CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This international application claims the benefit of each of US App. No.: 18/305,432, filed April 24, 2023, which is a continuation of and claims priority to US App. No.: 17/935,173, filed September 26, 2022, the entire contents of which are incorporated here by reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to tool detectors and, more particularly, to a brushless tool detector and a method of use therefor.

[0003] Presently, tool detectors, specifically those with direct current (DC) brushed motors, fail due to a formation of dead spots on a commutator. This is primarily due to the accumulation of carbon particles around the edges of a commutator bar thus causing a commutator permanent damage, particularly in applications where DC brush motors rotate less than one revolution and/or reciprocates (forward and backward rotation at short intervals) or sits at a particular spot, under power, for long periods of time between cycles. Those conditions, individually or in combination, result in premature failure of the motor due to the commutator developing dead spots that in essence make the DC brush motor inoperable.

[0004] Additionally, external controls, typically required to operate DC motor driven systems, are cumbersome and take up valuable space in an electrical control cabinet. Moreover, a DC brush motor has limited detection sensitivity due to a lack of full servo loop control. [0005] A Permanent Magnet Synchronous Motor (PMSM), such as an AC brushless motor and/or a brushless DC-servomotor, lacking brushes and commutator, is not subjected to all issues relating to commutation including premature failure, a typical problem shown in DC brushed motors.

[0006] As can be seen, there is a need for a detection sensor as a tool detector utilizing a “PMSM” motor and a method for using such in place of a DC brush motor.

SUMMARY OF THE INVENTION

[0007] In one aspect of the present invention, a detection sensor includes a permanent magnet synchronous motor (PMSM) such as an alternating current (AC) PMSM or a direct current (DC) servomotor-type PMSM housed in a casing, a motherboard and an AC or DC servo controller with a permanent memory in electronic communication with the PMSM, and a shaft extending from the PMSM configured to rotate a sensing needle wherein the sensing needle is configured to sense an object in its rotation.

[0008] Advantageously, the present invention may eliminate all the issues related to dead spots typical of similar style tool monitoring devices that operate with brush style motors. It may increase consistency and longevity of a motor particularly in an application where the motor can only rotate less than one revolution and/or in a reciprocal motion, or has to sit in a particular spot, under power, for an extended period between cycles.

[0009] It can also be operated in harsh environments and may be utilized where free space monitoring is a requirement.

[0010] The present invention may fill a need for multiple sensors combined into a single machine tool still maintaining individual set parameters for each of the sensors. [0011] Furthermore, by bending or conforming a sensing needle of the present invention to accommodate a specific application, it may monitor the presence or absence of a part or a hole in a robotic or automated assembly operation during unattended operation.

[0012] The PMSM may rotate by a fraction of a full revolution, without failure due to brush decay, thus maintaining controlled rotation, velocity, and torque.

[0013] The device may have a fully integrated control which may include an internally mounted motherboard and a drive such as a servo drive controller that is attached to the motherboard, operate without a gear box, be controlled directly from a machine tool control, and be daisy chained, in some embodiments up to 127 sensors/sy stems, all individually and simultaneously communicating with the machine tool without a need for an external control. The device may have at least partially integrated control components, for example, an internally mounted drive such as a servo drive controller that is encapsulated and attached directly onto the back of the PMSM. An external motherboard may communicate with the servo drive controller and be mounted within its own enclosure, outside of the device and, e.g., within a machine tool electrical cabinet while reducing the amount of space within the cabinet compared to fully external control systems.

[0014] These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a perspective view of a sensor according to an embodiment of the present invention; [0016] FIG. 2 is a perspective view thereof with a casing and isolating shield omitted;

[0017] FIG. 3 is an exploded view of the sensor of Figure 1 detailing internal components;

[0018] FIG. 4 is a cross sectional view on line 4-4 of Figure 1;

[0019] FIG. 5 is a top view of the sensor showing a rotation;

[0020] FIG. 6 is a top view thereof showing a tool detection;

[0021] FIG. 7 is a perspective view of a variant of the sensor of Figure 1 ;

[0022] FIG. 8 is perspective view of the sensor of Figure 7 with a casing omitted;

[0023] FIG. 9 is an exploded view of the sensor of Figure 7 detailing internal components;

[0024] FIG. 10 is a perspective cross sectional view of portions of the sensor of Figure 7; and

[0025] FIG. 11 is a cross sectional view of additional portions of the sensor of Figure 7.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims with reference to the drawings.

[0027] A general overview of the various features of the invention will be provided, with a detailed description following. Broadly, an embodiment of the present invention provides a device shown as a detection tool or a sensor 5 A (FIGS. 1-6), 5B (FIGS. 7-9) utilizing a permanent magnet synchronous motor (PMSM), which may be an alternating current (AC) brushless motor or a brushless direct current (DC) servomotor. The detection sensor may be implemented with an integrated drive or servo drive controller, such as an integrated AC servo drive controller or an integrated DC servo drive controller. The sensor controls may be fully integrated by way of an internal motherboard within the sensor which may be connected to the servo drive controller or may be partially integrated with an external motherboard that communicates with the internal servo drive controller. The sensor may be a Positive Contact Sensor (PCS) with Extreme Range (ER).

[0028] The integrated servo drive controller may enable highly sensitive, low impact detection, and may remove a need for various external controls, typically required to operate conventional DC brush motors which are often entirely mounted in large enclosures that occupy substantial space within an electrical control cabinet. [0029] The PMSM may be integrated into a body or casing. The body may be metal and sized to house the motor as well as the integrated AC servo drive controller. In some implementations, the body may be less than 100mm in length and 19mm in diameter, equipped with non-volatile memory to store all detection parameters and control settings. In some implementations, such as detection sensor 5A with an internally integrated motherboard, its body may have a length of less than about 115mm and a width (diameter) of less than about 30mm, typically a length of less than about 110mm and a width (diameter) of less than about 25mm, and may provide a length-to-width ratio of about 5:1 with a length of 105mm and width (diameter) of 21mm. In some implementations, such as detection sensor 5BA with an external motherboard, its body may have a length of less than about 105mm and a width (diameter) of less than about 35mm, typically a length of less than about 100mm and a width (diameter) of less than about 30mm, and may provide a length-to-width ratio of about 4:1 with a length of 95mm and width (diameter) of 24mm. With a proper connection to the outside, the device could function in a harsh and coolant flooded environment while being controlled and communicating to a connected machine tool control. The device may communicate, for example by CANopen® technology, which may enable simple communication with machine controls and networking of multiple sensors, all operating at the same time and with individually set parameters. Devices may be daisy chained, connected together, to be controlled individually. A user would be able to send to and receive from each device specific information to and from the device, thus having the machine tool that incorporates such devices act accordingly, based on the information sent and received. With the communication technology, the sensor may react to certain error conditions or influence, and the user may control the network in accordance with findings of the sensor.

[0030] The detection sensor may include an absolute encoder outfitted onto the PMSM to provide feedback information for speed and position by outputting a digital word or bit in relation to motion. The absolute encoder may be mounted directly on the back of the PMSM and enable accurate position setting and reference, maintaining set parameters in the servo controller’s permanent memory for easy and flexible installation and recall of various previously set configurations. The encoder enables elimination of internal or external stops or reference for a "Home" position, and it is necessary to be able to know the actual rotational position even after a power failure or at start up after the machine has been powered down at the end of a shift. Alternatively, instead of an absolute encoder, the position sensing may be achieved by way of Hall sensors such as analog Hall sensors that are integrated into the servo drive controller incorporated at the back of the motor and the various, e.g., set parameters may be stored in permanent memory of the external motherboard. In detection sensors that implement Hall sensors, its home position may be automatically learned at start up and immediately ready to learn the position to be monitored. An external mechanical stop may be configured for use as the initial home position. [0031] The integrated PMSM and servo-controlled sensor may be fitted onto any machine tool to detect a broken or missing tool or object.

[0032] In some embodiments, a gearbox may be mounted on a front of the unit, such as directly on top of the motor, so that a shaft coming out of the of the sensor body would be the shaft coming out the gearbox that is mounted directly onto the motor. Rotation may then be converted into a linear motion, enabling accurate measurement and/or probing of objects or cavities at a right angle to it, at a relatively long distance or depth from the sensor itself.

[0033] In some embodiments, the device may be daisy chained, up to 127 sensors/sy stems all individually and simultaneously communicating with the machine tool without a need for an external control.

[0034] Referring now to the Figures, FIGS. 1-4 and 7-11 respectively detail detection sensors 5A, 5B according to embodiments of the present invention. Each of sensors 5 A, 5B is shown with a permanent magnet synchronous motor (PMSM) 16. Referring now to FIGS. 1-4, sensor 5 A is represented here with an AC PMSM 16A that is held within a casing 28A by mounting screws 30 and mounting screw O-rings 31. The PMSM 16 is controlled by a control device such as an integrated servo controller 20, represented here as an integrated AC servo controller 20A and a motherboard 22 A that is attached directly to an absolute encoder 18. These components 20A, 22A, and 18 are contained inside an isolating shield 26 and encapsulated in the casing 28 A. The PMSM 16 rotates a motor shaft 14. The absolute encoder 18 monitors the angular position of the PMSM 16. The AC servo controller 20A attaches to the motherboard 22A. An end of the motherboard 22A attaches to a connector 24, which is secured in a connector housing 34. Connector 24 includes conductive pins 25 that are molded inside the connector 24 and attach to a wire or cable, typically a multi-wire cable such as, e.g., a five-wire cable for power and/or signal transmission. Connector 24 further includes a key 27 that is defined by a plastic web of material to ensure proper orientation of the cable by being received in a corresponding slot in the cable’s connector. The integrated AC servo controller 20A and the motherboard 22A communicate electronically with a machine tool via CANopen® protocol through the plurality of pins 25, molded inside the connector 24. [0035] A top cap 12 attaches to the motor shaft 14 protruding out of the end of the casing 28 A. A sensing needle 10 is attached to the top cap 12 and is driven by the motor shaft 14. A seal pack includes a first seal 32 that is outside of the casing 28 A and is wedged at a predetermined compression between an outer surface of the casing 28A and a top seal retaining ring 33 and a second seal 29 that is inside of the casing 28 A is wedged between the PMSM 16 and an inner surface of the casing 28 A. An O- Ring 36 seals a second end of the casing 28A. These ensure internal components 16, 18, 26, 20A, 22A, 24 inside the casing 28 A are sealed against external contaminates thus conforming to an IP67 rating for liquid infiltration. A retaining clip 38 holds the internal components 16, 18, 26, 20A, 22 A, 24 in place inside of the casing 28 A.

[0036] Figures 5 and 6 detail a rotation of the sensing needle 10. The sensing needle may contact an object 40 at a learned position, alerting the device as to the presence or a change in presence of the object 40.

[0037] According to method steps of the present invention, the sensing needle 10 may learn or record its home position. The sensing needle may then locate or sense tools or objects to be detected by rotating clockwise or counterclockwise. The sensing needle 10 may learn a position of the object 40 by rotating in one direction or both directions. If rotating in both directions, the sensing needle 10 may learn two different positions of the object being monitored or two different objects, for example a front face and a rear face. The newly learned position(s) of the object is utilized with the previously learned and established home position. These parameters are stored directly into the sensor’s own permanent memory that is integrated in the AC servo controller 20A and the motherboard 22A. These functions are achieved by deploying software such as “Adaptive Touch Technology®” (“ATT”) software, integrated into the AC servo controller 20A and the motherboard 22A. The software may properly control all the function and full operation of the PMSM brushless motor as it is used as a monitoring device, with all its sophistication needed to detect, in the case of very small tools as example, tools as small as 0.2mm in diameters without damaging the sensor (or parts thereof) or the object therefore being very soft in touch yet very fast reacting and very precise. The software may enable learning a home position, learning about an object in a clockwise direction or counterclockwise direction or both, and for every sensor, in the case multiple sensors are daisy chained together up to a max of 127 sensors, set and learn specific parameters for each of the sensors.

[0038] After completing this initial learning process, the sensing needle 10 may begin its monitoring function. The present invention monitors for a change in position of the object 40 by rotating the sensing needle 10 and comparing a radial location of the sensing needle to the initially detected object position.

[0039] The integrated servo controller 20 receives the start signal, provided to the servo controller 20 directly from a machine control, and communicated via the integrated CANopen® protocol through the plurality of pins located inside the connector 24, the sensing needle 10 then begins its rotation in one direction. The present invention may adapt to any machine control. Each machine tool (a lathe, a rotary transfer machine, a mill, etc.) made may have their own commercially standard control, such as a proprietary control or even a standard control platform with an integrated proprietary control feature on top of the standard control platform. The sensing needle 10 may then rotate in the opposite direction if programmed to do such. The sensing needle 10 rotates in accordance with the parameters previously set and stored in the permanent memory of the integrated AC servo controller 20A and the motherboard 22A dictating torque, velocity, and sensitivity. Through, for example, its software implementation, the system has the capability to determine if, in fact, the sensing needle 10 has returned to its home position. Therefore, the software is also monitoring the return cycle, and looks for the home position to be reached after a detecting cycle. In other words, if an obstruction prevents the sensing needle 10 from returning to its home position in the predetermined/ expected time period such that the home position is never reached, the system will issue a fault condition to caution the user something went wrong, such as the presence of an obstruction or in any case an external factor prevented the completion of this particular cycle.

[0040] As the sensing needle 10 is about to approach the object 40, acting in accordance with the algorithms being analyzed by the ATT software stored in its permanent memory of the integrated AC servo controller 20A and the motherboard 22A, it may slow down or decelerate in accordance with the parameters previously set, taking into consideration the size of the object 40 being monitored. The sensing needle 10 may contact the object 40 without causing damage to the sensing needle 10 or object 40.

[0041] The integrated servo controller 20, having detected a change of status, such as a stop in rotation caused by the sensing needle 10 contacting the object 40 utilizes its closed-loop communication technology and immediately begins rotation in the opposite direction and returns to the sensing needle 10 to its home position. The integrated servo controller 20, being the device that controls and monitors functions of the brushless motor, detects a change in the state as the rotation is stopped prematurely or the rotation has in fact reached the predetermined location previously set during the teach function where the system learns the specific position of the object to be detected. The system in accordance with a programmable preset "window", a range in the plus or minus form the actual position of the object, determines if the position was reached. With the closed-loop communication technology, at all times the servo controller and the motor know what one another are doing and at what state of the operation one is in versus the other. Therefore one does not have to rely on getting a specific signal back from a device and having to acknowledge that information for every step of the operation but instead the communication is constant. Closed-loop refers to a continuous cycle of information always and constantly updated without the need to actually prompt a send command.

[0042] The integrated AC servo controller 20A and the motherboard 22A may communicate directly through CANopen® technology via the connector 24 with the machine tool, without additional external controls. Based on conditions sensed by the sensing needle, the machine tool may be instructed to continue to operate or immediately pause its operation. The machine tool may be any machine such as a lathe, a rotary transfer machine, a mill a machining center, an assembly machine, or any machine the sensor may be coupled with to monitor a specific object for presence or absence or monitor a feature, in the case of monitoring the presence or absence of a hole.

[0043] If the sensing needle 10 reaches an area or areas where the object 40 is expected to be found, and instead the sensing needle 10 goes past the learned position (for example, if the object 40 is broken or missing), the system will instantly determine a change in condition from what was originally learned during setup and stored in the integrated AC servo controller 20A and the motherboard 22A. The sensing needle may immediately return to its home position, and through its integrated CANopen® technology, the sensing needle 10 may communicate the abnormal finding via the connector 24 to the machine tool. The machine tool may determine if it should continue its operation, stop, or in any case act in accordance with predetermined set parameters.

[0044] The present invention may similarly be utilized to monitor free space. For example, the sensing needle 10 may contact an object 40, triggering an abnormal finding and communicating such to the machine tool. The sensing needle 10 would return to its home position, and the sensor would wait for a new start signal to be sent and consequently received by its integrated AC servo controller 20A and the motherboard 22A.

[0045] Utilizing the CANopen® protocol, multiple sensors may be linked together and each individual sensor, with its own set parameters stored in each individual sensor integrated AC servo controller 20A and the motherboard 22A, can operate independently, and output its own individual monitoring results through the individual connector 24, all communicating at the same time with a machine tool control.

[0046] Referring now to FIGS. 7-11, detection sensor 5B is substantially the same as detection sensor 5A in its components, construction, and use, whereby the above description(s) are applicable here, with detection sensor 5B differing from detection sensor 5A in, e.g., the following ways. Casing 28B is shown with a smaller ratio of length-to- width and relatively shorter and wider (greater diameter) than casing 28 A. PMSM 16 is represented here as a brushless DC servomotor-type PMSM 16B. Instead of absolute encoder 18, detection sensor 5B is shown having its position sensing achieved by way of Hall sensors 19, which may be analogue Hall sensors that are integrated into the servo controller 20. Servo controller 20 is represented here as a DC servo controller 20B. DC servo controller 20B is shown incorporated at the back of the brushless DC servomotor PMSM 16B.

[0047] Still referring to FIGS. 7-11, motherboard 22B is arranged outside of the casing 28B and sensor 5B and instead mounted inside of an external control module, such as motherboard enclosure 50. In this configuration, sensor 5B may store its data or information externally, such as in permanent memory of the motherboard 22B, which is in electronic communication with the DC servo controller 20B, typically by way of conductors such as wires. Accordingly, in sensor 5B, the CANopen® protocols or communications may be accomplished offboard the sensor 5B body itself but instead through its external motherboard 22B. Motherboard enclosure 50 is typically mounted within a machine tool electrical cabinet 52 and is represented here with a DIN style configuration, including a slot 54 that may receive a DIN rail for mounting the motherboard enclosure 50 to the DIN rail.

[0048] Still referring to FIGS. 7-11, sensor 5B is shown without an isolating shield 26 such as that of sensor 5A. In sensor 5B, its DC servo controller 20B may be fully encapsulated and integrated directly at the back of back of PMSM 16 and the motherboard 22B is external, which may obviate a need for supplemental shielding from isolating shield 26.

[0049] Still referring to FIGS. 7-11, sensor 5B may implement a mechanical stop mechanism to facilitate defining the sensing needle’s 10 home position. Referring now to FIGS. 9-10, this may include a blind bore 60 that extends upwardly into a lower surface of the top cap 12. A set screw 62 is threadedly received in the blind bore 60 an extends slightly below the lower surface of the top cap 12, as a cap projection. At an upper end face of the body or casing 28B, a set screw bore(s) 64 threadedly receives another set screw(s) 62, which extends slightly above the upper surface or upper end face of casing 28B. These cap and casing set screws 62 are aligned with each other about the arc that the cap set screw 62 sweeps during rotation of the top cap 12 so that the fixed casing set screw 62 mechanically prevents further movement of the cap set screw 62 as a mechanical stop. The mechanical stop along with the system’s software implementation allow the system to assure the automatically detected home position which is achieved by the rotation of the top cap 12 during a power-up event. Rotation of the top cap 12, clockwise or counterclockwise depending on, e.g., a position of a DIP (dual inline package) switch as predetermined, rotates the top cap until the cap and casing set screws engage each other, defining the home position at power-up.

[0050] It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.