TRANSMISSION SYSTEM FOR DRILLING MACHINE

Abstract

A transmission system for a drilling machine includes a drive pump, a motor driven by the drive pump, a first fluid line that fluidly couples the motor with the drive pump, and a second fluid line that fluidly couples the motor with the drive pump. The transmission system also includes a charge pump in fluid communication with the drive pump, a fluid charge line that fluidly couples the charge pump with the drive pump, and an accumulator disposed in the fluid charge line. In an event of a change in a load on the transmission system, the accumulator is adapted to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor.

Description

TECHNICAL FIELD

The present disclosure relates to a drilling machine, a transmission system for the drilling machine, and a method of operating the transmission system of the drilling machine.

BACKGROUND

Drilling machines include a mast that is movably coupled to a frame of the drilling machine. The mast supports one or more drilling components, for example, a drill bit, a hammer, a drill pipe, and the like, to perform drilling operations.

Such drilling machines include a closed-circuit hydrostatic transmission system that operates the one or more drilling components. The hydrostatic transmission system includes one or more drive pumps that are operated by a power source of the drilling machine. The hydrostatic transmission system also includes one or more motors driven by pressure generated by the drive pump and supplied by fluid lines connected between the drive pump and the motor. The motor in turn operates the drilling components. The hydrostatic transmission system further includes a charge circuit. The charge circuit includes a charge pump that replenishes fluid losses occurring in the hydrostatic transmission system, supplies lubrication and cooling flow to one or more components of the hydrostatic transmission system, and also supports pilot pressure for control systems associated with the hydrostatic transmission system. A sudden change in load or torque during an operational event can cause high fluctuations at a low pressure side of the hydrostatic transmission system. Due to such events, a low pressure may be experienced in one of the fluid lines that fluidly connect the drive pump and the motor. Such operational events may include, for example, a break-out event or a tightening event of one or more drill pipes of the drilling machine, a change in a speed of a drill bit, and the like.

In some cases, the pressure at the low pressure side of the hydrostatic transmission system may decrease to as low as 0 bar, which may have a detrimental effect on the drive pump or other components of the hydrostatic transmission system. In some examples, such low pressures may reduce a service life of the components of the hydrostatic transmission system or may cause failure of such components. A size of the charge pump that is currently deployed in the hydrostatic transmission system may not be sufficient to prevent a pressure drop in the low pressure side. Further, increasing a size of the charge pump to overcome the pressure drop may not be feasible. Thus, it is desirable to employ a means of limiting the pressure drop in the fluid lines to ensure continued working of the transmission system and to prevent component failure.

DE4000185A1 describes a hydrostatic gear has a closed circuit and a drive pump with variable displacement, whereby a motor is connected by a first hydraulic lead and a second hydraulic lead to the drive pump. A pressure accumulator is attached by a first non-return valve to the second hydraulic lead by the second non-return valve.

SUMMARY OF THE DISCLOSURE

In an aspect of the present disclosure, a transmission system for a drilling machine is provided. The transmission system includes a drive pump. The transmission system also includes a motor driven by the drive pump. The transmission system further includes a first fluid line that fluidly couples the motor with the drive pump. The transmission system includes a second fluid line that fluidly couples the motor with the drive pump. The transmission system also includes a charge pump in fluid communication with the drive pump. The transmission system further includes a fluid charge line that fluidly couples the charge pump with the drive pump. The transmission system includes an accumulator disposed in the fluid charge line and in selective fluid communication with the first fluid line and the second fluid line. In an event of a change in a load on the transmission system, the accumulator is adapted to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor.

In another aspect of the present disclosure, a drilling machine is provided. The drilling machine includes a frame. The drilling machine also includes at least one drilling component. The drilling machine further includes a transmission system operatively coupled with the at least one drilling component. The transmission system includes a drive pump. The transmission system also includes a motor driven by the drive pump and adapted to operate the at least one drilling component of the drilling machine. The transmission system further includes a first fluid line that fluidly couples the motor with the drive pump. The transmission system includes a second fluid line that fluidly couples the motor with the drive pump. The transmission system also includes a charge pump in fluid communication with the drive pump. The transmission system further includes a fluid charge line that fluidly couples the charge pump with the drive pump. The transmission system includes an accumulator disposed in the fluid charge line and in selective fluid communication with the first fluid line and the second fluid line. In an event of a change in a load on the transmission system, the accumulator is adapted to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor.

In yet another aspect of the present disclosure, a method of operating a transmission system of a drilling machine is provided. The method includes operating a drive pump of the transmission system. The transmission system further includes a charge pump and a fluid charge line that are in fluid communication with the drive pump. The method also includes operating a motor of the transmission system based on operation of the drive pump. The transmission system further includes a first fluid line that fluidly couples the motor with the drive pump and a second fluid line that fluidly couples the motor with the drive pump. The method further includes operating an accumulator of the transmission system to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor in an event of a change in a load on the transmission system. The accumulator is disposed in the fluid charge line and in selective fluid communication with the first fluid line and the second fluid line.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of an exemplary drilling machine;

FIG. 2 is a schematic diagram of a transmission system of the drilling machine of FIG. 1, according to an example of the present disclosure; and

FIG. 3 is a flowchart for a method of operating the transmission system of the drilling machine, according to an example of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts.

Referring to FIG. 1, a schematic side view of an exemplary drilling machine 100 is illustrated. The drilling machine 100 may be used to perform one or more drilling operations, such as, surface drilling, drilling holes, mining blast holes, geothermal wells, and the like. The drilling machine 100 may include a rotary drilling machine or a down-the-hole drilling machine. In the illustrated example of FIG. 1, the drilling machine 100 is embodied as the rotary drilling machine. The drilling machine 100 may include a surface rock drill. The drilling machine 100 defines a first axis “F1”. The first axis “F1” extends generally in a vertical direction.

As shown in FIG. 1, the drilling machine 100 includes a frame 102. The frame 102 may be supported on a ground surface by a transport mechanism, such as, crawler tracks 104. The crawler tracks 104 may allow the drilling machine 100 to maneuver on ground surfaces to a desired location for performing drilling operations. Alternatively, the drilling machine 100 may include wheels instead of the crawler tracks 104. The frame 102 includes one or more jacks (not shown herein) for supporting and leveling the drilling machine 100 on the ground surface during drilling operations. In an example, the one or more jacks may lift the drilling machine 100 above the ground surface along the first axis “F1” during drilling operations.

The drilling machine 100 also includes a machinery 108. The frame 102 may support the machinery 108, which may include various components (not shown), such as, a power source 116 (shown in FIG. 2). The power source 116 may include, for example, an engine, a battery system, and/or a fuel cell, that supplies power to operate the drilling machine 100. The frame 102 further supports an operator cabin 110, from which an operator may maneuver and control the drilling machine 100.

The drilling machine 100 includes a mast assembly 112. The mast assembly 112 may be supported by the frame 102 of the drilling machine 100. The mast assembly 112 extends along the first axis “F1”. The drilling machine 100 also includes a mast 113 coupled to the frame 102 that is movable relative to the frame 102. Specifically, the mast assembly 112 includes the mast 113.

The drilling machine 100 further includes a drill head 114 movable relative to the mast assembly 112. The drill head 114 is movable along the first axis “F1” and supported on the mast 113. The drilling machine 100 includes one or more drilling components 118 (schematically shown in FIG. 2). The one or more drilling components 118 include a drill pipe, a drill bit, or a hammer, without any limitations. The one or more drilling components 118 may be coupled to the drill head 114 to perform drilling operations.

As shown in FIG. 2, the drilling machine 100 includes a transmission system 200. The transmission system 200 is embodied as a closed-circuit hydrostatic transmission system. The transmission system 200 is operatively coupled with the one or more drilling components 118. The transmission system 200 includes a drive pump 202. The drive pump 202 includes a bi-directional pump. The drive pump 202 is a variable displacement hydraulic pump. The drive pump 202 is driven by the power source 116 of the drilling machine 100. The drive pump 202 includes a first port 204 and a second port 206. The drive pump 202 may be controlled, via a flow control valve (not shown herein), to vary a speed of the drive pump 202.

The transmission system 200 also includes a motor 208 driven by the drive pump 202. The motor 208 operates the one or more drilling components 118 of the drilling machine 100. The motor 208 is a variable displacement motor. The motor 208 includes a bi-directional motor that can rotate in a clockwise direction and a counter-clockwise direction. The motor 208 includes a first port 210 and a second port 212.

The transmission system 200 further includes a first fluid line 214 that fluidly couples the motor 208 with the drive pump 202. The first fluid line 214 provides fluid communication between the first port 204 of the drive pump 202 and the first port 210 of the motor 208 to rotate the motor 208 in the counter-clockwise direction. The first port 204 of the drive pump 202 fluidly communicates with the first port 210 of the motor 208 via the first fluid line 214.

The transmission system 200 also includes a second fluid line 216 that fluidly couples the motor 208 with the drive pump 202. The second fluid line 216 provides fluid communication between the second port 206 of the drive pump 202 and the second port 212 of the motor 208 to rotate the motor 208 in the clockwise direction. Further, the second port 206 of the drive pump 202 fluidly communicates with the second port 212 of the motor 208 via the second fluid line 216. The drive pump 202, the motor 208, the first fluid line 214, and the second fluid line 216 together form a main circuit of the transmission system 200.

The transmission system 200 also includes a charge pump 218 in fluid communication with the drive pump 202. The charge pump 218 supplies fluid to the drive pump 202. The fluid may be oil, or any other hydraulic fluid. The charge pump 218 is operated by the power source 116. The charge pump 218 may include a constant displacement pump that operates in a single direction. The charge pump 218 may replenish fluid losses happening within the transmission system 200 due to internal leakage of rotary components of the transmission system 200, supply lubrication and cooling flow to the main circuit of the transmission system 200, and supports pilot pressure for control systems associated with the transmission system 200. The transmission system 200 further includes a fluid charge line 220 that fluidly couples the charge pump 218 with the drive pump 202.

The transmission system 200 further includes a first supply line 222 that provides fluid communication between the first fluid line 214 and the fluid charge line 220. The transmission system 200 further includes a first valve 224. The first valve 224 is disposed upstream of the drive pump 202 and provides fluid communication between the fluid charge line 220 and the drive pump 202. The first valve 224 is disposed in the first supply line 222. The first valve 224 allows selective fluid flow from the fluid charge line 220 towards the first fluid line 214 via the first supply line 222. Further, the first valve 224 prevents return flow from the first fluid line 214 towards the fluid charge line 220. The first valve 224 may include a check valve.

The transmission system 200 further includes a second supply line 226 that provides fluid communication between the second fluid line 216 and the fluid charge line 220. The transmission system 200 further includes a second valve 228. The second valve 228 is disposed upstream of the drive pump 202 and provides fluid communication between the fluid charge line 220 and the drive pump 202. The second valve 228 is disposed in the second supply line 226. The second valve 228 allows selective fluid flow from the fluid charge line 220 towards the second fluid line 216. Further, the second valve 228 prevents return flow from the second fluid line 216 towards the fluid charge line 220. The second valve 228 may include a check valve.

Thus, the fluid charge line 220 is in fluid communication with each of the first supply line 222 and the second supply line 226. When a pressure in the fluid charge line 220 is greater than a pressure in the first or second supply lines 222, 226, the fluid can flow through one of the first and second supply lines 222, 226, via the respective first or second valves 224, 228. The charge pump 218, the fluid charge line 220, the first supply line 222, and the second supply line 226 together form a charge circuit.

The transmission system 200 further includes an accumulator 230 disposed in the fluid charge line 220 and in selective fluid communication with the first fluid line 214 and the second fluid line 216. The accumulator 230 may include a bladder accumulator, a piston accumulator, or a diaphragm accumulator. In an example, the accumulator 230 is disposed proximal to the first and second valves 224, 228. The accumulator 230 is in fluid communication with the fluid charge line 220 via a fluid line 232.

In an event of a change in a load on the transmission system 200, the accumulator 230 supplies additional fluid towards the first fluid line 214 or the second fluid line 216 to prevent a reduction in a pressure in the first fluid line 214 or the second fluid line 216 below a recommended operating level of the drive pump 202 or the motor 208. In some examples, upon the supply of the additional fluid by the accumulator 230, the pressure in the first fluid line 214 or the second fluid line 216 is at least equal to a charge pressure in the fluid charge line 220. In an example, upon the supply of the additional fluid by the accumulator 230, the pressure in the first fluid line 214 or the second fluid line 216 may be equal to a charge pressure at an outlet of the charge pump 218. In some examples, the recommended operating level may lie between 5 bar and 22 bar. In some examples, the accumulator 230 supplies the additional fluid during one or more operational events, such as, a break-out event, a tightening or loosening event of one or more drill pipes of the drilling machine 100 (see FIG. 1), a change in a speed of a drill bit, and the like, without any limitations. The break-out event may include an event in which the drill bit is stuck, and a rotation of the drill bit has stopped but the torque is high, and the drill bit breaks loose causing a whipping action.

In an example, when the motor 208 is rotating in the counter-clockwise direction, the drive pump 202 supplies pressurized fluid from the first port 204 of the drive pump 202 to the first port 210 of the motor 208 via the first fluid line 214. In such an example, the first fluid line 214 is a high pressure line. Further, fluid returns from the second port 206 of the drive pump 202 to the second port 212 of the motor 208 via the second fluid line 216. In such an example, the second fluid line 216 is a low pressure line.

During one or more operational events, if the pressure in the second fluid line 216 reduces significantly, the accumulator 230 supplies the additional fluid to the second fluid line 216 to prevent the pressure in the second fluid line 216 to reduce below the recommended operating level. Specifically, during a rapid pressure drop in the second fluid line 216, the second valve 228 may open and fluid is transferred from the accumulator 230 into the second fluid line 216, via the second supply line 226 and the second valve 228, thereby preventing a pressure drop in the second fluid line 216.

In another example, when the motor 208 is rotating in the clockwise direction, the drive pump 202 supplies pressurized fluid from the second port 206 of the drive pump 202 to the second port 212 of the motor 208 via the second fluid line 216. In such an example, the second fluid line 216 is a high pressure line. Further, fluid returns from the first port 204 of the drive pump 202 to the first port 210 of the motor 208 via the first fluid line 214. In such an example, the first fluid line 214 is a low pressure line.

During one or more operational events, if the pressure in the first fluid line 214 reduces significantly, the accumulator 230 supplies the additional fluid to the first fluid line 214 to prevent the pressure in the first fluid line 214 to reduce below the recommended operating level. Specifically, during a rapid pressure drop in the first fluid line 214, the first valve 224 may open and fluid is transferred from the accumulator 230 into the first fluid line 214, via the first supply line 222 and the first valve 224, thereby preventing a pressure drop in the first fluid line 214.

It should be noted that the transmission system 200 may further include other components that are not illustrated and explained in this disclosure, for the sake of simplicity. Such components may assist the transmission system 200 in performing the intended functions in a manner known in the art, as per application requirements.

It is to be understood that individual features shown or described for one embodiment may be combined with individual features shown or described for another embodiment. The above-described implementation does not in any way limit the scope of the present disclosure. Therefore, it is to be understood although some features are shown or described to illustrate the use of the present disclosure in the context of functional segments, such features may be omitted from the scope of the present disclosure without departing from the spirit of the present disclosure as defined in the appended claims.

INDUSTRIAL APPLICABILITY

The present disclosure relates to the transmission system 200 including the accumulator 230. When the pressure in the first or second fluid lines 214, 216 reduces due to one or more operational events in the drilling machine 100, the accumulator 230 supplies the additional fluid to the first or second fluid lines 214, 216, thereby preventing the pressure in the first or second fluid lines 214, 216 to reduce below the recommended operating level of the drive pump 202 or the motor 208. Such operational events may include, for example, the break-out event or the tightening event of the one or more drill pipes of the drilling machine 100, the change in the speed of the drill bit, and the like.

The accumulator 230 may improve an overall performance and a reliability of the transmission system 200. The accumulator 230 presents a simple and a cost-effective technique of maintaining the pressure in the low pressure line within acceptable limits. As the pressure in the low pressure line is prevented from reducing below the recommended operating level of the drive pump 202 or the motor 208, a susceptibility of failure of the drive pump 202, the motor 208, or other components of the transmission system 200 may be prevented. Thus, the accumulator 230 may prevent a reduction in a service life of the components of the transmission system 200, and may also reduce cost and efforts associated with replacement or servicing of the components of the transmission system 200. Further, the teachings of the present disclosure may be implemented on existing drilling machines.

FIG. 3 illustrates a flowchart for a method 300 of operating the transmission system 200 of the drilling machine 100. Referring to FIGS. 1 to 3, at step 302, the drive pump 202 of the transmission system 200 is operated. The transmission system 200 further includes the charge pump 218 and the fluid charge line 220 that are in fluid communication with the drive pump 202. The drive pump 202 includes the bi-directional pump. The step 302 further includes operating the drive pump 202 in any one of the clockwise direction and the counter-clockwise direction.

At step 304, the motor 208 of the transmission system 200 is operated based on the operation of the drive pump 202. The transmission system 200 further includes the first fluid line 214 that fluidly couples the motor 208 with the drive pump 202 and the second fluid line 216 that fluidly couples the motor 208 with the drive pump 202

At step 306, the accumulator 230 of the transmission system 200 is operated to supply the additional fluid towards the first fluid line 214 or the second fluid line 216 to prevent the reduction in the pressure in the first fluid line 214 or the second fluid line 216 below the recommended operating level of the drive pump 202 or the motor 208 in the event of the change in the load on the transmission system 200. The accumulator 230 is disposed in the fluid charge line 220 and in selective fluid communication with the first fluid line 214 and the second fluid line 216. Further, upon the supply of the additional fluid by the accumulator 230, the pressure in the first fluid line 214 or the second fluid line 216 is at least equal to the charge pressure in the fluid charge line 220.

The method 300 further includes a step of at which the motor 208 operates the one or more drilling components 118 of the drilling machine 100 based on the operation of the motor 208. The one or more drilling components 118 includes the drill pipe, the drill bit, or the hammer.

It should be noted that one or more steps 302, 304, 306 of the method 300 may be performed in an order that is different from that explained and illustrated in reference to FIG. 3. Further, one or more of the steps 302, 304, 306 may be performed together.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

1. A transmission system for a drilling machine, the transmission system comprising:

a drive pump;

a motor driven by the drive pump;

a first fluid line that fluidly couples the motor with the drive pump;

a second fluid line that fluidly couples the motor with the drive pump;

a charge pump in fluid communication with the drive pump;

a fluid charge line that fluidly couples the charge pump with the drive pump; and

an accumulator disposed in the fluid charge line and in selective fluid communication with the first fluid line and the second fluid line, wherein, in an event of a change in a load on the transmission system, the accumulator is adapted to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor.

2. The transmission system of claim 1 further comprising a first valve disposed upstream of the drive pump and adapted to provide fluid communication between the fluid charge line and the drive pump.

3. The transmission system of claim 2 further comprising a first supply line that provides fluid communication between the first fluid line and the fluid charge line, wherein the first valve is disposed in the first supply line, and wherein the first valve allows selective fluid flow from the fluid charge line towards the first fluid line via the first supply line.

4. The transmission system of claim 1 further comprising a second valve disposed upstream of the drive pump and adapted to provide fluid communication between the fluid charge line and the drive pump.

5. The transmission system of claim 4 further comprising a second supply line that provides fluid communication between the second fluid line and the fluid charge line, wherein the second valve is disposed in the second supply line, and wherein the second valve allows selective fluid flow from the fluid charge line towards the second fluid line via the second supply line.

6. The transmission system of claim 1, wherein, upon the supply of the additional fluid by the accumulator, the pressure in at least one of the first fluid line and the second fluid line is at least equal to a charge pressure in the fluid charge line.

7. The transmission system of claim 1, wherein the drive pump includes a bi-directional pump.

8. The transmission system of claim 1, wherein the motor is adapted to operate at least one drilling component of the drilling machine.

9. The transmission system of claim 8, wherein the at least one drilling component includes a drill pipe, a drill bit, or a hammer.

10. A drilling machine comprising:

a frame;

at least one drilling component; and

a transmission system operatively coupled with the at least one drilling component, the transmission system including: a drive pump; a motor driven by the drive pump and adapted to operate the at least one drilling component of the drilling machine; a first fluid line that fluidly couples the motor with the drive pump; a second fluid line that fluidly couples the motor with the drive pump; a charge pump in fluid communication with the drive pump; a fluid charge line that fluidly couples the charge pump with the drive pump; and an accumulator disposed in the fluid charge line and in selective fluid communication with the first fluid line and the second fluid line, wherein, in an event of a change in a load on the transmission system, the accumulator is adapted to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor.

11. The drilling machine of claim 10 further comprising a first valve disposed upstream of the drive pump and adapted to provide fluid communication between the fluid charge line and the drive pump.

12. The drilling machine of claim 11 further comprising a first supply line that provides fluid communication between the first fluid line and the fluid charge line, wherein the first valve is disposed in the first supply line, and wherein the first valve allows selective fluid flow from the fluid charge line towards the first fluid line via the first supply line.

13. The drilling machine of claim 10 further comprising a second valve disposed upstream of the drive pump and adapted to provide fluid communication between the fluid charge line and the drive pump.

14. The drilling machine of claim 13 further comprising a second supply line that provides fluid communication between the second fluid line and the fluid charge line, wherein the second valve is disposed in the second supply line, and wherein the second valve allows selective fluid flow from the fluid charge line towards the second fluid line via the second supply line.

15. The drilling machine of claim 10, wherein, upon the supply of the additional fluid by the accumulator, the pressure in at least one of the first fluid line and the second fluid line is at least equal to a charge pressure in the fluid charge line.

16. The drilling machine of claim 10, wherein the drive pump includes a bi-directional pump.

17. The drilling machine of claim 10, wherein the at least one drilling component includes a drill pipe, a drill bit, or a hammer.

18. A method of operating a transmission system of a drilling machine, the method comprising:

operating a drive pump of the transmission system, wherein the transmission system further includes a charge pump and a fluid charge line that are in fluid communication with the drive pump;

operating a motor of the transmission system based on operation of the drive pump, wherein the transmission system further includes a first fluid line that fluidly couples the motor with the drive pump and a second fluid line that fluidly couples the motor with the drive pump; and

operating, in an event of a change in a load on the transmission system, an accumulator of the transmission system to supply additional fluid towards at least one of the first fluid line and the second fluid line to prevent a reduction in a pressure in at least one of the first fluid line and the second fluid line below a recommended operating level of at least one of the drive pump and the motor, wherein the accumulator is disposed in the fluid charge line and in selective fluid communication with the first fluid line and the second fluid line.

19. The method of claim 18, wherein, upon the supply of the additional fluid by the accumulator, the pressure in at least one of the first fluid line and the second fluid line is at least equal to a charge pressure in the fluid charge line.

20. The method of claim 18 further comprising operating, by the motor, at least one drilling component of the drilling machine based on the operation of the motor.