Inner-cooling brazed grinding wheel capable of efficiently transporting cutting fluid and operation method of inner-cooling brazed grinding wheel

Abstract

The invention relates to an inner-cooling brazed grinding wheel capable of efficiently transporting cutting fluid and an operation method of the inner-cooling brazed grinding wheel. The grinding wheel comprises a metal matrix, a brazed abrasive layer and an inner-cooling runner system. The metal base body is divided into an upper base body and a lower base body, the brazing abrasive material layer is brazed to the peripheral face of the metal base body, the inner cooling runner system is integrated in the metal base body and composed of an annular runner and radial runners, the annular runner surrounds the center of the grinding wheel, and the radial runners evenly extend from the annular runner to the edge of the grinding wheel. The radial flow channels are arranged to be of a double-U-shaped structure and an arc-shaped structure respectively, and a micro-groove backflow prevention structure is arranged in the arc-shaped structure flow channel. In the working process, cooling liquid is introduced into the inner cooling flow channel system by means of the rotating shaft of the upper base body, the cooling liquid is distributed to the radial flow channel through the annular flow channel and then conveyed to the position near a grinding wheel grinding area, and accurate and efficient cooling of the grinding area is achieved through orderly guiding of the cooling liquid. Through the backflow prevention and multi-stage flow distribution structure, the supply uniformity and the cooling efficiency are improved, and the device is suitable for high-speed grinding machining scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical manufacturing grinding processing, in particular to an inner-cooling brazed grinding wheel with high-efficiency cutting fluid conveying, and a processing and operating method thereof. TECHNICAL BACKGROUND

[0002] In the grinding process, brazed grinding wheels are widely used due to their high bonding strength and good abrasive holding force. However, a large amount of heat is generated during grinding, which can easily cause surface burns of the workpiece and accelerated wear of the grinding wheel if not cooled in time and effectively. The traditional pouring cooling method relies on gravity or low-pressure pumping, and the cooling liquid is difficult to break through the grinding arc area air barrier, so it cannot take away the cutting chips in time and can only cover about 30% of the effective area of the grinding wheel surface, resulting in grinding burns, micro-cracks and residual tensile stress on the surface layer of the workpiece, which seriously affects the fatigue strength of the part. In addition, the high-temperature environment can accelerate the wear of the abrasive and the softening of the binder, causing the abrasive to fall off or become blunt prematurely. Relevant test data shows that under the condition of pouring cooling, the average service life of the brazed CBN grinding wheel is only 30-50 minutes, and the grinding ratio (material removal volume / grinding wheel wear volume) is less than 200, which requires frequent dressing or replacement, increasing downtime and cost. Therefore, it is crucial to design a high-performance inner-cooling brazed grinding wheel to achieve precise and efficient cooling of the grinding area, which is essential to improve the grinding quality and service life of the grinding wheel.

[0003] The patent application file with the application number CN213319666.U discloses an inner-cooling grinding wheel, which includes a grinding wheel and a cooling box fixedly connected with the grinding wheel. The grinding wheel internally includes a plurality of cooling cavities connected with the cooling box through first connecting pipes. The inner-cooling grinding wheel can cool the interior of the grinding wheel through the cooling cavities and the cooling liquid, so that the grinding wheel can be kept at a certain temperature for grinding. However, the grinding wheel does not precisely convey the cooling liquid to the grinding area, and the cooling and lubricating effect on the grinding arc area is not good. At the same time, the existing flow channel design is also likely to cause the cooling liquid to flow back, reducing the grinding efficiency.

[0004] The patent application file with the application number CN110480506.B discloses an inner-cooling grooved grinding wheel device for form grinding, which includes a spindle and a grinding wheel assembly. The upper base and the lower base of the grinding wheel are connected by bolts, and the two are internally provided with grooves for placing cooling liquid passages. The bifurcated channels are a plurality of arc-shaped bifurcated grooves uniformly arranged around the shaft center, and the inlet thereof is communicated with the liquid storage cavity. This design makes the radial flow channel too long. According to fluid dynamics, this will greatly increase the along-path resistance of the fluid, and because there is only one layer of annular flow channel, the uniformity of the fluid distribution in it will be poor, affecting the cooling efficiency.

[0005] The patent application file with the application number CN222059963.U discloses an internal cooling type grinding wheel, the grinding wheel has an internal cooling system for reducing the temperature of the grinding wheel and the workpiece, improving the cutting efficiency and tool life, and the heat-conducting sheet arranged on the surface of the dial can help the cooling liquid to more effectively absorb and disperse heat. But from the structural design drawing paper, it is found that the internal cavity of the grinding wheel is too large, which affects the strength of the grinding wheel, and may also cause the internal liquid to fail to reach dynamic balance when the grinding wheel rotates, greatly affecting the stability of processing. SUMMARY

[0006] The present application is designed to solve the problems of the prior art, and provides an internal cooling brazed grinding wheel with efficient cutting fluid transportation and an operation method thereof, which can solve the problem of difficult heat dissipation in grinding processing, improve the processing quality, and improve the cooling efficiency to achieve precise and efficient cooling of the grinding area.

[0007] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0008] An internal cooling brazed grinding wheel with efficient cutting fluid transportation, comprising a metal base, a brazed abrasive layer, and an internal cooling flow channel system; the metal base is composed of an upper base and a lower base and is assembled by bolts; the upper base is provided with a hollow rotating shaft; the upper and lower bases are provided with grooves on the circumferential side surfaces to achieve intermittent grinding; the groove side surfaces are provided with flow channel outlets so that the cooling liquid can be accurately supplied to the grinding area after flowing out along the arc-shaped flow channel; and the brazed abrasive layer is welded to the outer circumferential side surface of the metal base by a high-frequency induction brazing method.

[0009] The internal cooling flow channel system is located inside the metal base and is formed after the corresponding semicircular groove parts of the upper base and the lower base are assembled; the internal cooling flow channel system comprises an annular flow channel arranged around the center of the grinding wheel and a radial flow channel extending from the annular flow channel to the edge of the grinding wheel. The annular flow channel of the internal cooling flow channel system is provided with two levels, which are a first annular flow channel and a second annular flow channel arranged from near to far according to the distance from the center of the base, and a backflow prevention structure is arranged between the first annular flow channel and the second annular flow channel, which is a double-U-shaped flow channel. When the grinding wheel rotates and a certain flow channel is placed above the grinding wheel, the cutting fluid will not flow back due to gravity because of the double-U-shaped structure of the flow channel, ensuring normal liquid circulation and good backflow prevention effect; at the same time, it has an important influence on the stable transportation of the cutting fluid inside the grinding wheel; the radial flow channel comprises an arc-shaped radial flow channel and a curved line radial flow channel, wherein the arc-shaped radial flow channel is located between the second annular flow channel and the edge of the grinding wheel.

[0010] The flow channel section of the inner cooling flow channel system is circular, and the diameter size ranges from 2 to 10 mm. The purpose of selecting a circular flow channel is that the hydraulic radius of the circular section is the largest, and the contact area of the fluid with the flow channel wall is relatively the smallest. This can significantly reduce the resistance and local resistance along the way, make the liquid flow more smoothly, and reduce the energy loss in the conveying process. The specific size can be selected according to the required cooling liquid flow and flow rate in the grinding process.

[0011] The curved radial flow channel of the inner cooling flow channel system is distributed along the circumference of the grinding wheel, and the number is more than one. In embodiment 1 of the present application, a double "U" shaped bend structure is adopted. When the grinding wheel rotates and a certain flow channel is placed above the grinding wheel, because of the curved structure of the flow channel, the cutting fluid will not flow back due to gravity, so that the structure design of the grinding wheel can ensure that the liquid flows normally under the condition of better non-return effect. At the same time, it has an important influence on the stable transportation of the cutting fluid in the grinding wheel.

[0012] The arc of the arc radial flow channel of the inner cooling flow channel system is formed by fitting multiple line segments when designing, and the arc is along the tangent direction of the outer circle of the grinding wheel, and the number is more than one. In embodiment 1, the number is 16. The curve equation of the arc flow channel is as follows:

[0013] ;

[0014] ;

[0015] is the distance of a certain point on the arc from the origin, and θ is the included angle between the point position and the original position, represents each point, and α is the included angle between the liquid flow velocity direction at the outlet and the linear velocity direction of the grinding wheel, Assume that is the radius size at two adjacent inflection points on the arc. The size of α affects the cooling effect of the cooling liquid on the grinding area of the grinding wheel. The smaller the size, the more the cooling liquid is sprayed to the grinding wheel surface. However, from the formula, it can be seen that the size of α affects the distance between the two inflection points on the arc. The smaller the size, the more difficult the design and preparation. Therefore, the general size can be selected as 25° to 35°.

[0016] The inner surface of the arc radial flow channel adopts micron level rectangular grooves, and the depth can be set to 50 to 100 μm. Such depth can make water produce significant capillary rise effect in the groove, and enhance the stability of forward flow. The corners of the rectangular groove can enhance the curvature mutation of the liquid surface when flowing in the opposite direction, and improve the non-return effect. The distance between the grooves needs to be less than the capillary characteristic length of the liquid (usually 100 to 500 μm) to form a continuous micro network, so as to avoid the liquid flowing in the opposite direction around the groove; the groove arrangement can be parallel array arrangement or staggered arrangement. Through the action of micro structure, the backflow of cutting fluid can be reduced.

[0017] The annular flow channel of the inner cooling channel system is provided with two stages, so that the liquid can be more evenly distributed inside when the grinding wheel transports the cooling liquid, and the stability of the grinding wheel during use is increased. The inner annular flow channel is designed in two stages and is connected with the radial flow channel to form an inner flow channel network. The use of a stepped annular flow channel first reduces the length of the radial flow channel, thereby effectively reducing the resistance loss along the way when transporting the cooling liquid; secondly, the use of a two-stage annular flow channel allows the cooling liquid to be evenly redistributed in the two-stage annular flow channel, increasing the uniformity and stability of the transport; and because of the centrifugal force caused by the rotation of the grinding wheel, the cooling liquid in the two-stage annular flow channel can cooperate with the arc design of the two-stage radial flow channel to increase the flow rate of the transported cooling liquid, and the increase in flow rate is beneficial to the flushing of the grinding dust by the cooling liquid.

[0018] The abrasive grains of the brazing abrasive layer are divided into a plurality of abrasive grain groups, the abrasive grain groups are orderly arranged, the interval is 1-1.5 mm, the abrasive grains in each abrasive grain group are also orderly arranged, the interval is 100-300 μm, the particle size range is 60-120, the abrasive grains are diamond or CBN abrasive, and the shear strength of the bonding surface between the abrasive grains and the binder is not less than 50 MPa. The brazing abrasive layer is firmly brazed to the outer peripheral surface of the base, and the abrasive layer is sequentially provided with a binder transition layer (containing 30% by volume of abrasive grains) and a cutting working layer (containing 60%-70% by volume of abrasive grains) outward from the base. Through composition gradient optimization, the interface bonding strength and abrasive wear uniformity are improved.

[0019] An operating method of an inner cooling brazing grinding wheel for efficient transportation of cutting fluid, comprising the following steps:

[0020] (1) precisely connect the grinding wheel with the inner cooling spindle of the grinding equipment through the liquid inlet end of the rotating shaft of the upper base; start the equipment for idling debugging and detect the dynamic balance of the grinding wheel.

[0021] (2) start the cooling liquid supply system, adjust the cooling liquid flow and pressure, and then the cooling liquid enters the liquid delivery shaft through the inner cooling spindle, and then sequentially flows through the first annular flow channel and the first radial flow channel of the inner cooling channel system. The cooling liquid enters the second annular flow channel from the first radial flow channel, and during this process, due to the special curved structure of the radial flow channel, when a part of the pipeline is located on the upper part of the grinding wheel due to rotation, this structure can prevent the cooling liquid from flowing back due to gravity. Then the cooling liquid enters the second radial flow channel from the second annular flow channel, and the wall surface in the second radial flow channel is designed with a microstructure to prevent backflow, which also has an inhibitory effect on the backflow of the cooling liquid. The cooling liquid passes through these efficient transportation flow channel structures and finally reaches the groove on the circumferential side surface of the grinding wheel base.

[0022] (3) Since the peripheral radial flow channel is designed based on the circular tangent principle, the cooling liquid can accurately reach the grinding arc area from the groove outlet, and the cutting fluid reaching the grinding arc area enters the grinding area through the gap between the abrasive particle groups and the gap between the abrasive particles, and finally realizes uniform and efficient cooling and lubrication.

[0023] Advantages

[0024] (1) The efficiency of transporting cooling liquid is improved: due to the unique anti-backflow structure inside the inner cooling grinding wheel, the "U" shaped bending structure designed by the first level radial flow channel using the internal pressure difference of the liquid and the micro anti-backflow structure of the wall surface of the second level radial flow channel, so that part of the cooling liquid in the inner flow channel of the grinding wheel which is not in the grinding arc area will not backflow due to gravity, compared with the traditional external cooling method, the cooling efficiency is improved. The peripheral radial flow channel is designed based on the circular tangent principle, so that the cooling liquid can accurately reach the grinding surface. The inner cooling flow channel system which efficiently transports cutting fluid realizes accurate and efficient cooling of the grinding area by the cooling liquid, effectively avoids defects such as workpiece surface burning and cracking, and improves the grinding surface quality.

[0025] (2) The service life of the grinding wheel is prolonged: the accurate supply of cooling liquid to the grinding arc area can effectively reduce the grinding temperature; the reasonable and orderly arrangement of abrasive particles makes the cooling liquid fully enter the gap between the abrasive particles in the grinding arc area, and timely cooling reduces the working temperature of the grinding wheel, reduces the problems such as failure of abrasives due to high temperature and softening of binder, and at the same time, abrasive particles with high shear strength are selected, so that the service life of the grinding wheel is prolonged compared with the conventional brazing grinding wheel, and the grinding wheel replacement frequency and processing cost are reduced.

[0026] (3) The processing efficiency is improved: the cooperation of the radial and annular flow channels inside the grinding wheel increases the uniformity and stability of the cooling liquid transportation, and the stable cooling environment guarantees the stability of the grinding process, which can appropriately improve the grinding process parameters (such as increasing the grinding depth and improving the feed speed), under the premise of ensuring the processing quality, the processing efficiency is improved, which is suitable for batch and efficient grinding processing scenes. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the whole structure of the inner cooling brazing grinding wheel of the application for efficiently transporting cutting fluid;

[0028] Figure 2 is a schematic diagram of the lower base 2 structure of the grinding wheel;

[0029] Figure 3 is a schematic diagram of the upper base 3 structure of the grinding wheel;

[0030] Figure 4 is a schematic diagram of the circular tangent principle of the arc-shaped flow channel;

[0031] Figure 5 is a schematic diagram of the ordered arrangement of abrasive particles;

[0032] Figure 6 is a schematic diagram of the pipe wall anti-backflow microstructure;

[0033] Figure 7 is a vector diagram of the flow rate of the grinding wheel flow channel coolant simulated by fluent.

[0034] Detailed description of the marks in the drawings: screw-1; grinding wheel lower base-2; grinding wheel upper base-3; bolt-4; rotating shaft-5; liquid outlet-6; arc-shaped radial flow channel I-7-1, arc-shaped radial flow channel II-7-2; curved line radial flow channel I-10-1, curved line radial flow channel II-10-2; first-order annular flow channel I-11-1, first-order annular cavity II-11-2; second-order annular flow channel I-12-1, second-order annular flow channel II-12-2; brazing abrasive layer I-13-1, brazing abrasive layer II-13-2. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be specifically described below in combination with examples and drawings.

[0036] Example 1

[0037] Figure 1 is a schematic diagram of the overall structure of the high-efficiency transport cutting fluid inner-cooled brazing grinding wheel of the present application, Figure 2 is a schematic diagram of the structure of the grinding wheel lower base 2, Figure 3 is a schematic diagram of the structure of the grinding wheel upper base 3.

[0038] Referring to Figures 1 to 3 , a high-efficiency transport cutting fluid inner-cooled brazing grinding wheel includes a metal base, a brazing abrasive layer, and an inner-cooled flow channel system. The metal base includes a grinding wheel upper base 3 and a grinding wheel lower base 2, which are assembled by bolts 4. The upper base 3 is provided with a hollow rotating shaft 5 for connecting with the inner-cooled main shaft (such as a hydraulic tool holder) of the grinding equipment, and an inlet 14 is provided on the upper base 3 for the input of coolant. The upper and lower base circumferential sides are provided with grooves, and the groove sides are provided with liquid outlets 6. The brazing abrasive layer is welded to the outer peripheral side of the metal base by high-frequency induction brazing method.

[0039] The inner cooling channel system is located inside the metal base and formed by corresponding groove parts of the upper base and the lower base after assembly, which includes an annular channel arranged around the center of the grinding wheel and radial channels extending from the annular channel to the edge of the grinding wheel. The annular channel can be divided into a first annular channel and a second annular channel from the center of the base to the outside, and a backflow prevention structure is arranged between the first annular channel and the second annular channel, which is a double U-shaped channel. When the grinding wheel rotates and a certain channel is placed above the grinding wheel, the cutting fluid will not flow back due to the curved structure of the channel, ensuring that the liquid flows normally and having a good backflow prevention effect. At the same time, it has an important influence on the stable transportation of the cutting fluid inside the grinding wheel. The cooling liquid enters the second annular channel through the first annular channel, and finally is supplied to the brazing abrasive layer through the liquid outlet 6.

[0040] The radial channel is divided into an arc-shaped radial channel and a curved line radial channel. The arc-shaped radial channel is located between the second annular channel and the edge of the grinding wheel, which can be called an "outer radial arc-shaped channel", and a micro-groove backflow prevention structure is arranged inside. The curved line radial channel is a double U-shaped structure.

[0041] As shown in Figure 4 , in the outer radial arc-shaped channel, the arc line is along the tangent direction of the outer circle of the grinding wheel, and the distance between a certain point on the arc line and the origin is , and the included angle θ between the point position and the original position satisfies the following formula:

[0042] (1)

[0043] (2)

[0044] Formula (1) is the curve equation of the arc line channel; represents each point, and α is the included angle between the liquid flow velocity direction at the outlet and the linear velocity direction of the grinding wheel, Assuming that R is the radius size at two adjacent inflection points on the arc line (as shown in Figure 4 ). The size of α affects the cooling effect of the cooling liquid on the grinding area of the grinding wheel, and the smaller the cooling liquid is ejected, the more the grinding wheel surface is fitted. However, it can be seen from the formula that the size of α affects the distance between the two inflection points on the arc line, and the smaller the size is, the more difficult the preparation is. Therefore, 25°~35° is selected.

[0045] At the same time, in the outer radial arc-shaped channel, that is, in the arc-shaped radial channel I and the arc-shaped radial channel II, in order to enhance the backflow prevention characteristics of the grinding wheel, a micro backflow prevention structure is arranged in this part of the channel during processing, as shown in Figure 6The trenches shown are set to a depth of 50-100 μm. This depth allows for a significant capillary uplift effect within the trenches, enhancing the stability of forward flow. The trench shape can be rectangular; the sharp corners of the rectangular trenches enhance the abrupt change in liquid surface curvature during reverse flow, improving the check valve effect. The trench spacing must be less than the capillary characteristic length of the liquid (typically 100-500 μm) to form a continuous micro-network, preventing liquid from bypassing the trenches and flowing backward. Multiple rows and columns of trenches can be arranged, either in parallel arrays or staggered arrangements.

[0046] In summary, the internal annular flow channel of the grinding wheel is designed in two stages, intersecting and connecting with the radial flow channel to form an internal flow channel network. The use of a staged annular flow channel firstly reduces the length of the radial flow channel, thus effectively reducing friction loss during coolant transport; secondly, the use of a two-stage annular flow channel allows for a more uniform redistribution of the coolant within the two stages, increasing the uniformity and stability of transport; and thirdly, due to the centrifugal force generated by the grinding wheel's rotation, the coolant within the two-stage annular flow channel, combined with the arc design of the two-stage radial flow channel, allows the transported coolant to experience increased flow velocity due to centrifugal force, which is beneficial for the coolant to flush away grinding debris.

[0047] The brazed abrasive layer is firmly brazed to the outer peripheral surface of the substrate, such as brazed abrasive layer I13-1 and brazed abrasive layer II13-2. The abrasive grains are arranged in an orderly manner, such as... Figure 5 The arrangement shown has an abrasive grain spacing of 1~1.5mm between abrasive grain clusters, and an abrasive grain spacing of 100~300μm within each abrasive grain zone, with a grain size range of 60#~120#. The orderly arrangement of abrasive grains allows for better flow of coolant between the abrasive grains, further improving the cooling characteristics of the grinding wheel while achieving the grinding function. The upper and lower bases are connected by screws 1 and bolts 4.

[0048] The preparation process of the aforementioned internally cooled brazed grinding wheel with high-efficiency cutting fluid transport is as follows:

[0049] (1) Matrix processing: High-strength alloy steel is used to manufacture upper and lower matrix with a preset internal cooling channel system through casting, forging and machining processes. The machining accuracy of the channel groove of the internal cooling channel system is controlled within ±0.05mm to ensure the sealing of the channel and the stability of the coolant flow.

[0050] (2) Preparation of brazed abrasive layer: Select suitable abrasive (such as diamond, CBN, etc., determined according to the material of the workpiece being ground) and brazing filler metal, distribute the abrasive evenly in the brazing filler metal, and use vacuum brazing process to braze the outer peripheral surface of the substrate to form a brazed abrasive layer. Strictly control the brazing temperature and time to ensure the bonding strength and grinding performance of the abrasive layer.

[0051] (3) Overall assembly: after the upper and lower bases are connected by screws and bolts, the overall assembly is carried out on the corresponding machine tool spindle with an internal cooling system through the rotation shaft of the upper base and other auxiliary components (such as an external-to-internal cooling joint or a hydraulic tool holder), overall dynamic balance test and correction are carried out to ensure the stability of the grinding wheel during use.

[0052] (4) Cooling liquid selection: according to the material of the ground workpiece and the processing requirements, appropriate cooling liquid is selected, such as water-soluble cutting fluid for grinding metal workpieces, which has good cooling, lubrication and rust prevention performance; special cutting fluid can be selected for grinding hard alloy and other difficult-to-machine materials. The cooling liquid needs to be filtered and replaced regularly to keep it clean and avoid impurities blocking the internal cooling flow channel.

[0053] (5) Process parameter matching: for different workpieces (such as steel, aluminum alloy, hard alloy, etc.), the best grinding process parameters and cooling liquid supply parameters are determined through tests to ensure the collaborative optimization of grinding quality and cooling effect.

[0054] (6) Maintenance and repair: regularly maintain the grinding wheel, clean the impurities at the inlet of the internal cooling flow channel, check the sealing performance of the flow channel, and repair or replace the sealing components in time if leakage is found. When the abrasive layer of the grinding wheel is worn to 1 / 3, the grinding wheel needs to be repaired or replaced, and attention should be paid to protecting the internal cooling flow channel structure during the repair process to ensure normal use later.

[0055] The operation method of the above-mentioned high-efficiency cutting fluid conveying internal cooling brazed grinding wheel is as follows:

[0056] (1) The grinding wheel is precisely connected with the internal cooling spindle of the grinding equipment through the liquid inlet end of the rotation shaft 5 of the upper base; the equipment is started and idled for debugging, and the dynamic balance of the grinding wheel is detected.

[0057] (2) Start the cooling liquid supply system, adjust the cooling liquid flow and pressure, and the cooling liquid enters the liquid conveying shaft through the internal cooling spindle, then flows through the first-stage annular flow channel (first-stage annular flow channel I 11-1, first-stage annular flow channel II 11-2) and the first-stage radial flow channel (curved radial flow channel I 10-1, curved radial flow channel II 10-2) of the internal cooling flow channel system in sequence. The cooling liquid enters the second-stage annular flow channel (second-stage annular flow channel I 12-1, second-stage annular flow channel II 12-2) from the first-stage radial flow channel, and in this process, due to the special curved structure of the radial flow channel, when part of the pipeline is placed on the upper part of the grinding wheel due to rotation, this structure can prevent the cooling liquid from flowing back due to gravity. Then the cooling liquid enters the second-stage radial flow channel (arc-shaped radial flow channel I 7-1, arc-shaped radial flow channel II 7-2) from the second-stage annular flow channel, and the wall surface inside the second-stage radial flow channel is designed with a microstructure to prevent backflow, which also has an inhibitory effect on the backflow of the cooling liquid. The cooling liquid passes through these high-efficiency conveying flow channel structures and finally reaches the groove on the circumferential side surface of the grinding wheel base.

[0058] (3) Since the peripheral radial flow channels (arc-shaped radial flow channel I 7-1, arc-shaped radial flow channel II 7-2) are designed based on the principle of a circular tangent, the cooling liquid that comes out of the groove at the liquid outlet 6 can accurately reach the grinding arc area, and the cutting fluid that reaches the grinding arc area enters the grinding area through the gaps between the abrasive particle groups and the gaps between the abrasive particles, ultimately achieving uniform and efficient cooling and lubrication, as shown in FIG. 8. Figure 7

[0059] The embodiments are not intended to limit the shape, material, structure, etc. of the present application in any form, and any simple modification, equivalent change, and modification of the above embodiments according to the technical essence of the present application are within the protection scope of the technical solution of the present application.​

Claims

1. A high efficiency transport cutting fluid, inner-cooled brazed grinding wheel, characterized in that, The application relates to a metal base, a brazing abrasive layer and an inner cooling channel system, wherein the metal base comprises an upper base and a lower base which are assembled by bolts; the upper base is provided with a hollow rotating shaft which is used for being connected with an inner cooling main shaft of a grinding equipment; the upper and lower bases are provided with grooves on the circumferential sides, and the groove sides are provided with liquid outlets; the brazing abrasive layer is welded on the circumferential sides of the metal base by a high-frequency induction brazing method. The inner cooling channel system is located in the metal base and is formed after the corresponding groove parts of the upper base and the lower base are assembled, and the inner cooling channel system comprises an annular channel which is arranged around the center of the grinding wheel and radial channels which extend from the annular channel to the edge of the grinding wheel.

2. The internally cooled brazed grinding wheel for efficient delivery of cutting fluid according to claim 1, wherein, The annular channel of the inner cooling channel system is provided with two stages, and the annular channel is provided with a first-stage annular channel and a second-stage annular channel from the center of the base to the edge of the base; a backflow prevention structure is arranged between the first-stage annular channel and the second-stage annular channel, and the backflow prevention structure is a double-U-shaped channel; when the grinding wheel rotates and the channel is located above the grinding wheel, the cutting fluid cannot flow back due to the double-U-shaped structure of the channel, so that the backflow prevention effect is good under the condition that the cutting fluid normally flows; meanwhile, the backflow prevention structure has an important influence on the stable transportation of the cutting fluid in the grinding wheel. The radial channels comprise arc-shaped radial channels and curved-line radial channels, and the arc-shaped radial channels are located between the second-stage annular channel and the edge of the grinding wheel.

3. The internally-cooled brazed grinding wheel for efficient transport of cutting fluid of claim 1, wherein, The cross sections of the channels of the inner cooling channel system are circular, the diameter ranges from 2mm to 10mm, and the diameter can be selected according to the required cooling liquid flow and flow speed in the grinding process.

4. The internally-cooled brazed grinding wheel for efficient delivery of a cutting fluid of claim 2, wherein, The curved-line radial channels are double-U-shaped structures and are uniformly distributed along the circumference of the grinding wheel and are more than one in number.

5. The internally-cooled brazed grinding wheel for efficient transport of cutting fluid of claim 1, wherein, The arc lines of the arc-shaped radial channels are formed by fitting a plurality of line segments, the arc lines are arranged along the tangential direction of the outer circle of the grinding wheel, and the arc lines are more than one in number; the inner surfaces of the channels are provided with micron-level rectangular grooves to reduce the backflow of the cutting fluid. The curve equation of the arc line channel is: ； ； is the distance of a point on the arc from the origin, and θ is the angle between the point and the origin, represents each point, and α is the angle between the liquid flow direction at the outlet and the direction of the grinding wheel linear velocity, which is 25°-35°; Assuming that is the radius size at two adjacent inflection points on the arc.

6. The internally-cooled brazed grinding wheel for efficient delivery of a cutting fluid of claim 1, wherein, The depth of the micron-level rectangular groove is 50-100mu. The groove spacing is less than the capillary characteristic length of the liquid, so that a continuous micro network is formed to avoid the reverse flow of the liquid bypassing the groove. The groove arrangement is selected to be parallel array arrangement or staggered arrangement.

7. The internally-cooled brazed grinding wheel for efficient transport of cutting fluid of claim 1, wherein, The abrasive grains of the brazing abrasive layer are divided into a plurality of abrasive grain groups, the abrasive grain groups are orderly arranged, the spacing is 1-1.5mm, the abrasive grains of each abrasive grain group are also orderly arranged, the spacing is 100-300mu, the grain size ranges from 60# to 120#, the abrasive grains are diamond or CBN abrasive grains, and the shear strength of the bonding surface between the abrasive grains and the binder is not less than 50MPa.

8. The method of claim 1, wherein the high efficiency internally cooled brazed grinding wheel is used for transporting the cutting fluid. The steps are as follows: ​ (1) base processing: high-strength alloy steel is adopted, casting, forging and mechanical processing technology are combined, the upper and lower bases with a preset inner cooling channel system are manufactured, the processing precision of the channel grooves of the inner cooling channel system is controlled within 0.05mm, and the subsequent flow channel sealing performance and the cooling liquid flow stability are guaranteed; (2) brazing abrasive layer preparation: suitable abrasive grains and filler metals are selected, the abrasive grains are uniformly distributed in the filler metals, a vacuum brazing process is adopted, the brazing abrasive layer is brazed on the outer circumferential surface of the base, and the brazing temperature and time are strictly controlled to ensure the bonding strength and the grinding performance of the abrasive layer. The abrasive material includes diamond, CBN, and is determined according to the material of the ground workpiece; (3) Overall assembly: after the upper and lower bases are connected by screws and bolts, the rotating shaft of the upper base is assembled with the outer rotating inner cooling joint or hydraulic tool holder on the corresponding machine tool spindle with an internal cooling system for overall dynamic balance test and correction to ensure the stability of the grinding wheel during use; (4) Selection of cooling liquid: select appropriate cooling liquid according to the material of the ground workpiece and the processing requirements; (5) Process parameter matching: for different workpieces (such as steel, aluminum alloy, hard alloy, etc.), the best grinding process parameters and cooling liquid supply parameters are determined through tests to ensure the synergistic optimization of grinding quality and cooling effect; (6) Maintenance and repair: regularly maintain the grinding wheel, clean the impurities at the inlet of the internal cooling flow channel, check the sealing performance of the flow channel, and if leakage is found, repair or replace the sealing parts in time. When the abrasive layer of the grinding wheel is worn to 1 / 3, the grinding wheel is repaired or replaced, and attention is paid to protecting the internal cooling flow channel structure during the repair process to ensure normal use later.

9. The method of claim 8, wherein the method further comprises the step of: In step (4), the selection rules of the cooling liquid are as follows: when grinding metal workpieces, water-soluble cutting fluid is used, which has good cooling, lubrication and rust prevention performance; when grinding difficult-to-machine materials including hard alloy, special cutting fluid is selected; the cooling liquid needs to be filtered and replaced regularly to keep it clean and avoid impurities blocking the internal cooling flow channel. ​ 10. The method of operating a high efficiency internally cooled brazed grinding wheel for delivering a cutting fluid as defined in claim 1, wherein, The steps are as follows: (1) The grinding wheel is precisely connected with the internal cooling spindle of the grinding equipment through the liquid inlet of the rotating shaft 5 of the upper base; start the equipment for idling debugging and detect the dynamic balance of the grinding wheel; (2) Start the cooling liquid supply system, adjust the cooling liquid flow and pressure, and the cooling liquid enters the liquid delivery shaft through the internal cooling spindle, and then flows through the first annular flow channel and the first radial flow channel of the internal cooling flow channel system in turn; the cooling liquid enters the second annular flow channel from the first radial flow channel, and due to the curved structure of the first radial flow channel, when part of the pipeline is placed on the upper part of the grinding wheel due to rotation, this structure can prevent the cooling liquid from flowing back due to gravity; Then the cooling liquid enters the second radial flow channel from the second annular flow channel, and a microstructure is designed on the inner wall of the second radial flow channel to prevent backflow of the cooling liquid; The cooling liquid passes through these efficient flow channel structures and finally reaches the liquid outlet of the groove on the circumferential side of the grinding wheel base; (3) Since the second radial flow channel is designed based on the principle of circular tangent, the cooling liquid precisely reaches the grinding arc area after coming out of the liquid outlet 6 of the groove, and the cutting fluid reaching the grinding arc area enters the grinding area through the gaps between the abrasive particle groups and the gaps between the abrasive particles, and finally realizes uniform and efficient cooling and lubrication.

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