Automatic balancer

Abstract

The present application provides an automatic balancer with a length in the axial direction of a rotating shaft that is shorter than conventional automatic balancers. The automatic balancer includes a balance head that rotates in unison with a rotating body about a rotating shaft of the rotating body, an electric balance correction mechanism that corrects an imbalance of the rotating body, and a housing that has a cylindrical outer peripheral surface parallel to the rotating shaft and houses the balance correction mechanism; a stator that is provided separately from the balance head, has a shape along the circumference of the outer peripheral surface with a gap from the outer peripheral surface, and is electrically connected to a controller of the balance head; and a rotor portion that is provided at a position on the outer peripheral surface opposite the stator, rotates in unison with the balance head, has a shape along the circumference of the outer peripheral surface, and is electrically connected to the balance correction mechanism, and wireless transmission is possible between the stator and the rotor.

Description

Technical Field

[0001] This invention relates to an automatic balancer for correcting imbalances in rotating bodies. Background Technology

[0002] Grinding apparatuses are known to perform grinding operations on workpieces using a disc-shaped grinding stone (rotating body) that rotates at high speed via a spindle. The grinding apparatus is equipped with an automatic balancer capable of automatically correcting imbalances in the high-speed rotating grinding stone (see Patent Document 1). The automatic balancer comprises: a balancing head connected to and rotating integrally with the grinding stone; and a stator (also called a sender) that transmits drive power and drive commands to the balancing head input from a controller. The balancing head corrects the imbalance of the grinding stone by moving multiple counterweights within it based on the drive power and drive commands input from the stator.

[0003] As such an automatic balancing device, an automatic balancing device having a non-contact balancing head and a stator is known (see Patent Document 2). The stator described in Patent Document 2 includes a transmitter capable of wirelessly transmitting drive power and drive commands, and a stator coil. This stator is arranged opposite to the front end face of the balancing head on the side opposite to the rear end face connected to the grinding stone. Furthermore, a rotor is provided on the front end face of the balancing head described in Patent Document 2. The rotor is provided with a rotor coil for receiving drive power and drive commands wirelessly transmitted from the stator, and a receiving circuit. Therefore, drive power and drive commands can be wirelessly transmitted from the stator to the balancing head without connecting the stator to the balancing head.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-232563

[0007] Patent Document 2: Japanese Patent Application Publication No. 2011-95163 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, existing automatic balancing devices with non-contact balancing heads and stators employ a structure in which the balancing head and stator are arranged in parallel along the axis of rotation that rotates the grinding wheel or other rotating body. That is, the balancing head and stator are arranged opposite each other in a parallel, overlapping manner in their respective thickness directions. As a result, the length (thickness) of the automatic balancing device along the axis of rotation increases, thus requiring sufficient space within the grinding apparatus for its installation. Furthermore, to accommodate the automatic balancing device within the grinding apparatus, the housing for housing the grinding wheel or other rotating body needs to be improved.

[0010] The present invention was made in view of the following circumstances, and its object is to provide an automatic balancer with a shorter axial length of the rotating shaft compared to the past.

[0011] Solution for solving the problem

[0012] For the automatic balancer used to achieve the present invention, the automatic balancer comprises: a balance head that rotates integrally with the rotating body about the rotation axis of the rotating body, having an electrically powered balance correction mechanism for correcting the imbalance of the rotating body, and a housing having a cylindrical outer peripheral surface parallel to the rotation axis and housing the balance correction mechanism; a stator that is separately disposed from the balance head, having a circumferential shape along the outer peripheral surface when separated from it by a gap, and being electrically connected to a controller of the balance head; and a rotor that is disposed on the outer peripheral surface opposite to the stator, rotates integrally with the balance head, has a circumferential shape along the outer peripheral surface, and is electrically connected to the balance correction mechanism, and is capable of wireless transmission between the stator and the rotor.

[0013] According to this automatic balancer, the stator clearance can be fitted into the outer peripheral surface of the balancing head housing, and the rotor section can be mounted on the outer peripheral surface of the housing.

[0014] In another embodiment of the invention, the stator is formed in a ring shape along the circumferential direction of its outer peripheral surface and is fitted with clearance within the outer peripheral surface. This allows for a reduction in the axial length of the automatic balancer along the rotating shaft.

[0015] In another embodiment of the present invention, the rotor section is formed in a ring shape along the circumferential direction of its outer peripheral surface. This enables wireless transmission between the stator and the rotor section.

[0016] In another embodiment of the present invention, the stator and rotor are positioned opposite each other along the axial direction of the rotation axis. This enables wireless transmission between the stator and rotor.

[0017] In another aspect of the automatic balancer, the stator wirelessly transmits the drive power and drive command of the balancing head output from the controller to the rotor. The rotor receives the drive power and drive command from the stator, and the balancing correction mechanism operates based on the drive power and drive command received by the rotor. Thus, drive power and drive command can be transmitted from the stator to the balancing head in a non-contact manner.

[0018] In another aspect of the automatic balancer, the automatic balancer includes a detection sensor disposed in the housing. This sensor detects contact between a contacted object and the rotating body. The rotor wirelessly transmits the detection signal from the sensor to the stator, and the stator inputs the detection signal received from the rotor to a controller. Thus, the detection signal can be transmitted from the balancing head to the stator in a non-contact manner.

[0019] Invention Effects

[0020] This invention can shorten the axial length of the automatic balancer on the rotating shaft. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating an example of applying an automatic balancing device to a grinding apparatus.

[0022] Figure 2 This is a 3D view of a non-contact balancing head and stator.

[0023] Figure 3 yes Figure 2 The exploded 3D view of the balance head and stator is shown.

[0024] Figure 4 yes Figure 2 The balancing head and stator are shown in a cross-sectional view along line 4-4.

[0025] Figure 5 This is an explanatory diagram used to illustrate the effect of the automatic balancer of this embodiment relative to the automatic balancer of the comparative example. Detailed Implementation

[0026] Figure 1 This is a schematic diagram illustrating an example of applying the automatic balancer 16 of the present invention to a grinding apparatus 10. It should be noted that only the main parts of the grinding apparatus 10 are shown.

[0027] like Figure 1 As shown, the grinding apparatus 10 is used, for example, in the grinding of the workpiece W, and includes a grinding stone 12, a spindle 14, and an automatic balancer 16.

[0028] The grinding stone 12 is equivalent to the rotating body of the present invention and is formed in the shape of a disc. The grinding stone 12 is rotatably held on the main shaft 14 about the rotation axis 14a. In addition, a balancing head 20 constituting an automatic balancing device 16 is connected to the grinding stone 12, and the grinding stone 12 and the balancing head 20 rotate together.

[0029] The spindle 14 has a built-in motor that rotates the grinding stone 12 at high speed around the rotating shaft 14a. It should be noted that the reference numeral Ax in the figure represents the axial direction of the rotating shaft 14a. Additionally, the reference numeral θ represents the direction of rotation of the rotating shaft 14a, i.e., the direction of rotation of the grinding stone 12 and the balancing head 20.

[0030] The automatic balancer 16 automatically corrects the imbalance of the high-speed rotating grinding stone 12. The automatic balancer 16 includes a non-contact balancing head 20 and stator 22, a vibration sensor 24, and a controller 26. It should be noted that, although the illustration is omitted, the automatic balancer 16 may also be equipped with a detection sensor to detect the rotation angle of the balancing head 20 (see Patent Document 2 above).

[0031] The balancing head 20 is connected to the grinding stone 12 via the adapter flange 28. Thus, as previously described, the grinding stone 12 and the balancing head 20 rotate integrally in the axial direction θ. The balancing head 20 operates based on drive power and drive commands input non-contactly from the controller 26 via the stator 22, correcting the imbalance of the high-speed rotating grinding stone 12.

[0032] Figure 2 This is a three-dimensional view of the non-contact balancing head 20 and the stator 22. Figure 3 yes Figure 2 An exploded perspective view of the balance head 20 and the stator 22 shown. Figure 4 yes Figure 2 The balancing head 20 and stator 22 are shown in a cross-sectional view along line 4-4.

[0033] like Figures 2 to 4 As shown, the balancing head 20 includes a housing 30, a rotor 32, a balancing correction mechanism 34, an AE sensor 36, and a control board 38.

[0034] The housing 30 is formed as a hollow cylinder parallel to the axial direction Ax. The housing 30 comprises a disk-shaped front end face 30a and a rear end face 30b, spaced apart along the axial direction Ax and perpendicular to it, and a cylindrical outer peripheral surface 30c parallel to the axial direction Ax. The outer peripheral surface 30c connects the peripheral edges of the front end face 30a and the rear end face 30b. Furthermore, the outer peripheral surface 30c is configured to be divisible into two parts along the axial direction Ax.

[0035] An electrically powered balancing correction mechanism 34 is housed in the space inside the housing 30. Additionally, a control board 38 and an AE sensor 36 are disposed within the wall forming the rear end face 30b.

[0036] The balance correction mechanism 34 includes two balance weights 34a and two sets of motor drive mechanisms 34b. Each balance weight 34a is held by a different motor drive mechanism 34b so that it can move freely about the axial direction θ with the axial direction Ax as the center. Each motor drive mechanism 34b is, for example, composed of a motor and multiple gears. Each motor drive mechanism 34b receives power from the control board 38, allowing each balance weight 34a to move independently about the axial direction θ. It should be noted that the balance correction mechanism 34 is not particularly limited to the structure shown in the figure, and various known types can be used.

[0037] The AE sensor 36 is an acoustic emission (AE) sensor, which is equivalent to the detection sensor of the present invention. The AE sensor 36 detects the high-frequency sound generated when the workpiece W, the dresser, or other contacted object comes into contact with the grinding stone 12, and outputs the sound detection signal to the control board 38.

[0038] The rotor portion 32 is disposed on the outer peripheral surface 30c and rotates integrally with the balancing head 20 in the axial direction θ. The rotor portion 32 is formed in a circumferential shape (about the axial direction θ) along the outer peripheral surface 30c, more specifically, in a ring shape (flange shape). A rotor coil 32a, which is a ring-shaped antenna coil, is disposed within the rotor portion 32. It should be noted that in this embodiment, the rotor portion 32 is integrally formed with the housing 30, but the rotor portion 32, which is formed independently of the housing 30, can also be fixed to the housing 30.

[0039] The rotor coil 32a is electrically connected to the control board 38, and via the control board 38, is electrically connected to the balance correction mechanism 34, etc. The rotor coil 32a receives drive power wirelessly transmitted (power transmission) from the stator 22 (described later) and drive commands wirelessly transmitted (information transmission) from the stator 22. Conversely, the rotor coil 32a wirelessly transmits (information transmission) the detection signal from the AE sensor 36 input from the control board 38 to the stator 22.

[0040] The control board 38 includes a processor (CPU, Central Processing Unit), power receiving circuits, power transmitting circuits, a receiving demodulation unit, and a transmitting modulation unit, and controls the operation of each part of the balancing head 20 and the power supply to each part. After converting the drive power (AC power) received by the rotor coil 32a into DC power, the control board 38 supplies this drive power to the balancing correction mechanism 34 and the AE sensor 36. Furthermore, the control board 38 outputs the drive commands received by the rotor coil 32a to the balancing correction mechanism 34. Additionally, the control board 38 controls the energization of the rotor coil 32a, enabling the detection signal from the AE sensor 36 to be wirelessly transmitted from the rotor coil 32a to the stator 22.

[0041] The stator 22 and the balancing head 20 are installed separately. The stator 22 functions as a transmitter that wirelessly transmits the drive power and drive commands from the balancing head 20 output from the controller 26 to the rotor 32, and conversely, it functions as a receiver that receives the detection signals from the AE sensor 36 wirelessly transmitted from the rotor 32 and outputs them to the controller 26. The stator 22 includes a stator ring 40, a transceiver control unit 42, and a signal cable 44.

[0042] The stator ring 40 is formed as a ring along the circumferential direction of the outer peripheral surface 30c. Specifically, the stator ring 40 is formed such that its inner diameter is larger than the outer diameter of the outer peripheral surface 30c, and it is fitted with a clearance (fitted outwards with a gap). In other words, the housing 30 passes through the space enclosed by the stator ring 40. Furthermore, the stator ring 40 is fixed in the axial direction Ax at a position opposite to and close to the rotor portion 32 by a fixing part (e.g., a mechanical guard) provided near the grinding device 10 located near the grinding stone 12. Thus, wireless transmission can be performed between the stator ring 40 and the rotor portion 32. A stator coil 40a, which is a ring-shaped antenna coil, is provided within the stator ring 40.

[0043] Under the control of the transceiver control unit 42 (described later), the stator coil 40a performs wireless transmission of drive power, drive commands, and detection signals to the rotor coil 32a.

[0044] The transceiver control unit 42 consists of a transmission modulator (transmitter) and a receiver demodulator. The transceiver control unit 42 is electrically connected to the controller 26 via a signal cable 44, and is also electrically connected to the stator coil 40a.

[0045] The transceiver control unit 42 controls the energization of the stator coil 40a based on the drive power input from the controller 26, thereby wirelessly transmitting the drive power to the rotor coil 32a using known methods such as electromagnetic induction, magnetic field resonance, and electric field resonance. Furthermore, the transceiver control unit 42 controls the energization of the stator coil 40a based on the drive command from the balance head 20 input from the controller 26, thereby wirelessly transmitting the drive command to the rotor unit 32 using known methods. Thus, drive power and drive commands are transmitted from the stator 22 to the balance head 20 in a non-contact manner.

[0046] Furthermore, the transceiver control unit 42 outputs the detection signal of the AE sensor 36 transmitted from the rotor coil 32a to the stator coil 40a in a non-contact manner to the controller 26.

[0047] Return to Figure 1 Vibration sensor 24 is mounted on spindle 14. Vibration sensor 24 is also connected to controller 26 via signal cable 50. Vibration sensor 24 detects low-frequency vibrations in the spindle 14 caused by the imbalance of the grinding stone 12 rotating at high speed with the help of spindle 14, and outputs the vibration detection signal to controller 26.

[0048] The controller 26 provides unified control over the supply of driving power to the balancing head 2, the driving of the balancing head 20, and the vibration detection based on the vibration sensor 24.

[0049] During the rotational drive of the grinding stone 12 based on the spindle 14, the controller 26 outputs drive power from the balancing head 20 to the transceiver control unit 42. Furthermore, while drive power is input from the controller 26, the transceiver control unit 42 controls the energization of the stator coil 40a, performing wireless transmission of drive power from the stator coil 40a to the rotor coil 32a. The drive power received by the rotor coil 32a is supplied to various parts of the balancing head 20 via the control board 38. As a result, the balancing head 20 and the AE sensor 36 become operational.

[0050] Next, the AE sensor 36 begins sound detection and continuously outputs sound detection signals to the control board 38. Furthermore, while the sound detection signal is being input from the AE sensor 36, the control board 38 controls the energization of the rotor coil 32a based on the sound detection signal, thereby wirelessly transmitting the sound detection signal from the rotor coil 32a to the stator coil 40a. The sound detection signal received by the stator coil 40a is output to the controller 26 by the transceiver control unit 42. Thus, the controller 26 can detect that the workpiece W, etc., has come into contact with the grinding stone 12 based on the sound detection signal.

[0051] Furthermore, during the rotational drive of the grinding stone 12 based on the spindle 14, the controller 26 activates the vibration sensor 24. Thus, a vibration detection signal is continuously input from the vibration sensor 24 to the controller 26. Each time a vibration detection signal is input from the vibration sensor 24, the controller 26 determines the configuration of the balancing weights 34a within the balancing correction mechanism 34, which can correct imbalances in the grinding stone 12 using known methods.

[0052] Next, the controller 26 generates a drive command for the balance correction mechanism 34 each time it determines the configuration of each counterweight 34a, and outputs the drive command to the transceiver control unit 42. Furthermore, the transceiver control unit 42 controls the energization of the stator coil 40a each time a drive command is input from the controller 26, and performs wireless transmission of the drive command from the stator coil 40a to the rotor coil 32a. The drive command received by the rotor coil 32a is input to the balance correction mechanism 34 via the control board 38. As a result, the balance correction mechanism 34 is driven according to the drive command, thereby correcting the imbalance of the high-speed rotating grinding stone 12.

[0053] Figure 5 This is an explanatory diagram used to illustrate the effect of the automatic balancer 16 of this embodiment relative to the automatic balancer 100 of the comparative example. (See diagram below.) Figure 5 As shown, the comparative example automatic balancer 100 includes a balancing head 102 and a stator 104, with a rotor 106 disposed on the front end face of the balancing head 102 via an adapter 102a. Furthermore, the stator 104 is disposed opposite the rotor 106. As a result, the balancing head 102, adapter 102a, rotor 106, and stator 104 are arranged in parallel along the axial direction Ax, thereby increasing the length LA of the automatic balancer 100.

[0054] In this embodiment, the automatic balancer 16 has an annular stator ring 40 provided on the stator 22. This stator ring 40 is fitted with the outer peripheral surface 30c of the balancing head 20 with clearance. This allows the rotor portion 32 to be formed on the outer peripheral surface 30c, eliminating the need for the adapter 102a of the comparative example. As a result, the overall length LB of the automatic balancer 16 in the axial direction Ax is equal to the length of the balancing head 20 alone in the axial direction Ax, significantly reducing the length in the axial direction Ax compared to the comparative example. This saves space in the grinding apparatus 10 by reducing the installation space of the automatic balancer 16. Furthermore, it eliminates the need to modify the housing housing the grinding stone 12 to accommodate the automatic balancer 16 within the grinding apparatus 10.

[0055] In the above embodiment, the outer peripheral surface 30c of the housing 30 is formed into a cylindrical shape. However, as long as the housing 30 can rotate in the axial direction θ within the space enclosed by the stator ring 40, the outer peripheral surface 30c can also be formed into a cylindrical shape other than a cylindrical shape. In addition, in the above embodiment, the rotor portion 32 (rotor coil 32a) and the stator ring 40 (stator coil 40a) are each formed into a ring shape. However, as long as wireless transmission between the rotor coil 32a and the stator coil 40a is possible, it can also be formed into a shape other than a ring, such as a quadrilateral ring (polygonal ring).

[0056] In the above embodiment, the rotor portion 32 and the stator ring 40 are each formed in a ring shape. However, as long as the shape is along the circumferential direction (around the axis direction θ) of the outer peripheral surface 30c, it is not limited to a ring shape, and can also be formed in, for example, an arc shape or a semi-ring shape. It should be noted that in order to enable wireless transmission of drive power and the like between the rotor portion 32 and the stator ring 40 at all times, it is desirable that either the rotor portion 32 or the stator ring 40 be a ring shape.

[0057] In the above embodiment, the rotor portion 32 is disposed on the outer peripheral surface 30c and is positioned opposite the stator ring 40 in the axial direction Ax. However, for example, the rotor portion 32 may also be formed on the outer peripheral surface 30c and positioned opposite the inner peripheral surface of the stator ring 40, that is, the area in the outer peripheral surface 30c surrounded by the stator ring 40.

[0058] In the above embodiment, an automatic balancing device 16 for correcting the imbalance of the grinding stone 12 of the grinding apparatus 10 was described as an example. However, the present invention can also be applied to automatic balancing devices used in correcting the imbalance of various rotating bodies in semiconductor manufacturing apparatuses other than the grinding apparatus 10. Furthermore, the present invention can also be applied to correcting the imbalance of various rotating bodies in fields other than semiconductor manufacturing apparatuses.

[0059] Explanation of reference numerals in the attached figures

[0060] 10: Grinding device; 12: Grinding stone; 14: Spindle; 14a: Rotary shaft; 16: Automatic balancer; 20: Balancing head; 22: Stator; 24: Vibration sensor; 26: Controller; 28: Adapter flange; 30: Housing; 30a: Front end face; 30b: Rear end face; 30c: Outer peripheral surface; 32: Rotor section; 32a: Rotor coil; 34: Balancing correction mechanism; 34a: Balancing counterweight; 34b: Motor drive mechanism; 36: AE sensor; 38: Control board; 40: Stator ring; 40a: Stator coil; 42: Transceiver control section; 44, 50: Signal cable; 100: Automatic balancer; 102: Balancing head; 102a: Adapter; 104: Stator; 106: Rotor; Ax: Axial direction; θ: Orbital direction; W: Workpiece.

Claims

1. An automatic balancer wherein, the automatic balancer is provided with: a balance head that rotates integrally with a rotating body with a rotating shaft of the rotating body as a center, has an electric type balance correction mechanism that corrects an unbalance of the rotating body, and has a housing that has a cylindrical outer peripheral surface parallel to the rotating shaft and accommodates the balance correction mechanism; a stator that is provided separately from the balance head, has a shape along a circumferential direction of the outer peripheral surface in a state where a gap is provided from the outer peripheral surface, and is electrically connected to a controller of the balance head; and a rotor portion that is provided at a position on the outer peripheral surface opposite to the stator, rotates integrally with the balance head, has a shape along the circumferential direction of the outer peripheral surface, and is electrically connected to the balance correction mechanism, wireless transmission is possible between the stator and the rotor portion, the stator and the rotor portion are opposite to each other in an axial direction of the rotating shaft, the stator is formed in a ring shape along the circumferential direction of the outer peripheral surface, and is play-fitted to the outer peripheral surface.

2. The automatic balancer according to claim 1, wherein, the rotor portion is formed in a ring shape along the circumferential direction of the outer peripheral surface.

3. The automatic balancer according to claim 1 or 2, wherein, the stator wirelessly transmits driving power and a driving command of the balance head output from the controller to the rotor portion, the rotor portion receives the driving power and the driving command from the stator, the balance correction mechanism operates based on the driving power and the driving command received by the rotor portion.

4. The automatic balancer according to claim 1 or 2, wherein, the automatic balancer is provided with a detection sensor that is provided to the housing, detects contact of a contacted object to the rotating body, the rotor portion wirelessly transmits a detection signal of the detection sensor to the stator, the stator inputs the detection signal received from the rotor portion to the controller.

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