AU2018100052A4 - A Torque Measuring Apparatus - Google Patents

Abstract

Abstract The present invention relates to a torque measuring apparatus for a planetary drive. The apparatus includes a torque measuring mechanism, an input gearbox housing and an output gearbox housing. The torque 5 measuring mechanism is located between and operably connected to input and output stages of a gearbox adapted to be driven by a torque load. The input gearbox housing accommodates an input stage structure which generates a reaction torque in response to the torque load. The output gearbox housing accommodates an output stage structure to which the 10 reaction torque is transmitted via the torque measuring mechanism which is adapted to transform the reaction torque into a measurable linear force. The input gearbox housing is connected to and supported by at least part of the torque measuring mechanism thereby being independent of the input stage structure. 4 CZ)

Description

A Torque Measuring Apparatus

Technical Field

The present invention broadly relates to a torque measuring apparatus. In particular, the present invention relates to a torque measuring apparatus for load monitoring and controlling in planetary drives.

Background of the Invention

Planetary gearing, with its inherent in-line shafting and cylindrical casing, is often recognized as the compact alternative to standard pinion-and-gear reducers. Being suited for a wide range of applications - from electric screwdrivers to bulldozer power trains - these units are strong contenders when space and weight versus reduction and torque are chief concerns. Their planetary drive train makes them the ideal choice for all heavy duty applications. A typical application is a thickener drive for wet mineral processing where rakes of the thickener is driven by the drive shaft. As the shaft turns the rakes will sweep the entire bed of the thickener thereby applying torque. The sweeping causes the concentrate that has settled onto the bottom of the thickener to be pulled into a discharge chamber at the centre of the thickener which is generally referred to as the 'cone'. It is from this cone that the thickener underflow is taken.

Conventional high ratio, low output speed planetary drives have an 'intermediate flange' involving two separate gearbox shafts mounted with torque arms between them. The torque generated by the gearboxes are closely monitored by load cells which are associated with limit switches adapted to trigger an alarm if and when there is an over torque. Such a traditional design, as illustrated in Figure 1 as prior art, requires an input gearbox drive a male input shaft on the output gearbox. The alignment of these shafts and connections is critical to ensure that the drive runs smoothly with no oscillation. However, this is a mission impossible as there are always some site conditions and movement in the alignment of the input gearbox which cause oscillation. The traditional design therefore has a shortcoming that a slight wobble is often observed when the planetary drive is in operation. The wobble is believed to be caused by tolerances for the machined parts and the rotating gear train within the housing. The wobble is particularly significant and noticeable with the longer input gearboxes and motor combination.

It is an object of the present invention to provide a torque measuring mechanism which may overcome or at least ameliorate the above shortcoming or which will at least provide a useful alternative.

Summary of the Invention

According to the present invention, there is provided a torque measuring apparatus for a planetary drive, the apparatus including: a torque measuring mechanism being located between and operably connected to input and output stages of a gearbox adapted to be driven by a torque load, an input gearbox housing accommodating an input stage structure which generates a reaction torque in response to the torque load; and an output gearbox housing accommodating an output stage structure to which the reaction torque is transmitted via the torque measuring mechanism which is adapted to transform the reaction torque into a measurable linear force; wherein the input gearbox housing is connected to and supported by at least part of the torque measuring mechanism thereby being independent of the input stage structure.

Preferably, the input stage structure includes selected elements of a planetary gearset. More preferably, the output stage structure includes further elements of the planetary gearset.

Preferably, the input stage structure is connected to the output stage structure via shafting means. More preferably, the shafting means include a splined shaft which is adapted to engage the input stage structure and a splined sleeve which is affixed to the output stage structure.

In a preferred embodiment, the torque measuring mechanism includes: a first member being connected to the input gearbox housing and having a first collar and a first arm; a second member being connected to the output gearbox housing and having a second collar and a second arm; a bearing means intermediate the first and second collars which are adapted to movably engage one another; and a load measuring means having one end joined to the first arm and another end joined to the second arm; wherein the bearing means is capable of facilitating rotation of the first member relative to the second member whilst providing support to the input stage structure.

In a preferred embodiment, the first and second members are concentric. The first member may rotate about a central axis of the second member whilst the second member remains stationary.

Preferably, the first member is in the form of a spindle. More preferably, the spindle is configured to provide both axial and radial support to the input stage structure. Even more preferably, the second member is in the form of a hub.

Preferably, the first and second collars extend in opposite directions confining the bearing means in a secured position.

In operation, the reaction torque applied between the input and out stage structures causes the first and second arms to generate the linear force measurable by the loading measuring means.

Preferably, the load measuring means is a load cell capable of providing a reading which enables calculation of the magnitude of the applied torque.

Preferably, the torque measuring mechanism includes an oil seal located between the first and second members. As such, oil may be supplied by the oil seal to both the input and output stage structures. The oil seal functions as a barrier which retains the lubricating oil where it is bound to be, prevents the oil from leaking outside even under high pressure of the oil and prevents contamination of the oil by external entities.

Preferably, the second member includes internal drainage holes adapted to prevent trapped air pockets during oil filling in a vertical configuration thereby ensuring adequate lubrication of the bearing means.

Brief Description of the Drawings

The invention may be better understood from the following non-limiting description of the preferred embodiment, in which:

Figure 1 is a perspective view of a planetary drive having a prior art torque measuring apparatus involving two separate gearbox shafts mounted with torque arms between them;

Figure 2 is a perspective view of a torque measuring apparatus of the present invention;

Figure 3 is an exploded cross sectional view of the torque measuring apparatus of Figure 2;

Figure 4 is an assembled cross sectional view of the torque measuring apparatus of Figure 2;

Figure 5 is a cross sectional view of the torque measuring mechanism of the torque measuring apparatus of Figure 2;

Figure 6 is a perspective view of a load measuring means of the torque measuring mechanism of Figure 5;

Figure 7 is a perspective view of the torque measuring apparatus of Figure 2 in operation; and

Figure 8 is a cross sectional view illustrating the interior of the torque measuring apparatus in operation.

Detailed Description of the Drawings

Referring to Figures 1 and 2, a torque measuring apparatus 10 for a planetary drive is shown. The torque measuring apparatus 10 has a torque measuring mechanism 12, an input gearbox housing 14 and an output gearbox housing 16. The torque measuring mechanism 12 is located between and operably connected to input and output stages of a gearbox adapted to be driven by a torque load.

As shown in Figures 2 and 3, the input gearbox housing 14 accommodates an input stage structure 18 which generates a reaction torque in response to the torque load. The output gearbox housing 16 accommodates an output stage structure 20 to which the reaction torque is transmitted via the torque measuring mechanism 12 which is adapted to transform the reaction torque into a measurable linear force. The input gearbox housing 14 is connected to and supported by at least part of the torque measuring mechanism thereby being independent of the input stage structure 18. As such, during operation, the movement in and of the input stage structure 18 with rotating drive train components does not impact on the input gearbox housing 14.

As best shown in Figure 2, the input stage structure 18 has selected elements 22 of a planetary gearset. The output stage structure 20 has further elements 24 of the planetary gearset. The input stage structure 18 is connected to the output stage structure 20 via shafting means 26.

In this embodiment, the shafting means 26 has a splined shaft 28 which engages the input stage structure 18 and a splined sleeve 30 which is affixed to the output stage structure 20.

Turning now to Figures 4 and 5, the torque measuring mechanism 12 has a first member in the form of a spindle 34, a second member in the form of a hub 32, a bearing means 36 and a load measuring means 38. The spindle 34 has an upper portion 40 which takes the form of a tub defined by a circumferential flange 42 which is in contact with the input gearbox housing 14. The spindle 34 also has a downwardly extending collar 44 and an arm 46. The hub 32 is secured to the output gearbox housing 16 via fastening means in the form of bolts 48. The hub 32 has an upwardly extending collar 50 and an arm 52. The collars 44 & 50 extend in opposite directions thereby confining the bearing means 36 in a secured position. The bearing means 36 intermediates the collars 44 & 50 which in operation are adapted to movably engage one another. The bearing means 36 is a double row angular contact ball bearing which is capable of facilitating rotation of the spindle 34 relative to the hub 32 whilst providing both axial and radial support to the input stage structure 18. The spindle 34 and hub 32 are concentric functioning as a couple. The spindle 34 is capable of rotating about a central axis of the hub 32 whilst the hub 32 remains stationary.

Referring to Figures 5, 6 and 7, the load measuring means 38 having one end 54 joined to the arm 46 and another end 56 joined to the arm 52. In operation, the reaction torque applied between the input and out stage structures 18 & 20 causes the arms 46 & 52 to generate the linear force measurable by the loading measuring means 38. The load measuring means 38 is a load cell 58 capable of providing a reading which enables calculation of the magnitude of the applied torque. The load measuring means 38 is capable of measuring torque in both directions and the override switch 62 (see Figures 4 and 6) also operates in both directions. The override switch is adjustable via springs changes.

As best shown in Figure 5, the torque measuring mechanism 12 also has an oil seal 60 located between the spindle 34 and hub 32. As such, oil is supplied by the oil seal 60 to both the input and output stage structures 18 & 20. This offers the advantage of requiring on one oil reservoir providing common oil in the gearbox. The oil seal 60 functions as a barrier which retains the lubricating oil where it is bound to be, prevents the oil from leaking outside even under high pressure and prevents contamination of the oil by external entities. The hub 32 also has internal drainage holes (not shown) which prevent trapped air pockets during oil filling in a vertical configuration thereby ensuring adequate lubrication of the bearing means 36.

Referring to Figure 8, the torque measuring apparatus 10 is shown with the gearboxes being physically connected through the collars 44 & 50 which are in the shape of flanges via the bearing means 36. As the drive is connected internally, no oscillation is observed or detected during load testing.

Now that a preferred embodiment of the present invention has been described in some detail, it will be apparent to a skilled person in the art that the torque measuring apparatus of the present invention may offer at least the following advantages: 1. it enables the input gearbox housing toe be supported independently of the rotating drive train components thereby eliminating any wobble or oscillation; and 2. it enables the drive unit to have a single oil level monitoring point as a result of the oil seal between the spindle and the hub allowing the upper and lower gearboxes to share oil.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. All such variations and modifications are to be considered within the scope and spirit of the present invention the nature of which is to be determined from the foregoing description.

Claims (14)

1. Claims

   1. A torque measuring apparatus for a planetary drive, the apparatus including: a torque measuring mechanism being located between and operably connected to input and output stages of a gearbox adapted to be driven by a torque load, an input gearbox housing accommodating an input stage structure which generates a reaction torque in response to the torque load; and an output gearbox housing accommodating an output stage structure to which the reaction torque is transmitted via the torque measuring mechanism which is adapted to transform the reaction torque into a measurable linear force; wherein the input gearbox housing is connected to and supported by at least part of the torque measuring mechanism thereby being independent of the input stage structure.
2. 2. The torque measuring apparatus of claim 1, wherein the input stage structure includes selected elements of a planetary gearset.
3. 3. The torque measuring apparatus of either claim 1 or 2, wherein the output stage structure includes further elements of the planetary gearset.
4. 4. The torque measuring apparatus of any one of the preceding claims, wherein the input stage structure is connected to the output stage structure via shafting means.
5. 5. The torque measuring apparatus of claim 4, wherein the shafting means include a splined shaft which is adapted to engage the input stage structure and a splined sleeve which is affixed to the output stage structure.
6. 6. The torque measuring apparatus of any one of the preceding claims, wherein the torque measuring mechanism includes: a first member being connected to the input gearbox housing and having a first collar and a first arm; a second member being connected to the output gearbox housing and having a second collar and a second arm; a bearing means intermediate the first and second collars which are adapted to movably engage one another; and a load measuring means having one end joined to the first arm and another end joined to the second arm; wherein the bearing means is capable of facilitating rotation of the first member relative to the second member whilst providing support to the input stage structure.
7. 7. The torque measuring apparatus of claim 6, wherein the first and second members are concentric.
8. 8. The torque measuring apparatus of either claim 6 or 7, wherein the first member rotates about a central axis of the second member whilst the second member remains stationary.
9. 9. The torque measuring apparatus of any one of claims 6 to 8, wherein the first member is in the form of a spindle.
10. 10. The torque measuring apparatus of claim 9, wherein the spindle is configured to provide both axial and radial support to the input stage structure.
11. 11. The torque measuring apparatus of any one of claims 6 to 10, wherein the second member is in the form of a hub.
12. 12. The torque measuring apparatus of any one of claims 6 to 11, wherein the first and second collars extend in opposite directions confining the bearing means in a secured position.
13. 13. The torque measuring apparatus of any one of claims 6 to 12, wherein the torque measuring mechanism includes an oil seal located between the first and second members.
14. 14. The torque measuring apparatus of claim 11, wherein the hub includes internal drainage holes adapted to prevent trapped air pockets during oil filling in a vertical configuration thereby ensuring adequate lubrication of the bearing means.