CN220362529U

CN220362529U - Impact tool

Info

Publication number: CN220362529U
Application number: CN202321540172.9U
Authority: CN
Inventors: 李阳; 柯洪涛; 陈帅
Original assignee: Nanjing Chervon Industry Co Ltd
Current assignee: Nanjing Chervon Industry Co Ltd
Priority date: 2022-09-01
Filing date: 2023-06-16
Publication date: 2024-01-19
Anticipated expiration: 2033-06-16

Abstract

The application discloses an impact tool, including impact block and anvil, the impact block includes: the impact block body and the first end teeth are matched with the hammer anvil; the hammer anvil comprises a second end tooth matched with the impact block; wherein the first end tooth includes an impact surface and the second end tooth includes a secondary impact surface engaged with the impact surface; the first cambered surface with the contour line being an arc line is included from the impact surface; in the direction along the first center line, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth to the spindle axis is equal to or greater than 0.1 and equal to or less than 0.7. The impact tool of the present application has improved impact properties.

Description

Impact tool

Technical Field

The present application relates to power tools, and more particularly to impact tools.

Background

Impact tools in the market at present mainly comprise an impact screwdriver for driving screws and an impact wrench for screwing bolts. The impact wrench has large output torque force and needs the impact system to provide large impact force.

As the user's demands on the performance of impact tools are increasing, they are all placing higher demands on the performance of the impact system of the impact tool. Since the impact force of the impact tool mainly comes from the process of mutually matching engagement and disengagement of the impact block and the anvil, the structural rationality design of the impact block and the anvil has a great influence on the impact performance of the impact tool. The design of the configuration and dimensions of the impact block and anvil has a significant impact on the performance of the impact tool output.

This section provides background information related to the present application, which is not necessarily prior art.

Disclosure of Invention

It is an object of the present application to solve or at least mitigate some or all of the above problems. An object of the present application is to provide an impact tool having high impact properties.

In order to achieve the above object, the present application adopts the following technical scheme:

an impact tool, comprising: a motor including a drive shaft rotating about a first axis; the output shaft is used for outputting torque outwards; the output shaft rotates by taking the output axis as a rotating shaft; the impact mechanism is used for applying impact force to the output shaft; an impact mechanism, comprising: the device comprises a main shaft driven by a driving shaft, an impact block sleeved on the main shaft and an anvil matched with the impact block, wherein the anvil is connected with an output shaft; the main shaft rotates by taking the axis of the main shaft as the shaft; an impact block, comprising: the impact block body and the first end teeth are matched with the hammer anvil; the hammer anvil comprises a second end tooth matched with the impact block; the first end tooth including an impact surface and the second end tooth including a secondary impact surface engaged with the impact surface; the first cambered surface with the contour line being an arc line is included from the impact surface; in the direction along the first center line, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth to the spindle axis is 0.1 or more and 0.7 or less.

In some embodiments, a ratio of a length L1 of the impact surface to a distance L2 from an outermost end of the second end tooth to the spindle axis in a direction along the first centerline is greater than or equal to 0.2 and less than or equal to 0.5.

In some embodiments, the second end tooth is symmetrical about a first centerline, the first centerline being perpendicular to the spindle axis.

In some embodiments, the contour of the first arcuate surface is an arcuate line.

In some embodiments, the center of the contour of the first arcuate surface is located outside the first centerline.

In some embodiments, the anvil includes a central portion connected to the output shaft, the central portion connected to the second end tooth through a second arc surface, a step is formed between the first arc surface and the second arc surface, the step formed between the first arc surface and the second arc surface is smooth connected through a first transition surface, and the step formed from the impact surface to the second end tooth and including at least the first arc surface.

In some embodiments, the contour line of the second cambered surface is a circular arc line, and the center of the first cambered surface and the center of the second cambered surface are respectively located at two sides of the first central line.

In some embodiments, the anvil includes a central portion coupled to the output shaft, the central portion coupled to the second end teeth via a first transition surface that connects the first arcuate surface to the central portion.

In some embodiments, the outer contour of the first transition surface is an arc or a diagonal.

In some embodiments, when the impact mechanism outputs an impact force, the output of the output shaft has an impact kinetic energy of 10% or more of the impact kinetic energy of the impact block against the anvil.

An impact tool, comprising: a motor including a drive shaft rotating about a first axis; the output shaft is used for outputting torque outwards; the output shaft rotates by taking the output axis as a rotating shaft; the impact mechanism is used for applying impact force to the output shaft; an impact mechanism, comprising: the device comprises a main shaft driven by a driving shaft, an impact block sleeved on the main shaft and an anvil matched with the impact block, wherein the anvil is connected with the main shaft of an output shaft and rotates by taking the axis of the main shaft as a shaft; the impact block includes: the impact block body and the first end teeth are matched with the hammer anvil; the hammer anvil comprises a central part connected with the output shaft and second end teeth matched with the impact block; the anvil comprises a first center line, and the second end teeth are symmetrical about the first center line; the first end tooth including an impact surface and the second end tooth including a secondary impact surface engaged with the impact surface; the first cambered surface with the contour line being an arc line is included from the impact surface; in a direction perpendicular to the first center line, a ratio of a maximum width dimension W1 of a contour line from the impact surface to a maximum width dimension W2 at a junction of the second end tooth and the center portion is 0.4 or more and 1 or less.

The beneficial point of the application lies in: the impact tool provided by the application utilizes the impact surface of the arc curve and the optimized size proportion combined with the impact surface, so that the impact performance of the impact tool is improved, and the duration of the whole machine is further improved.

Drawings

FIG. 1 is a schematic view of an impact tool according to an embodiment of the present application;

FIG. 2 is a schematic illustration of a cross-sectional view of a construction of an impact tool provided in an embodiment of the present application;

FIG. 3 is a block circuit diagram of an impact tool provided in an embodiment of the present application;

FIG. 4 is a schematic diagram of an exploded view of a portion of the structure of FIG. 1;

FIG. 5 is a block diagram of an impact block and anvil of a first embodiment of the present application;

FIG. 6 is a schematic view of the anvil of FIG. 5;

FIG. 7 is a schematic block diagram of the impact block of FIG. 5;

FIG. 8 is a graph comparing energy absorption curves of an embodiment of the present application with those of the related art;

FIG. 9 is a graph comparing crash torque at an output torque according to an embodiment of the present application with a related art;

FIG. 10 is a plot of impact torque versus related art at another output torque for another embodiment of the present application;

FIG. 11 is a comparison of a endurance test of an embodiment of the present application and a related art;

fig. 12 is a block diagram of an anvil according to a second embodiment of the present application.

Detailed Description

Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings.

In this application, the terms "comprises," "comprising," "has," "having," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the present application, the term "and/or" is an association relationship describing an association object, meaning that three relationships may exist. For example, a and/or B may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" in this application generally indicates that the front-rear association object is an "and/or" relationship.

The terms "connected," "coupled," and "mounted" are used herein to describe either a direct connection, a coupling, or an installation, or an indirect connection, a coupling, or an installation. By way of example, two parts or components are connected together without intermediate members, and by indirect connection is meant that the two parts or components are respectively connected to at least one intermediate member, through which the two parts or components are connected. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings, and may include electrical connections or couplings.

In this application, one of ordinary skill in the art will understand that relative terms (e.g., "about," "approximately," "substantially," etc.) used in connection with quantities or conditions are intended to include the values and have the meanings indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a particular value, the tolerance associated with a particular value resulting from manufacture, assembly, use, and the like. Such terms should also be considered to disclose a range defined by the absolute values of the two endpoints. Relative terms may refer to the addition or subtraction of a percentage (e.g., 1%,5%,10% or more) of the indicated value. Numerical values, not employing relative terms, should also be construed as having specific values of tolerance. Further, "substantially" when referring to relative angular positional relationships (e.g., substantially parallel, substantially perpendicular) may refer to adding or subtracting a degree (e.g., 1 degree, 5 degrees, 10 degrees, or more) from the indicated angle.

In this application, one of ordinary skill in the art will understand that a function performed by a component may be performed by one component, multiple components, a part, or multiple parts. Also, the functions performed by the elements may be performed by one element, by an assembly, or by a combination of elements.

In the present application, the terms "upper", "lower", "left", "right", "front", "rear", and the like are described in terms of orientation and positional relationship shown in the drawings, and should not be construed as limiting the embodiments of the present application. In the context of this document, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on the other element or be indirectly on the other element through intervening elements. It should also be understood that the terms upper, lower, left, right, front, back, etc. are not only intended to represent positive orientations, but also to be construed as lateral orientations. For example, the lower side may include a right lower side, a left lower side, a right lower side, a front lower side, a rear lower side, and the like.

For clarity of description of the technical solutions of the present application, upper side, lower side, front side and rear side are defined in the drawings of the specification.

An impact tool according to an embodiment of the present application is shown in fig. 1 and 2. The impact tool is an impact screw driver 100. It will be appreciated that in other alternative embodiments the impact tool may be fitted with different working attachments by means of which the impact tool may be, for example, a drill hammer, an impact wrench or the like.

The impact screw 100 includes a power supply device. In the present embodiment, the power supply device is a dc power supply 30. Dc power supply 30 is used to provide power to impact screw driver 100. The dc power supply 30 is a battery pack that cooperates with a corresponding power circuit to power the impact screw driver 100. It should be understood by those skilled in the art that the power supply device is not limited to the use of a dc power supply, and may also be implemented to supply power to corresponding components in the machine by using a mains supply, an ac power supply, and a corresponding rectifying, filtering and voltage regulating circuit.

As shown in fig. 1 to 2, the impact screw 100 includes a housing 11, a motor 12, an output mechanism 15, a transmission mechanism 13, and an impact mechanism 14. Wherein the motor 12 comprises a drive shaft 121 rotating about a first axis 101. In the present embodiment, the motor 12 is specifically provided as a motor, and hereinafter, the motor 12 is replaced with a motor, and the drive shaft is replaced with the motor shaft 121, but this is not intended as a limitation of the present application.

The output mechanism 15 includes an output shaft 151 for connecting and driving the work attachment in rotation. The front end of the output shaft 151 is provided with a clamping assembly 152 for clamping corresponding working accessories, such as bits, drills, sleeves, etc., when performing different functions. In this embodiment, the output shaft 151 may drive the fastener by a driver head, for example, the fastener may be a screw. The motor 12 drives the output shaft 151 to rotate, which rotates the driver bit and fastener, thereby causing the fastener to be threaded into or out of the target workpiece.

The output shaft 151 outputs torque to the outside to operate the fastener, and the output shaft 151 rotates with the output axis, which is the second axis 102 in this embodiment. In this embodiment, the first axis 101 coincides with the second axis 102. In other alternative embodiments, the second axis 102 is disposed at an angle to the first axis 101. In other alternative embodiments, the first axis 101 and the second axis 102 are disposed parallel to each other but not coincident.

The housing 11 includes a motor case 111 for accommodating the motor 12 and an output case 112 accommodating at least part of the output assembly 13, the output case 112 being connected to a front end of the motor case 111. The housing 11 is also formed or connected with a grip 113 for user operation. The holding part 113 and the motor housing 112 form a T-shaped or L-shaped structure, which is convenient for a user to hold and operate. One end of the grip portion 113 is connected to the dc power supply 30. The motor 12, the transmission mechanism 13, the impact mechanism 14, and the output mechanism 15 are disposed in a motor housing 111 and an output housing 112.

The transmission 13 is arranged between the motor 12 and the impact mechanism 14 for effecting a transmission of power between the motor shaft 121 and the spindle 18. In the present embodiment, the transmission mechanism 13 employs planetary gear reduction. Since the principle of operation of planetary gear reduction and the reduction produced by such a transmission are well known to those skilled in the art, a detailed description is omitted here for the sake of brevity.

As shown in fig. 1-3, the motor 12 includes stator windings and a rotor. In some embodiments, the motor 12 is a three-phase brushless motor, including a rotor with permanent magnets and electronically commutated three-phase stator windings U, V, W. In some embodiments, a star connection is used between the three-phase stator windings U, V, W, and in other embodiments, an angular connection is used between the three-phase stator windings U, V, W. However, it is understood that other types of brushless motors are also within the scope of the present disclosure. Brushless motors may include fewer or more three-phase windings.

The impact screw 100 includes a control circuit. The control circuit includes a drive circuit 241 and a controller 24. The driving circuit 241 is electrically connected to the stator winding U, V, W of the motor 12 for transferring current from the dc power source 30 to the stator winding U, V, W to drive the motor 12 to rotate. In one embodiment, the driving circuit 241 includes a plurality of switching elements Q1, Q2, Q3, Q4, Q5, Q6. The gate terminal of each switching element is electrically connected to the controller 24 and is configured to receive a control signal from the controller 24. The drain or source of each switching element is connected to the stator winding U, V, W of the motor 12. The switching elements Q1-Q6 receive control signals from the controller 24 to change the respective conductive states and thereby vary the current applied by the dc power source 30 to the stator windings U, V, W of the motor 12. In one embodiment, the drive circuit 241 may be a three-phase bridge driver circuit including six controllable semiconductor power devices (e.g., field effect transistors (Field Effect Transistor, FETs), bipolar junction transistors (Bipolar Junction Transistor, BJTs), insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBTs), etc.). It will be appreciated that the switching element may be any other type of solid state switch, such as an Insulated Gate Bipolar Transistor (IGBT), a Bipolar Junction Transistor (BJT), etc.

In the present embodiment, the controller 24 is used to control the motor 12. The controller 24 is provided on a control circuit board including: printed circuit boards (Printed Circuit Board, PCB) and flexible circuit boards (Flexible Printed Circuit, FPC). The controller 24 employs a dedicated control chip, e.g., a single-chip microcomputer, micro-control module (Microcontroller Unit, MCU). The controller 24 controls the on or off state of the switching elements in the driving circuit 241 specifically by a control chip. In some embodiments, the controller 24 controls the ratio between the on-time and the off-time of the drive switch based on a pulse width modulation (Pulse Width Modulation, PWM) signal. It should be noted that the control chip may be integrated into the controller 24, or may be provided independently of the controller 24, and the structural relationship between the driving chip and the controller 24 is not limited in this embodiment.

The impact screw 100 further includes a main switch 21 and a switching section 23. The main switch 21 is provided on the grip portion 113 for operation by a user. The main switch 21 is used to control the energized state of the motor 12. The switching portion 23 is provided on the upper side of the main switch 21, and the switching portion 23 is configured to be operated to set the rotation direction of the motor 12 to the forward rotation direction in which the fastener is fastened or screwed in or the reverse rotation direction in which the fastener is unscrewed or unscrewed.

In the present embodiment, the main switch 21 is a trigger switch including an operation piece 211 and a slide rheostat 212 for operation. The main switch 21 can thus also regulate the rotational speed of the motor 12. The rotational speed of the motor 12 is adjusted according to the trigger stroke of the operation member 211. The trigger stroke of the operation member 211 is different, and the signal output from the slide rheostat 212 is different. The trigger stroke of the operation member 211 is in positive correlation with the duty ratio of the PWM signal of the motor 12, which is in positive correlation with the rotational speed of the motor 12. When the trigger stroke of the trigger switch is small, the duty ratio of the PWM signal is also small, and at this time, the rotation speed of the motor 12 is also small.

In some embodiments, the mapping relationship between the triggering stroke of the operation member 211 and the PWM signal is stored in the impact screw driver 100, and the mapping relationship may be linear or non-linear, which is not limited in the embodiments of the present application.

As shown in fig. 4 to 7, the impact mechanism 14 includes a main shaft 18, an impact block 19 fitted around the outer periphery of the main shaft 18, an anvil 17 provided at the front end of the impact block 19, and an elastic member 16. Wherein anvil 17 comprises anvil 171. The impact block 19 is driven by the main shaft 18, and the anvil 171 is engaged with and struck by the impact block 19, and the anvil 171 drives the output shaft 151 to rotate.

The impact block 19 includes an impact block main body 191 and a first end tooth 193 protruding forward from the front end surface of the impact block main body 191. In the present embodiment, the impact block body 191 is provided with third end teeth 194 radially symmetrically with respect to the first end teeth 193, that is, the first end teeth 193 and the third end teeth 194 are disposed 180 ° apart around the circumference of the main shaft 18. It will be appreciated that the impact block body 191 may also include more than 2 forwardly projecting end teeth, the plurality of end teeth being equally angularly spaced around the circumference of the main shaft 18. The anvil 171 is provided with second end teeth 172 protruding rearward on a rear end face thereof opposite to the impact block 19. In the present embodiment, the anvil 171 is provided with the fourth end teeth 173 radially symmetrical to the second end teeth 172, that is, the second end teeth 172 and the fourth end teeth 173 are disposed 180 ° apart around the circumference of the main shaft 18. It will be appreciated that the anvil 171 may also include more than 2 rearwardly projecting end teeth, with the plurality of end teeth being equally angularly spaced about the circumference of the main shaft 18.

The output shaft 151 extends out of the output housing 112. The output shaft 151 is connected to the anvil 171, it being understood that the anvil 171 and the output shaft 151 may be integrally formed or separately formed individual parts. The impact block 19 is supported on the main shaft 18 and is reciprocally slidable in the front-rear direction with respect to the main shaft 18. The resilient element 16 provides the impact block 19 with a force that brings it close to the anvil 17.

During operation of the impact screw 100, the impact block 19 is supported on the spindle 18 for rotation integrally with the spindle 18 and is reciprocally slidable relative to the spindle 18 in the axial direction of the spindle. In this embodiment, the spindle axis 103 coincides with the first axis 101. The impact block 19 includes a first position that moves forward to the most distal end and a second position that moves rearward to the most distal end. Wherein in the first position the impact block 19 is engaged with the anvil 17, i.e. the front end of the stroke of the impact block 19 is stopped by the anvil 17.

The impact block body 191 is also provided with a pair of first ball grooves (not shown) having openings extending forward and rearward in the front-rear direction on the front end surface thereof. The outer surface of the main shaft 18 is also formed with a pair of V-shaped second ball grooves 181. The first ball groove and the second ball groove 181 have groove bottoms that are both semicircular.

The impact mechanism 14 also includes a ball 141. The ball 141 spans the first ball groove and the second ball groove 181, thereby connecting the impact block 19 with the spindle 18. In this embodiment, the ball 141 is a steel ball.

The operation of the impact screw 100 is described below. When the spindle 18 rotates, the movement of the ball 141 in the second ball groove 181 allows the impact block 19 to move relatively to the spindle 18 in the front-rear direction. Specifically, when the impact screw driver 100 is unloaded or lightly loaded, the impact mechanism 14 does not impact, the impact mechanism 14 plays a role in transmission, the impact block 19 is in the first position, and rotation of the shaft of the motor 12 is transmitted to the main shaft 18 through the transmission assembly 13, so that the main shaft 18 rotates. Since the main shaft 18 rotates the impact block 19 by means of the ball 141 and the first end teeth 193 and the third end teeth 194 of the impact block 19 are engaged with the second end teeth 172 and the fourth end teeth 173 of the anvil 171, the anvil 17 rotates, and thus the output shaft 151 and the working head mounted on the output shaft 151 rotate. When the impact screw driver 100 is loaded, the rotation of the output shaft 151 is blocked, and the output shaft 151 cannot rotate along with the spindle 18 due to the different sizes of the loads, and the rotation may be completely stopped due to the reduction of the rotation speed. However, continued rotation of the spindle 18 causes the ball 141 at the rear end of the first ball groove to roll rearward along the second ball groove 181 of the spindle 18, thereby causing rearward displacement of the impact block 19 along the spindle axis 103, i.e., movement toward the second position of the impact block 19. While the impact block 19 presses the resilient element 16 until the impact block 19 is completely disengaged from the anvil 17, at which point the impact block 19 is in the second position. The elastic element 16 is rebounded to the impact block 19 along the spindle axis 103 to apply force, the rolling ball 141 rolls along the second ball groove 181, so that the rolling ball advances while rotating, at this time, the relative rotating speed between the impact block 19 and the anvil 17 is the rotating speed of the impact block 19, when the impact block 19 rotates to be in contact with the anvil 17, the end teeth of the impact block 19 impact the end teeth on the anvil 17, an impact force is applied to the anvil 17, under the action of the impact force, the output shaft 151 continuously rotates for a certain angle against the load, then the output shaft 151 stops rotating again, and the above processes are repeated, so that the intermittent application of the rotary impact force of the impact block 19 is realized, and the output force output is improved.

As shown in fig. 5-7, the first end tooth 193 includes an impact surface 193a and the second end tooth 172 includes a secondary impact surface 172a driven by the impact surface 193 a. From impact surface 172a into engagement with impact surface 193 a. The output shaft 151 is driven by the clockwise rotation of the spindle 18, and the impact surface 193a contacts the secondary impact surface 172a when the impact block 19 is rotated into contact with the anvil 17. In the present embodiment, the impact screw 100 can be switched to the main shaft 18 to rotate counterclockwise to drive the output shaft 151 by the switching portion 243. The impact block 19 includes a second centerline 19a and both the first end tooth 193 and the third end tooth 194 are symmetrical about the second centerline 19 a. The anvil 17 includes a first centerline 17a, and the second end tooth 172 and the fourth end tooth 173 are symmetrical about the first centerline 17 a. It will be appreciated that the end teeth on the impact block 19 and the end teeth on the anvil 17 each include two impact surfaces 193a and a slave impact surface 172a such that the impact surfaces 193a can strike and drive the slave impact surfaces 172a during both clockwise and counterclockwise rotation of the spindle 18.

Taking as an example the case when the main shaft 18 drives the output shaft 151 to rotate clockwise. The secondary impact surface 172a includes a first arcuate surface 1721 having an arcuate contour. The impact surface 193a includes a third arcuate surface 1931, the contour of the third arcuate surface 1931 being an arc that meshes with the first arcuate surface 1721. In the present embodiment, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth 172 to the spindle axis 103 in the direction along the first center line 17a is 0.1 or more and 0.7 or less. In the present embodiment, the length L1 from the impact surface is the effective collision length of the first end tooth 193 and the second end tooth 172 when they are in collision engagement, and the contact length when the first end tooth 193 is in collision engagement with the second end tooth 172 is also understood. In some embodiments, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth to the spindle axis 103 is greater than or equal to 0.2 and less than or equal to 0.6. In some embodiments, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth to the spindle axis 103 is greater than or equal to 0.2 and less than or equal to 0.5. In some embodiments, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth to the spindle axis 103 is 0.3, 0.4, 0.5, 0.6, 0.7. The impact life of the impact mechanism is affected by the length L1 of the impact surface, i.e. the effective length of the impact, and impact forces and impact stresses are affected. When the length L1 from the impact surface is too short, impact stress is concentrated. The short contact length from the impact surface to the impact surface tends to destabilize the impact and also destabilize the impact. When the length L1 from the impact surface is too long, the first end teeth of the impact block are also lengthened, so that the radial dimension of the impact block is increased, and the moment of inertia is affected.

The anvil 17 includes a central portion connected to the output shaft 151. In this embodiment, the center portion is an anvil 171. For convenience of description, the center portion is denoted by reference numeral 171 in the following description.

When the center portion 171 is connected to the second end teeth 172, the connection is smooth through an arc surface, an inclined surface, or the like. In the present embodiment, the contour line from the first cambered surface 1721 of the impact surface 172a is a circular arc line. The center of the contour line of the first arc surface 1721 is located outside the first center line 17 a. The center portion 171 and the second end tooth 172 are connected by a second arcuate surface 1722. Wherein, a step is formed between the first arc surface 1721 and the second arc surface 1722, and the step formed between the first arc surface 1721 and the second arc surface 1722 is connected smoothly through the first transition surface 1723. A secondary impact surface 172a is provided on the second end tooth 172, which, depending on the impact requirements in the embodiment, includes at least a first cambered surface from the impact surface 172a. And first transition surface 1723 and second arcuate surface 1722 may also be part of secondary impact surface 172a. In this embodiment, the secondary impact surface 172a includes a first arcuate surface 1721 and a first transition surface 1723.

The outline of the second arc surface 1722 is an arc line, and the center of the first arc surface 1721 and the center of the second arc surface 1722 are respectively located at two sides of the first central line 17 a.

The third arc surface 1931 is engaged with the first arc surface 1721 to drive the anvil 17 to rotate. The radius of the first transition surface 1723 is smaller than the radius of the first arcuate surface 1721.

For convenience of explanation, in this embodiment, it is set that: the radius of the first arcuate surface 1721 is R1; radius R2 of second arcuate surface 1722; the radius of the first transition surface 1723 is R3; the center of the first cambered surface 1721 is M1; the center of the second arc surface 1722 is M2; the center of the first transition surface 1723 is M3. The foregoing is provided for convenience of explanation of the technical solutions of the present application and is not intended to limit the essential content of the present application by reference numerals and designations.

In this embodiment, R2 is greater than R1, and the ratio of R1 to R2 is 0.91. In other alternative embodiments, the ratio of R1 to R2 may be 0.92, 0.93, 0.94, 0.95, 0.97. In this embodiment, R3 is less than R1, and the ratio of R3 to R1 ranges from 0.38 to 0.37. In the present embodiment, in the direction perpendicular to the first center line 17a, the distance from the center M1 of the first arc surface 1721 to the first center line 17a is D1, the distance from the center M2 of the second arc surface to the first center line 17a is D2, M1 and M2 are located on both sides of the first center line 17a, and D2 is greater than D1. In this embodiment, the ratio of D1 to R1 ranges from 0.4 to 0.5. Specifically, the ratio of D1 to R1 is 0.42, 0.44, 0.46, 0.48. In the present embodiment, M1 and M2 are substantially on the same straight line F in the direction perpendicular to the first center line 17 a.

The radius of the third curved surface 1931 of the impact surface 193a is equal to or less than the radius of the first curved surface 1721. The radius of the third curved surface 1931 is R4. In order to ensure the engagement degree between the third curved surface 1931 and the first curved surface 1721, R4 is less than or equal to R1. Wherein the first end tooth 193 further comprises: the first connection face 1932 closest to the spindle axis 103 is located outside of the first arcuate face 1721 when the first end tooth 193 drives the second end tooth 172. In this embodiment, upon engagement of the first end tooth 193 with the second end tooth 172, the first connection face 1932 at least partially engages the first transition face 1723. That is, upon impact, third arcuate surface 1931 collides with first arcuate surface 1721.

It will of course be appreciated that in other alternative embodiments, impact surface 193a further includes a fourth arcuate surface, and first connecting surface 1932 connects third arcuate surface 1931 with the fourth arcuate surface. The fourth arc surface meshes with the second arc surface 1722 to drive the anvil 17 to rotate. That is, upon impact, the third curved surface 1931 collides with the first curved surface 1721, and the fourth curved surface collides with the second curved surface 1722.

In other alternative embodiments, the central portion and the second end tooth are connected by a first transition surface, the first transition surface being a chamfer. The first transition surface connects the first cambered surface with the central part in a smooth manner.

In a direction perpendicular to the first center line 17a, a ratio of a maximum width dimension W1 from a contour line of the impact surface 172a to a maximum width dimension W2 at a junction of the second end tooth 172 and the center portion 171 is 0.4 or more and 1 or less. In the present embodiment, in the direction perpendicular to the first center line 17a, the maximum width dimension W1 of the contour line of the secondary impact surface 172a is two straight lines parallel to the first center line 17a, and the secondary impact surface 172a on both sides of the second end tooth 172 is located between the two straight lines, and the distance between the two straight lines is the maximum width dimension W1 of the contour line of the secondary impact surface 172a. The maximum width dimension W2 at the junction of the second end tooth 172 and the central portion 171 in the direction perpendicular to the first center line 17a is the root width of the second end tooth 173. I.e. two straight lines parallel to the first centre line 17a are provided, between which the connection of the two sides of the second end tooth 172 with the central portion 171 is between. It will be appreciated that the root of the second end tooth 173 is between two straight lines, and that more than two straight lines may be provided on either side of the central portion. The distance between these two straight lines is the maximum width dimension W2 where the second end tooth 172 joins the center portion 171. In some embodiments, the ratio of the maximum width dimension W1 from the contour of the impact surface 172a to the maximum width dimension W2 at the junction of the second end tooth 172 and the central portion 171 is 0.6 or more and 1 or less. In some embodiments, the ratio of the maximum width dimension W1 from the contour of the impact surface 172a to the maximum width dimension W2 at the junction of the second end tooth 172 and the central portion 171 is 0.5, 0.6, 0.7, 0.8, 0.9.

The maximum width dimension W2 of the junction of the second end tooth 172 and the central portion 171 is wider than the maximum width dimension W1 of the contour line from the impact surface 172a, that is, the junction of the second end tooth 172 and the central portion 171 is wider than the junction of the second end tooth and the first end tooth, and the heel portion of the second end tooth 172 has higher bending rigidity. The proportion of the material affects the curvature of the impact surface, and affects the rebound coefficient of the impact.

In the following, an impact wrench having a tightening torque of 1500n·m or more with respect to a workpiece by an impact tool will be taken as an example, and kinetic energy, moment of inertia, and the like during the operation of the impact wrench will be analyzed.

First, the bolt tightening process is divided into: the first stage, in the bolt fastening process; in the second stage, the bolts are fully tightened. Wherein the first stage comprises the very beginning of the impact.

Wherein, the moment of inertia of the impact block is set; is the equivalent rotational inertia of an output shaft, a sleeve, a bolt and a load. It is understood that the moment of inertia of the anvil.

In the first phase, the ratio of the values, i.e. the value, becomes gradually smaller. When the second stage is entered, the ratio of the ratio to the bolt, i.e. the value, approaches 0 when the bolt is fully tightened. When the impact is just started, the ratio to the value, i.e. the value is less than 10.

The ratio of the two to each other, namely/value, becomes gradually larger in the process of disassembling the bolts. The ratio to the impact, i.e., the value, approaches 0 when the impact is just started.

The impact wrench has a tightening torque of 1500n·m or more with respect to the work, and the moment of inertia of the impact block= 432.9kg·mm. Output shaft moment of inertia=12 kg·mm, sleeve moment of inertia=400 to 900 kg·mm. Thus, the ratio of the sum, i.e. the value, is less than 1.

In analyzing the kinetic energy conversion rate of the impact mass and anvil, an energy absorption curve is created. As shown in fig. 8, the abscissa thereof is the ratio of moment of inertia. The ordinate is the energy ratio. Wherein the 001 curve is the energy absorption curve of the impact mechanism in the related art; 002 curve is the energy absorption curve of the impact mechanism in this embodiment. Wherein, the related technology refers to: the end tooth structure of the impact block and anvil is a generally rectangular or rectangular-like shape of the existing impact mechanism structure. It can be seen that the energy absorption rate of the impact mechanism in this embodiment is superior to that of the impact mechanism in the related art. Particularly, in the bolt disassembling process, the efficiency is obviously improved compared with the related technology. The reason for this is that in improving the kinetic energy conversion rate by reducing the moment of inertia, when planar end teeth in the related art are applied, it is necessary to reduce the length of the end teeth that mesh with each other, and thus reduce the meshing area. Under the action of the required peak impact force, the local stress is increased. This improves the kinetic energy conversion rate but does not contribute to the product lifetime. In this embodiment, the intermeshing end teeth are cambered. Meanwhile, the second end tooth is further provided with a second cambered surface so that the second end tooth is in cambered connection with the anvil. The bending strength and the contact strength of the hammer anvil are improved, and the service life of the product is ensured. In this embodiment, when an impact occurs, the third cambered surface collides with the first cambered surface; and meanwhile, the peak impact force is reduced, so that the kinetic energy conversion rate is effectively improved. When the impact mechanism outputs impact force, the output impact kinetic energy of the output shaft accounts for more than or equal to 10% of the impact kinetic energy of the impact block to the anvil. Further, the output impact kinetic energy of the output shaft accounts for 12% or more of the impact kinetic energy of the impact block to the anvil, and further, the output impact kinetic energy of the output shaft accounts for 15% or more of the impact kinetic energy of the impact block to the anvil. Further, the output impact kinetic energy of the output shaft accounts for 17% or more of the impact kinetic energy of the impact block to the anvil. Further, the output impact kinetic energy of the output shaft accounts for 20% or more of the impact kinetic energy of the impact block to the anvil.

Using the formula i= (1+k) W ₀ Wherein I is a punchMoment, k is the rebound coefficient, W ₀ Is the angular velocity of the spindle.

Due to moment of inertia, springs, spindle angular velocity W ₀ The same, and then under the locked rotor, the meshing structure of the impact block and the anvil of the embodiment is used, the rebound coefficient k is large, and the energy transmitted to the output shaft under different k is combined, so that the cambered surface is used for meshing with the cambered surface, the energy obtained by the output shaft is large, the energy loss of collision is further reduced, the working efficiency and the working capacity are improved, and the heating is reduced.

In analyzing the impact moment of the impact block against the anvil against time accumulation, in this embodiment, impulse moment curves as shown in fig. 9 and 10 are established, the abscissa being the impact time and the ordinate being the impact moment of the impact block against the anvil. Wherein, in fig. 9, the fastening torque of the impact tool to the workpiece is 1500n·m, and the 003 curve is the impact mechanism in the related art; curve 004 is the impact mechanism in this embodiment. In fig. 10, the curve of the tightening torque 80n·m,003' of the impact tool to the workpiece is the impact mechanism in the related art; the 004' curve is the impact mechanism in this embodiment.

In this embodiment, the magnitude of the moment of impulse is equal to the product of the external moment acting on the object and the time of action (the direction is the same as the moment), and is also equal to the product of the impulse acting on the object and the moment arm (the direction is the same as the impulse). The impulse moment is represented by the envelope area of the envelope curve. Curves 003 and 004 are envelope curves. The 003 'curve and 004' curve are envelope curves. The moment of impulse can be used to describe the change in rotational state of an object. The moment of momentum imparted to the rotating object is equal to the change in moment of momentum of the rotating object over the period of time. As can be seen from fig. 9 and 10, the envelope area of the 004 'curve is larger than the envelope area of the 003' curve at the same moment of inertia, spring and spindle angular velocity, i.e. the moment of impulse in the present embodiment is larger than the moment of impulse in the related art. The reason for this is that, when an impact occurs, the third cambered surface collides with the first cambered surface, the peak impact force is reduced, but the high torque output time is long.

In one embodiment, when the fastening torque of the impact tool to the workpiece is 1500n·m, the impact moment of the impact block is 125N ·m·s or more. In some embodiments, the moment of impulse is 138N-m-s, and in the related art, the moment of impulse is 122N-m-s.

As an example, when the fastening torque of the impact tool to the workpiece is 80n·m, the impact moment of the impact block is 13N ·m·s or more. In some embodiments, the moment of impulse is 15N-m-s, and in the related art, the moment of impulse is 12N-m-s.

When the fastening torque of the impact tool to the workpiece is 60-120 N.m, the impact torque is increased by 10% compared with that in the related art.

As shown in fig. 11, the impact screw with the tightening torque of the impact tool to the workpiece of 80n·m was measured using the same battery pack (the battery pack is used as 2P in this example, and the battery capacity is 5 Ah), and a endurance test was performed. By using the impact mechanism of the related art and the impact mechanism of the present embodiment for screw tightening, it consumes electricity by the number of screws that are driven after completion. 1/4 ". Times.3 pine, 3/8". Times.3 pine, 8 ". Times.200 pine, 3/8". Times.3 technical wood, and 8 ". Times.200 technical wood were used as experimental pieces, respectively. The ordinate of the graph indicates the number of screws driven in after the battery pack is used until its power consumption is completed. Wherein, the broken outline column is the data of the impact mechanism using the related art, and the solid outline column is the data of the impact mechanism of the embodiment of the present application. Compared with the related art, the cruising duration of the embodiment of the application is 10% more. It can be known that the impact performance and the overall performance of the novel high-performance impact-resistant rubber are improved.

As shown in fig. 12, a second embodiment of the present application. Wherein the secondary impact surface of the second end tooth 272 of the anvil 27 includes a first contact surface 2721 having a straight contour.

The anvil 27 includes a central portion connected to the output shaft. Wherein in the present embodiment, the central portion is an anvil 271. For convenience of description, the center portion is denoted by reference numeral 271 in the following description.

When the center portion 271 and the second end teeth 272 are connected, they are smoothly connected by an arc surface. The center portion 271 and the second end teeth 272 are connected by a second arcuate surface 2722. Wherein, a step is formed between the first contact surface 2721 and the second arc surface 1722, and the step formed between the first contact surface 2721 and the second arc surface 2722 is connected smoothly through the first transition surface 2723. Wherein, the outer contour of the first transition surface 2723 is also an arc surface. And simultaneously, the first transition surface 2723 and the second cambered surface 2722 respectively have inner and outer circular arcs. That is, depending on the structure and size of the first contact surface 2721 and the central portion 271, the first transition surface 2723 may be an inner arc and the second arc surface 2722 may be an outer arc in different impact structures. In some embodiments, the first transition surface 2723 is an outer arc and the second arc surface 2722 is an inner arc. In this embodiment, the first transition surface 2723 is an inner arc, and an angle formed between tangent lines at two ends of the first transition surface 2723 is less than or equal to 145 °. Optionally, an angle formed between tangents at both ends of the first transition surface 2723 is 140 ° or less.

The foregoing has outlined and described the basic principles, main features and advantages of the present application. It will be appreciated by persons skilled in the art that the above embodiments are not intended to limit the present application in any way, and that all technical solutions obtained by means of equivalent substitutions or equivalent transformations fall within the scope of the present application.

Claims

1. An impact tool, comprising:

a motor including a drive shaft rotating about a first axis;

the output shaft is used for outputting torque outwards; the output shaft rotates by taking an output axis as a rotating shaft;

an impact mechanism for applying an impact force to the output shaft;

it is characterized in that the method comprises the steps of,

the impact mechanism includes: a main shaft driven by the driving shaft, an impact block sleeved on the main shaft and an anvil matched with the impact block;

the main shaft rotates by taking the main shaft axis as a shaft;

the impact block includes: an impact block body and first end teeth engaged with the anvil;

the anvil comprises a second end tooth matched with the impact block;

the first end tooth including an impact surface and the second end tooth including a secondary impact surface engaged with the impact surface;

the secondary impact surface comprises a first cambered surface with an arc contour line; in the direction along the first center line, the ratio of the length L1 of the impact surface to the distance L2 from the outermost end of the second end tooth to the spindle axis is 0.1 or more and 0.7 or less.

2. The impact tool of claim 1, wherein a ratio of the length L1 of the impact surface to a distance L2 from an outermost end of the second end tooth to the spindle axis in a direction along the first center line is 0.2 or more and 0.5 or less.

3. The impact tool of claim 1, wherein the second end tooth is symmetrical about the first centerline, the first centerline being perpendicular to the spindle axis.

4. A stroker tool according to claim 3, wherein the contour of the first cambered surface is a circular arc.

5. The impact tool of claim 4, wherein a center of a contour of the first arcuate surface is located outside of the first centerline.

6. The impact tool of claim 1, wherein the anvil includes a central portion connected to the output shaft, the central portion being connected to the second end tooth by a second arcuate surface, a step being formed between the first arcuate surface and the second arcuate surface, the step formed between the first arcuate surface and the second arcuate surface being smooth connected by a first transition surface, the secondary impact surface being formed on the second end tooth and including at least the first arcuate surface.

7. The impact tool of claim 6, wherein the contour line of the second arc surface is an arc line, and the center of the first arc surface and the center of the second arc surface are located at two sides of the first center line respectively.

8. The impact tool of claim 1, wherein the anvil includes a central portion connected to the output shaft, the central portion and the second end tooth being connected by a first transition surface that connects the first arcuate surface to the central portion in a fairing.

9. The impact tool of claim 8, wherein the outer contour of the first transition surface is an arc or a diagonal line.

10. The impact tool according to claim 1, wherein when the impact mechanism outputs an impact force, the output of the output shaft has an impact kinetic energy of 10% or more of the impact kinetic energy of the impact block to the anvil.

11. An impact tool, comprising:

a motor including a drive shaft rotating about a first axis;

an impact mechanism for applying an impact force to the output shaft;

it is characterized in that the method comprises the steps of,

the main shaft rotates by taking the main shaft axis as a shaft;

the hammer anvil comprises a central part connected with the output shaft and second end teeth matched with the impact block; the anvil includes a first centerline about which the second end teeth are symmetrical;

the first end tooth including an impact surface and the second end tooth including a secondary impact surface engaged with the impact surface; the secondary impact surface comprises a first cambered surface with an arc contour line; in the direction perpendicular to the first center line, the ratio of the maximum width dimension W1 of the contour line from the impact surface to the maximum width dimension W2 at the junction of the second end tooth and the center portion is 0.4 or more and 1 or less.