JP4446471B2 - Construction machine boom and arm connection structure - Google Patents

Description

  The present invention relates to a boom and arm connection structure in a construction machine.

  FIG. 5 shows an example of a working unit of a construction machine. As shown in the figure, the working unit of the construction machine has a boom 6 extending from a vehicle body (not shown), an arm 7 is connected to the tip of the boom 6, and a work tool (bucket 3 in the figure) is attached to the tip of the arm 7. Connected. In this structure, the connecting structure of the boom 6 and the arm 7 is such that the boom nose 60 at the tip of the boom 6 (the pivot support at the tip of the boom) sandwiches the pivot support 70 at the base of the arm 7 and the pin 5 is inserted from the boom nose 60. The arm 7 is pivotally supported.

In general, in construction machinery, the width of the arm 7 body is slightly narrower than the width of the boom 6 body (several centimeters). On the other hand, in the arm 7 , the arm shaft support portion 70 has a structure in which a reinforcing plate or the like is added to the steel plate constituting the main body, so the width of the shaft support portion 70 is slightly wider than the arm 7 body width, It is about the same width as the boom 6 body width (however, there are actually some differences). For this reason, the boom nose 60 that sandwiches the arm shaft support portion 70 protrudes largely outward from the boom 6 body and the arm 7 body.

  By the way, depending on the type of construction machine, the pressure oil tubes 8 are piped on both sides of the boom 6, and in this case, in the part of the boom nose 60 that is the connecting part of the boom 6 and the arm 7, the part 60 is the boom 6. As the main body and the arm 7 protrude outward from the main body, it is necessary to bend the pressure oil tube 8 so that only that portion is offset outward.

  Further, since the pressure oil tube 8 protrudes outward only by the offset portion, there is a high possibility that the pressure oil tube 8 collides with an interference object and is damaged during the operation of the construction machine.

  The present invention was devised in view of the above problems, and prevents the pressure oil tube from causing an offset bending, and also reduces the possibility of the pressure oil tube colliding with an interference object and being damaged. It is an object of the present invention to provide an articulated boom-arm connection structure.

For this reason, the boom-arm connection structure of the construction machine according to the present invention is a connection structure in which a boom nose attached to the tip of the boom and an arm made of a welded cross-section box structure are pivotally supported via pins. The boom nose that forms the pivot support of the boom is formed to be narrower than the width of the boom body, and the pivot support of the arm is formed so as to be able to hold the boom nose , and is substantially the same width or less than the width of the main body. It is formed so that it may become the width | variety of this.

The shaft support in the present application refers to the shaft support of each of the members through which the connecting pins of the boom and the arm are inserted. Therefore, if this pivotal support part is formed at the end part of each main body of the boom or the arm, the end part corresponds, and in particular, the boom nose attached to the tip of the boom corresponds to the pivotal support part of the boom.

In the present invention, the boom nose serving as the pivot support portion of the boom is sandwiched by the pivot support portion of the arm and is pivotally supported by the pin . The width of the shaft support portion of the arm on the side where the boom nose is sandwiched is the width of the connecting portion of both members.

In addition, the boom nose that is a pivotal support portion of the boom is formed to be narrower than the width of the main body, but the pivotal support portion of the arm is formed to have a width substantially equal to or less than the width of the boom main body. . Here, the shaft supporting the arm, had a may be the substantially the same width as the body width, shaft support arms since side sandwiching, the strength, the use of a slight thickness of the steel plate from steel plate of the body only shaft support (This may cause the width of the shaft support portion to be slightly wider by the difference in plate thickness). Therefore, regarding the arm , if the difference between the main body width and the shaft support portion width is about several tens of millimeters, which is about the difference in plate thickness, it is included in the same width. Of course, if there is no problem in strength, the width of the shaft support portion may be equal to or less than the width of the main body.

In the present invention, the boom nose which is the pivotal support portion of the boom is formed to have a width narrower than the width of the boom body. For this reason, it becomes possible to narrow also the width | variety of the axial support part of the arm which clamps the axial support part below to the main body width of a boom . In the present invention, the width of the shaft support of the arm, since the formed to be substantially the same width or less than the width itself of the body width, narrower than the body width of the boom and the arm of the body width less ( However, the arm can be narrowed to a width of approximately the same width (hereinafter the same). That is, the width of the connecting portion between the two members can be equal to or less than the width of the boom and the arm, and the connecting portion can be structured not to protrude outward. For this reason, even if it is a case where a pressure oil tube is piped in the both sides of a boom, it is not necessary to bend an oil pressure tube outward in a connection part. Further, since the pressure oil tube does not protrude outward, the risk of the pressure oil tube colliding with an interference object and being damaged during the operation of the construction machine is reduced.

  As described above, according to the construction of the boom and arm of the construction machine according to the present invention, even when the pressure oil tube is piped on both sides of the boom, the pressure oil tube is outwardly provided at the connection portion. There is no need to bend, the labor required for installing the piping is reduced compared to the conventional structure, and the cost is reduced.

  In addition, since the pressure oil tube does not protrude outward, the risk of the pressure oil tube colliding with an interference object during work on the construction machine is reduced, so that the operator can operate the boom and arm with peace of mind. It will be possible.

  An example of a specific form according to the present invention will be described with reference to FIGS. The present embodiment is an example applied to a connection structure for working parts of a hydraulic excavator, and the working part is composed of a boom 1, an arm 2, and a bucket 3. Reference numeral 4 denotes a pressure oil tube. For the sake of convenience of explanation, the construction of other working parts (for example, a cylinder, a bucket link mechanism, a link pin, etc.) and the construction of the hydraulic excavator other than the working part (upper turning body and lower traveling body) are omitted.

  The pivot support at the tip of the boom 1 is formed by a boom nose 11 having a narrower width than the main body 10 being fixed. In this embodiment, as will be described later, the pivotal support portion of the arm 2 serves as a clamping portion, and the pivotal support portion of the boom 1 serves as a sandwiching portion, and the width of the boom nose 11 main body serves as the later-described arm 2 pivotal support portion. The width is set so as to fit between the side plate end portions 22a and 23a. Further, since the boom nose 11 is sandwiched, as shown in FIG. 3, the pin hole 11a is formed on the distal end side, and the flange 11b is formed on the proximal end portion. For this reason, the boom nose 11 of this embodiment is a casting.

  The arm 2 has a cross-sectional box structure in which an upper plate (not visible in any figure), a bottom plate 21, and both side plates 22, 23 are welded, and the width of the main body (between both side plates 22, 23) is the boom. The width is tens of millimeters narrower than the main body 10 width. The base end part which becomes the pivotal support part of the arm 2 is formed by butt-joining steel plates (hereinafter referred to as side plate end parts 22a and 23a) that are 10 mm thicker than the both side plates 22 and 23 of the main body. A gap is formed between the portions 22a and 23a. The boom nose 11 main body is fitted and held in the gap between the joined side plate end portions 22a and 23a. Since the boom nose 11 is pivotally supported by the pin 5 in the clamped state, each side plate 22a, 23a has a pin hole 22b (however, the pin hole at the side plate end portion 23a is not visible in any figure). It is installed. In addition, as shown in FIG. 2 (b), the joining state between the side plates and the end portions (22 and 22a, 23 and 23a) is the outer surface alignment between the side plate 22 and the end portion 22a on one side. Between the side plate 23 and the end portion 23a on the direction side, the inner surface is aligned for welding work, and the width between the side plate end portions 22a and 23a is slightly larger than the body width due to the difference in thickness between the side plate 23 and the end portion 23a. It is getting wider. However, the plate thickness difference is more than a dozen millimeters, and the arm 2 body and the shaft support portion of the present embodiment are included in the range of substantially the same width as referred to in the present application.

  As described above, in this embodiment, the boom nose 11 main body that is the pivotal support portion of the boom 1 is formed to be narrower than the width of the boom 1 main body, and the boom nose 11 is the side plate end 22a that is the pivotal support portion of the arm 2. 23a, the width between the side plate ends 22a, 23a is almost the same as the width of the arm 2 main body, and the width of the arm 2 main body is slightly narrower than the width of the boom main body 10. A large step is not formed between the connecting portion of both members 1 and 2 and the arm 2, and at least the side plate end portions 22a and 23a of the arm 1, which is the connecting portion, do not protrude outward with respect to the boom 1. It has a structure. Therefore, as shown in FIG. 1, when the pressure oil tubes 4 are piped on both sides of the boom 1, there is no need to bend the pressure oil tubes 4 outward at the connecting portion, and the piping structure is simplified. . For this reason, the labor required for piping is simplified and the cost is low. Since the pressure oil tube 4 does not protrude outward, the possibility of the pressure oil tube 4 colliding with an interference object during work is reduced, and the operator can operate the boom 1, arm 2, and bucket 3 with peace of mind.

  In this embodiment, the base end portion of the arm 2 is used as a support portion on the holding side, and the support portion on the side where the boom nose 11 is held is used. In addition to simply joining the steel plates, the boom nose 11 has a simple structure that becomes a casting, and the formation cost required for the connecting part of both members 1 and 2 is extremely low. It has become.

Note that the present invention is not limited to the present embodiment is Ru naturally der.

The present invention can be applied to any construction machine as long as it has a boom nose and a welded cross-section box structure arm.

It is an example of the form concerning the present invention, and is a schematic diagram of the working part which showed the connection structure of a boom and an arm. In FIG. 1, it is explanatory drawing which extracted only the boom and the arm. (a) is a schematic view of the whole, and (b) is a partial sectional view. It is explanatory drawing which extracted only the boom of FIG. It is the schematic of the working part which showed the connection structure of the conventional boom and arm.

Explanation of symbols

1 Boom
2 arms
3 bucket
4 Pressure oil tube
5 pin
10 Boom body
11 Boom nose
22,23 Arm side plate
22a, 23a Side plate edge

Claims (1)

In a connection structure in which a boom nose attached to the end of the boom and an arm made of a welded cross-section box structure are pivotally supported via a pin, the boom nose that serves as a pivotal support portion of the boom is narrower than the width of the boom body. together to form the shaft support arm, for a construction machine wherein the boom nose is formed so that it can sandwich the, was formed to have a width substantially equal to or less than the width and its body width boom And arm connection structure.

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