Application and Practice of the Concept of "Equivalent Life Design" in Jaw Plate Structure Design

The concept of "equal lifespan design" is an advanced engineering idea to improve the technical and economic efficiency of jaw plates in jaw crushers. The core goal is to optimize the geometric structure and contour of the jaw plate, so that the wear rate in each area becomes consistent during operation, thereby maximizing material utilization, reducing replacement and downtime caused by local premature failure, and lowering overall operating costs. This article will explore how to approach the goal of "synchronous and uniform wear" through the collaborative design of tooth profile, thickness curve, and reinforcement rib layout.

1、 The engineering foundation of "equal life design": understanding the uneven wear of jaw plates

The wear of traditional jaw plates (especially fixed jaw plates) usually exhibits significant unevenness, with the lower part wearing much faster than the upper part. The fundamental reason is that:

Uneven distribution of crushing force: In the crushing chamber, the closer the material is to the discharge port, the greater the pressure on the material from the upper layer, and the greater the crushing force.

Material sliding path: The material moves downward under the action of gravity, forming sliding friction on the surface of the fixed jaw plate, and the accumulation of travel leads to increased wear on the lower part.

Difference in impact angle: The engagement angle and impact mode between different areas of the moving jaw plate and the material are different.

The 'equal lifespan design' is aimed at actively combating this inherent non-uniformity.

2、 Implementation Path: Collaborative Optimization of Key Structural Elements

1. Tooth profile optimization: from "single tooth profile" to "adaptive tooth profile"

The tooth shape design directly affects the meshing efficiency, crushing force distribution, and wear mode.

Concept: Change the tooth profile design that is exactly the same along the height direction of the jaw plate.

Practical methods:

Upper part (less worn area): A relatively sharp and higher tooth profile can be used. This helps to initially bite large pieces of material, improve crushing efficiency, and utilize the potential for wear in this area.

Middle (transition zone): Adopting a tooth profile with moderate height and angle to balance bite and wear resistance.

Lower part (severely worn area): Adopt a more blunt, thicker, and larger rounded tooth profile, even using bimodal or trapezoidal teeth. This can increase the cross-sectional area and anti-wear volume of the teeth, disperse stress, and slow down the wear rate. Meanwhile, optimizing the inclination angle of the teeth can improve material flow and reduce unnecessary sliding friction.

2. Thickness Curve Design: From "Equal Thickness" to "Variable Thickness"

The thickness curve of the back of the jaw plate is the determining factor for its load-bearing capacity and bending stiffness.

Concept: Based on the distribution law of crushing force along the cavity height, design a nonlinear thickness curve that matches it, so that the stress levels at all locations approach each other.

Practical methods:

Traditional thick plates: In the lower high stress zone, insufficient section modulus can easily lead to excessive bending stress, accelerated wear and fatigue.

Variable thickness plate (key): The thickness of the jaw plate should gradually and non linearly increase from top to bottom. Usually, it is designed to be the thickest near the discharge port (lower part), forming sufficient cross-sectional modulus to resist huge crushing forces. Through computer-aided engineering (CAE) stress analysis, this curve can be optimized with the goal of ensuring that the maximum principal stress value of the entire jaw plate remains within a relatively uniform and safe range under rated load.

3. Strengthening the layout of reinforcement: from "uniform arrangement" to "mechanically guided arrangement"

Strengthening ribs are used to increase the overall stiffness of the jaw plate and prevent deformation, but their layout must follow mechanical principles.

Concept: Place reinforcement bars on critical paths that require increased bending or torsional stiffness, rather than simply arranging them symmetrically.

Practical methods:

Horizontal reinforcement (main load-bearing reinforcement): It should be concentrated in the high stress area of the lower part of the jaw plate, with a spacing smaller than the upper part. These ribs can effectively resist the lateral bending deformation of the jaw plate.

Longitudinal and side ribs: Longitudinal ribs are arranged on both sides of the jaw plate and in the center of the back, which helps to maintain overall stability and can more evenly transmit stress to the support surface of the jaw bed.

The height and thickness of the reinforcement bars: The cross-sectional size of the reinforcing bars in high stress areas can be appropriately increased. The root of the tendon needs to be designed with a sufficiently large rounded transition to avoid stress concentration leading to cracking.

The following table summarizes the comparison of design ideas for the three elements mentioned above:

Design elements, common characteristics of traditional design, optimization direction of "equal life design", and main objectives

The tooth profile of the entire plate is uniform, mostly consisting of symmetrical pointed teeth. Adaptively changing along height: pointed at the top, moderately adapted, and blunt at the bottom. Balance bite efficiency and local wear resistance, adjust wear distribution.

Thickness curve with equal thickness or simple linear thickening. Nonlinear gradient thickening, optimized based on CAE analysis, significantly enhanced in the lower part. Make the working stress field more uniform and avoid local overload.

Strengthen the layout rules and arrange them evenly. Strengthen high stress areas based on non-uniform layout of principal stress traces. Accurately enhance overall stiffness and suppress harmful deformation.

3、 Design validation and limitations

Verification method:

Finite element analysis: is a core validation tool. By simulating the crushing process, the stress distribution, deformation cloud map, and fatigue life prediction of the jaw plate before and after optimization can be visually displayed, verifying whether the design is approaching the goals of "equal stress" and "equal life".

Actual working condition verification: Small batch trial production and industrial operation, regular measurement of wear in different height areas, and drawing of wear curves are the final inspection standards.

Cognition of the limitations of ideas:

'Equal lifespan' is an ideal approach goal, but in practice, it is difficult to achieve completely synchronous wear due to fluctuations in material properties, feeding conditions, and other factors.

This design must be combined with the correct material selection. If an optimized structure is paired with inappropriate materials, its advantages cannot be fully realized.

It highly relies on precise installation and adequate back support. If the installation surface has poor contact, any optimized design will fail.

Conclusion

The application of the concept of "equal lifespan design" to jaw plate structures marks a shift from passive replacement to active design. By synergistically optimizing the tooth profile, thickness curve, and reinforcement rib layout, the mechanical state inside the jaw plate can be significantly improved, guiding its wear mode from "local rapid failure" to "overall uniform consumption".

The value of this design practice lies in its ability to effectively improve the metal utilization rate of a single jaw plate, extend the average replacement cycle, and provide structural engineering support for reducing the cost of crushing one ton of ore and improving production continuity. However, it is not an independent solution, and its effectiveness must be based on scientific material matching, rigorous manufacturing processes, and standardized installation and maintenance.