Inserted hob structure adopting tapered roller bearing
By adopting tapered roller bearings and optimizing the preload structure, the problems of uneven load distribution and insufficient stiffness of existing cutters in hard rock crushing have been solved, achieving high-efficiency load bearing, stable preload, and long service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-03
- Publication Date
- 2026-04-03
AI Technical Summary
Existing roller cutter structures suffer from uneven load distribution, insufficient stiffness, short lifespan, and frequent maintenance when breaking hard rock. In particular, the combination of thrust bearings and cylindrical bearings is prone to uneven load distribution, vibration, and difficulties in preload adjustment under combined loads.
The bearing uses tapered roller bearings and achieves an interference fit between the outer ring and the housing through a cold assembly process. Combined with an adjustable spacer ring and three-stage preload adjustment, the preload structure is optimized, and a sealing component is set at the bearing end to ensure that the bearing operates in a clean environment and reduce the entry of impurities.
It achieves uniform load distribution, reduces vibration and noise, extends bearing life, improves the equipment's high-efficiency load-bearing capacity and stability, and enhances environmental adaptability.
Smart Images
Figure CN224079131U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of engineering machinery and equipment technology, and in particular to a toothed hob structure using tapered roller bearings. Background Technology
[0002] As a core component in the field of engineering machinery equipment, the importance of toothed hobs is self-evident. Especially in applications such as hard rock breaking and heavy cutting, toothed hobs are widely used in infrastructure construction, mineral resource development and tunnel construction. They are indispensable rock breaking tools, and their efficient and stable performance plays a vital role in improving construction efficiency and reducing operating costs.
[0003] Currently available hobs employ a combination of thrust bearings and cylindrical bearings or a combination of ball bearings and roller bearings, which have the following drawbacks when performing heavy cutting in hard rock crushing;
[0004] 1. Thrust bearing plus cylindrical bearing combination
[0005] Thrust bearings only bear axial loads, while cylindrical bearings only bear radial loads. Under combined loads, the force needs to be precisely distributed. In actual operation, uneven load distribution is prone to occur, leading to overload failure of the thrust bearing (such as raceway crushing).
[0006] 2. Thrust bearings have high axial stiffness but low radial stiffness, while roller bearings have the opposite. When the two are combined, the system stiffness changes nonlinearly, which can easily cause vibration during load cutting.
[0007] 3. Preload adjustment is difficult and requires separate adjustment of the thrust bearing clearance and roller bearing clearance, with the adjustment parameters being coupled together.
[0008] 4. Under combined load (axial + radial) conditions, the load distribution of the ball-roller combination structure is prone to problems due to the high precision of machining and assembly: overload of steel balls, stress concentration caused by contact between steel balls and raceway edges, and increased edge stress caused by roller tilting due to axial component force. Due to structural reasons, pre-tightening cannot eliminate clearance, and cross-flow exists in both axial and radial directions.
[0009] Therefore, those skilled in the art have provided a toothed hob structure employing tapered roller bearings to solve the problems mentioned in the background art. Utility Model Content
[0010] The purpose of this utility model is to address the shortcomings of existing technologies and provide a toothed hob structure using tapered roller bearings. Through the innovative application of tapered roller bearings, optimization of preload structure, and sealing design, it systematically solves the problems of uneven load distribution, insufficient rigidity, short life, and frequent maintenance of existing hobs in hard rock crushing, achieving a technological breakthrough of "high-efficiency load bearing, stable preload, long life, and strong environmental adaptability".
[0011] To achieve the above objectives, this utility model provides a toothed hob structure using tapered roller bearings, comprising a central shaft, a housing, and a locking cover. The housing is fitted onto the outer wall of the central shaft, and a left cover is tightly fitted to the inner wall of the front end of the housing. Tapered roller bearing assemblies are fixedly connected to both the front and rear ends of the outer wall of the central shaft. The outer walls of the tapered roller bearing assemblies are tightly fitted to the inner wall of the housing, and the outer walls of the front and rear ends of the tapered roller bearing assemblies are tightly fitted to the outer walls of the adjacent sides of the left cover and the locking cover, respectively. An adjustable spacer ring is provided in the middle of the tapered roller bearing assemblies.
[0012] The above technical solution employs a cold-fitting process when assembling the outer ring of the tapered roller bearing, then installs it into the bearing housing. This cold-fitting process achieves an interference fit between the outer ring and the housing, ensuring a tight, gap-free fit and enhancing the overall structural rigidity and stability. Furthermore, the preload is adjustable in three levels, allowing for performance optimization by selecting different levels of preload according to actual application requirements. Applying preload eliminates internal bearing clearance, resulting in a more even load distribution on the bearing assembly during operation, reducing vibration and noise, and extending its lifespan.
[0013] Furthermore, the inner wall of the adjustable spacer ring is tightly fitted to the outer wall of the central shaft, the inner wall of the locking cover is tightly fitted to the outer wall of the rear end of the central shaft, and the outer wall of the locking cover is tightly fitted to the inner wall of the rear end of the outer shell.
[0014] With the above technical solution, the spacer is located between the inner rings of the two tapered roller bearing assemblies. By adjusting its thickness or position, a preload is applied to the bearing, with the preload range being -0.06 to 0 mm.
[0015] Furthermore, the left cover and the locking cover are respectively tightly fitted with sealing components at the adjacent ends of the tapered roller bearing assemblies at both ends;
[0016] The above technical solution forms a physical barrier by setting sealing components on the adjacent end faces of the left cover, locking cover and bearing assembly, preventing external impurities from entering the interior through the bearing end gap, ensuring that the bearing operates in a clean environment, maintaining stable lubrication, and the tightly fitting sealing structure can effectively prevent the internal lubrication medium of the bearing from leaking out, ensuring the long-term effectiveness of the lubrication system.
[0017] Furthermore, the outer wall of the outer shell is fixedly connected with multiple blades;
[0018] Through the above technical solution, the cutting teeth are the actuators that directly contact and crush rocks. They are usually made of cemented carbide or high-strength steel. They cut into hard rocks through sharp edges or tooth-shaped structures to achieve cutting or crushing.
[0019] Furthermore, the contact angle of the tapered roller bearing assembly is 24°, and the tapered roller bearing assembly undergoes a special surface hardening treatment;
[0020] Through the above technical solution, hard rock cutting needs to withstand both axial propulsion force and radial cutting force at the same time. The 24° contact angle can make the stress distribution of the bearing more uniform under the two types of loads, reducing the risk of local overload. When hard rock is broken, the bearing surface is frequently subjected to impact and friction. Hardening treatment can reduce the surface wear rate and extend the bearing life.
[0021] This utility model has the following beneficial effects:
[0022] This utility model proposes a toothed hob structure using tapered roller bearings. Through the innovative application of tapered roller bearings, optimization of preload structure, and sealing design, it systematically solves the problems of uneven load distribution, insufficient rigidity, short life, and frequent maintenance of existing hobs in hard rock crushing, achieving a technological breakthrough of "high-efficiency load bearing, stable preload, long life, and strong environmental adaptability". Attached Figure Description
[0023] Figure 1 This is a bottom view of a toothed hob structure using tapered roller bearings proposed in this utility model;
[0024] Figure 2 This is a side view of a toothed hob structure using tapered roller bearings proposed in this utility model;
[0025] Figure 3 This is a top view of a toothed hob structure using tapered roller bearings proposed in this utility model;
[0026] Figure 4 This is a cross-sectional side view of a toothed hob structure using tapered roller bearings proposed in this utility model.
[0027] Explanation of reference numerals in the attached figures:
[0028] 1. Central shaft; 2. Left cover; 3. Tapered roller bearing assembly; 4. Spacer ring; 5. Sealing assembly; 6. Locking cover; 7. Housing; 8. Cutting teeth. Detailed Implementation
[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of specific embodiments. Obviously, the described specific embodiments are only a part of the specific embodiments of the present invention, and not all of them. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0030] Reference Figure 2 , Figure 3 and Figure 4 This utility model provides a specific embodiment: a toothed hob structure using tapered roller bearings, comprising a central shaft 1, a housing 7, and a locking cover 6. The housing 7 is sleeved on the outer wall of the central shaft 1. A left cover 2 is tightly fitted to the inner wall of the front end of the housing 7. Tapered roller bearing assemblies 3 are fixedly connected to both the front and rear ends of the outer wall of the central shaft 1. The outer walls of the tapered roller bearing assemblies 3 are tightly fitted to the inner walls of the housing 7. The outer walls of the front and rear ends of the tapered roller bearing assemblies 3 are respectively tightly fitted to the outer walls of the left cover 2 and the locking cover 6 on their adjacent sides. An adjustable spacer ring is provided in the middle of the tapered roller bearing assemblies 3. 4. When assembling the outer ring of the tapered roller bearing, a cold-fitting process is adopted, and then it is installed into the bearing housing 7. The cold-fitting process achieves an interference fit between the outer ring and the housing 7. The outer ring size is slightly larger than the mounting hole, ensuring that there is no gap between the bearing outer ring and the housing 7 and that they are tightly fixed, thereby improving the rigidity and stability of the overall structure. In addition, the preload is adjusted in three levels. Different levels of preload are selected according to the actual application requirements to optimize performance. By applying the preload, the internal clearance of the bearing is eliminated, so that the bearing assembly bears a more uniform load during operation, reducing vibration and noise and extending service life.
[0031] Reference Figure 1 , Figure 2 and Figure 4 The inner wall of the adjustable spacer ring 4 is tightly fitted to the outer wall of the middle part of the central shaft 1. The inner wall of the locking cover 6 is tightly fitted to the outer wall of the rear end of the central shaft 1. The outer wall of the locking cover 6 is tightly fitted to the inner wall of the rear end of the housing 7. The spacer ring 4 is located between the inner rings of the two tapered roller bearing assemblies 3. By adjusting its thickness or position, a preload is applied to the bearing. The preload range is -0.06-0mm. The left cover 2 and the locking cover 6 are respectively tightly fitted with sealing components 5 at the adjacent ends of the tapered roller bearing assemblies 3. By setting the sealing components 5 on the adjacent end faces of the left cover 2, the locking cover 6 and the bearing assembly, a physical barrier is formed to prevent external impurities from entering the interior through the bearing end gap, ensuring that the bearing operates in a clean environment, maintaining a stable lubrication state, and the tightly fitted sealing structure can effectively keep the internal lubrication medium of the bearing from leaking out, ensuring the long-term effectiveness of the lubrication system.
[0032] Reference Figure 2 and Figure 4Multiple cutting teeth 8 are fixedly connected to the outer wall of the outer shell 7. The cutting teeth 8 are the actuators that directly contact and crush the rock. They are usually made of cemented carbide or high-strength steel. They cut into the hard rock through sharp edges or toothed structures to achieve cutting or crushing. The contact angle of the tapered roller bearing assembly 3 is 24°. The tapered roller bearing assembly 3 adopts a special surface hardening treatment. When cutting hard rock, it needs to withstand both axial thrust and radial cutting force at the same time. The 24° contact angle can make the stress distribution of the bearing more uniform under the two types of loads and reduce the risk of local overload. When crushing hard rock, the bearing surface is frequently subjected to impact and friction. The hardening treatment can reduce the surface wear rate and extend the bearing life.
[0033] Working Principle: First, the central shaft 1, as the core component, has tapered roller bearing assemblies 3 fixedly connected to its front and rear ends, providing support and rotation for the equipment. The outer shell 7 is fitted onto the outer wall of the central shaft 1, with the left cover 2 tightly fitted to the inner wall of the front end and the locking cover 6 tightly fitted to the inner wall of the rear end, forming the main structure of the equipment. During assembly, the outer ring of the tapered roller bearing is installed into the bearing housing of the outer shell 7 using a cold-fitting process, achieving an interference fit between the outer ring and the outer shell 7, ensuring no gaps and tight fixation, thus improving the rigidity and stability of the overall structure. The adjustable spacer ring 4 is located between the inner rings of the two tapered roller bearing assemblies 3, with its inner wall tightly fitted to the outer wall of the middle part of the central shaft 1. By adjusting the thickness or position of the spacer ring 4, a preload is applied to the bearing. The preload range is -0.06-0mm. Applying the preload eliminates internal clearance in the bearing, allowing the bearing assembly to bear the load more evenly during operation, reducing vibration and noise, and extending its service life. The preload is adjustable in three levels, depending on the actual application requirements. To optimize performance, different levels of preload are selected. The left cover 2 and locking cover 6 are tightly fitted with sealing components 5 at their adjacent ends to the tapered roller bearing assemblies 3. These sealing components 5 form a physical barrier, preventing external impurities from entering the bearing through the end gaps, ensuring the bearing operates in a clean environment and maintaining stable lubrication. Simultaneously, the tightly fitted sealing structure effectively prevents leakage of the internal lubricating medium, ensuring long-term effectiveness of the lubrication system. Multiple cutting teeth 8 are fixedly connected to the outer wall of the outer casing 7. These cutting teeth 8 are the actuating components that directly contact and crush rocks. They are typically made of hard alloy or high-strength steel, cutting into hard rock with sharp edges or toothed structures to achieve cutting or crushing. The tapered roller bearing assembly 3 has a contact angle of 24° and undergoes special surface hardening treatment. The 24° contact angle allows for more uniform stress distribution when the bearing is subjected to axial thrust and radial cutting forces, reducing the risk of localized overload. The hardening treatment also reduces the bearing surface wear rate and extends bearing life.
[0034] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing specific embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A structure of a profile inserted hobbing cutter using a tapered roller bearing, comprising a center shaft (1), an outer shell (7) and a locking cover (6), characterized in that: The shell (7) is sleeved on the outer wall of the central shaft (1), the inner wall of the front end of the shell (7) is tightly attached with the left cover (2), the front and rear ends of the outer wall of the central shaft (1) are fixedly connected with the tapered roller bearing groups (3), the outer walls of the tapered roller bearing groups (3) are tightly attached with the inner walls of the shell (7), the outer walls of the front and rear ends of the tapered roller bearing groups (3) are respectively tightly attached with the outer walls of the adjacent two sides of the left cover (2) and the locking cover (6), and the middle part of the tapered roller bearing group (3) is provided with an adjustable spacer ring (4).
2. The profile cutting hob structure employing a tapered roller bearing according to claim 1, characterized in that: The inner wall of the adjustable spacer ring (4) is tightly attached with the outer wall of the middle part of the central shaft (1), the inner wall of the locking cover (6) is tightly attached with the outer wall of the rear end of the central shaft (1), and the outer wall of the locking cover (6) is tightly attached with the inner wall of the rear end of the shell (7).
3. The profiled insert cutter having a conical roller bearing according to claim 1, wherein: The left cover (2) and the locking cover (6) are respectively tightly attached with the sealing assemblies (5) at the adjacent two ends of the tapered roller bearing groups (3).
4. The profiled insert cutter having a conical roller bearing according to claim 1, wherein: The outer wall of the shell (7) is fixedly connected with a plurality of knife teeth (8).
5. The profiled insert cutter having a conical roller bearing according to claim 1, wherein: The contact angle of the tapered roller bearing group (3) is 24°, and the tapered roller bearing group (3) adopts special surface hardening treatment.