Large engineering excavator counterweight structure and forming process thereof

Abstract

The invention relates to the technical field of excavator balance weight structures, in particular to a large engineering excavator balance weight structure and a forming process thereof.The large engineering excavator balance weight structure comprises a balance weight shell, a mounting cavity is formed in the front end of the balance weight shell, and a balance weight assembly is assembled in the mounting cavity; the counterweight assembly comprises a fixed counterweight block fixedly installed in the installation cavity and a movable counterweight block movably arranged in the installation cavity, the fixed counterweight block is provided with a sliding cavity with an upward opening, and the movable counterweight block is assembled in the sliding cavity in a sliding mode; the excavator balance weight structure comprises a movable balance weight block, guide grooves are formed in the two sides of the movable balance weight block, inclined plane transmission wedge blocks are assembled in the two guide grooves, and the two inclined plane transmission wedge blocks achieve left-right horizontal reverse translation through a driving mechanism. The problem that the weight load of the counterweight sliding block and the displacement driving function need to be borne at the same time exists.

Description

Technical Field

[0001] This invention relates to the field of excavator counterweight structure technology, specifically to a large-scale engineering excavator counterweight structure and its molding process. Background Technology

[0002] As a core piece of machinery in engineering construction, the operational stability of large engineering excavators directly affects construction efficiency and safety. The counterweight structure, as a key component of the excavator, is mainly used to balance the weight of the front working device of the excavator, prevent the excavator from tipping over during operation, improve the center of gravity distribution of the excavator, and enhance the overall operating performance of the machine.

[0003] To meet the dynamic adjustment requirements of the center of gravity under different working conditions such as excavation, hoisting, and leveling, existing technologies have developed counterweight products with built-in adjustable center of gravity mechanical structures. Among these, the most widely used is the screw drive adjustment mechanism, which connects a longitudinally arranged ball screw to the nut component of the counterweight slider, driving the slider to slide back and forth along the cavity to adjust the center of gravity position. However, the screw thread pair of this structure must simultaneously bear the weight load of the counterweight slider and the driving displacement function. Under heavy load conditions, it is prone to bending deformation, which leads to a decrease in adjustment accuracy and even complete failure of the adjustment mechanism. In view of the inherent defects of the above-mentioned screw drive adjustment mechanism, there is an urgent need for an excavator counterweight structure with an adjustable center of gravity that can separate heavy load bearing and driving function. Summary of the Invention

[0004] The purpose of this invention is to provide a counterweight structure for large engineering excavators and its molding process, so as to solve the problem that the existing excavator counterweight structure with built-in screw drive for adjusting the center of gravity of the counterweight has to simultaneously bear the weight load of the counterweight slider and the function of driving displacement.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A counterweight structure for a large engineering excavator includes a counterweight housing, with a mounting cavity at the front end of the counterweight housing, and a counterweight assembly assembled inside the mounting cavity.

[0007] The counterweight assembly includes a fixed counterweight block fixedly installed in the mounting cavity and a movable counterweight block movably installed in the mounting cavity. The fixed counterweight block has an upward-facing sliding cavity, and the movable counterweight block is slidably assembled in the sliding cavity.

[0008] The movable counterweight has guide grooves on both sides, and each of the two guide grooves is equipped with an inclined transmission wedge. The two inclined transmission wedges are driven by a drive mechanism to achieve horizontal reverse translation in the left and right directions, thereby driving the movable counterweight to translate in the front and back directions.

[0009] The guide groove is provided with an upper opening, and the top surface of the inclined transmission wedge extends to the outside of the guide groove through the upper opening. A 50mm-100mm allowance is reserved between the bottom wall of the guide groove and the inclined transmission wedge to accommodate the relative vertical movement of the movable counterweight and the inclined transmission wedge.

[0010] Preferably, the driving mechanism includes two first hydraulic telescopic rods, which are installed on the top of the fixed counterweight and are arranged horizontally on both sides of the sliding cavity, with the telescopic ends of the first hydraulic telescopic rods facing each other.

[0011] The telescopic ends of the two first hydraulic telescopic rods are fixedly connected to transmission connecting seats, and the transmission connecting seats are rigidly connected to the top of the inclined transmission wedge block.

[0012] Preferably, the surface of the inclined transmission wedge block that contacts the guide groove wall forms a continuous inclined mating surface, and the cross-section along the horizontal direction is inclined with one side high and one side low. The inclination angle of the inclined mating surface is 15°±2°, and the length of the inclined surface is ≥120mm.

[0013] Preferably, the bottom of the movable counterweight is rotatably connected to a plurality of counterweight rolling supports arranged in a uniform array, and the bottom surface of the counterweight rolling supports is in contact with the bottom of the sliding cavity of the fixed counterweight.

[0014] Preferably, an 8-12mm gap is reserved between the bottom of the sliding cavity of the movable counterweight and the fixed counterweight. This gap is compensated by the installation height of the counterweight rolling support, so that the bottom surface of the rolling support fits against the bottom of the cavity and the bottom surface of the movable counterweight is suspended.

[0015] Preferably, the bottom of the sliding cavity of the fixed counterweight is equipped with a plurality of hydraulically driven counterweight lifting support blocks, the top surface of which is adapted to fit the bottom surface of the movable counterweight to support the movable counterweight.

[0016] A molding process for a counterweight structure of a large engineering excavator, comprising the following specific steps:

[0017] A. The counterweight shell is made of Q355 steel as the base material. After cutting, bending and forming, it is welded and spliced. After welding, the whole is shot blasted to remove rust, and then sprayed with anti-rust primer and topcoat.

[0018] B. Preparation of fixed counterweight: Using HT250 gray cast iron as the base, the inner cavity structure is formed by sand casting. After casting, the casting is placed in an aging furnace and stress-relief annealed at 580℃ for 4 hours. Then, C40 fine stone concrete is poured into the inner cavity, compacted by vibration, and cured for 28 days. The top of the base is then CNC milled to form the first hydraulic telescopic rod mounting seat with internal threads, with a thread depth ≥20mm.

[0019] C. The material of the movable counterweight is the same as that of the fixed counterweight, and it is formed by the same casting process. The guide groove and the mounting groove of the counterweight rolling support are machined on the base. The fitting clearance between the counterweight rolling support and the mounting groove is 0.03mm±0.005mm. Lithium-based grease is evenly coated on the inner wall of the guide groove.

[0020] D. The inclined plane transmission wedge is made of 40Cr alloy structural steel. After forging at 1120℃, it is subjected to oil quenching at 850℃ and tempering at 520℃. The treated material is then processed into an inclined plane structure with an inclination angle of 15°±2° and an inclined plane length of ≥120mm. The transmission connection seat and the counterweight lifting support block are made of the same material and heat treatment process.

[0021] E. Secure the fixed counterweight block to the inside of the counterweight housing with bolts, embed the movable counterweight block into the counterweight housing, and then assemble the inclined plane transmission wedge block so that the inclined plane of the inclined plane transmission wedge block is completely in contact with the inclined plane of the guide groove. Install the first hydraulic telescopic rod on the mounting base and rigidly connect it to the inclined plane transmission wedge block through the transmission connecting base.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. The separation of load-bearing and driving functions is achieved, which greatly improves the reliability of the mechanism. There is no rigid constraint between the inclined plane transmission wedge and the guide groove. The heavy load of the movable counterweight is borne by the sliding cavity and rolling support of the fixed counterweight. The inclined plane transmission wedge only undertakes the function of driving displacement, which completely avoids the superposition of load and drive in traditional screw transmission and extends the service life of the center of gravity adjustment mechanism.

[0024] 2. The two first hydraulic telescopic rods are symmetrically arranged and driven synchronously, providing strong thrust and stable output. They can meet the adjustment requirements of ton-class movable counterweights. The inclined plane transmission structure achieves smooth movement of the movable counterweight through force decomposition, avoiding the impact of rigid drive and adapting to the center of gravity adjustment requirements of different working conditions such as excavation and hoisting. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is a top view of the counterweight housing of the present invention cut out;

[0027] Figure 3 This is a cross-sectional schematic diagram of the movable counterweight block of the present invention.

[0028] In the figure: 1. Counterweight housing; 2. Fixed counterweight block; 3. Movable counterweight block; 4. Guide groove; 5. Inclined transmission wedge block; 6. Transmission connecting seat; 7. First hydraulic telescopic rod; 8. Counterweight rolling support; 9. Counterweight lifting support block. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figures 1 to 3 The present invention provides a technical solution: a counterweight structure for a large engineering excavator, including a counterweight housing 1, an installation cavity at the front end of the counterweight housing 1, a counterweight assembly assembled in the installation cavity, the counterweight assembly including a fixed counterweight block 2 fixedly installed in the installation cavity, and a movable counterweight block 3 movably disposed in the installation cavity, the fixed counterweight block 2 having an upward-facing sliding cavity, the movable counterweight block 3 being slidably assembled in the sliding cavity, and the sliding cavity limiting the sliding trajectory of the movable counterweight block 3, so that the movable counterweight block 3 can only move in the forward and backward direction of the horizontal coordinate system.

[0031] Two first hydraulic telescopic rods 7 are installed on the top of the fixed counterweight 2. The two first hydraulic telescopic rods 7 are located on both sides of the sliding cavity and are arranged horizontally from left to right with their telescopic ends facing each other. The telescopic ends of the two first hydraulic telescopic rods 7 are fixedly connected to a transmission connecting seat 6. The bottom ends of the two transmission connecting seats 6 are fixedly connected to an inclined transmission wedge 5. The two inclined transmission wedges 5 are arranged symmetrically.

[0032] The movable counterweight 3 has guide grooves 4 on both sides that are adapted to the inclined plane transmission wedge 5. The guide groove 4 has an upper opening, and the top surface of the inclined plane transmission wedge 5 extends to the outside of the guide groove 4 through the upper opening. The bottom wall of the guide groove 4 has a reserved amount of movement, which allows the movable counterweight 3 and the inclined plane transmission wedge 5 to move up and down relative to each other.

[0033] Through the above structural design, there is no rigid constraint between the inclined plane transmission wedge 5 and the guide groove 4, which realizes the separation of the heavy load bearing function of the movable counterweight 3 and the driving function of the inclined plane transmission wedge 5. When the two inclined plane transmission wedges 5 move horizontally towards each other, they can drive the movable counterweight 3 to move backward to adjust the counterweight position. When the two inclined plane transmission wedges 5 move horizontally away from each other, they can drive the movable counterweight 3 to move forward to adjust the counterweight position.

[0034] Please refer to Figure 2 The structure of the left inclined transmission wedge 5 is as follows. The right inclined transmission wedge 5 is symmetrically arranged with the left side, and the two have the same structure. The inclined transmission wedge 5 is a block-shaped transmission component that is adapted to the guide groove 4. The surface of the wedge 5 that contacts the wall of the guide groove 4 forms a continuous inclined mating surface. In the top view, the inclined mating surface has an inclined shape that is higher on the left and lower on the right.

[0035] The groove profile of the guide groove 4 is complementary to the planar shape of the inclined transmission wedge 5. The groove wall near the inclined transmission wedge 5 forms an inclined groove wall, and the inclined groove wall has the same inclination angle as the inclined mating surface. When the inclined transmission wedge 5 is embedded in the guide groove 4, the inclined surfaces of the two are in close contact, forming an inclined transmission mating structure.

[0036] When the first hydraulic telescopic rod 7 is activated, the drive transmission connecting seat 6 drives the left inclined transmission wedge block 5 to move horizontally to the right. Its inclined mating surface will apply inclined extrusion force to the inclined groove wall of the guide groove 4. This extrusion force is decomposed into a transmission component force in the vertical upward direction (top view), which in turn drives the movable counterweight block 3 to move vertically upward (top view). Conversely, when the inclined transmission wedge block 5 moves horizontally to the left, the extrusion force applied by the inclined mating surface to the inclined groove wall will be decomposed into a transmission component force in the vertical downward direction (top view), which drives the movable counterweight block 3 to move vertically downward (top view).

[0037] A gap is reserved between the movable counterweight 3 and the bottom of the sliding cavity of the fixed counterweight 2. The bottom of the movable counterweight 3 is rotatably connected to multiple evenly arranged counterweight rolling support members 8. The bottom surface of the counterweight rolling support member 8 is in contact with the bottom of the sliding cavity of the fixed counterweight 2, and the arrangement of the counterweight rolling support member 8 matches the forward and backward movement direction of the movable counterweight 3. Specifically, if the counterweight rolling support member 8 adopts a roller structure, it is arranged in the horizontal direction of left and right, which can effectively reduce the frictional resistance between the movable counterweight 3 and the bottom of the sliding cavity when it moves forward and backward.

[0038] The bottom of the sliding cavity of the fixed counterweight 2 is equipped with multiple counterweight lifting support blocks 9 that can be raised and lowered. Each counterweight lifting support block 9 is driven by an independent second hydraulic telescopic rod to move up and down. When the movable counterweight 3 moves to the designated position, the counterweight lifting support block 9 is lifted upward under the drive of the second hydraulic telescopic rod and pressed against the bottom of the movable counterweight 3 to form a rigid auxiliary support and improve the placement stability of the movable counterweight 3.

[0039] Specifically, this solution involves: determining the target movement direction and final positioning of the movable counterweight 3 based on the excavator's operating scenario (such as heavy-duty excavation or slewing operation), and marking the corresponding support points at the bottom of the sliding cavity.

[0040] Rearward adjustment (increasing the tail counterweight torque): Activate the control system of the first hydraulic telescopic rod 7 and set the telescopic rods on both sides to extend in opposite directions; the first hydraulic telescopic rods 7 on both sides extend synchronously, driving the transmission connecting seat 6 to move the inclined transmission wedge 5 in opposite directions in the left and right horizontal directions; the inclined mating surface of the inclined transmission wedge 5 fits and presses against the inclined groove wall of the guide groove 4, generating a transmission component force, which drives the movable counterweight 3 to move backward in the front-back direction of the sliding cavity; during the movement, the counterweight rolling support 8 (roller) rolls in the left and right directions, reducing the frictional resistance between the movable counterweight 3 and the bottom of the cavity, and the sliding cavity limits the movable counterweight 3 to ensure that it only moves in the front-back direction without any left or right deviation; after reaching the target position, stop the action of the first hydraulic telescopic rod 7 and maintain the current position of the wedge.

[0041] Forward adjustment (reducing the tail counterweight torque): Activate the control system of the first hydraulic telescopic rod 7 and set the telescopic rods on both sides to extend and retract in opposite directions; the first hydraulic telescopic rods 7 on both sides retract synchronously, driving the transmission connecting seat 6 to drive the inclined transmission wedge 5 to move in opposite directions in the left and right horizontal directions; the inclined mating surface of the inclined transmission wedge 5 is pressed against the inclined groove wall of the guide groove 4 in the opposite direction, generating a transmission component force, which drives the movable counterweight 3 to move forward in the front and back direction of the sliding cavity.

[0042] After confirming that the movable counterweight 3 is stationary and in a precise position, the second hydraulic telescopic rod control system is activated; the independent second hydraulic telescopic rods corresponding to each counterweight lifting support block 9 are controlled to extend synchronously, driving the counterweight lifting support blocks to move upward; until the top surfaces of all counterweight lifting support blocks are evenly pressed against the bottom of the movable counterweight 3, forming auxiliary support and improving placement stability; the stress state of each counterweight lifting support block is checked to ensure that there is no suspension or uneven loading, and the hydraulic circuit maintains pressure lock.

[0043] A molding process for a counterweight structure of a large engineering excavator, comprising the following specific steps:

[0044] A. The counterweight shell 1 is made of Q355 steel as the base material. After cutting, bending and forming, it is welded and spliced. After welding, the whole is shot blasted to remove rust, and then sprayed with anti-rust primer and topcoat.

[0045] B. Preparation of fixed counterweight 2: Using HT250 gray cast iron as the base, the inner cavity structure is formed by sand casting. After casting, the casting is placed in an aging furnace and stress-relief annealed at 580℃ for 4 hours. Then, C40 fine stone concrete is poured into the inner cavity, compacted by vibration, and cured for 28 days. The top of the base is then CNC milled to form the mounting seat of the first hydraulic telescopic rod 7 with internal threads. The thread depth is ≥20mm (to meet the installation strength and pull-out force requirements of the first hydraulic telescopic rod).

[0046] C. The material of the movable counterweight 3 is the same as that of the fixed counterweight 2. It is formed by the same casting process. The guide groove 4 and the mounting groove of the counterweight rolling support 8 are machined on the base. The fit clearance between the counterweight rolling support 8 and the mounting groove is 0.03mm±0.005mm. Lithium-based grease is evenly coated on the inner wall of the guide groove 4 to reduce transmission friction.

[0047] D. The inclined transmission wedge 5 is made of 40Cr alloy structural steel. After forging at 1120℃, it is subjected to oil quenching at 850℃ and tempering at 520℃. The treated material is then processed into an inclined structure with an inclination angle of 15°±2° and an inclined length of ≥120mm. The transmission connecting seat 6 and the counterweight lifting support block 9 are made of the same material and heat treatment process.

[0048] E. Secure the fixed counterweight 2 to the inside of the counterweight housing 1 with bolts, embed the movable counterweight 3 into the counterweight housing 1, and then assemble the inclined plane transmission wedge 5 so that the inclined plane of the inclined plane transmission wedge 5 is completely in contact with the inclined plane of the guide groove 4. Install the first hydraulic telescopic rod 7 on the mounting base and rigidly connect it to the inclined plane transmission wedge 5 through the transmission connecting seat 6.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A counterweight structure for a large engineering excavator, comprising a counterweight housing (1), characterized in that, The front end of the counterweight housing (1) is provided with an installation cavity, and a counterweight assembly is assembled in the installation cavity; The counterweight assembly includes a fixed counterweight block (2) fixedly installed in the mounting cavity and a movable counterweight block (3) movably installed in the mounting cavity. The fixed counterweight block (2) has an upward-facing sliding cavity, and the movable counterweight block (3) is slidably assembled in the sliding cavity. The movable counterweight (3) has guide grooves (4) on both sides. Each of the two guide grooves (4) is equipped with an inclined transmission wedge (5). The two inclined transmission wedges (5) are driven by a drive mechanism to achieve horizontal reverse translation in the left and right directions, thereby driving the movable counterweight (3) to translate in the front and back directions. The guide groove (4) is provided with an upper opening. The top surface of the inclined transmission wedge (5) extends to the outside of the guide groove (4) through the upper opening. A 50mm-100mm movement allowance is reserved between the bottom wall of the guide groove (4) and the inclined transmission wedge (5) to accommodate the relative up-down movement of the movable counterweight (3) and the inclined transmission wedge (5).

2. The counterweight structure for a large engineering excavator according to claim 1, characterized in that, The driving mechanism includes two first hydraulic telescopic rods (7). The two first hydraulic telescopic rods (7) are installed on the top of the fixed counterweight (2) and are arranged horizontally on both sides of the sliding cavity. The telescopic ends of the first hydraulic telescopic rods (7) are arranged opposite each other. The telescopic ends of the two first hydraulic telescopic rods (7) are fixedly connected to a transmission connecting seat (6), and the transmission connecting seat (6) is rigidly connected to the top end of the inclined plane transmission wedge (5).

3. The counterweight structure for a large engineering excavator according to claim 1, characterized in that, The inclined transmission wedge (5) and the guide groove (4) form a continuous inclined mating surface. The cross-section along the horizontal direction is inclined with one side high and one side low. The inclination angle of the inclined mating surface is 15°±2° and the length of the inclined surface is ≥120mm.

4. The counterweight structure for a large engineering excavator according to claim 1, characterized in that, The bottom of the movable counterweight (3) is rotatably connected to a plurality of uniformly arranged counterweight rolling support members (8), and the bottom surface of the counterweight rolling support member (8) is in contact with the bottom of the sliding cavity of the fixed counterweight (2).

5. The counterweight structure for a large engineering excavator according to claim 4, characterized in that, An 8-12mm gap is reserved between the bottom of the sliding cavity of the movable counterweight (3) and the fixed counterweight (2).

6. The counterweight structure for a large engineering excavator according to claim 1, characterized in that, The bottom of the sliding cavity of the fixed counterweight block (2) is equipped with multiple hydraulically driven counterweight lifting support blocks (9). The top surface of the counterweight lifting support block (9) is adapted to fit the bottom surface of the movable counterweight block (3) to support the movable counterweight block (3).

7. A molding process for the counterweight structure of a large engineering excavator based on claim 1, characterized in that, The specific steps are as follows: A. The counterweight shell (1) is made of Q355 steel as the base material. After cutting and bending, it is welded and spliced. After welding, the whole is shot blasted to remove rust, and then sprayed with anti-rust primer and topcoat. B. Preparation of fixed counterweight (2): HT250 gray cast iron is used as the base. The inner cavity structure is formed by sand casting. After casting, the casting is placed in an aging furnace and held at 580℃ for 4 hours for stress relief annealing. Then, C40 fine stone concrete is poured into the inner cavity and compacted by vibration. After curing for 28 days, the top of the base is CNC milled to form the first hydraulic telescopic rod (7) mounting seat with internal thread, and the thread depth is ≥20mm. C. The material of the movable counterweight (3) is the same as that of the fixed counterweight (2), and it is formed by the same casting process. The guide groove (4) and the mounting groove of the counterweight rolling support (8) are machined on the base. The clearance between the counterweight rolling support (8) and the mounting groove is 0.03mm±0.005mm. Lithium-based grease is uniformly coated on the inner wall of the guide groove (4). D. The inclined transmission wedge (5) is made of 40Cr alloy structural steel. After forging at 1120℃, it is subjected to oil quenching at 850℃ and tempering at 520℃. The treated material is processed into an inclined structure with an inclination angle of 15°±2° and an inclined length of ≥120mm. The transmission connection seat (6) and the counterweight lifting support block (9) are made of the same material and heat treatment process. E. Secure the fixed counterweight (2) to the inside of the counterweight housing (1) with bolts, embed the movable counterweight (3) into the counterweight housing (1), and then assemble the inclined surface transmission wedge (5) so that the inclined surface of the inclined surface transmission wedge (5) is fully in contact with the inclined surface of the guide groove (4). Install the first hydraulic telescopic rod (7) on the mounting base and rigidly connect it to the inclined surface transmission wedge (5) through the transmission connecting seat (6).

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