JP2021119029A - Rock drilling machine - Google Patents

Abstract

To provide a rock drilling machine which can correspond to increase of power density.SOLUTION: This rock drilling machine 10 comprises a rotation transmission part having: a shunk rod 40 on an outer face of which an outer diameter square spline 52 is formed; and a chuck 50 on an inner face of which an inner diameter square spline 51, which transmits a torque to the outer diameter square spline 52 of the shunk rod 40 and is so fitted to the outer diameter square spline as to be slidable along an axial direction, is formed. A material of the chuck 50 is a copper alloy having a heat conductivity of 200 W/(m K) or more, and oil mist supply means for supplying oil mists is provided at a contact place between the outer diameter square spline 52 and the inner diameter square spline 51.SELECTED DRAWING: Figure 1

Description

The present invention relates to a drilling machine, and more particularly to a rotation transmission unit of the drilling machine.

As a rotation transmission unit of this type of rock drill, for example, the technique described in Patent Document 1 is disclosed. The rock drill described in the same document will be described with reference to FIG. 3 as appropriate.

This type of rock drill is equipped with known striking and rotating mechanisms. As shown in FIG. 3, the rotation mechanism includes a shank rod 140, a chuck 150, a chuck driver 160, and a drive gear 134, and the drive gear 134 is rotationally driven by a motor (not shown). The contact point between the drive gear 134 and the chuck driver 160 is a gear mechanism, and the contact point between the shank rod 140 and the chuck 150 is the transmission of rotational driving force and the axial direction by spline fitting portions formed on the inner and outer diameters. It is fitted so that it can slide along.

That is, when the drive gear 134 is rotationally driven by the drive of the motor, the rotational driving force is transmitted from the chuck driver 160 to the shank rod 140 via the chuck 150 to rotate the shank rod 140. Further, the shank rod 140 can be moved back and forth by a predetermined distance along the axial direction by the spline fitting portions having inner and outer diameters provided at the contact points between the shank rod 140 and the chuck 150.

Further, the striking mechanism has a striking piston 120 and a switching valve (not shown), and the striking piston 120 moves back and forth according to the switching of the oil passage by the switching valve so as to strike the rear end portion of the shack rod 140. It has become. When the shank rod 140 is hit by the hitting piston 120, the hitting energy is transmitted to a rod and a bit (not shown), and the rotational driving force of the rotation mechanism described above is transmitted to the rod and the bit to crush the bedrock. That is, in this type of rock drill, the shank rod 140 is configured to be able to transmit a rotational force while being slid and held back and forth by the chuck 150.

Here, the shank rod requires the same strength as the striking piston that repeatedly strikes the rear end portion. Therefore, alloy steel such as nickel chrome molybdenum steel is used as the material of the shank rod. On the other hand, in the chuck, the spline groove having an inner diameter, which is a contact point with the shank rod, is required to cope with both wear due to sliding and surface pressure due to rotation. Therefore, as for the material of the chuck, a copper alloy such as aluminum bronze is adopted as a material having both wear resistance and high strength.

By the way, as a general specification of a rock drill, the striking speed of the striking mechanism is 2000 to 3000 bpm, and the rotation speed of the rotating mechanism is 100 to 300 rpm. Therefore, the spline fitting portion having an inner and outer diameter, which is a contact point between the shank rod and the chuck, is exposed to a high-speed sliding and high torque state.

As described above, the chuck uses a copper alloy as a material having both wear resistance and high strength, but the life of the chuck is inevitably shortened by itself. Therefore, as disclosed in Patent Document 2, an attempt has been made to reduce wear of the chuck by supplying lubricating oil to the contact portion between the chuck and the shank rod.

Japanese Unexamined Patent Publication No. 2000-52278 Japanese Unexamined Patent Publication No. 2013-518198

However, in recent rock drills, the output has been further increased, and the conventional chuck material selection and lubrication methods disclosed in Patent Documents 1 and 2 may not be able to cope with the wear of the chuck. ing.

That is, in the shank rod and chuck, which are the rotation transmission parts of the rock drill, the contact state of the spline fitting part is the surface pressure for each of a plurality of spline teeth or spline grooves due to manufacturing error and wear due to use. It is inevitable that there will be non-uniformity in the spline teeth or in the plane of the spline groove, and under harsh usage conditions, local stress concentration will occur in such non-uniformity. There is a problem that the chuck becomes worn at an early stage due to an abnormally high temperature, which causes a decrease in strength.
Therefore, the present invention has been made by paying attention to such a problem, and an object of the present invention is to provide a rock drill that can cope with high output.

In order to solve the above problems, the rock drill according to one aspect of the present invention transmits a rotational force to a shank rod having spline teeth formed on the outer surface and spline teeth of the shank rod and along the axial direction. It is a rock drill provided with a rotation transmission portion having a chuck having a spline groove formed on the inner surface to be slidably fitted, and the material of the chuck has a thermal conductivity of 200 W / (m · K). ) The above copper alloy, characterized in that it has an oil mist supply means for supplying oil mist to the contact points between the spline teeth and the spline grooves.

According to the rock drill according to one aspect of the present invention, the material of the chuck is a copper alloy having a thermal conductivity of 200 W / (m · K) or more, and the spline teeth and the spline grooves are in contact with each other by the oil mist supply means. Since the oil mist is supplied to the portion, the contact portion between the shank rod and the chuck can be cooled and lubricated.
Therefore, even if local stress concentration occurs at the contact part between the shank rod, which is the rotation transmission part, and the chuck and the temperature rises, the thermal conductivity of the chuck is good, so that the temperature rise diffuses throughout the chuck. Local high temperature conditions are prevented or suppressed. Further, since the oil mist cools and lubricates the chuck, premature wear of the chuck can be suppressed. Therefore, according to the rock drill according to one aspect of the present invention, it is possible to sufficiently cope with high output of the rock drill.

According to the present invention, it is possible to cope with high output of the rock drill.

It is explanatory drawing which shows one Embodiment of the rotation transmission part of the rock drill which concerns on one aspect of this invention, and FIG. (B) shows the ZZ cross section in (a). It is a figure (photograph) which compares the wear state of the chuck which concerns on this invention, and the conventional chuck. It is a vertical cross-sectional view which shows an example of the rotation transmission part of the conventional rock drill.

Hereinafter, an embodiment of the rotation transmission unit of the rock drill according to one aspect of the present invention will be described with reference to the drawings as appropriate. The drawings are schematic. Therefore, it should be noted that the relationship, ratio, etc. between the thickness and the plane dimension are different from the actual ones, and there are parts where the relationship and ratio of the dimensions are different between the drawings. Further, the embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention describes the material, shape, structure, and arrangement of constituent parts. Etc. are not specified in the following embodiments.

As shown in FIG. 1, the rock drill 10 of the present embodiment includes a rotation mechanism 30, a damper mechanism 70, a swivel mechanism 80, and a known striking mechanism 100. The striking mechanism 100 has a striking piston 20 and a known switching valve mechanism (not shown), and the striking piston 20 repeatedly moves forward and backward due to the switching operation of the oil passage by the switching valve mechanism, and the front end surface 21 of the striking piston 20 The rear end surface 41 of the shank rod 40, which will be described later, is hit.

The rotation mechanism 30 includes a housing having a front head 31 and a front cover 32 provided in front of the front head 31. A front cap 81 is attached to the tip of the front cover 32, and a motor 33 is attached to the rear of the front head 31. Inside the front head 31, a drive gear 34 connected to the output shaft of the motor 33 is rotatably supported. Inside the front cover 32, a cylindrical front ring 35 is provided at a position where it abuts on the rear end surface of the front cap 81, and the shank rod 40 is supported coaxially with the front ring 35.

The shank rod 40 has an outer diameter angle spline 42 which is a plurality of spline teeth evenly arranged in the circumferential direction at its rear portion, and its rear end surface 41 is hit by the front end surface 21 of the striking piston 20. It is a hit surface. A known threaded portion (not shown) is provided at the front end of the shank rod 40. An intermediate portion of the outer peripheral surface of the shank rod 40 is a sliding contact portion 43, and a water hole 44 communicating with the end surface of the threaded portion is coaxially formed inside the shank rod 40. The base end side of the water hole 44 is open to the side of the sliding contact portion 43.
Further, inside the front cover 32, the chuck 50 and the chuck driver 60 are mounted at the rear positions of the shank rod 40.

As shown in FIG. 3B, the chuck 50 is formed with an inner diameter angle spline 51 which is a plurality of spline grooves evenly arranged in the circumferential direction on the inner peripheral surface thereof, and the outer peripheral surface thereof is formed in the circumferential direction. Outer diameter angle splines 52, which are a plurality of spline teeth evenly arranged in the same direction, are formed. The inner diameter angle spline 51 of the chuck 50 is spline-fitted with the outer diameter angle spline 42 of the shank rod 40.
Further, as shown in FIG. 6A, end face slits 53, 53'extending in the radial direction are provided on the front and rear end faces of the chuck 50, and further, the chuck 50 communicates with the end face slits 53, 53'. Inner diameter grooves 54 and 54'are formed on the inner peripheral surface of the chuck 50, and a communication hole 55 penetrating in the radial direction is provided in the central portion of the chuck 50.

The chuck driver 60 is provided with an outer diameter gear portion 64 that meshes with the drive gear 34 at a position rearward of the outer peripheral surface, and a cylindrical chuck driver bush 65 is coaxially slid on the rear portion. The front end surface 66 of the chuck driver bush 65 is in contact with the rear end surface 41 of the shank rod 40, and an end surface slit 67 is formed at the rear end portion along the radial direction.

Further, in the chuck driver 60, inner diameter angle splines 61, which are a plurality of spline grooves evenly arranged in the circumferential direction, are formed on the inner peripheral surface. The inner diameter angle spline 61 of the chuck driver 60 is spline-fitted with the outer diameter angle spline 52 of the chuck 50 (see FIG. 3B). Further, in the chuck driver 60, an inner diameter ring groove (large) 62 is formed on the inner peripheral surface rearward in the axial direction, and an inner diameter ring groove (small) 63 is formed on the rear end surface.

Here, in the front head 31, a third communication hole 36 is formed through the thick portion on the inner peripheral side in the axial direction. The front cover 32 is formed with an oil mist discharge port 37 penetrating along the radial direction at the front end portion. Further, in the chuck driver 60, the fourth communication hole 68 is obliquely connected to the third communication hole 36 and the inner diameter annular groove (large) 62 in the thick portion provided with the outer diameter gear portion 64. Further, the fifth communication hole 69 is formed obliquely so as to communicate with the diameter ring groove (small) 63.

The damper mechanism 70 has a damper housing 71, and a pushing piston 72 and a damping piston 73 coaxially housed in the damper housing 71. The damper housing 71 is provided with an oil mist introduction port 74 at an upper position rearward in the axial direction. The oil mist introduction port 74 communicates with the first communication hole 75, which is a vertical hole formed through the radial direction, and the middle portion of the first communication hole 75 becomes a thick portion on the upper side of the damper housing 71. , It is formed so as to communicate with the second communication hole 76, which is a horizontal hole penetrating along the axial direction.

The swivel mechanism 80 has a front cap 81 and a swivel body 82 provided in the front cap 81. The swivel body 82 has a seventh communication hole 84 formed through the rear end side in the radial direction, and the front cap 81 has an eighth communication hole 83 in the radial direction at a position communicating with the seventh communication hole 84. It is formed through coaxially, and the 7th communication hole 84 and the 8th communication hole 83 communicate with the oil mist discharge port 37.

Then, in the present embodiment, an oil mist path 90 is configured as an oil mist supply means for supplying the oil mist to the spline fitting portion described above. In the oil mist path 90 of the present embodiment, the inlet of the oil mist is the oil mist introduction port 74, the outlet is the oil mist discharge port 37, and the lubrication space, the clearance, and the lubrication space thereof formed by the constituent members are formed. It consists of a communication hole that connects the clearance and the clearance to each other.

Specifically, in the present embodiment, the first lubrication space 91 is defined by the outer diameter of the striking piston 20, the inner diameter of the pushing piston 72, and the inner diameter of the chuck driver bush 65, and the second lubrication space 92 is the front head 31. It is defined by the inner wall and the outer diameter gear portion 64, and further, the third lubrication space 95 is defined by the inner diameter of the front ring 35 and the sliding contact portion 43.

Further, as shown in FIG. 3B, the first clearance 93 is formed at the contact portion between the inner diameter angle spline 61 and the outer diameter angle spline 52, which is the spline fitting portion on the outer peripheral side, and the second clearance 94 is formed. Is formed at the contact portion of the outer diameter angle spline 42 with the inner diameter angle spline 51, which is the spline fitting portion on the inner peripheral side.

The first passage 75 described above connects the oil mist introduction port 74 and the first lubrication space 91. Further, the second passage 76 and the third passage 36 connect the first passage 75 and the second lubrication space 92. Further, the fourth communication hole 68 and the inner diameter annular groove (large) 62 connect the second lubrication space 92 and the first clearance 93.

Further, the fifth communication hole 69, the diameter ring groove (small) 63, the end face slit 53'and the inner diameter groove 54'connect the second lubrication space 92 and the second clearance 94. Further, the sixth communication hole 55 connects the first clearance 93 and the second clearance 94, and the seventh communication hole 84 and the eighth communication hole 83 are connected to the third lubrication space 95 and the oil mist discharge port 37. Is connected.

Further, the first clearance 93 and the second clearance 94 shown in FIG. 6B are also connected by the end face slit 53 and the inner diameter groove 54, and the second clearance 94 and the fifth lubrication space 95 are connected by the inner diameter groove 54. It is connected.
The shank rod 40 is momentarily advanced by the impact of the striking piston 20, and at the time of this advancement, the contact state between the rear end surface 41 of the shank rod 40 and the front end surface 21 and the front end surface 66 of the striking piston 20 is released. , The first lubrication space 91 and the second clearance 94 are configured to communicate with each other.

Here, the properties of the chuck 50 will be described.
Table 1 is a comparison table of thermal conductivity, hardness, and elongation among the physical and mechanical properties of the present embodiment and Comparative Examples 1 to 3. Table 2 is a comparison table of the compositions of the present embodiment and Comparative Examples 1 to 3 (unit: wt%). Comparative Example 1 is aluminum bronze, Comparative Example 2 is special high-strength brass, and Comparative Example 3 is phosphor bronze, all of which are copper alloy materials often used for chucks of rock drills.
As shown in Table 2, the material of the chuck 50 of the present embodiment is Ni: 1.5 to 3.0 wt%, Si: 0.5 to 1.5 wt%, Cr: 0.5 to 1.5 wt%, Sn: 0.1 to 0.3 wt%, and the balance is a copper alloy composed of Cu and unavoidable impurity elements.

As shown in Table 1, the present embodiment and Comparative Examples 1 to 3 have substantially the same values in terms of hardness and elongation, but the values of the present embodiment are the values of Comparative Example 1 in terms of thermal conductivity. It can be seen that it is remarkably high with respect to ~ 3.
Here, if the thermal conductivity is smaller than 200 W / (m · K), a local abnormal high temperature occurs. Since it is essential for the hardness of the chuck 50 to be 80 HRB or more from the viewpoint of the function of the chuck 50, the chuck 50 according to the present invention is substantially limited to the copper alloy, and is oxygen-free. The thermal conductivity of copper, 391 W / (m · K), can be considered to be outside the scope of the present invention, that is, the upper limit of the thermal conductivity.

Next, the oil mist supplied to the above-mentioned oil mist path 90 will be described.
Oil mist is generated by dripping and mixing compressed air supplied from a compressor (both not shown) mounted on a trolley equipped with a rock drill 10 and lubricating oil with a lubricator (not shown). ..
The conditions of the oil mist in this embodiment are that the air volume is 0.1 m ³ / min or more and 0.6 m ³ / min or less, and the oil consumption per air volume is 10 cc / m ³ or more and 25 cc / m ³ or less. .. If the air volume is ^{less than 0.1 m 3} / min, the chuck 50 will not be cooled sufficiently, and if it ^{is larger than 0.6 m 3} / min, the amount of oil will increase. If the amount of oil consumed per air volume ^{is less than 10 cc / m 3} , the lubricating film will be insufficient, and if it ^{is larger than 25 cc / m 3} , the mist state will become unstable, lubrication spots will occur, and the oil will be discharged to the outside of the machine. The amount of lubricating oil increases and the working environment deteriorates.

Next, a case where the drilling work is performed by the drilling machine 10 of the present embodiment will be described.
When performing drilling work with the drilling machine 10, the striking mechanism 100 is operated, the striking piston 20 strikes the rear end surface 41 of the shank rod 40, the motor 33 is driven, and the chuck driver is used from the drive gear 34. The rotational driving force is transmitted to the shank rod 40 via the spline fitting portion of the 60 and the chuck 50. A sleeve, a replenishment rod, and a tip bit (not shown) are connected to the shank rod 40, and the impact and rotation generated by the shank rod 40 are transmitted to the tip bit to crush the bedrock.

The damper mechanism 70 operates so as to buffer the striking energy that is reflected and returned without being completely consumed by the bedrock, and keeps the tip bit and the bedrock in good contact with each other. The swivel mechanism 80 supplies the flushing fluid from a flushing fluid supply source (not shown) to the tip bit through the water hole 44 to discharge the powder.

Here, the contact points between the inner diameter angle spline 51 and the outer diameter angle spline 42 are in a high-speed sliding and high torque state during the drilling operation. Then, due to manufacturing errors and wear due to use, the contact state between the square splines is a place where the surface pressure becomes non-uniform for each of a plurality of spline teeth or spline grooves, or within the surface of the spline teeth or spline grooves. However, in such a non-uniform place, heat due to local stress concentration may be generated.

On the other hand, in the rock drill 10 of the present embodiment, the material of the chuck is a copper alloy having a thermal conductivity of 200 W / (m · K) or more, so even if heat is locally generated, the chuck is used. The thermal conductivity of 50 is good. Therefore, the heat generation is diffused to the entire chuck 50, and the local high temperature state is prevented or suppressed.
Further, in the rock drill 10 of the present embodiment, since the oil mist is supplied to the oil mist path 90, sufficient cooling action and lubrication are performed at the contact points between the spline teeth and the spline grooves. Therefore, it is possible to prevent the chuck 50 from being worn out at an early stage.

FIG. 2A is a photograph showing a wear state after the chuck 50 of the present embodiment is used for drilling work for 500 hours, and FIG. 2B is a photograph showing the chuck of Comparative Example 1 for drilling work. It is a photograph which shows the wear state after using for 50 hours. Although the wear state depends on the conditions of drilling work (whether the crushing target is hard rock or soft rock, etc.), the chuck 50 of the present embodiment is approximately 10 times as large as the chuck of Comparative Example 1. It was confirmed that it has the above life.

Although one embodiment of the rock drill according to the present invention has been described above with reference to the drawings and the table, the rotation transmission unit of the rock machine according to the present invention is not limited to the above embodiment, and the invention. Of course, it is permissible to change various other modifications and components without deviating from the purpose of.

10 Drilling machine 20 Strike piston 21 Front end surface 30 Rotating mechanism 31 Front head 32 Front cover 33 Motor 34 Drive gear 35 Front ring 36 Third communication hole 37 Oil mist discharge port 40 Shank rod 41 Rear end surface 42 Outer diameter angle spline 43 Contact part 44 Water hole 50 Chuck 51 Inner diameter angle spline (spline groove)
52 Outer diameter angle spline (spline tooth)
53, 53'End face slit 54, 54' Inner diameter groove 55 6th communication hole 60 Chuck driver 61 Inner diameter angle spline 62 Inner diameter annulus groove (large)
63 Inner diameter annulus groove (small)
64 Outer diameter gear part 65 Chuck driver bush 66 Front end face 67 End face slit 68 4th communication hole 69 5th communication hole 70 Damper mechanism 71 Damper housing 72 Pushing piston 73 Damping piston 74 Oil mist introduction port 75 1st communication hole 76 2nd Communication hole 80 Swivel mechanism 81 Front cap 82 Swivel body 83 8th communication hole 84 7th communication hole 90 Oil mist path 91 1st lubrication space 92 2nd lubrication space 93 1st clearance 94 2nd clearance 95 3rd lubrication space 100 Strike mechanism

In order to solve the above problems, fences Iwaki according to one embodiment of the present invention, a shank rod Rutotomoni own rear end first spline teeth formed on the outer surface is hit by the striking piston, the shank rod chuck first spline grooves slide along the axial direction is fitted can be formed on the inner surface and the second spline teeth formed on the outer surface while transmitting the rotational force to the first spline teeth When a second spline groove to be fitted on the second spline teeth of the chuck comprises a rotation transmitting portion having a chuck driver formed on an inner surface, the first spline teeth and the first the contact portion and the second spline teeth and the contact portion of the second spline grooves mutual spline grooves cross, possess oil mist supply passage for supplying the oil mist, the chuck is communicating penetrating in the radial direction A hole is provided, and the communication hole constitutes a part of the oil mist supply path, and the contact point between the first spline tooth and the first spline groove and the second spline tooth and the second spline tooth It is characterized in that the contact points of the second spline grooves are communicated with each other in the radial direction.

According to the rock drill according to one aspect of the present invention, the oil mist supply path, the contact of the first contact portion of the spline teeth and first spline grooves cross, and second spline teeth and second spline grooves mutually Since the oil mist is supplied to the portion, the contact portion between the shank rod and the chuck and the contact portion between the chuck driver and the chuck can be cooled and lubricated.
In particular, the chuck is provided with a communication hole that penetrates in the radial direction, and this communication hole forms a part of the oil mist supply path and forms a contact point between the first spline tooth and the first spline groove. The contact points between the second spline tooth and the second spline groove are made to communicate with each other in the radial direction.
Therefore, even when the temperature is increased local stress concentration at the contact portion between the contact portion and the chuck driver and chuck shank rod and the chuck is rotating transmission unit occurs, it prevents the localized high temperature Or it is suppressed. Further, since the oil mist cools and lubricates the chuck and each spline portion inside and outside the chuck, premature wear of the chuck can be suppressed. Therefore, according to the rock drill according to one aspect of the present invention, it is possible to sufficiently cope with high output of the rock drill.

Claims (3)

A shank rod with spline teeth formed on the outer surface, and a chuck with spline grooves formed on the inner surface that transmit rotational force to the spline teeth of the shank rod and are fitted so that they can slide along the axial direction. It is a rock machine equipped with a rotation transmission part with
The material of the chuck is a copper alloy having a thermal conductivity of 200 W / (m · K) or more.
A rock drill having an oil mist supply means for supplying oil mist at a contact point between the spline teeth and the spline grooves. The oil mist has an air volume of 0.1 m ³ / min or more and 0.6 m ³ / min or less, and an oil consumption per air volume of 10 cc / m ³ or more and 25 cc / m ³ or less. Rock machine described in. The material of the chuck is Ni: 1.5 to 3.0 wt%, Si: 0.5 to 1.5 wt%, Cr: 0.5 to 1.5 wt%, Sn: 0.1 to 0.3 wt%, The rock drill according to claim 1 or 2, wherein the balance is a copper alloy composed of Cu and an unavoidable impurity element.

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