Internal cooling hot shrinkage knife handle

Abstract

The utility model relates to an internal cooling and thermal shrinkage cutter handle which comprises a cutter handle body, the cutter handle body is provided with a first cooling channel extending in the axial direction of the cutter handle body and a cutter clamping hole, and the cooling channel and the cutter clamping hole are coaxial, arranged in the middle and communicated with each other; the end cover is fixed on the front end face of the cutter handle body and is provided with a cutter hole communicated with the cutter clamping hole; the cutter handle body further comprises a plurality of second cooling channels, the end cover further comprises a plurality of jet holes, and the second cooling channels are obliquely arranged relative to the axial direction of the cutter handle body. And the first cooling channel, the plurality of second cooling channels and the plurality of spraying holes are sequentially communicated to form a cooling flow channel for cooling a to-be-mounted cutter or a to-be-machined workpiece. According to the internal cooling tool holder, the internal cooling runner in the tool holder is redesigned, so that the internal cooling tool holder is matched with a conventional tool without an internal cooling hole, the application range of the internal cooling tool holder is expanded, and the use cost of the tool is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of machine tools, and in particular to an internally cooled heat shrinkable tool holder. Background Art

[0002] The principle of the heat shrink tool holder is to use the difference in thermal expansion coefficients between the tool holder (special stainless steel) and the tool (carbide) to clamp the tool with high force and precision. The hot-loading system is as accurate as a hydraulic tool holder, and the run-out range is about 0.0025mm. The tool holder material uses special stainless steel for hot-loading with a large thermal expansion coefficient, which enables low-temperature hot-loading at 300°C. It brings together 3,500 tool holders of different shapes, which can cope with all processing scenarios such as milling, drilling, and reaming from high-speed finishing to heavy cutting. The installation part of the heat shrink tool does not require components such as nuts and collets required for collet chucks. The simple, ultra-slender shape can set the protruding length of the tool to the shortest, obtaining a strong and stable clamping force, thereby ensuring high precision.

[0003] Researchers at home and abroad have developed a series of new green processing technologies for these materials, such as minimal lubrication processing technology, low-temperature cold air minimal lubrication processing technology, liquid nitrogen minimal lubrication processing technology, supercritical CO2 minimal lubrication processing technology, etc. However, the application of the technology is inseparable from the support of equipment and key functional components.

[0004] There are two ways to apply supercritical CO2 minimal lubrication processing technology in actual applications. One is the external spraying method, which is mainly used in conventional machine tools (without internally cooled spindles). It is necessary to set up a nozzle at a suitable position near the machine tool spindle and manually adjust the position of the nozzle to achieve precise cooling and lubrication of the tool after supercritical CO2 injection. However, due to the influence of the workpiece structure, the fixture structure, the machine tool structure, etc., the nozzle arrangement of this method is often affected, resulting in inadequate supercritical CO2 injection, which seriously affects the cooling and lubrication effect of the tool. The other is the internal spraying method, which is mainly used in internally cooled machine tools and needs to be used with internally cooled tool holders and internally cooled tools. The advantage of this method is that it does not require the installation of a nozzle, and the outlet of the supercritical CO2 on the tool is very close to the cutting edge, which can effectively cool and lubricate the tool and the cutting area. But for internally cooled tools, internally cooled drills have internal cooling holes directly on the drill bit to achieve internal cooling, which is more common, while internally cooled milling cutters, taps, etc. are rare. In addition, the cost of tools with internal cooling holes is relatively high. In view of the above reasons, the application of supercritical CO2 internal spraying is subject to certain restrictions.

[0005] The applicant's earlier utility model patent CN210789416U discloses an externally cooled to internally cooled tool holder and an externally cooled to internally cooled tool holder assembly, wherein the cutting fluid or oil-gas mixture is passed through the clamping hole (112) into the internal cooling hole (210) of the tool head (200). CN103025483A discloses a tool holder, wherein part of the cutting oil is discharged through a third flow path (50), and a limiting member (40) is provided to prevent the cover (20) from rotating with the rotation of the tool mounting portion (2B). The tool holder of the prior art is a collet-type tool holder, and the collet is separable from the tool holder body. The above configuration structure also needs to consider the sealing problem at the connection, and the structure is relatively complex, and cannot be transferred to the heat shrink tool holder intact for application, and the heat shrink tool holder also requires a feasible internal cooling method to adapt to specific application scenarios. Utility Model Content

[0006] In order to overcome at least one of the defects of the prior art described above, the present application provides an internal cooling heat shrinkable tool holder, comprising:

[0007] A tool handle body, which has a first cooling channel and a tool clamping hole extending along the axial direction of the tool handle body, wherein the cooling channel and the tool clamping hole are coaxial and interconnected, and are both centrally arranged;

[0008] An end cover, fixedly mounted on the front end surface of the tool handle body, and having a tool hole communicated with the tool clamping hole;

[0009] The tool holder body also includes a plurality of second cooling channels, and the end cover also includes a plurality of injection holes, and the injection holes are arranged through the front and rear end surfaces of the end cover, wherein the second cooling channels are arranged obliquely relative to the axial direction of the tool holder body, and the injection holes are arranged parallel to the axial direction of the tool holder body or obliquely from back to front to the tool hole, and the first cooling channel, the plurality of the second cooling channels and the plurality of the injection holes are connected in sequence to form a cooling flow channel for cooling the tool to be installed or the workpiece to be processed; the rear end surface of the end cover corresponding to the second cooling channel portion extends forward to form an annular groove, and the corresponding front end surface of the tool holder body extends forward into the annular groove, and the front end portion of the second cooling channel extends into the annular groove.

[0010] Furthermore, the front end portion of the shank body and the annular groove of the end cover form a cooling medium transition cavity, and a plurality of the second cooling channels and a plurality of the injection holes are connected through the cooling medium transition cavity.

[0011] Furthermore, the diameter dr of the injection hole satisfies the following conditions:

[0012]

[0013] Among them, d represents the diameter of the tool holding hole, N is the number of injection holes, and K1 is the coefficient factor, which ranges from 0.02 to 2.15.

[0014] Furthermore, the overhanging length of the tool to be installed extending from the end cover satisfies the following conditions:

[0015] L=(0.0872d 2 +0.1428d+16.26)×K2

[0016] Wherein, L represents the overhang length, d represents the diameter of the tool holding hole, and K2 is a coefficient factor, and its value range is between 0.4 and 1.5.

[0017] Furthermore, the number of the plurality of injection holes is 1 to 15.

[0018] Furthermore, the diameter of the injection hole is in the range of 0.08 mm to 0.8 mm, inclusive.

[0019] Furthermore, the value range of K1 is 0.14-1.15.

[0020] Furthermore, an angle of the injection hole relative to the axial direction of the shank body is in the range of 0° to 45°.

[0021] Furthermore, the diameter of the second cooling channel is greater than the diameter of the injection hole.

[0022] Furthermore, the number of the plurality of injection holes is 2-7.

[0023] The end cap of the internally cooled heat shrinkable toolholder of the present application is fixedly installed at the front end of the toolholder body, and the rear end face of the end cap is provided with an annular groove, and the front end face portion of the toolholder body extends forward into the annular groove, thereby enhancing the sealing performance, preventing coolant leakage, and weakening the cooling effect. The present application also achieves the matching of the internally cooled toolholder with conventional tools without internal cooling holes by redesigning the internal cooling flow channel of the toolholder, so that the internal cooling medium can be sprayed through the internally cooled toolholder to cool and lubricate conventional tools without internal cooling holes or processed workpieces, thereby expanding the application range of the internally cooled toolholder and reducing the cost of the tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1A front view of an internally cooled heat shrinkable tool handle according to an embodiment of the present application is shown;

[0026] Figure 2a and 2b They are shown respectively Figure 1 Axial cross-sectional views of the internally cooled heat shrinkable tool holder with and without a tool according to the illustrated embodiment;

[0027] Figure 3 A bottom view of the end surface of the end cap facing away from the handle body according to an embodiment of the present application is shown;

[0028] Figure 4 Shows Figure 3 A partial cross-sectional view of the end face of the end cap of the illustrated embodiment facing away from the handle body; and

[0029] Figure 5 An axial cross-sectional view of an internally cooled heat shrinkable tool holder including a vent hole according to another embodiment of the present application is shown.

[0030] List of reference numerals:

[0031] 1-Internal cooling heat shrink handle; 2-Handle body; 3-End cover; 4-First cooling channel; 5-Tool clamping part; 6-Second cooling channel; 7-Tool hole; 8-Injection hole; 9-Cooling medium transition groove; 10-Concave part; 11-Snap groove; 12-Connecting pipe; 13-Seal; 14-Connecting pipe inclined surface; α-Angle; N-Number of injection holes; D-Diameter of the front end face of the handle body; d-Diameter of the tool clamping hole; d r - injection hole diameter; e-inner wall thickness; f-outer wall thickness; T-tool; 15-vent hole. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] In the description of the present application, it should be understood that the terms "X-axis", "Y-axis", "Z-axis", "vertical", "parallel", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

[0034] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] like Figure 1 , 2aAs shown in Figures 2 and 2b, the internal cooling heat shrinkable tool holder 1 of the present application includes a tool holder body 2 and an end cover 3. The tool holder body 2 is roughly cylindrical in form, and it is conceivable that it has a virtual center axis (not shown) extending along its own axial direction. The tool holder body 2 has a first cooling channel 4 extending along its axial direction, and the first cooling channel 4 is located in the rear end section of the tool holder body 2. The tool holder body 2 also has a tool clamping hole 5 extending along its axial direction, and the tool clamping hole 5 is located in the front end section of the tool holder body 2. Considering that the first cooling channel must receive a cooling medium, such as supercritical CO2, from the internal cooling hole (not shown) of the machine tool spindle, the ideal arrangement of the first cooling channel 4 is to extend along the virtual center axis of the tool holder body 2. On the other hand, in view of the working conditions of the rotating tool, the tool clamping hole 5 also extends along the virtual center axis of the tool holder body 2. This means that the first cooling channel 4 and the tool clamping hole 5 are both centrally arranged in the longitudinal direction of the tool holder body 2 and are coaxial with each other. Further, the first cooling channel 4 and the tool clamping hole 5 are connected to each other. The handle body 2 further includes a plurality of second cooling channels 6, preferably two second cooling channels 6, which are symmetrically distributed on both sides of the tool clamping hole 5 about the virtual center axis of the handle body 2. One end of each second cooling channel 6 is connected to the front end of the first cooling channel 4, and the other end of the second cooling channel 6 is arranged at the front end surface of the handle body 2 and is arranged away from the tool clamping hole 5 along the radial direction of the handle body 2. In this way, the second cooling channel 6 forms a certain angle relative to the axial direction of the handle body 2.

[0036] The cooling medium in the present application may be a common cooling fluid in the art, such as supercritical carbon dioxide, cooling water, etc.

[0037] The end cap 3 is fixed (for example, welded) to the front end face of the shank body 2. In order for the tool to be installed to extend into the internal cooling heat shrink shank 1, a tool hole 7 is provided at the center of the end cap 3. The end cap 3 also has a plurality of injection holes 8 connected to the second cooling channel 6. The extension direction of the injection holes is parallel to the axial direction of the shank body 2, or the end of the injection hole 8 away from the second cooling channel 6 is arranged radially closer to the tool hole 7 relative to the end close to the second cooling channel 6, that is, it is arranged obliquely from back to front toward the tool T. Specifically, the angle of the extension direction relative to the axial direction of the shank body 2 is in the range of 0° to 45°, including this number. And preferably, the angle is 3-20°.

[0038] In a preferred embodiment, the middle portion of the front end face of the handle body 2 extends forward to form a protrusion, and correspondingly, the rear end face of the end cover 3 is designed to extend forward in the middle portion to form an annular groove, which is complementary to the protrusion shape of the front end face of the handle body 2 so as to cooperate with each other. In this embodiment, the front end portion of the second cooling channel 6 extends into the annular groove, that is, the second cooling channel is connected to the annular groove, and the injection hole is connected to the annular groove. Combined with the fixed connection (for example, welding) of the end cover 3 and the handle body 2, the end cover 3 forms a U-shaped seal for the handle body 2, and is integrated by welding and the like, thereby reducing the enclosed space between the two (the end cover 3 and the handle body 2), enhancing its airtightness, and thus reducing the risk of leakage of the cooling medium.

[0039] The annular groove of the end cover 3 and the front end of the shank body form a cooling medium transition chamber 9, which is connected to the two second cooling channels 6; on the other hand, the injection hole 8 is connected to the cooling medium transition chamber 9. In this way, even if the injection hole 8 does not correspond one-to-one to the two second cooling channels 6, the cooling medium can first flow into the cooling medium transition chamber 9 and then flow into the injection hole 8. Therefore, the first cooling channel 4, the second cooling channel 6, the cooling medium transition chamber 9 and the injection hole 8 together constitute a cooling flow channel for the tool T to be installed or the workpiece to be processed, so as to spray the cooling medium onto the tool T or the workpiece to be processed. Since the injection hole 8 does not have to correspond one-to-one to the two second cooling channels 6, the number of injection holes 8 that can be configured does not have to be limited to two, and can be designed to be 1 to 15.

[0040] The diameter dr of the injection hole 8 is:

[0041]

[0042] Wherein, d represents the diameter of the tool holding hole 5, that is, the tool mounting diameter, N is the number of injection holes, and K1 is a coefficient factor, and its value range is between 0.02 and 2.15.

[0043] The total cross-sectional area of ​​the jet holes is related to the diameter and number of the jet holes. On the one hand, it is hoped that the area of ​​the tool radiated by the jet is large enough to ensure a good cooling effect, that is, a large number of jet holes and large jet holes are more conducive to uniform injection of the cooling fluid; on the other hand, within this radiation area, the supply of supercritical equipment must also be considered. If the jet holes are too large or there are too many jet holes, the pressure will be released too quickly, and the pressurization unit at the supercritical supply end will not be able to increase the pressure in time, which will lead to a shortage of supply and thus affect the cooling effect. And if there are too many or large jet holes, it may affect the mechanical strength of the tool, thereby affecting the cutting effect, and also increasing the difficulty of processing. The number of jet holes is 1-15.

[0044] Moreover, when the tool diameter is relatively large, it indicates that the machining cutting amount is large. At this time, more cooling is required, and more spray holes should be set to increase the spray coverage range, that is, the total cross-sectional area of ​​the corresponding spray holes is relatively large, that is, the tool diameter is related to the total cross-sectional area of ​​the spray holes.

[0045] Therefore, based on the above analysis, the tool diameter has a great influence on the cooling effect. The tool diameter is established as a function relationship by data fitting. During the data fitting process, regression analysis is performed on the point values ​​that deviate from the curve. In addition, since data regression analysis is performed during the fitting process, there is a deviation between the tool diameter obtained by the above function and the total cross-sectional area of ​​the injection holes. Therefore, in order to correct the deviation, a correction coefficient is added, and the diameter and number of the injection holes are also related to the total cross-sectional area of ​​the injection holes. Thus, an equation is established and a data fitting relationship is formed as shown in Formula 1.

[0046] According to the above functional relationship, when the tool diameter is known, the appropriate number of injection holes is selected, and the diameter of the injection hole with better cooling effect can be obtained according to the above functional relationship.

[0047] Furthermore, the value range of K1 is 0.14-1.15, the number of injection holes is preferably 2-7, and the tool diameter is preferably 4-10 mm.

[0048] In one embodiment, the tool diameter is 4 mm, the tool clamping hole diameter is 4 mm, and the number of injection holes is 2. At this time, the coefficient factor K1 takes a value of 0.14. According to the above formula (1), it can be calculated that the diameter of the injection hole should be set to 0.32 mm.

[0049] In another embodiment, the diameter of the tool clamping hole is set to 6 mm, the number of injection holes is 4, and the coefficient factor K1 is 0.44. According to the above formula (1), it can be calculated that the diameter of the injection hole should be set to 0.4 mm.

[0050] In another embodiment, the diameter of the tool clamping hole is set to 10 mm, the number of injection holes is 6, and the coefficient factor K1 is 0.91. According to the above formula (1), it can be calculated that the diameter of the injection hole should be set to 0.48 mm.

[0051] Preferably, the diameter of the injection hole 8 is set in the range of 0.08 mm to 0.8 mm, inclusive.

[0052] The cross-sectional area of ​​the injection hole 8 is relatively small to ensure that the pressure drop loss of the cooling medium is reduced. Therefore, in order to reduce the processing difficulty of the cooling channel, a two-stage cooling channel is set, namely, including the second cooling channel 6 and the injection hole 8, and the cross-sectional area of ​​the injection hole 8 is smaller than the cross-sectional area of ​​the second cooling channel 6.

[0053] Due to the presence of the injection hole 8, the end cover 3 can also use the injection hole 8 as a reference to limit the design dimensions of other parts. Figure 3 , 4 And 5, the inner wall thickness e is the distance from the inner wall of the tool hole 7 of the end cover 3 to the inner edge of the injection hole 8 on the corresponding side, which satisfies the following conditions:

[0054] 0≤e≤D / 2-d / 2-d r (2)

[0055] Where D is the diameter of the front end face of the front end cover, d is the diameter of the tool hole 7, and d r Indicates the diameter of the injection hole 8.

[0056] Furthermore, the outer wall thickness f is the distance from the outer edge of the end cover 3 to the outer edge of the injection hole 8, which satisfies the following conditions:

[0057] 0≤f≤D / 2-d / 2-d r (3)

[0058] The symbols in formula (3) except for the wall thickness f are the same as those in formula (2) and are not repeated here.

[0059] Furthermore, in order to make the cooling medium spray out from the spray hole to cool the tool most effectively, after the tool T is installed in the internal cooling heat shrinkable tool holder 1, the tool T extends from the tool hole 7 of the end cover 3, and its overhang length L can be defined as:

[0060] L=(0.0872d 2 +0.1428d+16.26)×K2 (4)

[0061] Among them, K2 is the coefficient factor, and its value range is between 0.4 and 1.5.

[0062] In one embodiment, the tool mounting diameter is 4 mm, and the diameter of the tool clamping hole is 4 mm. At this time, the coefficient factor K2 takes a value of 0.79. According to the above formula (4), it can be calculated that the overhang length L should be set to 14.4 mm.

[0063] In another embodiment, the diameter of the tool clamping hole is set to 6 mm, and the coefficient factor K2 is set to 1.01. According to the above formula (4), it can be calculated that the diameter of the overhang length L should be set to 21.6 mm.

[0064] In another embodiment, the diameter of the tool holding hole is set to 8 mm, and the coefficient factor K2 is set to 1.16. According to the above formula (4), it can be calculated that the diameter of the injection hole should be set to 26.75 mm.

[0065] Furthermore, in order to ensure that the supercritical CO2 ejected from the injection hole can be sprayed onto the tool, the angle between the injection hole and the axis of the tool handle is set to 3-20°.

[0066] Considering that the internal cooling heat shrinkable tool holder 1 must be connected to the machine tool spindle, it is necessary to design the rear end section of the tool holder body 2 to be adaptable. Figure 2a-2b The middle part of the rear end face of the tool handle body 2 extends axially forward to form a recess 10, and the inner circumferential surface of the recess 10 has a snap-on groove 11, so that the tool handle body 2 and the machine tool spindle can be snap-connected like the common quick connectors on the market. A connecting pipe 12 is arranged inside the recess 10, and the front end of the connecting pipe 12 is connected to the first cooling channel 4, while the rear end is in the cavity defined by the recess 10 to communicate with the cooling channel of the spindle. Specifically, the connecting pipe 12 also extends along the virtual center axis of the tool handle body 2. In order to ensure that the connecting pipe 12 is connected to the tool handle body 2 and connected to the first cooling channel 4, a connecting piece (not shown) is provided, such as a threaded sleeve. Correspondingly, the bottom surface of the recess 10 and the corresponding part of the connecting pipe 12 are also provided with threads, so that the connecting pipe 12 is connected to the recess 10 through the connecting piece. Preferably, a seal 13, such as an O-ring, may be arranged on the connection interface between the connector and the connector tube 12, preferably two seals, one of which is preferably arranged at the interface between the connector tube 12 and the tool handle body 2, and the other is located above the flange of the connector tube 12 and in contact with the connector. The rear end of the connector tube 12 has an inclined surface 14, and when the tool handle body 2 and the machine tool spindle are close to each other through the snap connection, the inclined surface 14 is conducive to the close docking of the connector tube 12 and the inner cooling hole of the machine tool spindle, thereby realizing a sealed flow channel for the cooling medium from the machine tool spindle to the tool handle 1.

[0067] In other embodiments, a vent hole 15 is provided on the side wall of the rear end section of the handle body 2. Figure 5 As shown, the vent hole 15 is connected to the recess 10 and is used to discharge the cooling medium leaked from the connection between the spindle and the inner cooling tube to prevent the cooling medium from diffusing in the tool handle body and affecting the service life of the tool handle.

[0068] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the implementation methods of the present application. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application should be included in the protection scope of the claims of the present application.

Claims

1. An internally cooled heat shrinkable tool handle, characterized in that: include: A tool handle body, which has a first cooling channel and a tool clamping hole extending along the axial direction of the tool handle body, wherein the cooling channel and the tool clamping hole are coaxial and interconnected, and are both centrally arranged; An end cover, fixedly mounted on the front end surface of the tool handle body, and having a tool hole communicated with the tool clamping hole; The tool holder body also includes a plurality of second cooling channels, and the end cover also includes a plurality of injection holes, and the injection holes are arranged through the front and rear end surfaces of the end cover, wherein the second cooling channels are arranged obliquely relative to the axial direction of the tool holder body, and the injection holes are arranged parallel to the axial direction of the tool holder body or obliquely from back to front to the tool hole, and the first cooling channel, the plurality of the second cooling channels and the plurality of the injection holes are connected in sequence to form a cooling flow channel for cooling the tool to be installed or the workpiece to be processed; the rear end surface of the end cover corresponding to the second cooling channel portion extends forward to form an annular groove, and the corresponding front end surface of the tool holder body extends forward into the annular groove, and the front end portion of the second cooling channel extends into the annular groove.

2. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: The front end of the shank body and the annular groove of the end cover form a cooling medium transition cavity, and a plurality of the second cooling channels and a plurality of the injection holes are connected through the cooling medium transition cavity.

3. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: The diameter dr of the injection hole satisfies the following conditions: Among them, d represents the diameter of the tool holding hole, N is the number of injection holes, and K1 is the coefficient factor, which ranges from 0.02 to 2.

15.

4. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: The overhang length of the tool to be installed extending from the end cover meets the following conditions: Wherein, L represents the overhang length, d represents the diameter of the tool holding hole, and K2 is a coefficient factor, and its value range is between 0.4 and 1.

5.

5. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: The number of the plurality of injection holes is 1 to 15.

6. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: The diameter of the injection hole is in the range of 0.08 mm to 0.8 mm, inclusive.

7. The internally cooled heat shrinkable tool handle according to claim 3, characterized in that: The value range of K1 is 0.14-1.

15.

8. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: The included angle of the injection hole relative to the axial direction of the shank body is in the range of 0° to 45°.

9. The internally cooled heat shrinkable tool handle according to claim 1, characterized in that: A diameter of the second cooling channel is greater than a diameter of the injection hole.

10. The internally cooled heat shrinkable tool handle according to claim 1 or 4, characterized in that: The number of the plurality of injection holes is 2-7.

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