CN110512155B

CN110512155B - Variable cross-section spring blank and processing tool and processing technology thereof

Info

Publication number: CN110512155B
Application number: CN201910623419.5A
Authority: CN
Inventors: 夏泽民; 周涛; 潘逸明; 缪勤竹
Original assignee: Jiangsu Changling Hydraulic Co ltd
Current assignee: Jiangsu Changling Hydraulic Co ltd
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2020-06-26
Anticipated expiration: 2039-07-11
Also published as: CN110512155A

Abstract

The invention discloses a variable cross-section spring blank, a processing tool and a processing technology, wherein the spring blank is a spiral spring blank, the cross section of the spiral spring blank is oval, the cross section of the spiral spring blank along the axial direction is olive-shaped, and a carbon fiber mandrel embedded in a spring material is arranged along the center of the oval. The processing tool comprises a ceramic forming pipe with one end provided with a conical opening, a carbon fiber wire guide pipe which is coaxial with the ceramic forming pipe is arranged on the position, away from the opening end, of the end, located at the conical opening, of the ceramic forming pipe, a pay-off reel is arranged in front of the other opening end of the guide pipe, and a spring blank cooling mechanism and a carbon fiber wire traction mechanism are arranged at the other end of the ceramic forming pipe. The processing technology comprises the steps that a pay-off reel, a carbon fiber wire guide pipe, a ceramic forming pipe, a spring blank cooling mechanism and a carbon fiber wire traction mechanism in a tool are sequentially installed on a workbench, and quantitative molten spring steel and steel are poured into the ceramic forming pipe through a metal liquid pouring port with a conical opening of the ceramic forming pipe.

Description

Variable cross-section spring blank and processing tool and processing technology thereof

Technical Field

The invention relates to the technical field of spring processing and manufacturing, in particular to a heavy spring, and specifically relates to a spring blank with a variable cross section and a carbon fiber mandrel arranged in the center, a processing tool for the spring blank and a processing technology for the spring blank.

Background

In recent years, the development of heavy machinery towards light weight is urgently required due to the world energy crisis, the price rise of oil and environmental problems, and the aim of realizing light structure by using light materials (or new materials) to replace traditional materials is generally achieved, so that the further improvement of the fuel utilization rate is one of the hot spots of research.

Lightweight materials (or new materials) including high strength steel, aluminum, magnesium and titanium alloys, plastics and composites, and the like; compared with metal materials, carbon fiber composite materials such as carbon fiber reinforced plastics (hereinafter, referred to as CFRP) have advantages of light weight, high rigidity, high strength, high fatigue resistance, wear resistance, vibration resistance and shock and vibration absorption, and have a specific modulus 5 times higher and 3 times higher than those of steel and aluminum alloys, but have a small specific gravity, and the weight per unit volume is only 20% of that of steel. In addition, carbon fiber composite materials have high corrosion resistance and low thermal expansion, are more durable than steel, and are not easily rusted, and heavy equipment manufacturers have actively made attempts to apply light-weight composite materials to interior materials of heavy equipment, housings, springs, and the like.

However, most of the conventional springs (i.e., coil springs) are made by winding only a metal material (steel material), and the manufacturing process is complicated; the spring is mainly characterized in that the spring stores energy and releases energy through a certain conversion mode by virtue of the physical properties of metal materials, so that the spring with the functions of shock absorption and buffering is manufactured, and is applied to parts of various mechanisms and industrial machinery, such as engineering machinery, locomotives and aerospace (CN 103573892A). To meet the demands of industry development, springs made of metal materials alone have been difficult to meet the demands of use, and a bottleneck has been reached from the design, material selection, manufacture and inspection of metal springs. Therefore, it is a trend in industry to prepare a helical spring from a carbon fiber composite material instead of a metal helical spring.

Many researchers have attempted to make coil type springs using CFRP. However, because CFRP is susceptible to compressive or shear stress, it is difficult to produce a helical spring from a single carbon fiber tow to generate sufficient tension to provide a spring body with a rebound force (CN 103388642 a). In addition, the spring made of the carbon fiber composite material faces some challenges, such as poor elasticity, fragility and high anisotropy, which are inherently unsuitable for the spring, so that the manufactured carbon fiber composite material spring has small deformation, low elastic coefficient and small load bearing capacity. Therefore, the special high tensile strength of the carbon fiber composite material is utilized to design a composite material spring with a special structure to achieve large bearing capacity (WO 2014/014481A 1; WO 02/099307A 1; US

2852424A; US 4773633 a; US 8857801B 2; US 7857294B 2; US 5685525 a; US 4260143A; CN 104690984A; CN 103221199 a). Therefore, it is critical to develop a coil spring structure of carbon fiber composite material that can achieve weight reduction, has excellent durability, and replaces a coil spring made of only a metal material.

The currently mentioned manufacturing method for manufacturing the fiber reinforced composite material helical spring is poor, the operation difficulty is high, the labor hour is consumed, the equipment capital investment is required to be high, the material waste is serious, and the cost of the produced carbon fiber composite material part is high. (EP0637700B 1; US 8490530B 2; CN 1480658A; CN 1651795A; CN 1232931A; CN 101439580A)

In addition, the existing forming die for manufacturing the fiber reinforced composite material spring (EP 2647481A 1; US 4434121A; US 5988612A; US 4473217A; US 6986203B 2; CN 102909870A) has the disadvantages of complex design process, high die opening cost, difficult die filling and demoulding and low production efficiency. In the process of closing and heating the mould, bubbles exist on the surface or inside of the product due to uneven soaking of the carbon fibers by the resin, so that the surface is uneven. In the production process, because resin reaction generates internal stress, the internal stress can not be counteracted without the help of external force, the strength performance of the product can be greatly influenced, and the service life of the product can be directly influenced.

In addition, one side of the cross section of the existing spiral spring is circular, and the shape and the size of the interface are always unchanged. However, in the using process of the spring, the external forces received by different parts of the spring are different, and the vibration frequency and the vibration amplitude of the different parts of the spring are also different. Therefore, the spring is most easily damaged at the part with larger stress, higher vibration frequency and larger amplitude.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a variable cross-section spring blank which is simple in structure, light in weight, high in strength, long in service life, strong in corrosion resistance and easy to machine, a machining tool for the spring blank and a machining process for the spring blank.

In order to achieve the purpose, the invention provides a spring blank forming tool which can be used for simply, quickly and inexpensively pre-burying a carbon fiber wire in the center of spring steel to form a blank for processing a spiral spring, wherein the center of the blank is provided with a carbon fiber mandrel spring blank forming tool, the tool comprises a ceramic forming pipe, one end of the ceramic forming pipe is provided with a conical opening from small to large, the cross section of the ceramic forming pipe is oval, a carbon fiber wire guide pipe coaxial with the ceramic forming pipe is arranged at the position, 30-50 mm away from the large end of the conical opening, of the ceramic forming pipe, one open end of the carbon fiber wire guide pipe faces the large end of the conical opening of the ceramic forming pipe, a pay-off reel for the carbon fiber wire is arranged in front of the other open end of the carbon fiber wire guide pipe, and the other end of the; the tool is also provided with a lead needle which is used for leading out the carbon fiber wire from the pay-off reel, then penetrating through the carbon fiber wire guide tube and the ceramic forming tube and clamping the carbon fiber wire on the traction mechanism of the carbon fiber wire.

In order to enable the carbon fiber mandrel to be positioned at the central part of the spring leather, the spring steel must be melted into liquid, then the melted metal liquid is poured into a high-temperature resistant ceramic forming tube with a carbon fiber wire prefabricated in the center through a pouring gate, the length of the pipeline is not too long, so that the metal liquid flowing into the pipeline is prevented from being retained and cannot form smooth flowing, and the preferable technical scheme is that a metal liquid pouring gate is arranged on one side of the ceramic forming tube, which is positioned at the large end of the conical opening.

According to a further preferable technical scheme, the spring blank is a spiral spring blank, the cross section of the spiral spring blank is oval, the cross section of the spiral spring blank along the axial direction is olive-shaped, and a carbon fiber mandrel embedded in the spring material is arranged along the center of the oval.

In order to improve the tensile strength of the spring and facilitate the forming of the spiral spring, the preferred technical scheme is that the carbon fiber mandrel embedded in the spring blank is a carbon fiber wire or a plurality of carbon fiber wires.

In order to enable the spiral spring to have a high supporting effect and absorb the self vibration of the spring in the movement process, the technical scheme is further preferably that the plurality of carbon fiber wires are in a torsional shape, and the number of torsional turns is 15-60 turns/m.

In order to use the spring with the carbon fiber mandrel in heavy engineering machinery, a further preferable technical scheme is that the material of the spring blank wrapped outside the mandrel is spring steel.

To is coming to

In order to embed a carbon fiber wire in the center of spring steel simply, quickly and at low cost to form a blank for machining a spiral spring, the invention also provides a machining process of the spring blank with the carbon fiber mandrel in the center, wherein the machining process of the spring blank comprises the following process steps:

s1, sequentially installing a pay-off reel of the carbon fiber wire, a carbon fiber wire guide tube, a ceramic forming tube, a spring blank cooling mechanism and a carbon fiber wire traction mechanism on a workbench;

s2, fixing the end part of the carbon fiber wire at one end of a thread guiding needle in the tool, sequentially penetrating the other end of the thread guiding needle through a carbon fiber wire guiding tube and a ceramic forming tube, and then detaching one end of the carbon fiber wire from one end of the thread guiding needle and clamping the carbon fiber wire on a traction mechanism of the carbon fiber wire;

s3, pouring a certain amount of molten spring steel into the ceramic forming tube from a molten metal pouring gate at the large end side of the conical opening of the ceramic forming tube in the tool set forth in claim 7;

s4, when the molten metal extends out from the other end of the ceramic forming tube, starting a spring blank cooling mechanism in the tool to rapidly cool the formed molten metal extending out of the ceramic forming tube;

s5, when the spring blank cooling mechanism is started, the traction mechanism of the carbon fiber wire in the tool is started to draw the carbon fiber wire to move along a straight line, and the moving speed is the same as the extending speed of the molten metal from the other end of the ceramic forming tube;

s6, cutting the carbon fiber wires after the molten spring steel extends out of the other end of the ceramic forming tube;

s7, unloading the formed spring blank with the carbon fiber mandrel clamped in the center from the workbench, resetting the traction mechanism of the carbon fiber wire, and then clamping the end part of the cut carbon fiber wire on the traction mechanism of the carbon fiber wire again to perform casting forming of the next spring blank;

and S8, rolling the outer part of the spring blank obtained in S7 into a spring blank with an oval cross section and an olive-shaped cross section along the axial direction by using a profiling roller.

In order to avoid retention of metal liquid flowing into the pipeline, smooth flowing of metal can be formed, and the preferred technical scheme is that the workbench is obliquely arranged, and the inclination angle is 15-30 degrees.

In order to facilitate the rapid shaping of the metal liquid flowing out of the ceramic forming pipe and avoid the retention of the metal liquid flowing into the pipeline, the metal can form smooth flow, and the spring blank cooling mechanism further preferably comprises a water spraying mechanism formed by sequentially connecting a water tank, a water pump, a water pipe and a spray head; the carbon fiber line tractor mechanism comprises a clamp, a nut connected with the clamp, a lead screw in threaded fit with the nut, and a driving motor connected with the lead screw, the clamp and the workbench are in sliding fit with a sliding rail through a sliding block, and the driving motor is installed on a rack of the workbench. The traction mechanism of the carbon fiber wire can keep the whole spring blank concentric with the ceramic forming pipe from head to tail, namely, the whole spring blank is positioned in the center of the spring cladding, and meanwhile, the traction mechanism can also play a role in drawing the blank which flows out of the ceramic forming pipe and is cooled, and the metal liquid moving forwards can be prevented from being detained in the inflow pipeline, so that the metal can form smooth flowing.

The invention has the advantages and beneficial effects that: the variable cross-section spring blank, the processing tool of the spring blank and the processing technology of the spring blank have the advantages of being simple in structure, capable of reducing the weight of the spring, improving the strength of the spring, prolonging the service life of the spring, capable of improving the corrosion resistance of the spring and enabling the spring blank to be easily processed. And the problem of premature damage of the spring caused by uneven hand at different parts of the spring is solved. The parts with larger stress, higher vibration frequency and large amplitude are strengthened, and the whole weight of the spring can be lightened.

Drawings

FIG. 1 is a schematic structural view of a variable cross-section spring according to the present invention;

FIG. 2 is a schematic axial sectional view of the spring of the present invention;

fig. 3 is a schematic top view of the carbon fiber mandrel spring blank machining tool provided with the carbon fiber mandrel at the center.

In the figure: 1. a carbon fiber mandrel; 2. a spring blank; 3. a ceramic forming tube; 4. a carbon fiber wire guide tube; 5. a pay-off reel; 6. a spring blank cooling mechanism; 7. a carbon fiber wire pulling mechanism; 8. a thread guide needle; 9. a molten metal pouring gate; 10. a work bench.

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in fig. 1 and 2, the invention relates to a variable cross-section spring blank 2, wherein the spring blank 2 is a spiral spring blank, the cross section of the spiral spring blank is oval, the cross section along the axial direction is olive-shaped, and a carbon fiber mandrel 1 embedded in the spring material is arranged along the center of the oval.

In order to improve the tensile strength of the spring and facilitate the forming of the spiral spring, the invention has the preferred embodiment that the carbon fiber mandrel 1 embedded in the spring blank can only be one carbon fiber wire or a plurality of carbon fiber wires, and the preferred technical scheme is 5-10.

In order to enable the spiral spring to have a high supporting effect and absorb the self vibration in the movement of the spring, the invention further preferably adopts the embodiment that the plurality of carbon fiber wires are in a twisting shape, and the number of twisting turns is 15-60 turns/m.

In order to be able to use the spring with the carbon fiber mandrel in heavy construction machinery, a further preferred embodiment of the invention provides that the material of the spring blank wrapped around the mandrel is spring steel.

As shown in fig. 3, in order to be able to simply and quickly embed a carbon fiber wire in the center of spring steel at low cost to form a blank for processing a coil spring, the invention also provides a variable cross-section spring blank forming tool, which comprises a ceramic forming tube 3 with one end provided with a conical opening from small to large, the cross section of the ceramic forming tube 3 is oval, a carbon fiber wire guide tube 4 coaxial with the ceramic forming tube 3 is arranged at a position, which is 30-50 mm away from the open end, of the large end of the conical opening of the ceramic forming tube 3, one open end of the carbon fiber wire guide tube 4 faces the large end of the conical opening of the ceramic forming tube 3, a pay-off reel 5 for the carbon fiber wire is arranged in front of the other open end of the carbon fiber wire guide tube 4, and the other end of the ceramic forming tube 3 is provided with a spring blank cooling mechanism 6 and a carbon fiber wire; the tool is also provided with a lead needle 8 which is used for leading out the carbon fiber wire from the pay-off reel 5, then penetrates through the carbon fiber wire guide tube 4 and the ceramic forming tube 3 and clamps the carbon fiber wire on the traction mechanism 7 of the carbon fiber wire.

In order to enable the carbon fiber mandrel 1 to be positioned at the central part of the spring leather, the spring steel must be melted into liquid, then the melted metal liquid is poured into the high-temperature resistant ceramic forming tube 3 with the carbon fiber wire prefabricated in the center through the pouring gate 9, the length of the ceramic forming tube is not too long, so that the metal liquid flowing into the pipeline is prevented from being retained, and smooth flowing cannot be formed.

In order to embed the carbon fiber wire in the center of the spring steel simply, quickly and at low cost to form a blank for processing the spiral spring 2, the invention also provides a processing technology of the spring blank with the variable cross section, which comprises the following processing steps:

s1, sequentially installing the pay-off reel 5 of the carbon fiber wire, the carbon fiber wire guide tube 4, the ceramic forming tube 3, the spring blank cooling mechanism 6 and the carbon fiber wire traction mechanism 7 on the workbench 10;

s2, fixing the end part of the carbon fiber wire at one end of a threading needle 8 in the tool, sequentially penetrating the carbon fiber wire guide tube 4 and the ceramic forming tube 3 by the other end of the threading needle 8, and then removing one end of the carbon fiber wire from one end of the threading needle 8 and clamping the end of the carbon fiber wire on a traction mechanism 7 of the carbon fiber wire;

s3, pouring a certain amount of molten spring steel (molten steel required for pouring a spring blank) into the ceramic forming tube 3 from the molten metal pouring gate 9 at the large end side of the conical opening of the ceramic forming tube 3 in the tool;

s4, when the molten metal extends out from the other end of the ceramic forming tube 3, starting the spring blank cooling mechanism 6 in the tool to rapidly cool the formed molten metal extending out of the ceramic forming tube 3;

s5, when the spring blank cooling mechanism 7 is started, the traction mechanism 7 of the carbon fiber wire in the tool is started to draw the carbon fiber wire to move along a straight line, and the moving speed is the same as the extending speed of the molten metal from the other end of the ceramic forming tube 3;

s6, cutting the carbon fiber wires after the molten spring steel extends out of the other end of the ceramic forming tube 3;

s7, unloading the formed spring blank with the carbon fiber mandrel 1 clamped in the center from the workbench 10, resetting the traction mechanism 7, and then clamping the end part of the cut carbon fiber wire on the traction mechanism 7 again to perform casting forming of the next spring blank;

In order to avoid the retention of the metal liquid flowing into the pipeline and facilitate the metal to form smooth flow, the preferred embodiment of the invention is that the worktable 10 is arranged obliquely, and the inclination angle is 15-30 degrees, and is preferably 18 degrees.

In order to facilitate the rapid shaping of the metal liquid flowing out of the ceramic forming pipe, avoid the retention of the metal liquid flowing into the pipeline and facilitate the smooth flowing of the metal, the spring blank cooling mechanism 6 further comprises a water spraying mechanism formed by sequentially connecting a water tank, a water pump, a water pipe and a spray head; the carbon fiber line tractor mechanism 7 comprises a clamp, a nut connected with the clamp, a lead screw in threaded fit with the nut, and a driving motor connected with the lead screw, the clamp is in sliding fit with the workbench through a sliding block and a sliding rail, and the driving motor is installed on a rack of the workbench. The traction mechanism 7 of the carbon fiber wire can keep the whole spring blank concentric with the ceramic forming pipe from head to tail, namely, the whole spring blank is positioned in the center of the spring cladding, and meanwhile, the traction mechanism can also play a role in drawing the blank which flows out of the ceramic forming pipe and is cooled, and moves forwards to avoid the retention of metal liquid flowing into the pipeline, so that the metal can form smooth flow.

After the variable cross-section spring blank is processed, the blank can be subjected to hot rolling or cold rolling or forging and pressing treatment again, then the spring blank is placed in a tip rolling machine to be forged, then the spring blank is heated in a medium-frequency heating furnace, then a hot coil spring machine is used for coil coiling, then the spring blank is quenched in a quenching furnace, quenched and cooled, then the spring blank is tempered in a tempering furnace, then the spring blank is pressed down for 1 time by a first hydraulic machine, then the section of the spring is ground flat, then shot blasting treatment and shot blasting are carried out, then flaw detection is carried out, then the spring blank is pressed down for 3 times by a second hydraulic machine, and finally a protective layer is sprayed.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A variable cross-section spring blank forming tool is characterized by comprising a ceramic forming pipe with a conical opening from small to large, wherein the cross section of the ceramic forming pipe is oval, a carbon fiber wire guide pipe coaxial with the ceramic forming pipe is arranged at a position, 30-50 mm away from the opening end, of the large end of the conical opening of the ceramic forming pipe, one opening end of the carbon fiber wire guide pipe faces the large end of the conical opening of the ceramic forming pipe, a carbon fiber wire pay-off reel is arranged in front of the other opening end of the carbon fiber wire guide pipe, and a spring blank cooling mechanism and a carbon fiber wire traction mechanism are arranged at the other end of the ceramic forming pipe; the tool is also provided with a lead needle which is used for leading out the carbon fiber wire from the pay-off reel, then penetrating through the carbon fiber wire guide tube and the ceramic forming tube and clamping the carbon fiber wire on the traction mechanism of the carbon fiber wire.

2. The forming tool for the variable cross-section spring blank according to claim 1, wherein a molten metal pouring gate is arranged on one side of the ceramic forming tube, which is positioned at the large end of the conical opening.

3. The forming tool for the spring blank with the variable cross section as claimed in claim 1, wherein the spring blank is a spiral spring blank, the cross section of the spiral spring blank is oval, the cross section of the spiral spring blank along the axial direction is olive-shaped, and a carbon fiber mandrel embedded in the spring material is arranged along the center of the oval.

4. The forming tool for the spring blank with the variable cross section according to claim 3, wherein the carbon fiber mandrel embedded in the spring blank is a carbon fiber wire or a plurality of carbon fiber wires.

5. The forming tool for the variable cross-section spring blank according to claim 4, wherein the carbon fiber wires are twisted, and the number of the twisting turns is 15-60 turns/m.

6. The variable cross-section spring blank forming tool according to claim 5, wherein the material of the spring blank wrapped outside the mandrel is spring steel.

7. The processing technology of the spring blank with the variable cross section is characterized by comprising the following processing steps:

s1, sequentially installing a pay-off reel of the carbon fiber wire, a carbon fiber wire guide tube, a ceramic forming tube, a spring blank cooling mechanism and a carbon fiber wire traction mechanism in the tool of claim 1 on a workbench;

s2, fixing the end part of the carbon fiber wire at one end of a threading needle in the tool of claim 1, sequentially penetrating a carbon fiber wire guide tube and a ceramic forming tube by the other end of the threading needle, and then removing one end of the carbon fiber wire from one end of the threading needle to clamp the carbon fiber wire on a traction mechanism of the carbon fiber wire;

s3, pouring a certain amount of molten spring steel into the ceramic forming tube from a molten metal pouring gate at the large end side of the conical opening of the ceramic forming tube in the tool of claim 1;

s4, when the molten metal extends out from the other end of the ceramic forming tube, starting a spring blank cooling mechanism in the tool of claim 1 to rapidly cool the formed molten metal extending out of the ceramic forming tube;

s5, when the spring blank cooling mechanism is started, the carbon fiber wire drawing mechanism in the tool of claim 1 is started to draw the carbon fiber wire to move linearly at the same speed as the extending speed of the molten metal from the other end of the ceramic forming tube;

8. The process for machining a spring blank with a variable cross section according to claim 7, wherein the worktable is arranged obliquely, and the inclination angle is 15-30 degrees.

9. The process for machining a spring blank with a variable cross section according to claim 8, wherein the spring blank cooling mechanism comprises a water spraying mechanism formed by sequentially connecting a water tank, a water pump, a water pipe and a spray head; the carbon fiber line tractor mechanism comprises a clamp, a nut connected with the clamp, a lead screw in threaded fit with the nut, and a driving motor connected with the lead screw, the clamp and the workbench are in sliding fit with a sliding rail through a sliding block, and the driving motor is installed on a rack of the workbench.