Patent Application
20140360743
This application claims priority under 35 U.S.C. ยง119 to EP Patent Application No. 13171045.1, filed on Jun. 7, 2013, which the entirety thereof is incorporated herein by reference.
The present disclosure relates to a rock drilling machine, and particularly to an arrangement for lubricating the rock drilling machine. A rotating sleeve is arranged around a shank in order to transmit rotation generated by a rotating device to the shank. The rotating sleeve and the shank are provided with a gear system for transmitting the rotation. Further, the rock drilling machine comprises a lubricating system for feeding a pressurized lubricating fluid to the gear system.
The disclosure further relates to a rotating sleeve and a method of lubricating a rock drilling machine.
In mines and at other work sites, rock drilling machines are used for drilling bore holes into rock surfaces. The rock drilling machine includes a rotating device for rotating a drilling tool during drilling. The tool is connected to a shank which is bearing mounted to a body of the drilling machine. A rotating torque generated by the rotating device is transmitted to the shank by means of a rotating sleeve arranged around the shank. Between the rotating sleeve and the shank is provided a gear system. In the gear system, a tooth contact occurs between gear teeth and, consequently, the gear system is subjected to wear. Lubricating systems have been developed for delivering lubricating oil between operating flanks of the teeth of the gear system. However, the known lubricating systems have drawbacks.
An object of the disclosure is to provide a novel and improved rock drilling machine provided with a lubricating system, a rotating sleeve and a method of lubricating a rock drilling machine.
The rock drilling machine according to the disclosure is characterized in that the tooth contact between the first gear and the second gear comprises operational flank surfaces between opposing teeth, at least one flank surface in each tooth contact is provided with at least one groove, and the feed duct of the lubricating system is in connection with the grooves, allowing the lubricating fluid to be fed to the tooth contact and to flow in the at least one groove of the flank surface.
The method according to the disclosure includes producing a flow of lubricating fluid in grooves of operational flank surfaces of teeth of the gears and maintaining the flow in the grooves during transmission of rotation, whereby the flow of the lubricating fluid lubricates the operational flank surfaces.
The rotating sleeve has at least one elongated groove in each of the first flank surfaces, and wherein each of the grooves has at least one open end and is connected to the feed duct.
The rock drilling machine includes a lubricating system for feeding lubricating fluid to a gear system between a rotating sleeve and a shank. A tooth contact between a first gear of the shank and a second gear of the rotating sleeve has operational flank surfaces between opposing teeth of the gearings. Thus, the operational flank surfaces of the opposing teeth are facing towards each other. At least one of the two opposing flank surfaces in each tooth contact is provided with at least one groove. The feed duct or another flow path of the lubricating system is in connection with the grooves, allowing the lubricating fluid to be fed to the tooth contact. In other words, at least one groove is provided in at least one of the abutting faces of a pair of splines for serving as a flow path for the lubricating fluid to provide effective lubrication and cooling effect to each spline face.
An advantage is that proper lubrication is achieved for the gear system between the rotating sleeve and the shank, whereby service life can be longer and operational reliability can be improved.
According to an embodiment, the lubricating fluid is arranged to flow in the tooth contact between gears of the rotating sleeve and the shank. The produced flow of lubricating fluid is also maintained during transmission of rotation. An advantage of this embodiment is that the flow of the lubricating fluid lubricates effectively operational flank surfaces of teeth of the gears. Further, the flow of the lubricating fluid may absorb heat and transport it away from the gears. Thus, the lubricating system may also serve as a cooling system. One additional benefit may be that the flowing fluid may transport impurities away from a gear system.
According to another embodiment, opposing teeth of the gears have flank surfaces facing towards each other. At least one of the two opposing flank surfaces in each tooth contact is provided with at least one groove. The groove is elongated and is in an axial direction.
According to yet another embodiment, the above-disclosed groove in the flank surface is elongated and has a first end and a second end. At least one end of the groove is open, which allows the lubricating fluid fed to the groove to flow in the groove towards the open end. The feed duct may be located in a closed end portion of the groove. Further, the open end of the groove may be located at a tool side end of the gearing and the closed end of the groove may be located on an opposite end of the gear. Then the lubricating fluid may flow towards the tool side in the groove.
According to still another embodiment, the groove in the flank surface is elongated and has a first end and a second end. Both ends of the groove are open, which allows the lubricating fluid fed to the groove to flow in the groove towards the open ends. The feed duct may be located between the ends of the groove.
In another embodiment, the groove in the flank surface is elongated and has a first end and a second end. Both ends of the groove are closed. The groove is in connection to a feed duct and to a discharge duct. The feed duct and the discharge duct are located in opposite end portions of the groove. The lubricating fluid fed from the feed duct flows in the groove towards the discharge duct. The feed duct and the discharge duct are in a transverse direction relative to a longitudinal direction of the groove, whereby the ducts may be in a radial direction or slightly angled. This embodiment offers yet another additional solution for producing a flow of lubricating fluid in the groove.
The operational flank surfaces of the teeth of the second gear in the rotation sleeve are provided with such grooves.
According to another embodiment, the rock drilling machine includes a lubricating system for feeding lubricating fluid to a gear system between a rotating sleeve and a shank and further to one or more bearings of the rotating sleeve. An advantage of this embodiment is that proper lubrication is achieved for the bearings of the rotating sleeve, whereby service life can be longer and operational reliability can be improved. In this embodiment at least one feed duct of the lubricating system is connected to the bearing space surrounding the rotating sleeve and the lubricating fluid is arranged to lubricate the at least one second bearing of the rotating sleeve.
According to still another embodiment, the lubricating fluid lubricates at first one or more bearings of the rotating sleeve and only thereafter is the lubricating fluid arranged to flow to the gearing system for lubricating opposing flank surfaces of teeth of the gears. The pressure of the lubricating fluid is still high enough when entering the bearing space, and further, the lubricating fluid does not contain impurities when at first entering the bearing space. Thus, proper lubrication of the bearings of the rotating sleeve can be ensured.
According to an embodiment, the lubricating fluid is fed to the bearing space surrounding the rotating sleeve through at least one bearing supporting the rotating sleeve. Then at least one feed duct of the lubricating system is located at the bearing of the rotating sleeve. When the lubricating fluid is fed through a structure of the bearing, proper lubrication of the bearing can be ensured in all circumstances.
According to another embodiment, the lubricating fluid is fed to the bearing space surrounding the rotating sleeve through at least one bearing in a radial direction.
According to yet another embodiment, the lubricating fluid is fed to the bearing space surrounding the rotating sleeve through at least one bearing in an axial direction.
According to an embodiment, the rotating sleeve located in the bearing space is supported against the body by means of a front bearing and a rear bearing. The front bearing is located at a tool side end of the sleeve and the rear bearing at an opposite end. The lubricating fluid is fed through the rear bearing. Then at least one feed duct of the lubricating system is located at the rear bearing. This embodiment ensures effective lubrication of the rear bearing, which is subjected to great stress and wear during drilling.
According to still another embodiment, the rotating sleeve located in the bearing space is supported against the body by means of a front bearing and a rear bearing. The front bearing is located at a tool side end of the sleeve and the rear bearing at an opposite end. The lubricating fluid is fed through the front bearing.
According to another embodiment, the rotating sleeve located in the bearing space is supported against the body by means of a front bearing and a rear bearing. The front bearing is located at a tool side end of the sleeve and the rear bearing at an opposite end. The lubricating fluid is fed through the front and rear bearings.
According to another embodiment, the rotating sleeve located in the bearing space is supported against the body by means of a front bearing and a rear bearing. The front bearing is located at a tool side end of the sleeve and the rear bearing at an opposite end. The lubricating fluid is fed to the bearing space surrounding the rotating sleeve through a middle channel provided between the front bearing and the rear bearing.
According to yet another embodiment, the rotating sleeve is provided with several fluid ducts, channels, grooves or other flow paths for conveying the lubricating fluid from the bearing space of the rotating sleeve to the tooth contact between the first gear of the shank and the second gear of the rotating sleeve. According to this embodiment, the lubricating fluid lubricates at first the bearings located in the bearing space of the rotating sleeve, and subsequently it lubricates a gear system. Thus, the lubricating fluid is utilized in at least two successive places requiring effective lubrication.
According to another embodiment, the lubricating fluid is arranged to flow towards the tooth contact between gears of the rotating sleeve and the shank through a dedicated flow path or channel without first passing through bearings of the rotating sleeve. Thus, the drilling machine may comprise separate channels for conveying the lubricating fluid to the grooves of the flank surfaces.
According to still another embodiment, the rock drilling machine is provided with a rear space on a side of the rear end of the shank. One or more gas feed ducts are connected to the rear space, allowing the rear space to be pressurized by feeding a pressurized gas to the rear space. The pressurized gas is allowed to leak from the rear space towards the first end of the shank, whereby a gas flow flushes the lubricating fluid of the lubricating system towards the first end of the shank. The fed gas flows to collecting ducts and means of the lubricating system, whereby the fed gas assists a returning flow of the lubricating fluid towards a tank or a corresponding reservoir of the lubricating system.
According to an embodiment, the rock drilling machine includes a percussion device on a rear side of the shank. The percussion device comprises a percussion piston, which is on a same axial line as the shank. Opposing rear end of the shank and front end of the percussion piston are located in a rear space formed in a body of the rock drilling machine. The opposing ends are provided with impact surfaces facing towards each other in a rear space. A pressurized gas is fed to the rear space in order to flush the rear space with a gas flow. Thanks to the flushing, possible oil, particles and impurities can be removed from the rear space, preventing them from getting between the impact surfaces and causing damages. The gas flow may also flush the impact surfaces. An additional benefit is that by pressurizing the rear space, leakage of hydraulic oil through seals of the percussion piston can be decreased or prevented completely. The gas flow may also be utilized in cooling of the bearings, seals and impact surfaces.
According to yet another embodiment, the rock drilling machine has a percussion device located on a rear side of the shank. The percussion device includes a percussion piston, which is on a same axial line as the shank. A front end of the percussion piston and a rear end of the shank are provided with impact surfaces. The percussion piston comprises at least one flushing duct in a longitudinal direction of the percussion piston. The flushing duct is connected to a flushing system, allowing a pressurized gas to be fed to the flushing duct. The flushing duct leads the pressurized gas to the impact surface of the percussion piston, whereby the gas flushes the impact surface. An advantage of this embodiment is that when the flushing gas is fed through the impact surface, the flushing is effective and a flow rate may be low. Any oil that has leaked from a hydraulic circuit is flushed away from the impact surface, whereby the service life of the percussion piston may longer.
According to an embodiment, the pressurized gas used in flushing is oil free pressure air. The flushing system may comprise one or more compressors for producing the necessary pressure air. The pressurized air may be filtered so that oil is separated from the air.
According to an embodiment, the rock drilling machine is provided with a circulation lubrication system. Then the lubricating fluid is circulated in a lubricating circuit comprising at least: a tank, a pump, feed ducks and collecting ducks. The lubricating circuit is separate from a hydraulic circuit of the rock drilling machine. The lubricating fluid pressurized by the pump is fed to a bearing space of the rotating sleeve and is circulated via feed ducks to defined lubricating points in the rock drilling machine. Finally the lubricating fluid is collected by the collecting ducts and is returned to the tank of the system so that it can be reused. The lubricating fluid may be filtered during the circulation.
According to an embodiment, the lubrication fluid is also arranged to flow through a gear box of the rotating device. Thus, the lubricating fluid may lubricate bearings of the rotating device, a gear system between the rotating device and an outer surface of the rotating sleeve, and any other transmission members inside the gear box.
According to an embodiment, the lubrication fluid is also used for lubricating one or more bearings of the shank. At least some of the fed lubrication fluid may be arranged to flow through a slide bearing of the shank. Before reaching the shank bearing the lubricating fluid has already circulated through the bearing space of the rotation sleeve and the gearing system. When the lubricating fluid leaves the shank bearing, it flows towards a tank of a circulation lubrication system.
According to another embodiment, the lubricating fluid fed to the bearing space is oil. The fed oil lubricates one or more bearings of a rotating sleeve and is thereafter led forward to lubricate a gearing system between the rotating sleeve and a shank. A flushing gas, such as pressure air, is fed to a rear space located at a rear end of the shank. At least some of the lubricating oil and the flushing gas is allowed to be mixed for producing an oil mist. The oil mist may be led forward to lubricate a gearing system between the rotating sleeve and a rotating device, bearings of the rotating device, bearings of the shank and possibly any other lubricating points located around the shank. The oil and the oil mist may be collected after being circulated through the designed lubricating points. This embodiment provides effective circulation of the lubrication fluid.
According to still another embodiment, the lubricating fluid fed to the bearing space is oil mist. The fed oil mist lubricates one or more bearings of a rotating sleeve and is thereafter led forward to lubricate a gearing system between the rotating sleeve and a shank. A flushing gas, such as oil free pressure air, is fed to a rear space located at a rear end of the shank. The flushing gas may assist the oil mist to flow towards succeeding lubricating points. The oil mist may be led forward to lubricate a gearing system between the rotating sleeve and a rotating device, bearings of the rotating device, bearings of the shank and possibly any other lubricating points locating around the shank. The oil mist may be collected after being circulated through the designed lubricating points. This embodiment provides effective circulation of the lubrication fluid.
According to an embodiment, the lubricating fluid is fed to a bearing space surrounding the rotating sleeve under a pressure of 12 bar. The pressure of the lubricating fluid may be 10 to 12 bar. This pressure level is enough for causing the fed lubricating fluid to flow through the feed ducts to the predetermined lubrication points.
According to the embodiments, the lubricating fluid can be oil, transmission oil, or oil mist comprising pressurized gas, such as air, and oil.
According to an embodiment, the lubricating fluid is isolated from a hydraulic system and hydraulic fluid in the hydraulic system.
According to another embodiment, the lubricating fluid fed to the rock drilling machine is collected by collecting means having at least one reservoir. Thus, handling of the used lubricating fluid is controlled, whereby possible problems at a work site caused by the used lubricating fluid can be prevented.
According to another embodiment, the rotating sleeve includes two components, namely a first sleeve and a second sleeve. The sleeves are arranged within each other. The second sleeve is smaller in size and it is arranged inside the first sleeve. Between the first sleeve and the second sleeve are provided gears for transmitting rotation between the sleeves. Further, an outer surface of the outer first sleeve is provided with a gear for receiving torque from a rotating device. On an inner surface of the second sleeve is provided a gear, which transmits torque to the shank. The gearing, or drive coupling, between the inner second sleeve and the shank allows longitudinal movement of the shank along the axis of rotation. Because to this longitudinal movement, the gears of the second sleeve and the shank are subjected to great stresses and wear. When the rotating sleeve is formed of two components, the inner sleeve can be replaced when worn out.
According to another embodiment, the rotating sleeve includes two components arranged within each other, namely an outer first sleeve and an inner second sleeve. The second sleeve may be made of slide bearing material. For bearings the slide bearing material may be bronze.
According to another embodiment, the rotating sleeve includes two components arranged within each other, namely an outer first sleeve and an inner second sleeve. The inner second sleeve has splines which are provided with elongated grooves in an axial direction of the sleeve. The grooves are open at their front end, rear end or both ends. Alternatively, ends of the grooves are closed and the groove is in connection to a feed duct and a discharge duct. Thus, the grooves are not closed when flank surfaces of the splines are pressed against abutting splines of a shank. Then the grooves may serve as flow paths for a pressurized lubricant fluid fed to the grooves, whereby the flow of the lubricating fluid may provide effective lubrication and cooling.
According to another embodiment, the rock drilling machine is a down-the-hole (DTH) drilling machine having a rotating unit and a percussion unit arranged at opposite ends of a tool.
According to another embodiment, the rock drilling machine is a rotary drilling machine having a rotating unit. The rotary drilling machine is without any percussion device.
According to another embodiment, the rock drilling machine is a top hammer drilling machine having a rotating device and a percussion device located at a rear end of the tool. A rear end of the shank is provided with an impact surface for receiving impact pulses generated by the percussion device.
The above-disclosed embodiments can be combined in order to form suitable solutions provided with necessary features disclosed.
The foregoing summary, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown.
Some embodiments are described in more detail in the accompanying drawings, in which
For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.
The rock drilling machine 4 includes a lubricating system 23 for lubricating at least the rear bearing 15b of the rotating sleeve 14 and the first gear system 17, too. The lubricating system 23 may include a lubricating pump 24 for pressurizing a lubricating fluid and one or more feed ducts 25 for conveying the lubricating fluid to the bearing space 16. The lubricant fluid may be fed through the rear bearing 15b, whereby proper lubrication for the rear bearing 15b is ensured. The flow of the lubricating fluid continues its flow through ducts in the outer first sleeve 14a and in the inner second sleeve 14b towards the gear system 17. Some examples of these ducts are shown in
It is to be mentioned that in
In
In
Although the present embodiment(s) has been described in relation to particular aspects thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present embodiment(s) be limited not by the specific disclosure herein, but only by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 13171045.1 | Jun 2013 | EP | regional |
