, the present invention adopts two linear motors to drive the spindle, so that the spindle has excellent speed, acceleration, motion accuracy and control accuracy. On the other hand, a pneumatic method is used to balance the weight of the spindle, reduce inertial impact, and improve the response ability and rigidity of the spindle. In addition, the present invention effectively dissipates heat from the linear motor through a heat sink and circulating cooling water to ensure that the linear motor can exert its own characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the composition of the dual linear motor driven EDM spindle structure of the present invention.

[0011] Figure 2 yes Figure 1 AA section diagram of .

[0012] Figure 3 It is a three-dimensional schematic diagram of the mounting base.

[0013] Figure 4 yes Figure 1 An enlarged schematic diagram of the mount shown. DETAILED DESCRIPTION

[0014] like Figures 1 to 4As shown, the dual linear motor driven EDM spindle structure of the present invention includes a spindle mounted on a spindle mounting column 100, and the spindle mounting column 100 is fixed on the EDM machine tool, wherein: the spindle includes a rectangular spindle housing 20 with a side opening, a cylinder barrel 10 with a lower opening is installed on the top surface of the spindle housing 20, one end of the rectangular mounting seat 40 in the spindle housing 20 extends from the side opening of the spindle housing 20 and is fixed to the spindle mounting column 100, one end of the piston rod 70 is placed in the cylinder barrel 10 and the other end passes through the spindle housing 20 and is fixed to the top surface of the mounting seat 40 On the upper side, the two side walls of the mounting seat 40 are respectively opposite to the two side walls of the spindle housing 20, and a linear motor 30 is installed between the opposite side walls of the mounting seat 40 and the side walls of the spindle housing 20. A heat sink 50 is installed on the side of the linear motor 30 that contacts the side wall of the mounting seat 40. A clamp 80 is installed on the bottom surface of the spindle housing 20. Two vertical edges of the side opening are formed on the spindle housing 20, that is, the two opposite side walls on the spindle housing 20 are located on the two vertical edges of the side opening. The vertical slide rail 61 is connected to the spindle slider 62 fixed on the spindle mounting column 100 for sliding up and down, as shown in FIG. Figure 1 and Figure 2 , the figure shows that each slide rail 61 is equipped with two upper and lower spindle sliders 62; driven by two linear motors 30, the spindle housing 20, the cylinder barrel 10 and the clamp 80 make up and down linear motions through the relative sliding between the slide rail 61 and the spindle slider 62, and at the same time, the piston rod 70 makes up and down piston motions in the cylinder barrel 10.

[0015] like Figure 1 and Figure 2 The spindle housing 20 is composed of a top plate 21, a bottom plate 23, an end plate 22 and two side plates 24. The two side plates 24 serving as side walls are opposite to each other. The sides of the two side plates 24 are respectively two vertical edges forming a side opening. The end plate 22 forming an end surface is opposite to the side opening. Among them: a through hole 210 for the piston rod 70 to pass through is opened on the top plate 21. The lower end of the piston rod 70 extending from the cylinder barrel 10 passes through the through hole 210 and is screwed into a preset mounting hole 46 on the top surface of the mounting seat 40. The upper end of the piston rod 70 divides the cylinder barrel 10 into upper and lower chambers isolated from each other. The upper chamber is sealed, and the lower chamber is connected to the outside through the through hole 210 and the side opening to achieve pneumatic balance of the spindle. A mounting hole for screwing the clamp 80 is preset on the bottom plate 23.

[0016] like Figure 2 The linear motor 30 includes a motor slider 32 and a motor guide rail 31. The motor guide rail 31 is fixed in the side wall of the spindle housing 20. Figure 2 The figure shows that the motor guide rail 31 is embedded on the inner surface of the side plate 24 of the spindle housing 20 , the motor slider 32 is fixed on the side wall of the mounting seat 40 , and the heat sink 50 is interposed between the motor slider 32 and the side wall of the mounting seat 40 .

[0017] In the present invention, the two linear motors 30 are installed back to back.

[0018] In the art, the linear motor 30 is an existing device, and the motor slider 32 thereon can slide along the motor guide rail 31. In addition to the motor slider 32 and the motor guide rail 31, the linear motor 30 also has other components, which will not be described in detail here.

[0019] like Figure 3 and Figure 4 The mounting seat 40 includes a rectangular frame 41, a mounting hole 46 for fixing the piston rod 70 is preset on the top surface of the frame 41, a groove 44 is concavely provided on the side of the frame 41 as the side wall of the mounting seat 40, and the heat sink 50 is placed in the groove 44. The end surface of the frame 41 fixed to the spindle mounting column 100 extends up and down respectively, and connecting plates 45 are conducive to firmly fixing the mounting seat 40.

[0020] like Figure 3 and Figure 4 A circulation chamber 410 is provided in the frame 41 of the mounting seat 40, and a water inlet 42 and a water outlet 43 are provided on the end surface of the frame 41 fixed to the spindle mounting column 100, the water inlet 42 is at the bottom, and the water outlet 43 is at the top, and the water inlet 42 and the water outlet 43 are connected to the circulation chamber 410.

[0021] like Figure 1 The spindle mounting column 100 includes a column housing 102 having an inner cavity 103. Figure 1 The column housing 102 is shown to be L-shaped (not limited thereto), and a water inlet hole 101 and a water outlet hole 104 are provided at the portion where the column housing 102 is fixed to the mounting seat 40. The water inlet hole 101 and the water outlet hole 104 are respectively opposite to and connected with the water inlet 42 and the water outlet 43 on the mounting seat 40.

[0022] During actual installation, the water inlet hole 101 and the water outlet hole 104 on the spindle mounting column 100 are respectively connected to the water outlet port and the water inlet port of a cooling water circulation supply device (existing equipment, not shown in the figure) placed in the inner cavity 103, so as to dissipate the heat of the linear motor 30 through the circulating cooling water and the heat conduction effect of the mounting base 40.

[0023] like Figure 2 A grating ruler 90 for measuring the vertical displacement of the spindle is vertically installed on the spindle mounting column 100.

[0024] In practical applications, the linear motor 30 is connected to a control device (a well-known device) and is controlled by the control device.

[0025] The working process of the dual linear motor driven EDM spindle structure of the present invention is as follows:

[0026] During processing, the workpiece to be processed is fixed on the fixture 80, and the control device controls the two linear motors 30 to move synchronously, that is, the motor slider 32 slides up and down along the motor guide rail 31. Therefore, under the drive of the two linear motors 30, the spindle housing 20, the cylinder barrel 10 and the fixture 80 make up and down linear motions together through the relative sliding between the slide rail 61 and the spindle slider 62, thereby performing the processing operation.

[0027] In the present invention, the back-to-back installation of the two linear motors 30 makes the spindle movement stable and reliable, and the processing quality is guaranteed.

[0028] Since the mounting seat 40 is fixed on the spindle mounting column 100, and the lower end of the piston rod 70 is fixed on the mounting seat 40, the piston rod 70 performs piston movement in the cylinder barrel 10 in the up and down directions by means of the up and down linear movement of the spindle housing 20 and the cylinder barrel 10. Since the lower chamber separated by the piston rod 70 in the cylinder barrel 10 is connected to the outside through the through hole 210 and the side opening, the overall weight of the spindle is pneumatically balanced by the cylinder barrel 10, reducing the inertial impact of the spindle and improving the response capability and stiffness of the spindle.

[0029] During the processing, the cooling water circulation supply device delivers cooling water, which is injected into the circulation cavity 410 of the mounting seat 40 through the water inlet hole 101 and the water inlet port 42, and then flows back to the cooling water circulation supply device through the water outlet 43 and the water outlet hole 104, thereby achieving heat dissipation for the linear motor 30 based on the circulating cooling water.

[0030] The advantages of the present invention are:

[0031] 1. The present invention adopts a driving mode of two linear motors installed back to back for the spindle on the EDM machine tool, which improves the dynamic load-bearing capacity and thermal structure stability of the spindle, improves the servo discharge machining performance, and has high operating reliability. The linear motor does not require transmission devices such as transmission chains as intermediate transmissions, and avoids frictional contact. Compared with the traditional spindle, the linear motor enables the spindle to have higher speed, acceleration, motion accuracy, control accuracy and other performances, thereby improving the machining efficiency and machining accuracy.

[0032] 2. The present invention adopts pneumatic balancing to balance the weight of the spindle. The linear motor replaces the traditional hydraulic counterweight method, which effectively ensures the balance between the spindle and the inertial load, minimizes the inertial impact, effectively improves the rapid response capability of the spindle, and improves the rigidity of the spindle. When an unexpected situation occurs, the spindle can be stopped in time to ensure the safety of the system.

[0033] 3. The present invention is equipped with a heat sink, and can effectively dissipate the heat of the linear motor through circulating cooling water, thereby ensuring that the spindle can smoothly perform high-frequency repeated discharge machining operations, increasing the stability of the machine tool and ensuring machining accuracy.

[0034] 4. The present invention is suitable for ultra-high-speed and ultra-precision EDM machines, especially moving-beam gantry EDM machines, which can not only obtain high acceleration characteristics, but also avoid torsion swing of the gantry structure, thus meeting the requirements of high-precision servo processing.

[0035] The above are preferred embodiments of the present invention and the technical principles used therein. For those skilled in the art, any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, are within the scope of protection of the present invention.

Claims

1. A dual linear motor driven EDM spindle structure, characterized in that: It includes a spindle installed on a spindle mounting column, wherein: the spindle includes a rectangular spindle housing with a side opening, a cylinder barrel is installed on the top surface of the spindle housing, one end of a rectangular mounting seat in the spindle housing extends out from the side opening of the spindle housing and is fixed to the spindle mounting column, one end of a piston rod is placed in the cylinder barrel and the other end passes through the spindle housing and is fixed to the top surface of the mounting seat, two side walls of the mounting seat are respectively opposite to the two side walls of the spindle housing and a linear motor is installed between the opposite side walls of the mounting seat and the side walls of the spindle housing, a heat dissipation plate is installed on the side of the linear motor that contacts the side wall of the mounting seat, a clamp is installed on the bottom surface of the spindle housing, slide rails are installed on the two vertical edges forming the side opening on the spindle housing, and the slide rails are connected to the spindle slider fixed on the spindle mounting column for upward and downward sliding movement. The invention relates to a method for manufacturing a linear actuator for the spindle housing, wherein the spindle housing, the cylinder barrel and the fixture perform linear up and down motions by relative sliding between the slide rail and the spindle slider, and the piston rod performs piston motions up and down in the cylinder barrel. The linear motor comprises a motor slider and a motor guide rail, wherein the motor guide rail is fixed in the side wall of the spindle housing, the motor slider is fixed on the side wall of the mounting seat, and the heat sink is located between the motor slider and the side wall of the mounting seat. The mounting seat comprises a rectangular frame, wherein a mounting hole for fixing the piston rod is preset on the top surface of the frame, a groove is concavely arranged on the side surface of the frame as the side wall of the mounting seat, and the heat sink is placed in the groove. A circulation cavity is arranged in the frame of the mounting seat, and a water inlet and a water outlet are arranged on the end surface of the frame fixed to the spindle mounting column, and the water inlet and the water outlet are connected to the circulation cavity.

2. The dual linear motor driven EDM spindle structure as claimed in claim 1, characterized in that: The spindle housing is composed of a top plate, a bottom plate, an end plate and two side plates, the two side plates serving as side walls are opposite to each other, the side edges of the two side plates are respectively two vertical edges forming the side opening, the end plates are opposite to the side opening, wherein: a through hole for the piston rod to pass through is opened on the top plate, the piston rod divides the cylinder barrel into upper and lower chambers, the lower chamber is connected to the outside through the through hole and the side opening.

3. The dual linear motor driven EDM spindle structure according to claim 1, characterized in that: The spindle mounting column includes a column shell with an inner cavity. A water inlet hole and a water outlet hole are opened at the position where the column shell is fixed to the mounting seat. The water inlet hole and the water outlet hole are respectively opposite to and connected with the water inlet and the water outlet on the mounting seat.

4. The dual linear motor driven EDM spindle structure as claimed in claim 3, characterized in that: The water inlet hole and the water outlet hole on the main shaft mounting column are respectively connected to the water outlet port and the water inlet port of the cooling water circulation supply device.

5. The dual linear motor driven EDM spindle structure as claimed in claim 1, characterized in that: A grating ruler is vertically installed on the main shaft installation column.

6. The dual linear motor driven EDM spindle structure according to any one of claims 1 to 5, characterized in that: The linear motor is connected to the control device and is controlled by the control device.

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