JP2006193915A - Counterweight of construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a stock and shorten a delivery period by shortening a curing period when a counterweight is molded by casting. <P>SOLUTION: This counterweight 11 comprises an outer weight 12 on the outside, an inner weight 13 on the inner side, and bolts 14 tightening these weights 12 and 13 to each other. Since the outer weight 12 and the inner weight 13 can be separately molded by casting, thicknesses of these weights 12 and 13 can be reduced. Thus, since the curing period when the weights 12 and 13 are molded by casting is shortened, the quantity of the stock of the weights 12 and 13 can be reduced. Also, by shortening the curing period, the counterweight 11 with excellent paint quality can be prepared in a short delivery period and can be adapted to mass-production. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a counterweight of a construction machine mounted on a hydraulic excavator or the like in order to balance the weight with, for example, a work device.

  In general, a hydraulic excavator as a construction machine is provided with a self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a front-rear side of the upper revolving body that can be raised and lowered. It is roughly constituted by a working device. The upper revolving unit is mounted with a counterweight that is positioned at the rear of the revolving frame that forms the support structure to balance the weight with the work device.

  Here, in recent hydraulic excavators, when the upper swinging body is turned, the counterweight is moved to the front side so that the turning radius becomes smaller. The shape is close to a circle that fits within the width. In this small swivel excavator, the counterweight moves to the front side and approaches the swivel center. Therefore, it is necessary to increase the weight of the counterweight in order to maintain the weight balance with the work device. Moreover, it is necessary to reduce the counterweight in accordance with the downsizing of the upper swing body. For this reason, the counterweight is formed using a casting having a large specific gravity so that a large weight can be obtained in a small installation space. And the counterweight is formed in the crescent moon shape which the outer peripheral side curved in circular arc shape so that a circular upper turning body may be followed (for example, refer patent document 1).

Japanese Patent Laid-Open No. 11-229441

  By the way, since the hydraulic excavator according to the above-described prior art integrally forms the counterweight by casting, the thickness is increased in the case of requiring a large weight, such as the counterweight used in the small swing type hydraulic excavator. Resulting in. When the thickness of the counterweight is increased in this way, the curing period after casting becomes longer, so that there is a problem that many counterweights must be prepared in accordance with the curing period.

  For example, when mass-producing hydraulic excavators, it is necessary to pay the counterweight with a short delivery time. However, if a sufficient curing period is not taken after casting, there is a possibility that pinholes and foaming may occur on the painted surface applied to the counterweight due to the gas flowing out from the inside, and repainting etc. must be performed. There's a problem.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to reduce the inventory period and shorten the delivery time by shortening the curing period when casting the counterweight. It is to provide a counterweight for a construction machine.

  According to the first aspect of the present invention, there is provided a counterweight made of a casting that is mounted to balance the weight of the rear part of the frame of the construction machine. The outer part is formed separately from the outer part and is arranged inside the front surface of the outer part and a fastening member that integrally fastens the outer part and the inner part.

  According to a second aspect of the present invention, the outer appearance portion is provided with a concave step portion located on the inner side, and the inner portion is provided with a convex step portion on which the concave step portion is placed.

  According to the invention of claim 3, the fastening member is constituted by a bolt that penetrates the inner portion and is screwed to the outer appearance portion, and the bolt hole of the outer appearance portion to which the bolt is screwed is a bottomed hole. It is to be formed as.

  According to a fourth aspect of the present invention, the inner portion is provided with a placement portion that is placed on a weight support portion provided at a rear portion of the frame.

  According to the first aspect of the present invention, the counterweight is configured to integrally fasten the external portion exposed to the outside and the inner portion disposed inside the front surface of the external portion by the fastening member. Accordingly, since the outer appearance portion and the inner inner portion can be separately cast, the thickness dimensions of the appearance portion and the inner portion can be kept small. As a result, the curing period when the counterweight is cast-molded can be shortened, so that the quantity of stock can be reduced and the manufacturing cost can be reduced. Moreover, since good coating can be applied in a short period of time after casting, it can be applied to mass production.

  According to the invention of claim 2, by placing the concave step portion provided in the outer portion on the convex step portion of the inner portion, the outer portion and the inner portion can be aligned upward and downward, and the fastening member The fastening operation by can be easily performed. Moreover, since the load of the external part acting on the inner part can be received between the convex step part and the concave step part, it is possible to prevent the shearing load from acting on the fastening member, and durability, reliability, etc. Can be improved.

  According to the third aspect of the present invention, the inner portion and the outer appearance portion can be easily fastened by screwing the front end portion of the bolt penetrating the inner portion into the bolt hole of the outer appearance portion. Moreover, since the bolt hole provided in the external appearance part is formed as a bottomed hole, it can prevent that a bolt hole and a bolt are exposed from this external appearance part, and can improve appearance.

  According to the fourth aspect of the present invention, when the inner portion is placed on the weight support portion provided at the rear portion of the frame, the inner placement portion is placed on the weight support portion. On the other hand, the inner portion can be stably placed.

  Hereinafter, a case where a counterweight of a construction machine according to an embodiment of the present invention is applied to a hydraulic excavator will be described as an example, and will be described in detail with reference to FIGS. 1 to 6.

  In FIG. 1, reference numeral 1 denotes a hydraulic excavator shown as a specific example of a construction machine. The hydraulic excavator 1 includes a self-propelled lower traveling body 2 and an upper revolving body mounted on the lower traveling body 2 so as to be able to swivel. 3 and a work device 4 which is provided on the front side of the upper swing body 3 so as to be able to move up and down and performs excavation work of earth and sand and the like. The upper swing body 3 is generally constituted by a swing frame 5, a cab 9, a building cover 10, a counterweight 11 and the like which will be described later.

  Reference numeral 5 denotes a revolving frame constituting the upper revolving structure 3, and the revolving frame 5 is formed as a support structure. As shown in FIG. 2, the turning frame 5 is roughly constituted by a center frame 6, side frames 7 </ b> A and 7 </ b> B, a protruding beam 8, and the like which will be described later.

  Reference numeral 6 denotes a center frame that constitutes the central portion of the revolving frame 5, and the center frame 6 is erected on a bottom plate 6A formed of a thick steel plate or the like extending in the front and rear directions, and on the bottom plate 6A. The left and right center beams 6B extend forward and rearward at a predetermined interval in the right direction. Further, the working device 4 is attached to the front side of each center beam 6B so as to be able to move up and down. On the other hand, a flange plate 6C is fixed to the upper end edge of each center beam 6B from the middle part in the front and rear directions to the rear end part, whereby the rear part of each center beam 6B projects to the rear side. It is an I-shaped weight support portion 6D. The left and right weight support portions 6D are provided with a placement portion 13K of an inner weight portion 13 constituting a counterweight 11 described later, and are provided with two bolts so as to penetrate upward and downward. An insertion hole 6D1 is provided.

  Reference numerals 7A and 7B denote left and right side frames which are arranged on the left and right sides of the center frame 6 with an interval and extend in the front and rear directions. These left and right side frames 7A and 7B are attached to the distal ends of a plurality of extending beams 8 extending leftward and rightward from the center frame 6.

  On the other hand, 9 is a cab (see FIG. 1) that is mounted on the revolving frame 5 and is located on the left front side of the upper revolving structure 3. , An operation lever, a pedal, a switch (not shown) for traveling, and the like are provided.

  A building cover 10 is provided between the cab 9 and a counterweight 11 described later and provided on the revolving frame 5. The building cover 10 is provided on the left and right side covers 10A (only the left side is shown) extending in the front-rear direction along the side frames 7A and 7B of the revolving frame 5 and on the upper end side of each side cover 10A. The upper cover 10B is generally constituted. The building cover 10 accommodates an engine, a hydraulic pump, a heat exchanger, a tank and the like (all not shown) mounted on the revolving frame 5.

  Next, 11 is a counterweight provided at the rear part of the swing frame 5, and the counterweight 11 balances the weight with the working device 4 attached to the front side of the swing frame 5, as shown in FIG. It is. As shown in FIGS. 2 to 6, the counterweight 11 is roughly constituted by an external weight portion 12, an inner weight portion 13, and a bolt 14 which will be described later.

  Reference numeral 12 denotes an external weight portion as an external portion constituting the outer portion exposed to the outside of the counterweight 11. The appearance weight portion 12 is made of a casting formed by casting, and defines the outer shape of the rear side of the upper swing body 3.

  Here, since the counter weight 11 has the outer appearance weight portion 12 and the inner weight portion 13 formed separately, the outer weight portion 12 reduces the overall thickness to, for example, 200 mm or less. be able to. Thereby, the appearance weight part 12 can shorten the curing period until the whole is cooled after casting and the internal gas is completely exhausted, and can be applied in a short period of time. It should be noted that most of the appearance weight portion 12 only needs to have a thickness dimension of 200 mm or less, and even if a portion exceeds the thickness dimension of 200 mm, it hardly affects the curing period. In addition, there is no problem at all if the portion having a thickness of over 200 mm is difficult to see from the outside.

  As shown in FIGS. 5 and 6, the appearance weight portion 12 is formed in an arc shape so that the center portion in the left and right directions protrudes to the rear side. 12B and the lower surface 12C are arranged at a position where they can be seen from the outside. On the other hand, the front surface 12 </ b> D of the external weight portion 12 is formed in a concave arc shape, and is disposed at a position that cannot be seen from the outside by the building cover 10 and the inner weight portion 13.

  In addition, a concave step 12E is formed in the appearance weight portion 12 by recessing the lower portion of the front surface 12D to the rear side, and the lower side of the concave step portion 12E is a concave surface 12F. Here, the concave step portion 12E rides on the upper side of the convex step portion 13E of the inner weight portion 13 described later. Accordingly, the recessed step 12E and the recessed surface 12F are positioned at a substantially intermediate portion in the left and right directions, and are formed to have a width dimension in which the protruding step 13E of the inner weight portion 13 fits. And the concave step part 12E can align the external weight part 12 and the inner weight part 13 in the up and down direction by placing it on the upper side of the convex step part 13E. Further, since the recessed step portion 12E and the like are formed with a width dimension to which the protruding step portion 13E fits, the appearance weight portion 12 and the inner weight portion 13 can be aligned in the left and right directions.

  Furthermore, for example, four bolt holes 12G are formed in the front surface 12D and the recessed surface 12F of the appearance weight portion 12 with a predetermined interval. Further, as shown in FIG. 3, each bolt hole 12G is formed as a bottomed hole that opens toward the front side, so that a bolt hole 12G and a bolt 14 described later are exposed on the rear surface 12A of the external weight portion 12. Can be prevented.

  Reference numeral 13 denotes an inner weight portion as an inner portion disposed inside the front surface of the external weight portion 12. Since the inner weight portion 13 is formed as a casting that is cast separately from the outer weight portion 12, the overall thickness dimension is reduced (thinned) for the same reason as the outer weight portion 12. Can do. Here, the inner weight portion 13 is almost entirely covered with the building cover 10, the exterior weight portion 12, and the like when mounted on the upper swing body 3. Accordingly, the inner weight portion 13 does not require high coating quality, and the thickness dimension may exceed 200 mm. However, the curing period can be shortened by reducing the thickness dimension.

  As shown in FIGS. 5 and 6, the inner weight portion 13 is formed across the rear surface 13A curved in substantially the same arc shape as the front surface 12D of the appearance weight portion 12, and the left and right ends of the rear surface 13A. A flat front surface 13B, and a crescent-shaped upper surface 13C and lower surface 13D.

  Further, the inner weight portion 13 is formed with a protruding step portion 13E by protruding the lower portion of the rear surface 13A to the rear side, and the lower side of the protruding step portion 13E is a protruding surface 13F. Here, the convex step portion 13E can receive the weight of the external weight portion 12 by placing the concave step portion 12E of the external weight portion 12 on the upper side, and further, the inner weight portion 13 and the external weight portion 12 are connected to each other. Up, down and left, right can be aligned.

  The inner weight portion 13 is provided with four bolt through holes 13G so as to correspond to the four bolt holes 12G of the external weight portion 12. As shown in FIG. 3, these bolt through holes 13G penetrate from the front surface 13B to the rear surface 13A and the protruding surface 13F.

  On the other hand, two U-shaped mounting grooves 13H extending in the forward and rearward directions are provided on the lower side of the inner weight portion 13 with an interval in the left and right directions, and the turning frame 5 is provided in each of the mounting grooves 13H. Each weight support part 6D of the center frame 6 which comprises is fitted. The front surface 13B of the inner weight portion 13 is provided with two forward projecting portions 13J protruding forward from the upper position of the left and right mounting grooves 13H. And the mounting part 13K is comprised by the upper bottom of the attachment groove | channel 13H, and the lower surface of the front protrusion 13J.

  Here, when the counterweight 11 is attached to the weight support portion 6D of the center frame 6, the placement portion 13K is placed on the weight support portion 6D. At this time, the placing portion 13 </ b> K prevents the inner weight portion 13 from falling forward and backward by the forward projecting portion 13 </ b> J, and stably places the inner weight portion 13 on the revolving frame 5. .

  Further, two bolt holes 13L are provided at positions corresponding to the two bolt insertion holes 6D1 provided in the weight support portion 6D in each mounting groove 13H and forward projection 13J of the inner weight portion 13. . The inner weight portion 13 is attached to the rear portion of the revolving frame 5 by screwing a tip of a weight fixing bolt 15 (described later) inserted into the bolt insertion hole 6D1 of the weight support portion 6D from below into the bolt hole 13L. It is fixed.

  Reference numeral 14 denotes four bolts as fastening members for fastening the outer weight portion 12 and the inner weight portion 13. These bolts 14 penetrate the bolt through holes 13G of the inner weight part 13 from the front side, and screw the front end part into the bolt holes 12G of the outer weight part 12, thereby connecting the outer weight part 12 and the inner weight part 13 together. Can be fastened together.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, an operation when the excavator 1 is operated to perform excavation work and the like will be described.

  First, the operator gets on the cab 9 and sits in the driver's seat. By operating the operation lever for traveling in this state, the crawler of the lower traveling body 2 can be driven to move the hydraulic excavator 1 forward or backward. Further, the operator seated in the driver's seat can perform the excavation work of earth and sand, etc. by operating the operation lever for work to move the working device 4 up and down.

  And according to this Embodiment, the external weight part 12 and the inner side weight part 13 which comprise the counterweight 11 are each shape | molded as a separate casting. At this time, since each weight part 12 and 13 is cast-molded separately, each thickness dimension can be restrained small. In particular, since the external weight portion 12 exposed to the outside is formed so that the overall thickness dimension is 200 mm or less, it can be completely cooled to the central portion in a short time after casting, A situation in which the remaining gas flows out can be prevented. Thereby, the curing period after casting can be shortened. And if the curing period of each weight part 12 and 13 passes, a counterweight 11 can be assembled by coating and fastening with each bolt 14 integrally.

  When the counterweight 11 is assembled, the placement portion 13K of the inner weight portion 13 is placed on the weight support portion 6D of the center frame 6 that constitutes the turning frame 5. In this state, the counterweight 11 can be fixed to the rear portion of the swivel frame 5 by inserting the weight fixing bolt 15 into the bolt insertion hole 6D1 of the weight support portion 6D and screwing the tip of the weight fixing bolt 15 into the bolt hole 13L. .

  Thus, according to the present embodiment, the counterweight 11 is configured to be assembled by fastening the outer appearance weight portion 12 and the inner inner weight portion 13 with the bolts 14. Therefore, since the appearance weight portion 12 and the inner weight portion 13 can be separately cast and molded, the thickness dimensions of the weight portions 12 and 13 can be reduced (thinned).

  As a result, since the curing period when the outer weight part 12 and the inner weight part 13 are cast and molded can be shortened, the quantity of the weight parts 12, 13 can be reduced, and the manufacturing cost can be reduced. .

  Moreover, since the external weight portion 12 exposed to the outside is formed so that the overall thickness dimension is 200 mm or less, the internal gas can be removed in a short time after casting. Thereby, the period from casting molding to coating can be shortened, and the painted surface can be finished well. Thereby, since the high quality counterweight 11 can be prepared with a short delivery time, it can respond also to mass production.

  Further, the outer weight portion 12 is provided with a concave step portion 12E, and the inner weight portion 13 is provided with a convex step portion 13E on which the concave step portion 12E is placed. Can be aligned. Thereby, the position of the bolt hole 12G of the external weight portion 12 and the bolt through-hole 13G of the inner weight portion 13 can be adjusted to be prepared, and the fastening operation with the bolt 14 can be easily performed. Moreover, since the load of the appearance weight part 12 which acts on the inner weight part 13 can be received between the convex step part 13E and the concave step part 12E, it can prevent that a shear load acts on the volt | bolt 14, and is durable. The reliability and reliability can be improved.

  On the other hand, since the bolt hole 12G of the external weight portion 12 to which the bolt 14 is screwed is formed as a bottomed hole, the bolt hole 12G and the bolt 14 can be prevented from being exposed from the rear surface 12A of the external weight portion 12. The appearance can be improved.

  Further, since the inner weight portion 13 is provided with a placement portion 13K that is placed on the weight support portion 6D of the center frame 6 constituting the revolving frame 5, the placement portion 13K is placed on the weight support portion 6D. As a result, the inner weight portion 13 (counter weight 11) rattles with respect to the revolving frame 5 and can be stably placed in a state in which positional deviation or the like is prevented.

  In the embodiment, a case where the front protrusion 13J is provided on the front surface 13B of the inner weight portion 13 and the mounting portion 13K is formed by the lower surface of the front protrusion 13J and the upper bottom of the mounting groove 13H is taken as an example. Explained. However, the present invention is not limited to this, and for example, a forward projecting portion may be deleted from the front surface 21B, such as the inner weight portion 21 according to the modification shown in FIG. In this case, the upper bottom of the mounting groove 21H becomes the mounting portion 21J.

  In each embodiment, the counterweight 11 of the crawler excavator 1 has been described as an example as the counterweight of the construction machine. However, the present invention is not limited to this, and can be widely applied to, for example, a counterweight provided in a hydraulic excavator, a hydraulic crane, a wheel loader, or the like provided with a wheel-type lower traveling body.

It is a front view which shows the hydraulic excavator provided with the counterweight by embodiment of this invention. It is the disassembled perspective view which expands and shows in the state which decomposed | disassembled the turning frame and counterweight in FIG. It is a front view which shows the turning frame and counterweight fractured | ruptured in the position of the weight support part of a center frame. It is an external appearance perspective view shown in the state which assembled the counterweight. It is a disassembled perspective view which shows the counterweight in the state decomposed | disassembled into the external weight part, the inner side weight part, and the volt | bolt. FIG. 6 is an exploded plan view showing an appearance weight portion and an inner weight portion in an exploded state. It is the front view seen from the position similar to FIG. 3 which shows the counterweight by the modification of this invention with the turning frame.

Explanation of symbols

1 Excavator (construction machine)
5 Rotating frame (frame)
6 Center frame 6A Bottom plate 6B Center beam 6C Flange plate 6D Weight support 11 Counterweight 12 Appearance weight (appearance)
12A, 13A, 21A Rear surface 12B, 13C, 21C Upper surface 12C, 13D, 21D Lower surface 12D, 13B, 21B Front surface 12E Recessed step portion 12F Recessed concave surface 12G Bolt hole 13, 21 Inner weight portion (inner portion)
13E, 21E Convex step portion 13F, 21F Protruding surface 13G, 21G Bolt through hole 13H, 21H Mounting groove 13J Forward protruding portion 13K, 21J Mounting portion 13L, 21K Bolt hole 14 Bolt (fastening member)

Claims (4)

  A counterweight made of a casting that is mounted to balance the weight of the frame of a construction machine, and has an external part that is exposed to the outside and defines an external shape, and is molded separately from the external part. A counterweight for a construction machine comprising an inner part disposed inside the front surface of an outer appearance part and a fastening member that integrally fastens the outer appearance part and the inner part.   The construction machine counterweight according to claim 1, wherein the outer appearance portion is provided with a concave step portion located on the inner side, and the inner portion is provided with a convex step portion on which the concave step portion is placed.   2. The fastening member is constituted by a bolt that penetrates the inner portion and is screwed to the outer appearance portion, and a bolt hole of the outer appearance portion to which the bolt is screwed is formed as a bottomed hole. Or the counterweight of the construction machine as described in 2.   The counterweight for a construction machine according to claim 1, 2, or 3, wherein the inner portion is provided with a placement portion that is placed on a weight support portion provided at a rear portion of the frame.

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