Rear motor direct drive spindle

Abstract

The present invention discloses a rear motor direct drive spindle including a spindle housing, a mandrel rotatably installed inside the spindle housing, a bearing, and a torque motor, the bearing includes a first bearing and a second bearing for supporting the mandrel in the radial and axial directions, the first bearing and the second bearing are both installed inside the spindle housing, one end of the mandrel extends to the outside of the spindle housing, the torque motor and the spindle housing are arranged along the axial direction, the torque motor includes a rotor and a stator, an end of the mandrel located outside the spindle housing and an end of the rotor are inserted, and the rotor and the mandrel are fixedly connected. The rear motor direct drive spindle disclosed in the present invention uses a rear motor spindle to expose the entire motor to the outside, and separates the motor from the mandrel, improving heat dissipation and reducing the thermal expansion of the spindle.

Description

[Technical Field]

[0001] The present invention relates to the field of machine tool technology, and more particularly to a rear motor direct drive spindle. [Background technology]

[0002] An electric spindle is a functional component that incorporates a spindle motor and integrates electromechanical functions to convert power and achieve output. Its notable features are its compact structure and its use in high-speed cutting.

[0003] The built-in motor of current electric spindles is located between two sets of support bearing members, and the heat generated by the stator and rotor of the built-in motor during high-speed operation has a large thermal impact on the bearings and output end of the electric spindle, worsening the operating conditions of the output end bearing, resulting in poor heat dissipation from the mandrel and large thermal expansion of the spindle.

[0004] Therefore, from the viewpoint of the balance between the mechanical structure and the spindle, it is urgent to provide a motor spindle structure that solves the problem of poor heat dissipation from the mandrel and large thermal expansion of the spindle when a motor with a structure that is placed in the middle of the motor rotates at high speed. Summary of the Invention

[0005] The present invention discloses a rear motor direct drive spindle, which uses a rear motor spindle to expose the entire motor to the outside and separate the motor from the mandrel, thereby improving heat dissipation and reducing the thermal expansion of the spindle.

[0006] To achieve the above objectives, the technical solutions of the present invention are as follows:

[0007] The rear motor direct drive spindle includes a spindle housing, a mandrel rotatably installed inside the spindle housing, a bearing, and a torque motor, the bearing includes a first bearing and a second bearing that support the mandrel in the radial and axial directions, both the first bearing and the second bearing are installed inside the spindle housing, one end of the mandrel extends outside the spindle housing, the torque motor and spindle housing are arranged along the axial direction, the torque motor includes a rotor and a stator, the end of the mandrel located outside the spindle housing and the end of the rotor are inserted and the rotor and mandrel are fixedly connected.

[0008] Furthermore, a connecting disk is installed along the radial direction of the rotor, and a connecting bolt is installed on the connecting disk, and when the end face of the mandrel and the connecting disk come into contact with each other, the connecting bolt connects the mandrel and the connecting disk.

[0009] Furthermore, a heat insulating ring or labyrinth structure is further installed between the torque motor and the spindle housing.

[0010] Furthermore, the labyrinth structure is disposed on the side of the insulating ring facing the torque motor.

[0011] Furthermore, a brake disc and a plurality of clamps are further provided at one end of the rotor away from the mandrel, and the clamps are arranged symmetrically with respect to a plurality of points along the circumferential direction of the brake disc.

[0012] Furthermore, the brake disc is manufactured using a special steel material, and the thickness of the brake disc is 1 mm, forming a brake disc structure with a certain deformation capacity.

[0013] Furthermore, a dynamic balance measuring head is installed at one end of the spindle housing away from the torque motor, and the dynamic balance measuring head can detect the amount of imbalance of the mandrel after a workpiece is attached, and an adjustment mechanism is installed at the end of the mandrel, which can adjust the dynamic balance based on the measurement results of the dynamic balance measuring head.

[0014] Furthermore, the adjustment mechanism includes a balance disk and a plurality of balance adjustment blocks, each of the plurality of balance adjustment blocks is slidably connected to the balance disk, a cap bolt is installed between the balance adjustment block and the balance disk, and the cap bolt and the balance adjustment block are connected by a screw; The balance disc is provided with a scale, and the balance adjustment block is provided with an indicating arrow.

[0015] Furthermore, an annular slide groove is formed in the balance disc, and the inner diameter of the slide groove gradually increases from the open end to the bottom wall of the slide groove, and the balance adjustment block is disposed in a trapezoidal shape.

[0016] Furthermore, a cooling water flow path capable of cooling the first bearing is installed in the spindle housing.

[0017] The beneficial effects of the rear motor direct drive spindle disclosed in the present invention are as follows:

[0018] 1. A rear motor is used, and the torque motor is entirely exposed to the outside of the spindle housing. A break-in is required for the mandrel to operate normally. When the temperature rise of the mandrel is constant, the amount of heat generated is equal to the amount of heat dissipated. Therefore, the heat amount of the first bearing and the second bearing in the rear motor structure becomes constant due to the heat dissipation from the spindle housing. When the temperature is constant, the temperature rise is small, and therefore the thermal expansion of the spindle is small.

[0019] 2. Torque motors have the advantages of small axial dimensions, low inertia, light weight, fast response, and low noise and vibration transmission, so there is little difference in dimensions between the overall structure with the motor externally mounted and the overall structure with the motor positioned intermediately.

[0020] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces drawings necessary for describing the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative efforts. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of the overall structure of a rear motor direct drive spindle disclosed in the present invention. [Figure 2] FIG. 1 is a partial exploded view of a rear motor direct drive spindle disclosed in the present invention. [Figure 3] FIG. 2 is a plan view of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 1 is a plan view of a rear motor direct drive spindle disclosed in the present invention. [Figure 6] FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5. [Figure 7] FIG. 7 is an enlarged view of part C in FIG. [Figure 8] FIG. 7 is an enlarged view of part D in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0022] In order to clarify the objectives, technical solutions and advantages of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to Figures 1 to 8 in the embodiments of the present invention. It should be obvious that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without any creative efforts fall within the protection scope of the present invention.

[0023] The rear motor direct drive spindle is mounted on a numerically controlled machine tool. Referring to FIG. 1, it comprises a torque motor 1 and a spindle housing 2 arranged in parallel in the axial direction. A mounting cavity is opened on the side of the spindle housing 2 facing the torque motor 1. The end of the torque motor 1 is inserted into the spindle housing 2, and the torque motor 1 and the spindle housing 2 are connected together with screws to form a rear main motor type structure, which reduces the thermal influence between the motor and the bearing. Furthermore, the torque motor 1 is entirely exposed to the outside of the spindle housing 2, which ensures the torque motor 1's heat dissipation. At the same time, the torque motor 1 has the advantages of a small axial dimension, small inertia, light weight, fast response, and low noise and vibration transmission, and can ensure a small overall volume after assembly.

[0024] 1 and 2, the spindle housing 2 is a completely sealed cylindrical body, and a circular through-hole is formed in the spindle housing 2 along its axial direction. A mandrel 3 is attached to the circular through-hole of the spindle housing 2. One end of the mandrel 3, which is close to the torque motor 1, extends outside the spindle housing 2 and is integrally connected to the torque motor 1. When the torque motor 1 is started, the mandrel 3 can be driven to rotate.

[0025] 1 and 2, bearings are mounted inside the spindle housing 2, and the bearings include a first bearing 41 and a second bearing 42 that provide radial and axial support for the mandrel 3. The first bearing 41 is mounted at one end of the mandrel 3 away from the torque motor 1, and the second bearing 42 is disposed at one end close to the torque motor 1. By fitting the first bearing 41 and the second bearing 42 together, rotation between the mandrel 3 and the spindle housing 2 is achieved. An inner spacer 51 and an outer spacer 52 are respectively mounted on both axial sides of the first bearing 41 and the second bearing 42. The inner spacer 51 of the first bearing 41 and the outer spacer 52 of the second bearing 42 are of an integral structure, and the inner spacer 51 and the outer spacer 52 act to limit the position of the bearings.

[0026] 3 and 4, a cooling water passage 6 capable of cooling the second bearing 42 is arranged in the spindle housing 2. The cooling water passage 6 is arranged in a ring shape and is fitted around the second bearing 42. The cooling water passage 6 includes a water supply passage 61 and a water drain passage 62. The water supply passage 61 and the water drain passage 62 are respectively located on the upper and lower sides of the spindle housing 2. The water supply passage 61 is located below the spindle housing 2, and the water drain passage 62 is located above the spindle housing 2. The water supply passage 61 and the water drain passage 62 are both installed at an angle, which can cool and reduce the temperature of the second bearing 42 and reduce the thermal expansion of the mandrel 3.

[0027] 5 and 6, the torque motor 1 includes a rotor 11, a stator 12, and a housing 13, with the stator 12 fixedly connected to the housing 13.

[0028] 6 and 7, an insertion cavity is formed in the axial direction of the rotor 11, and the end of the mandrel 3 is inserted into the insertion cavity. The rotor 11 has an annular connecting disk 71 extending radially inward, with the end face of the connecting disk 71 flush with the end face of the mandrel 3. A plurality of connecting bolts 72 are installed on the connecting disk 71, and the plurality of connecting bolts 72 are arranged at equal intervals along the circumferential direction of the connecting disk 71. During installation, the end of the mandrel 3 located outside the spindle housing 2 is inserted into the rotor 11, and the connecting disk 71 and the connecting bolts 72 act to fix and connect the mandrel 3 and the rotor 11 together, thereby realizing the rotational drive of the mandrel 3. At the same time, both the mandrel 3 and the rotor 11 of the torque motor 1 require break-in during the rotation process, which ensures a constant temperature rise in the rotor 11 and the mandrel 3. The amount of heat generated is equal to the amount of heat dissipated. Therefore, by placing the torque motor 1 at the rear, the heat of the torque motor 1 can be easily dissipated, the temperature is constant, the temperature rise is small, and the thermal expansion of the mandrel 3 is small.

[0029] 2 and 6, a brake disc 81 is fixedly provided on the side of the torque motor 1 away from the spindle housing 2. The brake disc 81 is an annular disc structure made of a special steel material, and the thickness of the brake disc 81 is preferably 1 mm, which provides the brake disc 81 with a certain degree of deformation capacity, thereby making the brake disc 81 an elastic body. A mounting flange 111 and an encoder are fixedly attached to one end of the rotor 11 away from the mandrel 3. The encoder is fixedly attached to the end of the rotor 11 via an encoder flange 112. The brake disc 81 and the mounting flange 111 are connected together with screws, rigidly connecting the brake disc 81 and the rotor 11 together.

[0030] 2 and 6, a plurality of clamps 82 are provided in the circumferential direction of the brake disc 81, and the plurality of clamps 82 are arranged symmetrically at a plurality of points along the circumferential direction of the brake disc 81. Two clamps 82 form a set, and a plurality of sets of clamps 82 are arranged in the circumferential direction of the brake disc 81. In this embodiment, one set of clamps 82 is used as an example, and the two clamps 82 in the same set are arranged symmetrically with respect to the center of the brake disc 81. The clamp 82 is preferably a high-precision clamp 82, and more preferably a hydraulic clamp 82. When the brake disc 81 receives a lock command, hydraulic oil enters the lock clamp 82, and the clamp 82 is subjected to the thrust of the hydraulic oil, causing the clamp 82 to press against the brake disc 81. The frictional force between the brake disc 81 and the clamp 82 generates a lock torque. During the locking process, the clamp 82 pushes the brake disc 81 forward, causing the brake disc 81 to move slightly and fit tightly against the rotor 11. Because the brake disc 81 is an elastic body, the brake disc 81 deforms at this time, but no radial deformation occurs in the rotor 11, and therefore no radial deformation occurs in the mandrel 3. If the rigidity of the brake disc 81 is high, the braking force will move the rotor 11 and mandrel 3 and cause radial deformation, which will put a load on the bearing and seriously affect the service life of the bearing.

[0031] 2 and 6, the torque motor 1 is further provided with a cooling water system 9 capable of cooling the stator 12. The cooling water system 9 includes a water cooling joint 91 and a water cooling pipe, and a cooling liquid is introduced into the water cooling pipe via the water cooling joint 91 to reduce the temperature of the stator 12.

[0032] 6 and 7, an annular heat insulating ring 10 is installed between the torque motor 1 and the spindle housing 2, and the heat insulating ring 10 and the spindle housing 2 are connected together with screws. A labyrinth structure 101 is arranged on the side of the heat insulating ring 10 facing the torque motor 1, and the labyrinth structure 101 is composed of a plurality of annular grooves arranged in a spiral, and the plurality of annular grooves are arranged concentrically, making it difficult for the heat generated by the torque motor 1 to be transferred to the spindle housing 2, further reducing the thermal influence between the motor and the bearing.

[0033] In conventional mandrels 3, dynamic balance detection and adjustment is performed only on the mandrel 3 axis system. If there is an imbalance when the user processes a workpiece blank, vibrations will occur when processing such a part, making it difficult to increase the rotation speed of the mandrel 3 and causing significant damage to the mandrel 3 bearings. To solve this problem, referring to Figures 6 and 8, a dynamic balance measuring head 20 and adjustment mechanism 30 are located on the side of the spindle housing 2 away from the torque motor 1. The dynamic balance measuring head 20 is preferably a high-precision dynamic balance detector for machine tools. The dynamic balance measuring head 20 has functions such as harmonic vibration analysis, and can analyze the unbalanced vibration of the mandrel 3 in real time, and can detect the amount of unbalance of the mandrel 3 after the workpiece is attached.

[0034] 6 and 8, the adjustment mechanism 30 includes a circular balance disc 301 and a balance adjustment block 302. The balance disc 301 can adjust the dynamic balance based on the measurement results of the dynamic balance measuring head 20. The balance disc 301 is installed as an annular disc, and the balance disc 301 and the brake disc 81 are parallel to each other. The balance disc 301 and the mandrel 3 are connected together by screws.

[0035] 6 and 8, an annular slide groove 3011 is formed on the side of the balance disk 301 opposite to the spindle housing 2. The slide groove 3011 is disposed on the edge of the balance disk 301. The inner diameter of the slide groove 3011 gradually increases from the open end to the bottom wall of the slide groove 3011. The axial cross section of the slide groove 3011 is trapezoidal. There are multiple balance adjustment blocks 302, which are arranged at equal intervals along the circumferential direction of the balance disk 301, so as to balance the eccentricities of different workpieces.

[0036] 6 and 8, the balance adjusting block 302 is trapezoidally installed, and is fitted into the slide groove 3011, with the balance adjusting block 302 and the slide groove 3011 being fitted together in a dovetail shape. The balance adjusting block 302 is slidably connected to the balance disk 301, and the position of the different balance adjusting blocks 302 on the balance disk 301 can be adjusted to achieve adjustment of the center of gravity of the balance disk 301.

[0037] 6 and 8, a threaded hole is drilled in the balance adjustment block 302, and a cap bolt 303 is drilled into the threaded hole. The cap bolt 303 is screwed into the balance adjustment block 302, and the end of the cap bolt 303 passes through the balance adjustment block 302 and contacts the bottom wall of the slide groove 3011. The cap bolt 303 locks the balance adjustment block 302, thereby enabling adjustment of the center of gravity of the balance disk 301.

[0038] 6 and 8, a scale 3012 is provided on the edge of the balance disc 301, and an arrow indicating the scale 3012 is provided on the balance adjustment block 302, with the arrow located at the center of the balance adjustment block 302. When a workpiece is connected, the vibration of the mandrel 3 due to the eccentricity of the workpiece's weight makes it difficult to increase the rotation speed of the mandrel 3, and the damage caused by the vibration to the bearings of the mandrel 3 increases. However, by adding the dynamic balance measuring head 20 and adjustment mechanism 30, the dynamic balance of the spindle shaft system can be adjusted based on the number of increments of detected data. The balance adjustment block 302 is locked with a cap bolt 303, making installation easy. The faster the rotation speed of the mandrel 3, the tighter the balance adjustment block 302 becomes due to the action of centrifugal force.

[0039] The implementation principle of this application is as follows: A rear motor is adopted, and the torque motor 1 is entirely exposed to the outside of the spindle housing 2, forming a rear main motor structure and reducing the thermal impact between the motor and the bearing. One end of the mandrel 3 adjacent to the torque motor 1 extends outside the spindle housing 2 and is integrally connected to the torque motor 1 to achieve rotational drive for the mandrel 3, while separating the torque motor 1 from the mandrel 3. During the rotation process of the mandrel 3 and the rotor 11 of the torque motor 1, both require break-in, which ensures a constant temperature rise for the rotor 11 and the mandrel 3, and the heat generated is equal to the heat dissipation. Therefore, by placing the torque motor 1 at the rear, the heat generated by the torque motor 1 can be easily dissipated, with a constant temperature, a small temperature rise, and small thermal expansion of the mandrel 3. This fundamentally changes the structural features of the electric spindle, ensuring normal operation of the electric spindle while minimizing the thermal impact of the heat emitted by the torque motor 1 on the output end of the mandrel 3.

[0040] Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention, and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified or some or all of the technical features therein may be equivalently replaced, and such modifications or replacements do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention. [Explanation of symbols]

[0041] 1 torque motor 11 Rotor 111 Mounting flange 112 Encoder flange 12 Stator 13. Housing 2 Spindle housing 3 mandrels 41 First bearing 42 Second bearing 51 Inner spacer 52 Outer spacer 6 Cooling water flow path 61 Water supply channel 62 Drainage channel 71 Connected Disk 72 Connection bolt 81 Brake disc 82 Clamp 9 Cooling water system 91 Water cooling joint 10 Insulation ring 101 Labyrinth Structure 20 Dynamic balance measurement head 30 Adjustment mechanism 301 Balance Disc 3011 Slide groove 3012 scale 302 Balancing Block 303 Cap bolt

Claims

1. The spindle includes a spindle housing (2), a mandrel (3) rotatably installed inside the spindle housing (2), a bearing, and a torque motor (1), The bearing includes a first bearing (41) and a second bearing (42) that realize radial and axial support for the mandrel (3), the first bearing (41) and the second bearing (42) are both installed inside the spindle housing (2), one end of the mandrel (3) extends outside the spindle housing (2), the torque motor (1) and the spindle housing (2) are arranged along the axial direction, the torque motor (1) includes a rotor (11) and a stator (12), an end of the mandrel (3) is located outside the spindle housing (2) and is inserted into an end of the rotor (11), and the rotor (11) and the mandrel (3) are fixedly connected; A rear motor direct drive spindle, characterized in that an insulating ring (10) or labyrinth structure (101) is further installed between the torque motor (1) and the spindle housing (2).

2. 2. The rear motor direct drive spindle according to claim 1, wherein a connecting disk (71) is installed along the radial direction of the rotor (11), a connecting bolt (72) is installed on the connecting disk (71), and when an end face of the mandrel (3) and the connecting disk (71) come into contact with each other, the connecting bolt (72) connects the mandrel (3) and the connecting disk (71).

3. 2. The rear motor direct drive spindle according to claim 1, wherein the labyrinth structure (101) is arranged on the side of the heat insulating ring (10) facing the torque motor (1).

4. 2. The rear motor direct drive spindle according to claim 1, further comprising a brake disc (81) and a plurality of clamps (82) disposed at one end of the rotor (11) away from the mandrel (3), the clamps (82) being disposed symmetrically with respect to a plurality of points along the circumferential direction of the brake disc (81).

5. 5. The rear motor direct drive spindle according to claim 4, wherein the brake disc (81) is manufactured using a special steel material, the thickness of the brake disc (81) is 1 mm, and the brake disc (81) structure has a certain deformation capacity.

6. 2. The rear motor direct drive spindle according to claim 1, wherein a dynamic balance measuring head (20) is installed at one end of the spindle housing (2) remote from the torque motor (1), the dynamic balance measuring head (20) is capable of detecting the amount of imbalance of the mandrel (3) after a workpiece is attached, and an adjustment mechanism (30) is installed at an end of the mandrel (3) to adjust the dynamic balance based on the measurement results of the dynamic balance measuring head (20).

7. The adjustment mechanism (30) includes a balance disc (301) and a plurality of balance adjustment blocks (302), each of which is slidably connected to the balance disc (301). A cap bolt (303) is installed between the balance adjustment block (302) and the balance disc (301), and the cap bolt (303) and the balance adjustment block (302) are screw-connected.

7. The rear motor direct drive spindle according to claim 6, wherein the balance disc (301) is provided with a scale (3012), and the balance adjustment block (302) is provided with an indicating arrow.

8. 8. The rear motor direct drive spindle of claim 7, wherein the balance disc (301) has an annular slide groove (3011), the inner diameter of the slide groove (3011) gradually increases from the open end of the slide groove (3011) to the bottom wall of the slide groove (3011), and the balance adjustment block (302) is installed in a trapezoidal shape.

9. 2. The rear motor direct drive spindle according to claim 1, wherein a cooling water flow path (6) capable of cooling the first bearing (41) is installed in the spindle housing (2).

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