阅读说明：本技术 力感应式回转驱动器 (Force sensing type rotary driver ) 是由 A·P·普莱斯尼克 于 2019-09-27 设计创作，主要内容包括：传感器用于测量施加到回转驱动器的转矩。回转驱动器包括蜗杆和蜗轮,并且传感器与固定装置耦合,该固定装置用于将蜗杆固定到回转驱动器壳体。传感器产生指示蜗轮的转矩的信号。蜗杆通过第一轴承和第二轴承固定到回转驱动器壳体。两个端板和八个螺栓也用于进一步将蜗杆和轴承固定到回转驱动器壳体。通过拧紧螺栓,通过轴承将压缩力施加到蜗杆上。蜗轮上施加的转矩在蜗杆上引起轴向力。轴向力通过蜗杆、轴承、端板和螺栓传递。可以将一个或多个传感器嵌入到端板或螺栓中的一个或多个,以测量端板或螺栓中归因于轴向力的应变。控制装置接收来自传感器的信号,并存储、分析和/或传递该信号。(The sensor is used to measure the torque applied to the slew drive. The slew drive includes a worm and a worm gear, and the sensor is coupled with a fixture for securing the worm to the slew drive housing. The sensor generates a signal indicative of the torque of the worm gear. The worm is secured to the slew drive housing by a first bearing and a second bearing. Two end plates and eight bolts are also used to further secure the worm and bearing to the slew drive housing. By tightening the bolts, a compressive force is applied to the worm through the bearing. The torque applied on the worm gear causes an axial force on the worm. Axial forces are transmitted through the worm, bearings, end plates and bolts. One or more sensors may be embedded in one or more of the end plates or bolts to measure strain in the end plates or bolts due to axial forces. The control device receives the signal from the sensor and stores, analyzes and/or transmits the signal.)

1. A slew drive comprising:

(a) a rotary drive housing;

(b) a worm comprising a central threaded portion;

(c) a worm gear including worm gear teeth for meshing with a central threaded portion of the worm;

(d) a fixing means for fixing the worm to the rotary drive housing; and

(e) a sensor coupled with a fixture;

wherein the sensor is configured to sense a load of the fixture responsive to a torque of the worm gear and to generate a signal indicative of the torque of the worm gear.

2. The rotary drive of claim 1, wherein the securing device is one of a distal plate, a bolt, a threaded plug, and a retaining ring.

3. The slew drive of claim 1 where the sensor is one of an electrical strain gauge and an optical strain gauge.

4. The slew drive of claim 1 further comprising:

(f) a control device coupled with the sensor;

wherein the control device is configured to receive the signal from the sensor and at least one of store, analyze and transmit the signal.

5. The swing drive of claim 4, wherein the control apparatus comprises a processor including programming code stored in a storage device of the processor and executable on the processor, wherein the processor further comprises: an analog-to-digital converter (ADC) to digitize a signal at a sampling rate of the ADC and generate a digital signal; a communication module for at least one of receiving or transmitting radio waves, and wherein the processor is configured to at least one of store, analyze, and transmit at least one of signals and digital signals.

6. The slew drive of claim 5 where the processor is configured to transmit at least one of the signals and the digital signals to a remote computer system through a communication module.

7. The slew driver of claim 5 where the processor is configured to construct a histogram of the digital signal.

8. The swing drive of claim 5, wherein the processor is configured to calculate an average of the digital signal over a predetermined period of time, the average being indicative of an average of the torque of the worm gear.

9. The swing drive of claim 8 wherein the processor is configured to transmit the average value to a motor controller through a communication module.

10. The swing driver of claim 5, wherein the processor is configured to calculate a frequency spectrum of the digital signal, the frequency spectrum indicating a time varying function of a torque of the worm gear.

11. The swing drive of claim 10 wherein the processor is configured to transmit the frequency spectrum to the motor controller through the communication module.

12. The slew drive of claim 5 where the communication modules comprise at least one of wired communication modules and wireless communication modules.

13. A method for monitoring and controlling a slew drive, comprising:

(a) providing a rotary driver housing;

(b) providing a worm comprising a central threaded portion;

(c) providing a worm gear including worm gear teeth for meshing with a central threaded portion of the worm;

(d) providing a fixing means for fixing the worm to the slew drive housing; and

(e) providing a sensor, the sensor coupled to a fixture;

wherein the sensor is configured to sense a load of the fixture responsive to a torque of the worm gear and to generate a signal indicative of the torque of the worm gear.

14. The method of claim 13, further comprising:

(f) providing a control device, the control device being coupled to the sensor;

wherein the control device is configured to receive the signal from the sensor and at least one of store, analyze and transmit the signal.

15. A slew drive comprising:

(a) a rotary drive housing;

(b) a first distal plate comprising one or more first apertures;

(c) a second distal panel comprising one or more second apertures;

(d) a worm comprising a central threaded portion, a first distal shaft portion having a first shoulder, and a second distal shaft portion having a second shoulder;

(e) a first bearing disposed on the first distal shaft portion and abutting the first shoulder and the first distal plate;

(f) a second bearing disposed on the second distal shaft portion and abutting the second shoulder and the second distal plate;

(g) a worm gear including worm gear teeth for meshing with a central threaded portion of the worm;

(h) one or more first bolts inserted through the one or more first holes for securing the worm and the first bearing to the slew drive housing;

(i) one or more second bolts inserted through the one or more second holes for securing the worm and the second bearing to the slew drive housing; and

(j) a sensor coupled to one of:

(1) one of the one or more first bolts and the one or more second bolts; and

(2) one of the first distal plate and the second distal plate;

wherein the sensor is configured to sense a load of one of the following in response to a torque of the worm gear:

(A) one of the one or more first bolts and the one or more second bolts; and

(B) one of the first distal plate and the second distal plate;

and generates a signal indicative of the torque of the worm gear.

16. The slew drive of claim 15 where the sensor is embedded in the center of one of the following:

(I) one or more first bolts and one or more second bolts; and

(II) a first distal panel and a second distal panel.

17. The slew drive of claim 15 further comprising:

(k) a control device coupled with the sensor;

wherein the control device is configured to receive the signal from the sensor and at least one of store, analyze and transmit the signal.

18. The slew drive of claim 17 where the slew drive comprises: a first distal plate comprising four first apertures; a second distal plate comprising four second apertures; four first bolts inserted through the four first holes; four second bolts inserted through the four second holes; four sensors, wherein two of the four sensors are coupled with two of the four first bolts and two other of the four sensors are coupled with two of the four second bolts; and a control device coupled to the four sensors, wherein each of the four sensors is configured to sense a load of each of the two of the four first bolts and the two of the four second bolts and generate a signal indicative of a torque of the worm wheel in response to the torque of the worm wheel, and wherein the control device is configured to receive the signal from each of the four sensors and at least one of store, analyze, and transmit the signal.

19. The slew drive of claim 18 where the control means comprises: a processor comprising programming code stored on a storage device of the processor and executable on the processor, wherein the processor further comprises: an analog-to-digital converter (ADC) to digitize a signal from each of the four sensors at a sampling rate of the ADC and to generate a digital signal corresponding to each of the four sensors; and a communication module for at least one of receiving or transmitting radio waves, and wherein the processor is configured to at least one of store, analyze, and transmit at least one of a signal and a digital signal corresponding to each of the four sensors.

20. The slew driver of claim 19 where the processor is configured to construct a histogram of the digital signals corresponding to each of the four sensors.

21. The swing drive of claim 19, wherein the processor is configured to calculate an average of the digital signals corresponding to each of the four sensors over a predetermined period of time, the average being indicative of an average of the torque of the worm gear.

22. The swing drive of claim 21 wherein the processor is configured to transmit the average value to a motor controller through a communication module.

23. The swing driver of claim 19 wherein the processor is configured to calculate a frequency spectrum of the digital signal corresponding to each of the four sensors, the frequency spectrum being indicative of a time varying function of the torque of the worm gear.

24. The swing drive of claim 23 wherein the processor is configured to transmit the frequency spectrum to the motor controller through the communication module.

Technical Field

The present invention relates to a rotary drive that uses one or more sensors to determine the torque applied to the rotary drive. In particular, the slew drive comprises a housing, a worm wheel and a fixture, and the slew drive may be equipped with one or more sensors to sense the torque exerted on the worm wheel. Each sensor generates a signal indicative of torque. A control device may be used to receive the signal from the sensor and selectively store, analyze and/or transmit the signal.

Background

A swing drive is a mechanism that is typically used to rotate an external unit by applying a torque at a relatively low rotational speed. Rotary drives are used in a variety of applications, including solar trackers, wind turbines, and heavy vehicles. The rotary drive includes a worm and a worm gear. The worm gear and worm are housed within a rotary drive housing. The housing comprises two ends at which two bearings, for example two tapered roller bearings, are arranged. The worm is fixed to the housing by two bearings. The central threaded portion of the worm meshes with the teeth of the worm wheel. The worm gear is coupled with an external unit and applies torque to rotate it at the above rotational speed. The slew drive also utilizes two end plates and a plurality of bolts (typically four on each side) to further secure the worm and tapered roller bearings to the slew drive housing. This is achieved by tightening bolts on both sides which exert an axial compressive force on the worm. The bolts are also subjected to equal but opposite forces. Thus, a tensile force is generated in each bolt.

It is desirable to measure the torque of the worm gear as a function of time and use this data for real-time monitoring and control and/or future processing. The worm wheel is subjected to a torque exerted on the external unit, but in the opposite direction. The torque on the worm wheel is represented as an axial force in the worm. The present invention uses one or more sensors to sense the axial force experienced by the worm to measure torque. In particular, the sensor may be embedded in a fixing means, such as an end plate or a bolt. The sensor is configured to sense a load of the fixture responsive to a torque of the worm gear and to generate a signal indicative of the torque of the worm gear. The control device is used for receiving the signals and storing, analyzing and/or transmitting the signals to the outside.

Disclosure of Invention

In one aspect, a swing drive is disclosed, wherein the swing drive includes a swing drive housing; a worm comprising a central threaded portion; a worm gear including worm gear teeth for meshing with a central threaded portion of the worm; a fixing device for fixing the worm to the rotary drive housing; and a sensor coupled to the fixture, wherein the sensor is configured to sense a load of the fixture responsive to a torque of the worm gear and to generate a signal indicative of the torque of the worm gear.

Preferably, the securing means is one of a distal plate, a bolt, a threaded plug and a retaining ring.

Preferably, the sensor is one of an electrical strain gauge and an optical strain gauge.

Preferably, the slew drive further comprises a control device coupled to the sensor, wherein the control device is configured to receive the signal from the sensor and to perform at least one of storage, analysis and transmission of the signal.

Preferably, the control apparatus comprises a processor comprising programming code stored on a storage device of the processor and capable of running on the processor, wherein the processor further comprises: an analog-to-digital converter (ADC) to digitize the signal at a sampling rate of the ADC and generate a digital signal; a communication module for at least one of receiving and transmitting radio waves, and wherein the processor is configured to at least one of store, analyze, and transmit at least one of the signals and the digital signals.

Preferably, the processor is configured to transmit at least one of the signal and the digital signal to a remote computer system through the communication module.

Preferably, the processor is configured to construct a histogram of the digital signal.

Preferably, the processor is configured to calculate an average of the digital signal over a predetermined period of time, the average being indicative of an average of the torque on the worm gear.

Preferably, the processor is configured to transmit the average value to the motor controller via the communication module.

Preferably, the processor is configured to calculate a frequency spectrum of the digital signal, the frequency spectrum being indicative of a time varying function of the torque on the worm gear.

Preferably, the processor is configured to transmit the frequency spectrum to the motor controller via the communication module.

Preferably, the communication module includes at least one of a wired communication module and a wireless communication module.

In another aspect, a method of monitoring and controlling a slew drive is disclosed, wherein the method comprises: providing a rotary driver housing; providing a worm comprising a central threaded portion; providing a worm gear including worm gear teeth for meshing with the central threaded portion of the worm; providing a fixing means for fixing the worm to the slew drive housing; and providing a sensor coupled to the fixture, wherein the sensor is configured to sense a load of the fixture responsive to a torque of the worm gear and to generate a signal indicative of the torque of the worm gear.

Preferably, the method further comprises providing a control device coupled to the sensor, wherein the control device is configured to receive the signal from the sensor and to perform at least one of storage, analysis and transmission of the signal.

In another aspect, a swing driver is disclosed, wherein the swing driver comprises: a rotary drive housing; a first distal plate comprising one or more first apertures; a second distal plate comprising one or more second apertures; a worm comprising a central threaded portion, a first distal shaft portion having a first shoulder, a second distal shaft portion having a second shoulder; a first bearing disposed on the first distal shaft portion and adjacent to the first shoulder and the first distal plate; a second bearing disposed on the second distal shaft portion and abutting the second shoulder and the second distal plate; a worm gear including worm gear teeth for meshing with a central threaded portion of the worm; one or more first bolts inserted through the one or more first holes for securing the worm and the first bearing to the slew drive housing; one or more second bolts inserted through the one or more second holes for securing the worm and the second bearing to the slew drive housing; and a sensor coupled to one of the following: one of the one or more first bolts and one or more second bolts, one of the first distal plate and the second distal plate, wherein the sensor is configured to sense a load of one of the following in response to a torque on the worm gear: one of the one or more first bolts and the one or more second bolts; one of the first distal plate and the second distal plate to, and generate a signal indicative of a torque on the worm gear.

Preferably, the sensor is embedded in the center of: one of the one or more first bolts and the one or more second bolts; one of the first distal panel and the second distal panel.

Preferably, the slew drive further comprises a control device coupled to the sensor, wherein the control device is configured to receive the signal from the sensor and to perform at least one of storage, analysis and transmission of the signal.

Preferably, the swing driver includes: a first distal plate comprising four first apertures; a second distal plate comprising four second apertures; four first bolts inserted through the four first holes; four second bolts inserted through the four second holes; four sensors, wherein two of the four sensors are coupled with two of the four first bolts and the other two of the four sensors are coupled with two of the four second bolts; and a control device coupled to the four sensors, wherein each of the four sensors is configured to sense a load on each of the two of the four first bolts and the two of the four second bolts in response to a torque on the worm gear and to generate a signal indicative of the torque on the worm gear, wherein the control device is configured to receive the signal from each of the four sensors and to at least one of store, analyze, and transmit the signal.

Preferably, the control apparatus comprises a processor comprising programming code stored on a storage device of the processor and capable of running on the processor, wherein the processor further comprises: an analog-to-digital converter (ADC) for digitizing signals from the sensors at a sampling rate of the ADC and generating digital signals corresponding to each of the four sensors; a communication module for at least one of receiving and transmitting radio waves, wherein the processor is configured to at least one of store, analyze, and transmit at least one of a signal and a digital signal corresponding to each of the four sensors.

Preferably, the processor is configured to construct a histogram of the digital signals corresponding to each of the four sensors.

Preferably, the processor is configured to calculate an average of the digital signals corresponding to each of the four sensors over a predetermined period of time, the average being indicative of an average of the torque on the worm gear.

Preferably, the processor is configured to transmit the average value to the motor controller via the communication module.

Preferably, the processor is configured to calculate a frequency spectrum of the digital signal corresponding to each of the four sensors, the frequency spectrum being indicative of a time varying function of the torque on the worm gear.

Preferably, the processor is configured to transmit the frequency spectrum to the motor controller via the communication module.

Drawings

Fig. 1A shows a left perspective view of the front side of a rotary drive, wherein a first end plate is used to fix the worm on the housing by means of four bolts.

Fig. 1B shows a right perspective view of the front side of the rotary drive with a second end plate for further securing the worm to the housing by four bolts.

Fig. 1C shows a front cross-sectional view of the rotary drive, which shows how the worm and the worm wheel mesh.

Fig. 2A shows a left perspective view of the front side of a swing drive having a first end plate with four bolts. According to a preferred embodiment, one or more sensors may be coupled to the first end plate or the center of the four bolts to measure the torque on the worm gear.

Fig. 2B shows a front cross-sectional view of the rotary drive of fig. 2A, further illustrating how the first end plate, bolts and bearings withstand the torque applied to the external unit, which is manifested as an axial force of the worm.

Fig. 2C shows a perspective view of two of the four bolts in fig. 2A, which may be selected to embed two sensors, such as strain gauges, in the center of the bolts according to a preferred embodiment.

Fig. 3A shows a right perspective view of the front side of the swing drive having a second end plate with four bolts. According to a preferred embodiment, one or more sensors may be coupled to the second end plate or the center of the four bolts to measure the torque on the worm gear.

Fig. 3B shows a front cross-sectional view of the rotary drive of fig. 3A, further showing how the second end plate, bolts and bearings withstand the torque applied to the external unit, which is manifested as axial force of the worm.

FIG. 3C shows a perspective view of two of the four bolts in FIG. 3A, which may be selected to embed two sensors, such as strain gauges, in the center of the bolts according to a preferred embodiment.

FIG. 4 shows a perspective view of two bolts with example holes drilled in the bolts for embedding sensors, according to a preferred embodiment. The torque applied to the external unit may cause an axial load on the bolt and the sensor may generate a signal. According to a preferred embodiment, the schematic in this figure shows a control apparatus comprising a processor, a memory device and an ADC, which can be used to store, analyze and transmit signals.

Fig. 5 shows a schematic diagram of a slew drive equipped with four strain gauges whose signal wires carry strain information and which are coupled with a control device having an I/O port including a communication module to store, analyze and/or transmit strain information from each of the four strain gauges, according to a preferred embodiment.

FIG. 6A shows a perspective cutaway view of an improved integrated slew drive equipped with one or more sensors to measure the torque applied to the worm gear, according to a preferred embodiment.

Fig. 6B shows a front cross-sectional view of the improved integrated rotary drive of fig. 6A equipped with one or more sensors to measure the torque applied to the worm gear, wherein the torque is manifested as an axial force on the worm, the direction of the axial force depending on the direction in which the torque is applied.

Detailed Description

Fig. 1A to 1C show a rotary drive in different views. In particular, fig. 1A shows a left perspective view of the front side of a slew drive with an end plate 104 used to secure a worm 118 to a housing 120 (fig. 1C) using four bolts 102. Fig. 1B shows a right perspective view of the front side of the slew drive with another end plate 108 used to secure the worm 118 to the housing 120 (fig. 1C) using four bolts 106. Fig. 1C is an elevational cross-section of the rotary drive showing how the worm 118 engages the worm gear 116. Two tapered roller bearings 112, 114 are mounted at both ends of a housing 120, and a worm 118 is mounted in the inner race of the bearings 112, 114. The end plates 104, 108 abut the housing 120 and the bearings 112, 114. Bolts 102 (not visible in this cross-sectional view) and 106 serve to secure the worm in an axial direction while imparting an axial compressive force to worm 118 to enhance and improve the meshing between the teeth of worm 118 and worm gear 116. A seal 110 is disposed within the endplate 104 to prevent lubricant from exiting the housing 120.

It is an object of the present invention to measure the torque applied to an external unit (not shown) by embedding one or more sensors in one or more of the end plates 104, 108 and bolts 102, 106. During operation, the torque applied to the external unit is applied equally, but in the opposite direction (known to the skilled person) to the worm wheel. As such, references to torque applied to the external device should be understood to refer to equal but opposite torque applied to the worm gear. This torque is then transmitted to the worm as an axial force through the worm, which is algebraically added to the pulling force in the bolt. The sensor is calibrated to a zero setting in an unloaded state, and due to axial forces during operation, the sensor detects strain in one or more of the end plates 104, 108 and bolts 102, 106 (see fig. 2C or fig. 3C). The monitoring/control device, hereinafter referred to as the control device (see fig. 5), receives signals generated by the sensors, which may be stored, processed/analyzed, and/or transmitted to an external device (not shown) via wired or wireless communication.

Fig. 2A and 2B show how the bolt 106 withstands a torque applied to an external unit (not shown). The torque 204 on the worm gear (fig. 1C, 116) is represented by the axial force 206 through the worm (fig. 1C, 118) and the exemplary reaction forces 208-214, which are further transmitted through the two tapered roller bearings (fig. 1C, 112 and 114), the two end plates (fig. 1C, 104 and 108) and the 8 bolts (fig. 1C, 102 and 106).

Figure 2C shows two bolts 218 and 220, each of which may be used to embed a sensor, in this example a strain gauge 202 available from HBM corporation (marbol butte street 19, massachusetts, zip code 01752). Optical strain gauges may also be used to measure the axial force experienced by bolts 102 and 106.

According to a preferred embodiment, a hole 216 is drilled in the bolt 218 and the strain gauge 202 is inserted into the hole 216. The axial load experienced by the bolt 218 (due to the torque 204) may be measured, stored, processed/analyzed, and transmitted via a control device (see fig. 5) through wired or wireless communication.

Fig. 3A and 3B show how the bolt 102 withstands a torque applied to an external unit (not shown). The torque 304 of the worm gear (fig. 1C, 116) is represented by the axial force 306 through the worm (fig. 1C, 118) and exemplary reaction forces 308-314, which are further transmitted through the two tapered roller bearings (fig. 1C, 112 and 114), the two end plates (fig. 1C, 104 and 108) and the eight bolts (fig. 1C, 102 and 106).

Similar to the configuration described above, a hole 316 is drilled in the bolt 318 and the strain gauge 302 is inserted into the hole 316. The axial load experienced by the bolt 318 (due to the torque 304) may be measured, stored, processed/analyzed, and transmitted via a control device (see fig. 5) through wired or wireless communication. Although only one strain gauge is sufficient to measure the torque 204/304, all 8 bolts 102 and 106 may be used to embed 8 strain gauges to improve measurement accuracy.

Fig. 2B and 3B show torques 204 and 304 applied to the worm gear in two directions. The applied torques 204 and 304 may be static or dynamic, steady state or transient. The signal generated by the strain gauge 202 or 302 is an electrical signal that is digitized, stored, processed/analyzed, and/or transmitted using a control device, which will be discussed in greater detail below.

Fig. 4 shows two bolts 402, 404 and an exemplary hole 412, the hole 412 being drilled in the center of the bolt 404 to embed the strain gauge 410. The torque applied to the external unit causes an axial load in the bolt 404, and the strain gauge 410 generates an electrical signal (hereinafter referred to as signal). The control device 412 includes electronic circuitry 406 for monitoring the strain gauge during operation of the slew drive. The control means 412 includes a processor 408 and also includes a memory device, an analog-to-digital converter (ADC) and a communication module for digitizing, storing, analyzing and transmitting the results. Due to the applied torque, the force on the bolt 402 is converted into a torque being applied to the worm gear and measured, digitized and stored at a high rate and in real time in a memory unit of the control device 412. The stored data may be used to determine various torques that the slew drive is exposed to during operation. A histogram may be derived from the recorded torques to provide information about the operational state of the swing drive over the life, including information of the point of failure and the proximity of the operational specifications. The processor 408 may be configured to construct a histogram of the digital signal. The processor 408 may be configured to average the digital signal over a predetermined period of time, the average being indicative of an average of the torque on the worm gear. The processor 408 may be configured to transmit the average value to the motor controller via the communication module. The processor 408 may be configured to use a fourier transform method (known to those of ordinary skill) to calculate a frequency spectrum of the digital signal that is indicative of a time varying function of the torque on the worm gear. The processor 408 may be configured to transmit the frequency spectrum to the motor controller via the communication module.

Fig. 5 shows a schematic diagram of a rotary drive 502 equipped with 4 strain gauges, whose signal lines 504, 506, 508, 510, 520, 522, 524 and 526 are coupled to a control device 518. According to a preferred embodiment, the control device 518 is a 68HC08 processor with internal flash memory, which is available from ciscarl (austin, tx). It is contemplated that the processor may be a combination of separate discrete or discrete integrated circuits enclosed in a single housing, or it may be fabricated in a single integrated circuit. The control 518 includes an analog to digital converter that digitizes the strain gauge signal for storage and further processing including digital signal processing. Unprocessed or processed data may be transmitted over communications port 512 to communications network 514 via radio waves 516, which radio waves 516 include bluetooth and/or WiFi. Data may also be transmitted via a wired communication line (not shown). In this manner, the operation of the slew drive 502 may be monitored and controlled in real time.

Control 518 is used to determine the torque of the swing drive at a high rate at any time during its operation. This can be used to determine the dynamic and static conditions/exposure of the drive in an application (e.g. dynamic wind swings in solar tracker applications), the proximity of the drive to a point of failure, the proximity of the drive to absolute specification (absolute specification).

Torque sensing in the drive can also be used as feedback in a control loop to direct the drive of the drive to achieve a desired static or dynamic result. For example, if the drive torque is approaching the limit capacity of the drive, the sensor may direct the motor controller to move the drive in the direction of the release torque. In another example, if a driver in a solar tracker experiences vibration from a wind drive, the torque of the vibration may be used to instruct the solar tracker to drive the driver in a manner that mitigates dynamic wind effects/motion.

Fig. 6A and 6B illustrate in different views a modified integrated slew drive, also disclosed in co-owned pending patent application No.16133375, which is incorporated herein by reference in its entirety. In particular, fig. 6A shows a perspective cutaway view of a slew drive. The rotary drive includes a housing 602, the housing 602 including a first distal housing portion having a threaded portion. The housing 602 also includes a second distal housing portion having a recess. The first distal housing part accommodates a threaded plug 614, which threaded plug 614 is screwed into the threaded part. A groove is machined in the second distal housing part to accommodate a retaining ring 608, such as a spring clip.

Fig. 6B shows a front sectional view of the swing driver. The worm 606 is secured to the rotary drive housing 602 by a first tapered roller bearing 612 and a second tapered roller bearing 610. The worm 606 includes a central threaded portion, a first distal shaft portion having a first shoulder, and a second distal shaft portion having a second shoulder. The central threaded portion of the worm 606 meshes with the worm gear teeth of the worm wheel 604. The worm 606 rotates about its axial axis and causes the worm wheel 604 to rotate about its axial axis.

A first tapered roller bearing 612 is disposed on the first distal shaft portion adjacent the first shoulder and threaded plug 614 and a second tapered roller bearing 610 is disposed on the second distal shaft portion adjacent the second shoulder and retaining ring 608. A seal 618, such as grease, is disposed on the second distal shaft portion, abutting the retaining ring 608 to prevent lubricant from exiting the housing 602.

When the rotating threaded plug 614 is engaged with the threaded portion of the first distal housing portion of the housing 602, an axial compressive force is exerted on the worm 606 by the first tapered roller 612 to ensure improved engagement between the threaded portion of the worm 606 and the worm gear teeth of the worm wheel 604. The retaining ring 608 applies a force of the same magnitude, but opposite direction, to the worm 606 through the second tapered roller bearing 610.

Fig. 6A and 6B illustrate how the plug 614 and the retaining ring 608 withstand the torque applied to the external unit (not shown). The torque of the worm wheel 604, depending on the direction of the applied torque, is represented as an axial force 620 or 622 through the worm 606, which is further transmitted through the two tapered roller bearings 612, 610, the threaded plug 614 and the retaining ring 608.

Similar to the configuration described above, the strain gauge 616 may be inserted into the center of the plug 614 or the retaining ring 608. The axial load (due to torque) experienced by the plug 614 or the retaining ring 608 may be measured, stored, processed and transmitted by wired or wireless control means as described above (see fig. 5).

The foregoing explanations, descriptions, illustrations, examples, and discussions have been set forth to aid the reader in understanding the present invention and to further demonstrate the utility and novelty, and are not intended to limit the scope of the present invention in any limiting manner. The following claims, including all equivalents, are intended to define the scope of the invention.