JP5570206B2 - boom - Google Patents

Description

  The present invention relates to a boom of a work vehicle such as an aerial work vehicle or a mobile crane.

  Conventionally, as a boom of a work vehicle such as an aerial work vehicle or a mobile crane, those having various cross-sectional shapes are known, and a slide member is disposed between the outer box member and the inner box member. Are known.

  For example, Patent Document 1 includes an upper surface slider and a side surface slider as slide members installed between an outer box member and an inner box member, and these are mounted apart in the boom longitudinal direction (axial direction). A configuration is disclosed. According to this configuration, since the outer box member is elastically deformed freely, internal stress can be suppressed.

  In Patent Document 2, the upper section and the lower section are welded to form a hollow boom, and a rectangular or oval reinforcing recess is press-formed at a distance along the longitudinal direction in the vertical section of the upper section. The configuration is disclosed. According to this configuration, it is possible to increase the buckling strength while reducing the welding amount, and to increase the size of the boom section and the weight of the boom.

Japanese Patent No. 2801573 JP 2000-16663 A

  However, in the configuration of Patent Document 1, since the slide plate reaction force of the upper plate portion becomes large and fatigue strength becomes a problem, it is necessary to increase the plate thickness or attach a reinforcing plate.

  In addition, although the strength of the configuration of Patent Document 2 is high, there is a problem in that processing takes time and costs increase because of the double plate structure of the upper half and the lower half.

  Accordingly, an object of the present invention is to provide a boom that can disperse the stress of the outer box member and is easy to process.

In order to achieve the above object, the boom of the present invention is attached to an outer box member having a columnar space, an inner box member that is nested in the columnar space, and a rear end portion of the inner box member. A slide member that is in sliding contact with the inner surface of the outer box member, wherein both ends of the upper plate portion of the cross section of the outer box member are bent downward to form a swash plate portion, and the slide member The outer box member is formed of a single member so as to be in sliding contact with only the vicinity of the upper and lower bent portions of the swash plate portion of the cross section of the outer box member .

  Moreover, the said slide member can be set as the structure which slidably contacts to the upper-plate part of the cross section of the said outer box member.

  Furthermore, the said slide member can be set as the structure which slidably contacts to the side-plate part of the cross section of the said outer box member.

The slide member may be formed such that a cross section in a direction orthogonal to the axial direction of the boom has a concave surface facing the swash plate portion .

Thus, the boom of the present invention is a boom including an outer box member, an inner box member, and a slide member, and both ends of the upper plate portion of the cross section of the outer box member are bent downward to form a swash plate portion. In addition, the sliding member can be slidably contacted only in the vicinity of both the upper and lower bent portions of the swash plate portion, so that the stress generated in the outer box member can be dispersed and tensile stress is generated on the outer surface of the outer box member. It becomes easy to confirm visually.

  Moreover, the slide member is configured to be in sliding contact with the upper plate portion of the cross section of the outer box member, so that the movement and deformation of the upper plate portion can be suppressed, and the strength against bending in the vertical direction of the boom can be increased.

  Furthermore, the slide member is configured to be in sliding contact with the side plate portion of the cross section of the outer box member, thereby suppressing the movement and deformation of the side plate portion and increasing the strength against the lateral buckling of the boom.

  Since the slide member is configured to be in sliding contact with only the vicinity of both the upper and lower bent portions of the swash plate portion of the cross section of the outer box member, the center portion of the swash plate portion is not pressed, so the slide member is pulled on the inner surface of the outer box member. Stress is less likely to occur.

It is sectional drawing explaining the structure of the boom of Example 1. FIG. (A) is sectional drawing, (b) is an expanded sectional view which expands and demonstrates the A section of (a). It is a side view explaining the whole structure of an aerial work vehicle. It is a perspective view explaining the structure of a boom. (A) is a perspective view, (b) is an action figure of force. It is explanatory drawing explaining the stress state which generate | occur | produces in an outer box member. It is sectional drawing explaining the structure of the boom of Example 2. FIG. (A) is sectional drawing, (b) is an expanded sectional view which expands and demonstrates the A section of (a). It is sectional drawing explaining the structure of the boom of Example 3. FIG. (A) is sectional drawing, (b) is an expanded sectional view which expands and demonstrates the A section of (a). It is sectional drawing explaining the structure of the boom of Example 4. FIG. (A) is sectional drawing, (b) is an expanded sectional view which expands and demonstrates the A section of (a). It is a side view explaining the structure of the boom of Example 5. FIG. (A) is sectional drawing, (b) is an expanded sectional view which expands and demonstrates the A section of (a). It is a disassembled perspective view which decomposes | disassembles and demonstrates the structure of the boom of Example 5. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the whole structure of the aerial work vehicle 1 provided with the boom 14 of the present invention will be described with reference to FIG. In this embodiment, the aerial work vehicle 1 will be described as a work vehicle including the boom 14 of the present invention. However, the present invention is not limited to this, and the boom of the present invention is also applied to a mobile crane such as a rough terrain crane. 14 can be applied.

  As shown in FIG. 2, the aerial work vehicle 1 of the present embodiment is turned to a vehicle body 10 that is a main body portion of a vehicle having a traveling function, a traveling cabin 11 attached to the front of the vehicle body 10, and the vehicle body 10. A turntable 12 that can be attached, a bracket 13 erected on the turntable 12, a boom 14 attached to the bracket 13, and an outrigger 9 for preventing overturning provided at the four corners of the vehicle body 10. And.

  Further, the boom 14 is configured in a three-stage telescoping manner by a base end boom 17, an intermediate boom 18, and a front end boom 19, and can be expanded and contracted by expanding and contracting an internal expansion / contraction cylinder (not shown). .

  As shown in FIG. 1, the base end boom 17 and the intermediate boom 18 (the same as the front end boom 19) are formed by bending a single high-tensile steel plate into an octagonal cylinder by press working. The joint is formed by welding in the vicinity of the center.

  That is, the base boom 17 and the intermediate boom 18 (the same applies to the tip boom 19) are formed in an octagonal cross section as a whole by bending the upper half part four times and bending the lower half part four times.

  Further, the base end side of the base end boom 17 is slidably attached to a shaft installed horizontally on the bracket 13, and the hoisting cylinder 16 stretched between the bracket 13 and the base end boom 17 is expanded and contracted. By doing so, the entire boom 14 can be raised and lowered.

  Further, a bucket 15 as a work table on which a worker rides to perform work at a high place is attached to the front end side of the front end boom 19 so as to be freely slidable from side to side.

  In addition, the boom 14 includes a rear end portion of the intermediate boom 18 in addition to a base end boom 17 as an outer box member and an intermediate boom 18 as an inner case member nested in the base end boom 17. And slide members 2, 3, and 4 that are in sliding contact with the inner surface of the outer proximal boom 17. A substantially similar slide member is also arranged between the intermediate boom 18 as the outer box member and the tip boom 19 as the inner box member, but the description thereof is omitted here.

  And in the boom 14 of this invention, as shown to Fig.1 (a), both ends of the upper-plate part 171 of the cross section of the base end boom 17 are bend | folded below, and a pair of swash plate part 174,174 is left-right symmetric. At the same time, the slide member 2 is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174.

  As shown in FIG. 1A, the swash plate portion 174 is formed by bending both ends of the upper plate portion 171 downward by 45 ° that is a predetermined bending angle with respect to the vicinity of the center. Note that a certain degree of stress dispersion effect can be obtained if the bending angle is 30 ° to 60 °, but it is preferably about 45 °.

  In addition, as shown in FIG. 1 (b), the slide member 2 disposed at the upper part of the cross section is formed in a plate shape having a predetermined length and thickness by a synthetic resin such as nylon or metal. (Not shown) or the like is fixed to the swash plate portion 184 of the intermediate boom 18.

  That is, the slide member 2 corresponds to the width of a gap formed between the proximal boom 17 and the intermediate boom 18 so that the sliding of the intermediate boom 18 with respect to the proximal boom 17 can be reduced and smoothly slid. It is formed with only a thickness.

  As shown in FIG. 1B, the slide member 2 of this embodiment is slidably in contact with both the bent portion vicinity 174a and 174a and the center vicinity 174b in the swash plate portion 174. Yes.

  More specifically, the slide member 2 is in sliding contact with the bent portions 174a and 174a on the inner side slightly from the bent portions 176 and 177 of the swash plate portion 174, but the bent portions 176 and 177, which are the bending positions, are in contact with each other. There is no contact.

  Further, as shown in FIG. 3A, the slide member 2 is attached in the vicinity of the rear end portion of the intermediate boom 18 so that the moment load from the bucket 15 can be transmitted to the base end boom 17 in the boom axis direction. ing.

  Therefore, in addition to the weight of the boom 14, as shown in FIG. 3B, W × a = R2 × b is established with the lower slide member 5 in the vicinity of the distal end of the proximal boom 17 as a fulcrum. The reaction force of a / b × W acts on the upper portion of the proximal boom 17 in a concentrated manner.

  The relationship between the bending width B obtained by projecting the swash plate portion 174 in the surface direction of the upper plate portion 171 and the plate thickness t is B / t = 5 from the bending portion workability, the sliding contact surface pressure, and the sliding contact operability. It is preferable that the configuration is as described above.

  Further, the slide member 3 arranged at the side and the slide member 4 arranged at the lower part are respectively attached to the side plate part 183 and the lower swash plate part 185 of the intermediate boom 18 by screws (not shown).

  Next, the operation of the boom 14 of this embodiment will be described.

  Thus, the boom 14 of the present invention is a boom 14 including the base end boom 17 as the outer box member, the intermediate boom 18 as the inner box member, and the slide members 2, 3, and 4.

  For this reason, the friction between the base end boom 17 as the outer box member and the intermediate boom 18 as the inner box member can be reduced, and the intermediate boom 18 can be moved smoothly.

  Then, both ends of the upper plate portion 171 of the cross section of the base end boom 17 are bent downward to form a swash plate portion 174, and the slide member 2 is at least bent portion 174a, 174a on both the upper and lower sides of the swash plate portion 174. By sliding contact, the stress generated in the proximal boom 17 can be dispersed, and since tensile stress is generated on the outer surface of the proximal boom 17, it is easy to visually confirm even if a crack occurs.

  That is, as shown in FIG. 3B, a force upward from the proximal end portion of the intermediate boom 18 (from the inner surface to the outer surface) acts on the proximal boom 17 through the slide member 2.

  Then, in order to exert a reaction force on this force, an internal stress as shown in FIG. In FIG. 4, the curve drawn on the swash plate portion 174 is an equal tensile stress line connecting points having the same tensile stress, and the tensile stress is gradually increased from the outer surface toward the inner surface. It shows how it decreases.

  As shown in FIG. 4, according to the configuration including the swash plate portion 174 and the slide member 2 of the present embodiment, the tensile stress on the inner surface side of the bent portions 176 and 177 as in the prior art is suppressed, and the swash plate portion 174. Tensile stress is generated on the outer surface side of the center vicinity 174b and the outer surface side of the bent portion vicinity 174a, 174a. Moreover, the absolute value of the generated tensile stress is smaller than that in the prior art.

  This is because the slide member 2 pushes up the swash plate portion 174 obliquely, so that both the upper plate portion 171 and the side plate portion 173 are expanded. This is because the inside is not pulled.

  From such an action, it is not necessary to employ a method of thickening the entire plate thickness or partially attaching a reinforcing plate, which has been conventionally performed in order to ensure fatigue strength. The boom 17 and the intermediate boom 18 can be manufactured with a single plate.

  Moreover, in this invention, since it manufactures with one board, it can reduce a press work cost, distortion removal, and welding (one place) of joining, and also does not need to thicken board thickness or to attach a reinforcement board. Therefore, the cost required for press working, strain relief, and welding can be suppressed as compared with the case of manufacturing with two plates while reducing the weight.

  Hereinafter, the boom 14 provided with the slide member 2A different from the said Example is demonstrated using FIG. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  First, the configuration will be described. In the boom 14 of this embodiment, as shown in FIG. 5A, both ends of the upper plate portion 171 of the base end boom 17 are bent downward to form swash plate portions 174 and 174. At the same time, the slide member 2A is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174.

  As shown in FIG. 5B, the slide member 2A is formed in a plate shape bent by a synthetic resin or metal, and includes a swash plate sliding contact portion 21 that is in sliding contact with the swash plate portion 174, and a slanting member. An upper plate sliding contact portion 22 that is bent at an angle of 45 ° with respect to the plate sliding contact portion 21 and is in sliding contact with the upper plate portion 171 is integrally formed.

  Therefore, the swash plate sliding contact portion 21 of the slide member 2A is slidably in contact with both the bent portion vicinity 174a and 174a and the center vicinity 174b in the swash plate portion 174.

  Furthermore, the upper plate sliding contact portion 22 of the slide member 2A is slidably in contact with the upper plate portion 171 of the cross section of the base end boom 17 as the outer box member.

  Next, the operation will be described. In the boom 14 of the present embodiment, the swash plate portion 174 is formed, and the slide member 2A is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174, so that the base end boom. In addition to being able to disperse the stress generated at 17, a tensile stress is generated on the outer surface of the proximal boom 17, so that even if a crack occurs, it can be easily confirmed visually.

  In addition, since the slide member 2A has the upper plate sliding contact portion 22 that is in sliding contact with the upper plate portion 171 of the cross section of the base end boom 17 as the outer box member, the movement and deformation of the upper plate portion 171 are suppressed, The strength against bending of the boom 14 in the vertical direction can be increased.

  Other configurations and operational effects are substantially the same as those in the above-described embodiment, and thus the description thereof is omitted.

  Hereinafter, the boom 14 provided with the slide member 2B different from the said Example is demonstrated using FIG. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  First, the configuration will be described. In the boom 14 of the present embodiment, as shown in FIG. 6A, both ends of the upper plate portion 171 of the base end boom 17 are bent downward to form swash plate portions 174 and 174. At the same time, the slide member 2B is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174.

  As shown in FIG. 6B, the slide member 2B is formed in a plate shape bent by a synthetic resin or metal, and includes a swash plate sliding contact portion 21 that is in sliding contact with the swash plate portion 174, and a slanting member. A side plate sliding contact portion 23 that is bent at an angle of 45 ° with respect to the plate sliding contact portion 21 and is in sliding contact with the side plate portion 173 is integrally provided.

  Therefore, the swash plate sliding contact portion 21 of the slide member 2B is slidably in contact with both the bent portion vicinity 174a and 174a and the center vicinity 174b in the swash plate portion 174.

  Further, the side plate sliding contact portion 23 of the slide member 2B is slidably in contact with the side plate portion 173 of the cross section of the base end boom 17 as the outer box member.

  Next, the operation will be described. In the boom 14 of this embodiment, the swash plate portion 174 is formed, and the slide member 2B is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174, so that the proximal end boom. In addition to being able to disperse the stress generated at 17, a tensile stress is generated on the outer surface of the proximal boom 17, so that even if a crack occurs, it can be easily confirmed visually.

  In addition, since the slide member 2B has the side plate sliding contact portion 23 that comes into sliding contact with the side plate portion 173 of the cross section of the base end boom 17 as the outer box member, the movement and deformation of the side plate portion 173 are suppressed, and the boom 14 Strength against lateral buckling can be increased.

  Other configurations and operational effects are substantially the same as those in the above-described embodiment, and thus the description thereof is omitted.

  Hereinafter, the boom 14 provided with the slide member 2C different from the said Example is demonstrated using FIG. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  First, the configuration will be described. In the boom 14 of this embodiment, as shown in FIG. 7A, both ends of the upper plate portion 171 of the base end boom 17 are bent downward to form swash plate portions 174 and 174. In addition, the slide member 2 </ b> C is in sliding contact with only the bent portion vicinity 174 a and 174 a of the swash plate portion 174.

  As shown in FIG. 7B, the slide member 2C is formed in a plate shape with synthetic resin or metal, and includes a swash plate sliding contact portion 21 slidably contacting the swash plate portion 174, and the swash plate. And a concave portion 21a provided in the vicinity of the center of the sliding contact portion 21 in the width direction.

  Accordingly, the swash plate sliding contact portion 21 of the slide member 2C is slidably in contact with only the bent portion vicinity 174a and 174a in the swash plate portion 174, and is in contact with the center vicinity 174b of the swash plate portion 174. Absent.

  Next, the operation will be described. In the boom 14 of the present embodiment, the swash plate portion 174 is formed, and the slide member 2C is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174, so that the base end boom. 17 can be applied only to the vicinity of the bent portions 174a and 174a, and since a tensile stress is generated on the outer surface of the proximal boom 17, it is easy to visually confirm even if a crack occurs.

  In addition, since the slide member 2C is in sliding contact with only the bent portion vicinity 174a and 174a of the swash plate portion 174 of the cross section of the base end boom 17 as the outer box member, a load is transmitted to the bent portion vicinity 174a and 174a to the outside. Since the center vicinity 174b is not expanded while being spread, the tensile stress is hardly generated inside the bent portions 176, 177 of the proximal boom 17.

  Other configurations and operational effects are substantially the same as those in the above-described embodiment, and thus the description thereof is omitted.

  In the fourth embodiment, the case where the slide member 2C is formed as a single member has been described. However, the present invention is not limited to this, and the slide member 2C may be divided into two pieces. .

  Hereinafter, the boom 14 provided with the slide member 2D different from the said Example is demonstrated using FIG. The description of the same or equivalent parts as those described in the above embodiment will be given the same reference numerals.

  First, the configuration will be described. In the boom 14 of this embodiment, as shown in FIG. 8A, both ends of the upper plate portion 171 of the base end boom 17 are bent downward to form swash plate portions 174 and 174. In addition, the slide member 2D is in sliding contact with the bent portion vicinity 174a, 174a of the swash plate portion 174.

  As shown in FIGS. 8B and 9, the slide member 2 </ b> D includes a swash plate sliding contact portion 21 that is formed in a plate shape with synthetic resin or metal and is in sliding contact with the swash plate portion 174, and an intermediate boom 18. And a retainer 24 as a base that supports the swash plate sliding contact portion 21 and thin plate-like shims 25 and 26 that adjust the distance between the swash plate sliding contact portion 21 and the swash plate portion 174. Yes.

  The retainer 24 has upright portions on both sides of the main body portion for transmitting the force. The upright portions are provided with bolt holes, and the bolts 27 are elongated holes provided on the end surface of the swash plate sliding contact portion 21. To be engaged.

  Further, one shim 26 is provided with an opening 26a in the vicinity of the center of the plate surface, so that the vicinity of the center of the swash plate sliding contact portion 21 that has received the reaction force can be deformed inward.

  Next, the operation will be described. In the boom 14 of this embodiment, the swash plate portion 174 is formed, and the slide member 2D is in sliding contact with only the bent portion vicinity 174a, 174a of the swash plate portion 174.

  Since the shim 26 has an opening 26a in the vicinity of the center, the slide member 2D is deformed so that the vicinity of the center is depressed when receiving a reaction force, and the swash plate portion 174 in the cross section of the base end boom 17 as an outer box member. The reaction force is received only in the vicinity of the bent portions 174a and 174a.

  Therefore, the stress generated in the proximal boom 17 can be applied only to the vicinity of the bent portions 174a and 174a, and since a tensile stress is generated on the outer surface of the proximal boom 17, it is easy to visually confirm even if a crack occurs.

  For this reason, by transmitting the load only to the bent portion vicinity 174a, 174a and pushing it outward, the center neighborhood 174b does not spread, so that tensile stress is hardly generated inside the bent portions 176, 177 of the proximal boom 17. .

  Other configurations and operational effects are substantially the same as those in the above-described embodiment, and thus the description thereof is omitted.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are not limited to the present invention. included.

  For example, in the second and third embodiments, the case where the swash plate sliding contact portion 21, the upper plate sliding contact portion 22 and the side plate sliding contact portion 23 are integrally formed has been described. However, the present invention is not limited to this. It can also be formed as a separate member and shifted in the direction of the axis of the boom 14.

  Moreover, although the said Example demonstrated the case where the boom 14 was comprised by 3 steps | paragraphs of the base end boom 17, the intermediate | middle boom 18, and the front end boom 19, it is not limited to this and is 2 steps | paragraphs. The present invention can be applied even if there are four or more stages.

  Furthermore, in the said Example, although the case where the lower half part of the boom 14 was bent 4 times and formed in an octagonal cross section as a whole was demonstrated, it is not limited to this, As a cross-sectional shape of a lower half part The present invention can be applied even to multi-point bending of 3 times bending, 4 times bending, 5 times bending or more.

1 High-altitude work vehicle 14 Boom 17 Base end boom (outer box member)
171 Upper plate portion 174 Swash plate portion 174a Near bent portion 174b Near center 18 Intermediate boom (inner box member)
181 Upper plate portion 184 Swash plate portion 2, 2A, 2B, 2C, 2D Slide member 21 Swash plate sliding contact portion 21a Recess 22 Upper plate sliding contact portion 23 Side plate sliding contact portion 24 Retainer 25 Shim 26 Shim 26a Opening portions 3 and 4 , 5 Slide member

Claims (2)

An outer box member having a columnar space, an inner box member that is nested in the columnar space, and a slide member that is attached to a rear end portion of the inner box member and is in sliding contact with the inner surface of the outer box member. A boom to provide,
Both ends of the upper plate portion of the cross section of the outer box member are bent downward to form a swash plate portion, and the slide member is only near the upper and lower bent portions of the swash plate portion of the cross section of the outer box member. A boom formed of a single member so as to be in sliding contact . 2. The boom according to claim 1, wherein the slide member is formed such that a cross section in a direction orthogonal to an axial direction of the boom is formed with a concave surface facing the swash plate portion .

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