CN215431664U - Impact drill - Google Patents

Abstract

The utility model discloses a percussion drill, which comprises a casing and a driving assembly arranged in the casing, wherein a bearing is sleeved on an output shaft of the driving assembly, the percussion drill further comprises a static ratchet wheel, a dynamic ratchet wheel and a switching assembly, the static ratchet wheel is fixedly arranged in the casing, the output shaft movably penetrates through the static ratchet wheel, the dynamic ratchet wheel is fixedly sleeved on the output shaft and is abutted against the bearing, ratchets are arranged on the opposite end surfaces of the static ratchet wheel and the dynamic ratchet wheel, and the switching assembly controls the ratchets on the static ratchet wheel and the ratchets on the dynamic ratchet wheel to be mutually clutched so as to switch the working mode of the percussion drill. Compared with the prior art, the assembly for switching the working modes has the advantages of simpler structure, easiness in manufacturing and convenience in assembling and replacing.

Description

Impact drill

Technical Field

The utility model belongs to the field of electric tools, and particularly relates to a percussion drill.

Background

The percussion drill is a commonly used electric tool, a drill chuck is arranged on an output shaft of a driving assembly, the driving assembly drives the drill chuck to rotate to work, and different drilling tools such as a drill bit, a screw tap or a reamer can be installed on the drill chuck according to working requirements. The percussion drill with high performance on the current market has two different working modes: the electric drill comprises a drilling mode and an impact mode, wherein the impact drill in the drilling mode has functions similar to those of a common electric drill, and can be used for drilling materials such as wood boards and the like which can be drilled with small force; in the impact mode, a hard material such as concrete or stone can be drilled by using the rotation of the drilling tool and the high impact frequency. In order to realize the switching of two working modes in the prior art, a ball type switching structure is generally adopted and comprises a movable disc, a fixed disc and steel balls, wherein the movable disc is in threaded connection with an output shaft and is provided with a plurality of steel balls; after the pin is disengaged, the fixed disc can rotate along with the movable disc without impact, and the fixed disc is switched to a drilling mode, so that the fixed disc has the function of a common electric drill. The switching structural design of this kind of ball formula is comparatively complicated and occupation space is big, complex operation during the assembly, is unfavorable for later maintenance and overhaul.

In addition, part percussion drill still has the torque adjustment function, and it is connected with drive assembly through gear mechanism with the output shaft rear end, and gear mechanism can be used to slow down output shaft rotational speed and then increase output torsion, and the regulation of moment of torsion is realized through the mode of mechanical regulation among the prior art, for example, adjust the torsion cover and to single torsion spring compress tightly the degree and then adjust output torque. The mode of adjusting the torque can realize the adjustment purpose only by applying a large acting force on one hand, and on the other hand, the adopted parts are very many, the occupied space is large, the design structure is complex and the assembly is tedious.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a percussion drill, which can effectively solve the problems of complex switching structure, large occupied space and complex assembly in the prior art for switching the working mode of the percussion drill.

In order to solve the technical problems, the utility model adopts the following technical scheme: the utility model provides an impact drill, includes the casing and installs the drive assembly in the casing, the cover is equipped with the bearing on drive assembly's the output shaft, still includes quiet ratchet, moves ratchet and switching component, quiet ratchet fixed mounting is in the casing, quiet ratchet is worn to establish in the output shaft activity, move the fixed cover of ratchet and establish on the output shaft and with the bearing butt, quiet ratchet all is equipped with the ratchet with moving on the relative terminal surface of ratchet, switching component control ratchet on the quiet ratchet with move the ratchet on the ratchet and separate and reunion each other in order to switch the mode of impact drill.

Preferably, the switching subassembly includes bearing housing and elastic component, the fixed cover of bearing housing is established on the outer lane of bearing, the elastic component is connected between quiet ratchet and bearing housing, be equipped with first spacing arch on the bearing housing, be equipped with the spacing arch of second on the quiet ratchet, when staggering each other of first spacing bellied terminal surface and the spacing bellied terminal surface of second, the percussion drill is in the impact mode, overcomes the elasticity rotation bearing housing of elastic component makes the mutual butt of first spacing bellied terminal surface and the spacing bellied terminal surface of second, and the percussion drill is in drilling mode. Utilize first spacing protruding and the mutual butt of second spacing protruding to make the unable relative quiet ratchet of ratchet along axial displacement, make the percussion drill in drilling mode like this, first spacing protruding and second spacing protruding lose the limiting displacement who moves the ratchet after staggering each other, move the ratchet and can relative quiet ratchet axial displacement and contact, the percussion drill switches into the impact mode.

Preferably, the elastic piece is a spring, the elastic piece is sleeved on the movable ratchet wheel, one end of the elastic piece is connected with the static ratchet wheel, the other end of the elastic piece is connected with the bearing sleeve, and the movable ratchet wheel overcomes the elasticity of the elastic piece to move towards the static ratchet wheel and is in contact with the static ratchet wheel in the impact mode.

Preferably, the switching component further comprises a rotary sleeve, a first bump is arranged on the outer surface of the bearing sleeve, a second bump used for shifting the first bump is arranged in the rotary sleeve, and the rotary sleeve overcomes the elasticity of the elastic piece to drive the bearing sleeve to rotate. The rotary sleeve is arranged, so that an operator can conveniently switch the rotary sleeve.

Preferably, the casing includes tooth case shell, tooth case shell is equipped with the sleeve, the bearing housing rotates to be connected in the sleeve, rotatory cover rotates the cover and establishes outside the sleeve, be equipped with the spacing hole that supplies first lug to stretch out on the sleeve, the pore wall in spacing hole and first lug cooperate and are used for restricting the turned angle of bearing housing.

Preferably, an elastic sheet is arranged between the rotary sleeve and the sleeve and used for limiting the rotary sleeve after the rotary sleeve rotates to the position.

Preferably, the drive assembly comprises a variable speed motor, and the percussion drill further comprises an adjustment assembly for adjusting the output speed of the variable speed motor in the drilling mode.

Preferably, the adjusting assembly comprises a PCB and an induction element, the PCB is mounted on the housing, the PCB is provided with a plurality of hall sensors, each hall sensor is preset with a different voltage value, the hall sensor is connected to the variable speed motor, the hall sensor sends a corresponding voltage value to the variable speed motor to control the output rotation speed of the variable speed motor when being turned on, and the induction element moves relative to the PCB to align the induction element and turn on the corresponding hall sensor. Through setting up PCB board and inductive element and replacing torsion spring among the prior art, also change the mode of mechanical adjustment into electronic control, can save occupation space when adjusting the precision higher, satisfy the miniaturized trend of instrument to reduce the assembly degree of difficulty.

Preferably, the PCB board is cyclic annular, and is a plurality of hall sensor sets up along PCB board circumference, adjusting part still includes the torque cup, sensing element fixed mounting is in the torque cup, and it is rotatory the torque cup makes sensing element rotate to aim at with different hall sensor.

Preferably, the induction element is magnetic steel.

Compared with the prior art, the utility model has the following beneficial effects: ratchets are respectively arranged on the movable ratchet wheel and the static ratchet wheel, and the ratchets on the movable ratchet wheel and the ratchets on the static ratchet wheel are mutually separated in the drilling mode; in the impact mode, an operator tightly supports a drilling tool of the impact drill on a drilled object, so that the output shaft receives a reaction force along the axial direction, the ratchets on the movable ratchet wheel and the ratchets on the static ratchet wheel are interacted, the movable ratchet wheel rotates along with the output shaft due to the fact that the static ratchet wheel is fixed, the ratchets on the movable ratchet wheel and the ratchets on the static ratchet wheel are meshed with each other or the end faces of the ratchets on the static ratchet wheel tightly support each other, and the output shaft drives the drilling tool to rotate and simultaneously perform impact reciprocating motion to achieve the impact function. The ratchets are directly arranged on the movable ratchet wheel and the static ratchet wheel, the steel balls do not need to be assembled like the prior art, the occupied space is reduced, and meanwhile, the assembly, the maintenance, the disassembly and the assembly are simpler and more convenient.

Drawings

FIG. 1 is a schematic view of a percussion drill according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a static ratchet wheel, a dynamic ratchet wheel, a bearing and an output shaft in the first embodiment;

FIG. 3 is a schematic structural diagram of a stationary ratchet, a movable ratchet, a bearing, a switching assembly and an output shaft in the first embodiment;

FIG. 4 is a schematic structural diagram of a middle gearbox shell, a static ratchet wheel, a dynamic ratchet wheel, a bearing, a switching assembly and an output shaft of the embodiment;

FIG. 5 is an exploded view of the first embodiment of the utility model, including the tooth case, the spring, the stationary ratchet, the movable ratchet, the bearing, the switching assembly, the output shaft, and the rotating sleeve;

FIG. 6 is a schematic diagram illustrating the first bump and the second bump abutting each other in the first embodiment;

FIG. 7 is a cross-sectional view of the rotating sleeve, spring and tooth case shell of the embodiment;

FIG. 8 is an exploded view of the gearbox housing and adjustment assembly of the second embodiment.

Wherein: 1. the mechanical hand comprises a shell, 10 parts of a gearbox shell, 11 parts of a sleeve, 110 parts of limiting holes, 111 parts of elastic sheets, 1110 parts of a boss, 2 parts of a driving component, 20 parts of an output shaft, 200 parts of a bearing, 21 parts of a drill chuck, 3 parts of a static ratchet wheel, 31 parts of a static ratchet, 32 parts of a second limiting boss, 4 parts of a dynamic ratchet wheel, 41 parts of a dynamic ratchet wheel, 5 parts of a bearing sleeve, 51 parts of a first limiting boss, 52 parts of a first bump, 6 parts of an elastic piece, 7 parts of a rotating sleeve, 71 parts of a second bump, 72 parts of a clamping groove, 73 parts of a clamping hole, 8 parts of a PCB board, 80 parts of a Hall sensor and 9 parts of a sensing element.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the utility model and are not to be construed as limiting the utility model.

In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the terms "mounted," "connected," "fixed," and the like are to be construed broadly and may, for example, be fixedly connected or detachably connected or integrated; may be mechanically coupled, may be electrically coupled or may be in communication with each other; may be directly connected or indirectly connected through an intermediate, unless otherwise specifically limited. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The first embodiment is as follows: as shown in fig. 1 to 5, the percussion drill provided by this embodiment includes a casing 1, a driving assembly 2 is installed in the casing 1, a drill chuck 21 is disposed at a front end of an output shaft 20 of the driving assembly 2, the drill chuck 21 may be used to fixedly install different drilling tools, such as a drill bit, a screw tap, a reamer, etc., the driving assembly 2 drives the output shaft 20 to rotate, and the output shaft 20 drives the drilling tools to rotate through the drill chuck 21, thereby implementing a function of screwing screws or drilling holes. The output shaft 20 of the driving component 2 is sleeved with a bearing 200, and is further sleeved with a static ratchet wheel 3 and a dynamic ratchet wheel 4, wherein the static ratchet wheel 3 is fixedly installed in the casing 1, the output shaft 20 movably penetrates through the static ratchet wheel 3, the dynamic ratchet wheel 4 is fixedly sleeved on the output shaft 20 and is abutted against the bearing 200, ratchets are arranged on the opposite end surfaces of the static ratchet wheel 3 and the dynamic ratchet wheel 4, for convenience of description, ratchets arranged on the static ratchet wheel 3 are called static ratchets 31, and ratchets arranged on the dynamic ratchet wheel 4 are called dynamic ratchets 41. The percussion drill further comprises a switching assembly, the switching assembly controls the static ratchet 31 and the movable ratchet 4 to be mutually clutched so as to switch the working mode of the percussion drill, specifically, the static ratchet 31 and the movable ratchet 41 are mutually separated in the drilling mode, and the static ratchet 31 and the movable ratchet 41 mutually interact to enable the output shaft 20 to reciprocate in the impacting mode. In this embodiment, the driving component 2 is a motor, in addition, a gearbox housing 10 is further arranged in the casing 1 in this embodiment, a sleeve 11 is arranged on the gearbox housing 10, wherein the static ratchet wheel 3, the movable ratchet wheel 4 and the bearing 200 are all located in the sleeve 11, and the static ratchet wheel 3 is fixedly assembled and connected with the gearbox housing 10.

In the impact drill provided by the embodiment, the movable ratchet 4 and the static ratchet 3 are respectively provided with ratchets, and the static ratchet 31 and the movable ratchet 41 are separated from each other in a drilling mode; in the impact mode, an operator tightly supports a drilling tool of an impact drill on a drilled object, so that the output shaft 20 receives a reaction force along the axial direction, the static ratchet 31 and the movable ratchet 41 are interacted, the movable ratchet 4 rotates along with the output shaft 20 due to the fact that the static ratchet 3 is fixed, the movable ratchet 41 and the static ratchet 31 are meshed with each other or the end faces of the movable ratchet 31 are tightly supported, in the process, the movable ratchet 41 axially reciprocates relative to the static ratchet 31, and the output shaft 20 drives the drilling tool to rotate and simultaneously perform impact reciprocating motion to achieve the impact function. The ratchets are directly arranged on the movable ratchet wheel 4 and the static ratchet wheel 3, the steel balls do not need to be assembled like the prior art, the occupied space is small, and the assembling, maintaining, dismounting and mounting operations are simpler and more convenient. In addition, the rotating speed of the output shaft 20 and the number of the ratchets are positively correlated with the impact frequency of the impact drill, and under the condition of inconvenient rotating speed, the more the ratchets are, the higher the impact frequency is, and the difficulty and the cost of production and manufacturing can hardly be improved by increasing the number of the ratchets, so that the design and the manufacture are convenient, and the application range is wider.

The switching component in this embodiment includes bearing housing 5 and elastic component 6, wherein elastic component 6 in this embodiment adopts the spring, bearing housing 5 fixed cover is established on the outer lane of bearing 200, elastic component 6 is connected between quiet ratchet 3 and bearing housing 5, specifically, elastic component 6 cover is established on moving ratchet 4, the one end and the quiet ratchet 3 of elastic component 6 are connected, the other end and the bearing housing 5 of elastic component 6 are connected, when bearing housing 5 moved along the axial or along circumferential direction like this, elastic component 6 all had the reset action to bearing housing 5. In this embodiment, the bearing sleeve 5 is provided with the first limiting protrusion 51, the static ratchet wheel 3 is provided with the second limiting protrusion 32, when the end surface of the first limiting protrusion 51 and the end surface of the second limiting protrusion 32 are staggered, the percussion drill is in a percussion mode, when the percussion drill works in the mode, a drilled object exerts a reaction force on a working head, and then the movable ratchet wheel 4 is pushed to overcome the elasticity of the elastic part 6 to move towards the static ratchet wheel 3 and contact with the static ratchet wheel 3, so that a percussion function is realized. After the percussion drill stops working, the static ratchet wheel 3, the bearing sleeve 5 and the like return to the original position under the elastic action of the elastic piece 6, at the moment, the bearing sleeve 5 is rotated by overcoming the elastic force of the elastic piece 6, so that the end surface of the first limiting bulge 51 is abutted against the end surface of the second limiting bulge 32, and the percussion drill is in a drilling mode. The movable ratchet wheel 4 cannot move relative to the static ratchet wheel 3 along the axial direction by utilizing the mutual abutting of the first limiting protrusion 51 and the second limiting protrusion 32, so that the impact drill is in a drilling mode, the first limiting protrusion 51 and the second limiting protrusion 32 lose the limiting effect on the movable ratchet wheel 4 after being staggered, the movable ratchet wheel 4 can move and contact relative to the static ratchet wheel 3 in the axial direction, and the impact drill is switched to an impact mode.

In the present embodiment, the switching assembly further includes a rotating sleeve 7, and as shown in fig. 4, fig. 5 and fig. 6, a first protrusion 52 is disposed on an outer surface of the bearing sleeve 5, a second protrusion 71 for poking the first protrusion 52 is disposed in the rotating sleeve 7, and the rotating sleeve 7 is screwed to overcome the elastic force of the elastic member 6 to drive the bearing sleeve 5 to rotate. The rotary sleeve 7 is arranged to facilitate switching operation of an operator, the rotary sleeve is sleeved outside the sleeve 11, a limiting hole 110 for the first bump 52 to extend out is correspondingly formed in the sleeve 11, and the hole wall of the limiting hole 110 is matched with the first bump 52 to limit the rotation angle of the bearing sleeve 5. Correspondingly, marks corresponding to different working modes are arranged on the outer surface of the rotary sleeve 7, so that an operator can conveniently observe the marks. In addition, as shown in fig. 7, in order to keep the screwed sleeve relatively fixed after being screwed in place, in this embodiment, an elastic sheet 111 is further disposed between the rotary sleeve 7 and the sleeve 11, the elastic sheet 111 is used for limiting the rotary sleeve 7 after the rotary sleeve 7 is rotated in place, specifically, a plurality of slots 72 are disposed on an inner ring of the rotary sleeve 7, a protrusion 1110 adapted to the slots 72 is disposed on the elastic sheet 111, the protrusion 1110 is clamped into the slot 72 by an elastic force of the elastic sheet 111 to limit the rotary sleeve 7, when the rotary sleeve 7 needs to be screwed, the elastic sheet 111 is forcibly screwed, the elastic sheet 111 can extend in a circumferential direction by overcoming the elastic force of the elastic sheet 111, and thus the protrusion 1110 is separated from the slot 72, and rotation is achieved.

Different working modes need to be switched by applying the percussion drill provided by the embodiment, when the drilling mode needs to be switched to the impact mode, only the rotary sleeve 7 needs to be screwed, the rotary sleeve 7 is rotated to correspond to the mark of the impact mode, the second bump 71 drives the bearing sleeve 5 to rotate through the first bump 52 in the process, the end surfaces of the first limiting bulge 51 and the second limiting bulge 32 are staggered after the bearing sleeve 5 rotates in place, and at the moment, the elastic force of the elastic piece 6 can be overcome to keep the position fixed because the rotary sleeve 7 is limited by the elastic piece 111. When the impact drill is used, an operator pushes and presses the impact drill to tightly abut against the surface of a drilled object, under the reaction force of the drilled object to the working head, the output shaft 20 drives the movable ratchet wheel 4 to move and contact relative to the static ratchet wheel 3, so that the movable ratchet wheel 41 contacts with the static ratchet wheel 31 and rotates, the output shaft 20 rotates and reciprocates, and the impact action of the working head is realized. When the impact mode needs to be switched to the drilling mode, the rotating sleeve 7 is reversely screwed, the bearing sleeve 5 rotates under the action of the elastic force of the elastic piece 6 and returns to the original position, and the end surface of the first limiting protrusion 51 is abutted to the end surface of the second limiting protrusion 32, so that an operator cannot drive the movable ratchet wheel 4 to axially move relative to the static ratchet wheel 3 by the bearing 200 when using the tool, cannot generate an impact function and can only rotate.

Example two: the present embodiment also provides a percussion drill, as shown in fig. 8, the present embodiment is different from the above-mentioned embodiments in that the motor in the present embodiment is a variable speed motor, and the percussion drill further includes an adjusting assembly for adjusting the speed of the output shaft 20 of the variable speed motor in the drilling mode, so as to adjust the output torque of the output shaft 20. Based on above-mentioned difference technical characteristics, this percussion drill that this embodiment provided still has the regulation moment of torsion function under drilling mode, can adapt to more work scenes, enlarge working range, promote work efficiency simultaneously.

Specifically, the adjusting component in this embodiment includes PCB board 8 and sensing element 9, PCB board 8 is installed on casing 1, be equipped with a plurality of hall sensor 80 on the PCB board 8, different voltage values have been preset to every hall sensor 80, hall sensor 80 is connected with variable speed motor, send corresponding voltage value to variable speed motor when hall sensor 80 opens in order to control variable speed motor's output speed, sensing element 9 moves relative to PCB board 8 and makes sensing element 9 aim at and open corresponding hall sensor 80, sensing element 9 is the magnet steel in this embodiment. The working principle is as follows: the variable speed motor is internally provided with a protection plate, the protection plate is provided with corresponding overcurrent protection according to different voltage values, therefore, when the induction element 9 is aligned to the corresponding Hall sensor 80 and opened, the Hall sensor 80 transmits the preset voltage value to the protection plate, and the protection plate starts the corresponding overcurrent protection according to the voltage value, so that the rotating speed of the variable speed motor can be controlled within a threshold value, different voltage values correspond to different overcurrent protection values, and correspondingly, different rotating speed threshold values are also corresponding, so that the torque can be adjusted. Through setting up PCB board 8 and inductive element 9 and replacing torsion spring among the prior art, also change the mode of mechanical adjustment into electronic control, can save occupation space when adjusting the precision higher, satisfy the miniaturized trend of instrument to reduce the assembly degree of difficulty.

Further, PCB board 8 in this embodiment is cyclic annular, directly with 8 suit of PCB board outside sleeve 11, a plurality of Hall sensors 80 set up along 8 circumference of PCB board, adjusting part still includes the torque cup, and inductive element 9 fixed mounting is in the torque cup, and rotatory torque cup makes inductive element 9 rotate to aim at with different Hall sensors 80, and then can arouse Hall sensor 80 to open and send corresponding voltage value to variable speed motor. For convenience of assembly and saving of parts, the torsion cup in this embodiment may be the rotating sleeve 7 in the first embodiment, which is also described in the first embodiment: the sleeve 11 is provided with a limiting hole 110, and the hole wall of the limiting hole 110 is matched with the first bump 52 to limit the bearing sleeve 5. Therefore, when the working mode needs to be switched, only the torque cup (i.e. the rotating sleeve 7 in the above embodiment) needs to be rotated to rotate the second protrusion 71 to drive the first protrusion 52 to rotate, and when the torque needs to be adjusted in the drilling mode, the second protrusion 71 is rotated to avoid the first protrusion 52. Correspondingly, gear marks can be arranged on the outer ring surface of the torque cup, and the number and the positions of the gear marks correspond to the Hall sensors 80 one by one. Referring to fig. 6, in the present embodiment, a locking hole 73 is formed in the torque cup, the sensing element 9 is fixedly locked in the locking hole 73, and the position of the locking hole 73 is close to the position of the second protrusion 71, so that the structure is compact, and the torque can be adjusted immediately after the gear is shifted. It should be noted that the adjustment of the output torque of the impact drill in the drilling mode provided by the embodiment refers to a function of adjusting the torque when screwing is performed, and no operation of adjusting the torque is required in the drilling mode.

The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto, and any changes or modifications within the scope of the present invention by those skilled in the art are covered by the present invention.

Claims (10)

1. The utility model provides a percussion drill, includes casing (1) and installs drive assembly (2) in casing (1), the cover is equipped with bearing (200), its characterized in that on output shaft (20) of drive assembly (2): still include quiet ratchet (3), move ratchet (4) and switching subassembly, quiet ratchet (3) fixed mounting is in casing (1), quiet ratchet (3) are worn to establish in the activity of output shaft (20), move ratchet (4) fixed cover and establish on output shaft (20) and with bearing (200) butt, quiet ratchet (3) and move the ratchet all are equipped with the ratchet on the relative terminal surface of ratchet (4), switching subassembly control ratchet on quiet ratchet (3) and move the ratchet on ratchet (4) and separate and reunion each other in order to switch the mode of percussion drill.

2. A percussion drill according to claim 1, wherein: the switching component comprises a bearing sleeve (5) and an elastic piece (6), the bearing sleeve (5) is fixedly sleeved on an outer ring of a bearing (200), the elastic piece (6) is connected between a static ratchet wheel (3) and the bearing sleeve (5), a first limiting bulge (51) is arranged on the bearing sleeve (5), a second limiting bulge (32) is arranged on the static ratchet wheel (3), when the end surface of the first limiting bulge (51) and the end surface of the second limiting bulge (32) are staggered mutually, the impact drill is in an impact mode, the impact drill is overcome, the elastic force of the elastic piece (6) rotates the bearing sleeve (5) to enable the end surface of the first limiting bulge (51) and the end surface of the second limiting bulge (32) to abut against each other, and the impact drill is in a drilling mode.

3. A percussion drill according to claim 2, wherein: elastic component (6) are the spring, elastic component (6) cover is established on moving ratchet (4), the one end and the quiet ratchet (3) of elastic component (6) are connected, the other end and the bearing housing (5) of elastic component (6) are connected, move the elasticity that ratchet (4) overcome elastic component (6) during impact mode and move to quiet ratchet (3) and contact with quiet ratchet (3).

4. A percussion drill according to claim 2, wherein: the switching assembly further comprises a rotary sleeve (7), a first bump (52) is arranged on the outer surface of the bearing sleeve (5), a second bump (71) used for stirring the first bump (52) is arranged in the rotary sleeve (7), and the rotary sleeve (7) overcomes the elasticity of the elastic piece (6) to drive the bearing sleeve (5) to rotate.

5. A percussion drill according to claim 4, wherein: casing (1) includes tooth case shell (10), tooth case shell (10) are equipped with sleeve (11), bearing housing (5) rotate to be connected in sleeve (11), rotatory cover (7) rotate the cover and establish outside sleeve (11), be equipped with spacing hole (110) that supply first lug (52) to stretch out on sleeve (11), the pore wall and first lug (52) of spacing hole (110) cooperate and are used for restricting the turned angle of bearing housing (5).

6. A percussion drill according to claim 5, wherein: an elastic sheet (111) is arranged between the rotary sleeve (7) and the sleeve (11), and the elastic sheet (111) is used for limiting the rotary sleeve (7) after the rotary sleeve (7) rotates in place.

7. A percussion drill according to any one of claims 1 to 6, wherein: the driving assembly (2) comprises a variable speed motor, the percussion drill further comprises an adjusting assembly, and the adjusting assembly is used for adjusting the output rotating speed of the variable speed motor in the drilling mode.

8. A percussion drill according to claim 7, wherein: the adjusting assembly comprises a PCB (printed circuit board) and an induction element (9), the PCB (8) is installed on the casing (1), a plurality of Hall sensors (80) are arranged on the PCB (8), different voltage values are preset on the Hall sensors (80), the Hall sensors (80) are connected with the variable speed motor, corresponding voltage values are sent to the variable speed motor to control the output rotating speed of the variable speed motor when the Hall sensors (80) are opened, and the induction element (9) moves relative to the PCB (8) to enable the induction element (9) to be aligned and open the corresponding Hall sensors (80).

9. A percussion drill according to claim 8, wherein: PCB board (8) are cyclic annular, and are a plurality of hall sensor (80) set up along PCB board (8) circumference, adjusting part still includes the torque cup, sensing element (9) fixed mounting is in the torque cup, and is rotatory the torque cup makes sensing element (9) rotate to aim at with different hall sensor (80).

10. A percussion drill according to claim 8, wherein: the induction element (9) is magnetic steel.

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