Motor rear-mounted direct drive spindle

Abstract

The application discloses a motor rear-mounted direct-drive spindle, which comprises a spindle box body, a mandrel rotatably arranged in the spindle box body, a bearing and a torque motor, the bearing comprises a first bearing and a second bearing for realizing radial and axial support of the mandrel, and the first bearing and the second bearing are arranged in the interior of the spindle box body; one end of the mandrel extends to the exterior of the spindle box body, the torque motor and the spindle box body are arranged in the axial direction, the torque motor comprises a rotor and a stator, the end portion of the mandrel located at the exterior of the spindle box body is inserted into the end portion of the rotor, and the rotor and the mandrel are fixedly connected.The motor rear-mounted direct-drive spindle disclosed by the application adopts the mode that the motor is rear-mounted and the spindle motor is completely exposed, so that the motor is far away from the mandrel, the heat dissipation is improved, and the thermal elongation of the spindle is reduced.

Description

Technical Field

[0001] This invention relates to the field of machine tool technology, and in particular to a rear-mounted direct-drive spindle. Background Technology

[0002] An electric spindle is an electromechanical integrated functional component that houses a spindle motor to achieve power conversion and output. It is characterized by its compact structure and suitability for high-speed cutting.

[0003] Currently, the internal motor of the electric spindle is placed between two sets of support bearing components. During high-speed operation, the heat generated by the stator and rotor of the internal motor has a significant impact on the thermal performance of the electric spindle bearings and output end, which deteriorates the working conditions of the output end bearings, resulting in poor heat dissipation of the spindle and thermal expansion of the spindle.

[0004] Therefore, there is an urgent need to propose a motor spindle structure that can solve the problems of poor heat dissipation of the spindle and thermal expansion of the spindle when the motor with a central arrangement structure is running at high speed, from the perspective of mechanical structure and spindle balance. Summary of the Invention

[0005] This invention discloses a rear-mounted direct-drive spindle with the motor fully exposed, which keeps the motor away from the spindle, improves heat dissipation, and reduces the thermal elongation of the spindle.

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

[0007] A rear-mounted direct-drive spindle includes a spindle housing, a spindle rotatably disposed inside the spindle housing, bearings, and a torque motor. The bearings include a first bearing and a second bearing for radial and axial support of the spindle, both of which are disposed inside the spindle housing. One end of the spindle extends to the outside of the spindle housing. The torque motor and the spindle housing are arranged axially. The torque motor includes a rotor and a stator. The end of the spindle located outside the spindle housing is inserted into the end of the rotor, and the rotor and the spindle are fixedly connected.

[0008] Furthermore, the rotor is provided with a connecting disc along its radial direction, and the connecting disc is provided with connecting bolts. When the end face of the spindle contacts the connecting disc, the connecting bolts connect the spindle and the connecting disc.

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

[0010] Furthermore, the labyrinth structure is arranged on the side of the heat insulation ring facing the torque motor.

[0011] Furthermore, a brake disc and multiple clamps are provided at the end of the rotor away from the spindle, and the multiple clamps are arranged symmetrically at multiple points along the circumferential direction of the brake disc.

[0012] Furthermore, the brake disc is made of special steel and has a thickness of 1mm, forming a brake disc structure with a certain deformation capability.

[0013] Furthermore, a dynamic balancing probe is provided at the end of the spindle housing away from the torque motor. The dynamic balancing probe can detect the imbalance of the spindle after the workpiece is installed. An adjustment mechanism is provided at the end of the spindle to adjust the dynamic balance according to the measurement structure of the dynamic balancing probe.

[0014] Furthermore, the adjustment mechanism includes a balance disc and multiple balance adjustment blocks, the multiple balance adjustment blocks being slidably connected to the balance disc, and a set screw being provided between the balance adjustment blocks and the balance disc, the set screw being threadedly connected to the balance adjustment blocks;

[0015] The balance disc is provided with a scale, and the balance adjustment block is provided with an indicator arrow.

[0016] Furthermore, the balance disc has an annular sliding groove, and the inner diameter of the sliding groove gradually increases from the opening end of the sliding groove to the bottom wall of the sliding groove. The balance adjustment block is set in a trapezoidal shape.

[0017] Furthermore, the spindle housing is provided with a cooling water channel for cooling the first bearing.

[0018] The beneficial effects of the rear-mounted direct-drive spindle disclosed in this invention are as follows:

[0019] 1. The motor is rear-mounted, so that the torque motor is completely exposed outside the spindle housing. Since the spindle needs to run in for normal operation, when the spindle temperature rise is constant, the heat generated is equal to the heat dissipation. The heat of the first bearing and the second bearing in the rear-mounted motor structure is kept constant through the heat dissipation of the spindle housing. The temperature is constant and the temperature rise is low, thus achieving small thermal expansion of the spindle.

[0020] 2. Due to the advantages of torque motors, such as small axial dimensions, low inertia, light weight, rapid response, and low noise and vibration transmission, the overall structure of the motor after it is placed externally is not much different from the overall structure of the motor when it is placed in the middle. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1This is a schematic diagram of the overall structure of the rear-mounted direct-drive spindle of the motor disclosed in this invention.

[0023] Figure 2 This is a partial exploded view of the rear-mounted direct-drive spindle of the motor disclosed in this invention;

[0024] Figure 3 for Figure 1 Top view;

[0025] Figure 4 for Figure 3 A sectional view along line AA in the middle;

[0026] Figure 5 This is a top view of the rear-mounted direct-drive spindle of the motor disclosed in this invention;

[0027] Figure 6 for Figure 5 A sectional view along the BB direction in the middle;

[0028] Figure 7 for Figure 6 Enlarged view of section C in the image;

[0029] Figure 8 for Figure 6 Enlarged view of part D in the image.

[0030] In the diagram: 1. Torque motor; 11. Rotor; 111. Mounting flange; 112. Encoder flange; 12. Stator; 13. Housing; 2. Spindle housing; 3. Mandrel; 41. First bearing; 42. Second bearing; 51. Inner spacer; 52. Outer spacer; 6. Cooling water channel; 61. Inlet channel; 62. Outlet channel; 71. Connecting disc; 72. Connecting bolt; 81. Brake disc; 82. Clamp; 9. Cooling water system; 91. Water-cooled connector; 10. Heat insulation ring; 101. Labyrinth structure; 20. Dynamic balancing probe; 30. Adjustment mechanism; 301. Balance disc; 3011. Sliding groove; 3012. Scale; 302. Balance adjustment block; 303. Set screw. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the appendices in the embodiments of the present invention. Figure 1-8 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] A rear-mounted direct-drive spindle, mounted on a CNC machine tool, is described in reference to... Figure 1The assembly includes a torque motor 1 and a spindle housing 2 arranged axially side by side. The spindle housing 2 has a mounting cavity on the side facing the torque motor 1. The end of the torque motor 1 is inserted into the interior of the spindle housing 2, and the torque motor 1 and the spindle housing 2 are connected together by screws to form a rear-mounted main motor structure. This reduces the thermal influence between the motor and the bearing, and allows the torque motor 1 to be completely exposed outside the spindle housing 2, ensuring the heat dissipation of the torque motor 1. At the same time, the torque motor 1 has the advantages of small axial dimension, low inertia, light weight, fast response, and low noise and vibration transmission, which can ensure that the overall size after assembly is small.

[0033] Combination Figure 1 and Figure 2 The spindle housing 2 is a fully enclosed cylinder. A through hole is opened in the spindle housing 2 along its axis. A spindle 3 is installed in the through hole of the spindle housing 2. The end of the spindle 3 near the torque motor 1 extends to the outside of the spindle housing 2 and is connected to the torque motor 1, so that the spindle 3 can be driven to rotate when the torque motor 1 is started.

[0034] Combination Figure 1 and Figure 2 The spindle housing 2 houses bearings, including a first bearing 41 and a second bearing 42 that provide radial and axial support for the spindle 3. The first bearing 41 is installed at the end of the spindle 3 furthest from the torque motor 1, and the second bearing 42 is located at the end closest to the torque motor 1. The rotation between the spindle 3 and the spindle housing 2 is achieved through the cooperation of the first bearing 41 and the second bearing 42. Inner spacers 51 and outer spacers 52 are respectively provided on both sides of the axial direction of the first bearing 41 and the second bearing 42. The inner spacers 51 of the first bearing 41 and the inner spacers 51 of the second bearing 42 are integral structures, and the position of the bearings is restricted by the action of the inner spacers 51 and the outer spacers 52.

[0035] Combination Figure 3 and Figure 4 The spindle housing 2 is provided with cooling water channels 6 for cooling the second bearing 42. The cooling water channels 6 are arranged in a ring and are fitted around the second bearing 42. The cooling water channels 6 include an inlet channel 61 and an outlet channel 62. The inlet channel 61 and the outlet channel 62 are located on the upper and lower sides of the spindle housing 2, respectively. The inlet channel 61 is located below the spindle housing 2, and the outlet channel 62 is located above the spindle housing 2. Both the inlet channel 61 and the outlet channel 62 are inclined, which can achieve cooling of the second bearing 42 and thus reduce the thermal elongation of the spindle 3.

[0036] Combination Figure 5 and Figure 6 The torque motor 1 includes a rotor 11, a stator 12, and a housing 13, with the stator 12 and the housing 13 fixedly connected.

[0037] Combination Figure 6 and Figure 7 The rotor 11 has an axial insertion cavity, and the end of the spindle 3 is inserted into the cavity. An annular connecting disc 71 extends radially inward from the rotor 11, with its end face flush with the end face of the spindle 3. Multiple connecting bolts 72 are provided on the connecting disc 71, evenly spaced along its circumferential direction. During installation, the end of the spindle 3, located outside the spindle housing 2, is inserted into the rotor 11. The connecting disc 71 and the connecting bolts 72 securely connect the spindle 3 and the rotor 11, enabling rotational drive of the spindle 3. Simultaneously, since both the spindle 3 and the torque motor 1 rotor 11 require a running-in period during rotation, the temperature rise of the rotor 11 and the spindle 3 remains constant, with heat generation equal to heat dissipation. By placing the torque motor 1 at the rear, its heat is easily dissipated, resulting in a constant temperature, low temperature rise, and minimal thermal expansion of the spindle 3.

[0038] Combination Figure 2 and Figure 6 A brake disc 81 is fixedly mounted on the side of the torque motor 1 away from the main shaft housing 2. The brake disc 81 is a ring-shaped structure made of special steel, and the thickness of the brake disc 81 is preferably 1mm, forming a brake disc 81 structure with a certain deformation capability, making the brake disc 81 an elastic body. A mounting flange 111 and an encoder are fixedly mounted on the end of the rotor 11 away from the spindle 3. The encoder is fixed to the end of the rotor 11 through the encoder flange 112. The brake disc 81 and the mounting flange 111 are connected together by screws, so that the brake disc 81 and the rotor 11 are rigidly connected as a whole.

[0039] Combination Figure 2 and Figure 6 The brake disc 81 is provided with multiple clamps 82 in the circumferential direction, and the multiple clamps 82 are arranged symmetrically at multiple points along the circumferential direction of the brake disc 81. Each pair of clamps 82 forms a group, and multiple groups of clamps 82 are arranged in the circumferential direction of the brake disc 81. In this embodiment, taking a group of clamps 82 as an example, the two clamps 82 in the same group are symmetrically arranged with the center of the brake disc 81 as the center. The clamp 82 is preferably a high-precision clamp 82, and more preferably a hydraulic clamp 82. When the brake disc 81 receives a locking command, hydraulic oil enters the locking clamp 82. The clamp 82 is pushed by the hydraulic oil, causing it to squeeze the brake disc 81. The friction between the brake disc 81 and the clamp 82 generates a locking torque. During the locking process, the clamp 82 pushes the brake disc 81 forward slightly, causing the brake disc 81 and the rotor 11 to come into contact. The brake disc 81 is an elastic body. At this time, the brake disc 81 deforms, but the rotor 11 does not undergo radial deformation, thus preventing the spindle 3 from undergoing radial deformation. If the brake disc 81 is rigid enough, the braking force will cause the rotor 11 and the spindle 3 to undergo radial deformation, putting a load on the bearing and seriously affecting the bearing life.

[0040] Combination Figure 2 and Figure 6 The torque motor 1 is also equipped with a cooling water system 9 for cooling the stator 12. The cooling water system 9 includes a water-cooling connector 91 and a water-cooling pipe. Coolant is introduced into the water-cooling pipe through the water-cooling connector 91 to cool the stator 12.

[0041] Combination Figure 6 and Figure 7 A ring-shaped heat insulation ring 10 is provided between the torque motor 1 and the spindle housing 2, and the heat insulation ring 10 and the spindle housing 2 are connected together by screws. A labyrinth structure 101 is provided on the side of the heat insulation ring 10 facing the torque motor 1. The labyrinth structure 101 is composed of multiple spirally arranged annular grooves. The multiple annular grooves are concentrically arranged, which makes 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.

[0042] Currently, only the spindle 3 system undergoes dynamic balancing testing and adjustment. When users process workpieces with uneven weight, vibrations occur during machining, making it difficult to increase the spindle 3's rotational speed and causing significant damage to the spindle 3 bearings. To address this issue, a solution is needed, combining... Figure 6 and Figure 8 A dynamic balancing probe 20 and an adjustment mechanism 30 are arranged on the side of the spindle housing 2 away from the torque motor 1. The dynamic balancing probe 20 is preferably a high-precision dynamic balancing tester for machine tools. The dynamic balancing probe 20 has functions such as harmonic vibration analysis and can analyze the unbalanced vibration of the spindle 3 in real time. It can detect the unbalance of the spindle 3 after the workpiece is installed.

[0043] Combination Figure 6 and Figure 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 according to the measurement results of the dynamic balance probe 20. The balance disc 301 is arranged in an annular shape and is parallel to the brake disc 81. The balance disc 301 and the spindle 3 are connected together by screws.

[0044] Combination Figure 6 and Figure 8 The balance disc 301 has an annular sliding groove 3011 on the side facing away from the spindle housing 2. The sliding groove 3011 is located at the edge of the balance disc 301. From the opening end of the sliding groove 3011 to the bottom wall of the sliding groove 3011, the inner diameter of the sliding groove 3011 gradually increases. At this time, the axial section of the sliding groove 3011 is trapezoidal. There are multiple balance adjustment blocks 302. The multiple balance adjustment blocks 302 are equally spaced along the circumference of the balance disc 301, so as to balance the eccentricity of different workpieces.

[0045] Combination Figure 6 and Figure 8 The balance adjustment block 302 is trapezoidal in shape and is embedded inside the sliding groove 3011, so that the balance adjustment block 302 and the sliding groove 3011 fit together in a dovetail shape. The balance adjustment block 302 and the balance disk 301 are slidably connected. By adjusting the position of different balance adjustment blocks 302 on the balance disk 301, the center of gravity of the balance disk 301 can be adjusted.

[0046] Combination Figure 6 and Figure 8 The balance adjustment block 302 has a threaded hole, through which a set screw 303 passes. The set screw 303 and the balance adjustment block 302 are threaded together. The end of the set screw 303 passes through the balance adjustment block 302 and contacts the bottom wall of the sliding groove 3011. By locking the balance adjustment block 302 with the set screw 303, the center of gravity of the balance disc 301 can be adjusted.

[0047] Combination Figure 6 and Figure 8 The balance disc 301 has a scale 3012 on its edge, and the balance adjustment block 302 has an arrow pointing to the scale 3012, with the arrow located at the center of the balance adjustment block 302. When connecting a workpiece, the workpiece weight eccentricity causes the spindle 3 to vibrate, making it difficult for the spindle 3 to reach high speeds. The vibration causes significant damage to the bearings of the spindle 3. By adding a dynamic balancing probe 20 and an adjustment mechanism 30, the dynamic balance of the spindle system can be adjusted according to the increment of the detection data. The balance adjustment block 302 is locked with a set screw 303, making installation convenient. The higher the spindle 3 speed, the tighter the balance adjustment block 302 is under the force.

[0048] The implementation principle of this application is as follows: By adopting a rear-mounted motor, the torque motor 1 is fully exposed outside the spindle housing 2, forming a rear-mounted main motor structure, which reduces the thermal influence between the motor and the bearing; the end of the spindle 3 closest to the torque motor 1 is extended to the outside of the spindle housing 2 and connected to the torque motor 1. While driving the rotation of the spindle 3, the torque motor 1 and the spindle 3 are moved away from each other. Since the spindle 3 and the rotor 11 of the torque motor 1 need to run-in during rotation, the temperature rise of the rotor 11 and the spindle 3 is constant, and the heat generated is equal to the heat dissipation. By placing the torque motor 1 at the rear, the heat of the torque motor 1 is easily dissipated, the temperature is constant, and the temperature rise is low, resulting in small thermal elongation of the spindle 3. This fundamentally changes the structural characteristics of the electric spindle, so that when the electric spindle is running normally, the heat dissipated by the torque motor 1 has little thermal influence on the output end of the spindle 3.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rear-mounted direct-drive spindle, characterized in that, The device includes a spindle housing (2), a spindle (3) rotatably disposed inside the spindle housing (2), bearings, and a torque motor (1). The bearings include a first bearing (41) and a second bearing (42) that provide radial and axial support for the spindle (3). Both the first bearing (41) and the second bearing (42) are disposed inside the spindle housing (2). One end of the spindle (3) extends to the outside of the spindle housing (2). The torque motor (1) and the spindle housing (2) are arranged axially. The torque motor (1) includes a rotor (11) and a stator (12). The end of the spindle (3) located outside the spindle housing (2) and the end of the rotor (11) are inserted into each other. The rotor (11) and the spindle (3) are fixedly connected. A heat insulation ring (10) is also provided between the stator (12) and the spindle housing (2) of the torque motor (1). The heat insulation ring (10) is provided with a labyrinth structure (101) on the side facing the torque motor (1). The labyrinth structure (101) is composed of multiple concentric annular grooves.

2. The rear-mounted direct-drive spindle according to claim 1, characterized in that, The rotor (11) is provided with a connecting disc (71) in its radial direction. The connecting disc (71) is provided with a connecting bolt (72). When the end face of the spindle (3) contacts the connecting disc (71), the connecting bolt (72) connects the spindle (3) and the connecting disc (71).

3. The rear-mounted direct-drive spindle according to claim 1, characterized in that, The rotor (11) is also provided with a brake disc (81) and multiple clamps (82) at the end away from the spindle (3), and the multiple clamps (82) are arranged symmetrically at multiple points along the circumferential direction of the brake disc (81).

4. A rear-mounted direct-drive spindle according to claim 3, characterized in that, The brake disc (81) is made of special steel and has a thickness of 1 mm, forming a brake disc (81) structure with a certain deformation capability.

5. A rear-mounted direct-drive spindle according to claim 1, characterized in that, A dynamic balancing probe (20) is provided at the end of the spindle housing (2) away from the torque motor (1). The dynamic balancing probe (20) can detect the imbalance of the spindle (3) after the workpiece is installed. An adjustment mechanism (30) is provided at the end of the spindle (3) to adjust the dynamic balance according to the structure measured by the dynamic balancing probe (20).

6. A rear-mounted direct-drive spindle according to claim 5, characterized in that, The adjustment mechanism (30) includes a balance disc (301) and a plurality of balance adjustment blocks (302). The plurality of balance adjustment blocks (302) are slidably connected to the balance disc (301). A set screw (303) is provided between the balance adjustment block (302) and the balance disc (301). The set screw (303) is threadedly connected to the balance adjustment block (302). The balance disc (301) is provided with a scale (3012), and the balance adjustment block (302) is provided with an indicator arrow.

7. A rear-mounted direct-drive spindle according to claim 6, characterized in that, The balance disc (301) has an annular sliding groove (3011) with the inner diameter of the sliding groove (3011) gradually increasing from the opening end to the bottom wall of the sliding groove (3011). The balance adjustment block (302) is set in a trapezoidal shape.

8. A rear-mounted direct-drive spindle according to claim 1, characterized in that, The spindle housing (2) is provided with a cooling water channel (6) that can cool the first bearing (41).

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