US-20260125951-A1 - Hydraulic Hammering Device

US20260125951A1US 20260125951 A1US20260125951 A1US 20260125951A1US-20260125951-A1

Abstract

A hydraulic hammering device includes a dual damper including a pushing piston, a damping piston, a pushing chamber configured to generate a propulsive force in the pushing piston ( 5 ), a damping chamber configured to generate a propulsive force in the damping piston, and a drain circuit provided in constant isolation from the pushing chamber and the damping chamber and configured to return hydraulic fluid leaked from locations of sliding contact of the pistons to a tank. A first throttle is interposed in the drain circuit. Only a check valve configured to, while allowing supply of hydraulic fluid from the high-pressure circuit to the pushing chamber, restrict an outflow of hydraulic fluid in the reverse direction is provided in a pushing passage connecting the pushing chamber and a high-pressure circuit. Only a second throttle is provided in a damping passage connecting the damping chamber and the high-pressure circuit.

Inventors

Toshio Matsuda
Tomohiro Goto
Seiya Onodera

Assignees

FURUKAWA ROCK DRILL CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20231003
Priority Date: 20221005

Claims (4)

1 . A hydraulic hammering device comprising: a transmission member configured to transmit a propulsive force toward a crushing target side to a tool; a hammering mechanism configured to strike a blow on a rear portion of the transmission member; a pushing piston disposed immediately behind the transmission member, the pushing piston having a smaller propulsive force than a propulsive force of a device main body of the hydraulic hammering device; a damping piston positioned behind the pushing piston and disposed to slide reciprocally against the pushing piston in forward and backward directions, the damping piston having a greater propulsive force than the propulsive force of the device main body of the hydraulic hammering device; a pushing chamber configured to generate a propulsive force in the pushing piston; a damping chamber configured to generate a propulsive force in the damping piston; a damper pressure source configured to supply the pushing chamber and the damping chamber with hydraulic fluid by way of a high-pressure circuit; a drain circuit provided in constant isolation from the pushing chamber and the damping chamber and configured to discharge a leakage of hydraulic fluid from a location of sliding contact between the pushing piston and the damping piston to a tank; a first throttle interposed in the drain circuit; a pushing passage connecting the pushing chamber and the high-pressure circuit; and a damping passage connecting the damping chamber and the high-pressure circuit, wherein in a supply path of hydraulic fluid including the high-pressure circuit and the pushing passage, only a check valve configured to, while allowing supply of hydraulic fluid from the damper pressure source to the pushing chamber, restrict an outflow of hydraulic fluid from the pushing chamber to the damper pressure source is provided, and in a supply path of hydraulic fluid including the high-pressure circuit and the damping passage, only a second throttle is provided.
2 . The hydraulic hammering device according to claim 1 , wherein after the hammering mechanism strikes a blow on the transmission member, the pushing piston advances following the transmission member, the transmission member advancing preceding the pushing piston, and when reflected energy propagating from the tool to a device main body of the hydraulic hammering device arrives at the pushing piston, the pushing piston and the damping piston are separated from each other.
3 . The hydraulic hammering device according to claim 1 , wherein after the hammering mechanism strikes a blow on the transmission member, only the pushing piston advances relative to the damping piston that stops at an advancing stroke end, such that the pushing piston follows the transmission member, the transmission member advancing preceding the pushing piston, and before a timing when first reflected energy propagating from the tool to a device main body of the hydraulic hammering device arrives at the pushing piston, the pushing piston comes into contact with a rear portion of the transmission member and presses the transmission member.
4 . The hydraulic hammering device according to claim 2 , wherein after the hammering mechanism strikes a blow on the transmission member, only the pushing piston advances relative to the damping piston that stops at an advancing stroke end, such that the pushing piston follows the transmission member, the transmission member advancing preceding the pushing piston, and before a timing when first reflected energy propagating from the tool to a device main body of the hydraulic hammering device arrives at the pushing piston, the pushing piston comes into contact with a rear portion of the transmission member and presses the transmission member.

Description

TECHNICAL FIELD Embodiments of the present invention relate to a hydraulic hammering device, such as a rock drill and a breaker, for crushing bedrock and the like by delivering blows to a tool, such as a rod and a chisel. BACKGROUND A drilling machine crushes bedrock R, which is a crushing target, by delivering blow energy generated in a hammering mechanism 3 of a rock drill main body 1 to a tool including a shank rod 2, a rod 22, and a bit 21, as illustrated in a basic configuration in FIGS. 1A to 1C. The rock drill main body 1 is constantly provided with a propulsive force toward the bedrock R by a known feed mechanism, and the bit penetrates deep into the bedrock R while crushing the bedrock R and drills a blast hole BH. Not all of the blow energy is consumed for crushing the bedrock R, and a portion of the blow energy bounces back from the bedrock R as reflected energy Er. The reflected energy Er on this occasion is transmitted from the bit 21 to the rock drill main body 1 by way of the rod 22 and the shank rod 2, and the reflected energy causes damage to a constituent device, such as the rock drill main body 1 or the shank rod 2, and also becomes a factor causing reduction in drilling efficiency. Therefore, the applicants have developed a “dual damper” from early on as an effective means to counter the reflected energy Er and have improved the dual damper from day to day (see Patent Publication Nos. JP H09-109064 A and WO 2017/110793). A dual damper 4 includes a pushing piston 5 and a damping piston 6 as major constituent components, and a throttle 90 is provided in a high-pressure circuit 7, and check valves 91 and 92 are provided in a pushing passage 71 and a damping passage 72, respectively, as illustrated in a prior art in FIG. 6. The dual damper 4 achieves at the same time both a “cushioning action” to damp the reflected energy Er and thereby protect the rock drill main body 1 from being damaged and a “pushing action” to stably press the bit 21 against the bedrock R to transmit blow energy to the bedrock without loss, at a high level. Because a detailed configuration of other constituent components and a mechanism of action of the dual damper 4 are described in detail in JP H09-109064 A and WO 2017/110793 (in particular, paragraphs 0070 to 0072 and FIG. 6), description thereof will be omitted herein. As used herein, the term “tool” may be synonymous with the bit (21), and the term “transmission members” may be a term collectively referring to a group of members including the rod (22), a sleeve (23), the shank rod (2), and a bush (12). Note that, although a description is omitted herein, when the hydraulic hammering device is a breaker, the rod (or the chisel) functions as both a “tool” and a “transmission member”. SUMMARY However, there is room for improvement in the dual damper. That is, there have been cases where in a hydraulic hammering device capable of delivering a large number of blows by increasing the number of blows, response speed of the dual damper is insufficient such that the cushioning action and the pushing action are not sufficiently exerted. In addition, there is a case where when an operating condition for the hydraulic hammering device is not properly controlled according to conditions of the bedrock R, and again the cushioning action and the pushing action are not sufficiently exerted. Accordingly, the present invention has been made in view of the problem in a hydraulic hammering device as described above, and an object of the present invention is to provide a hydraulic hammering device that is capable of exerting a cushioning action and a pushing action of a dual damper under various conditions. FIRST EMBODIMENT To achieve the object mentioned above, according to a first embodiment of the invention, there is provided a hydraulic hammering device including: a transmission member configured to transmit a propulsive force toward a crushing target side to a tool; a hammering mechanism configured to strike a blow on a rear portion of the transmission member; a pushing piston disposed immediately behind the transmission member, the pushing piston having a smaller propulsive force than a propulsive force of a device main body of the hydraulic hammering device; a damping piston positioned behind the pushing piston and disposed to slide reciprocally against the pushing piston in forward and backward directions, the damping piston having a greater propulsive force than the propulsive force of the device main body of the hydraulic hammering device; a pushing chamber configured to generate a propulsive force in the pushing piston; a damping chamber configured to generate a propulsive force in the damping piston; a damper pressure source configured to supply the pushing chamber and the damping chamber with hydraulic fluid by way of a high-pressure circuit; a drain circuit provided in constant isolation from the pushing chamber and the damping chamber and configured to discharge a leakage