Impact tool

Abstract

The application discloses an impact tool, comprising: an impact assembly for providing an impact force; the impact assembly further comprises: a ball arranged in a first ball groove on an impact block and a second ball groove on a main shaft, so as to connect the impact block and the main shaft; the impact block comprises a first position of a farthest end of forward movement; when the impact block moves to the first position, the ball has a second spacing with a front edge of the second ball groove in a direction along an axis of the main shaft; during working of the impact tool, a distance from a ball center of the ball to the second ball groove in a direction perpendicular to the axis of the main shaft is L1, and a diameter D1 of the ball is less than or equal to 95% of L1. The application outputs high impact frequency and large impact force.

Description

Technical Field

[0001] This application relates to a power tool, specifically an impact tool. Background Technology

[0002] Currently, impact tools on the market mainly include impact screwdrivers and impact wrenches used for driving screws. Impact screwdrivers operate at high speeds, requiring high initial rotational speed and a high impact frequency. Impact wrenches, on the other hand, output high torque, requiring a high impact force from the impact system.

[0003] Whether it's requiring high impact frequency or providing large impact force, as users' demands for the performance of impact tools increase, they are placing higher demands on the performance of the impact systems of these tools.

[0004] Therefore, further improving the performance of impact systems has become a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0005] The purpose of this application is to provide an impact tool that solves the problem of jamming in impact systems under conditions of high impact frequency and large impact force output.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] An impact tool includes: a motor, including a motor shaft rotatable about a first axis; an output assembly, including an output shaft centered on an output axis for outputting power; an impact assembly for providing impact force; a main shaft driven by the motor shaft and an impact block sleeved on the main shaft; the main shaft rotates about its axis; the impact assembly further includes: a ball spanning a first ball groove on the impact block and a second ball groove on the main shaft, connecting the impact block and the main shaft; the impact block includes a first position at its farthest forward movement; when the impact block moves to the first position, the ball has a second distance from the front edge of the second ball groove along the main shaft axis; during operation of the impact tool, in a direction perpendicular to the main shaft axis, the distance from the center of the first ball groove to the second ball groove is L1, and the diameter D1 of the ball is less than or equal to 95% of L1.

[0008] In some embodiments, the diameter D1 of the rolling ball is greater than or equal to 72% of L1.

[0009] In some embodiments, when the impact block moves to the first position, the rolling ball and the rear edge of the second ball groove have a third distance along the direction of the main shaft axis, and the third distance is greater than or equal to the second distance.

[0010] In some embodiments, when the impact block moves to the first position, the rolling ball has a first distance from the rear edge of the first ball groove along the direction of the main shaft axis.

[0011] In some embodiments, when the impact block moves to the first position, the outer surface of the ball has a first contact point with the first ball groove, and the outer surface of the ball has a second contact point with the second ball groove.

[0012] In some embodiments, the first contact point and the center of the rolling ball form a first line, and the second contact point and the center of the rolling ball form a second line, wherein the first line and the second line are collinear.

[0013] In some embodiments, the first contact point and the center of the rolling ball form a first line, and the second contact point and the center of the rolling ball form a second line, wherein the angle β between the first line and the second line is an obtuse angle.

[0014] In some embodiments, the first ball groove has a semi-circular groove bottom with radius R1, and the second ball groove has a semi-circular groove bottom with radius R2, wherein R1+R2>L1 in the direction perpendicular to the main shaft axis.

[0015] In some embodiments, the impact assembly further includes an anvil disposed at the front end of the impact block, wherein a first position of the impact block is engaged on the anvil.

[0016] In some embodiments, the impact assembly further includes: an elastic element that provides a force to the impact block to bring it closer to the anvil; the elastic element is disposed between the spindle and the impact block.

[0017] In some embodiments, at least two of each of the rolling ball, the first ball groove, and the second ball groove are provided.

[0018] This application provides an impact tool. When the impact block is in a first position, a second distance is provided between the rolling ball and the front edge of the second ball groove along the first axis direction, so that the contact point between the rolling ball and the second ball groove is not at the edge of the second ball groove. By setting the contact point between the rolling ball and the second ball groove on the side wall of the second ball groove, deformation of the second ball groove can be effectively prevented. By controlling the relationship between the distance L1 from the center of the rolling ball to the second ball groove in the direction perpendicular to the first axis and the diameter of the rolling ball, the compression of the rolling ball by the impact ball track is reduced, and the problem of the rolling ball getting stuck during the impact process is improved. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the first embodiment in this application;

[0020] Figure 2 yes Figure 1 A schematic diagram of the exploded view of the middle section of the structure;

[0021] Figure 3 yes Figure 1 A schematic diagram of a cross-sectional view when the impact block is in the second position;

[0022] Figure 4 yes Figure 1 A schematic diagram of a cross-sectional view when the impact block is in the first position;

[0023] Figure 5 yes Figure 4 A magnified view of part A in the middle, where R1=R2;

[0024] Figure 6 yes Figure 4 A magnified view of part A in the middle, where R1 > R2;

[0025] Figure 7 yes Figure 4 A magnified view of part A in the image, where R1 < R2. Detailed Implementation

[0026] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] To clearly illustrate the technical solution of this application, the following are also defined: Figures 1-4 The top, bottom, front, and back sides are shown.

[0030] like Figure 1 An impact tool according to a first embodiment of this application is shown; the power tool is an impact wrench 100. It will be understood that in other alternative embodiments, the impact tool can be equipped with different working attachments, allowing the impact tool to be, for example, an impact drill, an impact screwdriver, etc.

[0031] like Figures 1 to 7 An impact wrench 100 according to a first embodiment of this application is shown, including a power supply device 30. The power supply device 30 provides electrical energy to the impact wrench 100. In this embodiment, the power supply device 30 is a battery pack, which, in conjunction with a corresponding power circuit, supplies power to corresponding components within the drill 100. Those skilled in the art should understand that the power supply device 30 is not limited to scenarios using a battery pack; it can also supply power to corresponding components within the machine via mains power or AC power, in conjunction with corresponding rectification, filtering, and voltage regulation circuits.

[0032] The impact wrench 100 includes a housing 11, a motor 12, a transmission assembly 13, an impact assembly 14, and an output assembly 15. The housing 11 includes a motor housing 111 for housing the motor 12 and an output housing 112 for housing at least a portion of the output assembly 15. The output housing 112 is connected to the front end of the motor housing 111. The housing 11 also forms or is connected to a grip portion 113 for user operation. The grip portion 113 and the motor housing 111 form a T-shaped or L-shaped structure for easy gripping and operation. One end of the grip portion 113 is connected to a power supply device 30. The power supply device 30 is detachably connected to the grip portion 113. The motor 12, transmission assembly 13, impact assembly 14, and output assembly 15 are arranged sequentially in the front-rear direction within the motor housing 111 and the output housing 112.

[0033] The motor 12 includes a motor shaft capable of rotating about a first axis 101. The output assembly 15 includes an output shaft 151 for connecting and driving a working attachment to rotate. The front end of the output shaft 151 is provided with a clamping assembly or receiving part, which can clamp the corresponding working attachment, such as a screwdriver, drill bit, socket, etc., when performing different functions.

[0034] The output shaft 151 is used to output power. The output shaft 151 rotates about an output axis, which in this embodiment is the second axis 102. In this embodiment, the first axis 101 and the second axis 102 coincide. In other alternative embodiments, the second axis 102 and the first axis 101 are set at a certain angle. In other alternative embodiments, the first axis 101 and the second axis 102 are parallel to each other but do not coincide.

[0035] Impact assembly 14 is used to provide impact force to output shaft 151. Transmission assembly 13 is disposed between motor 12 and impact assembly 14 to transmit power between motor 12 and impact assembly 14. In this embodiment, transmission assembly 13 is a reduction gear system.

[0036] The impact assembly 14 includes a main shaft 18, an impact block 19 sleeved around the outer periphery of the main shaft 18, a hammer anvil 141 disposed at the front end of the impact block 19, and an elastic element 144. The hammer anvil 141 includes an anvil seat 142 and an output shaft 151. The impact block 19 is driven by the main shaft 18, the anvil seat 142 engages with the impact block 19 and is struck by it, and the anvil seat 142 drives the output shaft 151 to rotate. The impact block 19 includes an impact block body 191, and a pair of first end teeth 196 are radially symmetrically protruded from the front end face of the impact block body 191; a pair of second end teeth 143 are radially symmetrically protruded from the rear end face of the anvil seat 142 opposite to the impact block 19. The output shaft 151 extends out of the output housing 112; the output shaft 151 is connected to the anvil seat 142. It is understood that the anvil seat 142 and the output shaft 151 can be integrally formed or separately formed independent parts. The impact block 19 is supported on the main shaft 18 and can reciprocate relative to the main shaft 18 in the front-rear direction. The elastic element 144 provides the impact block 19 with a force that brings it closer to the anvil 141.

[0037] During operation of the impact wrench 100, the impact block 19 reciprocates relative to the main shaft 18 along the main shaft axis 103 with a predetermined stroke. In this embodiment, the main shaft axis 103 coincides with the first axis 101. The impact block 19 includes a first position where it moves forward to its farthest point and a second position where it moves backward to its farthest point. In the first position, the first end tooth 196 of the impact block 19 engages with the hammer anvil 141, meaning that the front end of the stroke of the impact block 19 is stopped by the hammer anvil 141. Figure 3 The impact block 19 is shown in the second position. Figure 4 The impact block 19 is shown in the first position.

[0038] The front end face of the impact block body 191 is also provided with a pair of first ball grooves 192 with openings facing forward and extending backward in the front-rear direction. The outer surface of the main shaft 18 is also formed with a pair of V-shaped second ball grooves 181. The first ball grooves 192 and the second ball grooves 181 have semi-circular groove bottoms.

[0039] The impact assembly 14 also includes a ball 17. The ball 17 spans the first ball groove 192 and the second ball groove 181, thereby connecting the impact block 19 to the main shaft 18. In this embodiment, the ball 17 is a steel ball.

[0040] The following describes the working process of the impact wrench 100. When the main shaft 18 rotates, the movement of the ball bearing 17 within the second ball groove 181 allows the impact block 19 to move relative to the main shaft 18 in the front-to-back direction. Specifically, when the impact wrench 100 is unloaded or lightly loaded, the impact assembly 14 does not impact; instead, it acts as a transmission mechanism. The impact block 19 is in the first position, and the rotation of the motor shaft 12 is transmitted to the main shaft 18 via the transmission assembly 13, causing the main shaft 18 to rotate. Since the main shaft 18 rotates the impact block 19 using the ball bearing 17, and the first end tooth 196 of the impact block 19 engages with the second end tooth 143 of the anvil 142, the hammer anvil 141 rotates, thus causing the output shaft 151 and the working head mounted on the output shaft 151 to rotate. When the impact wrench 100 is subjected to a load, the rotation of the output shaft 151 is hindered. Due to varying load sizes, the output shaft 151 cannot rotate with the main shaft 18; its speed may decrease or it may stop rotating completely. However, as the main shaft 18 continues to rotate, the rolling ball 17 located at the rear end of the first ball groove 192 will roll backward along the second ball groove 181 of the main shaft 18, thereby causing the impact block 19 to move backward along the main shaft axis 103, that is, to move to the second position of the impact block 19. At the same time, the impact block 19 squeezes the elastic element 144 until the impact block 19 is completely disengaged from the hammer anvil 141, at which point the impact block 19 is in the second position. The elastic element 144 rebounds along the main shaft axis 103 to apply force to the impact block 19. The ball 17 rolls along the second ball groove 181, thus moving forward while rotating. At this time, the relative rotation speed between the impact block 19 and the hammer anvil 141 is the rotation speed of the impact block 19. When the impact block 19 rotates to contact the hammer anvil 141, it will apply an impact force to the hammer anvil 141. Under the action of this impact force, the output shaft 151 continues to rotate at a certain angle to overcome the load. Then the output shaft 151 stops rotating again. The above process is repeated to realize that the impact block 19 intermittently applies rotational striking force to increase the output force.

[0041] During the rolling of the ball 17 between the first ball groove 192 and the second ball groove 181, a lubricant is used between the ball 17 and the first ball groove 192 and the second ball groove 181 to increase smoothness. When the impact frequency of the impact assembly 14 increases, the sliding speed of the impact block 19 increases, causing heat to be generated inside the impact assembly 14. The higher the impact frequency, the higher the heat generated inside the impact assembly 14. This heat can cause the lubricant to deteriorate, especially when the lubricant is lubricating oil, which can deteriorate into sludge-like substances. Sludge-like substances tend to accumulate and can block the smooth movement between the ball 17 and the ball groove. This is one reason affecting the impact performance of the impact wrench 100.

[0042] When the impact block 19 rotates to contact the anvil 141, that is, when the impact block 19 strikes the anvil 141, whether increasing the K value of the elastic element 144 or increasing the mass of the impact block 19, the purpose is to increase the impact force of the impact block 19 striking the anvil 141. Figure 4-5 As shown, when the impact block 19 is in the first position, i.e., when the impact block 19 strikes the anvil 141, the ball 17 also applies pressure to the second ball groove 181 located on the main shaft 18. In the prior art, the second ball groove 181 on the main shaft 18 is provided with a semi-circular groove bottom, the width of which is greater than the diameter of the ball 17. Furthermore, the radius R2 of the semi-circular groove bottom is greater than the radius of the ball 17. Therefore, theoretically, the ball 17 is in contact with the wall of the second ball groove 181 at one point. In the prior art, as the output impact force increases, the pressure applied by the ball 17 to the second ball groove 181 also increases. Often, the second ball groove 181 of the main shaft 18 deforms due to the increased force, causing the ball 17 to become stuck during the impact, resulting in the impact failure of the impact assembly 14. This is another reason affecting the impact performance of the impact wrench 100.

[0043] In this application, the applicant discovered through research that the two factors affecting the impact performance of the impact wrench 100, which can be addressed by increasing the hardness of the spindle 18 and improving the performance of the lubricant, would increase the product cost of the impact wrench 100. Moreover, through dimensional chain calculations and motion simulation analysis, the essential solution lies in the design dimensions and positions of the first ball groove 192, the second ball groove 181, and the rolling ball 17.

[0044] like Figure 4-5 As shown, in this embodiment, when the impact block 19 is in the first position, a second distance G2 is provided between the rolling ball 17 and the front edge of the second ball groove 181 along the first axis 101. That is, the contact point between the rolling ball 17 and the second ball groove 181 is not the edge of the second ball groove. Since the edge of the second ball groove 181 is a stress concentration point and its strength is relatively weak, when the contact point between the rolling ball 17 and the second ball groove 181 is located at the edge of the second ball groove 181, the second ball groove 181 is most likely to deform due to the force of bearing the rolling ball 17. Setting the contact point between the rolling ball 17 and the second ball groove 181 on the side wall of the second ball groove 181, that is, the rolling ball 17 and the front edge of the second ball groove 181 have a distance, can effectively prevent the deformation of the second ball groove 181.

[0045] During the operation of the impact wrench 100, the ball 17 is always positioned between the first ball groove 192 and the second ball groove 181. In this embodiment, taking the impact block 19 in the first position as an example, in the direction perpendicular to the first axis 101 (vertical direction in this embodiment), the distance from the first ball groove 192 through the ball center 171 to the second ball groove 181 is L1, and the diameter D1 of the ball 17 is less than or equal to 95% of L1. It can be understood that L1 is the width of the impact track formed by the first ball groove 192 and the second ball groove 181 that accommodates the ball 17. The ball 17 rolls within the impact track of width L1 while simultaneously moving along the path of the impact track. When L1 is too small, in this embodiment, when the diameter D1 of the ball 17 is greater than 95% of the impact track width L1, if the lubricating material deteriorates, the ball 17 cannot overcome these impurities, thus causing the ball 17 to become stuck. Meanwhile, when the diameter D1 of the ball 17 is greater than 95% of the width L1 of the impact track, the gap between the impact track and the ball 17 is too small, which will cause the impact track to squeeze the ball 17, exacerbating the heat dissipation problem of the impact system. Furthermore, increasing the gap between the impact track and the ball 17 will reduce the difficulty of component manufacturing and assembly.

[0046] Furthermore, the diameter D1 of the rolling ball 17 is less than or equal to 92% of L1. Even further, the diameter D1 of the rolling ball 17 is less than or equal to 90% of L1.

[0047] To ensure the reliability of the impact assembly 14 in providing impact and to achieve product miniaturization, the diameter of the ball 17 is greater than or equal to 72% of L1.

[0048] In this embodiment, when the impact block 19 is in the first position, the rolling ball 17 and the rear edge of the first ball groove 192 have a first distance G1 along the direction of the main shaft axis 103. The rolling ball 17 and the rear edge of the second ball groove 181 have a third distance G3, wherein the third distance G3 is greater than or equal to the second distance G2.

[0049] As described above, the rolling ball 17 theoretically abuts against the wall of the second ball groove 181 at one contact point. Similarly, the first ball groove 192 on the impact block 19 is also provided with a semi-circular groove bottom, the width of which is greater than the diameter of the rolling ball 17. Therefore, the rolling ball 17 theoretically abuts against the wall of the first ball groove 192 at one contact point.

[0050] In this embodiment, when the impact block 19 moves to the first position, the outer surface of the rolling ball 17 has a first contact point 193 with the first ball groove 192, and the outer surface of the rolling ball 17 has a second contact point 182 with the second ball groove 181. It can be understood that in the design curves of the rolling ball 17, the first ball groove 192, and the second ball groove 181, the first tangent point between the rolling ball 17 and the first ball groove 192 is the first contact point 193, and the second tangent point between the rolling ball 17 and the second ball groove 181 is the second contact point 182. The second contact point 182 is not located on the edge of the second ball groove 181. In this embodiment, the first contact point 193 is also not located on the edge of the first ball groove 192.

[0051] The dimensions of the first ball groove 192 and the second ball groove 181 in this embodiment are further described. The radius of the semi-circular bottom of the first ball groove 192 is R1. The radius of the semi-circular bottom of the second ball groove 181 is R2. Since both the first contact point 193 and the second contact point 182 are located at non-edge positions of the semi-circular bottom of the groove, in a direction perpendicular to the first axis 101, R1 + R2 > L1. The diameter D1 of the rolling ball 17 is less than or equal to 2*R2 or 91% of 2*R1. Furthermore, in the direction of the first axis 101, the center 194 of the semi-circular bottom of the first ball groove 192 is not collinear with the center 171 of the rolling ball, and the center 183 of the semi-circular bottom of the second ball groove 181 is not collinear with the center 171 of the rolling ball. Furthermore, in the direction perpendicular to the first axis 101, the center 194 of the semi-circular bottom of the first ball groove 192 is not collinear with the center 171 of the rolling ball, and the center 183 of the semi-circular bottom of the second ball groove 181 is not collinear with the center 171 of the rolling ball.

[0052] like Figure 4-5 As shown, in this embodiment, R1=R2, the first contact point 193 and the center of the rolling ball 171 form a first connecting line 195, and the second contact point 182 and the center of the rolling ball 171 form a second connecting line 184, wherein the first connecting line 195 and the second connecting line 184 are collinear.

[0053] In other alternative embodiments, such as Figure 6 and 7 As shown, this applies when R1≠R2. Specifically, as... Figure 6 As shown, when R1 > R2, the first contact point 193a and the center of the rolling ball 171 form a first connecting line 195a. The second contact point 182a and the center of the rolling ball 171 form a second connecting line 184a. An angle β is formed between the first connecting line 195a and the second connecting line 184a, and this angle β is obtuse. A first straight line is provided passing through the center of the rolling ball 171 in the vertical direction. The angle between the first connecting line 195a and the first straight line is acute, and the angle between the second connecting line 184a and the first straight line is also acute. Where D1 is less than or equal to 91% of 2*R1.

[0054] like Figure 7 As shown, when R1 < R2, the first contact point 193b and the center of the rolling ball 171 form a first connecting line 195b. The second contact point 182b and the center of the rolling ball 171 form a second connecting line 184b. An angle β is formed between the first connecting line 195b and the second connecting line 184b, and this angle β is obtuse. A first straight line is provided passing through the center of the rolling ball 171 in the vertical direction. The angle between the first connecting line 195b and the first straight line is acute, and the angle between the second connecting line 184b and the first straight line is also acute. When R1 < R2, D1 is less than or equal to 91% of 2*R2. This ensures the gap between the width L1 of the impact track and the diameter D1 of the rolling ball 17.

[0055] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. An impact tool, comprising: An electric motor, including a motor shaft capable of rotating about a first axis; Output components, including an output shaft centered on the output axis, are used to output power; An impact assembly for providing impact force; comprising a main shaft driven by the motor shaft and an impact block sleeved on the main shaft; the main shaft rotates about its axis. Its features are, The impact assembly also includes: A rolling ball spans the first ball groove provided on the impact block and the second ball groove provided on the main shaft, thereby connecting the impact block and the main shaft; The impact block includes a first position at its farthest point that moves forward; When the impact block moves to the first position, along the direction of the main shaft axis, the rolling ball and the front edge of the second ball groove have a second distance, and the contact point between the rolling ball and the second ball groove is not the edge of the second ball groove; when the impact block moves to the first position, along the direction of the main shaft axis, the rolling ball and the rear edge of the first ball groove have a first distance. During the operation of the impact tool, in the direction perpendicular to the spindle axis, the distance from the first ball groove through the center of the rolling ball to the second ball groove is L1, and the diameter D1 of the rolling ball is less than or equal to 95% of L1.

2. The impact tool according to claim 1, characterized in that, The diameter D1 of the rolling ball is greater than or equal to 72% of L1.

3. The impact tool according to claim 1, characterized in that, When the impact block moves to the first position, along the direction of the main shaft axis, the rolling ball and the rear edge of the second ball groove have a third distance, the third distance being greater than or equal to the second distance.

4. The impact tool according to claim 1, characterized in that, When the impact block moves to the first position, the outer surface of the ball has a first contact point with the first ball groove, and the outer surface of the ball has a second contact point with the second ball groove.

5. The impact tool according to claim 4, characterized in that, The first contact point and the center of the rolling ball form a first line, and the second contact point and the center of the rolling ball form a second line, wherein the first line and the second line are collinear.

6. The impact tool according to claim 4, characterized in that, The first contact point and the center of the rolling ball form a first line, and the second contact point and the center of the rolling ball form a second line, wherein the angle β between the first line and the second line is an obtuse angle.

7. The impact tool according to claim 1, characterized in that, The first ball groove has a semi-circular bottom with radius R1, and the second ball groove has a semi-circular bottom with radius R2, where R1+R2>L1.

8. The impact tool according to claim 1, characterized in that, The impact assembly also includes a hammer anvil disposed at the front end of the impact block, which locks onto the hammer anvil when the impact block moves to the first position.

9. The impact tool according to claim 8, characterized in that, The impact assembly further includes an elastic element that provides a force to the impact block to bring it closer to the anvil; the elastic element is disposed between the spindle and the impact block.

10. The impact tool according to claim 1, characterized in that, At least two of each of the rolling ball, the first ball groove, and the second ball groove are provided.

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