JP2007077707A - Blade device for work machine, and construction/civil engineering vehicle having the blade device mounted thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blade device for a work machine, which exhibits drastic improvement in excavation efficiency compared with a conventional blade, and prevents earth from dropping at the time of rotation and push-turning during transportation of the earth, and to provide a work vehicle having the blade device mounted thereon. <P>SOLUTION: The blade device has a total blade width W, and is formed of a central front surface portion (12), linkage front surface portions (13), and end front surface portions (14). The central front surface portion (12) has a linear first cutting edge (15) attached to a lower edge thereof, and has a predetermined blade width W1. Each linkage front surface portion (13) has a second cutting edge (16) which is extended from the first cutting edge (15) and bent rearward from the same by a predetermined angle δ. Each end front surface portion (14) has a third cutting edge (17) which is extended from the second cutting edge (16) and bent with respect to an extension of the first cutting edge (15), by an angle θ. Further the cutting edges (15 to 17) extend from the lower edges of the front surface portions (12 to 14), respectively, in a tangent direction, and provided that a cutting edge angle α of the cutting edges (15 to 17) is in an excavation position ranging from 40 to 55°, and that a height from the tip of the first cutting edge (15) to an upper edge of an earth retaining plate is represented by H, a radius R2 satisfies the following equation (I): R2=(0.7 to 1.0)×H. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a blade equipped in various working vehicles such as a bulldozer and a wheel dozer, and is particularly suitable for work such as excavation, soil removal, and leveling, and has excellent work efficiency, fuel efficiency, economy, etc. The present invention relates to a blade device for a work machine that realizes an improvement in construction and a construction / civil engineering vehicle equipped with the blade device.

  In various work sites such as construction work and civil engineering work, for example, various work vehicles such as bulldozers and wheel dozers are frequently used. This type of work vehicle is equipped with a blade that is a work attachment. This blade is widely used for dozer work such as excavation, earthing, embankment, compaction and leveling.

  In order to maximize the work efficiency of this work vehicle, the amount of soil per blade (blade capacity) must be increased as much as possible, the resistance during excavation and soiling should be as small as possible, and various different soil properties. It is important to satisfy various conditions such as conforming to the above and not soiling on the blade during excavation. In addition, it is preferable to simultaneously perform embankment, compaction, and leveling because it leads to a significant improvement in work efficiency. Finding the optimum blade structure, shape, width, height, cutting edge position and excavation angle that satisfy these conditions will improve the work efficiency of work machines and reduce fuel consumption. Leading to advantages such as shortening the overall construction period. In order to maximize the bulldozer's work capacity, the balance of force in the bulldozer's earth work must have a traction force larger than the soil resistance and a vehicle drive force larger than the traction force.

  By the way, most of the engine output required for excavation / soil work in the bulldozer is consumed by the driving force of the vehicle and the traction force during excavation / soil. Therefore, it is important to reduce energy loss during power transmission and improve fuel efficiency. There is also a strong demand for reducing resistance during excavation and soil transport. Generally, medium and small bulldozers have a shorter carrying distance than large bulldozers. If the above-mentioned requirements can be met, the engine output during excavation and soil transport can be used effectively even with blades and traction forces having the same capacity as conventional ones.

As an example of a blade device for increasing the amount of work of this type of work vehicle, for example, the present applicant has previously proposed a completely new blade structure that has not existed in the past by WO 2004/044337 A1 (Patent Document 1). .
The blade disclosed in Patent Literature 1 extends from a central front surface portion, a connecting front surface portion that is bent backward and expands from the left and right end portions thereof, and extends from the connecting front surface portion while being expanded forward. The center front surface portion has a required blade width extending at the left and right perpendicular to the excavation direction, and has a first cutting edge at the lower end, The end front part also has second and third cutting edges at the lower end thereof, the intersection line of the connecting front part and end front part, and the cutting edges of the second cutting edge and the third cutting edge. Is a recessed position in which the front surfaces of the center front surface portion, the connection front surface portion, and the end front surface portion are continuous from the upper end to the lower end. It has a special shape formed on the curved surface.

  Examples of work machines to which the blades of Patent Document 1 are applied include construction / civil engineering machines, and typical construction / civil engineering machines include construction / civil engineering vehicles such as bulldozers, wheel dozers, and motor graders. It is done. The “front view”, “top view”, and “side view” of the blade according to the present invention used in this specification are front view when the blade is grounded to the ground surface at a cutting edge angle with high excavation efficiency. This refers to a top view and a side view.

  The blade has a central front surface part that constitutes a part of the front surface of the blade, and also has a front surface portion on the left and right ends of the blade so as to expand to the front, and thus has the same front surface portion as the conventional blade. However, a connecting front part is disposed between the central front part and the end front part, and the left and right connecting front parts are extended rearward at the left and right end parts of the central front part. It is greatly different from the conventional blade in that the left and right end front portions are extended and extended further forward from the rear end edge of the connecting front portion.

  On the other hand, a blade device having a shape very similar to the blade shape of the present invention is different from the blade device applied to various operations such as excavation, earthing, and leveling as described above. Document 2). The blade device described in Patent Document 2 is applied to a landfill compression work vehicle that compresses while spreading garbage in a garbage disposal site or the like. The shape of the blade is a single piece connecting the left and right end blade parts with the end blade parts that expand and project in the shape of both wings in the vehicle running direction at the left and right end parts as in the conventional U-shaped blade A flat plate-shaped central blade portion, and a rectangular projecting portion at the central portion of the central blade portion that is inclined downward in the middle of the vertical direction and projects in the vehicle traveling direction. Yes. When the lower surface of the projecting portion is placed along the vehicle running surface, the lower end edges of the end blade portion and the central blade portion are also placed along the vehicle running surface.

  Moreover, steel wheels are employed in the traveling device of the compression work vehicle, and dust and the like are compressed by the wheels. The posture when the lower edge of the end blade portion and the central blade portion of the blade device are aligned with the running surface of the wheel in a straight line is the first position, and the posture when the blade is raised and tilted forward When in the second position, dust and dirt are spread horizontally by running the compression work vehicle when in the first position, and between the left and right wheels of the vehicle by the protruding portion in the center of the blade when in the second position. Control the amount of dust and soil sent to the space, that is, limit the height of the dust sent to the space, and through the gap between the lower edge of the end blade portion and the central blade portion and the running surface, the wheel Control the amount of dirt and soil by sending it to the compression area.

  As described above, the blade device disclosed in Patent Document 2 controls the function of diffusing dust and the like and the amount of processing for compressing dust, and at the same time, is a space formed between the left and right wheels that are compression members. It was developed with an emphasis on a function for limiting the amount of dust to be fed into the space so that an excessive amount of dust or the like does not enter and damage the lower surface of the vehicle body. Therefore, when comparing the blade shape of the present invention, which is functionally different from the original, and the blade disclosed in this publication, it can be understood that there is a great difference in the following points.

That is, (1) In order to accumulate and hold a large amount of excavated earth and sand in the central front portion of the blade described in Patent Document 1, the central front surface is continuous from the upper end to the lower end. The central projecting portion of the blade of Patent Document 2 corresponding to the portion protrudes from the middle between the upper and lower ends of the central blade portion to the lower end from the main purpose of eliminating excess dust (2 ) The intersection of each of the pair of left and right connecting front surface portions and the front surface portion of the end portion in Patent Document 1 is located behind the central front surface portion in a top view, and at the same time, the tip of the front surface portion of the end is the lower edge of the central front surface portion. Although it is extended in the vicinity of the extension line, there is no description in the text in Patent Document 2, but a pair of left and right end blades projecting forward from the central blade portion in any drawing Beyond Position is a point that is disposed further forward than the position of the projecting lower edge of the central projecting portion. As described above, these differences are due to the difference in original functions between the blade device of the present invention and the blade device disclosed in the publication.
WO 2004/044337 A1 Publication WO 93/22512 Publication

  In the blade proposed in Patent Document 1, the first cutting edge of the central front surface portion and the tip of the third cutting blade of the front surface portion of the end portion substantially coincide with each other, or the third cutting blade is slightly retracted. I have to. As a result, since the first cutting edge excavates the earth and sand prior to the third cutting edge disposed at the lower end of the front end portion, the excavation force by the connecting front end portion and the front end portion is reduced, and excavation is easy. To. However, in practice, the tip of the third cutting edge may slightly protrude forward of the first cutting edge. In this case, the tip of the third cutting edge is excavated prior to the first cutting edge, but the protruding amount is extremely small, and the substantial excavating force as the entire third cutting edge of the front surface of the end portion is small. Is extremely small as compared with the excavation force of the first cutting edge, and is not affected by the protrusion.

  Therefore, according to the blade described in Patent Document 1, the traction force acting on the third cutting blade is greatly relieved compared to the conventional one, and the resistance force such as excavation resistance and soil carrying resistance is different from that of the first cutting blade. While acting substantially uniformly over the third cutting edge, traction force effectively acts on both the first cutting edge and the third cutting edge, and the soil excavated by the third cutting edge and the The soil excavated by the first cutting edge smoothly joins through the second cutting edge. Moreover, since the intersection area | region pinched | interposed by the connection front part and the edge part front part becomes an earth accumulation part, it becomes possible to carry an efficient and large amount of soil.

  Due to these synergistic effects, the resistance is reduced and the amount of soil per traction can be greatly increased. In addition, the horsepower consumed during excavation and soiling can be greatly reduced, and the maximum amount of excavation and soiling can be obtained with the minimum amount of energy in a short time, thus improving the fuel efficiency of the work machine. The cost per earthwork can be reduced significantly and can be realized.

  By the way, most of the front surface of this type of blade is formed in an arcuate surface that is recessed backward with a predetermined radius of curvature that continues vertically. The blade described in the above-mentioned Patent Document 1 exhibits extremely excellent effects that cannot be expected from the conventional blade due to its special structure, but adopts the front shape of the blade disclosed in this Patent Document 1. From the lower end of the cutting edge fixed to the lower end of the blade when the excavation angle is in the excavation posture with the same radius as the conventional semi-U type blade and the receding angle is about 10 °, the upper end of the blade It was found that when the height was set to 0.5 to 0.7 times, the soil stuck to the front surface of the blade during excavation and the soil did not fall, so that the excavation efficiency was greatly reduced. Furthermore, depending on the design of the central front face, connecting front face and end front face, there are fewer blades in terms of excavation efficiency, although the number is small compared to conventional semi-U blades with the same blade capacity. There are things to do. In addition, especially when turning and turning during soil transport, the soil loaded on the blade slides down from the central front part to the outer connecting front part for a short time during turning, and instantaneously starts from the front part at the end. There was also a situation where everything flowed down.

  The present invention has been made in view of such circumstances. Specifically, the above-mentioned Patent Document 1 has a reduction in the resistance, a significant increase in the amount of soil per traction force, and a reduction in the horsepower consumed during excavation / carrying. Assuming that the maximum excavation and soil transfer can be obtained with a minimum amount of energy and a minimum amount of energy in a short period of time, the excavation of the soil from the blade is good at the time of excavation, and at the same time the conventional semi-U blade is used. The main object of the present invention is to provide a blade device for a work machine that can surely achieve excavation efficiency exceeding that, and that does not fall down when turning and turning during carrying. Other objects will be clarified by the best embodiments of the invention described below.

  The above object is a blade device to be mounted on various working machines, which is the basic configuration of the present invention, and the blade is connected to the central front surface portion and the connecting front surface which is bent and connected to the left and right end portions thereof. The central front surface portion has a blade width W1 extending in the right and left directions perpendicular to the excavation direction, and a first cutting edge at the lower end. The connecting front surface portion and the end front surface portion have second and third cutting edges at their lower ends, and intersecting lines of the connecting front surface portion and the end front surface portion; The intersection of the cutting edges of the third cutting edge is in a rear position with respect to the cutting edge of the first cutting edge in a top view, and the front surfaces of the central front surface portion, the connecting front surface portion, and the end front surface portion are from the upper end to the lower end. A continuous concave curved surface, and each cutting edge extends in a tangential direction from the lower end of each front surface portion. When the cutting edge angle α of each cutting blade is in an excavation posture of 40 ° to 55 ° and the height from the cutting edge of the first cutting blade to the upper end of the central front surface is H in a side view, the radius R2 is (I) It is effectively achieved by the working machine blade device characterized by satisfying the formula: R2 = (0.7 to 1.0) × H. The blade device may have a retaining plate made of a sheet metal material extending in a tangential direction from the upper end of the central front surface portion. In this case, the height H is from the cutting edge of the first cutting blade to the retaining plate. It becomes the height to the upper end of.

According to a preferred aspect, the blade width of the central front surface portion determined by the blade capacity is W1, and the intersection point between the cutting edges of the second and third cutting edges parallel to the extension line of the first cutting edge and the extension line of the first cutting edge. When the interval between the straight line passing through is Wt and the backward bending angle between the cutting edge of the first cutting edge and the second cutting edge is δ, the interval Wt and the backward bending angle δ are expressed by the following equation. (II) and (III) are satisfied at the same time.
Wt> 0.65 × (W1 / 10) (II)
14 ° <δ <30 ° ……… (III)
Here, Wt and W1 may be actual values (mm) or respective reference values (no unit).
More preferably, the crossing angle θ intersecting on the extension line of each cutting edge between the central front surface portion and the end front surface portion may be set to 0 ° <θ ≦ 25 °.

  As described above, the left and right connecting front portions are arranged to extend rearward within the range of the rear bending angle δ in a rearward direction continuously from the central front portion in a top view, and the left and right end front surfaces. Similarly, it is preferable that the portion is arranged so as to extend forward with the crossing angle θ toward the front continuously from the connecting front surface portion in a top view. That is, the connecting front surface portion and the end front surface portion are connected in a V shape or U shape, and further, the second cutting blade and the third cutting blade are formed in a V shape or a U shape. Are connected.

  Furthermore, in the present invention, at least the first cutting edge of the central front surface portion is substantially equal to the blade width W1 at the lower end of the central front surface portion, and the central front surface portion is recessed backward from the lower end toward the upper end. It is preferable that the curved surface is formed and gradually widened. The blade width W1 at the lower end of the central front portion is preferably larger than the inner width between the left and right traveling devices, and the blade width W1 at the lower end of the central front portion is a gauge width that is the distance between the centers of the left and right traveling devices. Should be approximately equal to

  In addition, the second cutting edge is disposed slightly inclined left and right with respect to the first cutting edge, and the third cutting edge is slightly inclined right and left with respect to the second cutting edge. It is preferable that it is arranged. It is desirable that the blade front surfaces of the connection front surface portion and the end front surface portion have the same curved surface as the central surface portion.

Effect

  The external shape of the soil on the blade in the present invention, like the blade disclosed in Patent Document 1, greatly increased from the upper end to the lower end of the central front part and beyond the angle of repose at the central part to the front. It becomes a shape. On the other hand, in the conventional blade, the appearance shape of the soil is a linear planar shape having an inclination angle substantially equal to the angle of repose from the upper end to the lower end of the blade. That is, the present invention can also obtain the maximum excavation and soil carrying amount with the minimum amount of energy in a short time, and the fuel efficiency of the working machine is remarkably improved, and the cost per earthwork amount is the same as in Patent Document 1 described above. Is reduced.

  By the way, after making the proposal of the blade disclosed in Patent Document 1, it was found that there were problems as described above while continuing various test operations. Therefore, as a result of repeating various tests and designs, the cause of the above-mentioned poor soil separation on the blade during excavation, variation in excavation efficiency, and falling soil from the blade during swiveling and turning are as follows. Based on the complicated blade shape unique to the invention, specifically, the front curved surface of the blade and the backward tilting posture of the entire blade are formed in the same manner as in the conventional semi-U type blade, and the blade Depends on the lack of established indicators for objectively determining the optimal shape of the central front face, connecting front face and end front face according to capacity, and the relative proportion of blade width of each front face I knew that.

  In the present invention, it is preferable that the front surfaces of the blades of the central front surface portion, the connecting front surface portion, and the end front surface portion are inclined rearward as in the prior art. During the work, the soil is stuck on the blade, making it difficult to slide down. This is due to the special blade shape of the present invention. In order to avoid this, it is conceivable that the edge angle is set in the same manner as in the prior art, and the front face of each cutting edge extends on the extension of the front face of the lower end of the blade. And, tilting the entire blade backward reduces the contact angle of the soil deposited on the ground with respect to the ground when the inclination angle on the surface of the deposited soil held by the blade, i.e., the angle of repose, is considered to be constant. Conversely, a large amount of soil can be loaded on the blade. Therefore, even when the front surface of each cutting blade is provided on the extension of the front surface of the lower end of each blade, a device for tilting the entire curved surface of the blade itself is required. If this can be achieved, the existing excavation capacity can be secured, and the amount of soil carried and the amount of soil resistance can be greatly reduced, and the horsepower consumed per traction can be greatly reduced, resulting in good fuel efficiency. Performance is obtained.

  In the blade apparatus according to the present invention having the special overall shape as described above, the cutting edge angle α of the cutting edge is set to the same cutting edge angle as that of Patent Document 1, and the receding angle γ is set to 0 °, and a predetermined radius of curvature is set. The upper end of the cutting blade was fixed in the tangential direction of the arc surface at the lower end of the front surface of the blade having an arc surface. According to the test results, the blade front surface has an arc having the same radius of curvature as that of Patent Document 1 (= 0.5 to 0.7 × H, where H is the height from the ground surface to the blade upper end). If a cutting blade is fixed to the lower end of the surface so as to extend in the tangential direction, the blade is inclined backward and the amount of loaded soil is reduced. Therefore, the blade edge angle α is set to a conventional blade edge angle of 50 ° or more in the range of 40 ° to 55 ° as in the smaller patent document 1, and at the same time, the backward inclined posture of the entire blade is maintained. It was. If the cutting edge angle α is further reduced, the excavation efficiency is greatly reduced. However, simply reducing the cutting edge angle α will weaken the force that pushes up the soil accumulated on the blade to the upper side of the blade by newly excavated soil, and the soil tends to stick to the blade during excavation. I learned that the soil resistance increased and the desired load could not be obtained.

  Therefore, in the present invention, in order to avoid a decrease in excavation force, the blade edge angle α is set to 40 to 55 °, and the radius of curvature of the arc surface is larger than the radius of the arc surface of the conventional blade front surface of the same blade capacity. Was also significantly longer. That is, normally, the radius of curvature is set to a length not less than 0.5 times the blade height H calculated from the blade capacity and shorter than 0.7 times. 7 or more and 1.0 or less. If the radius of the arc surface is increased in this way, the soil loaded on the blade by excavation will not stick to the front surface of the blade, and the resistance of the soil will be reduced and it will be pushed upward smoothly. A quantity is obtained. And even if there is a receding angle γ, which is the difference between the cutting edge angle α and the excavation angle β, unlike the case where the excavation angle β is simply excavated, the soil separation is improved. The receding angle γ is desirably in the range of 0 ° to 15 °.

  Further, in the blade device of the present invention having the specific blade shape as described above, the excavation efficiency is determined by the intersection of the blade width W1 of the central front surface portion, the cutting edge of the connection front surface portion, and the cutting edge of the front surface portion of the end portion. And the extension line of the first cutting edge of the central front part (hereinafter referred to as a retraction amount) Wt, behind the cutting edge of the second cutting edge of the connecting front part with respect to the cutting edge of the first cutting edge of the central front part It has been found that it is determined by three parameters of the bending angle δ. The above formulas (II) and (III) are correlation equations of these three parameters. In addition, the backward bending angle δ has an upper limit value and a lower limit value, and the lower limit value defines the lower limit value (%) of the excavation efficiency, for example, a lower limit value for reliably exceeding the excavation efficiency of the semi-U blade. Value. On the other hand, the upper limit value of the rear bending angle δ is an upper limit value for reliably preventing the fall of the soil due to the turning and turning during the carrying.

When the value of the retraction amount Wt corresponding to the blade capacity is determined at the design stage, the optimum value of the rear bending angle δ corresponding to the blade capacity can be selected from the above numerical range. In general, the blade width W1 of the central front portion is preferably set to be approximately equal to the distance (gauge width) between the center lines of the left and right traveling devices of the work vehicle. Further, the total width W of the blade is determined by the blade capacity, and the blade width W1 of the central front surface portion equal to the gauge width WG is determined in the same manner. Thus, the overall blade width, gauge width WG, and blade width W1 are lengths that are changed depending on the blade capacity. If, for example, the total blade width W having a blade capacity of 45 m ³ is used as a reference, the actual total blade width of the central front portion when it is smaller than 45 m ³ is shorter than the blade width W, and when it is larger than 45 m ³ , the center The actual blade width of the front portion is longer than the blade width W.

  In the present invention, the value Wt of the amount of relative retraction up to the intersection of the cutting edges of the connecting front face and the end front face with respect to the cutting edge of the central front face is tested to the actual blade width W1 obtained as described above. Is multiplied by 0.65 / 10 which is a constant obtained by. When the retraction amount Wt is determined, the full width W of the blade is determined by selecting the rear bending angle δ that has the best excavation efficiency and can withstand pushing from the above-described rear bending angle δ. The dimension W4 between the lower end bending point of the center front surface portion and the connection front surface portion and the outer end surface of the end front surface portion is inevitably determined in top view.

  However, the crossing angle θ between the extension line of the cutting edge at the center front surface portion and the extension portion of the blade edge at the end front surface portion is not yet determined here. This crossing angle θ has a very important meaning together with the rear bending angle δ because it forms a soil reservoir formed on the front surface of the bent portion between the connecting front surface portion and the end front surface portion. In addition, the magnitude of the excavation force at the front part of the end, which varies depending on the soil quality at the work site, is also affected. The crossing angle between the connecting front surface portion and the end front surface portion in the earth accumulation portion can be calculated by 180 ° − (δ + θ). In order to maintain this soil holding, θ should be as large as possible. However, in the case of a semi-U type blade having a simpler shape than the present invention, for example, when the soil quality at the site is soft and only a function of the leveling function is necessary, θ is infinitely close to 0 °. On the other hand, when the soil is hard and the side cut function is required, the value of θ needs to be increased to some extent. Therefore, although it is difficult to determine the value of θ uniformly, it can be determined in consideration of the rear bending angle δ according to the function required for the front surface of the end portion. However, it is said that the maximum angle is about 25 ° to ensure the side cut function.

  If this crossing angle θ exceeds 25 °, the load concentrates on the edge of the third cutting edge on the front face of the end, an excessive load is applied during excavation, and the entire cutting edge is not evenly loaded and the cutting edge It may be accompanied by breakage. On the other hand, as described above, the blade device of the present invention often has a leveling function. In that respect, it may be necessary to bring the crossing angle θ close to infinity to 0 °. Considering these comprehensively, it is desirable that the crossing angle θ is greater than 0 ° and not more than 25 °. By the way, depending on how to determine the rear bending angle δ and the crossing angle θ, the ratio of the lengths of the blade widths of the connecting front surface portion and the end front surface portion where the total length is determined inevitably changes. Accordingly, the ratio of the lengths of the blade widths of the connecting front surface portion and the end front surface portion cannot be determined uniformly.

  Further, in the present invention, the blade width at the lower end of the central front face is set to be larger than the inner width between the left and right traveling devices when performing leveling work by forward traveling on the ground where there is no running trace of the traveling device. This is because the minimum necessary width is required for leveling. In particular, when the width of the blade center front surface at the lower end of the center front surface portion is made equal to the gauge width which is the distance between the centers of the left and right traveling devices, the most excellent balance can be obtained in terms of excavation, soil handling and leveling functions.

In general, the main work of the above-described work machine includes work such as excavation, earthing, and leveling, and it is important that these machines are equipped with blades having functions capable of performing different work. The blade of the present invention has a leveling function along with excavation and soil transfer.
Normally, this kind of leveling work requires two points: leveling the ground while excavating the ground and carrying it forward, filling the hole in the middle, and leveling the ground levelly. The In the present invention, when the blade width of the central front portion is increased, so-called leveling function increases. On the other hand, in the present invention, the central front surface portion often protrudes forward from the left and right connecting front surface portions and end front surface portions in a top view. Although the connecting front surface portion and the end front surface portion in the present invention also have a leveling function, most of the functions largely depend on the central front surface portion. Therefore, even in the present invention, it is possible to increase the blade width in the central front surface portion.

  By the way, in this invention, the front-end | tip of the 3rd cutting blade of an edge part front-surface part does not necessarily exist behind the extension line of the 1st cutting edge of a center front surface part, but protrudes ahead rather than the extension line. It also includes. That is, as long as the tip of the third cutting edge on the front surface of the end portion is arranged in the vicinity of the extension line of the cutting edge of the first cutting edge, the first cutting edge is the third cutting edge as in the blade of Patent Document 1. The soil excavated by the cutting blade on the front surface of the end portion and the soil excavated by the first cutting blade of the central front surface portion are smoothly merged via the connecting front surface portion. , The amount of soil can be increased significantly. Further, in the present invention, the wider the blade width of the central front part, the narrower the width occupied by the connecting front part and the end front part in top view.

  In order to reduce the width occupied by the front part of the connection and the front part of the end and to reduce the resistance force such as excavation resistance and soil transfer resistance, the amount of soil transfer can be greatly increased. It is preferable that the length along the lower end of the front part of the part is constant. That is, in order to increase the blade width of the central front part and ensure the required length along the lower end of the connection front part and the end front part, the intersection of the connection front part and the end front part in top view. You will have to reduce the angle to do. As a result, it is inevitably necessary to increase the distance between the cutting edge position of the central front surface portion and the support point of the straight frame that supports the blade.

  When the distance between the cutting edge position of the central front surface and the support point of the straight frame that supports the blade increases in this way, the vehicle is greatly affected by the uneven surface of the ground surface during excavation, and the vehicle pitches back and forth. As a result, the blade swings up and down greatly, and stable excavation by the central front surface portion cannot be performed, and the excavation surface tends to be uneven and cannot be leveled. When these are taken into consideration, it is necessary to determine the blade width of the central front surface portion in consideration of the blade widths of the connecting front surface portion and the end front surface portion as seen from above. In the present invention, the effective digging force per blade width of the first cutting edge of the central front portion is set by setting the blade width of the central front portion substantially equal to the gauge width that is the distance between the centers of the left and right traveling devices. Increases the efficiency of excavation and soiling, and at the same time leveling the ground.

  On the other hand, looking at the blade of Patent Document 2 published internationally, it can be understood that the configuration of the present invention is greatly different from that of the present invention. That is, in the blade disclosed in the above publication, the effective width of the central projecting portion is substantially equal to the distance between the left and right wheels as the compression device, in other words, the distance between the opposing surfaces of the left and right wheels. ing. This is a natural structure in order to prevent a large amount of dust from entering the space formed between the left and right wheels because the function of the central projecting portion is not allowed.

  As a preferred aspect of the blade of the present invention, the left and right connecting front surface portions are arranged to extend rearward at a predetermined angle continuously to the central front surface portion, and the second cutting edge is provided at the lower end. The left and right end front portions are arranged to extend in a forward direction at a predetermined angle continuously to the connection front portion, and have a third cutting edge at the lower end. This point is also different from the blade disclosed in Patent Document 2.

  By the way, in this type of self-propelled working machine, an engine room is often arranged at the front center of the vehicle body, and an operator operates various operation rods behind the engine room. Therefore, the operator's field of view is blocked by the engine room, and the amount of excavated soil deposited on the center front surface cannot be confirmed directly visually.

  On the other hand, even in the present invention, the posture when maximizing the excavation performance of the blade, usually in the front view when the blade is grounded with the edge angle, the central front surface portion, the left and right connecting front surface portions, and When the cutting edges of the cutting edges on the left and right end front parts are arranged on the same straight line, check the amount of soil deposited between the connecting front part and the end front part arranged on the left and right I can only do it. However, the amount of soil deposited on the central front surface portion increases the amount of soil deposited on the central front surface portion in addition to the amount of soil deposited between the connecting front surface portion and the end front surface portion as described above. . Therefore, the amount of soil deposited on the central front surface exceeds a predetermined amount when the operator can confirm the accumulated soil deposited between the connecting front surface portion and the front surface portion of the end obliquely from above. This increases the complexity of blade operation.

  Therefore, according to a preferred embodiment of the present invention, the second cutting blades on the left and right sides in a posture when the blades exhibit the maximum excavation performance, usually in a front view when the blades are grounded with a cutting edge angle. Are arranged with a slight downward inclination with respect to the central first cutting edge, and the third cutting edge is arranged with a slight upward inclination with respect to the second cutting edge.

  By adopting such a configuration, the switching portion between the second cutting blade and the third cutting blade enters the ground in a normal posture, and during excavation, the second cutting blade and the third cutting blade More excavation than before can be obtained. As a result, the amount of soil deposited between the connecting front surface portion and the end front surface portion increases, and the amount of soil deposited on the central front surface portion follows. As a result, even if the operator cannot visually confirm the amount of soil deposited on the center front surface, the amount of soil deposited between the left and right connected front surfaces and the front surface of the end portion can be reduced. By visually checking, it is possible to grasp an appropriate amount of accumulated soil in the central front surface portion, and to perform smooth blade operation.

In the blade of the present invention, the central front surface portion, the connecting front surface portion, and the end front surface portion can be independently formed, and each front surface portion can be continuously formed by welding. By appropriately setting the above, a part can be replaced by a cast product.
Furthermore, according to the present invention, since the width of the cutting edge at the lower end of the front end portion of the end is relatively determined with respect to the width of the cutting edge of the connecting front end portion, it is difficult to determine uniformly. It is preferable that the width is smaller than the width of the blade and is substantially equal to the width of the cutting blade at the lower end of the connecting front surface portion. When the width of each front part is set to the dimensional relationship, the amount of soil to be raised and held along each blade front surface of the connection front part and the end part front part can be optimized, and the soil amount with respect to the central front part can be optimized. This is preferable because the resistance can be reduced. However, in consideration of excavation efficiency, as described above, the retreating amount Wt to the intersection of the second cutting edge of the connecting front face and the third cutting edge of the end front face and the first cutting edge of the central front face and the connecting front face In many cases, there is a difference between the blade widths of the connecting front surface portion and the front surface portion of the end portion because of the restriction of the backward bending angle δ between the first cutting edge and the second cutting edge.

  In the present invention, the crossing angle at which the center front surface portion and the end front surface portion intersect on the extension line of each cutting edge is set to 0 ° to 25 °. In particular, when importance is attached to the side cut function, it is desirable to set within a range of 18 ° to 25 °. If this crossing angle θ is 18 ° to 25 °, it is possible to secure an optimum amount of soil to be loaded on each blade front surface with the connecting front surface portion and the end front surface portion. The resistance of the soil moving from the front part toward the connecting front part can be reduced, and if it is less than 18 °, the side cut function is lost. However, as described above, the function of the front surface of the end portion is not limited to the side cut function. For example, when the leveling function is desired for the third cutting edge of the front surface of the end portion, the crossing angle θ is 0 ° as much as possible. It may be close to. Further, according to the present invention, when the cutting edge angle between the front surface and the ground when the cutting edge of each cutting edge is on the ground is set to 40 ° to 55 °, the minimum amount of excavation / soil carrying energy and the maximum amount of soil are effective. Can be obtained.

  Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The blade device of the present invention can be used as a work attachment equipped in various work machines. Examples of the working machine applied to the present invention include a construction / civil engineering machine. In this embodiment, a bulldozer (not shown) will be described as an example of a construction / civil engineering machine, but the present invention is not limited to this, and includes, for example, construction / civil engineering vehicles such as a wheel dozer and a motor grader. It is.

  As shown in FIGS. 1 to 5, a blade device 10 according to a typical structural example of the present invention includes a blade front surface portion 11 that is curved in a concave shape up and down. In this embodiment, which is one of the preferable modes, a part of the integrated casting structure is provided, and the other part is a sheet metal structure. The present invention naturally includes the case where the entire blade proposed by Patent Document 1 is made of sheet metal.

  Since the front surface portion of the blade device 10 of the present invention is based on the basic shape of the front surface portion of the blade device disclosed in Patent Document 1, the specific functions and effects based on the basic shape are the same as described above. This is equivalent to the action and effect described in Document 1. Accordingly, the description of these functions and effects will be limited to a simple description, and a detailed description will be given centering on the specific structure provided by the present invention and the corresponding specific functions and effects. The blade 11 of the blade device 10 according to the present invention has the basic structure shown in FIG. That is, the blade 11 has a curved surface whose front surface is curved in a concave shape. The blade 11 has a central front surface portion 12 having a linear first cutting edge 15 at the lower end, and a second extending continuously extending from the first cutting edge 15 in a backward direction with a predetermined rear bending angle δ. A pair of left and right connecting front face portions 13 having cutting edges 16 and the outer ends of the second cutting edges 16 are continuously connected to each other and expanded with an extension line of the first cutting edges 15 and a predetermined crossing angle θ. It is comprised by the left-right paired edge part front-surface part 14 which has the linear 3rd cutting blade 17 extended in the direction.

  In the blade apparatus 10 of the present invention, as shown in FIG. 5, the tip of the third cutting edge 17 of the end front part 14 is substantially extended from the side edge of the central front part 12 and the first cutting edge 15 as viewed from above. Although it is arranged on the line, it may be made to recede from the extension line or slightly protrude forward from the extension line. The point is that the connecting front surface portion 13 is bent and extended while expanding to the rear continuously from the left and right side edges of the central front surface portion 12 and forward from the outer side edge portions of the left and right connecting front surface portions 13. It only needs to be bent while being expanded and continuously provided. However, the intersection line of the connecting front surface portion 13 and the end front surface portion 14 and the intersection C of the second cutting edge 16 and the third cutting edge 17 are more than the left and right side edges of the central front surface portion 12 and the first cutting edge 15. Must be in the rear position.

  Here, in this embodiment, the difference from the above-mentioned patent document 1 is that in this embodiment, the left and right end regions B of the central front surface portion 12, the connecting front surface portion 13 and the end front surface portion 14 each have a back surface portion. In addition, the central main area A of the central front surface portion 12 includes a front plate 106 and a back support member 107 which will be described later, which are integrated by welding. This is the point. Here, at least the central main region A of the front plate 106 of the central front surface portion 12 according to the present embodiment is made of sheet metal made of rolled steel, and the back support member 107 corresponding to the front plate 106 is partially made of sheet metal. For the parts that require strength, a casting for exclusive use of the back support member that is cast separately from other integrally cast parts is used.

  Further, in the present embodiment, in order to carry more soil, the trapezoidal sheet metal member 18 including the cast portion along the upper edge of the central front surface is welded or the like so that the tangent to the central front surface is seen in a side view. Extends as a retaining plate in the direction. The rectangular portion at the center of the sheet metal 18 has a ground contact portion as a flat surface, and the left and right triangular portions have a lattice portion having a plurality of lattices 18a. This lattice portion is provided for the operator to visually recognize the amount of soil in front of the left and right ends of the blade device when working the working machine. In the present embodiment, the sheet metal member 18 is attached in the tangential direction of the central front portion in a side view, but may be inclined forward or backward from the tangential direction in the same side view. Note that the height H of the blade device includes the height of the sheet metal member 18 when the sheet metal member 18 is provided in a tangential direction of the center front surface portion or tilted forward with respect to the tangential direction in a side view, but includes a rearward tilt. The height of the sheet metal material 18 is not included.

  In this embodiment, as shown in FIGS. 1 and 2, the central front surface portion 12 having a substantially inverted trapezoidal overall shape in front view is divided into a rectangular divided central portion 12a of the central main region A and its left and right end regions B. It divides into three into a substantially inverted triangular divided end 12b. A connecting front surface portion 13 is connected to the divided end portion 12b by expanding it rearwardly in a V shape or U shape with a required rear bending angle δ as described later. The end front surface portion 14 is connected to the center front surface portion 12 so as to expand forward in a V shape or U shape with an extension line of the lower end cutting edge of the central front surface portion 12 and a required crossing angle θ. At this time, the front surfaces of the central front surface portion 12, the connection front surface portion 13, and the end front surface portion 14 are curved in a concave shape with the same curvature in the vertical direction on the entire surface or a part of the entire front surface.

  Further, in the present embodiment, as described above, the split end portion 12b, the connecting front surface portion 12 and the end front surface portion 14 of the central front surface portion 12 having left and right bent surfaces and upper and lower curved surfaces on the front surface, The integral casting portion 101 is configured by integral casting including the back support portion 107. On the other hand, the rectangular divided central portion 12a of the central front surface portion 12 is constituted by a sheet metal portion 105 made of sheet metal for a front plate 106 which is a main component member.

  The rectangular divided central portion 12a includes the front plate 106 and a back support member 107 described later. The front plate 106 is made of a sheet metal having a horizontally long rectangular shape when viewed from the front shown in FIG. 2, and is directed from both ends of the upper bottom portion of the central front portion 12 having a substantially inverted trapezoidal shape to the lower bottom portion as described above. This is a plate material constituting the central rectangular portion when cut vertically, that is, the front surface of the rectangular divided central portion 12a. The cut both-side inverted triangular portion, which is the remaining portion, is integrally cast together with the connecting front surface portion 13 and the end front surface portion 14 including the back surface supporting portion to constitute the divided end portion 12b. In the present specification, an area including the front plate 106 in the central front portion 12 made of sheet metal, the sheet metal member 18 extended to the upper edge of the center plate 18 and the back support member 107 is referred to as a sheet metal portion 105. An integrally cast region including a back support portion 103 (to be described later) of other blade portions excluding the sheet metal portion 105 is referred to as an integral casting portion 101. As described above, when the central front surface portion 12 is divided into the rectangular divided central portion 12a and the triangular divided end portion 12b on the vertical line, the front surfaces of the rectangular divided central portion 12a and the triangular divided end portion 12b are smoothly curved surfaces. At the same time, the connecting line becomes a straight straight line along the curved surface when viewed from the front, so that the assembly process enables automatic welding using a welding robot that does not rely on human hands.

  4 and 5 show a schematic configuration when the bulldozer 1 is equipped with the blade device 10 according to the present embodiment. The blade device 10 is arranged at the front portion of the bulldozer 1 and has a pair of lift frames 3 whose proximal ends are pivotally supported by the central portion of the crawler type traveling device 2 and extend forward, and whose proximal ends are at the central portion of the lift frame 3. A tilt cylinder 4 pivoted and extended forward (hydraulic), a lift cylinder 6 having one end of a cylinder body pivoted on a side wall of an engine room 5 disposed in front of the cab (hydraulic), and the lift frame The front end of the strut arm 7 is pivotally attached to the base 3 and extends obliquely to the center of the rear surface of the blade 11 when viewed from above. For this reason, a bracket for supporting a lift frame or the like is usually protruded rearward from the back support member of the blade by welding. In this embodiment, as shown in FIGS. 11 and 12, in the pair of left and right integral casting portions 101 of the blade 11, the front end of the lift frame 3 is rearward from the outer lower end corner portion of the back surface portion 103. Left and right first brackets 25a for supporting the parts are integrally cast and project, and a second end for supporting the front end of the (hydraulic) tilt cylinder 4 is provided above the bracket 25a of the back surface part 103. The bracket 25b is integrally cast and protrudes backward.

  The front surface of the connecting front surface portion 13 in the present embodiment has a substantially triangular shape or a trapezoidal shape that is gradually widened from the upper end to the lower direction, opposite to the central front surface portion 12, and as shown in FIG. When viewed from the front, the one side edge is integrated with the connecting side end edge of the central front surface portion 12 and is bent in the vertical direction. In addition, the front surface of the end front surface portion 14 has the same width from the upper end to the lower side in a front view, and is a vertically long, substantially rectangular shape curved in a concave shape having the same curvature as the central front surface portion 12 and the connecting front surface portion 13. Is formed. Here, in the present embodiment, the extension line at the lower end of the central front surface portion 12 substantially coincides with the tip position of the end front surface portion 14. The overall shape of the blade 11 has a rectangular shape with a long left and right width when viewed from the front. As shown in FIG. 1, these front surface portions 12, 13, and 14 are connected in a V shape in which the connection front surface portion 13 extends rearward from both ends of the central front surface portion 12. Are widely expanded in a V-shape from the outer end of each connecting front surface portion 13 toward the front. Although the V-shape is shown in the illustrated example, the shape is not necessarily limited to this shape. For example, a U-shape having a wide open end may be used. Here, the front view is a front view when the cutting edge is grounded at a cutting edge angle α (equal to the excavation angle β in the present embodiment) with respect to the ground as shown in FIG. Say.

  The first cutting edge 15, the second cutting edge 16, and the third cutting edge 17 are made of a tough material that has excellent wear resistance and is not easily damaged, such as boron steel. In the preferred form of the arrangement of the first cutting edge 15, the second cutting edge 16, and the third cutting edge 17 as described above, the first cutting edge 15 precedes the second and third cutting edges 16, 17. Like to dig. Since the excavation by the first cutting edge 15 breaks up the surrounding ground in advance, the substantial excavation force necessary for the second and third cutting edges 16 and 17 is greater than the excavation force of the first cutting edge 15. And at the same time, a smaller amount of excavation than the first cutting edge 15 is achieved. As shown in FIG. 3, a plurality of vertical plate ribs 26 that reinforce each of the cutting blades 15 to 17 are provided at portions corresponding to the first to third cutting blades 15 to 17 of the lower end plate portion of the blade 11. 26 extend in the front-rear direction, and the front ends of the vertical plate ribs 26,... And the rear surfaces of the first to third cutting edges 15-17 are screwed together.

  In each of the front surface portions 12 to 14 of the blade 10 according to the present invention, as shown in FIG. 6, an angle (cutting edge angle) α formed between the front surface of the first cutting blade 15 and the ground and the lower end portion of the central front surface portion 12. A receding angle γ, which is a difference between an angle (excavation angle) β between the extension line of the front surface and the ground, is set to 10 ° as in Patent Document 1, and the curvature radius R1 of the blade front surface is also the same as in Reference Document 1. did. Incidentally, the blade edge angle α of the blade described in Patent Document 1 is 46 °, the excavation angle β is 36 °, and the receding angle γ is 10 °. For example, the excavation angle of a semi-U type blade is 52 °. The curvature radius R1 at this time is (0.5 to 0.7) × blade height H, as in the conventional blade of this type. In this way, when the same numerical values as in the past are adopted, because of the complicated blade shape unique to the present invention, the soil on the blade at the time of excavation does not cling to the blade front and slides down, excavation efficiency and the amount of sediment Is significantly reduced. Therefore, the receding angle γ was set to 0 ° without changing the blade edge angle α and the curvature radius R1 of the blade front surface. That is, the excavation angle described in Patent Document 1 is adjusted to the cutting edge angle, and the blade height and the radius of curvature of the entire blade surface are not changed, and are fixed to the lower ends of the central front surface portion 12, the connecting front surface portion 13 and the end front surface portion 14. The leading ends of the first to third cutting edges 15 to 17 provided are projected along the extended surfaces of the front surface portions 12 to 14 without being retracted from the front surface portions 12 to 14. As a result, as shown in FIG. 7, the backward inclination of the entire blade is reduced, the front part rises, and the soil does not move up the blade front during excavation, and the amount of soil is greatly reduced. It was.

  FIG. 7 shows a blade when the receding angle γ is set to 0 ° as described above and the first cutting edge 15 is extended in the tangential direction of the lower end of the front circular arc surface of the central front surface portion 12 having the same radius of curvature R1 as before. 11 shows a backward tilt posture. On the other hand, FIG. 8 shows the backward tilting posture of the blade 11 according to the present embodiment, and the front surface portions 12 to 14 are set so that the receding angle γ of the first to third cutting edges 15 to 17 is 0 ° as in FIG. It extends from the lower end of the front. At this time, in this embodiment, the curvature radius R2 of the front arc surface of each of the front surface portions 12 to 14 is larger than the curvature radius R1 of the arc surface shown in FIG. To 1.0) × H. In both figures, the height H from the cutting edge of the first cutting edge 15 to the upper end of the blade is the same height. As can be understood from these drawings, even if the cutting edge angle α is the same, the blade 11 according to the present embodiment is more than that shown in FIG. 7 because the radius of curvature R2 of the arc surface is increased as shown in FIG. Thereafter, the inclination is higher than that of the blade 11 having a small radius of curvature. As a result, the amount of soil carried on the blade is significantly increased over the conventional blade with a general shape, and the soil falls smoothly from the front of the blade during soil removal, and the soil adheres to the front of the blade. Nothing remains, and excavation efficiency has improved.

Here, the blade height H is determined by the blade capacity Q. The blade capacity is a standard one-time work amount when pressing earth or sand with a blade, and is a calculated value based on a calculation formula defined by a standard or the like. That is, the blade capacity Q is set according to the vehicle size, and in the case of a straight blade having the simplest shape (as a rule, a horizontally long rectangle) between the blade capacity Q and the blade height H, Q = W × The relationship of H ² (W is the full width of the blade) is established. Therefore, the blade height H can be determined naturally when the blade capacity Q and the blade full width W are determined. Further, the following relational expression (IV) is substantially established between the blade capacity Q and the dimensions of each part of the blade having the special shape of the present invention.

Q ≒ j × {Wt (W1 + W2 · cosδ + W3 · cosθ) × H + 2 × (1.4W- 0.3W) × H 2/2} ......... (IV)
Here, j is a coefficient based on the circular arc surface, H is the blade height, W is the full width of the blade, W1 is the blade width of the central front portion, W2 is the blade width of the connecting front portion, W3 is the blade width of the end front portion, Wt is the distance to the back intersection of the connecting front part and the front part of the end part, δ is the bending angle of the connecting front part with respect to the central front part, and θ is the extension line of the cutting edge of the central front part and the cutting edge of the front part of the end part Is the crossing angle.

  9 and 10 are explanatory diagrams showing the calculation principle of the blade capacity Q of the blade device 10 according to the present invention. FIG. 9 is a projected view of the blade 11 of the present invention and the soil carried forward of the blade, and FIG. 10 is a side view of the blade 11 of the present invention and the soil carried forward of the blade. In general, it is said that the inclination angle (rest angle) of the soil surface is around 30 °. When calculating the blade capacity, SAE standard J1265 MAR88 is 26.5 ° (the tangent of the repose angle is 0.5). It has established. Therefore, the blade capacity Q takes into consideration the angle of repose, and takes into account the volume Q1 obtained by multiplying the projected area of the blade 11 by the blade height, and the amount of soil that flows forward from the front end of the blade and flows in the left-right direction. The capacity is obtained by adding the volume Q2 obtained by multiplying the projected area of the obtained soil by the blade height H. The first half of the above formula (IV) is the volume Q1 deposited on the blade, and the second half is the volume Q2 of the carrying soil in front of the blade. From this formula (IV), if the blade capacity is determined, the blade height H is also determined.

  As described above, in order to reduce the slip resistance between the soil accumulated on the ground surface in front of the blade during the soil carrying work and the ground surface, the amount of soil in contact with the ground surface may be reduced. As shown by a solid line and a virtual line in FIG. 11, the inclination angle (repose angle) of the front surface of the deposited soil when it is carried by the blade device is constant. In order to reduce the amount of soil in contact with the ground surface, the blade tip of the blade device 10 is as far as possible so that the distance between the blade tip and the soil tip in contact with the ground surface is L2 to L1. It is preferable to shift the hatched area by the slanting line shown by the solid line and the imaginary line in the figure from S2 to S1. FIG. 11 is an explanatory diagram schematically showing a change in slip resistance between soil and ground deposited on the ground surface in front of the blade based on the blade posture. In the figure, a solid line indicates the blade device 10 according to the present invention, and a virtual line indicates a conventional blade. Here, the curvature radius of the front curved surface of both blades is R1 for the conventional blade, R2 for the blade of the present invention is larger than R1, and the blade edge angle α (= β) is constant.

  As described above, since the front surface of the soil deposited on the ground surface has a constant inclination angle according to the soil quality, the blade edge angle α and the receding angle γ (0 ° in FIG. 11) are constant, and the curvature radius of the blade front surface is constant. By enlarging, it is possible to increase the amount of soil deposited on the blade and reduce the contact area between the soil deposited on the blade front surface and the ground surface.

  At this time, the contact length L1 of the deposited soil of the blade device 10 in the present embodiment is reduced by about 10% with respect to the contact length L2 of the normal accumulated soil deposited on the ground surface in front of the cutting edge. The amount of sediment is greatly reduced. On the other hand, during the excavation / soil, the accumulated soil in front of the blade portions 12 to 14 can be loaded in large quantities on the front surface of each blade, and the so-called holding amount increases. As a result, soil resistance and the like can be greatly reduced, so that the horsepower consumed per traction force can be greatly reduced, and good fuel efficiency can be obtained.

  Incidentally, in the present embodiment, since the retraction angle γ is set to 0 °, which is the smallest, it is easy to mount the cutting blade. However, when the blade has a curved surface similar to the conventional one and the blade edge angle α is not changed, the blade The rise of 11 becomes too large, and the amount of soil fall becomes intense. Therefore, as described above, the backward inclination posture of the blade can be increased by changing the radius of curvature of the arc surface of the blade front surface from the normal R1 to R2 larger than that, and at the same time, the soil resistance is reduced and the amount of excavation is reduced. In addition, the amount of soil transport can be equal to or more than usual.

  In addition, since a large amount of soil can be deposited on the front surface of the blade 11 as described above, a good balance of the ground pressure before and after the vehicle body is obtained, power loss such as shoe slip is reduced, and high traction force is obtained. It is done. In the present embodiment, the trapezoidal sheet metal member 18 is inclined upward from the end of the arc surface of the upper end portion of the blade 11, and a large number of lattices 18a aligned in the left-right direction are provided at both ends thereof. Forming. As a result, of the soil accumulated on the front surface of the blade, the excess soil spills from the gap between the lattices 18a formed on the left and right sides of the sheet metal member 18 to the left and right, beyond the upper ends of the blade portions 12 to 14 and rearward. Spilling out is prevented and at the same time the amount of soil at the upper end of the blade is maintained at an appropriate amount. Further, the excavated soil is not pressed against the blade front surface, so that the soil removal during the soil removal is improved, and the soil removal performance is improved. In addition, it is preferable that the cutting edge angle α formed by the front surface and the ground when the cutting edges of the cutting blades 15 to 17 are on the ground is about 40 ° to 55 °. As a result, the minimum amount of excavation / carrying energy and the maximum amount of soil can be effectively obtained.

  As described above, the excavation efficiency varies depending on the cutting edge angle α. However, according to the inventor's test, the lower end blade width W1 of the central front face 12 and the rear of the second cutting edge 16 with respect to the first cutting edge 15 are described. The bend angle δ and the distance between the connecting front surface portion 13 and the intersection C of the respective edge tips of the end front surface portion 14 that intersect the extension line of the first cutting edge 15 at the rear of the extension line (hereinafter referred to as the retreat amount). ) It is known that Wt greatly affects.

  FIG. 12 shows the result of the test, and the excavation efficiency corresponding to the change in the blade width W1 at the lower end of the central front surface portion 12 is bent backward of the second cutting edge 16 with respect to the first cutting edge 15. Determined by the correlation between the backward bending angle δ and the retraction amount Wt between the extension line of the first cutting edge 15 and the intersection C between the cutting edges (16, 17) of the second and third cutting edges. Shows that However, although FIG. 12 is based on a semi-U type blade having a shape closest to the blade device of the present invention, it can be said that other models have the same correlation in effect.

  The horizontal axis in the figure shows the blade width W1 as the gage width of the vehicle body (in the bulldozer, the crawler belt center length) is 10 (no unit), and shows the change in the length with reference to this. In addition, the vertical axis of the figure shows the change in excavation efficiency. The excavation efficiency of the semi-U type blade attached to a standard gauge width is assumed to be 100%. The change in excavation efficiency (%) by the blade of the present invention when equal is shown. In the figure, a group of curves indicated by a one-dot chain line indicates a change in excavation efficiency according to a change in blade capacity when the rear bending angle δ is changed. On the other hand, a straight line group indicated by a broken line is obtained when the retraction amount Wt between the extension line of the first cutting edge 15 and the intersection C between the cutting edges 16 and 17 of the second and third cutting edges is changed. The change of the excavation efficiency according to the change of the blade width W1 is shown. Here, Wt is a unitless coefficient, and a value obtained by multiplying this by a conversion coefficient is an actual value. Note that a numerical value determined by the vehicle body side or blade device other than the gauge width may be used as a conversion factor.

  Accordingly, when designing the blade device 10 of the present invention having the blade width W1 of the central front surface portion 12 determined by the desired blade capacity, the dashed-dotted straight line group and the broken line group are on the vertical line passing through the blade width W1. If the backward bending angle δ and the retraction amount Wt corresponding to each straight line at the time of intersection are employed, a desired excavation efficiency can be obtained. Based on this figure, when the blade width W1 of the central front surface portion 12 is 10 (central portion of the horizontal axis), for example, excavation efficiency exceeding a semi-U type blade having the same full blade width is realized. If the backward bending angle δ is approximately 16.2 ° and the retraction amount Wt is 0.65, excavation efficiency equivalent to that of a semi-U blade can be obtained.

That is, when the blade width W1 of the central front surface portion 12 is 10, if the rear bending angle δ is 16 ° and the retraction amount Wt is 0.65, the same excavation efficiency as that of a semi-U type blade having the same blade capacity is secured. The backward bending angle δ is set to be larger than 16 ° and the backward movement amount Wt is set to be larger than 0.65, and each one-dot chain line having the backward bending angle δ of 16 ° or more and the backward movement amount Wt is 6.5 or more. Are set as the rear bending angle δ and the retraction amount Wt at the point where the broken line intersects on the vertical axis passing through the blade width W1, it exceeds the semi-U blade corresponding to the intersection C between the dashed line and the broken line. Drilling efficiency can be realized. That is, the above-described formulas (II) and (III)
Wt> 0.65 × (W1 / 10) (II)
14 ° <δ <30 ° ……… (III)
If the above are satisfied at the same time, the blade shape that is the most efficient and less soiled when pushed is obtained. Incidentally, in the illustrated example (◆), when the blade width W1 is set to 10 as a reference value, if the rear bending angle δ is set to 20 ° and the retraction amount Wt is set to 0.8, the excavation efficiency becomes 122%. To increase.

  However, the upper limit of the backward bending angle δ and the retraction amount Wt cannot be determined only by the correlation diagram of FIG. By the way, according to other tests, when pushing by turning, depending on the turning radius, the soil loaded on the front surface of the blade 11 within tens of seconds passes through the connecting front part 13 and the front part of the end part. It flows down from 14 and instantly the soil is zero. When the cause was pursued, it was found that the rear bending angle δ was one of the major causes. That is, when the backward bending angle δ is set to 30 ° or more, the soil is slipped off. Therefore, in the present invention, the value of the retraction amount Wt is larger than the value obtained by multiplying the blade width W1 at the lower end of the central front surface portion 12 determined in advance by the blade capacity by 0.65 / 10, and 16 ° or more and 30 °. The backward bending angle δ that provides the highest excavation efficiency within the following range is determined from a correlation diagram prepared in advance.

  On the other hand, in the blade device 10 according to the present invention, since the overall blade width W and the blade width W1 of the central front surface portion 12 are determined by the blade capacity and the size of the vehicle, the connecting front surface portion 13 that intersects and is in the retracted position. The straight line distance between the front end of the front end and the front end of the front end portion 14 is inevitably determined. However, although the linear distance connecting the front end of the connecting front face 13 and the front end of the end front face 14 is determined, either of the blade widths W2 and W3 at the lower ends of the connecting front face 13 and the end front face 14 is increased. I can't decide what to do. This is because, as shown in FIGS. 13A to 13C, for example, the distance between the extension line of the cutting edge of the central front face 12 and the intersection C between the cutting edges of the connecting front face 13 and the end front face, that is, When the retreat amount Wt and the linear distance W4 connecting the front end of the connecting front portion and the front end of the end portion front portion 14 are constant, the above rear where the excavation efficiency is the highest and the amount of falling soil when turning and turning can be reduced The change of the length ratio of each blade width W2 and W3 in the lower end of the connection front surface part 13 and the edge part front surface part 14 when the bending angle (delta) and crossing angle (theta) are changed is shown.

  As can be understood from this figure, the length ratio of the blade widths W2 and W3 at the lower ends of the connecting front face portion 13 and the end front face portion 14 cannot be defined, but the third cutting edge 17 of the end front face portion 14 can be defined. When the length in the blade width direction is longer than that of the second cutting edge 16 of the connecting front surface portion 13 ((c) in the figure), the side cut amount is large and the end is opposite to the case of the semi-U type blade. The amount of soil flowing out from the front part 14 to the side is reduced, and the amount of soil carried by the connecting front part and the end front part is increased. On the contrary, when the length in the blade width direction of the third blade edge 17 of the end front surface portion 14 is shorter than that of the second blade edge 16 of the connection front surface portion 13 ((a) in the figure), the side cut amount is small. The amount of soil discharged from the end front part 14 to the side is reduced. An ideal aspect is a state in which the amount of soil at the center front part and the amount of soil at the front part of the end and the front part of the connection are balanced, as shown in FIG. This is when the lower end blade widths W2 and W3 of the front face portion 13 and the end face front portion 14 are equal. As described above, the restriction that the length of the lower end blade widths W2 and W3 of the connecting front face portion 13 and the end front face portion 14 should be increased is that the retraction amount Wt, the rear bending angle δ, and the intersection. Based on the three parameters of the angle θ, it is determined in consideration of the balance between the function required for the end front part 14 and the carrying function of the soil.

  14 to 16 are sectional views of the blade 11 taken along arrows XIV-XIV to XVI-XVI in FIG. As can be understood from these drawings, the front surface of the blade 11 according to the present embodiment is formed in a curved surface that is recessed backwards between the upper and lower sides inclined backward with the lower end edge of the central front surface portion 12 as the center line. The blade width of the front surface of the central front surface portion 12 is gradually widened from the lower edge to the upper edge in the order of W1-1, W1-2, and W1-3. In this way, when the blade width is gradually increased with the central front surface portion 12 facing upward, the first to third cutting blades 15 to 17 of the central front surface portion 12, the left and right connecting front surface portions 13, and the left and right end front surface portions 14. The soil excavated by (1) sequentially pushes the central front surface portion 12 upward through each curved surface and bending line. At this time, the center front surface portion 12 gradually increases in width as it goes upward, so that it is possible to receive a lot of soil, and it may be a curved surface as compared with a simple rectangular front surface portion. Helps to hold a large amount of soil.

  17 and 18 show the overall shape of the pair of left and right integrally cast portions 101. As can be understood from the figure, the integral casting portion 101 is formed in a shape in which the left and right sides are symmetrical. The integral casting part 101 according to the present embodiment has the front plate part 102 on the front side and the back part 103 and the first and second brackets 25a and 25b on the back side. The front plate portion 102 is formed to have the same thickness throughout. However, in this front plate part 102, only the upper edge of each bent joint portion of the end triangular part 12b of the central front part 12, the connecting front part 13 and the end front part 14 is different from the other parts. Also, the plate thickness is increased to increase rigidity and strength (see FIGS. 17 to 21).

  On the other hand, as shown in FIGS. 17 and 18, the back support part 105 of the integral casting part 101 has first and second rectangular cylinders that are long to the left and right in the rear view, respectively, near the center and lower end of the upper part. Two rear support portions 103a and 103b are protruded rearward. A space between these back support portions 103a and 103b is reinforced by a reinforcing column or the like, and the inside thereof is a hollow portion that communicates to the left and right for weight reduction. The vertical cross-sectional shape of the hollow portion is changed in accordance with the bent joint portion of the front plate portion 102. In particular, at the casting position of the first bracket 25a, the cross-section of the hollow portion is minimized to ensure rigidity and strength. ing.

  That is, FIG. 19 is a cross-sectional view taken along the line XIX-XIX in FIG. 2, and this cross-sectional view is taken along a bending line in each front plate portion 102 of the connecting front face portion 13 and the end front face portion 14. A cavity section is shown. FIG. 20 is a cross-sectional view taken along the line XX-XX in FIG. 3, and taken along a vertical line passing through an intermediate portion of the pair of left and right first brackets 25 a formed at the right end portion in front view. A cross section is shown. FIG. 21 is a cross-sectional view taken along the line XXI-XXI of FIG. 3 and shows a cross section of the cast part close to the boundary line between the integrally cast part 101 and the sheet metal part 105.

  As can be understood from these drawings, the hollow portion is a boundary portion between the connecting front surface portion 13 and the end front surface portion 14, and the interval between the lower end portions of the front plate portion 102 and the rear support portions 103a and 103b is reduced. Between the lower end portions of the front plate portions 102 and the rear support portions 103a and 103b of the left and right divided end portions 12b and 12b of the central front face portion 12 that is the narrowest and the lower end portion of the front face plate portion 102 projects most forward. The interval is the widest. Further, the outer end surfaces of the left and right integral casting portions 101 are arranged on the outer sides as shown in FIG. 22 in order to secure the rigidity and strength of the end portions of the cylindrical back support portions 103a and 103b. A shaft hole 25a ′ of the bracket 25a, an “inverted oblique L” -shaped opening 103b ′, and a rectangular opening 103a ′ are formed thereabove to block all other portions with a required thickness. .

  On the other hand, the sheet metal part 105 includes a rectangular divided central part 12a of the central front part 12, and as shown in FIGS. 2 and 3 and FIGS. 23 to 26, the front plate 106 obtained from a single sheet metal and A back support member 107 made of a sheet metal and a cast product is provided on the back surface of the face plate 106 by welding. The back support member 107 is an upper end edge of a cylindrical first back support portion 103a formed on the upper portion of the integral casting portion 101 from the upper end edge of the blade device 10 in the rear view of the blade device 10 shown in FIG. Until the central front surface portion 12 is between the first sheet metal portion 107a made of a flat trapezoidal sheet metal that is welded at an angle and the cylindrical upper rear support portions 103a of the pair of left and right integral casting portions 101. A space between a second back support member 107b connected by welding with a central rectangular portion interposed therebetween, and the first back support portion 103a and a second back support portion 103b disposed below the first back support portion 103a. A fourth back connecting the third back support member 107c made of a sheet metal that closes the left and right ends of the blade 11 by welding and the left and right cylindrical second back support portions 103b by welding. Composed of a support member 107d.

  Here, the first and third back support members 107 a and 107 c are made of sheet metal, and a plurality of reinforcing ribs (not shown) are provided between the first and third back support members 107 a and 107 c and the front plate 106. Is intervening. The second back support member 107b is formed of a single cast product having a U-shaped cross section that is elongated in the left-right direction, and the fourth back support member 107d is a left split member 107d-2 as shown in FIGS. The casting product is divided into a central divided member 107d-1 and a right divided member 107d-3. The central dividing member 107d-1 is formed of a block body having a U-shaped cross section, and as shown in FIGS. 17 and 18, a fourth bracket 25d for supporting one end of the strut arm 7 is projected rearward at the central portion. A plurality of reinforcing ribs 107d-1 ′ are cast at the same time between the inner wall surfaces. Similarly to the central dividing member 107d-1, the end dividing members 107d-2 and 107d-3 arranged on the left and right sides have a plurality of reinforcing ribs 107d-2 ′ and 107d-3 ′ between inner wall surfaces. It consists of a letter-shaped block.

Now, the blade apparatus 10 of this embodiment which consists of the above structural members is assembled as follows.
First, the inner end face of the front plate portion of the pair of left and right integral casting portions 101, 101 and the left and right end surfaces of the rectangular front plate 106 of the central front face portion 12 are brought into contact with each other, and the three are integrated by welding. Since the welding line at this time is on a vertical line when viewed from the front, welding can be easily performed by the welding robot when each member is positioned. Prior to this welding, side plates 108 having front and rear widths extending forward from the curved front end edge of the outer end surface are integrally attached to the outer end surface of the integral casting portion 101. The side plate 108 has a function of holding the soil and preventing the falling from the blade side part and reinforcing the end front part 14.

  Various back support members 107 are integrally assembled to the back surface of the blade 11 thus manufactured by welding. After the assembly, the pair of left and right shown in FIGS. 3 and 4 is straddled across the left and right divided members 107d-1 and 107d-3 of the third back support member 107c and the fourth back support member 107d. A crescent-shaped third bracket 25c for supporting the piston rod ends of the two sets of (hydraulic) lift cylinders 6 is fixed by welding. The first to third cutting edges 15 to 17 are fixed in the same manner as in the prior art along the lower ends of the central front surface portion 12, the connecting front surface portion 13 and the end front surface portion 14 of the blade 11 assembled in this way. Thus, the blade device 10 of the present invention is completed. The first cutting edge 15 has a flat linear shape along the lower end of the central front surface portion 12. Therefore, it becomes possible to use it effectively for excavation, earthing work and leveling work without exchanging the blade 11 for every work of excavation, earthing and leveling, and each work can be performed smoothly and efficiently. Can be done automatically.

  The blade device 10 thus completed includes an integral casting portion 101 obtained by integrally casting the triangular divided end portion 12b, the connecting front surface portion 13 and the end front surface portion 14 of the central front surface portion 12, and the rectangular divided central portion 12a of the central front surface portion 12. However, only by integrating by welding to the left and right end portions of the front plate 106 of the sheet metal portion 105, the front plate 106 of the central front portion 12, the end triangular portion of the central front portion 12, the connecting front portion 13 and the end portions. The front part 14 is assembled at a stretch. At this time, the triangulated end portion 12b, the connecting front surface portion 13 and the end front surface portion 14 are formed by integrating the cylindrical first and second rear surface support portions 103a and 103b with the first and second brackets 25a and 25b. Since it is cast, no other special processing or assembly is required, combined with the use of a welding robot, the assembly of the entire blade is improved, and the assembly time is greatly reduced.

  Moreover, in this integral casting part 101, while making the bending | flexion boundary part of the connection front surface part 13 and the edge part front surface part 14 in which the front-surface board part 102 and the back surface part 103 approach most approach to the minimum necessary, it is rigid. In the casting region of the first bracket 25a that pivotally supports the lift frame 3, particularly in the casting area of the first bracket 25a that supports the lift frame 3, the front plate portion 102 and the second back support portion 103b are cast as a continuous solid structure. Since the space between the front plate portion 102 and the rear portions 103a and 103b in the region is a hollow structure, not only the front-rear width of the blade device 10 can be minimized, but also the weight can be reduced. In particular, the first and second brackets 25a and 25b are cast and integrated with the first and second rear surface support portions 103a and 103b, so that the base end portion is drawn into the rear surface portion 103 and the rearward direction. Since the projecting amount can be reduced, the maximum dimension of the front and rear depth of the blade 11 can be further reduced. On the other hand, the back support member 107 of the sheet metal portion 105 of the central front surface portion 12 also adopts a hollow structure using sheet metal in an area where high rigidity and strength are not required, and an area where high rigidity and strength is required from a cast product. Since the hollow structure having the reinforcing ribs 107d-1 ′, 107d-2 ′, and 107d-3 ′ is employed, the rigidity and strength required for the entire blade are ensured in each region, and the size and weight can be significantly reduced. Can be achieved. As described above, improvement in assemblability and reduction in size and weight are achieved, so that an increase in manufacturing cost can be avoided.

  Furthermore, according to the blade device 10 of the present invention, since the blade front surface shape is the same as that of the above-mentioned Patent Document 1 as described above, even in the present embodiment, the front surface of the connecting front surface portion 13 is excavated and carried. It sometimes has a function of smoothly joining soil moving from the front surfaces of both the central front surface portion 12 and the end front surface portion 14. Further, the end front part 14 has a function of securely holding the soil during excavation / soil so as not to spill out from the side of the blade. The connecting front surface portion 13 and the end front surface portion 14 swell and hold soil along the front surface of each blade, so that the loss of soil volume is reduced and the end front surface portion 14 flows into the central front surface portion 12. The amount of soil deposited on the blade front surface of the central front surface portion 12 can be greatly increased by reducing the resistance of the soil.

  Further, the traction force and the amount of soil per traction force by the blade of the present invention are increased as compared with the conventional blade. The blade of the present invention has reduced excavation resistance compared to conventional blades and reduced soil resistance. Therefore, the horsepower consumed during excavation / landing in the blade of the present invention is lower than the horsepower consumed during excavation / landing in the conventional blade. From the above points, the blade of the present invention can efficiently realize a desired dozer operation with a smaller traction force and excavation force in a shorter time than the conventional operation time as compared with the conventional blade.

  As is clear from the above description, the blade of the blade device according to the present invention can easily determine the shape with the highest excavation efficiency in design, and at the same time, when turning and turning, The soil will not run down from the ground. Further, when the cast body and the sheet metal are combined effectively, the blade structure is simplified, the assembly is easy, the welding workability is improved, and the weight is reduced. Further, as described above, since the blade structure described in Patent Document 1 is provided, the resistance force to the traction force is naturally reduced, and the amount of soil per traction force is reduced as in the blade device described in the same document 6. Of course, it will increase significantly. At the same time, the horsepower consumed during excavation and soiling can be greatly reduced, and the maximum amount of excavation and soiling can be obtained with a minimum amount of energy in a short period of time. The cost can be reduced by improving.

It is the perspective view seen from the front which shows the whole schematic structure of the typical blade apparatus applied to this invention. It is a front view of the said blade apparatus. It is a rear view of the said blade apparatus. It is a side view which shows the whole working machine explaining the raising / lowering operation | movement of the braid | blade of the said blade apparatus. It is a top view which shows the structural example of the principal part of the said working machine. It is explanatory drawing which shows the relationship of the crossing angle of the curved surface and cutting edge in the front surface of a blade part. It is a longitudinal cross-sectional view which shows the back leaning attitude | position when a small-diameter circular arc surface is formed with the same height and the same excavation angle (cutting edge angle). It is a longitudinal cross-sectional view which shows the back leaning attitude | position when a large-diameter circular arc surface is formed with the same height and the same excavation angle (cutting edge angle). It is a projection figure of the blade at the time of excavation and soiling, and the soil before the blade. It is a side view of the blade at the time of excavation and earthing and the earth before the blade. It is explanatory drawing which shows the relationship of the sediment deposited in front of the braid | blade by the normal attitude | position of a braid | blade at the time of excavation and earthing, and a backward inclination attitude | position. It is a correlation diagram which shows the excavation efficiency of the said blade with respect to the blade width | variety of the center front part based on the retreating amount of an intersection, and a back bending angle. It is explanatory drawing which shows the relationship of each braid | blade width | variety of a connection front part and an edge part front part accompanying the fluctuation | variation of a back bending angle and a crossing angle. It is arrow sectional drawing along the XIV-XIV line | wire in FIG. It is arrow sectional drawing along the XV-XV line | wire in FIG. It is arrow sectional drawing along the XVI-XVI line | wire in FIG. It is the perspective view which looked at the left integral casting part in the said blade apparatus from the left side of the back. It is the perspective view which looked at the integral casting part of the right side in the said blade apparatus from the right side of the back surface. It is arrow sectional drawing along the XIX-XIX line | wire of FIG. FIG. 4 is a cross-sectional view taken along line XX-XX in FIG. 3. FIG. 4 is a cross-sectional view taken along the line XXI-XXI in FIG. 3. It is the perspective view which looked at the integral casting part of the right side from diagonally right forward. It is the whole perspective view which looked at the blade device from the slanting back on the back side. It is the perspective view which looked at a part of back support member of a sheet-metal part from the diagonally left front. It is the perspective view which looked at a part of other back surface supporting members of the sheet metal part from the front. It is the perspective view which looked at some other back surface supporting members of the sheet metal part from the front.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bulldozer 2 Crawler type traveling device 3 Lift frame 4 (Hydraulic) Tilt cylinder 5 Engine room 6 (Hydraulic) Lift cylinder 7 Strut arm 10 Blade device 11 Blade 12 Central front surface portion 12a (Rectangle) Divided central portion 12b (Triangle) Divided end Part 13 Connection front part 14 End part front part 15-17 The 1st-3rd cutting blade 18 Upper end sheet metal material 18a Grid 25a-25d 1st-4th bracket 26 Vertical plate rib 101 Integrated casting part 102 Front plate part 103 Back part 103a, 103b First and second back support portions 105 Sheet metal portion 106 Front plate 107 Back support members 107a to 107d First to fourth back support members
107d-1 to 107d-3 Split member
107d-1 'to 107d-3' Reinforcement rib α Cutting edge angle β Drilling angle γ Receding angle δ Back bending angle θ Crossing angle W Full blade width W1 Blade width at the lower end of the front center (= gauge width WG)
Wt Retraction H Blade height R1, R2 Arc radius of curvature

Claims (9)

A blade device mounted on various work machines,
The blade (11) has a central front part (12) and left and right end front parts (14) further connected via a connecting front part (13) bent and connected to the left and right ends. Have
The central front portion (12) has a blade width W1 whose lower end extends in the right and left directions perpendicular to the excavation direction, and further has a first cutting edge (15) at its lower end,
The connecting front surface portion (13) and the end portion front surface portion (14) have second and third cutting edges (16, 17) at their lower ends,
An intersection line of the connecting front surface portion (13) and the end front surface portion (14) and an intersection C of the blade edges (16, 17) of the second and third cutting blades are the first cutting blade (when viewed from above). 15) at the rear of the cutting edge,
The front surfaces of the central front surface portion (12), the connecting front surface portion (13), and the end front surface portion (14) are formed in a circular arc surface having a radius R1 from the upper end to the lower end,
Each of the cutting edges (15 to 17) extends in a tangential direction from the lower end of each front surface portion (12 to 14),
The cutting edge angle α of each cutting edge (15 to 17) is in an excavation posture of 40 ° to 55 °, and the height from the cutting edge of the first cutting edge (15) to the upper end of the central front part is H in side view. The working machine blade device is characterized in that the radius R2 satisfies the following formula (I).
R2 = (0.7 to 1.0) × H (I) A blade device mounted on various work machines,
The blade (11) has a central front part (12) and left and right end front parts (14) further connected via a connecting front part (13) bent and connected to the left and right ends. Have
The central front portion (12) has a blade width W1 whose lower end extends in the right and left directions perpendicular to the excavation direction, and further has a first cutting edge (15) at its lower end,
The connecting front surface portion (13) and the end portion front surface portion (14) have second and third cutting edges (16, 17) at their lower ends,
An intersection line of the connecting front surface portion (13) and the end front surface portion (14) and an intersection C of the blade edges (16, 17) of the second and third cutting blades are the first cutting blade (when viewed from above). 15) at the rear of the cutting edge,
The front surfaces of the central front surface portion (12), the connecting front surface portion (13), and the end front surface portion (14) are formed in a circular arc surface having a radius R1 from the upper end to the lower end,
At least a sheet metal material (18) extending in a substantially tangential direction from the upper end of the central front surface portion (12),
The cutting edge angle α of each cutting edge (15 to 17) is in an excavation posture of 40 ° to 55 °, and the height from the cutting edge of the first cutting edge (15) to the upper end of the sheet metal material (18) in a side view Is a blade device for a working machine, wherein the radius R2 satisfies the following formula (I).
R2 = (0.7 to 1.0) × H (I) The intersection of the blade edges (16, 17) of the second and third cutting blades parallel to the extension line of the first front cutting edge (15) and the extension line of the first front cutting edge (12) is W1. The distance Wt and the rearward bending angle δ are the following, where Wt is the distance from the straight line passing through and the rearward bending angle between the cutting edge of the first cutting edge (15) and the second cutting edge is δ. The blade device according to claim 1 or 2, wherein the blades satisfy the formulas (II) and (III) at the same time.
Wt> 0.65 × (W1 / 10) (II)
14 ° <δ <30 ° ……… (III)   The crossing angle θ intersecting on the extension line (L3, L4) of each cutting edge (15, 17) between the central front part (12) and the end front part (14) is set to 0 ° to 25 °. The blade device according to any one of claims 1 to 3.   At least the front surface of the central front surface portion (12) is formed such that the blade width W1 at the lower end is substantially equal to the blade edge width of the first cutting blade (15) and gradually increases from the lower end toward the upper end. The blade apparatus in any one of 1-4.   The blade device according to any one of claims 1 to 4, wherein a blade width W1 at a lower end of the central front portion (12) is larger than an inner width W0 between the left and right traveling devices.   The blade device according to any one of claims 1 to 4, wherein a blade width W1 at a lower end of the central front surface portion (12) is substantially equal to a gauge width WG which is a distance between centers of left and right traveling devices.   The second cutting edge (16) is inclined slightly to the left and right with respect to the first cutting edge (15), and the third cutting edge (17) is connected to the second cutting edge (16). The blade device according to any one of claims 1 to 4, wherein the blade device is inclined slightly to the left and right.   A construction / civil engineering vehicle comprising the blade device (10) according to claim 1 mounted thereon.

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