High-speed electric spindle with automatic tool change for center hole water flow

Abstract

The middle hole water-through automatic tool-changing high-speed electric spindle includes a housing and a spindle. A pull rod is inserted in the hollow structure of the spindle. A pull claw is connected to the front end of the pull rod. A disc spring is inserted on the pull rod. A sealing locating sleeve is screwed to the other end of the disc spring. A rotary joint is connected to the rear end of the pull rod behind the sealing locating sleeve. The center of the pull rod has a cooling water channel. The center of the cylinder rod of the knife-beating cylinder is a cavity. A pull rod rear support bearing is arranged in the cavity. The knife-beating cylinder is fixedly connected to the rear end of the housing. The air seal ring consists of an outer ring and an inner ring fixed to the outer ring. A support sleeve is fixedly connected to the rear end of the knife-beating cylinder. Two sealing ring grooves are opened in the mounting circular hole of the support sleeve. Sealing rings are installed in the sealing ring grooves. The interference between the rotary joint and the sealing ring is 0.25mm to 0.35mm. After testing, this electric spindle can achieve the performance of similar foreign products.

Description

Technical Field

[0001] The invention relates to an electric spindle, in particular to a high-speed electric spindle capable of automatically changing tools, and belongs to the technical field of mechanical equipment. Background Art

[0002] High-speed electric spindles with a speed of more than 9000r / min are the core basic spare parts of the current CNC machine tool equipment manufacturing industry. This type of electric spindle application must have a hollow water-cooled structure and be able to change tools. At present, this type of electric spindle technology is blocked by foreign countries and basically relies on imports. The import price is expensive, and the main technical obstacles to localization are as follows:

[0003] One is the problem of concentricity; this type of electric spindle is generally composed of an outer shell (also called a housing), a front end cover (also called a sealing cover), a stator installed in the outer shell, a spindle (also a rotor), and a knife-beating mechanism located in the spindle cavity. The spindle is supported in the outer shell by two sets of bearings at the front and back. The knife-beating mechanism is usually a pull rod passed through the hollow spindle, the front end of the pull rod is connected to the rear part of the knife claw, a disc spring is passed through the outside of the pull rod, and the rear ends of the disc springs are respectively pressed against the spindle, and the rear ends of the disc springs are pressed against the rear section of the pull rod (the adjacent sections are connected by threads), and the rear end of the pull rod extends out of the spindle, and a knife-beating cylinder is arranged behind the electric spindle in cooperation with the pull rod, and the pull rod is driven forward by the knife-beating cylinder to complete the knife-beating. A large amount of heat will be generated during the high-speed rotation of the electric spindle. If this heat is not eliminated in time, the resulting temperature rise will cause the spindle to change its axial direction and cause problems with machining accuracy. In order to meet the needs of spindle cooling, a cooling structure is also configured in this knife-beating structure. The cooling structure usually opens an axial Through hole, the rear end of the pull rod is connected to the rotary joint, and the coolant pipeline is connected to the rotary joint. The electric spindle shaft currently used in China basically relies on imports. One of the important reasons why this kind of spindle cannot be produced in China is the concentricity problem. Because the spindle has two sets of front and rear support bearings, and the rear end of the pull rod has a set of rear support bearings. During operation, the spindle and the pull rod rotate synchronously. When cutting, the rear support bearing of the pull rod also needs to move axially, so this place can only be a floating support, and the rear end of the pull rod must be connected to a rotary joint, and the support of the rotary joint also needs to be highly concentric with the spindle. Once there is one or more concentricity differences in these components, obvious vibration will occur when the electric spindle is running at high speed, affecting the machining accuracy of the machine tool, generating a lot of noise, and causing fatigue damage; most of the electric spindles produced by domestic manufacturers can either achieve automatic tool change but not mid-hole water cooling, or can achieve mid-hole water cooling but not automatic tool change under the requirements of high-speed operation;

[0004] Second, when cooling the tool, the cooling water will flow back from the front end into the inside of the electric spindle, causing damage to the electric spindle;

[0005] Third, the insulation resistance of the stator is low;

[0006] Fourth, the main shaft has poor sealing, which can easily lead to water ingress and cause failure;

[0007] Fifth, once the rotary joint is damaged, water can easily enter the inside of the spindle. The above problems will affect the service life and cost-effectiveness of the automatic tool changing high-speed electric spindle. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned problems existing in the current manufacturing of a high-speed electric spindle with automatic tool change and a middle-hole water-through, and to provide a high-speed electric spindle with automatic tool change and a middle-hole water-through.

[0009] To achieve the purpose of the present invention, the following technical scheme is adopted: a high-speed electric spindle with water passing through a center hole and automatic tool changing, comprising a housing, a stator installed in the housing, a spindle with winding wires, a front cover with holes, and a knife-beating cylinder, the spindle passes through the middle of the front cover, and an air sealing ring is installed at the front end of the front cover; the spindle is arranged in the housing through a front support bearing seat and a rear support bearing seat, the spindle is a hollow structure, a pull rod is passed through the hollow structure of the spindle, the pull rod is a multi-section structure, and the multiple sections are connected by threads, the front end of the pull rod is connected to a pull claw, and a disc spring is passed through the pull rod, one end of the disc spring is pressed against the spindle, and the other end of the disc spring is pressed against the spindle. A sealing positioning sleeve is screwed on the part, and the rear end of the pull rod behind the sealing positioning sleeve is connected to a rotary joint. A cooling water channel is provided in the center of the pull rod, and the cooling water channel is connected to the water channel of the rotary joint. The center of the cylinder rod of the knife-beating cylinder is a cavity, and a pull rod rear support bearing is provided in the cavity. The pull rod passes through the pull rod rear support bearing. The knife-beating cylinder is fixedly connected to the rear end of the shell, and the stator has a plastic sealing structure. The air sealing ring consists of an outer ring and an inner ring fixed to the outer ring. An axial gas channel and radial air holes are provided on the outer ring. The radial air holes are connected to the axial gas channel, and the outer inner ring is provided with a plurality of air holes. An annular groove 1 is provided on the circumferential surface, and the annular groove 1 corresponds to the radial air hole position. The radial air hole is radially located outside the annular groove 1. A plurality of radial air distribution holes are provided on the bottom surface of the annular groove 1. The front support bearing seat and the rear support bearing seat are interference fit with the inner cavity of the shell, and the interference amount is 0.005-0.01mm; the pull rod rear support bearing and the cavity are interference fit, and the interference amount is 0.006-0.008; a sealing gasket is installed in the middle of the disc spring, and there are two sealing gaskets; grooves are provided on the outer periphery of the pull claw, the sealing positioning sleeve, and the outer periphery of the sealing gasket. There are two grooves on the outer periphery of the pulling claw and the sealing positioning sleeve, and sealing rings are installed in the grooves. There is an interference fit between the sealing ring and the cavity at this location, and the interference amount is 0.5mm. A mounting circular hole is provided on the rear end surface of the support sleeve fixedly connected to the rear end of the knife cylinder. The diameter of the mounting circular hole is larger than the diameter of the rotary joint. Two sealing ring grooves are provided in the hole, and rotary joint sealing rings are installed in the two sealing ring grooves. There is an interference fit between the rotary joint and the rotary joint sealing ring; the interference amount between the rotary joint and the sealing ring is 0.25mm to 0.35mm.

[0010] Furthermore, an annular groove 2 is provided at the radial air hole on the outer ring, and the position of the annular groove 2 corresponds to that of the annular groove 1.

[0011] Furthermore, the number of the air distribution holes is 4-12.

[0012] Furthermore, the number of the air distribution holes is 8.

[0013] Furthermore, an annular groove three is provided on the inner circumferential surface of the inner ring, and the end of each air distribution hole is located in the annular groove three.

[0014] Furthermore, the single-sided gap between the main shaft and the air sealing ring is 0.02mm.

[0015] Furthermore, the interference between the rotary joint and the sealing ring is 0.3mm.

[0016] Furthermore, the drain outlet of the rotary joint is located outside the support sleeve.

[0017] The positive and beneficial technical effects of the present invention are: interference fit is adopted between the components of the electric spindle, which solves the concentricity problem under the three-support condition. After the electric spindle is assembled, the concentricity can be controlled within 0.01mm, which can meet the requirements of high-speed operation of the electric spindle. The stator plastic sealing solves the problem of low insulation resistance, and the air sealing ring solves the problem of water backflow into the spindle. Each sealing ring can not only ensure good sealing, but also play a role in supporting and ensuring concentricity. The drain outlet of the rotary joint is external, and even if it is damaged, it will not cause water to flow into the electric spindle. After testing, the electric spindle can achieve the performance of similar foreign products, and the selling price can reach one-third of foreign products, which can generate objective profits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an overall schematic diagram of the present invention.

[0019] Figure 2 This is one of the enlarged schematic diagrams of the electric spindle part.

[0020] Figure 3 It is an overall schematic diagram of the electric spindle gas seal ring.

[0021] Figure 4 Schematic diagram of the outer ring of the air seal ring.

[0022] Figure 5 It is a schematic diagram of the inner ring of the air seal ring.

[0023] Figure 6 It is a schematic diagram of the circular surface of the inner ring of the gas seal ring.

[0024] Figure 7 This is the second enlarged schematic diagram of the electric spindle part.

[0025] Figure 8 is a schematic diagram of the support sleeve. DETAILED DESCRIPTION

[0026] In order to more fully explain the implementation of the present invention, embodiments of the present invention are provided. These embodiments are merely elaborations of the present invention and do not limit the scope of the present invention.

[0027] The present invention is further explained in detail in conjunction with the accompanying drawings, in which the marks are: 1: housing; 2: main shaft; 3: front cover; 4: gas sealing ring; 41: axial gas channel; 42: radial air hole; 43: outer ring; 44: inner ring; 45: annular groove 1; 46: air distribution hole; 47: annular groove 2; 48: annular groove 3; 5: front support bearing seat; 6: rear support bearing seat; 7: pull rod; 8: pull claw; 81: sealing ring 1 on the pull claw; 82: sealing ring 2 on the pull claw; 9: disc spring; 10: sealing gasket 1; 101 sealing ring on sealing gasket 1; 11: Sealing gasket 2; 111: Sealing ring on sealing gasket 2; 12: Sealing locating sleeve; 121: Sealing locating sleeve sealing ring 1; 122: Sealing locating sleeve sealing ring 2; 13: Cylinder; 14: Cylinder rod; 15: Rear support bearing of tie rod; 16: Support sleeve; 161: Mounting round hole; 162: Sealing ring groove; 17: Rotary joint; 171: Drainage outlet; 18: Gas passage;

[0028] 19: Stator.

[0029] As shown in the attached drawings, a high-speed electric spindle with automatic tool change and water-through in the center hole comprises a housing 1, a stator 19 installed in the housing, a spindle 2 with a winding, a front cover 3 with a hole, and a knife-beating cylinder 13. The knife-beating cylinder can be a cylinder. A gas passage is processed on the housing 1, and a gas transition channel is also provided on the front cover for guiding the gas to the gas sealing ring relative to the gas passage. The spindle passes through the front cover, and the stator has a plastic sealing structure. A gas sealing ring 4 is installed at the front end of the front cover; the spindle is arranged in the housing through a front supporting bearing seat 5 and a rear supporting bearing seat 6. The spindle is a hollow structure, and a pull rod 7 is passed through the hollow structure of the spindle. The pull rod is The structure is multi-section, and the sections are connected by threads. The front end of the pull rod is connected with a pull claw 8, and a disc spring 9 is inserted on the pull rod. One end of the disc spring is pressed against the spindle, and the other end of the disc spring is screwed with a sealing locating sleeve 12. The rear end of the pull rod behind the sealing locating sleeve is connected with a rotary joint 17. The center of the pull rod has a cooling water channel, and the cooling water channel is connected to the water channel of the rotary joint. The center of the cylinder rod of the knife-beating cylinder is a cavity, and a pull rod rear support bearing 15 is provided in the cavity. The pull rod passes through the pull rod rear support bearing, and the knife-beating cylinder 13 is fixedly connected to the rear end of the shell. The above is the structure of the existing low-speed electric spindle. The stator has a plastic sealing structure. Plastic sealing can effectively prevent the reduction of its insulation resistance.

[0030] The air sealing ring 4 is composed of an outer ring 43 and an inner ring 44 fixed to the outer ring. An axial gas channel 41 and radial air holes 42 are provided on the outer ring. The radial air holes are connected to the axial gas channel. An annular groove 45 is provided on the outer circumferential surface of the inner ring. The annular groove 45 corresponds to the position of the radial air holes. The radial air holes are radially located outside the annular groove 43. A plurality of radial air distribution holes 46 are provided on the bottom surface of the annular groove 43. Furthermore, the number of air distribution holes is 4-12. More specifically, in this embodiment, the number of air distribution holes is 8. The 8 air distribution holes are as follows: Figure 6 As shown, an annular groove 2 is opened at the radial air hole on the outer ring, and the position of annular groove 2 corresponds to that of annular groove 1. An annular groove 3 is opened on the inner circumferential surface of the inner ring, and the ends of each air distribution hole are located in annular groove 3. The single-sided gap between the main shaft and the air sealing ring is 0.02mm. The structure and gap design of the air sealing ring can effectively prevent water from flowing back into the electric spindle.

[0031] The front support bearing seat 5 and the rear support bearing seat 6 are interference fit with the inner cavity of the shell, and the interference amount is 0.005-0.01mm; the pull rod rear support bearing 15 is interference fit with the cavity, and the interference amount is 0.006-0.008; a sealing gasket is installed in the middle of the disc spring, and there are two sealing gaskets, as shown in 10 and 11, and grooves are opened on the outer periphery of the pull claw, the sealing positioning sleeve, and the outer periphery of the sealing gasket, and sealing rings are sleeved in the grooves, and grooves are opened on the outer periphery of the pull claw, the sealing positioning sleeve, and the outer periphery of the sealing gasket, and sealing rings are sleeved in the grooves. The sealing rings on the two sealing gaskets are shown in 101 As shown in 111, the two sealing rings on the pull claw are shown in 81 and 82, and there is an interference fit between the sealing ring and the cavity therein, and the interference amount is 0.5mm. The rear end of the cylinder is fixedly connected with the support sleeve 16, and a mounting circular hole 161 is opened on the rear end face. The diameter of the mounting circular hole is larger than the diameter of the rotary joint. Two sealing ring grooves begin in the hole, and the two sealing grooves are shown in 162. Rotary joint sealing rings are installed in both sealing ring grooves. There is an interference fit between the rotary joint 14 and the rotary joint sealing ring; the interference amount between the rotary joint and the sealing ring is 0.25mm to 0.35mm. In this example, the interference amount between the rotary joint and the sealing ring is 0.3mm. The drain port of the rotary joint is located outside the support sleeve. This mounting support structure of the rotary joint can ensure concentricity and effective support, and does not affect the axial movement of the rotary joint with the pull rod. The design here is an important part of this main shaft.

[0032] After describing the implementation mode of the present invention in detail, people familiar with the technology can clearly understand that various changes and modifications can be made without departing from the scope and spirit of the above-mentioned patent application. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention, and the present invention is not limited to the implementation mode of the examples given in the specification.

[0033] The middle hole water-through automatic tool-changing high-speed electric spindle includes a housing and a spindle. A pull rod is inserted in the hollow structure of the spindle. A pull claw is connected to the front end of the pull rod. A disc spring is inserted on the pull rod. A sealing locating sleeve is screwed to the other end of the disc spring. A rotary joint is connected to the rear end of the pull rod behind the sealing locating sleeve. The center of the pull rod has a cooling water channel. The center of the cylinder rod of the knife-beating cylinder is a cavity. A pull rod rear support bearing is arranged in the cavity. The knife-beating cylinder is fixedly connected to the rear end of the housing. The air seal ring consists of an outer ring and an inner ring fixed to the outer ring. A support sleeve is fixedly connected to the rear end of the knife-beating cylinder. Two sealing ring grooves are opened in the mounting circular hole of the support sleeve. Sealing rings are installed in the sealing ring grooves. The interference between the rotary joint and the sealing ring is 0.25mm to 0.35mm. After testing, this electric spindle can achieve the performance of similar foreign products.

Claims

1. A high-speed electric spindle with automatic tool change and water passing through a center hole, comprising a housing, a stator installed in the housing, a spindle with a winding, a front cover with a hole, and a knife-beating cylinder. The spindle passes through the center of the front cover, and an air seal ring is installed at the front end of the front cover; the spindle is arranged in the housing through a front support bearing seat and a rear support bearing seat, the spindle is a hollow structure, a pull rod is passed through the hollow structure of the spindle, the pull rod is a multi-section structure, and the multiple sections are connected by threads, a pull claw is connected to the front end of the pull rod, a disc spring is passed through the pull rod, one end of the disc spring is pressed against the spindle, and a sealing locating sleeve is screwed on the other end of the disc spring, a rotary joint is connected to the rear end of the pull rod behind the sealing locating sleeve, a cooling water channel is provided in the center of the pull rod, and the cooling water channel is connected to the water path of the rotary joint, the center of the cylinder rod of the knife-beating cylinder is a cavity, a pull rod rear support bearing is provided in the cavity, the pull rod passes through the pull rod rear support bearing, and the knife-beating cylinder is fixedly connected to the rear end of the housing, characterized in that: The stator has a plastic sealing structure. The air sealing ring is composed of an outer ring and an inner ring fixed with the outer ring. An axial gas channel and radial air holes are provided on the outer ring. The radial air holes are connected to the axial gas channel. An annular groove 1 is provided on the outer circumferential surface of the inner ring. The annular groove 1 corresponds to the position of the radial air holes. The radial air holes are radially located outside the annular groove 1. A plurality of radial air distribution holes are provided on the bottom surface of the annular groove 1. The front support bearing seat and the rear support bearing seat are interference fit with the inner cavity of the shell, and the interference amount is 0.005-0.01mm; the pull rod rear support bearing is interference fit with the cavity, and the interference amount is 0.006-0.008mm; the disc spring is installed in the middle There are two sealing gaskets; grooves are provided on the outer periphery of the pulling claw, the sealing positioning sleeve and the outer periphery of the sealing gasket. There are two grooves on the outer periphery of the pulling claw and the sealing positioning sleeve, and sealing rings are sleeved in the grooves. There is an interference fit between the sealing ring and the cavity at this location, and the interference amount is 0.5mm. A support sleeve is fixedly connected to the rear end of the knife cylinder, and a mounting circular hole is provided on the rear end surface of the support sleeve. The diameter of the mounting circular hole is larger than the diameter of the rotary joint. Two sealing ring grooves are provided in the hole, and rotary joint sealing rings are installed in the two sealing ring grooves. There is an interference fit between the rotary joint and the rotary joint sealing ring; the interference amount between the rotary joint and the sealing ring is 0.25mm to 0.35mm.

2. The automatic tool-changing high-speed electric spindle with water passing through the middle hole according to claim 1 is characterized in that: A second annular groove is provided at the radial air hole on the outer ring, and the position of the second annular groove corresponds to that of the first annular groove.

3. The automatic tool-changing high-speed electric spindle with middle-hole water flow according to claim 1 is characterized in that: The number of the air distribution holes is 4-12.

4. The automatic tool-changing high-speed electric spindle with water passing through the middle hole according to claim 1 is characterized in that: The number of the air distribution holes is 8.

5. The automatic tool-changing high-speed electric spindle with water passing through the middle hole according to claim 1 is characterized in that: An annular groove three is provided on the inner circumferential surface of the inner ring, and the ends of each air distribution through hole are located in the annular groove three.

6. The automatic tool-changing high-speed electric spindle with water passing through the middle hole according to claim 1 is characterized in that: The single-side gap between the main shaft and the air sealing ring is 0.02 mm.

7. The automatic tool-changing high-speed electric spindle with water passing through the middle hole according to claim 1 is characterized in that: The interference between the rotary joint and the sealing ring is 0.3 mm.

8. The automatic tool-changing high-speed electric spindle with water passing through the middle hole according to claim 1 is characterized in that: The water outlet of the rotary joint is located outside the supporting sleeve.

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