CN114932253A - A tool with internal cooling jet structure - Google Patents

Abstract

The invention provides a tool with an internal cooling jet structure, which relates to the field of cutting tools and includes a drill bit. A helical cooling channel is arranged in the drill bit, and one end of the cooling channel extends to the drill tip as an outlet; the cooling channel passes through the side surface of the drill bit. The preset jet holes are connected to the outside, and the cooling channel close to the outlet is provided with a constriction portion, and the radial cross-sectional area of the constriction portion is smaller than that of other areas of the cooling channel, so that the cooling liquid is atomized at the outlet position; for the current drill bit The problem of poor cooling effect during tool processing. The cooling liquid is transported through the cooling channel, and the cooling liquid is sprayed from the outlet at the drill tip and the side jet holes. The output of the outlet is dispersed and atomized. The cooling liquid can cool and lubricate the cutting position. The coolant jet from the jet hole can flush the chips out of the groove of the drill bit, so as to meet the cooling and lubrication requirements.

Description

A tool with internal cooling jet structure

technical field

The invention relates to the field of cutting tools, in particular to a tool with an internal cooling jet structure.

Background technique

In order to reduce the adverse effect of excessive cutting temperature on the machining process and tool life, the tool is usually cooled and lubricated with a cooling medium. For the traditional casting cutting fluid cooling method, the main problems include low coolant pressure and poor penetration ability, it is difficult to enter the cutting area for effective cooling, and as the cutting speed increases, the cooling effect is significantly reduced, and the cutting efficiency is limited. Therefore, the development of a new type of cooling structure tool to enhance the heat transfer efficiency of the coolant in the cutting area is of great significance for improving the cutting performance of the tool, prolonging the tool life and ensuring the machining quality, especially for titanium alloys, superalloys, high-strength steels, and vermicular ink. Efficient machining of parts in difficult-to-machine materials such as cast iron is particularly important.

The application of the internal cooling drill bit alleviates the above problems to a certain extent. The feature of the internal cooling drill is that it has a cooling hole that runs through the shank of the drill bit to the drill tip. During drilling, compressed air, coolant or cooling oil is sprayed into the processing area through the internal cooling hole to quickly cool the machined surface and drill. sharp, reducing the cutting temperature of the tool. Compared with conventional drill bits, the internal cooling drill bit has better working performance, which can reduce the damage to the drill bit caused by high temperature during high-speed machining and prolong its service life.

The currently used internal coolant drills mainly include central single hole internal coolant drill, double cooling tube internal coolant drill and double spiral hole internal coolant drill. Among them, the processing effect of double screw hole internal coolant drill is better. However, there is a common problem with the currently used internal cooling drill bits, that is, when the coolant is directly sprayed from the shank of the drill bit to the drill tip through the cooling hole, although it has a certain cooling effect on the cutting edge and the drill tip area, the coolant has a certain cooling effect on the drill bit. The coverage of the cutting edge and the drill tip and the flow of coolant are insufficient, the distribution of the cooling surface is unreasonable, and there is not enough scouring effect on the chips accumulated at the edge groove, and the chip removal effect is not ideal. In addition, the cross-section of the cooling channel of the current internal cooling drill is mostly regular circle, and the size of the internal cooling channel lacks design basis, and the technical advantages of the internal cooling process have not been fully utilized.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a tool with an internal cooling jet structure in view of the defects of the prior art, the cooling channel can transport the cooling liquid, the cooling liquid is ejected from the outlet of the drill tip and the side jet holes, and the output of the outlet is dispersed The atomized coolant can cool and lubricate the cutting position, and the coolant jet output from the jet hole can flush the chips out of the drill bit groove, so as to meet the cooling and lubrication requirements.

A tool with an internal cooling jet structure adopts the following scheme:

It includes a drill bit, a helical cooling channel is arranged in the drill bit, and one end of the cooling channel extends to the drill tip as an outlet; the cooling channel communicates with the outside through the pre-set jet holes on the side of the drill bit, and the cooling channel close to the outlet is provided with a constriction part to shrink The radial cross-sectional area of the cooling channel is smaller than that of the other areas of the cooling channel, so that the cooling liquid is atomized at the outlet position.

Further, the trajectory line of the cooling channel is the same as the land line trajectory line of the drill bit, and the cooling channel and the side surface of the drill bit are kept at a distance.

Further, the locus of the cooling channel is arranged in parallel with the locus of the land, and along the radial direction of the drill bit, the cross-sectional shape of the cooling channel and the cross-sectional shape of the drill bit groove are similar figures.

Further, the jet hole is located in the blade groove, one end of the jet hole in the axial direction is connected to the cooling channel, and the other end extends to the blade groove.

Further, each edge groove is provided with a jet hole, and along the extending direction of the edge groove, the plurality of jet holes are arranged at intervals in sequence.

Further, the drill bit is provided with a plurality of cooling channels, and the cooling channels and the margins are arranged in a one-to-one correspondence.

Further, the cooling passage between the constriction portion and the outlet forms an expansion section, and the cooling passage between the constriction portion and the drill shank forms a conveying section; in the radial direction of the drill bit, the cross-sectional area of the conveying section is larger than that of the expanding section.

Further, the outlet is located on the rear of the drill tip of the drill bit, and outlets are arranged on the rear of both sides of the axis of the drill bit.

Further, the drill shank is provided with a straight hole channel, one end of the straight hole channel is connected to one end of the spiral channel away from the outlet, and the other end of the straight hole channel extends to the end of the drill shank as an inlet.

Further, the straight hole passages are in one-to-one correspondence with the helical passages, and a plurality of straight hole passages are arranged at intervals around the axis of the drill bit.

Compared with the prior art, the present invention has the following advantages and positive effects:

(1) In view of the problem of poor cooling effect in the current drill tool processing, the coolant is transported through the cooling channel, and the coolant is sprayed from the outlet of the drill tip and the side jet holes, and the dispersed and atomized coolant output from the outlet can be used for cutting Cooling and lubrication are carried out at the position, and the coolant jet output from the jet hole can flush the chips out of the groove of the drill bit, so as to meet the cooling and lubrication requirements.

(2) The drill is provided with a conformal internal cooling helical cooling channel and a jet hole located in the edge groove. The high-pressure coolant can reach the drill tip and the edge groove of the drill bit respectively, which has a good cooling and lubricating effect on the drilling area. At the same time, the chips accumulated at the drill tip and the groove can be discharged in time, which helps to reduce the wear of the drill bit.

(3) The cross-sectional shape of the inner cooling helical cooling channel of the drill is similar to the cross-sectional shape of the groove. At the same time, the trajectory of the cooling channel is the same as the distribution trajectory of the cutting edge of the drill and the distribution trajectory of the groove, which can improve the cooling liquid. For the cooling effect of the cutting edge and the drill tip of the drill, the cooling channel is close to the land and the groove, which can cool the land and groove from the inside in advance, and can also achieve a more reasonable coolant flow distribution.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

FIG. 1 is a schematic diagram of the external structure of the drill bit in Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of the distribution of cooling channels inside the drill bit in Example 1 of the present invention.

FIG. 3 is a schematic diagram of the expansion section of the cooling passage in the drill bit in Embodiment 1 of the present invention.

4 is a schematic view of the end face of the drill tip of the drill bit in Embodiment 1 of the present invention.

FIG. 5 is a schematic diagram showing the comparison of the fluid dynamics simulation results of the cooling channel when the inlet pressure is 20 bar in Example 1 of the present invention.

FIG. 6 is a schematic diagram showing the comparison of the fluid dynamics simulation results of the cooling channel when the inlet pressure is 30 bar in Example 1 of the present invention.

FIG. 7 is a schematic diagram showing the comparison of the results of the distribution law of the jet hole flow field in Example 1 of the present invention.

In the figure, 1, drill shank, 2, drill bit, 3, edge groove, 4, outlet, 5, straight hole channel, 6, cooling channel, 7, straight hole, 8, straight hole, 9, straight hole, 10, straight Hole, 11, straight hole, 12, constriction, 13, expansion section.

Detailed ways

Example 1

In a typical embodiment of the present invention, as shown in FIGS. 1-7 , a tool with an internal cooling jet structure is provided.

As shown in Figures 1 and 2, a tool with an internal cooling jet structure is used for drilling difficult-to-machine materials, especially the drill 2 with a double helical edge groove 3, and a cooling channel 6 is provided inside as a conformal internal Cold high-pressure jet structure, high-pressure coolant is directly injected into the internal cooling channel 6 from the drill bit 2, shank 1 during the drilling process, and the coolant is ejected from the outlet 4 of the cooling channel 6 at the drill tip and the straight hole of the jet hole at the edge groove 3, which plays a role in The function of cooling and lubricating and flushing the chips out of the groove 3 of the drill bit 2 can prolong the life of the drill bit 2 and improve the processing quality. It is suitable for high-speed and high-efficiency drilling of difficult-to-machine materials such as superalloy and hardened steel.

As shown in Figure 1, a tool with an internal cooling jet structure mainly includes a drill bit 2, a shank 1 and a main body of the drill bit 2. The two parts are integral structures, which can ensure the rigidity of the tool and facilitate processing stability.

As shown in FIG. 2 , the drill bit 2 is provided with a helical cooling channel 6 , and one end of the cooling channel 6 extends to the drill tip of the drill bit 2 as the outlet 4 . The cooling channels 6 can be arranged in multiples, arranged in the main body of the drill bit 2, corresponding to the number of the helical edge grooves 3 on the drill bit 2. When multiple cooling channels 6 are arranged, all the cooling channels 6 are circumferentially spaced around the axis of the drill bit 2. The cooling channels 6 are arranged and distributed apart from each other, and each cooling channel 6 can cool the drill bit 2 independently.

The cooling channel 6 communicates with the outside through the jet holes preset on the side of the drill bit 2, and the cooling channel 6 close to the outlet 4 is provided with a constriction 12, and the radial cross-sectional area of the constriction 12 is smaller than that of other areas of the cooling channel 6, so as to Atomize the coolant at the outlet 4 position.

The drill shank 1 of the drill bit 2 is provided with a straight hole channel 5, one end of the straight hole channel 5 is connected to the end of the spiral channel away from the outlet 4, and the other end of the straight hole channel 5 extends to the end of the drill shank 1 of the drill bit 2 as an entrance.

As shown in FIG. 2 , in this embodiment, taking the arrangement of two cooling channels 6 and two straight hole channels 5 in the drill bit 2 as an example, the two straight hole channels 5 in the drill shank 1 are arranged symmetrically with respect to the axis of the drill bit 2 , two symmetrically arranged cooling channels 6 located in the main body of the drill bit 2 , the straight hole channels 5 are in one-to-one correspondence with the helical channels, and a plurality of straight hole channels 5 are arranged at intervals around the axis of the drill bit 2 .

The helix angle and pitch of the cooling channel 6 in the drill bit 2 are consistent with the edge groove 3, the trajectory line of the cooling channel 6 is the same as the margin trajectory line of the drill bit 2, and the cooling channel 6 and the side surface of the drill bit 2 keep a distance to ensure the cutting of the end of the drill bit 2. The cutting edge of the edge and the outer wall of the drill bit 2 has a good cooling effect.

Straight holes communicated with the cooling channel 6 are evenly distributed at the edge groove 3 of the drill bit 2. The straight hole is used as a jet hole for outputting the cooling liquid to form a jet. The liquid jet has a sufficient pressure to scour the chips at the edge groove 3.

Taking the double helical drill bit 2 as an example, two cooling channels 6 are arranged correspondingly. The two cooling channels 6 of the drill bit 2 are symmetrically arranged in the main body of the drill bit 2 near the margin cutting edge on the side, and the jet hole is located in the edge groove 3. One end of the axial direction is connected to the cooling channel 6, and the other end extends to the edge groove 3; each edge groove 3 is provided with a jet hole, and along the extending direction of the edge groove 3, a plurality of jet holes are arranged at intervals.

It can be understood that, as shown in FIG. 1 , the number of jet holes at the groove 3 is adjusted according to the number of cutting edges and the pitch of the land on the side wall, and the spacing of the straight holes can be configured to be equal to the pitch of the groove 3 .

As shown in Figure 2, there are a plurality of cooling channels 6 in the head, and the cooling channels 6 are arranged one-to-one with the land. The line and the margin trajectory line are arranged in parallel, along the radial direction of the drill bit 2, the cross-sectional shape of the cooling channel 6 is similar to the cross-sectional shape of the drill bit 2 edge groove 3, so as to ensure that the coolant flow can be reasonably distributed according to the cutting edge position and give full play to cooling and lubrication. Effect.

As shown in FIG. 4 , the distance a between the outer edge contour of the cooling channel 6 and the outer contour of the main body of the drill bit 2 and the edge groove 3 is 0.3 times the radius of the drill bit 2 (ie R ₁ ). The center distance of the drill bit 2 is also 0.3 times the radius of the drill bit 2. The arc of the inner edge of the cooling channel 6 is obtained by rounding the two curved segments close to both sides of the edge groove 3. The radius value R ₂ is about 0.12 of the radius of the drill bit 2. times.

The cooling channel 6 between the constricted portion 12 and the outlet 4 forms the expansion section 13, and the cooling channel 6 between the constricted portion 12 and the drill shank 1 of the drill bit 2 forms the conveying section, as the conventional section of the inner spiral hole as shown in FIG. 2; The shank 1 is used as the straight hole section of the drill bit 2; along the radial direction of the drill bit 2, the cross-sectional area of the conveying section is larger than that of the expansion section 13, and the constricted section 12 forms the constricted section.

Specifically, in this embodiment, as shown in FIGS. 2 and 3 , the cooling passage 6 of the drill bit 2 includes three parts: a normal section, a constricted section and an expanded section 13 , wherein the cooling passage 6 near the drill tip is constricted-expanded section 13 The total length is 1/8 of the length of the main body of the drill bit 2, the ratio of the length of the cooling channel 6 constriction section to the expansion section 13 is 2:1, the cross section of the conventional section of the cooling channel 6, the cross section of the contraction-expansion interface (i.e. throat), the outlet The ratio of the dimensions of the four cross-sections (that is, the projected area of the outlet 4 of the drill tip of the cooling channel 6 in the axial direction of the drill bit 2) is 7:5:6.

The contraction-expansion structure of the inner cooling channel near the drill tip of the drill bit 2 can increase the spray speed of the coolant at the outlet 4 of the drill bit 2 and improve its atomization degree, so as to give full play to the cooling and lubricating effect of the cooling channel 6; as shown in Figure 4, The outlet 4 is located on the rear of the drill tip of the drill bit 2 , and the outlet 4 is arranged on the rear of both sides of the axis of the drill bit 2 .

The diameter of the jet hole at the edge groove 3 is 0.05-0.1 times the diameter of the main body of the drill bit 2, so as to take into account the dual requirements of the overall strength of the drill bit 2 and the flow of coolant.

As shown in Figure 1, the selection range of the apex angle α of the drill bit 2 is 120°-140°, the specific angle value can be determined according to the material properties of the workpiece to be processed, and a larger apex angle can be selected when the material strength is higher; When different apex angles are selected, the distribution ratio of the axial drilling force and the radial drilling force during the drilling process can be changed, so as to enhance the stability of the machining process and ensure that the drill bit 2 has sufficient rigidity and drilling stability.

In addition, in this embodiment, the selection range of the helix angle of the drill bit 2 is 20°-40°, and the specific angle can be determined according to the material properties of the workpiece to be machined. When machining high-viscosity and difficult chip-breaking materials, a larger helix can be appropriately selected. horn.

Among them, the drill bit 2 is made of ultra-fine grained cemented carbide as a whole, and the surface is coated with TiAlN coating, which can take into account excellent tool toughness, high temperature strength and wear resistance of the tool, and can realize efficient drilling of difficult-to-machine materials, ensuring processing quality and safety. Drill 2 life.

The surface roughness of the groove 3 of the drill bit 2 is _Ra =0.15 to reduce the friction between the chips and the surface of the groove 3 and the adhesive wear of the groove 3 of the drill 2, and to ensure the smooth discharge of the chips.

As shown in Figure 5 and Figure 6, the straight hole is used as the jet hole, and the straight hole 7, the straight hole 8, the straight hole 9, the straight hole 10, the straight hole 11 and the outlet 4 are selected for flow and flow rate detection, and the conventional cooling channel is arranged. The drill bit 2 of 6 is compared with the drill bit 2 in this embodiment, wherein the cross-sectional area of the cooling channel 6 of the conventional circular cross-section inner cooling drill bit 2 is equal to the cross-sectional area of the cooling channel 6 of the drill bit 2 in this embodiment.

Figures 6 and 5 are the comparison of the coolant flow rate of each jet hole of the drill bit 2 in this embodiment and the conventional circular cross-section inner cooling channel drill bit 2 under different coolant inlet pressure conditions (take 20bar and 30bar as an example). The flow velocity at the position of the jet hole in the flute 3 and the outlet 4 of the drill tip is shown in Fig. The results show that under the same inlet pressure conditions, the coolant flow rate of each jet hole and outlet 4 in this embodiment is higher than that of the conventional circular cross-section internal cooling bit 2, and the coolant flow rate is larger, and the coolant flow rate and flow rate are the highest. It can be increased by more than 30%.

Fig. 7 shows the distribution law of the cooling liquid flow velocity of each outlet 4 of the drill bit 2 and the conventional circular cross-section inner cooling drill bit 2 in this embodiment when the inlet cooling liquid pressure is 20 bar. It can be seen that at the position of each cooling liquid outlet 4, this embodiment In the example, the flow rate of the cooling liquid at the outlet 4 of the drill bit 2 is significantly higher than that of the conventional circular cross-section coolant drill bit 2, and the flow rate of the outer contour area of the cooling channel 6 near the cutting edge is the highest.

Based on the above results, the arrangement of the cooling channel 6 in the drill bit 2 in this embodiment can bring a better cooling effect to the machining process, and the cooling efficiency is higher, which will help to ensure the difficult-to-machine structure of deep holes and the drilling of difficult-to-machine materials. processing efficiency and surface quality.

Compared with the prior art, the drill bit 2 of this embodiment is provided with a conformal cooling channel 6 and straight holes at 3 edge grooves, and the high-pressure coolant can reach the drill tip and 3 edge grooves respectively, which has a good effect on the drilling area. Cooling and lubricating effects, and at the same time, the chips accumulated at the drill tip and the edge groove 3 can be discharged in time, which helps to reduce the wear of the drill bit 2.

The cross-sectional shape of the cooling channel 6 of the drill bit 2 in this embodiment is a conformal shaped structure, and the contour of the inner cooling channel is similar to the contour of the cutting edge of the drill bit 2 and the edge groove 3, which can improve the cooling of the coolant on the cutting edge and the drill tip of the drill bit 2. effect and achieve better and reasonable coolant flow distribution.

The drill bit 2 of the present embodiment has a simple structure and is convenient to use, and the production and processing costs of the drill bit 2 are low, which is favorable for large-scale promotion and application. At the same time, the cooling channel 6, the straight hole channel 5 and the jet hole structure given in this embodiment can also be applied to the integral drill bit 2 and the interchangeable head drill bits 2 such as crown drills and spade drills, and can be extended to other rotary drills. Tool structure for machining.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A cutter with an internal cooling jet structure, characterized in that it comprises a drill bit, and a helical cooling channel is arranged in the drill bit, and one end of the cooling channel extends to the drill tip as an outlet; The jet hole communicates with the outside, and the cooling channel close to the outlet is provided with a constricted portion, and the radial cross-sectional area of the constricted portion is smaller than that of other regions of the cooling channel, so that the cooling liquid is atomized at the outlet. 2 . The tool with an internal cooling jet structure according to claim 1 , wherein the trajectory line of the cooling channel is the same as the land line trajectory line of the drill bit, and the cooling channel and the side surface of the drill bit maintain a distance. 3 . 3 . The tool with internal cooling jet structure according to claim 2 , wherein the trajectory line of the cooling channel is arranged in parallel with the trajectory line of the land, and along the radial direction of the drill bit, the cross-sectional shape of the cooling channel is the same as the drill bit groove. 4 . The cross-sectional shape is similar. 4 . The tool with internal cooling jet structure according to claim 1 , wherein the jet hole is located in the blade groove, one end of the jet hole axially communicates with the cooling channel, and the other end extends to the blade groove. 5 . 5. The tool with an internal cooling jet structure according to claim 1 or 4, wherein a jet hole is arranged in each edge groove, and along the extending direction of the edge groove, a plurality of jet holes are arranged at intervals in sequence . 6 . The tool with an internal cooling jet structure according to claim 1 , wherein the drill bit is provided with a plurality of cooling channels, and the cooling channels are arranged in a one-to-one correspondence with the land. 7 . 7 . The tool with internal cooling jet structure according to claim 1 , wherein the cooling channel between the constriction part and the outlet forms an expansion section, and the cooling channel between the constriction part and the drill shank forms a conveying section. 8 . In the radial direction of the drill bit, the cross-sectional area of the conveying section is larger than that of the expansion section. 8 . The tool with an internal cooling jet structure according to claim 7 , wherein the outlet is located on the rear of the drill tip of the drill bit, and outlets are arranged on the rear surfaces of both sides of the axis of the drill bit. 9 . 9 . The tool with an internal cooling jet structure according to claim 1 , wherein the drill shank is provided with a straight hole channel, one end of the straight hole channel is connected to one end of the spiral channel away from the outlet, and the other end of the straight hole channel is connected. 10 . One end extends to the end of the drill shank as an entry. 10 . The tool with an internal cooling jet structure according to claim 9 , wherein the straight hole channels and the helical channels are in one-to-one correspondence, and a plurality of straight hole channels are arranged at intervals around the axis of the drill bit. 11 .

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