Power tool and tool head thereof

By setting a gradient radial cross section and multiple transition sections in the transition part of the tool head, shock wave reflection is reduced, and the hole-opening efficiency of the tool head is improved.

WO2026102903A1PCT designated stage Publication Date: 2026-05-21JIANGSU DONGCHENG M&E TOOLS CO LTD
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
JIANGSU DONGCHENG M&E TOOLS CO LTD
Filing Date
2025-01-15
Publication Date
2026-05-21

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Abstract

Disclosed in the present application are a power tool and a tool head thereof. The tool head comprises a tool body and a shank, wherein the tool body comprises a main body portion, an impact head located at one end of the main body portion, and a transition portion located at the other end of the main body portion; the shank is inserted into an impact power apparatus; the shank is connected to the end of the transition portion away from the main body portion, and the shank extends in the axial direction of the tool body; the transition portion has a first connecting end face connected to the shank and a second connecting end face connected to the main body portion; and the area of the second connecting end face is greater than that of the first connecting end face. In the present invention, the radial cross-sectional dimension of the transition portion gradually increases; and when a shock wave propagates inside the tool head, a generated reflected wave is small, such that more energy can be transferred to an object to be processed, thereby improving the impact efficiency.
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Description

Power tools and their tool heads Technical Field

[0001] This invention relates to the field of hardware tools, and more particularly to power tools and their tool heads. Background Technology

[0002] A tool head is a power tool accessory, typically used with an impact motor. Driven by the impact motor, the tool head creates holes or grooves in materials such as walls, floors, and wooden boards.

[0003] As shown in Figure 1, the existing tool head includes a tool body 10A and a shank 20A. The tool body 10A includes a first part 11A, an impact head 12A located at one end of the first part 11A, and a second part 13A located at the other end of the first part 11A. The second part 13A typically uses a single cylindrical design. To allow the tool head to be compatible with commercially available impact electric devices, the radial dimension of the shank 20A is usually fixed. The larger the diameter of the hole or slot that the tool head can drill, the larger the radial dimension of the first part 11A will be, and the larger the radial dimension of the second part 13A will also be. Therefore, the diameter difference between the shank 20A and the second part 13A will be greater, and the wave resistance between the shank 20A and the tool body 10A will be greater. Consequently, when the shock wave propagates inside the tool head, the reflected wave generated is larger, which reduces the energy transmitted to the workpiece, resulting in low drilling efficiency for the existing tool head. Summary of the Invention

[0004] To solve the above-mentioned technical problems and achieve at least one advantage of the present invention, the present invention provides a tool head, the tool head comprising:

[0005] The tool body includes a main body, an impact head located at one end of the main body, and a transition part located at the other end of the main body;

[0006] A shank for insertion into an impact electric device, the shank being connected to the end of the transition portion away from the main body, and the shank extending axially along the cutter body, the transition portion having a first connecting end face connected to the shank and a second connecting end face connected to the main body, the area of ​​the second connecting end face being larger than the area of ​​the first connecting end face;

[0007] The diameter of the first connecting end face is D min ;

[0008] The diameter of the second connecting end face is D max ;

[0009] The absolute value of the rate of change of radial cross-sectional area at any position along the direction extending from the first connecting end face to the second connecting end face of the transition section never exceeds 3 × (D). max -D min The value is shown as greater than zero.

[0010] According to one embodiment of the present invention, the single-sided contour line of the outer peripheral wall of the transition portion along its axial section is composed of a straight line, a curve, or a combination of a straight line and a curve, and the radial cross-sectional dimension of the transition portion gradually increases in the direction extending from the first connecting end face to the second connecting end face.

[0011] According to one embodiment of the present invention, the main body is configured as a polygonal prism or a cylindrical shape.

[0012] According to one embodiment of the present invention, at least one chip removal groove is formed on the outer peripheral wall of the tool body.

[0013] According to one embodiment of the present invention, the chip removal groove extends from the main body to the transition portion, the second connecting end face is irregularly circular, and the equivalent diameter of the equivalent cross-section of the second connecting end face is D. 等 D max =D 等 The absolute value of the rate of change of radial cross-sectional area at any position along the direction extending from the first connecting end face to the second connecting end face of the transition portion always does not exceed 3 × (D 等 -D min The value shown is greater than zero.

[0014] To solve the above-mentioned technical problems and achieve at least one advantage of the present invention, the present invention provides a tool head, the tool head comprising:

[0015] The tool body includes a main body, an impact head located at one end of the main body, and a transition portion located at the other end of the main body. The transition portion includes at least N transition segments, and N is greater than 3. All the transition segments are connected and distributed along the axial direction of the tool body, and the diameter of each transition segment gradually increases along the direction of extension from the shank to the main body.

[0016] A shank for insertion into an impact electric device, the shank being connected to the end of the transition portion away from the main body, and the shank extending axially along the cutter body;

[0017] The diameter of the end face where the handle connects to the transition portion is D. 柄 ;

[0018] The diameter of the end face where the main body and the transition part connect is D. 主 And D 主>D 柄 ;

[0019] All the aforementioned transition segments are defined sequentially along the direction of extension from the handle to the main body as: segment 1, segment 2, ..., segment N, K = 1, 2, ..., N;

[0020] The diameter of the transition section described in segment K is D. K ;

[0021] The diameter of the transition section described in segment K-1 is D. K-1 When K=1, D K-1 =D 柄 D K Always keep greater than D K-1 ;

[0022] The diameter change rate of the transition section described in segment K is...

[0023] The values ​​shown do not exceed tan4(D) 主 -D 柄 The value is displayed.

[0024] According to one embodiment of the present invention, the outer peripheral wall of the transition portion has a stepped profile along the single side of its axial cross section.

[0025] To solve the above-mentioned technical problems and achieve at least one advantage of the present invention, the present invention provides a tool head, the tool head comprising:

[0026] The tool body includes a main body, an impact head located at one end of the main body, and a transition part located at the other end of the main body. The transition part includes at least two transition sections, and all the transition sections are connected and distributed along the axial direction of the tool body.

[0027] A shank for insertion into an impact electric device, the shank being connected to the end of the transition portion away from the main body, and the shank extending axially along the cutter body, the transition portion having a first connecting end face connected to the shank and a second connecting end face connected to the main body, the area of ​​the second connecting end face being larger than the area of ​​the first connecting end face;

[0028] The diameter of the end face where the handle connects to the transition portion is D. 柄 ;

[0029] The diameter of the end face where the main body and the transition part connect is D. 主 ;

[0030] All the transition segments extending from the handle to the main body are sequentially defined as: segment 1, segment 2, ..., segment n, where n is the total number of transition segments, k = 1, 2, ..., n, and the maximum diameter of each transition segment gradually increases along the direction of extension from the handle to the main body.

[0031] The maximum diameter of the transition section described in segment k is D. k ;

[0032] The maximum diameter of the transition section described in segment k-1 is D. k-1 When k=1, D k-1 =D 柄 ;

[0033] The transition section is divided into a first transition section and a second transition section according to its type. The transition portion includes at least one first transition section and at least one second transition section. The radial cross-sectional dimension of the first transition section gradually increases from one end toward the handle to one end toward the main body in the extending direction, and the radial cross-sectional area change rate of the first transition section at any position in the extending direction always does not exceed 3 × (D). 主 -D 柄 The value shown is greater than zero;

[0034] When the transition segment described in segment k is the second transition segment, the radial cross-sectional area change rate at any position of the transition segment described in segment K is shown to exceed 3 × (D) 主 -D 柄 The value shown is either zero or equal to zero. The rate of change of the diameter of the transition segment described in segment k is: and The values ​​shown do not exceed tan4(D) 主 -D 柄 The value is displayed.

[0035] According to one embodiment of the present invention, the outer peripheral wall of the tool body forms at least one chip removal groove, or the main body is in the shape of a polygonal prism or a cylinder.

[0036] To solve the above-mentioned technical problems and achieve at least one advantage of the present invention, the present invention provides an electric tool, the electric tool comprising:

[0037] The tool head as described in any of the above embodiments;

[0038] An impact electric device, wherein the handle is inserted into the impact electric device.

[0039] Compared with the prior art, the power tool and its tool head provided by the present invention have a smaller reflected wave generated by the shock wave propagating inside the tool head during operation, so as to transfer more energy to the object to be worked, thereby improving the impact efficiency. Attached Figure Description

[0040] Figure 1 shows a schematic diagram of the structure of an existing tool head.

[0041] Figure 2 shows a schematic diagram of an example of the first embodiment of the tool head of the present invention.

[0042] Figure 3 shows a schematic diagram of the structure of the first example of the first embodiment of the tool head of the present invention.

[0043] Figure 4 shows a structural schematic diagram of a second example of the first embodiment of the tool head of the present invention.

[0044] Figure 5 shows a structural schematic diagram of the third example of the first embodiment of the tool head of the present invention.

[0045] Figure 6 shows a cross-sectional view of the tool head described in this invention from one perspective.

[0046] Figure 7 shows a schematic diagram of the structure of the second embodiment of the tool head of the present invention.

[0047] Figure 8 shows a schematic diagram of an example of the third embodiment of the tool head of the present invention.

[0048] Figure 9 shows a structural schematic diagram of yet another example of the third embodiment of the tool head described in this invention.

[0049] Figure 10 shows a structural schematic diagram of an embodiment of the power tool described in this invention.

[0050] Figure 11 shows a schematic diagram of another embodiment of the power tool described in this invention. Detailed Implementation

[0051] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0052] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0053] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0054] Referring to Figures 2 to 9, a tool head according to a preferred embodiment of the present invention will be described in detail below. The tool head includes a tool body 10 and a shank 20. The tool body 10 includes a main body 11, an impact head 12 located at one end of the main body 11, and a transition portion 13 located at the other end of the main body 11. The shank 20 is connected to the end of the transition portion 13 away from the main body 11, and the shank 20 extends axially along the tool body 10.

[0055] Referring to Figures 10 and 11, the shank 20 of the tool head is inserted into the impact electric device 900, forming a power tool. Preferably, the shank 20 of the tool head is detachably mounted to the impact electric device 900. After the tool head is mounted to the impact electric device 900, it can be driven by the drive unit of the impact electric device 900, so that the impact head 12 and the main body 11 can impact the object to be worked, thereby forming a hole or breaking the object after the tool head is withdrawn from it.

[0056] In one embodiment, at least one chip removal groove 101 is formed on the outer peripheral wall of the tool body 10 between the two ends of the tool body 10, as shown in FIG10. Specifically, the chip removal groove 101 is provided extending from the end of the impact head 12 to the main body portion 11. Preferably, the chip removal groove 101 is a spiral groove provided between the two ends of the tool body 10.

[0057] Furthermore, referring to FIG11, the main body 11 is deformably shaped as a polygonal prism or a cylinder.

[0058] It is worth mentioning that the cross-section formed by the end of the transition portion 13 connected to the handle portion 20 is defined as the first connecting end face, while the cross-section formed by the other end of the transition portion 13 connected to the main body portion 11 is defined as the second connecting end face. The size of the second connecting end face is larger than the size of the first connecting end face (neither the first connecting end face nor the second connecting end face is shown in the figures).

[0059] The diameter of the first connecting end face is denoted as D. min ;

[0060] The diameter of the second connecting end face is denoted as D. max ;

[0061] The diameter of the end face where the handle 20 connects to the first connecting end face is denoted as D. 柄 ;

[0062] The diameter of the end face where the main body 11 connects to the second connecting end face is denoted as D. 主 .

[0063] In the first embodiment, referring to Figures 2 to 6, the absolute value of the rate of change of radial cross-sectional area of ​​the transition portion 13 at any position in the direction extending from the first connecting end face to the second connecting end face never exceeds 3 × (D max -D min The value shown is greater than zero, and the rate of change of the radial cross-sectional area of ​​the transition section 13 satisfies 3×(D). max -D min Furthermore, a tool head with a value greater than zero can significantly improve the efficiency of hole drilling.

[0064] In a first example of the first embodiment, referring to Figures 2 to 4, the radial cross-sectional dimension of the transition portion 13 gradually increases in the direction extending from the first connecting end face to the second connecting end face. The single-sided profile of the outer peripheral wall of the transition portion 13 in its axial cross-section is a straight line, a curve, or a combination of a straight line and a curve. The rate of change of cross-sectional area of ​​the transition portion 13 at any position in the extending direction is shown to be no more than 3 × (D). max -D min The value shown is greater than zero, and the smaller the value, the smoother the transition of the transition section 13 from the handle 20 to the main body 11, and the higher the work efficiency.

[0065] In the second example of the first embodiment, referring to Figures 5 and 6, when at least one chip removal groove 101 is formed on the outer peripheral wall of the tool body 10, and the chip removal groove 101 extends from the main body portion 11 to the second connecting end face of the transition portion 13, the cross-sectional profile of the second connecting end face is irregularly circular due to the presence of the chip removal groove 101. The equivalent diameter D of the second connecting end face can be calculated based on its equivalent cross-section. 等 At this time, D max =D 等 The absolute value of the rate of change of radial cross-sectional area at any position along the extension direction from the first connecting end face to the second connecting end face of the transition section 13 always does not exceed 3 × (D 等 -D min The value is shown as greater than zero.

[0066] It is worth mentioning that, since the cross-sectional profile of the second connecting end face is an irregular circle, the radial cross-sectional area change rate of part of the transition portion 13 in the extension direction will be less than zero. Therefore, in the modified example, the absolute value of the radial cross-sectional area change rate and 3×(D) need to be used. 等 -D min The text shows the numerical values ​​and compares them with zero.

[0067] Referring to Figures 2 and 4, the design of the first example of the first embodiment is applied to φ22, D max =18.9mm and D min Taking a 10mm drill bit as an example, the maximum radial cross-sectional change rate of the transition section 13 was adjusted, and the drill bit with each maximum radial cross-sectional change rate was used to drill five holes consecutively for testing. The data obtained are shown below:

[0068] In the table above, the tool head with a maximum radial cross-sectional area change rate of 49.9 is greater than 3 × (D). max -D min The figures are shown, and the hole-opening efficiency improvement is only 7.29%, lower than 10.58%, and therefore not within the scope defined by this invention. A tool head with a maximum radial cross-sectional area change rate of 26.7 is equal to 3 × (D) max -D min The values ​​shown indicate that the hole-opening efficiency has increased by 10.58%. Therefore, the maximum radial cross-sectional area change rate of the tool head can be taken as the maximum value of this example, which means that the tool head with a maximum radial cross-sectional area change rate greater than zero and less than or equal to 26.7 can achieve a hole-opening efficiency increase of 10.58% or more.

[0069] In the second embodiment, referring to FIG7, the transition portion 13 includes at least N transition segments 131 (where N is greater than 3). All the transition segments 131 are connected and distributed along the axial direction of the tool body 10. One transition segment 131 is connected to the shank 20, and the transition segment 131 connected to the shank 20 forms the first connecting end face; another transition segment 131 is connected to the main body 11, and the transition segment 131 connected to the main body 11 forms the second connecting end face. The diameter of each transition segment 131 gradually increases along the direction of extension from the shank 20 to the main body 11.

[0070] All the transition segments 131 extending from the handle 20 toward the main body 11 are sequentially defined as: segment 1, segment 2, ..., segment N. The diameter of the transition segment 131 in segment K is D. K (K = 1, 2, ..., N); the diameter of the transition segment 131 described in segment K-1 is D. K-1 When K=1, DK-1 =D 柄 .

[0071] The diameter change rate of the transition segment 131 described in segment K is: in The calculated value does not exceed tan4(D) 主 -D 柄 The calculated value.

[0072] In a preferred embodiment, the outer peripheral wall of the transition portion 13 has a stepped profile on its own axial cross section.

[0073] It is worth mentioning that the more transition segments 131 there are, and the smaller the diameter difference between two adjacent transition segments 131, the more the second embodiment can be approximated as the first example in the first embodiment, and the higher the working efficiency of the tool head will be. The working efficiency of the tool head designed in this embodiment is 10.58% or more higher than that of the existing tool head.

[0074] In the third embodiment, referring to Figures 8 and 9, the transition portion 13 includes at least two transition segments 131A. All the transition segments 131A are connected and distributed along the axial direction of the tool body 10. One transition segment 131A is connected to the shank 20, and the transition segment 131A connected to the shank 20 forms the first connection end face; the other transition segment 131A is connected to the main body 11, and the transition segment 131A connected to the main body 11 forms the second connection end face.

[0075] All the transition segments 131A extending from the handle 20 toward the main body 11 are sequentially defined as: segment 1, segment 2, ..., segment n, where n is the total number of transition segments 131A. The maximum diameter of the k-th transition segment 131A is D. k (k = 1, 2, ..., n); the maximum diameter of the transition segment 131 described in the (k-1)th segment is D. k-1 When k=1, D k-1 =D 柄 .

[0076] The transition section 131A can be divided into a first transition section 1311A and a second transition section 1312A according to its type. The transition portion 13 includes at least one first transition section 1311A and at least one second transition section 1312A. The radial cross-sectional dimension of the first transition section 1311A gradually increases in the extending direction from one end face toward the handle portion 20 to one end face toward the main body portion 11, and the value of the radial cross-sectional area change rate at any position in the extending direction never exceeds 3×(D). 主 -D 柄The value is shown as greater than zero.

[0077] When the transition segment 131A of the k-th segment is the second transition segment 1312A, the rate of change of the radial cross-sectional area of ​​this segment at any position in the extension direction shows a value exceeding 3 × (D 主 -D 柄 The value is either zero or equal to zero, and the rate of change of the diameter of the segment is: in The calculated value does not exceed tan4(D) 主 -D 柄 The calculated value.

[0078] It is understood that, in this embodiment, the value of the radial cross-sectional area change rate of the first transition segment 1311A never exceeds 3 × (D 主 -D 柄 The value shown is greater than zero, and its principle is the same as the first example of the first embodiment; the diameter change rate of the second transition segment 1312A does not exceed tan4(D) 主 -D 柄 The calculated values ​​are based on the same principle as in the second embodiment, and will not be described further here. The working efficiency of the tool head designed in this embodiment is 10.58% or more higher than that of existing tool heads.

[0079] It is worth mentioning that the above-mentioned design of the present invention is applicable to both drill bits and chisels, and the shank 20 of the tool head can be set to any shape such as round, square, five-hole, and hexagonal. In other words, the above-mentioned design is applicable to any form of tool head such as round shank drill bits, round shank chisels, square shank drill bits, square shank chisels, five-hole drill bits, five-hole chisels, hexagonal drill bits, and hexagonal chisels.

[0080] In existing tool heads, the transition portion 13A is designed as a single cylinder, and the radial cross-sectional dimension of the end face of the transition portion 13A facing the shank 20A is abruptly larger than that of the shank 20A facing the transition portion 13A. When the power tool is running, the impact rod provided by the impact electric device 900 transmits impact force to the tool head. This impact force propagates in the form of waves inside the tool head. A large number of shock waves are transmitted sequentially through the shank 20A, transition portion 13A, main body 11A, and impact head 12A to the workpiece. However, some shock waves are reflected after passing through the transition portion 13A, and this energy is not utilized, thus reducing the impact efficiency of the tool head. In this invention, because the radial cross-sectional dimension of the transition portion 13 increases gradually, the reflected wave generated inside the tool head when the shock wave propagates is smaller. Therefore, the tool head can transfer more energy to the workpiece, thereby improving the impact efficiency.

[0081] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments; any variations or modifications can be made to the implementation of the present invention without departing from these principles.

Claims

1. A tool head, characterized in that, The tool head includes: The tool body includes a main body, an impact head located at one end of the main body, and a transition part located at the other end of the main body; A shank for insertion into an impact electric device, the shank being connected to the end of the transition portion away from the main body, and the shank extending axially along the cutter body, the transition portion having a first connecting end face connected to the shank and a second connecting end face connected to the main body, the area of ​​the second connecting end face being larger than the area of ​​the first connecting end face; The diameter of the first connecting end face is D. min ; The diameter of the second connecting end face is D max ; The absolute value of the rate of change of radial cross-sectional area at any position along the direction extending from the first connecting end face to the second connecting end face of the transition section never exceeds 3 × (D). max -D min The value is shown as greater than zero.

2. The tool head according to claim 1, characterized in that, The outer peripheral wall of the transition section is composed of a straight line, a curve, or a combination of straight lines and curves along its axial cross-section, and the radial cross-sectional dimension of the transition section gradually increases from the first connecting end face to the second connecting end face.

3. The tool head according to claim 2, characterized in that, The main body is configured as a polygonal prism or a cylindrical shape.

4. The tool head according to claim 2, characterized in that, At least one chip removal groove is formed on the outer peripheral wall of the tool body.

5. The tool head according to claim 4, characterized in that, The chip removal groove extends from the main body to the transition portion, and the second connecting end face is an irregular circle. The equivalent diameter of the equivalent cross-section of the second connecting end face is D. 等 D max =D 等 The absolute value of the rate of change of radial cross-sectional area at any position along the direction extending from the first connecting end face to the second connecting end face of the transition portion always does not exceed 3 × (D 等 -D min The value shown is greater than zero.

6. A tool head, characterized in that, The tool head includes: The tool body includes a main body, an impact head located at one end of the main body, and a transition portion located at the other end of the main body. The transition portion includes at least N transition segments, and N is greater than 3. All the transition segments are connected and distributed along the axial direction of the tool body, and the diameter of each transition segment gradually increases along the direction of extension from the shank to the main body. A shank for insertion into an impact electric device, the shank being connected to the end of the transition portion away from the main body, and the shank extending axially along the cutter body; The diameter of the end face where the handle connects to the transition portion is D. 柄 ; The diameter of the end face where the main body and the transition part connect is D. 主 And D 主 >D 柄 ; All the aforementioned transition segments are defined sequentially along the direction of extension from the handle to the main body as: segment 1, segment 2, ..., segment N, K = 1, 2, ..., N; The diameter of the transition section described in segment K is D. K ; The diameter of the transition section described in segment K-1 is D. K-1 When K=1, D K-1 =D 柄 D K Always keep greater than D K-1 ; The diameter change rate of the transition section described in segment K is... The values ​​shown do not exceed tan4(D) 主 -D 柄 The value is displayed.

7. The tool head according to claim 6, characterized in that, The outer peripheral wall of the transition section is stepped along the single-sided profile of its axial section.

8. A tool head, characterized in that, The tool head includes: The tool body includes a main body, an impact head located at one end of the main body, and a transition part located at the other end of the main body. The transition part includes at least two transition sections, and all the transition sections are connected and distributed along the axial direction of the tool body. A shank for insertion into an impact electric device, the shank being connected to the end of the transition portion away from the main body, and the shank extending axially along the cutter body, the transition portion having a first connecting end face connected to the shank and a second connecting end face connected to the main body, the area of ​​the second connecting end face being larger than the area of ​​the first connecting end face; The diameter of the end face where the handle connects to the transition portion is D. 柄 ; The diameter of the end face where the main body and the transition part connect is D. 主 ; All the transition segments extending from the handle to the main body are sequentially defined as: segment 1, segment 2, ..., segment n, where n is the total number of transition segments, k = 1, 2, ..., n, and the maximum diameter of each transition segment gradually increases along the direction of extension from the handle to the main body. The maximum diameter of the transition section described in segment k is D. k ; The maximum diameter of the transition section described in segment k-1 is D. k-1 When k=1, D k-1 =D 柄 ; The transition section is divided into a first transition section and a second transition section according to its type. The transition portion includes at least one first transition section and at least one second transition section. The radial cross-sectional dimension of the first transition section gradually increases from one end toward the handle to one end toward the main body in the extending direction, and the radial cross-sectional area change rate of the first transition section at any position in the extending direction always does not exceed 3 × (D). 主 -D 柄 The value shown is greater than zero; When the transition segment described in segment k is the second transition segment, the radial cross-sectional area change rate at any position of the transition segment described in segment K is shown to exceed 3 × (D) 主 -D 柄 The value shown is either zero or equal to zero. The rate of change of the diameter of the transition segment described in segment k is: and The values ​​shown do not exceed tan4(D) 主 -D 柄 The value is displayed.

9. The tool head according to claim 8, characterized in that, The outer peripheral wall of the tool body forms at least one chip removal groove, or the main body is in the shape of a polygonal prism or a cylinder.

10. A power tool, characterized in that, The power tool includes: The tool head as described in any one of claims 1 to 9; An impact electric device, wherein the handle is inserted into the impact electric device.