JP2005289546A - Boom telescopic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an increase in diameter of a cylinder with regard to a boom telescopic device. <P>SOLUTION: The boom telescopic device has a multi-stage cylinder device 10 wherein a plurality of stages of cylinders are connected in a length direction of the boom as an expansion driving source of a telescopic boom 4. In the telescopic boom 4, a base end side of the multi-stage cylinder device 10 is connected to a base end part of the boom, and the tip end part of the multi-stage cylinder device 10 is connected to the tip end part of the boom. The multi-stage cylinder device 10 is divided into two cylinder units 11, 51, both of which have a plurality of stages of structure with a plurality of cylinder tubes and are inversely connected to each other. First stage cylinder tubes 12, 52 connected to each other are arranged in parallel with a cylinder diameter direction, and external communication piping 42 for making expansion compression chambers of the first stage cylinder tubes 12, 52 communicate with each other is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a boom extender for extending and retracting an extendable boom mounted on a crane or the like.

2. Description of the Related Art Conventionally, as a telescopic device for a telescopic boom, a so-called multistage cylinder is known. As disclosed in Patent Document 1 below, this multistage cylinder is a cylinder in which a cylinder as a piston is telescopically stored in a cylinder, and further, a cylinder as a piston is stored in this cylinder, and this is repeated. Are provided in a plurality of stages. In the device described in this document, the base end portion of the outermost cylinder is coupled to the base end portion of the telescopic boom, while the distal end portion of the innermost cylinder is coupled to the distal end portion of the telescopic boom. Accordingly, the telescopic boom is expanded by extending the multistage cylinder, while the telescopic boom is contracted by contracting the multistage cylinder.
JP-A-8-34595

  By the way, in the multi-stage configuration in which the cylinders are sequentially telescopically stored in one cylinder as in Patent Document 1, the outermost cylinder outer diameter must be made very large correspondingly. Therefore, there is a problem that an increase in size of the apparatus cannot be avoided. Moreover, not only does the weight increase with the increase in size, but also the problem arises that the amount of pressure oil required increases as the cylinder capacity increases. Furthermore, when the outer diameter of the cylinder becomes large, there is a possibility that it may be difficult to mount on a boom having a vertically long cross section, which tends to be employed in a long telescopic boom.

  Therefore, the present invention has been made in view of such points, and an object of the present invention is to suppress an increase in the cylinder diameter even when the cylinder is configured in multiple stages.

  In order to achieve the above object, a boom telescopic device according to the present invention includes a multistage cylinder device in which a plurality of cylinders in the boom length direction are coupled as at least an extension drive source of the telescopic boom. The base end side of the multistage cylinder device is connected to the boom base end portion, and the tip end portion is connected to the boom top end portion. The multistage cylinder device is divided into a plurality of cylinder units, and at least one of the cylinder units adjacent to each other. The cylinder unit has a multistage structure including a plurality of cylinder tubes, and both cylinder units adjacent to each other are coupled in opposite directions, and the outermost cylinder tubes are coupled to each other. These cylinder tubes are aligned with each other in the cylinder radial direction at the unit connection. Are arranged, the external communication pipe communicating is provided a decompression pressure chamber between in the outermost cylinder tube are coupled to each other.

  In this boom extender, since the multistage cylinder device is divided into a plurality of cylinder units, it is possible to suppress an increase in the diameter of the cylinder in each cylinder unit while maintaining the number of stages as the entire extender. . In other words, since the boom telescopic device is configured to be divided into a plurality of cylinder units, the number of stages in each cylinder unit is different from that in the conventional configuration in which only one cylinder unit is provided and the number of stages is increased. The number of stages can be reduced. As a result, a cylinder having a smaller diameter than the conventional outermost cylinder can be used as the cylinder of each cylinder unit. For this reason, since the thing with a small cylinder diameter can be used for each cylinder unit, it can suppress that an apparatus enlarges and can reduce the amount of pressurized oil as a whole. In addition, since an external communication pipe that communicates the pressure chambers for extension in the outermost cylinder tubes coupled to each other is provided, the pressure chambers can be communicated even in a configuration divided into a plurality of cylinder units. It is possible to prevent the piping structure from becoming complicated. Moreover, both cylinder units can be extended only by supplying pressure oil to one cylinder unit.

  In the boom telescopic device, each cylinder tube in the multi-stage cylinder device configured as a telescopic boom telescopic drive source includes the expansion pressure chamber for expanding the cylinder unit and the contraction for contracting the cylinder unit. If the contracting external communication pipe is provided to communicate with the contracting pressure chambers in the outermost cylinder tube coupled to each other, the multistage cylinder device is connected to the expansion pressure source. Even when configured as described above, it is possible to prevent the piping structure for communicating the respective pressure chambers for contraction from becoming complicated. Moreover, both cylinder units can be expanded and contracted only by supplying pressure oil to one cylinder unit.

  Further, in the cylinder unit having the multi-stage structure, a length-adjustable expansion / contraction pipe is provided to connect the contraction pressure chamber in the outermost cylinder tube and the contraction pressure chamber in the inner cylinder tube. With this configuration, even if the inner cylinder tube is displaced relative to the outermost cylinder tube, the expansion pipe can absorb the relative displacement of the both contraction oil chambers, and the communication between the two pressure chambers can be absorbed. A state can be secured.

  Further, the expansion and contraction pipe is arranged in a posture extending in the extension and contraction direction of the multistage cylinder device, and is fixed to the outermost cylinder tube and communicated with the contraction pressure chamber; If it is configured to include an inner cylinder fixed to the cylinder tube and communicated with the pressure chamber for contraction and movably inserted into the outer cylinder, the sealing performance of the expansion pipe on which high pressure acts It is possible to make the length adjustable while securing the above.

  The expansion pipe may be provided in each cylinder unit coupled to each other, and the contracting external communication pipe may be connected to the outer cylinders of both cylinder units.

  The telescopic pipe has an outer cylindrical body, a first inner cylindrical body, and a second inner cylindrical body and is shared by two adjacent cylinder units, and the outer cylindrical body is the outermost cylinder tube. Is connected to the pressure chamber for contraction in the outermost cylinder tube, and one end of the first inner cylinder is fixed to the inner cylinder tube in one cylinder unit and communicated with the pressure chamber for contraction. The other end is fitted and inserted into the outer cylinder so as to be movable forward and backward, the second inner cylinder has a diameter different from that of the first inner cylinder, and one end is fixed to the inner cylinder tube of the other cylinder unit. If the configuration is such that it is communicated with the pressure chamber for contraction and the other end is fitted and inserted into the outer cylinder so as to be able to move forward and backward, the configuration can be made compact and the number of parts can be reduced.

  As described above, according to the present invention, the pressure chamber for extension in the outermost cylinder tube which is divided into a plurality of cylinder units and at least one of the adjacent cylinder units has a multistage structure and is coupled to each other. Since the external communication pipes that communicate with each other are provided, it is possible to suppress an increase in the cylinder diameter and to prevent the piping structure from becoming complicated. Thereby, since the width dimension of an expansion-contraction boom can be made small, the same expansion-contraction function can be comprised with a cross-sectional area smaller than before.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

Embodiment 1
1st Embodiment applies this invention to the boom expansion-contraction apparatus for extending the expansion-contraction boom 4 mounted in the self-propelled crane vehicle 2 as shown in FIG. The crane 2 includes a lower traveling body 6 that can travel on the road. The lower traveling body 6 has an upper revolving body 7 supported at a middle part in the front-rear direction via a ring-shaped bearing (not shown) so as to be rotatable about a vertical axis. A cab 8 and a swing frame 9 are installed on the upper swing body 7, and the telescopic boom 4 is supported by the swing frame 9 via a horizontal boom foot pin P so that it can be raised and lowered. The cylinder 19 is driven in the undulation direction by expansion and contraction.

  The telescopic boom 4 has, for example, a hollow vertically long rectangular cross section, and as shown schematically in FIG. 2, a plurality of boom bodies 4a, 4b, 4c are telescopically fitted and configured to be telescopic. Yes. FIG. 2 shows a state where the telescopic boom 4 is extended. As shown in FIG. 3, the boom extender includes a multistage cylinder device 10 as an extension drive source for the extendable boom 4. The multi-stage cylinder device 10 has a structure in which a plurality of stages of cylinders are coupled in the boom length direction, and is disposed inside the telescopic boom 4.

  When the telescopic boom 4 in the contracted state is extended, the multistage cylinder device 10 is extended by introducing pressure oil. The telescopic boom 4 is provided with a rope winder (not shown). By winding a wire rope attached to the rope winder, the multistage cylinder device 10 is contracted to contract the telescopic boom 4. It is like that.

  The multi-stage cylinder device 10 is divided into two cylinder units 11 and 51, and both the cylinder units 11 and 51 have substantially the same configuration and are arranged in opposite directions. The figure shows the multistage cylinder device 10 in a state where the telescopic boom 4 is viewed from the side. The base end 1 of the telescopic boom 4 is located on the right side of the figure, and the distal end of the telescopic boom 4 is located on the left side of the figure. The part (not shown) is located.

  In the first embodiment, each of the cylinder units 11 and 51 is constituted by a two-stage single-acting hydraulic cylinder. That is, in this embodiment, both cylinder units 11 and 51 have a multistage structure. Each cylinder unit 11, 51 includes a first stage cylinder tube 12, 52, a second stage cylinder tube 22, 62 stored telescopically as a piston in the first stage cylinder tube 12, 52, The stage cylinder tubes 22 and 62 include third stage cylinders 32 and 72 that are telescopically housed as pistons. The first-stage cylinder tubes 12 and 52 constitute the outermost cylinder tube in the cylinder units 11 and 51, respectively.

  In the proximal cylinder unit 11 disposed on the upper side in FIG. 3, the first stage cylinder tube 12 is disposed in such a posture that the second stage cylinder tube 22 is fitted to the right end portion thereof. In the front end side cylinder unit 51 disposed on the lower side of the first-stage cylinder tube 52, the first-stage cylinder tube 52 is disposed in such a posture that the second-stage cylinder tube 62 is fitted to the left end portion thereof. The first stage cylinder tubes 12 and 52 are connected to each other by the bracket 40 in a state where they are arranged in the cylinder radial direction, that is, in a direction orthogonal to the axial direction. The vertical direction in the figure is the length direction of the longitudinal section of the telescopic boom 4, and both first stage cylinder tubes 12 and 52 are arranged side by side in this direction. That is, both cylinder units 11 and 51 that are adjacent to each other are coupled in opposite directions, and the first cylinder tubes 12 and 52 that are the outermost cylinder tubes are coupled to each other. These cylinder tubes 12 and 52 are arranged side by side in the cylinder radial direction.

  In both cylinder units 11 and 51, the second-stage cylinder tubes 22 and 62 can slide while maintaining a liquid-tight state with respect to the inner peripheral surfaces of the body portions 12b and 52b of the first-stage cylinder tubes 12 and 52, respectively. The bottom portions 22a and 62a of the second-stage cylinder tubes 22 and 62 are formed in a thick flat plate shape. The bottom portions 22a and 62a of the second stage cylinder tubes 22 and 62 are provided with communication holes 24 and 64 penetrating in the axial direction. On the other hand, the third stage cylinders 32 and 72 are slidable while maintaining a liquid-tight state with respect to the inner peripheral surfaces of the body parts 22b and 62b of the second stage cylinder tubes 22 and 62.

  In the proximal end side cylinder unit 11, the distal end portion of the third stage cylinder 32 protruding outward from the second stage cylinder tube 22 is pin-coupled to the proximal end portion 1 of the telescopic boom 4. On the other hand, in the distal end side cylinder unit 51, the distal end portion of the third stage cylinder 72 projecting outward from the second stage cylinder tube 62 is pin-coupled to the distal end portion of the telescopic boom 4 although not shown. . That is, only the base end portion and the distal end portion of the multistage cylinder device 10 are coupled to the telescopic boom 4, and are not coupled to the telescopic boom 4 at an intermediate portion thereof. In FIG. 3, reference numerals 37 and 77 denote pin holes.

  In the base end side cylinder unit 11, the third stage cylinder 32 is configured to be solid, and an oil passage 38 is formed through the inside thereof in the axial direction. One end of the oil passage 38 is connected to the oil supply / discharge pipe 3 provided at the base end portion 1 of the telescopic boom 4, and the other end opens into the second-stage cylinder tube 22. The oil supply / discharge pipe 3 is configured such that pressure oil is supplied from a hydraulic pump (not shown) using an engine (not shown) as a drive source via a switching valve (not shown).

  In both cylinder units 11 and 51, in the second-stage cylinder tubes 22 and 62, the space between the bottom portions 22a and 62a of the second-stage cylinder tubes 22 and 62 and the third-stage cylinders 32 and 72 is 66, and in the first stage cylinder tubes 12 and 52, the pressure between the bottom parts 12a and 52a of the first stage cylinder tubes 12 and 52 and the bottom parts 22a and 62a of the second stage cylinder tubes 22 and 62 is extended. Chambers 16 and 66 are formed.

  On the other hand, in the distal end side cylinder unit 51, unlike the proximal end side cylinder unit 51, the oil passage 38 of the third stage cylinder 72 is not provided. The other configuration is the same as that of the base end side cylinder unit 11.

  This boom telescopic device is provided with an external communication pipe 42 that communicates the expansion pressure chambers 16 and 56 of both first-stage cylinder tubes 12 and 52. The external communication pipe 42 is constituted by a pipe disposed outside the first stage cylinder tubes 12 and 52. One end of the external communication pipe 42 is connected to the bottom portion 12 a of the first-stage cylinder tube 12 of the proximal-side cylinder unit 11 or the trunk portion 12 b in the vicinity thereof, and the other end is connected to the first-stage cylinder of the distal-end cylinder unit 51. The tube 52 is connected to the bottom 52a or the trunk 52b in the vicinity thereof.

  Next, the operation of the boom extender according to the first embodiment will be described. When the telescopic boom 4 is contracted as shown in FIG. 4, when the hydraulic pump is driven when the telescopic boom 4 is extended, the pressure oil passes through the oil supply / discharge pipe 3 as shown by arrows in FIG. It is supplied to the end side cylinder unit 11. This pressure oil is introduced into the expansion pressure chamber 26 of the second-stage cylinder tube 22 through the oil passage 38, thereby extending the third-stage cylinder 32 with respect to the second-stage cylinder tube 22. At this time, since the third-stage cylinder 32 is fixed, the second-stage cylinder tube 22 is moving in the boom tip direction. A part of the pressure oil introduced into the extension pressure chamber 26 of the second-stage cylinder tube 22 is introduced into the extension pressure chamber 16 of the first-stage cylinder tube 12 through the communication hole 24, thereby The second stage cylinder tube 22 is extended with respect to the stage cylinder tube 12. At this time, the first stage cylinder tube 12 of the proximal end side cylinder unit 11 and the first stage cylinder tube 12 of the distal end side cylinder unit 11 are integrated with each other toward the distal end portion of the telescopic boom 4 (left direction in FIG. 3). Move towards.

  Further, a part of the pressure oil introduced into the extension pressure chamber 16 of the first stage cylinder tube 12 of the base end side cylinder unit 11 passes through the external communication pipe 42 to the first stage cylinder tube 52 of the distal end side cylinder unit 51. Introduced into the extension pressure chamber 56, the second stage cylinder tube 62 is extended with respect to the first stage cylinder tube 52. A part of the pressure oil in the extension pressure chamber 56 is introduced into the extension pressure chamber 66 of the second-stage cylinder tube 62 through the communication hole 64, and the third-stage cylinder with respect to the second-stage cylinder tube 62. 72 is extended. Thereby, the front-end | tip part of the telescopic boom 4 couple | bonded with the front-end | tip part of the 3rd stage cylinder 72 moves, and the telescopic boom 4 expand | extends. At this time, both the first stage cylinder tubes 12 and 52 and the second stage cylinder tubes 22 and 62 of the multistage cylinder device 10 move in the axial direction without being restrained by the boom bodies.

  On the other hand, in order to contract the telescopic boom 4, the wire rope is wound up by a winder and the pressure oil is led out from the boom telescopic device through the oil supply / discharge pipe 3, so that the pressure in the direction opposite to the arrow shown in FIG. Let the oil flow. As a result, the pressure oil in each of the extension pressure chambers 66, 56, 26, 16 flows toward the oil supply / discharge pipe 3 to contract the multistage cylinder device 10, and the telescopic boom 4 contracts.

  Next, the effect by the boom expansion-contraction apparatus of the expansion-contraction boom 4 which concerns on this Embodiment 1 is demonstrated.

  In this Embodiment 1, since it divides | segments into the two cylinder units 11 and 51, it suppresses that a cylinder becomes large in each cylinder unit 11 and 51, maintaining the stage number as the whole boom expansion-contraction apparatus. be able to. That is, the number of stages of each of the cylinder units 11 and 51 can be reduced as compared with a configuration in which one cylinder unit is provided and is multistaged. As a result, a cylinder having a smaller diameter than the conventional outermost cylinder can be used as the first-stage cylinder tubes 12 and 52 of the cylinder units 11 and 51. For this reason, since the thing with a small cylinder diameter can be used for each cylinder unit 11 and 51, it can suppress that an apparatus enlarges and can reduce the amount of pressurized oil as a whole. Moreover, since the external communication pipes 42 are provided to communicate the expansion pressure chambers 16 and 56 of the first-stage cylinder tubes 12 and 52 coupled to each other, the structure is divided into a plurality of cylinder units 11 and 51. Also, it is possible to prevent the piping structure for supplying the pressure oil to the pressure chambers 16 and 56 from becoming complicated. Moreover, both cylinder units 11 and 51 can be extended only by supplying pressure oil to one cylinder unit 11 and 51.

  Further, in the multistage cylinder device 10 according to the first embodiment, only the distal ends of the third stage cylinders 32 and 72 of the cylinder units 11 and 51, that is, the distal ends of the telescopic booms 4 at only one place in each cylinder unit 11 and 51, respectively. It is set as the structure joined to the part or the base end part 3. FIG. In other words, the first stage cylinder tubes 12 and 52 and the second cylinder tubes 22 and 62 of the cylinder units 11 and 51 are not coupled to the telescopic boom 4. For this reason, even if the first stage cylinder tubes 12 and 52 and the second stage cylinder tubes 22 and 62 move in the extension direction by the extension operation of the cylinder units 11 and 51, the first stage cylinder tubes 12 and 52 and the second stage cylinder tubes The stage cylinder tubes 22 and 62 can be moved without being restricted by the extension operation of the telescopic boom 4. Accordingly, it is possible to employ the cylinder units 11 and 51 having the first-stage cylinder tubes 12 and 52 and the second-stage cylinder tubes 22 and 62 having a length different from the length of each stage of the telescopic boom 4. It is also possible to employ a multistage cylinder device 10 having a number of stages different from the number of stages of the boom 4. For example, in the first embodiment, the multi-stage cylinder device 10 is configured in four stages, but the telescopic boom 4 to which the multi-stage cylinder apparatus 10 can be applied does not have to be configured in four stages. Also good. Therefore, the versatility of the boom telescopic device can be improved while suppressing an increase in the diameter of the cylinder.

  In the first embodiment, the extension pressure chambers 16 and 56 of the first stage cylinder tubes 12 and 52 and the extension pressure chambers 26 and 66 of the second stage cylinder tubes 22 and 62 are connected to the second stage cylinder tube 22, Since the communication holes 24 and 64 provided in the bottom portions 22a and 62a of the 62 communicate with each other, it is not necessary to provide a pipe for introducing pressure oil, and the telescopic boom 4 can be configured even in the case of a plurality of stages. It is possible to prevent the internal configuration from becoming complicated.

  Further, in the first embodiment, both the first-stage cylinder tubes 12 and 52 are arranged side by side in a direction orthogonal to the extending direction, so that they are arranged in the telescopic boom 4 having a vertically long cross section. Especially effective. That is, if the boom telescopic device is arranged so that the first stage cylinder tubes 12 and 52 are aligned in the longitudinal direction of the cross section of the telescopic boom 4, the space in the telescopic boom 4 can be used effectively and the cylinder outer diameter can be reduced. It is possible to suppress the restriction. Moreover, since the length of the multistage cylinder device 10 in the contracted state can be shortened, it can be effective when applied to the telescopic boom 4 that is desired to be short in the contracted state.

  In the first embodiment, as shown in FIG. 3, the external communication pipe 42 is constituted by pipes connected on the surfaces on the separated sides of the first-stage cylinder tubes 12 and 52, but is not limited thereto. It is not a thing. In other words, the external communication pipe 42 is configured as described above for easy understanding, but instead, the two adjacent first-stage cylinder tubes 12 and 52 are connected to each other on the adjacent side surfaces by the external communication pipe 42. You may make it the structure to make.

  In the first embodiment, each of the cylinder units 11 and 51 has a multi-stage structure. However, the present invention is not limited to this, and one may have a multi-stage structure and the other may have a single-stage structure. In the case of a multi-stage structure, it may be three or more stages. Moreover, it is not restricted to the structure divided | segmented into two cylinder units, It is good also as a structure divided | segmented into three or more cylinder units. In this case, the cylinder units adjacent to each other are arranged in opposite directions. In this case, only the cylinder units located at both ends are coupled to the telescopic boom 4.

<< Embodiment 2 >>
In the first embodiment, each cylinder unit 11, 51 of the multistage cylinder device 10 is constituted by a single-acting hydraulic cylinder, but as shown in FIG. 5, the multistage cylinder device of the boom telescopic device according to the second embodiment. In FIG. 10, each cylinder unit 11, 51 is constituted by a double-acting hydraulic cylinder. That is, the multistage cylinder device 10 is configured as an expansion / contraction drive source for the telescopic boom 4. Therefore, in the second embodiment, pressure oil is introduced from the hydraulic pump both when the telescopic boom 4 is extended and contracted. In FIG. 5, for the sake of convenience, the thickness of the first stage cylinder tubes 12 and 52 is omitted. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A first oil supply / discharge pipe 5 and a second oil supply / discharge pipe 7 are provided at the base end 1 of the telescopic boom 4. The first oil supply / discharge pipe 5 is connected to an oil passage 38 in the third-stage cylinder 32 in the base end side cylinder unit 11. The first oil supply / discharge pipe 5 introduces the pressure oil into the apparatus when the boom expansion / contraction apparatus 80 is extended, and discharges the pressure oil outside the apparatus when the expansion / contraction apparatus 2 is contracted.

  Unlike the first embodiment, the third-stage cylinder 32 is a hollow cylinder tube. The third-stage cylinder tube 32 is provided with an oil passage 38 made of a pipe. In the third-stage cylinder tube 32, a space around the oil passage 38 is an oil chamber 39, and the second oil supply / discharge pipe 7 is communicated with the oil chamber 39. The second oil supply / discharge pipe 7 discharges the pressure oil outside the apparatus when the multistage cylinder device 10 is extended, and introduces the pressure oil into the apparatus when the multistage cylinder device 10 is contracted.

  In each cylinder unit 11, 51, the bottom portions 22 a, 62 a of the second stage cylinder tubes 22, 62 are configured in a thick plate shape having a larger diameter than the body portions 22 b, 62 b, respectively. The bottom portions 22a and 62a of the second-stage cylinder tubes 22 and 62 are slidable while maintaining a liquid-tight state with respect to the inner peripheral surfaces of the body portions 12b and 52b of the first-stage cylinder tubes 12 and 52. . Similarly, the bottom portions 32a and 72a of the third-stage cylinder tubes 32 and 72 are formed in a thick flat plate shape having a larger diameter than the body portions 32b and 72b. The bottom portions 32a and 72a of the third-stage cylinder tubes 32 and 72 are slidable while maintaining a liquid-tight state with respect to the inner peripheral surfaces of the body portions 22b and 62b of the second-stage cylinder tubes 22 and 62. .

  In the first stage cylinder tubes 12 and 52, the expansion pressure chambers 16 and 56 and the contraction pressure chambers 18 and 58 are partitioned by the second stage cylinder tubes 22 and 62. The interior of the chamber 62 is divided into the expansion pressure chambers 26 and 66 and the contraction pressure chambers 28 and 68 by the third-stage cylinder tubes 32 and 72. The pressure chambers 18 and 58 for contraction of the first stage cylinder tubes 12 and 52 are between the top portions 12c and 52c of the first stage cylinder tubes 12 and 52 and the bottom portions 22a and 62a of the second stage cylinder tubes 22 and 62, respectively. It is formed around the second stage cylinder tubes 22 and 62. The pressure chambers 28 and 68 for contraction of the second-stage cylinder tubes 22 and 62 are provided between the top portions 22c and 62c of the second-stage cylinder tubes 22 and 62 and the bottom portions 32a and 72a of the third-stage cylinders 32 and 72, respectively. It is formed around the three-stage cylinders 32 and 72.

  In the base end side cylinder unit 11, a contraction pressure chamber 28 in the second stage cylinder tube 22 and an oil chamber 39 in the third stage cylinder 32 are located in the vicinity of the bottom 32 a of the body portion 32 b of the third stage cylinder 32. A communication hole 35 is formed.

  The contraction pressure chamber 18 of the first stage cylinder tube 12 of the base end side cylinder unit 11 and the contraction pressure chamber 58 of the first stage cylinder tube 52 of the distal end side cylinder unit 51 are provided with expansion pipes 81 and 91 described later. Through the contraction external communication pipe 44.

  In each cylinder unit 11, 51, the contraction pressure chambers 18, 58 of the first-stage cylinder tubes 12, 52 and the contraction pressure chambers 18, 68 of the second-stage cylinder tubes 22, 62 are adjustable in length. The pipes 81 and 91 communicate with each other. The telescopic pipes 81 and 91 are fixed to the outer cylinders 82 and 92 fixed to the body portions 12b and 52b of the first stage cylinder tubes 12 and 52 by brackets 45 and 46, and the second stage cylinder tubes 22 and 62, respectively. In addition, there are provided inner cylinders 83 and 93 which are inserted into the outer cylinders 82 and 92 so as to be movable forward and backward. The outer cylindrical bodies 82 and 92 are formed of a bottomed cylindrical body that is formed in a length substantially the same as the length of the first-stage cylinder tubes 12 and 52 and extends straight. The outer cylinders 82 and 92 are arranged in a posture extending in the axial direction of the multistage cylinder device 10. Both the outer cylindrical bodies 82 and 92 are communicated with each other by the contracting external communication pipe 44. That is, in the second embodiment, the contraction external communication pipe 44 is communicated with the contraction pressure chambers 18 and 58 of the first-stage cylinder tubes 12 and 52 via the outer cylindrical bodies 82 and 92.

  The inner cylinders 83 and 93 are connected at one end to the top portions 22c and 62c of the second-stage cylinder tubes 22 and 62 or the trunk portions 22b and 62b in the vicinity thereof, and the pressure chambers for contraction of the second-stage cylinder tubes 22 and 62 are connected. 28 and 68. The other ends of the inner cylinders 83 and 93 are inserted into the outer cylinders 82 and 92 in a liquid-tight manner. The insertion depth of the inner cylinders 83 and 93 is the second-stage cylinder tube 22 and the second-stage cylinder tubes 12 and 52. It is longer than 62 strokes. Seal members 85 and 95 are fitted into the end portions of the outer cylindrical bodies 82 and 92 to ensure the sealing performance at those portions.

  Next, operation | movement of the boom expansion-contraction apparatus of this Embodiment 2 is demonstrated. When the telescopic boom 4 is extended, as shown by an arrow in FIG. 5, pressure oil is supplied into the apparatus through the first oil supply / discharge pipe 5, while the oil chamber 39 and the contracting pressure oil chambers 18, 28, 58 are supplied. , 68 is discharged out of the apparatus through the second oil supply / discharge pipe 7.

  Thereby, in the base end side cylinder unit 11, the pressure oil supplied from the first oil supply / discharge pipe 5 is introduced into the extension pressure chambers 26, 16 of the second stage cylinder tube 22 and the first stage cylinder tube 12. . At the same time, the pressure oil in the contraction pressure chamber 18 of the first stage cylinder tube 12 is led out to the contraction external communication pipe 44, and this pressure oil passes through the outer cylinder body 82 and the inner cylinder body 83, and the second stage cylinder tube 22. Into the pressure chamber 28 for contraction. The pressure oil is guided to the oil chamber 39 of the third-stage cylinder tube 32 through the communication hole 35 of the third-stage cylinder tube 32 and is discharged out of the apparatus through the second oil supply / discharge pipe 7. As a result, the second-stage cylinder tube 22 moves relative to the third-stage cylinder tube 32 in the left direction in the figure, and the first-stage cylinder tube 12 moves in the same direction with respect to the second-stage cylinder tube 22. Move relative to.

  On the other hand, in the front end side cylinder unit 51, the pressure oil supplied through the external communication pipe 42 is introduced into the extension pressure chambers 56 and 66 of the first stage cylinder tube 52 and the second stage cylinder tube 62. At this time, the pressure oil in the contraction pressure chamber 58 of the first stage cylinder tube 52 goes to the contraction external communication pipe 44, and the pressure oil in the contraction pressure chamber 68 of the second stage cylinder tube 62 goes to the inner cylinder 93. Each is derived. These pressure oils are guided to the contraction pressure chamber 28 in the second stage cylinder tube 22 of the base end side cylinder unit 11 through the outer cylinders 92 and 82 and the inner cylinder 83 and then discharged through the second oil supply / discharge pipe 7. Is done. As a result, the second stage cylinder tube 62 moves relative to the first stage cylinder tube 52 in the left direction in the figure, and the third stage cylinder tube 72 moves in the same direction with respect to the second stage cylinder tube 62. Move relative to.

  Thereby, both the base end side cylinder unit 11 and the front end side cylinder unit 51 are extended, and the telescopic boom 4 is extended.

  On the other hand, when the telescopic boom 4 is contracted, the pressure oil flows in the direction opposite to the arrow shown in FIG. That is, while supplying the pressure oil into the apparatus through the second oil supply / discharge pipe 7, the pressure oil in the extension pressure oil chambers 16, 26, 56, 66 is discharged out of the apparatus through the first oil supply / discharge pipe 5. To do.

  In the base end side cylinder unit 11, the pressure oil introduced into the oil chamber 39 through the second oil supply / discharge pipe 7 is introduced into the pressure chamber 28 for contraction of the second-stage cylinder tube 22 through the communication hole 35. This pressure oil is further introduced into the contracting pressure chamber 18 of the first stage cylinder tube 12 through the inner cylinder 83 and the outer cylinder 82. At the same time, the pressure oil in the extension pressure chambers 16 and 26 of the first stage cylinder tube 12 and the second stage cylinder tube 22 is discharged from the first oil supply / discharge pipe 5 via the oil passage 38. As a result, the first stage cylinder tube 12 and the second stage cylinder tube 22 move to the right in FIG.

  On the other hand, in the front end side cylinder unit 51, the pressure oil flowing into the inner cylinder 83 is introduced into the contracting pressure chamber 68 of the second-stage cylinder tube 62 through the outer cylinders 82 and 92 and the inner cylinder 93. These are introduced into the contracting pressure chamber 58 of the first-stage cylinder tube 52 through both the outer cylinders 82 and 92 and the contracting external communication pipe 44. At this time, the pressure oil in the expansion pressure chambers 66 and 56 of the second-stage cylinder tube 62 and the first-stage cylinder tube 52 is guided to the proximal cylinder unit 51 through the external communication pipe 42, and then the first oil supply / discharge It is discharged from the tube 5. As a result, the second stage cylinder tube 62 moves relative to the first stage cylinder tube 52 in the right direction in the figure, and the third stage cylinder tube 72 moves in the same direction with respect to the second stage cylinder tube 62. Move relative to.

  Thereby, both the base end side cylinder unit 11 and the front end side cylinder unit 51 contract, and the telescopic boom 4 contracts.

  In the second embodiment, an external communication pipe 42 that communicates the expansion pressure chambers 16 and 56 of both cylinder units 11 and 51 and a contraction external communication pipe 44 that communicates the contraction pressure chambers 18 and 58 are provided. Thus, even when the multistage cylinder device 10 is configured as a telescopic drive source, it is possible to prevent the piping structure for communicating the pressure chambers 16, 56, 18, 58 from becoming complicated. Moreover, both cylinder units 11 and 51 can be expanded-contracted only by supplying pressure oil to one cylinder unit 11 and 51. FIG.

  Further, in the second embodiment, the contraction pressure chambers 18 and 58 of the first stage cylinder tubes 12 and 52 and the contraction pressure chambers of the second stage cylinder tubes 22 and 62 in the two-stage cylinder units 11 and 51, respectively. 28 and 68 are communicated with each other by telescopic pipes 81 and 91 whose lengths are adjustable, so that the second-stage cylinder tubes 22 and 62 are displaced relative to the first-stage cylinder tubes 12 and 52. Also, the expansion pipes 81 and 91 can absorb the relative displacement of the pressure chambers 18, 58, 28 and 68 for contraction, and the communication state of the pressure chambers 18, 58, 28 and 68 can be ensured. .

  Further, since the telescopic pipes 81 and 91 are constituted by the outer cylindrical bodies 82 and 92 and the inner cylindrical bodies 83 and 93 that are inserted into the outer cylindrical bodies 82 and 92 so as to be movable forward and backward, a high pressure acts. Thus, the length of the expansion and contraction pipes 81 and 91 can be adjusted while ensuring the sealing performance.

  The contracting external communication pipe 44 is not limited to the above configuration, and may be configured in a hose reel type, for example.

  In the second embodiment, the contraction external communication tube 44 is communicated with the contraction pressure chambers 18 and 58 of both the first-stage cylinder tubes 12 and 52 via both outer cylindrical bodies 82 and 92. Instead of this, as shown in FIG. 6, a configuration may be adopted in which the contracting external communication pipe 44 and the outer cylindrical bodies 82 and 92 are not communicated with each other.

  Other configurations, operations, and effects are the same as those of the first embodiment, although explanations thereof are omitted.

<< Embodiment 3 >>
In the second embodiment, the expansion pipes 81 and 91 of the cylinder units 11 and 51 are separately configured. However, in the third embodiment, the expansion pipes 100 of both the cylinder units 11 and 51 are integrated as shown in FIG. It is configured. That is, the third embodiment shares the outer cylinders 82 and 92 in the second embodiment. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The expansion pipe 100 is connected to the outer cylinder 101 fixed to the first stage cylinder tube 12 of the base end side cylinder unit 11 by the bracket 45 and the second stage cylinder tube 22 of the base end side cylinder unit 11. A proximal inner cylinder 102 as one inner cylinder and a distal inner cylinder 103 as a second inner cylinder connected to the second-stage cylinder tube 62 of the distal cylinder unit 11 are provided. The outer cylinder 101 is disposed so as to extend straight along the axial direction of the first stage cylinder tube 12, and the length thereof is substantially equal to the length of the first stage cylinder tube 12. The outer cylinder 101 is communicated with the pressure chamber 58 for contraction of the first-stage cylinder tube 52 in the distal end side cylinder unit 51 through the contraction external communication pipe 44.

  One end of the proximal-side inner cylinder 102 opens into the contracting pressure chamber 28 of the second-stage cylinder tube 22, and the other end enters one end of the outer cylinder 101, that is, the proximal end of the telescopic boom 4. It is inserted from the end on the part 1 side. A sealing member 106 is fitted into the end of the outer cylinder 101, and the sealing performance at this portion is ensured. The insertion depth of the base end side inner cylinder 102 is set to a length equal to or longer than the stroke of the second-stage cylinder tube 22.

  The distal end side inner cylinder 103 has one end that opens into the pressure chamber 68 for contraction of the second stage cylinder tube 62, and the other end that extends into the outer cylinder 101, that is, the distal end side of the telescopic boom 4. It is inserted from the end. A sealing member 107 is fitted into the end of the outer cylinder 101, and the sealing performance at this portion is ensured. The insertion depth of the base end side inner cylinder 102 is set to a length equal to or longer than the stroke of the second-stage cylinder tube 62. The other end of the distal end side inner cylinder 103 is configured to have a smaller diameter than the proximal end side inner cylinder 102 and is inserted inside the proximal end side inner cylinder 102. That is, the telescopic pipe 100 has a triple structure at this portion. The proximal end inner cylinder 102 may be configured to have a smaller diameter than the distal end inner cylinder 103 and the proximal end inner cylinder 102 may be inserted inside the distal end inner cylinder 103.

  According to the third embodiment, since both the proximal-side inner cylindrical body 102 and the distal-end-side inner cylindrical body 103 are fitted into one outer cylindrical body 101, the configuration is more compact than that of the second embodiment. And the number of parts can be reduced.

  Other configurations, operations, and effects are the same as those of the second embodiment although the description thereof is omitted.

  As described above, in the first to third embodiments, the cylinder units 11 and 51 are preferably pivotally supported in the undulating direction of the telescopic boom 4. This makes it difficult for a bending load to be applied to the multistage cylinder device 10 during crane operations, etc. Therefore, the multistage cylinder device 10 mainly plays a role of an extension operation (or extension operation). On the other hand, since the telescopic boom 4 plays a role of supporting the bending load applied to the boom during crane operation or the like, the number of stages of the telescopic boom 4, the length of each boom body, It will be possible to freely adjust the overlap margin. Therefore, the cross-sectional dimension of the telescopic boom 4 can be reduced and the weight can be reduced while taking advantage of the advantage that the strength of the telescopic boom 4 can be improved. Therefore, it can be suitable for a self-propelled crane vehicle equipped with the telescopic boom 4.

It is a side view which shows roughly the whole structure of the crane vehicle with which the boom expansion-contraction apparatus which concerns on Embodiment 1 of this invention was applied. It is a conceptual diagram which shows schematically the telescopic boom of the said crane vehicle in the expansion | extension state. It is sectional drawing which shows the whole structure of the said boom expansion-contraction apparatus. FIG. 3 is a view corresponding to FIG. 2 showing a contracted state of the telescopic boom. It is sectional drawing which shows roughly the whole structure of the boom expansion-contraction apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the other structure of Embodiment 2 roughly. It is sectional drawing which shows roughly the whole structure of the boom expansion-contraction apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

11 Base end side cylinder unit (cylinder unit)
12,52 First stage cylinder tube (cylinder tube)
16, 56 Extension pressure chamber 18, 58 Contraction pressure chamber 22, 62 Second stage cylinder tube (cylinder tube)
22a, 62a Bottom portion 26, 66 Extension pressure chamber 28, 68 Contraction pressure chamber 32, 72 Third stage cylinder 42 External communication pipe 44 Contraction external communication pipe 51 Tip side cylinder unit (cylinder unit)
81, 91 Expandable pipe 82, 92 Outer cylinder 83, 93 Inner cylinder 100 Extendable pipe 101 Outer cylinder 102 Base end side inner cylinder (first inner cylinder)
103 distal end side inner cylinder (second inner cylinder)

Claims (6)

As a drive source for at least extension of the telescopic boom, a multi-stage cylinder device in which a plurality of boom length-direction cylinders are coupled is provided, and the base end side of the multi-stage cylinder device in the telescopic boom is the boom base end, Are connected to the boom tip,
The multistage cylinder device is divided into a plurality of cylinder units,
At least one cylinder unit in the cylinder units adjacent to each other has a multi-stage structure including a plurality of cylinder tubes,
Adjacent cylinder units are coupled with their directions reversed, and these cylinder tubes are arranged side by side in the cylinder radial direction at the coupling part of both cylinder units where the outermost cylinder tubes are coupled together. And
A boom telescopic device, characterized in that an external communication pipe is provided for communicating the extension pressure chambers in the outermost cylinder tubes coupled to each other. Each cylinder tube in the multistage cylinder device configured as an expansion / contraction drive source for the telescopic boom is partitioned into the expansion pressure chamber for expanding the cylinder unit and the contraction pressure chamber for contracting the cylinder unit. And
The boom telescopic device according to claim 1, further comprising a contracting external communication pipe that communicates the contracting pressure chambers in the outermost cylinder tubes coupled to each other.   The cylinder unit having the multi-stage structure is provided with a length-adjustable expansion / contraction pipe that communicates the contraction pressure chamber in the outermost cylinder tube and the contraction pressure chamber in the inner cylinder tube. The boom telescopic device according to claim 2, wherein   The expansion pipe is arranged in a posture extending in the expansion / contraction direction of the multistage cylinder device, is fixed to the outermost cylinder tube and is connected to the pressure chamber for contraction, and is fixed to the inner cylinder tube. 4. The boom telescopic device according to claim 3, further comprising: an inner cylinder that is communicated with a contracting pressure chamber and is fitted and inserted into the outer cylinder so as to be movable forward and backward. The expansion pipes are respectively provided in cylinder units coupled to each other,
The boom telescopic device according to claim 4, wherein the contracting external communication pipes are respectively connected to outer cylinders of both cylinder units. The telescopic pipe is shared by two adjacent cylinder units having an outer cylinder, a first inner cylinder, and a second inner cylinder,
The outer cylinder is fixed to the outermost cylinder tube and communicated with a pressure chamber for contraction in the outermost cylinder tube;
One end of the first inner cylinder is fixed to the inner cylinder tube of one cylinder unit and communicated with the pressure chamber for contraction, and the other end is inserted into the outer cylinder so as to be movable forward and backward.
The second inner cylinder has a diameter different from that of the first inner cylinder, one end is fixed to the inner cylinder tube of the other cylinder unit and communicated with the contraction pressure chamber, and the other end is the outer cylinder. The boom telescopic device according to claim 3, wherein the boom telescopic device is fitted into the cylinder so as to be movable forward and backward.

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