JP3182810U - Chisel for hydraulic breaker - Google Patents

Abstract

A chisel for a hydraulic breaker is provided that improves the holding power of a chisel of a breaker body and increases the allowable bending stress of the chisel.
In a chisel, a breaker insertion portion 2 to be inserted into a breaker body is positioned at a rear end portion to be hit by a hitting piston in the breaker body and a tip side of the hit portion. A concave portion 25 with which the rod pin 8 engages is formed on the peripheral surface, and a holding portion 22 having a standard diameter that is held by the breaker body, and located at a distal end side of the holding portion and at an opening end of the breaker body, from the holding portion. And a large-diameter portion 24 that has a large diameter and is held by the breaker body.
[Selection] Figure 1

Description

  The present invention relates to a chisel that is attached to a breaker body of a hydraulic breaker, and has a rod shape for crushing an object to be crushed by hitting from the rear end and moving forward and backward.

As a hydraulic breaker attached to a work arm of a work vehicle such as a hydraulic power shovel, there is one described in Patent Document 1. This hydraulic breaker uses a striking piston that moves forward and backward within the breaker body to strike the impacted part at the rear end of the chisel supported by the breaker body, and crushes objects to be crushed, such as rocks and ground, to which the tip of the chisel is applied. To do. The chisel is supported with respect to the breaker body so as to advance and retract in the axial direction by a predetermined dimension.
This chisel has a steel rod shape, and the entire structure consisting of a breaker insertion portion inserted into the breaker body and a portion continuously exposed from the breaker body is the same except for a tip portion that forms a cone or a pyramid. The diameter is made. In addition, the shape of the said front-end | tip part has a various thing according to the property of a to-be-crushed object, and the use of an operation | work.

JP-A-8-323648

  In order to crush the object to be crushed using the chisel, the hitting portion at the rear end of the chisel is hit with a hitting piston in the breaker body. Thereby, the tip of the chisel applied to the object to be crushed is driven into the object to be crushed, a crack is generated in the object to be crushed, the tip of the chisel is further penetrated into the crack to enlarge the crack, and these are repeated as appropriate. Crushing takes place.

However, after the tip of the chisel penetrates into the object to be crushed, the chisel described in Patent Document 1 does not change in diameter toward the rear end, so that the expansion of the crack does not proceed. For this reason, it becomes difficult to penetrate the chisel deeply into the object to be crushed.
Further, due to the impact of the chisel against the object to be crushed and the reaction force, not only the axial impact load but also the radial eccentric load acts between the chisel and the breaker body holding the chisel. For this reason, wear occurs between the chisel and the breaker body, and the holding power of the chisel of the breaker body decreases, so the frequency of replacement of support parts such as bushes that are inside the breaker body and contact the outer peripheral surface of the chisel There is also a problem that becomes large.

Furthermore, when the radial radial load becomes large and an excessive force (so-called “koji”) in the bending direction acts on the chisel, the diameter of the entire chisel is the same as described above. It may make the person worried about bending strength.
In view of this, an object of the present invention is to improve the holding power of the chisel of the breaker body and to improve the allowable bending stress of the chisel.

  A certain aspect of the present invention is a rod-shaped chisel that is mounted on a breaker body of a hydraulic breaker attached to a work arm of a work vehicle, and breaks forward and backward by being hit from the rear end to crush the object to be crushed against the front end. In this case, the breaker insertion portion to be inserted into the breaker body is divided into a rear end hitting portion hit by a hitting piston in the breaker main body and a rod pin on the peripheral surface located on the front end side of the hitting portion. A holding portion having a standard diameter that is formed in a recessed portion to be held and held by the breaker body, and is located on the distal end side of the holding portion and at the opening end of the breaker body, has a larger diameter than the holding portion, and is held by the breaker body And a large diameter portion.

Here, although the holding part has a standard diameter, this standard diameter means a standard chisel diameter for determining the specifications of the chisel and the breaker body to which the chisel is to be attached.
In this embodiment, the chisel is supported in the breaker body at two locations, the standard diameter holding portion and the larger diameter portion. For this reason, even if the radial load applied to the chisel causes an abrasion between the open end of the breaker body and the chisel, the chisel diameter is larger than the standard diameter at this position. Since the load per unit area is smaller than in the case of the standard diameter and the wear action is also reduced, it is possible to suppress the deterioration of the supporting parts such as the bush that the chisel contacts.

Bending stress increases because the portion supported by the open end of the breaker body has a large diameter even if excessive force (so-called “koji”) in the direction of bending the chisel acts on the chisel due to the unbalanced load. Therefore, it can sufficiently withstand the “squeeze”.
The chisel includes a tapered portion that is exposed from the breaker body on the distal end side of the large diameter portion in the breaker insertion portion and gradually decreases in diameter toward the distal end, and at a steep angle toward the distal end on the distal end side of the tapered portion. It is good to provide the front-end | tip part which makes the cone or pyramid in which a diameter becomes small.
Thereby, since the diameter of the chisel gradually increases toward the rear end side on the rear end side with respect to the chisel tip, the chisel is further penetrated into the object to be crushed to advance the crack. be able to.

Further, since the holding portion and the large-diameter portion are continuously connected by a short taper portion, a smooth step in the axial direction of the chisel is formed without forming a step portion due to a difference in diameter between the holding portion and the large-diameter portion. Change in diameter can be realized.
Further, between the holding portion and the large diameter portion and the breaker body, the holding portion and the large diameter portion are provided with bushes respectively held by the breaker body, and the inner diameter of the bush holding the large diameter portion is set. The inner diameter of the bush holding the holding portion may be larger. Because the inner diameter of the bush that supports the large-diameter portion is increased in this way, it is possible to form the large-diameter portion in the chisel simply by changing the bush that is a replaceable part without changing the dimensions of the breaker body. become.

  According to this device, the holding power of the chisel of the breaker body can be improved, and the allowable bending stress of the chisel can be improved.

The embodiment of this invention is shown, (a) is a front view, (b) is a side view, (c) is a top view, (d) is a bottom view. Explanatory drawing of the state which mounted | wore the breaker main body with the chisel of FIG. Explanatory drawing which shows the state which is crushing the ground as a to-be-crushed object using the chisel of FIG.

FIG. 1 is a view of a chisel 1 showing an embodiment of the present invention. The chisel 1 is a chisel that is formed as an integral rod, and includes a breaker insertion portion 2 on the rear end side, and the breaker insertion portion. 2, a tapered portion 3 continuing to the distal end of the tapered portion 3, a small diameter portion 4 continuing to the distal end of the tapered portion 3, and a distal end portion 5 continuing to the distal end of the small diameter portion 4.
The breaker insertion portion 2 is a portion that is inserted into the breaker body 6 shown in FIG. 2, a rear end hit portion 21 that is hit by the hit piston 7 in the breaker body 6, and the hit portion 21. The holding portion 22 having a standard diameter continuous to the distal end side of the first portion, a short taper portion 23 continuing to the distal end side of the holding portion 22, and a large diameter portion 24 continuing to the distal end side of the short tapered portion 23.

  The holding portion 22 is a portion that is held by the breaker body 6 with a standard diameter, and the standard diameter is the diameter of the chisel 1 that is a standard for determining the specifications of the chisel 1 and the breaker body 6 to which the chisel 1 is mounted. Say. Therefore, for a chisel having a certain standard diameter, a breaker body having a size suitable for the chisel having the standard diameter is prepared. The holding portion 22 has the same diameter in the axial direction, and a recess 25 is formed on the peripheral surface to engage the rod pin 8 in the breaker body 6. The concave portion 25 is cut at positions facing the opposite sides of the peripheral surface of the holding portion 22, and each bottom surface has two parallel planes. The rod pin 8 of the breaker body 6 is engaged with the recess 25 to restrict the chisel 1 to advance and retract in the axial direction within the range of the length of the recess 25.

The short taper portion 23 is a continuous portion between the large-diameter portion 24 on the tip side and the holding portion 22, and a step portion due to a difference in diameter is formed between the holding portion 22 and the large-diameter portion 24. Thus, the smooth diameter change of the chisel 1 is realized.
The large diameter portion 24 has the largest diameter in the chisel 1, and the diameter thereof is the same in the axial direction of the large diameter portion, and an intermediate position in the axial direction is at the opening end of the breaker body 6. Therefore, the chisel 1 is supported by the breaker body 6 not only at the holding portion 22 but also at the large-diameter portion 24 located inside the breaker body 6. The large diameter portion 24 is supported from the outside by a bush 9 mounted inside the open end of the breaker body 6. The bush 9 is detachably attached to the breaker body 6 and has an outer diameter that matches the inner diameter of the breaker body 6 to which the bush 9 is attached and an inner diameter that matches the outer diameter of the large diameter portion 24 of the chisel 1. The large diameter portion 24 is supported by the breaker body 9 through the bush 9.

  The holding part 22 is supported by the breaker body 6 by the bush 11 fitted to the holding part 22. The bush 11 has an inner diameter that matches the outer diameter (standard diameter) of the holding portion 22, and is smaller than the inner diameter of the bush 9.

  The tip 5 forms a quadrangular pyramid, pierces the object to be crushed, creates a crack, and spreads the crack. Therefore, since the tip shape and angle are determined according to conditions such as the type and properties of the object to be crushed, it is possible to use a cone instead of a pyramid. The diameter of the tip 5 is the same as that of the conventional one, a short small diameter portion 4 is provided on the rear end side, and the tapered portion 3 is provided between the small diameter portion 4 and the large diameter portion 24. Since the tapered portion 3 is located between the large diameter portion 24 and the small diameter portion 4, the large diameter portion 24 and the small diameter portion 4 are connected by forming a taper having a small diameter on the front end side and a large diameter on the rear end side. It is out. For this reason, it sets so that a diameter may become large and a crack may be expanded, so that the chisel 1 may penetrate deeply into a to-be-crushed object, without forming a level | step difference between both 24,4.

  As described above, the chisel 1 is formed with the large diameter portion 24 having a diameter larger than the diameter of the holding portion 22 which is a standard diameter, and the large diameter portion 24 is also supported by the breaker body 6. Is one of the features. Further, since the diameter of the tip portion 5 is the same as that of the conventional one while the diameter of the large diameter portion 24 is increased, the taper portion 3 between them forms a taper with the tip end having a small diameter. One of the features of the chisel 1 is that the tapered portion 3 is formed at a portion exposed from the breaker body 6, that is, at a portion penetrating the object to be crushed.

As shown in FIG. 2, the breaker body 6 includes a front head 61 to which the chisel 1 is mounted, a cylinder 62 that follows the front head 61, and a back head 63 that covers the rear end of the cylinder 62. Inside the breaker body 6, a striking piston 7 for striking the chisel 1 from the rear end is inserted so as to be able to advance and retreat, and on the outside, a hydraulic pressure switching valve 10 for moving the striking piston 7 forward and backward is disposed.
As shown in FIG. 3, the hydraulic breaker including the breaker body 6 is attached to the distal end of a work arm 13 of a hydraulic power shovel 12 constituting a work vehicle via a bracket 14 and is controlled by a cockpit of the hydraulic power shovel 12. It is like that.

  Thus, according to the chisel 1 of this embodiment, the hitting portion 21 is repeatedly hit by the hitting piston 7 with the tip 5 applied to the object to be crushed, so that the hitting force is the tip 5 of the chisel 1. Is transmitted to the object to be crushed and a crack is generated in the object to be crushed by the tip 5. By continuing the hitting, the tip 5 bites into the crack and the crack expands, and when the hitting is continued even after the entire tip 5 has penetrated into the crack, the tapered portion continues to the small diameter portion 4 of the chisel 1. 3 also breaks into the crack. Then, since the diameter of the taper part 3 which enters a crack becomes large gradually, since a crack is further expanded by the taper part 3, a to-be-crushed object can be crushed effectively, and workability | operativity improves.

  An uneven load in the radial direction may be input from the object to be crushed to the chisel 1 by the crushing operation. This unbalanced load causes the wear between the bush 9 at the open end of the breaker body 1 and the chisel 1. However, since the chisel 1 is supported in the breaker body 6 at two locations, the holding portion 22 having a standard diameter and the large diameter portion 24 having a larger diameter, the bush 9 has a large diameter portion having a diameter larger than the standard diameter. 24 touches. Thereby, in the bush 9, the large diameter portion 24, and the contact portion, the load per unit area is smaller than that in the case where the chisel 1 in contact with the bush 9 has a standard diameter, so the wear action is also reduced and the wear amount of the bush 9 is small. Thus, the frequency of replacement decreases.

Further, as described above, since the load per unit area is small in the bush 9, the large diameter portion 24, and the contact portion, the holding force of the chisel 1 in the breaker body 6 is improved.
Furthermore, even if a force (so-called “koji”) in the direction of bending the chisel 1 acts excessively due to the unbalanced load, the portion supported by the bush 9 at the opening end of the breaker body 6 becomes the large diameter portion 24. Therefore, the bending stress is increased. For this reason, it is possible to sufficiently withstand the “squeeze” and to prevent the chisel 1 from being bent or broken.

  As described above, the chisel 1 of this embodiment is mounted on the breaker body 6 with a large diameter portion 24 larger than the standard diameter holding portion 22. It is only necessary to change the bush 9 inside the open end so that the inner diameter matches the large diameter portion 24. Since the bush 9 is a consumable item to be replaced due to wear, it is not necessary to change other parts of the hydraulic breaker or the work vehicle by simply replacing the bush 9 with an expanded inner diameter so as to be adapted to the large diameter portion 24. The chisel 1 of this embodiment can be used as it is.

DESCRIPTION OF SYMBOLS 1 Chisel 2 Breaker insertion part 21 Struck part 22 Holding part 23 Short taper part 24 Large diameter part 3 Taper part 4 Small diameter part 5 Tip part 6 Breaker main body 7 Impact piston 8 Rod pin 9 Bush 10 Switching valve 11 Bush

Claims (4)

In a rod-shaped chisel that is attached to a breaker body of a hydraulic breaker attached to a work arm of a work vehicle, and breaks up and down by hitting from the rear end and crushes the object to be crushed against the tip.
The breaker insertion portion to be inserted into the breaker body is located at the rear end portion to be hit by the hitting piston in the breaker body and the front end side of the hit portion, and the rod pin is engaged with the peripheral surface. A holding portion having a standard diameter that is formed in a recess and is held by the breaker body, and a large diameter that is positioned on the distal end side of the holding portion and is at the opening end of the breaker body, has a larger diameter than the holding portion, and is held by the breaker body. A chisel for a hydraulic breaker characterized by comprising a diameter portion.   A cone that has a tapered portion that is exposed from the breaker body and gradually decreases in diameter toward the distal end on the distal end side of the large diameter portion in the breaker insertion portion, and has a diameter that decreases at a steep angle toward the distal end on the distal end side of the tapered portion. Or the tip part which makes | forms a pyramid was provided, The chisel for hydraulic breakers of Claim 1 characterized by the above-mentioned.   The chisel for a hydraulic breaker according to claim 1 or 2, wherein the holding portion and the large-diameter portion are continuous by a short taper portion. Between the holding portion and the large diameter portion and the breaker body, the holding portion and the large diameter portion are interposed with bushes respectively held by the breaker body, and the inner diameter of the bush holding the large diameter portion is held. The hydraulic breaker chisel according to any one of claims 1 to 3, wherein the diameter is larger than the inner diameter of the bush holding the portion.

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