CN211145186U - Automobile brake drum - Google Patents
Automobile brake drum Download PDFInfo
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- CN211145186U CN211145186U CN201921753716.3U CN201921753716U CN211145186U CN 211145186 U CN211145186 U CN 211145186U CN 201921753716 U CN201921753716 U CN 201921753716U CN 211145186 U CN211145186 U CN 211145186U
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Abstract
The utility model discloses an automobile brake drum, automobile brake drum include flange end and working section, and the working section outer wall is equipped with the round boss, the working section wall thickness is 10-15mm, be equipped with the changeover portion between working section and flange end, set up the louvre on the changeover portion, this kind of new louvre structure can prevent that impurity gets into inside the brake drum to influence the condition in brake shoe life-span, the prevention is because the poor or the trouble that becomes invalid of braking effect that the oil leak arouses because of the oil pipe way breaks in the brake drum working process. The utility model discloses established and used coefficient of friction as standard selection material to combine new processing technology, made brake drum preparation material, product structure and heat treatment process organic combination, the product of making can be with the wall thickness control of braking in 10-15mm, compare and brake more than or equal to 20mm wall thickness in traditional, can alleviate 20% -25% in product weight. Not only does not increase the cost, but also has higher strength, wear resistance, service life and safety.
Description
Technical Field
The utility model relates to a brake drum and manufacturing method thereof especially relate to an automobile brake drum and manufacturing method thereof.
Background
The automobile brake drum is the most important and the most critical safety part in an automobile brake system, is used as a brake friction piece in the automobile brake system, has higher safety performance requirements, and drives a friction plate to expand outwards through a brake block when the automobile brakes to generate friction with the brake drum so as to convert kinetic energy of the automobile into heat energy, namely, the brake and the deceleration are realized by the friction force generated by pressing the brake block on the brake wheel. Seen through the structure principle to the brake drum in the course of the work, the brake drum can bear pressure in the twinkling of an eye local of braking, bears the pulling force on the whole, and in the braking, produces powerful frictional force between brake shoe and the brake drum, so produce the heat and make brake drum temperature promote rapidly at the in-process of rubbing. Therefore, in order to meet the above characteristics of the brake drum, the required material should have good high temperature performance, especially high thermal fatigue resistance, in addition to good normal temperature performance such as wear resistance, strength, toughness and the like.
The automobile brake drum product is a wear-consuming part, the market demand is large, the annual demand is about 10 hundred million, and the consumption is about 4000 million tons, but the current automobile brake drum has the following problems:
1. defects caused by material selection:
(1.1) gray iron: at present, the brake drum is known to be made of HT200 or HT250 materials, the structures of the brake drum are flake graphite and pearlite, the flake graphite has serious cutting cracks on a matrix, and stress concentration is easily caused at the sharp corners of the graphite, so the carbon content of the type is low, the structures are thick, the strength and hardness are also low, the mechanical property does not reach the standard, casting defects exist, the stress of a casting is overlarge, cracking and abrasion are easy to occur seriously in the using process, thermal fatigue cracks are easy to generate, the service life is short, and the service life is usually about 1-2 kilometers. The wall thickness of the product made of the material is more than or equal to 15mm, and the weight of the product is heavier, about 55-65 KG.
(1.2) Q235-brand alloy steel material: some steel drums are also available on the market, and because the steel drums are made of Q235-grade materials under the influence of manufacturing cost, the steel drums are better than cast iron in strength, but the wear resistance and the heat resistance of the steel drums are not as good as those of common cast iron, the steel drums are easy to deform in the actual use process, and the outer tension of a working surface causes the braking effect to be poor.
2. The main failure modes of the brake drum include abrasion, fracture, fatigue crack, flange bottom drop and the like. The brake drum bears pressure locally at the moment of braking and bears tension totally, strong friction force is generated between the brake drum and the brake shoe, and the temperature of the working surface of the brake drum reaches 400-500 ℃ due to heat generated by friction. With the increase of the speed of the automobile, the increase of the load capacity of the automobile, the great investment of roads in mountainous areas and the aggravation of traffic jam, when the brake frequently works, the local temperature of the brake drum is higher, the brake drum is in a severe thermal fatigue state, and when the brake drum is in the thermal fatigue state, some users additionally install water drenchers to suddenly drop the surface temperature of the brake drum, so that cracks are generated on the surface of the brake drum.
3. In order to discharge the heat generated by the brake drum in the braking process, some manufacturers set heat dissipation holes with different structures on the surface of the working section of the brake drum, but the hole positions basically penetrate through the inner wall and the outer wall of the working section in the working section and the hole opening direction, so that the effect of cooling is achieved, and other adverse effects are also generated. For example, some companies open heat dissipation holes, holes are directly formed in the working section perpendicular to the working surface, impurities enter the brake drum to affect the service life of the brake shoe, and meanwhile, the hole opening direction is perpendicular to the working surface of the brake drum, so that the brake shoe can be subjected to transverse shearing force at the hole opening position when being subjected to friction braking with the brake drum in the working process of the brake system, and the abrasion of the brake shoe is accelerated.
4. The relationship between the friction coefficient and the hardness is not considered.
(4.1) the magnitude of the friction force is a key for influencing the braking of the automobile, the magnitude of the friction force is influenced by the friction coefficient of the brake drum, and if the friction coefficient is too small, the friction force is insufficient, so that the side length of the braking distance is caused; if the friction coefficient is too large, the brake drum can be locked, and the automobile can slip or roll over. However, the problem of the friction coefficient is not considered in the current brake drum patent.
(4.2) for metal materials, the friction coefficient is inversely proportional to the hardness, if the hardness of the material is increased, the friction coefficient is reduced, the braking effect is obviously poor, the situation that spring feet are generated due to the fact that the hardness of a brake drum is too high in the process of stepping on a brake occurs, and a huge safety risk occurs. However, if only the friction coefficient is considered, the hardness of the material is not enough, and if the CrMo alloy material is selected, the brake drum made of the material has the problem of plastic deformation due to good plasticity of the material, and the service life of the brake drum is easily reduced due to deformation in the working process.
In conclusion, the automobile brake drum on the market at present cannot meet the market requirements of heavy load and high speed of automobiles under new situations, particularly the requirements of the brake drum of a heavy truck, due to the problems of structure, material selection and process. Therefore, the strength, wear resistance, service life and safety of the brake drum need to be further improved, and the weight of the brake drum needs to be reduced, and the development of the performance indexes is greatly limited for the common gray iron. Therefore, the development of new materials and new processes for replacing the existing brake drum products is necessary.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a solve above-mentioned problem, choose for use the low carbon alloy steel material to cast, change product structure and production technology to effectively improve the automobile brake drum of intensity, wearability, life and the security of brake drum and manufacturing method thereof.
In order to achieve the above purpose, the utility model adopts the technical scheme that: the utility model provides an automobile brake drum, includes flange end and working section, and the center pin of the two is coaxial, the working section outer wall is equipped with the round boss, the working section wall thickness is 10-15mm, be equipped with the changeover portion of a hollow round platform form between working section and the flange end, the big end connection work of changeover portion, tip flange end, the changeover portion outer wall is equipped with an annular district coaxial with the working section, evenly be provided with the several louvre that runs through to its inner wall from the changeover portion outer wall on the annular district, the louvre is parallel on the center pin, and the cross section is the rectangle, changeover portion and working section integrated into one piece, the two adopts the rigidity to be HRC34-HRC38 CrMo alloy material to make.
Preferably, the method comprises the following steps: the heat dissipation holes are uniformly distributed along the tangential direction of the annular area, the number of the heat dissipation holes is 8-12, and the cross section size is 10mm x 30 mm.
Preferably, the method comprises the following steps: the CrMo alloy material is 35CrMo alloy.
A manufacturing method of an automobile brake drum comprises the following steps:
(1) determining a friction coefficient range of a brake drum, and determining the quenching and tempering hardness of a CrMo alloy according to the friction coefficient range, wherein the friction coefficient range is 0.37-0.4, the CrMo alloy material is 35CrMo alloy steel, and the quenching and tempering hardness is HRC34-HRC 38;
(2) continuously performing metal melting and pouring by using the CrMo alloy material selected in the step (1) to prepare a semi-finished product, wherein the semi-finished product comprises a working section, a transition section, a flange end, a heat dissipation hole and a boss;
(3) carrying out sand removal and polishing on the semi-finished product obtained in the step (2);
(4) quenching and tempering the semi-finished product obtained in the step (3);
(5) carrying out shot blasting treatment on the semi-finished product obtained in the step (4);
(6) carrying out surface quenching on the semi-finished product obtained in the step (5);
(7) and (4) tempering and machining the semi-finished product obtained in the step (6) to obtain the product.
Preferably, the method comprises the following steps: the quenching and tempering treatment in the step (4) is specifically as follows: heating to 900-930 deg.C, water cooling to below 50 deg.C, heating to 500-550 deg.C, and medium-temperature tempering to make the hardening and tempering hardness reach HRC 34-38.
Preferably, the method comprises the following steps: in the step (5), during surface quenching, the quenching hardness is HRC55-60, and the depth of a quenching layer is 2 mm.
The utility model discloses mainly improve louvre structure, manufacturing method.
Wherein, about the improvement of louvre structure, increase a changeover portion between working section and flange end, the changeover portion is hollow round platform shape, so surface and inner wall are the inclined plane, and we run through the inclined plane back from the inclined plane front and set up the louvre, i.e. run through the louvre to its inner wall from the changeover portion outer wall, the louvre is at first not located the working section, and the direction is parallel with the center pin of working section, like: (1) the heat dissipation holes can absorb heat generated by the brake drum in the braking process through expansion of heated gas and generate negative pressure to be discharged, so that the heat is taken away to reduce the temperature of the brake drum; (2) meanwhile, the brake shoe is not arranged on the working section and cannot penetrate through the inside and the outside of the working section, so that the condition that impurities enter the brake drum to influence the service life of the brake shoe can be prevented; (3) the brake drum can prevent the fault of poor braking effect or failure caused by oil leakage due to the rupture of an oil pipeline in the working process of the brake drum.
The improvement of the manufacturing method is mainly reflected in the following points:
firstly, the method comprises the following steps: the utility model provides an use "coefficient of friction" as the thinking that the standard carries out the election material. In order to ensure that the brake drum has a good braking effect, the working surface of the cast steel material needs to have a good friction coefficient, so that in order to ensure that the braking function of the newly selected material is not affected, the brake drum working environment simulation experiment is carried out on the friction coefficients of the materials with different hardness to obtain a relation table of the materials with different hardness and the friction coefficient, and the following table 1 can be specifically seen:
table 1: relation table of materials with different hardness and friction coefficient
As the cast iron brake drum is a product which is proved to be mature in market, in order to ensure that the brake drum made of a new material does not influence the braking performance, the friction coefficient of the HT250 material is taken as the standard of the new material, the known HT250 hardness requirement is HB190-210, the friction coefficient in the range is 0.38-0.40, and the heat treatment hardness requirement of the material 35CrMo of the utility model is HRC 34-38.
Of course, the material selection method of the 30CrMo and 42CrMo alloy is the same as the above method, and only needs to find the corresponding friction coefficient range of the alloy and match the corresponding heat treatment hardness requirement.
Secondly, the method comprises the following steps: the material still needs to combine the technology improvement, and the quenching and tempering can increase the hardness of material, nevertheless can reduce the coefficient of friction of material, so the quenching and tempering that can not be tasteless, the utility model discloses at first make product bulk hardness satisfy coefficient of friction's standard through the quenching and tempering, processes such as surface induction quenching are deuterogamied, strengthen product surface strength and the ability of resisting plastic deformation to increase the holistic intensity of product and the ability of resisting plastic deformation, finally make the utility model discloses the product. The product prepared by the method can effectively ensure the friction coefficient and simultaneously ensure the strength and the plastic deformation resistance.
Compared with the prior art, the utility model has the advantages of:
(1) structurally: the novel heat dissipation hole structure is adopted, so that the heat dissipation effect is good, impurities can be prevented from entering the interior of the brake drum, the service life of the brake shoe is influenced, and the fault that the brake effect is poor or the brake fails due to oil leakage caused by breakage of an oil pipeline in the working process of the brake drum is prevented.
(2) Adopts a new processing technology: the material is selected through parameters such as friction coefficient, hardening and tempering hardness and the like, and the material is subjected to hardening and tempering, surface quenching and the like by combining a new process, so that the contradiction between the friction coefficient and the strength is overcome, the strength and the plastic deformation resistance of the product are improved while the friction force and the braking effect are ensured, and the product has better strength, wear resistance, service life and safety.
(3) The wall thickness of the product made of the new material and the new process can be controlled within 10-15mm, and compared with the wall thickness of more than or equal to 20mm in the traditional braking, the wall thickness of the product can be reduced by 20-25% in weight. Therefore, although the material price of the utility model is higher than the common material on the market, the consumption is less and the cost is not increased.
Drawings
FIG. 1 is a perspective view of the utility model;
FIG. 2 is a right side view of FIG. 1;
FIG. 3 is a cross-sectional view A-A of FIG. 1;
FIG. 4 is a perspective view of the louvers of FIG. 3.
In the figure: 1. a flange end; 2. a working section; 3. a boss; 4. a transition section; 5. and (4) heat dissipation holes.
Detailed Description
The present invention will be further explained with reference to the accompanying drawings.
Example 1: referring to fig. 1 to 4, an automobile brake drum comprises a flange end 1 and a working section 2, wherein central axes of the flange end 1 and the working section 2 are coaxial, a circle of boss 3 is arranged on the outer wall of the working section 2, the wall thickness of the working section 2 is 10-15mm, a hollow truncated cone-shaped transition section 4 is arranged between the working section 2 and the flange end 1, the large end of the transition section 4 is connected with the flange end 1, the small end of the transition section 4 is connected with the flange end 1, the outer wall of the transition section 4 is provided with an annular area coaxial with the working section 2, a plurality of heat dissipation holes 5 penetrating from the outer wall of the transition section 4 to the inner wall of the transition section are uniformly arranged on the annular area, the heat dissipation holes 5 are parallel to the central axis, the cross section is rectangular, the transition section 4 and the working section 2 are integrally formed, and the transition section.
In this embodiment: the heat dissipation holes 5 are uniformly distributed along the tangential direction of the annular area, the number of the heat dissipation holes is 8-12, and the cross section size is 10mm x 30 mm; the CrMo alloy material is 35CrMo alloy.
A manufacturing method of an automobile brake drum comprises the following steps:
(1) determining a friction coefficient range of a brake drum, and determining the quenching and tempering hardness of a CrMo alloy according to the friction coefficient range, wherein the friction coefficient range is 0.37-0.4, the CrMo alloy material is 35CrMo alloy steel, and the quenching and tempering hardness is HRC34-HRC 38;
(2) continuously performing metal melting and pouring by using the CrMo alloy material selected in the step (1) to prepare a semi-finished product, wherein the semi-finished product comprises a working section 2, a transition section 4, a flange end 1, a heat dissipation hole 5 and a boss 3;
(3) carrying out sand removal and polishing on the semi-finished product obtained in the step (2);
(4) and (4) quenching and tempering the semi-finished product obtained in the step (3), specifically: heating to 900-930 ℃, then cooling to below 50 ℃, heating to 500-550 ℃ and tempering at medium temperature to make the quenching and tempering hardness reach HRC 34-38;
(5) carrying out shot blasting treatment on the semi-finished product obtained in the step (4);
(6) carrying out surface quenching on the semi-finished product obtained in the step (5), wherein the quenching hardness is HRC55-60 and the depth of a quenching layer is 2mm during the surface quenching;
(7) and (4) tempering and machining the semi-finished product obtained in the step (6) to obtain the product.
And (7) machining mainly comprises turning an inner hole, turning an outer circle, turning the end face of the flange end 1, drilling the end face of the flange end 1 and the like.
Example 2: based on the basis of example 1, for a better determination scheme, we have conducted a large number of comparative experiments when selecting materials, for example, the above-mentioned common gray iron material HT250, Q235 brand steel material, and the utility model discloses the 35CrMo material of chooseing for use, obtained the wear resistance of above-mentioned three kinds of materials and tensile strength's test data table, be following table 2, table 3:
table 2: wear-resistant test data table
In Table 2, the rings of material used for the test were 20mm thick,
the inner ring diameter was tested using friction plates of the same material. From the data, the 35CrMo material is obviously superior to the first two materials.
Table 3: tensile strength comparison table of test bar (MPa)
| Name of item | | Q235 | 35CrMo | |
| 1 | 262 | 383 | 1081 | |
| 2 | 253 | 411 | 1190 | |
| 3 | 274 | 396 | 1072 | |
| 4 | 255 | 378 | 1065 | |
| 5 | 259 | 421 | 1058 | |
| 6 | 277 | 434 | 1106 | |
| 7 | 266 | 391 | 1078 | |
| 8 | 271 | 422 | 998 | |
| 9 | 252 | 386 | 1003 | |
| 10 | 263 | 432 | 1012 |
In table 3, it can be calculated from the strength calculation formula σ ═ Fb/So that the 35CrMo material can bear 2.5 times of the Q235 material and 4 times of HT250 material under the same wall thickness condition.
Therefore, in this embodiment, we specifically select 35CrMo material.
The manufacturing method of example 2 is the same as example 1.
The following comparison table 4 is obtained by comparing various parameters of the brake drum made of the materials and the manufacturing method of the embodiment with the brake drum made of HT250 material and Q235 material purchased from the market:
table 4: three-material brake drum parameter comparison table
Can know from table 4, adopt the utility model discloses two kinds of car brake drums that car brake drum tensile strength who makes is higher than commonly used on the market far away.
Example 3:
in order to verify the heat dissipation effect of a product with a new structure, a brake drum with the new structure is brought to a Guizhou six-disc water mountain road for brake test, the mountain road is a continuous downhill road section, the gradient is greater than 20 degrees, the length is 38 kilometers, 20 brake drums are used in total, an infrared thermometer is used for measuring the temperature, and details are as follows:
the test temperature shows that the temperature range of the steel drum with the heat dissipation hole 5 is 150-165 ℃ compared with the temperature of the iron drum without the heat dissipation hole is 230-300 ℃, and the brake drum with the new structure is obviously lower than the traditional drum. The heat dissipation hole 5 can take away 64% of heat of the brake drum by combining test data and then calculating according to a specific heat capacity formula Q-cm delta t.
In summary, the utility model provides a thinking of selecting materials based on friction coefficient, selects CrMo alloy materials which meet the requirement of friction coefficient and have higher cost, and combines the manufacturing method of the utility model to thin the wall thickness of the brake, thereby saving more materials and not increasing the material cost; and owing to adopted the utility model discloses a method, the brake drum that makes not only the cost can not increase, still has higher intensity, wearability, life and security.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
Claims (3)
1. The utility model provides an automobile brake drum, includes flange end and working section, and the two center pin is coaxial, the working section outer wall is equipped with round boss, its characterized in that: the wall thickness of the working section is 10-15mm, a hollow truncated cone-shaped transition section is arranged between the working section and the flange end, the large end of the transition section is connected for working, the small end of the transition section is connected with the flange end, the outer wall of the transition section is provided with an annular area coaxial with the working section, a plurality of heat dissipation holes penetrating from the outer wall of the transition section to the inner wall of the transition section are evenly arranged on the annular area, the heat dissipation holes are parallel to the central axis, the cross section of the heat dissipation holes is rectangular, and the transition section and the working section are integrally formed and made of CrMo alloy materials with the hardness of HRC34-HRC 38.
2. The automotive brake drum of claim 1, wherein: the heat dissipation holes are uniformly distributed along the tangential direction of the annular area, the number of the heat dissipation holes is 8-12, and the cross section size is 10mm x 30 mm.
3. The automotive brake drum of claim 1, wherein: the CrMo alloy material is 30CrMo, 35CrMo or 42CrMo alloy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921753716.3U CN211145186U (en) | 2019-10-18 | 2019-10-18 | Automobile brake drum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921753716.3U CN211145186U (en) | 2019-10-18 | 2019-10-18 | Automobile brake drum |
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| CN211145186U true CN211145186U (en) | 2020-07-31 |
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| CN201921753716.3U Active CN211145186U (en) | 2019-10-18 | 2019-10-18 | Automobile brake drum |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110645292A (en) * | 2019-10-18 | 2020-01-03 | 绵阳市联重科技有限公司 | Automobile brake drum and manufacturing method thereof |
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- 2019-10-18 CN CN201921753716.3U patent/CN211145186U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110645292A (en) * | 2019-10-18 | 2020-01-03 | 绵阳市联重科技有限公司 | Automobile brake drum and manufacturing method thereof |
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