CA2278036C

CA2278036C - Percussion movement apparatus

Info

Publication number: CA2278036C
Application number: CA002278036A
Authority: CA
Inventors: Myeong Soo Jang; Il Jae Lee; Kyung Chon Shin
Original assignee: Soosan Heavy Industries Co Ltd
Current assignee: Soosan Heavy Industries Co Ltd
Priority date: 1998-07-30
Filing date: 1999-07-19
Publication date: 2005-11-29
Anticipated expiration: 2019-07-19
Also published as: CA2278036A1; JP2000079579A; DE19935890A1; CN1247252A; CN1112281C; KR100287943B1; KR20000010132A

Abstract

In order to maximize percussion force and reduce the number of components and weight by installing a valve between a piston and a cylinder, the invention provides a percussion movement apparatus which comprises a valve installed between the piston and the cylinder, the valve being constructed to open/close a flow path and organically cooperate with the piston by predetermined movements thereof, the valve having substantially cylindrical overall shape whose both end surfaces which is upper and lower end surfaces thereof with different cross sectional areas, and also the valve including a longitudinal piston hole with multistage sills, a plurality of holes extending rectangularly to the piston hole for communicating the piston hole with exterior, and an annular projection with front and rear peripheral surfaces partially formed on a peripheral surface of the valve, the cylinder being mounted the outside of the valve and including a plurality of cylinder holes for reciprocating the piston; and a rear cover mounted on the rear of the valve and the cylinder, the piston, the cylinder and the valve having a plurality of chambers and a valve switching chamber defined by making a difference in diameter along a longitudinal direction for providing predetermined annular chambers between inner and outer peripheral surfaces thereof into which the fluid can be introduced, and the cylinder including a cylinder block formed with a plurality of fluid passages for inflow/discharge of a working oil.

Description

PERCUSSION MOV~MSNT APPARATUS
~T~r.~ OF THB INVgNTION
The present invention relates to a hydraulic percussion movement apparatus and more particularly to a percussion movement apparatus whose efficiency may be maximized by installing a shaped valve between a piston and a cylinder and making these hydraulic elements organically cooperate with one another for reciprocating the piston with high hydraulic pressure to strike/advance a shank at high speed.
F3ACKC~ROUND OF THE I11V»rrrzoN
Usually, drilling operations are preceded in subway tunneling, stone and mineral coring, aggregate production and rock work for reinforcement of a brittle ground. These drilling operations are divided into two classes; one is a rotary drilling operation that gives a low-speed rotary driving with a bit attached to a tip of the apparatus to drill a target, the other is a percussion/rotary drilling operation that does a percussion movement with a high-speed rotation movement to drill a target. In case of the latter, the operation is normally accomplished at a movement speed of 200 rpm/3000 bpm and an advance speed of 1.5 m/min, which case is similar to that of a pneumatic drill, but both cases are quite different in performance.
A percussion movement apparatus used in the percussion/rotary drilling operation employs an oil-hydraulic circuit to function as a hydraulic system under combination of various hydraulic element units. In this type of percussion movement apparatus, high hydraulic pressure is produced and circulated by means of a hydraulic pump that converts mechanical energy to pressure energy.
This apparatus using hydraulic pressure for percussion S movement necessarily requires hydraulic components of a piston, a cylinder and a valve to switch a direction of power derived from working oil.
In the hydraulic percussion movement apparatus, the hydraulic pump usually supplies high-pressure working oil through an inflow port into front and rear chambers. As the result of this, a high pressure is built up when the front and rear chambers of the cylinder are full of the working oil. The valve disposed to be opened and closed depending upon an area difference value between the front and rear chambers moves by a difference of pressures acting on upper and lower end surfaces of the valve so that the rear chamber may be connected with a low-pressure passage.
At this time, the piston reaches an upper dead point and simultaneously the high-pressure oil is supplied into a valve switching chamber via an oil passage extending from a lower end face of the cylinder to move the valve. This movement of the valve causes the rear chamber of the cylinder to be connected with the high-pressure oil passage simultaneously with the low-pressure oil passage blocked so that the piston may descend to strike a shank in the same axis of that of the piston.
To switch the valve, a valve plug, a valve tappet and so on are inevitably required.

RY OF TH$ INVENTION
As previously described, the percussion movement apparatus of the prior art requires the valve plug, the valve tappet and so on for switching the valve, and must be formed with very complicated multistage oil passages for delivering the high-pressure oil into the valve switching chamber of the valve and the rear chamber of the cylinder.
Moreover, size of the valve is larger because it should control a great deal of working oil, which leads to a problem that size and weight of the apparatus are also increased.
Taking into account the above-mentioned drawbacks, it is an object of the invention to eliminate these drawbacks and provide a percussion movement apparatus that makes it possible to maximize a percussion force, reduce the number of components and minimize/lighten volume/weight of the apparatus by installing a specific-constructed valve between a piston and a cylinder so that it may automatically switch a flow path of working oil acting on the piston and convert hydraulic energy to reciprocation energy even if basic working oil is only used.
To achieve this object, in a percussion movement apparatus comprising a main body containing at least components for creating percussion force, a piston for reciprocating within a cylinder to discharge high-pressure fluid supplied through an inflow port, a shank connected to an output stage of the piston, and a power generator unit for rotating the shank, the percussion movement apparatus comprises a valve installed between the piston and the cylinder, the valve being constructed to open/close a flow path and organically cooperate with the piston by predetermined movements thereof, the valve having substantially cylindrical overall shape whose both end surfaces which are upper and lower end surfaces thereof with different sectional areas, and also the valve including a longitudinal piston hole with multistage sills, a plurality of holes extending rectangularly to the piston hole for communicating the piston hole with exterior, and an annular projection with front and rear peripheral surfaces partially formed on a peripheral surface of the valve, the cylinder being mounted the outside of the valve and including a plurality of cylinder holes for reciprocating the piston; and a rear cover mounted on the rear of the valve and the cylinder, the piston, the cylinder and the valve having a plurality of chambers and a valve switching chamber defined by making a difference in diameter along a longitudinal direction for providing predetermined annular chambers between inner and outer peripheral surfaces thereof into which the fluid can be introduced, the cylinder including a cylinder block formed with a plurality of fluid passages for inflow/discharge of a working oil.
In contrast to the prior art, the invention makes it possible to reduce the number of components for providing a flow path of the hydraulic pressure, simplify the flow path itself, and lighten weight of the apparatus because working oil acting on the valve properly switches an inflow/a discharge direction of the hydraulic pressure to reciprocate the piston.
In this construction of the invention, the cylinder block is further provided with a high-pressure accumulator and a low-pressure accumulator for compensating oil quantity or preventing pulsation during the piston reciprocation to absorb shock pressure.
Preferably, a plurality of holes of the valve include at least a valve switching chamber penetration hole, a valve low-pressure penetration hole and a valve return penetration hole, a plurality of cylinder holes include at least a cylinder low-pressure penetration hole, a cylinder return penetration hole and a cylinder high-pressure penetration hole, and a plurality of chambers consist of at least a front chamber, a rear chamber and a middle chamber.
In this way, the flow path is automatically switched by piston driving hydraulic pressure only under proper interaction of the above-mentioned holes, which can dispense with separate components or units for switching of the flow path and thus reduce not only the size of the apparatus itself as well as costs thereof.
Accordingly, since separate components, for example, the valve plug or the valve tappet for switching of the valve, the high-complicated multistage passages for high-pressure delivery are unnecessary and the valve need not be larger, it is capable of decreasing the weight and costs of the apparatus resulted from the reduction of the number of components.
The above and other objects, features and advantages of the invention will be apparent from the following detailed description of a preferred embodiment.
BRTBF DgaCRTP'!'TON OF TH8 DR_~~TNr=c The preferred embodiment of the percussion movement apparatus according to the invention will be described in detail in conjunction with the accompanying drawings, in which:
Fig. 1 is a front view showing a percussion movement apparatus in accordance with the present invention;
Fig. 2 is a longitudinal sectional view showing the percussion movement apparatus in accordance with the present invention;
Fig. 3 is an enlarged sectional view showing a valve as a part of the percussion movement apparatus in accordance of the present invention;
Fig. 4 is an enlarged sectional view showing a cylinder as a part of the percussion movement apparatus in accordance of the present invention;
Fig. 5 is an enlarged sectional view showing a rear cover as a part of the percussion movement apparatus in accordance of the present invention;
Figs. 6A to 6C are sectional views showing determinant parts of the present invention on a large scale.
The first feature of the invention is in that the path of high-pressure fluid for descending the piston is to be a minimal path to the cylinder rear chamber. The second feature of the invention is further in that a fluid flow path for valve switching communicates directly with the valve switching chamber without passing through multistage paths by defining the fluid flow path for valve switching by virtue of organic cooperation of the valve and the piston, thereby maximizing efficiency of momentum, and in that the valve surrounds the piston. According to this features of the invention, a percussion movement apparatus having less weight and simpler structure can be provided because the installation space for the separate valve is omitted.
S Fig. 1 and Fig. 2 illustrate a percussion movement apparatus according to the invention in a front view and a longitudinal sectional view, respectively.
Reference numeral "10" designates a main body containing components for creating percussion force. High-pressure and low pressure accumulators 40, 42 for compensating oil quantity or preventing pulsation during reciprocation of a piston to absorb shock pressure are mounted on one side of the main body 10, and internal components, e.g., an inflow port 60 and a discharge port 70 communicating with a cylinder and so on are formed on the other side of thereof.
High-pressure fluid is introduced into interior by way of the inflow port 60, converted to low-pressure fluid and then discharged via the discharge port 70.
A flushing portion 20 is connected to the main body 10 for transmitting compressed air to an end of a shank on its rotation or reciprocation without leakage, and in turn a rotary portion 30 is connected to the flushing portion 20 for increasing torque of a hydraulic motor by predetermined transmission ratio as described below and transmitting the torque to the shank. Reference numeral "80", "100" and "120" designate a hydraulic motor, a shank for transmitting percussion force and torque to a target, and a rear cover, respectively.
Referring to Fig. 2, the main body 10 comprises the high-pressure accumulator 40, the low-pressure accumulator 42, a piston 130, a valve 140 and so forth as internal essential components. The main body 10 further has a cylinder block 12 including a cylinder 150 therein. The cylinder 150 is constructed to receive the piston 130. The valve 140 is installed between the piston 130 and the cylinder 150.
The piston 130 and the valve 140 are organically cooperated with each other, and the cylinder 150 and the rear cover 120 are so constructed that flow paths are opened/closed by movements of the valve 140.
In the rotary portion 30, an upper chuck 32, a lower chuck 34, a driven gear 36 and a driving gear 38 are rotatably engaged with the shank 100.
Power from the hydraulic motor 80 mounted on one side of the main body 10 is transmitted through a coupling shaft 82 to the driving gear 38 that drives the driven gear 36 to rotate the shank 100 as a final output part.
Figs. 3 to 5 illustrate the valve 140, the cylinder 150 and the rear cover 120 as parts of the percussion movement apparatus in accordance of the invention in an enlarged sectional view, respectively.
Referring to Fig. 3, the valve 140 has a substantially cylindrical overall shape, is formed with a piston hole 142 into which the piston 130 is inserted and moved, and is provided with a plurality of holes 143a, 143b and 143c that communicate the piston hole 142 with exterior.
Giving an account of the holes, a first penetration hole 143a as a valve switching chamber penetration hole, a second penetration hole 143b as a valve low-pressure penetration hole and a third penetration hole 143c as a valve return penetration hole are perforated in the valve 140 by turns from the left-handed side of Fig. 3.
On one side of the valve 140, an annular projection 148 protrudes from a periphery of the valve 140 to form a valve front peripheral surface 148a and a valve rear peripheral surface 148b.
Reference numeral "141" and "149" designate a valve upper end surface and a valve lower end surface, respectively.
Referring to Fig. 4, the cylinder 150 is mounted externally to the valve 140 and is provided with a cylinder hole 152 into which the piston 130 and the valve 140 are inserted and reciprocated. A
first and second penetration holes 153 and 154 as a cylinder low-pressure penetration hole, a third penetration hole 154 as a cylinder return penetration hole and a fourth penetration hole 155 as a cylinder high-pressure penetration hole are formed in the cylinder 150 by turns from the left-handed side of Fig. 4 to communicate the cylinder hole 152 with exterior.
Fig. 5 shows the rear cover 120 mounted in the rear of the valve 140 and the cylinder 150. The rear cover 120 has an attachment flange 122 with a plurality of bolt holes 123, and a step surface for being assembled with one end surface of the valve 140.
Figs. 6A to 6C are cross sectional views illustrating determinant parts of the invention on a large scale.
Referring to Fig. 6, a plurality of spaces (annular chambers) are defined between respective inner and outer circumferential surfaces of the piston 130, the valve 140 and the cylinder 150 because the respective circumferential surfaces have different sizes of a diameter in a longitudinal direction. Fluid can be introduced into the spaces. That is, each of front and rear peripheral surfaces 132 and 134 of the piston 130 have a step portion so that a front chamber 136 (a first chamber) and a rear chamber 138 (a second chamber) are formed between each step portions and the inner circumferential surface of the piston 130, respectively.
Furthermore, a valve switching chamber 145 is defined between inner and outer circumferential surfaces of the valve 140 to move the valve 140 forward or backward by being switched over high-pressure or low-pressure state depending upon the condition of connection with the larger diametric-sized front peripheral surface 132 and the smaller diametric-sized middle peripheral surface 133 of the piston 130. A middle chamber 139 (a third chamber) is defined between the middle peripheral surface 133 of the piston 130 and the valve 140.
The valve 140 whose outer diameter is the same as inner diameter of the cylinder 150 comprises lower and upper end surfaces 141 and 149 upon which a high pressure always acts, a front peripheral surface 148a upon which a low pressure always acts, a rear peripheral surface 148b that produces force for moving the valve 140 according to the action of the high/low pressure, a first penetration hole 143 that always communicates with low-pressure passage, and a second penetration hole 144 that connects/disconnects the rear chamber 138 with/from a low-pressure side by the movement of the valve 140.
A rear portion of the piston 130 is so small-sized in diameter that the rear chamber 138 can be defined between the rear portion of the piston 130 and the valve 140. This rear chamber 138 is connected/disconnected with/from a high-pressure side by the movement of the valve 140 in response to creation or release of the pressure.
The cylinder block 12 is formed with two fluid passages 12a and 12b. The fluid passage 12a communicating the valve switching chamber 145 with the inflow port 60 and the fluid passage 12b communicating the middle chamber 139 with the discharge port 70 make it possible to produce high-speed percussion movement of the piston 130.
Described below is the operation that can be done with the use of the percussion movement apparatus according to the invention of the above-described construction with reference to Figs. 6A to 6C.
Fig. 6A illustrates an initial stage of the percussion movement apparatus, that is, positions of the piston 130 and the valve 140 at the end of their descent movements in which high pressure fluid is introduced through the inflow port 60 into the main body 10 and supplied via the fluid passage 12a to the front chamber 136 in the lower part (a left-handed side in Fig. 6A) of the piston 130.
The stage of Fig. 6A is the state that front and rear chambers 136 and 138 are not communicated with exterior, but they are communicated with each other. In this state, pressures of the front and rear chambers 136 and 138 increase to the same extent because the high-pressure fluid is continuously supplied through the inflow port 60 to the chambers 136 and 138.
At this time, the following relationship is established between the valve lower end surface 141 on the side of the front chamber 136 and the valve upper end surface 149 on the side of the rear chamber 138: cross sectional area of the valve lower end surface 141 ) cross sectional area of the valve upper end surface 149.
Depending upon the relationship of the cross sectional areas relationship, hydraulic pressure on the side of the front chamber 136 acting on the valve lower end surface is more powerful so that the valve 140 moves toward the rear chamber 138, namely, the valve 140 rises. This stage is illustrated in Fig. 6B.
If the valve 140 rises to a certain extent, pressures acting on the upper and lower end surfaces 141 and 149 are equal, and low-pressure identically acts on the valve front and rear peripheral surfaces 148a and 148b.
As shown in Fig. 6B, the valve upper end surface 149 begins to block the fourth hole 156 of the cylinder as a high-pressure penetration hole when the valve 140 moves toward a right-handed side (an upper side).
In the fully-risen state of the valve 140, since the second chamber defined by the smaller diametric sized piston, i.e., the rear chamber 138 is disconnected from the fourth hole 156 as the cylinder high-pressure penetration hole and is connected with the third hole as the cylinder low-pressure penetration hole, a high pressure and a low pressure act on the piston front peripheral surface 132 and the piston rear peripheral surface 134, respectively so that the piston 130 can rise due to this pressure difference.
At this time, working oil in the rear chamber 138 is discharged through the third hole 155 into the fluid passage 12b.
If the piston 130 rises to an extent that the piston front periphery surface 132 passed through the valve lower end surface 141 as shown in Fig. 6C, the high-pressure fluid in the piston front chamber 136 acts on the valve rear peripheral surface 148b of the valve switching chamber 145 through the first penetration hole 143a between the piston 130 and the valve 140 to descend the valve 140.
When the piston rear chamber 138 is communicated with the cylinder fourth hole 156 due to the descent of the valve 140, identical high pressures act on the piston front and rear peripheral surfaces 132 and 134, but still the piston 130 moves forward to be positioned as shown in Fig. 6C because cross sectional area of the rear peripheral surface 134 is larger than that of the front peripheral surface 132. Then, the same stroke is repeated as mentioned above.
According to the above-described percussion movement apparatus of the invention, the valve is installed between the piston and the cylinder The valve can automatically switch the inflow/discharge path of the working oil using the working oil for functioning the components of the percussion movement apparatus as it is. Also, the valve can dispense with separate components or units for switching of the flow path, for example, a valve plug, a valve tappet, and etc., for switching of the valve. Also, since high-complicated multistage passages for high-pressure working oil delivery are unnecessary and the valve need not be larger to control the working oil, a possibility of troubling is lowered due to a decrease in the number of components and cost-down results from reduction in the size/weight of the apparatus.
Furthermore, pressure loss is minimized and thus efficiency is maximized in that the length of the fluid passage is minimizes and in that high-pressure working oil is directly supplied into the valve switching chamber and the piston rear chamber. Finally, the apparatus is simplified and lightened by positioning the valve over the piston peripheral surface in a coaxial relation to the piston.
While the invention has been shown and described with reference to the preferred embodiment but is for illustrative purpose only, the invention is limited thereto and it will be easily understood by those skilled in the art that many changes and modifications can readily be made to the invention without departing from the spirit and scope of the invention as defined the appended claims . It is intended to include all such changes and modifications insofar as they come within the spirit and scope of the claims or equivalents thereof.

Claims

1. In a percussion movement apparatus comprising a main body containing at least components for creating percussion force, a piston for reciprocating within a cylinder to discharge high-pressure fluid supplied through an inflow port, a shank connected to an output stage of the piston, and a power generator unit for rotating the shank, the improvement comprising:
a valve installed between said piston and said cylinder, said valve being constructed to open and close a flow path and cooperate with said piston by predetermined movements thereof, said valve having a substantially cylindrical overall shape whose end surfaces which are upper and lower end surfaces thereof with different sectional areas, and also said valve including a longitudinal piston hole with multistage sills, a plurality of holes extending perpendicularly to the piston hole for communicating the piston hole with exterior, and an annular projection with front and rear peripheral surfaces partially formed on a peripheral surface of the valve, said cylinder being mounted on the outside of the valve and including a plurality of cylinder holes for reciprocating the piston; and a rear cover mounted on the rear of said valve and said cylinder, said piston, said cylinder and said valve having a plurality of chambers and a valve switching chamber defined by making a difference in diameter along a longitudinal direction for providing predetermined annular chambers between inner and outer peripheral surfaces thereof into which the fluid can be introduced, and said cylinder including a cylinder block formed with a plurality of fluid passages for inflow or discharge of a working oil.

2. The percussion movement apparatus according to claim 1, wherein said valve further comprises an annular projection on its peripheral surface, and at least a valve switching chamber penetration hole, a valve low-pressure penetration hole and a valve return penetration hole on the side of the valve rear peripheral surface having larger annular area of left- and right-handed annular areas of the projection.

3. The percussion movement apparatus according to claim 2, wherein said piston hole of the valve further comprises a first step sill and a second step sill connected with the valve switching chamber penetration hole for defining the movement of the piston.