Tengzhou City will participate in the China International Machine Tool Show and will host mechanical...
Tengzhou City will participate in the China International Machine Tool Show and will host mechanical...
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Tengzhou City will participate in the China International Machine Tool Show and will host mechanical...
Liming Heavy Industry leads the development of domestic spring cone crusher
The world's first cone crusher patent was published in 1878, and it was not manufactured until 1898. The United States began to use cone crushers at the end of the 19th century. The spring cone crusher was designed by the Simmons brothers in Milwaukee, USA, hence the name Simmons cone crusher. The aircraft has a history of about a hundred years. Although it has been gradually improved and its structure is becoming more and more perfect, the basic structure has not changed significantly. On the basis of imitating the 2100 and 1650 spring cone crushers of the Soviet Union in 1954, our country designed and produced 1200 spring cone crushers by ourselves. In 1958, a large-scale 2200 spring cone crusher was designed and manufactured. After years of repeated research and practice, we have successively overcome the insufficient spring pressure of the old series, low parts strength and some shortcomings in the structure. The spring cone crushers are now mass-produced in five specifications: 600, 900, 1200, 1750, and 2200. 14 kinds of cavity.
Compared with similar crushers in advanced countries, the domestic spring cone crusher still has a gap in quality and performance. In order to catch up with the world's advanced level, the domestic heavy machinery factory introduced the Simmons and rotary disc type of Nordberg Company from the United States. Cone crusher technology, and cooperate to manufacture this series of cone crushers. The basic parameters specified in the new standard for cone crushers are also equivalent to Simmons cone crushers. Therefore, in the future, the spring cone crusher produced in China will be the Simmons crusher, and the old products will be gradually eliminated.
The Simmons cone crusher developed and manufactured by Liming Heavy Industry is based on the introduction and absorption of foreign technology, according to customer needs, based on the principle of laminated crushing and the concept of more breaking and less grinding. It is designed and developed with high swing frequency, optimized cavity shape and reasonable Modern high-performance spring cone crusher with stroke in one. Practice has proved that the CS series high-efficiency spring cone crusher has won the trust of global users with its excellent performance, reliable quality and high cost performance. It is an ideal substitute for traditional cone crushers. Liming Heavy Industry leads the development of domestic spring cone crushers with its own brand, technology and strength.
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The world's first cone crusher patent was published in 1878, and it was not manufactured until 1898. The United States began to use cone crushers at the end of the 19th century. The spring cone crusher was designed by the Simmons brothers in Milwaukee, USA, hence the name Simmons cone crusher. The aircraft has a history of about a hundred years. Although it has been gradually improved and its structure is becoming more and more perfect, the basic structure has not changed significantly. On the basis of imitating the 2100 and 1650 spring cone crushers of the Soviet Union in 1954, our country designed and produced 1200 spring cone crushers by ourselves. In 1958, a large-scale 2200 spring cone crusher was designed and manufactured. After years of repeated research and practice, we have successively overcome the insufficient spring pressure of the old series, low parts strength and some shortcomings in the structure. The spring cone crushers are now mass-produced in five specifications: 600, 900, 1200, 1750, and 2200. 14 kinds of cavity.
Compared with similar crushers in advanced countries, the domestic spring cone crusher still has a gap in quality and performance. In order to catch up with the world's advanced level, the domestic heavy machinery factory introduced the Simmons and rotary disc type of Nordberg Company from the United States. Cone crusher technology, and cooperate to manufacture this series of cone crushers. The basic parameters specified in the new standard for cone crushers are also equivalent to Simmons cone crushers. Therefore, in the future, the spring cone crusher produced in China will be the Simmons crusher, and the old products will be gradually eliminated.
The Simmons cone crusher developed and manufactured by Liming Heavy Industry is based on the introduction and absorption of foreign technology, according to customer needs, based on the principle of laminated crushing and the concept of more breaking and less grinding. It is designed and developed with high swing frequency, optimized cavity shape and reasonable Modern high-performance spring cone crusher with stroke in one. Practice has proved that the CS series high-efficiency spring cone crusher has won the trust of global users with its excellent performance, reliable quality and high cost performance. It is an ideal substitute for traditional cone crushers. Liming Heavy Industry leads the development of domestic spring cone crushers with its own brand, technology and strength.
Chinese and foreign spring companies gather in Dongguan to exchange new technologies
Yesterday, the opening ceremony of the 2011 National Spring Industry New Products, New Technologies and Scientific and Technological Information Exchange Exhibition was held in Dongguan for the first time. Dozens of Chinese and foreign spring manufacturing companies gathered to exchange new technologies.
The fair is jointly organized by the National Spring Standardization Technical Committee, the General Parts Product Quality Supervision and Testing Center of the Machinery Industry and other institutions. Well-known spring manufacturing companies and experts from Italy, Japan, and Taiwan attended the meeting.
The person in charge of a spring manufacturing company in Dongguan said that there are dozens of spring manufacturing companies in Dongguan, but the level of technology is generally not high. Many companies rely on price competition to survive. Companies that want to grow need to improve their technical level, and the fair is A good platform for technical exchange and learning.
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Yesterday, the opening ceremony of the 2011 National Spring Industry New Products, New Technologies and Scientific and Technological Information Exchange Exhibition was held in Dongguan for the first time. Dozens of Chinese and foreign spring manufacturing companies gathered to exchange new technologies.
The fair is jointly organized by the National Spring Standardization Technical Committee, the General Parts Product Quality Supervision and Testing Center of the Machinery Industry and other institutions. Well-known spring manufacturing companies and experts from Italy, Japan, and Taiwan attended the meeting.
The person in charge of a spring manufacturing company in Dongguan said that there are dozens of spring manufacturing companies in Dongguan, but the level of technology is generally not high. Many companies rely on price competition to survive. Companies that want to grow need to improve their technical level, and the fair is A good platform for technical exchange and learning.
Points to note before using spring dynamometer
1. Observe the range, that is, the measurement range. As shown in Figure 1, the range of the spring dynamometer is 5N. The measured force must be estimated before use. The measured force cannot exceed the range of the spring dynamometer, otherwise it will be damaged Spring dynamometer.
2. Observe the division value of the spring dynamometer, that is, the value represented between the smallest two scales, and understand the size of the division value, which is conducive to correct reading. As shown in Figure 1, the division value of the spring dynamometer is 0.2N.
3. Observe whether the pointer is pointing to the zero scale line. If it is not, adjust to zero, otherwise the measurement result will be inaccurate. As shown in Figure 2(d), the pointer is below the zero scale value when no force is applied, and the section above the pointer when reading after measurement The value is read in, causing the measurement result to be too large.
4. Before using the spring dynamometer, you should gently pull the hook back and forth several times, the purpose is to see if the spring is in contact with the shell, rubs, and is not flexible.
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1. Observe the range, that is, the measurement range. As shown in Figure 1, the range of the spring dynamometer is 5N. The measured force must be estimated before use. The measured force cannot exceed the range of the spring dynamometer, otherwise it will be damaged Spring dynamometer.
2. Observe the division value of the spring dynamometer, that is, the value represented between the smallest two scales, and understand the size of the division value, which is conducive to correct reading. As shown in Figure 1, the division value of the spring dynamometer is 0.2N.
3. Observe whether the pointer is pointing to the zero scale line. If it is not, adjust to zero, otherwise the measurement result will be inaccurate. As shown in Figure 2(d), the pointer is below the zero scale value when no force is applied, and the section above the pointer when reading after measurement The value is read in, causing the measurement result to be too large.
4. Before using the spring dynamometer, you should gently pull the hook back and forth several times, the purpose is to see if the spring is in contact with the shell, rubs, and is not flexible.
Air suspension: springs on wheels
The air suspension is structurally consistent with the traditional suspension, and is also composed of two major components, a spring and a shock absorber. The difference is that the air suspension spring is equipped with high-pressure air, and the softness and hardness of the spring can be changed according to different needs; the damping of the shock absorber is not static, and it is also adjustable. In other words, the biggest difference between air suspension and traditional suspension is that the characteristics of the suspension are variable, such as height, softness and hardness, etc. can be adjusted according to different road surfaces.
So the user has a lot of choice in the suspension characteristics setting. Models equipped with air suspension are mostly set to automatic, comfortable, normal and sports modes. Users can choose different modes according to the road conditions and their preferences.
In automatic mode, the on-board computer will adjust the height of the chassis and the softness of the suspension according to the vehicle speed and various dynamic parameters of the body. For example, the chassis will automatically lower at high speeds, and the suspension will become hard during intense driving. Of course, the computer calculates Not necessarily accurate, and the response is not necessarily very positive, so there are several other modes of choice.
When the comfort mode is selected, the chassis will be adjusted to the highest level and the suspension will become the softest. This mode is more suitable for driving on potholes and greatly improves driving comfort. If you drive violently at this time, the vehicle will shake more severely and the limit will be relatively low. In the normal mode, the height of the chassis and the hardness of the suspension are in the middle level, which is suitable for good pavement. In the sport mode, the chassis is adjusted to the lowest and the suspension becomes the hardest, suitable for intense driving, and the comfort is inferior to the previous two modes. From our experience, in addition to the sports mode, the chassis height can be manually adjusted in other modes to improve the passing of the vehicle, which is very user-friendly.
The emergence of air suspension gives a car multiple personalities and greatly improves road adaptability. It is an equipment that is beneficial to the car. As the air suspension technology is more sophisticated, the cost is high, and the maintenance cost is relatively expensive. Most of the air suspension is equipped on luxury cars, such as Mercedes-Benz S-class, Porsche Cayenne, Audi Q7, etc., but with the popularity of technology and cost Decrease, the current equipment has a downward trend, and the current minimum has been "decentralized" to some luxury brand models of around 500,000 yuan.
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The air suspension is structurally consistent with the traditional suspension, and is also composed of two major components, a spring and a shock absorber. The difference is that the air suspension spring is equipped with high-pressure air, and the softness and hardness of the spring can be changed according to different needs; the damping of the shock absorber is not static, and it is also adjustable. In other words, the biggest difference between air suspension and traditional suspension is that the characteristics of the suspension are variable, such as height, softness and hardness, etc. can be adjusted according to different road surfaces.
So the user has a lot of choice in the suspension characteristics setting. Models equipped with air suspension are mostly set to automatic, comfortable, normal and sports modes. Users can choose different modes according to the road conditions and their preferences.
In automatic mode, the on-board computer will adjust the height of the chassis and the softness of the suspension according to the vehicle speed and various dynamic parameters of the body. For example, the chassis will automatically lower at high speeds, and the suspension will become hard during intense driving. Of course, the computer calculates Not necessarily accurate, and the response is not necessarily very positive, so there are several other modes of choice.
When the comfort mode is selected, the chassis will be adjusted to the highest level and the suspension will become the softest. This mode is more suitable for driving on potholes and greatly improves driving comfort. If you drive violently at this time, the vehicle will shake more severely and the limit will be relatively low. In the normal mode, the height of the chassis and the hardness of the suspension are in the middle level, which is suitable for good pavement. In the sport mode, the chassis is adjusted to the lowest and the suspension becomes the hardest, suitable for intense driving, and the comfort is inferior to the previous two modes. From our experience, in addition to the sports mode, the chassis height can be manually adjusted in other modes to improve the passing of the vehicle, which is very user-friendly.
The emergence of air suspension gives a car multiple personalities and greatly improves road adaptability. It is an equipment that is beneficial to the car. As the air suspension technology is more sophisticated, the cost is high, and the maintenance cost is relatively expensive. Most of the air suspension is equipped on luxury cars, such as Mercedes-Benz S-class, Porsche Cayenne, Audi Q7, etc., but with the popularity of technology and cost Decrease, the current equipment has a downward trend, and the current minimum has been "decentralized" to some luxury brand models of around 500,000 yuan.
How to maintain a spring mattress
As long as they are used properly, high-quality spring mattresses are generally strong and durable and can last a long time. But you need to pay attention to:
1. Avoid excessive deformation of the mattress during transportation. Do not bend or fold the mattress, and do not directly use ropes to forcefully bind it.
2. Don't let the mattress be locally stressed, don't stand on the mattress for a long time or let children jump on the mattress, to avoid local compression that may cause fatigue and deformation and affect elasticity. To
3. Do not sit on the edge of the mattress for a long time. To
4. Regularly turn the mattress over and use it. It can be turned upside down or reversed. Generally, the family should change it every 3 months. To
5. In addition to using bed sheets, it is best to put on a mattress cover to prevent the mattress from getting dirty. Or choose a mattress cover for easy removal and washing. To
6. Remove the plastic packaging bag when using it to keep the mattress ventilated. Prevent the mattress from getting wet. Do not expose the mattress to the sun for too long. To
7. Pay attention to placing a cotton felt or bedding on the contact part of the spring mattress with the bed frame to reduce friction and extend the life. To
8. There must be a wooden board under the all-brown mattress, and it cannot be placed in the air.
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As long as they are used properly, high-quality spring mattresses are generally strong and durable and can last a long time. But you need to pay attention to:
1. Avoid excessive deformation of the mattress during transportation. Do not bend or fold the mattress, and do not directly use ropes to forcefully bind it.
2. Don't let the mattress be locally stressed, don't stand on the mattress for a long time or let children jump on the mattress, to avoid local compression that may cause fatigue and deformation and affect elasticity. To
3. Do not sit on the edge of the mattress for a long time. To
4. Regularly turn the mattress over and use it. It can be turned upside down or reversed. Generally, the family should change it every 3 months. To
5. In addition to using bed sheets, it is best to put on a mattress cover to prevent the mattress from getting dirty. Or choose a mattress cover for easy removal and washing. To
6. Remove the plastic packaging bag when using it to keep the mattress ventilated. Prevent the mattress from getting wet. Do not expose the mattress to the sun for too long. To
7. Pay attention to placing a cotton felt or bedding on the contact part of the spring mattress with the bed frame to reduce friction and extend the life. To
8. There must be a wooden board under the all-brown mattress, and it cannot be placed in the air.
Briefly describe the structure of the spring-type quick closing butterfly valve
The spring type quick closing butterfly valve is mainly composed of butterfly valve, hydraulic-spring drive device, hydraulic station and electric control box. When the valve is opened, the system issues a command (the electric control box is set to remote control), the hydraulic station works, and the hydraulic oil enters the bottom of the cylinder to push the piston to drive the butterfly valve to open, and the spring in the spring cylinder is compressed and stored. When an emergency occurs in the working system, the butterfly valve will receive an accident signal and will be closed quickly under the action of the spring. The closing time is 013~015s, thus protecting the working system and pipeline equipment.
Since the working medium of the quick-closing butterfly valve is a medium-high temperature gas, a special structure is adopted when the butterfly valve is designed.
(1) Butterfly plate The butterfly plate adopts a triple eccentric structure, so that during the opening and closing process of the butterfly valve, the sealing surface of the butterfly plate will immediately leave the sealing surface of the valve body at the moment of opening. During the closing process, only at the moment of closing, the sealing surface of the butterfly plate It will contact and compress the sealing surface of the valve body to ensure the seal, which completely eliminates the wear and abrasion between the two sealing surfaces. At the same time, the inclined cone structure has a self-positioning function to ensure the neutrality of the butterfly plate.
(2) The metal-graphite sandwich sealing ring of the floating sealing ring butterfly plate adopts a floating sealing form. When the temperature change of the butterfly valve occurs during installation or use, the floating sealing ring can compensate for the slight deformation of the valve body to make the butterfly valve seal Always keep it in the best condition.
(3) Shaft end temperature compensation mechanism due to the high operating temperature of the butterfly valve, taking into account the thermal expansion effect of the valve shaft, in order to prevent the valve shaft from being held up and the valve cannot be opened normally, a temperature compensation mechanism is added at the upper and lower shaft ends at the same time. Several sets of support gaskets with the same function as the disc spring are used to automatically adjust the size of the valve shaft caused by temperature to compensate for the unfavorable factors caused by excess deformation, so as to ensure that the butterfly plate does not deviate, the shaft end does not leak, and the tail The end is not damaged.
The normal working state (power-on state) of the quick-closing butterfly valve is normally open. Only when the system fails (power-off state) can it be quickly closed. According to this feature, the drive device must have an automatic reset function, that is, the drive device makes the butterfly valve open when the power is turned on, and the drive device automatically resets to close the butterfly valve when the power is off. There are many types of automatic reset drive devices. Considering the high safety performance requirements of butterfly valves, the structure of shift fork transmission and spring reset is adopted, which is mainly composed of box, shift fork, oil cylinder, piston, piston rod, spring and spring cylinder, etc. composition.
Since the fast closing time of the butterfly valve is required to be within 015s, considering the performance, the pin in the shift fork is made of alloy steel, and the contact part of the shift fork is equipped with a cylindrical roller bearing, which transmits the piston force of the cylinder to the shift in a rolling manner. Fork, in this way, not only reduces friction, increases life span, but also improves torque transmission efficiency. Due to the use of the spring action mechanism, the safety of the spring has been carefully considered. The independent safety protection screw makes it unnecessary to install and remove the spring on site, and to ensure the personal safety of the operator. The spring loading and disassembly are safe and convenient.
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The spring type quick closing butterfly valve is mainly composed of butterfly valve, hydraulic-spring drive device, hydraulic station and electric control box. When the valve is opened, the system issues a command (the electric control box is set to remote control), the hydraulic station works, and the hydraulic oil enters the bottom of the cylinder to push the piston to drive the butterfly valve to open, and the spring in the spring cylinder is compressed and stored. When an emergency occurs in the working system, the butterfly valve will receive an accident signal and will be closed quickly under the action of the spring. The closing time is 013~015s, thus protecting the working system and pipeline equipment.
Since the working medium of the quick-closing butterfly valve is a medium-high temperature gas, a special structure is adopted when the butterfly valve is designed.
(1) Butterfly plate The butterfly plate adopts a triple eccentric structure, so that during the opening and closing process of the butterfly valve, the sealing surface of the butterfly plate will immediately leave the sealing surface of the valve body at the moment of opening. During the closing process, only at the moment of closing, the sealing surface of the butterfly plate It will contact and compress the sealing surface of the valve body to ensure the seal, which completely eliminates the wear and abrasion between the two sealing surfaces. At the same time, the inclined cone structure has a self-positioning function to ensure the neutrality of the butterfly plate.
(2) The metal-graphite sandwich sealing ring of the floating sealing ring butterfly plate adopts a floating sealing form. When the temperature change of the butterfly valve occurs during installation or use, the floating sealing ring can compensate for the slight deformation of the valve body to make the butterfly valve seal Always keep it in the best condition.
(3) Shaft end temperature compensation mechanism due to the high operating temperature of the butterfly valve, taking into account the thermal expansion effect of the valve shaft, in order to prevent the valve shaft from being held up and the valve cannot be opened normally, a temperature compensation mechanism is added at the upper and lower shaft ends at the same time. Several sets of support gaskets with the same function as the disc spring are used to automatically adjust the size of the valve shaft caused by temperature to compensate for the unfavorable factors caused by excess deformation, so as to ensure that the butterfly plate does not deviate, the shaft end does not leak, and the tail The end is not damaged.
The normal working state (power-on state) of the quick-closing butterfly valve is normally open. Only when the system fails (power-off state) can it be quickly closed. According to this feature, the drive device must have an automatic reset function, that is, the drive device makes the butterfly valve open when the power is turned on, and the drive device automatically resets to close the butterfly valve when the power is off. There are many types of automatic reset drive devices. Considering the high safety performance requirements of butterfly valves, the structure of shift fork transmission and spring reset is adopted, which is mainly composed of box, shift fork, oil cylinder, piston, piston rod, spring and spring cylinder, etc. composition.
Since the fast closing time of the butterfly valve is required to be within 015s, considering the performance, the pin in the shift fork is made of alloy steel, and the contact part of the shift fork is equipped with a cylindrical roller bearing, which transmits the piston force of the cylinder to the shift in a rolling manner. Fork, in this way, not only reduces friction, increases life span, but also improves torque transmission efficiency. Due to the use of the spring action mechanism, the safety of the spring has been carefully considered. The independent safety protection screw makes it unnecessary to install and remove the spring on site, and to ensure the personal safety of the operator. The spring loading and disassembly are safe and convenient.
Strengthening of the compression spring
Round springs, due to their spiral geometry, are harder to strengthen than flat surface leaf springs. In addition, it is necessary to strictly evaluate the strengthening effect of the circular spring cross section, so as to fully understand the resistance of the circular spring to fatigue fracture.
The round springs are individually sent to the shot blasting room via a continuous conveyor chain system. A set of parallel roller tables are installed in the shot blasting room. While strengthening, the roller table keeps rolling, driving the round springs to move forward while rotating. This way of rotation allows the high-speed pill flow to pass between the rings of the circular spring and hit the metal surface of the inner ring, where the stress of the circular spring is most concentrated.
For applications with high productivity requirements, an enhanced device that can spray two round springs at the same time can be selected. The latest research and development result is based on the original shot blasting equipment, combined with multiple nozzles, used for more targeted and concentrated shot peening for the specific area of the round spring (stress concentration to please). To
Leaf spring strengthening
A continuous pass-through shot blasting equipment can be used to strengthen the leaf springs one by one, so that the geometric concave surface of the leaf spring is exposed to the high-speed shot flow. A typical model includes a throwing head used to project the top of the leaf spring, and a throwing head is installed on the side to spray the left and right sides of the leaf spring.
The passing speed of this standard leaf spring strengthening equipment is 10 feet per minute. If a higher production speed is required, the number of throwing heads can be increased and the motor frequency can be adjusted. Under working conditions, leaf springs are repeatedly affected by unidirectional bending stress, so they are sometimes stressed by stress. In the strengthening process, it is simulated that the leaf spring will be subjected to "stress strengthening" in the future use process, let it impose a "static stress" in the direction of the load, and perform shot peening on it. After the strengthening is completed, the applied static stress is released. Experiments show that stress strengthening can further extend the service life of leaf springs than conventional strengthening.
Suspension spring strengthening
Thanks to the high-stress and lightweight design, the weight of suspension springs has been greatly reduced in recent years, and it is very common that the stress of the suspension springs of new models>1000Mpa. The service of the spring under such high stress has exceeded the limit that the material can withstand, so it must be supplemented by other strengthening methods (such as shot/shot peening).
The main engine manufacturer adopts very strict test standards for automobile suspension springs. The longest test period is as long as 70 days (10 weeks). It should be a suspension spring that works under high stress conditions. Once the surface is subjected to stress corrosion That is, corrosion fatigue failure occurs. If the broken spring port punctures the tire, it may cause major safety and personal accidents.
Shot/shot peening is the most effective strengthening method for suspension springs. After proper shot peening, the fatigue life of high-stress springs can be increased by more than 5 times. At present, most of the shot/shot peening of suspension springs use steel wire cut blasting. Shot peening (different pellet diameters) is commonly used. The strength and depth of the spring surface compressive stress are important indicators to measure the effect of shot peening. The surface stress of good shot peening is at least above -600Mpa, and the distance from the surface is up to -800Mpa, and the surface pressure of the stress shot peening spring can reach above -800Mpa, and the distance from the surface to 50um can reach -1200Mpa.
At present, well-known spring manufacturers at home and abroad, such as Liaoyang Kesuo, etc., generally use a continuous pass-through roll cage strengthening equipment, and the workpiece is transported through a suspended conveyor chain. Each part must be in three shot blasting positions, and three shot blasting strengthening cycles are performed according to the set time. After the strengthening is completed, the throwing head stops, the discharge door is opened, the strengthened workpiece is automatically lifted out, the new workpiece enters, and the new cycle starts. The production capacity of this equipment can reach 500 pieces/hour.
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Round springs, due to their spiral geometry, are harder to strengthen than flat surface leaf springs. In addition, it is necessary to strictly evaluate the strengthening effect of the circular spring cross section, so as to fully understand the resistance of the circular spring to fatigue fracture.
The round springs are individually sent to the shot blasting room via a continuous conveyor chain system. A set of parallel roller tables are installed in the shot blasting room. While strengthening, the roller table keeps rolling, driving the round springs to move forward while rotating. This way of rotation allows the high-speed pill flow to pass between the rings of the circular spring and hit the metal surface of the inner ring, where the stress of the circular spring is most concentrated.
For applications with high productivity requirements, an enhanced device that can spray two round springs at the same time can be selected. The latest research and development result is based on the original shot blasting equipment, combined with multiple nozzles, used for more targeted and concentrated shot peening for the specific area of the round spring (stress concentration to please). To
Leaf spring strengthening
A continuous pass-through shot blasting equipment can be used to strengthen the leaf springs one by one, so that the geometric concave surface of the leaf spring is exposed to the high-speed shot flow. A typical model includes a throwing head used to project the top of the leaf spring, and a throwing head is installed on the side to spray the left and right sides of the leaf spring.
The passing speed of this standard leaf spring strengthening equipment is 10 feet per minute. If a higher production speed is required, the number of throwing heads can be increased and the motor frequency can be adjusted. Under working conditions, leaf springs are repeatedly affected by unidirectional bending stress, so they are sometimes stressed by stress. In the strengthening process, it is simulated that the leaf spring will be subjected to "stress strengthening" in the future use process, let it impose a "static stress" in the direction of the load, and perform shot peening on it. After the strengthening is completed, the applied static stress is released. Experiments show that stress strengthening can further extend the service life of leaf springs than conventional strengthening.
Suspension spring strengthening
Thanks to the high-stress and lightweight design, the weight of suspension springs has been greatly reduced in recent years, and it is very common that the stress of the suspension springs of new models>1000Mpa. The service of the spring under such high stress has exceeded the limit that the material can withstand, so it must be supplemented by other strengthening methods (such as shot/shot peening).
The main engine manufacturer adopts very strict test standards for automobile suspension springs. The longest test period is as long as 70 days (10 weeks). It should be a suspension spring that works under high stress conditions. Once the surface is subjected to stress corrosion That is, corrosion fatigue failure occurs. If the broken spring port punctures the tire, it may cause major safety and personal accidents.
Shot/shot peening is the most effective strengthening method for suspension springs. After proper shot peening, the fatigue life of high-stress springs can be increased by more than 5 times. At present, most of the shot/shot peening of suspension springs use steel wire cut blasting. Shot peening (different pellet diameters) is commonly used. The strength and depth of the spring surface compressive stress are important indicators to measure the effect of shot peening. The surface stress of good shot peening is at least above -600Mpa, and the distance from the surface is up to -800Mpa, and the surface pressure of the stress shot peening spring can reach above -800Mpa, and the distance from the surface to 50um can reach -1200Mpa.
At present, well-known spring manufacturers at home and abroad, such as Liaoyang Kesuo, etc., generally use a continuous pass-through roll cage strengthening equipment, and the workpiece is transported through a suspended conveyor chain. Each part must be in three shot blasting positions, and three shot blasting strengthening cycles are performed according to the set time. After the strengthening is completed, the throwing head stops, the discharge door is opened, the strengthened workpiece is automatically lifted out, the new workpiece enters, and the new cycle starts. The production capacity of this equipment can reach 500 pieces/hour.