CN214135874U - Electric hammer - Google Patents

Abstract

The utility model relates to an electric hammer, include: a motor; an impact mechanism; a first transmission mechanism; a second transmission mechanism; and (4) rotating the sleeve. The electric hammer comprises a reduction box, the reduction box comprises a box body and a gear train accommodated in the box body, the box body comprises a front shell at least partially accommodating the air cylinder, a middle shell covering the gear train, and a lower shell matched and connected with the middle shell. The technical effects are as follows: the cylinder internal diameter that the electric hammer chose for use is 25mm, and this cylinder internal diameter can guarantee relatively big hammering efficiency, can guarantee relatively little occupation space again, simultaneously, chooses for use smaller size motor, can make electric hammer light in weight for staff's the operation degree of difficulty descends, labour saving and time saving more, and the comfort is better with experience.

Description

Electric hammer

Technical Field

The utility model relates to an electric tool technical field especially relates to an electric hammer.

Background

The electric hammer is an electric rotary hammer drill with a pneumatic hammering mechanism, a drill bit can rotate and generate rapid reciprocating impact along the direction of an electric drill rod, the electric hammer drill is usually applied to the field of engineering construction such as building, decoration and installation, can drill holes in operation objects such as concrete, floors, brick walls and stones, and has the advantages of high working efficiency and flexible use.

The traditional electric hammer is mainly made of metal materials, so that the whole machine has better supporting strength and mechanical strength. Different cylinder bore diameters can produce different hammering efficiencies.

In the process of implementing the conventional technique, the inventors found that: traditional electric hammer complete machine's weight is great, has increased staff's the operation degree of difficulty, changes to light and thin material and reduces the cylinder internal diameter and can improve this problem, but leads to hammering efficiency can not up to standard easily again.

SUMMERY OF THE UTILITY MODEL

Based on this, it is necessary to be great to the weight of traditional electric hammer complete machine, has increased staff's the operation degree of difficulty, changes to light and thin material and reduces the cylinder internal diameter and can improve this problem, but leads to the problem that hammering efficiency can not up to standard easily, provides an electric hammer.

An electric hammer comprising: the motor mechanism comprises a motor and a motor shaft extending out of the motor; the impact mechanism comprises a cylinder, a piston accommodated in the cylinder, a hammer accommodated in the cylinder and matched with the piston, and a striking rod accommodated in the cylinder and matched with the hammer; the first transmission mechanism is matched with the motor shaft and provides impact force for the piston to reciprocate along the impact direction; the second transmission mechanism is matched with the motor shaft and provides driving force for the cylinder to rotate around the impact direction; the rotating sleeve is at least partially accommodated in the cylinder and partially extends out of the cylinder; wherein the inner diameter of the cylinder is 25mm, the weight of the hammer is between 62g and 75g, and the weight of the plunger is between 80g and 90 g.

The technical scheme at least has the following technical effects: the electric hammer that this technical scheme provided, the cylinder internal diameter of selecting for use is 25mm, and this cylinder internal diameter can guarantee relatively big hammering efficiency, can guarantee relatively little occupation space again, simultaneously, can also reduce the weight of cylinder relatively, and then reduce the weight of complete machine. Under the condition of selected cylinder internal diameter, the weight of ram sets up to 62g to 75g, and the weight of lance sets up to 80g to 90g, under the prerequisite of guaranteeing hammering efficiency, the ram of this scope, the weight of lance can also reduce the required time of drilling, improves work efficiency, has also reduced the weight of complete machine simultaneously relatively for staff's the operation degree of difficulty descends, labour saving and time saving more, and the comfort is better with experience sense.

In one embodiment, the weight of the ram is 66g and the weight of the ram is 85 g.

In one embodiment, the motor has a stack length of between 30mm and 35mm, wherein the stack length of the motor is defined as the overlap length of the rotor and the stator.

In one embodiment, the stack length of the motor is 30 mm.

In one embodiment, the stack length of the motor is 35 mm.

In one embodiment, the cylinder and the rotating sleeve are overlapped in the direction parallel to the impact direction, and the overlapped part is connected with the impact direction through a connecting piece.

In one embodiment, the electric hammer further comprises a reduction gearbox, the reduction gearbox comprises a box body and a gear train contained in the box body, and the box body is made of metal materials.

In one embodiment, the box body is made of magnesium alloy or aluminum alloy.

In one embodiment, the electric hammer further comprises a reduction gearbox, the reduction gearbox comprises a box body and a gear train contained in the box body, and the box body is made of plastic materials.

In one embodiment, the housing of the reduction gearbox includes a front housing at least partially housing the cylinder, a middle housing covering the gear train, and a lower housing coupled to the middle housing.

An electric hammer comprising: a motor having a motor shaft, the motor having a stack length of between 30mm and 35 mm; the impact mechanism comprises a cylinder, a piston which is accommodated in the cylinder and reciprocates along a working axis, a hammer matched with the piston and a ram matched with the hammer, wherein the inner diameter of the cylinder is 25mm, and the working axis is perpendicular to the axis of the motor shaft; the first transmission mechanism is matched with the motor shaft and provides impact force for the piston to move along the working axis; the second transmission mechanism is matched with the motor shaft and provides driving force for the cylinder to rotate around the working axis; the rotating sleeve is connected with the second transmission mechanism and is used for accommodating at least part of the working head and driving the working head to rotate; the electric hammer comprises a reduction box, the reduction box comprises a box body and a gear train contained in the box body, the box body comprises a front shell at least partially containing the air cylinder, a middle shell covering the gear train, and a lower shell matched and connected with the middle shell.

The technical scheme at least has the following technical effects: the electric hammer that this technical scheme provided, the cylinder internal diameter of selecting for use is 25mm, and this cylinder internal diameter can guarantee relatively big hammering efficiency, can guarantee relatively little occupation space again, simultaneously, can also reduce the weight of cylinder relatively, and then reduce the weight of complete machine. Under the condition of selecting the cylinder internal diameter, the axis of working axis perpendicular to motor shaft forms vertical structure, for traditional obtuse angle mode, has reduced the volume of the structure of acceping between cylinder and the motor, has alleviateed the weight of acceping the structure, and then has alleviateed the weight of complete machine for staff's the operation degree of difficulty descends, labour saving and time saving more, and the comfort is better with experience.

In one embodiment, the average wall thickness of the tank is between 2mm and 4 mm.

In one embodiment, the box body is a metal box body, and the electric hammer further comprises a plastic shell for accommodating the metal box body.

In one embodiment, the metal box is made of magnesium alloy or aluminum alloy.

In one embodiment, the plastic housing has an average wall thickness of 2.5 mm.

In one embodiment, the ratio of the number of times the ram impacts the ram per unit time to the number of revolutions of the sleeve is between 3.5 and 4.

In one embodiment, the weight of the ram is between 62g and 105g and the weight of the ram is between 75g and 90 g.

In one embodiment, the weight of the ram is between 62g and 75g and the weight of the ram is between 80g and 85 g.

In one embodiment, the total weight of the electric hammer is not more than 4.2 kg.

In one embodiment, the front case is detachably coupled to the middle case, and the middle case is detachably coupled to the lower case.

Drawings

Fig. 1 is a schematic structural view of an electric hammer according to an embodiment of the present invention;

FIG. 2 is a partial schematic view of the structure of FIG. 1 adjacent a chuck;

fig. 3 is a schematic structural view of an electric hammer according to another embodiment of the present invention;

fig. 4 is a partial schematic view of the structure of fig. 3 adjacent to a chuck.

Wherein:

100. electric hammer 110, motor mechanism 120, and impact mechanism

122. Cylinder 124, piston 126, ram

128. Striker 130, first transmission 132, and gear

134. Eccentric connecting rod 140, second transmission mechanism 150 and rotating sleeve

160. Chuck 170, connector 180, front housing

182. Middle shell 184, lower shell 190, shock pad

200. Electric hammer 210, motor 220, and impact mechanism

222. Cylinder 224, piston 226, ram

228. Striker 230, first transmission 232, gear

234. Eccentric connecting rod 240, second transmission mechanism 250 and rotating sleeve

260. Chuck 270, sliding structure 280, front shell

282. Middle shell 284, lower shell 290, plastic shell

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that the term "weight" as used herein refers to a physical quantity in kg or g, equivalent to a mass, and is not gravity.

The shell, the reduction gearbox and the like of the traditional electric hammer are usually mainly made of metal materials, and the whole electric hammer can have better supporting strength and mechanical strength by the arrangement. The impact mechanism of the electric hammer generally includes a cylinder, a piston accommodated in the cylinder, a hammer accommodated in the cylinder and engaged with the piston, and a striker accommodated in the cylinder and engaged with the hammer. It is generally considered that the hammering efficiency of the electric hammer is mainly determined by the selected cylinder bore, and under the same conditions, the larger the cylinder bore is, the larger the hammering efficiency is. Meanwhile, the smaller the inner diameter of the cylinder, the lighter the weight of the whole machine, and the larger the inner diameter of the cylinder, the heavier the weight of the whole machine. How to balance the relationship between the hammering efficiency and the weight of the whole hammer is a problem needing to be studied deeply, and the two problems influence the working efficiency and the operation convenience of the electric hammer.

Generally, those skilled in the art reduce the weight of the electric hammer by reducing the cylinder bore, but the hammering efficiency is affected. Increasing the power of the motor for this purpose results in an increase in the stack length of the motor, and thus in an increase in the size and weight of the motor, with the result that the weight of the electric hammer may increase again.

In view of this problem, the inventors thought that the size reduction of the cylinder bore should be limited, which is necessary, otherwise the work efficiency is extremely difficult to meet the requirements; attempts may then be made to improve the impact mechanism to ensure efficiency. When the problem is researched, the unexpected discovery that the weight of a proper ram and a proper ram rod are selected and matched with the proper inner diameter of the cylinder can achieve the aim of balancing the hammering efficiency and the weight of the whole machine.

To this end, referring to fig. 1 to 2, an embodiment of the present invention provides an electric hammer 100, including: the motor mechanism 110 comprises a motor and a motor shaft extending out of the motor, wherein the motor can drive the motor shaft to rotate; an impact mechanism 120 including a cylinder 122, a piston 124 housed in the cylinder 122, a hammer 126 housed in the cylinder 122 and engaged with the piston 124, and a striker 128 housed in the cylinder 122 and engaged with the hammer 126; a first transmission mechanism 130, which is engaged with the motor shaft, and provides an impact force for the piston 124 to reciprocate in the impact direction; a second transmission mechanism 140, which is engaged with the motor shaft and provides a driving force for the cylinder 122 to rotate in the impact direction; a rotating sleeve 150, which is partially accommodated in the cylinder 122 and partially extends out of the cylinder 122; a chuck 160 installed at a portion of the rotary sleeve 150 extending out of the cylinder 122; wherein the cylinder 122 has an inner diameter of 25mm, the weight of the ram 126 is between 62g and 75g, and the weight of the ram 128 is between 80g and 90 g. It should be noted that the numerical values presented herein are all error tolerant.

The first transmission mechanism 130 is an eccentric structure, and includes a gear 132 directly or indirectly engaged with the motor shaft and an eccentric connecting rod 134 driven by the gear 132, and the eccentric connecting rod 134 is connected with the piston 124. That is, the motor shaft drives the gear 132 to rotate, so as to drive the eccentric connecting rod 134 arranged eccentrically to drive the piston 124 to reciprocate in the cylinder 122 to compress air, so that the air pressure in the cylinder 122 is changed periodically, and the ram 126 and the ram 128 are driven to reciprocate to impact the working head. The impact direction is the direction of the arrangement of the piston 124, the ram 126, the ram 128, and the collet 160.

The second transmission mechanism 140 includes a bevel gear driven by a motor shaft, the cylinder 122 is also provided with another bevel gear engaged with the bevel gear, the cylinder 122 rotates by the engagement of the bevel gear and the cylinder 122, the cylinder 122 drives the rotating sleeve 150, and the rotating sleeve 150 drives the working head mounted on the chuck 160 to rotate synchronously.

The collet 160 is positioned on and removably secured to the portion of the rotating sleeve 150 extending out of the cylinder 122, and the working head is lockingly mounted to the collet 160.

Through the research of the inventor, when the inner diameter of the cylinder 122 is 25mm, the hammering efficiency of the electric hammer 100 is relatively high, and various working conditions, such as concrete, floor slabs, brick walls, stone and other operation objects, can be drilled. It will be appreciated that the cylinder 122 has an internal diameter of 25mm, allowing for some tolerance, and may be a value less than or greater than 25 mm. The inventor has conducted a series of experimental verifications based on the inner diameter of the cylinder 122 being 25mm, and has sought higher working efficiency by changing the weight of the ram 126 and the ram 128, where the working efficiency of the electric hammer 100 refers to the time taken to drill holes of the same diameter and depth under the same working conditions.

Specifically, the weight of the hammer 126 is set to m1 in g, the weight of the striker 128 is set to m2 in g, the time taken to drill the hole is set to t in s, the hole diameter is set to d in mm, and the depth of the hole is set to l in mm. Table 1 shows the time taken to drill holes having the same hole diameter and the same depth in the same operation target, assuming that the weight of the ram 128 is 85g and the weight of the hammer 126 is changed, under the same other conditions.

TABLE 1

As can be seen from table 1, in the art of electric hammer 100, as the weight of the hammer 126 increases, the working efficiency of the hammer 100 also increases accordingly, but considering: when the weight of the ram 126 is lower than 62g, the elastic potential energy of the air spring formed between the inner wall of the cylinder 122 and the ram 126 pushes the ram 126 to reciprocate, which makes it difficult to significantly reduce the working efficiency of the electric hammer 100; when the weight of the hammer 126 is higher than 75g, the elastic potential energy of the air spring formed between the inner wall of the cylinder 122 and the hammer 126 and the elastic potential energy of the hammer 128 at the time of rebounding are easily disturbed, causing the hammer 126 and the hammer 128 to continuously collide seriously, resulting in energy loss, lowering the working efficiency of the electric hammer 100, and affecting the comfort in operation. Accordingly, the weight of the ram 126 selected for use in the embodiments provided herein is 62g to 75 g. Specifically, 62g, 64g, 66g, 68g, 68.5g, 70g, 72g, 74g, 75g may be mentioned.

Further, table 2 shows a relationship between the weight of the hammer 126 and the weight of the striker 128.

TABLE 2

m1	60	62	66	75	92	102
							m2	85	85	85	85	81	80
m1/m2	0.70588	0.72941	0.77647	0.88235	1.1358	1.275

Table 2 is a set of comparisons of the weight ratio of the ram 126 and ram 128 provided in this embodiment with other prototype electric hammers 100 available in the market for some weight ratios. It can be seen that in the present embodiment, when the weight of the striker 128 is set to 85g, the weight of the hammer 126 is in the range of 62g to 75g, and the weight ratio of the hammer 126 to the striker 128 is in the range of 0.72941 to 0.88235.

Table 3 is a broken line view of the weight ratio of the hammer 126 to the striker 128 in table 2.

TABLE 3

With reference to tables 1 to 3, in the range where the weight of the hammer 126 is 62g to 75g, the working efficiency of the electric hammer 100 is relatively high, and at the same time, the weight of the hammer 126 is relatively reduced, improving the convenience of operation. When the weight of the striker 128 is changed on the assumption that the weight of the hammer 126 is unchanged, the experimental contents are the same as those described above, and will not be described herein again, and it is verified through a lot of experiments that when the weight of the striker 128 is 80g to 90g, such as 80g, 82g,84g,85g, 86g,88g,90g, the working efficiency of the electric hammer 100 is relatively high, and at the same time, the weight of the striker 128 is relatively reduced, and the convenience of operation is improved. The weight of the whole machine is lighter, the occupied space is relatively reduced, and the miniaturization and the lightness of the whole machine of the electric hammer 100 are realized.

The technical scheme at least has the following technical effects: the electric hammer 100 that this technical scheme provided, the cylinder 122 internal diameter of choosing for use is 25mm, and this cylinder 122 internal diameter can guarantee relatively big hammering efficiency, can guarantee relatively little occupation space again, simultaneously, can also reduce the weight of cylinder 122 relatively. Under the condition of selecting the cylinder 122 internal diameter, the weight of ram 126 sets up to 62g to 75g, and the weight of lance 128 sets up to 80g to 90g, under the prerequisite of guaranteeing hammering efficiency, the required time of drilling can also be reduced to the weight of ram 126, lance 128 of this scope, improves work efficiency, has also reduced the weight of complete machine relatively simultaneously for staff's the operation degree of difficulty descends, labour saving and time saving more, and the comfort is better with experience.

In some embodiments, the weight of the ram 126 is 66g and the weight of the ram 128 is 85 g. In the case of the experimental verification, when the weight of the selected ram 126 is 66g and the weight of the selected ram 128 is 85g, a relatively high working efficiency can be ensured, and a relatively low overall weight can be achieved.

In some embodiments, the motor has a stack length of between 30mm and 35mm, wherein the stack length of the motor is defined as the overlap length of the rotor and the stator. The length of folding of traditional motor is generally 40mm and above, and occupation space is great relatively, and in this embodiment, through reducing the length of folding of motor, the occupation space of reduction motor, and then reduces the weight of motor to reduce the weight of complete machine. Compared with the traditional motor stack length, the weight of the motor can be reduced by 50g to 100g relatively in the embodiment.

Generally, the reduction of the stacking length of the motor leads to the reduction of the output power of the motor, the increase of the temperature of the motor and the reduction of the working efficiency. However, the inventors have found through research that: when the stacking length of the motor is within the range of 30mm to 35mm, the output power and the temperature condition of the motor can meet the use requirement of the electric hammer 100 when the inner diameter of the air cylinder 122 is 25mm, so that the working efficiency of the electric hammer 100 can be ensured, and the weight of the electric hammer 100 can be reduced.

Specifically, the motor stack length is set to h in mm, the time taken to drill the hole is t in s, the hole diameter is d in mm, and the hole depth is set to l in mm. Table 4 shows the time taken to drill the same hole diameter and the same depth in the same operation target with different motor stack lengths under the same conditions.

TABLE 4

As can be seen from table 4, the motor length of the stack in the range of 30mm to 35mm is relatively short, and the time taken for drilling is relatively short compared to the motor length of 40mm, so that the motor length of the stack can be selected in a range of a small length on the premise of ensuring the working efficiency, thereby reducing the weight of the motor and thus the weight of the electric hammer 100. Specifically, it may be 30mm, 31mm, 32mm, 32.5mm, 33mm, 34mm, 35 mm.

If the motor length of the stack is further reduced, although the weight of the motor is reduced, the service life of the motor is affected due to the effect of the slot filling rate of the motor when the working load is larger, and therefore, the motor type with the lower length of the stack is not considered any more.

Further, the stack length of the motor is 30mm or 35 mm. In order to reduce the time for selecting and producing the motor, the length of the motor stack is set to be 30mm or 35mm, the type of the motor meeting the requirements can be directly selected within the range of the current standard, and special selection or production is not needed.

Referring to fig. 2, in some embodiments, there is an overlap of the cylinder 122 and the swivel sleeve 150 parallel to the impact direction, and the overlapped portion is connected perpendicular to the impact direction by a connector 170. The sleeve 150 is partially nested within the cylinder 122 so there is overlap parallel to the direction of impact, here the axial direction of the sleeve 150 or cylinder 122. The cylinder 122 is connected with the rotating sleeve 150 through a connecting piece 170, so that the cylinder 122 can drive the rotating sleeve 150 to synchronously rotate, and the working head mounted on the chuck 160 is driven to rotate. Specifically, the connection member 170 may employ a cylindrical pin, i.e., a cylindrical pin that penetrates the connection cylinder 122 and the rotary sleeve 150 in a direction perpendicular to the impact direction (radial direction). So set up, this junction is located the outside of complete machine, when dismantling swivel sleeve 150, only need dismantle chuck 160 part, demolish the cylindric lock again, just can dismantle swivel sleeve 150, and the detachability is strong, easy maintenance. As shown in fig. 4, the conventional sliding structure 270 includes a sliding groove and a ball body capable of sliding in the sliding groove, the excessive energy is unloaded by the cooperation of the sliding groove and the ball body in the axial direction, and the partial structure has a certain weight and also occupies a certain space. In this embodiment, the sliding structure is eliminated, and the length of the sliding distance is eliminated, so that the length of the rotating sleeve 150 can be reduced by about 10mm, and the weight of the rotating sleeve 150 is relatively lighter than 50 g.

In some embodiments, the electric hammer 100 further includes a reduction box, and the reduction box includes a box body and a gear train accommodated in the box body, and the box body is made of metal. The housing can partially or completely house the impact mechanism 120. The case serves as a carrier and a receptacle for the gear train and impact mechanism 120. The box of metal material can guarantee certain structural strength.

Specifically, the housing of the reduction gearbox includes a front housing 180 that at least partially houses the cylinder, a middle housing 182 that covers the gear train, and a lower housing 184 that mates with the middle housing 182. The front housing 180, the middle housing 182, and the lower housing 184 may be partially integrally formed or may be joined together. The gear train refers to at least part of the first transmission mechanism 130 and the second transmission mechanism 140. The front housing 180, the middle housing 182, and the lower housing 184 are sealingly engaged, and removably attached, to facilitate servicing of the internal components. For example, the front housing 180 and the middle housing 182 are sealed by a gasket or sealant, and locked by a pin, a snap, or a screw. As is the case between the middle housing 182 and the lower housing 184.

Furthermore, the box body is made of magnesium alloy or aluminum alloy. The magnesium alloy and the aluminum alloy have low density, and are lighter than iron, copper and other materials under the condition of the same volume, so that the weight of the reduction gearbox can be reduced, and the weight of the whole machine is reduced. The reduction gearbox can be made by casting.

As a specific embodiment, the front case 180, the middle case 182, and the lower case 184 constituting the metal case are made of magnesium alloy or aluminum alloy, and the weight of the entire case is reduced by reducing the weight of the front case 180, the middle case 182, and the lower case 184, so that the weight of 100g or more can be relatively reduced. At this time, the thicknesses of the different housings may be determined according to the difference of the bearing force and the supporting force.

As another specific solution, the front housing 180, the middle housing 182 and the lower housing 184 may be made of magnesium alloy or aluminum alloy. In this case, the distribution of the shells made of different materials can be determined according to the difference between the bearing force and the supporting force.

As still another specific example, the front case 180, the middle case 182, and the lower case 184 may be made of a magnesium alloy or an aluminum alloy. At this time, the distribution of the shells made of different materials is determined according to the difference of the bearing force and the supporting force.

In other embodiments, the electric hammer 100 further includes a reduction box, and the reduction box includes a box body and a gear train accommodated in the box body, and the box body is made of plastic. The plastic material is also low in density, and is lighter in weight compared with materials such as iron and copper under the condition of the same volume, so that the weight of the reduction gearbox can be reduced, and the weight of the whole machine is reduced. The reduction gearbox can be manufactured in an injection molding mode.

Specifically, the housing of the reduction gearbox includes a front housing 180 that at least partially houses the cylinder, a middle housing 182 that covers the gear train, and a lower housing 184 that mates with the middle housing 182. Similarly, the front housing 180, the middle housing 182 and the lower housing 184 can alternatively, alternatively or additionally be made of plastic. And will not be described in detail herein.

In addition, the front case 180, the middle case 182, and the lower case 184 constituting the box body may be made of plastic material, alternatively, metal material, alternatively. For example, when the middle case 182 is made of a plastic material and the front case 180 and the lower case 184 are made of a magnesium alloy material, the weight of 150g or more can be relatively reduced.

In other embodiments, referring to FIG. 2, the cylinder 122 is provided with a plurality of damping pads 190 around the circumference of the striker 128. In order to reduce the impact force caused by the impact of the ram 126 on the ram 128 and reduce the vibration of the cylinder 122, a plurality of shock absorbing pads 190 are disposed on the cylinder 122 in the circumferential direction close to the ram 128, specifically, on both sides of the supporting bearing outside the cylinder 122, and at the end of the cylinder 122 engaged with the rotating sleeve 150, so as to improve the stability of the cylinder 122 in motion.

Referring to fig. 3 and 4, an embodiment of the present invention further provides an electric hammer 200, including: a motor 210 having a motor shaft, the motor being capable of driving the motor shaft to rotate; an impact mechanism 220 including a cylinder 222, a piston 224 housed in the cylinder 222 and reciprocating along a working axis, a hammer 226 fitted to the piston 224, and a ram 228 fitted to the hammer 226, wherein the cylinder 222 has an inner diameter of 25mm, and the working axis is perpendicular to an axis of a motor shaft; a first transmission mechanism 230, cooperating with the motor shaft, providing an impact force for the movement of the piston 224 along the working axis; a second transmission mechanism 240, cooperating with the motor shaft, for providing a driving force for the cylinder 222 to rotate around the working axis; the rotating sleeve 250 is connected with the second transmission mechanism 240 and used for accommodating at least part of the working head and driving the working head to rotate; the total weight of the electric hammer 200 is not more than 4.2 kg.

It should be noted that the "overall weight" mentioned herein refers to the weight of the bare hammer 200 without the power cord, the auxiliary handle, and the working head. The cylinder 222 has an inner diameter of 25mm and may have a certain fluctuation margin within a tolerance range, and the inner diameter of the cylinder 222 may be 25 ± 1 mm. The "perpendicular" referred to herein allows for some angular error.

For the working axis, when the cylinder 222 is not eccentrically rotated, the working axis is the central axis of the cylinder 222; when the cylinder 222 rotates eccentrically, the working axis is parallel to the central axis of the cylinder 222. The working axis defines a direction of impact in which the ram 226 strikes the ram 228, and both the ram 226 and the ram 228 are housed within the cylinder 222.

The first transmission mechanism 230 is an eccentric structure, and includes a gear 232 directly or indirectly engaged with the motor shaft and an eccentric link 234 driven by the gear 232, and the eccentric link 234 is connected with the piston 224. That is, the motor shaft drives the gear 232 to rotate, so as to drive the eccentric connecting rod 234 arranged eccentrically to drive the piston 224 to reciprocate in the cylinder 222 to compress air, so that the air pressure in the cylinder 222 changes periodically, and the ram 226 and the ram 228 are driven to reciprocate to impact the working head. The impact direction is the arrangement direction of the piston 224, the hammer 226, the plunger 228, and the collet 260.

The second transmission mechanism 240 includes a bevel gear driven by a motor shaft, the cylinder 222 is also provided with another bevel gear engaged with the bevel gear, the cylinder 222 rotates by the engagement of the bevel gear and the cylinder 222, the cylinder 222 drives the rotating sleeve 250, and the rotating sleeve 250 drives the working head mounted on the chuck 260 to rotate synchronously.

The collet 260 is positioned on and removably secured to the portion of the sleeve 250 extending from the cylinder 222 and the working head is lockingly mounted to the collet 260.

Through the research of the inventor, when the inner diameter of the cylinder 222 is 25mm, the hammering efficiency of the electric hammer 200 is relatively high, and various working conditions, such as concrete, floor slabs, brick walls, stone and other operation objects, can be drilled.

The traditional working axis is generally obtuse with the axis of the motor shaft, the accommodating structure for accommodating the cylinder and the motor is large in size, and operation is laborious. Under the condition of selecting the inner diameter of the cylinder 222, the working axis is set to be perpendicular to the axis of the motor shaft to form a vertical structure, the size of the accommodating structure between the cylinder and the motor is reduced, the weight of the accommodating structure is reduced, and further the weight of the whole machine is reduced, so that the obtained weight of the whole machine is not more than 4.2kg, the operation difficulty of workers is reduced, time and labor are saved, and the comfortable feeling and the experience feeling are better.

The whole weight of the traditional electric hammer is about 5kg, so that the whole hammer is heavy when in use. In this embodiment, on the basis that the inner diameter of the selected cylinder 222 and the working axis are perpendicular to the axis of the motor shaft, the overall weight of the electric hammer 200 is relatively reduced, and can be less than or equal to 4.2kg, so that the portability of the electric hammer 200 is improved. The weight of the whole machine can be 4.2kg, 4.0kg, 3.8kg, 3.6kg, 3.4kg, 3.2kg, 3.0kg, 2.8kg, etc. according to the material and volume of the accommodating structure, and the specific values are not limited to the above examples.

The technical scheme at least has the following technical effects: the electric hammer 200 that this technical scheme provided, the cylinder 222 internal diameter of choosing for use is 25mm, and this cylinder 222 internal diameter can guarantee relatively big hammering efficiency, can guarantee relatively little occupation space again, simultaneously, can also reduce the weight of cylinder 222 relatively, and then reduce the weight of complete machine. Under the condition of selecting the internal diameter of the cylinder 222, the working axis is perpendicular to the axis of the motor shaft to form a vertical structure, so that the volume of the accommodating structure between the cylinder 222 and the motor 210 is reduced, the weight of the accommodating structure is reduced, the weight of the whole machine is not more than 4.2kg, the operation difficulty of workers is reduced, time and labor are saved, and the comfort and experience are better.

In some embodiments, the hammer 200 comprises a reduction gearbox comprising a housing and a gear train housed within the housing, the housing having an average wall thickness of between 2mm and 4 mm. The housing may also partially or fully house the impact mechanism 220. The case serves as a carrier and a receptacle for the gear train and impact mechanism 220. Because the thicknesses of different positions of the box body are different, the average wall thickness of the box body is between 2mm and 4mm, the structural strength of the box body and the weight relation of the box body can be well balanced, and the average wall thickness of the lower box body is selected as far as possible while a certain structural strength is maintained. The average wall thickness of the case may be specifically 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm or the like.

The box body of the traditional reduction gearbox adopts a layer of metal shell, and in order to ensure the structural strength of the shell, the wall thickness of the metal shell is large usually, so that the weight of the shell is large, and further the weight of the whole machine is also large. In view of this problem, the inventors have considered that if the wall thickness of the metal casing is reduced in order to reduce the weight of the entire machine, the structural strength of the casing is affected; if the material of the shell is changed in order to reduce the weight of the whole machine, the structural strength of the shell is still affected. Therefore, the inventor finds that the traditional single-layer shell can be changed into a double-layer shell, so that the structural strength of the shell can be ensured, and the weight of the whole machine can be reduced.

Thus, the housing is provided as a metal housing, and the electric hammer 200 further includes a plastic case 290 for housing the metal housing. The metal box body of the reduction box is made thinner than the wall thickness of the traditional metal shell, a layer of plastic shell 290 made of plastic is arranged outside the metal box body, and the sum of the weight of the metal box body and the plastic shell 290 is smaller than that of the traditional metal shell, so that the aim of reducing the weight of the whole machine can be achieved. Since the impact force is large when the electric hammer 200 operates, the double-layered case can also secure sufficient structural strength to cope with the impact force.

In this embodiment, the metal case includes a front housing 280 at least partially housing the cylinder 222, a middle housing 282 covering the gear train, and a lower housing 284 coupled to the middle housing. The front housing 280 is disposed at a side adjacent to the cartridge 160, and the middle housing 282 is coupled at one end to the front housing 280 and at the other end to the lower housing 284. The lower housing 284 is disposed between the middle housing 282 and the motor 210, and the lower housing 284 has three receiving grooves for receiving the transmission shafts and the motor shafts of the first transmission mechanism 230 and the second transmission mechanism 240, respectively. The front case 280, the middle case 282, and the lower case 284 may be partially integrally formed or may be spliced. For example, the front case 280 may be integrally formed with the middle case 282 and then joined to the lower case 284, or the middle case 282 may be integrally formed with the lower case 284 and then joined to the front case 280, or the front case 280, the middle case 282, and the lower case 284 may be separately joined, or the front case 280, the middle case 282, and the lower case 284 may be integrally formed. The gear train refers to at least part of the first transmission 230 and the second transmission 240. The front housing 280, middle housing 282, and lower housing 284 are sealingly engaged, and are removably attached to facilitate servicing of the internal components. For example, the front case 280 and the middle case 282 are sealed by a gasket or a sealant, and locked by a pin, a snap, or a screw. As is the case between middle housing 282 and lower housing 284. When the air cylinder needs to be maintained, the air cylinder can be taken out for maintenance only by disassembling the locking piece between the front shell 280 and the middle shell 282; when maintenance of the gear train is required, the gear train can be removed for maintenance by simply opening the retaining member between the middle housing 282 and the lower housing 284.

Furthermore, the metal box body is made of magnesium alloy or aluminum alloy. The magnesium alloy and the aluminum alloy have low density, and are lighter than iron, copper and other materials under the condition of the same volume, so that the weight of the reduction gearbox can be reduced, and the weight of the whole machine is reduced. The reduction gearbox can be made by casting.

As a specific embodiment, the front case 280, the middle case 282, and the lower case 284, which constitute the metal case, are made of magnesium alloy or aluminum alloy, and the weight of the front case 280, the middle case 282, and the lower case 284 is reduced, thereby reducing the weight of the entire apparatus. At this time, the thicknesses of the different housings may be determined according to the difference of the bearing force and the supporting force.

As another specific example, the front housing 280, the middle housing 282, and the lower housing 284 may be made of magnesium alloy or aluminum alloy. In this case, the distribution of the shells made of different materials can be determined according to the difference between the bearing force and the supporting force.

As still another specific example, the front case 280, the middle case 282, and the lower case 284 may be made of a magnesium alloy or an aluminum alloy. At this time, the distribution of the shells made of different materials is determined according to the difference of the bearing force and the supporting force.

Further, the plastic housing 290 has an average wall thickness of 2.5 mm. The inventor researches and discovers that when the average wall thickness of the plastic shell 290 is set to be 2.5mm, the structural strength of the shell and the weight of the shell achieve a good balance effect, the structural strength of the shell is guaranteed, the weight of the shell is reduced, and the weight reduction effect of the whole machine is good.

In some embodiments, the ratio of the number of times the ram 226 impacts the ram 228 per unit time to the number of rotations of the sleeve 250 is between 3.5 and 4. Specifically, the number of the carbon atoms may be 3.5, 3.6, 3.7, 3.75, 3.8, 3.9, 4.0, or the like. The ratio of the number of times the ram 226 impacts the ram 228 per unit of time to the number of revolutions of the sleeve 250 may be referred to as the hammer-to-drill ratio, or may be understood as the ratio of the number of hammering times of the work head per unit of time to the number of revolutions of the work head. The inventors have found that by selecting an appropriate hammer-to-drill ratio, the surface of the workpiece can be cut uniformly, and the working efficiency of the electric hammer 200 can be improved. Within this range, the electric hammer 200 can cut the surface of the workpiece uniformly, and a certain working efficiency is ensured.

Further, the ratio of the number of times the hammer 226 strikes the striker 228 per unit time to the number of rotations of the sleeve 250 is 3.827. The inventor has found that the cutting effect and the working efficiency of the electric hammer 200 reach a better state when the hammer-to-drill ratio is 3.827.

In some embodiments, the weight of the ram 226 is between 62g and 105g and the weight of the ram 228 is between 75g and 90 g. The inventor researches and finds that on the premise of selecting the inner diameter of the air cylinder 222, the weight of the ram 226 and the ram 228 is selected to be appropriate, so that the aim of balancing the hammering efficiency and the weight of the whole machine can be achieved. Consider that: when the weight of the ram 226 is too low, the elastic potential energy of the air spring formed between the inner wall of the cylinder 222 and the ram 226 is difficult to push the ram 226 to reciprocate, and the working efficiency of the electric hammer 200 is obviously reduced; when the weight of the hammer 226 is too high, the elastic potential energy of the air spring formed between the inner wall of the cylinder 222 and the hammer 226 and the elastic potential energy of the hammer 228 at the time of rebounding are easily disturbed, so that the hammer 226 and the hammer 228 are continuously seriously impacted, energy loss is caused, the working efficiency of the electric hammer 200 is reduced, and the comfort during operation is affected.

The weight of the striker 228 is adjusted accordingly to the weight of the ram 226. In this embodiment, the weight range of the hammer 226 and the weight range of the striker 228 can improve the working efficiency. The weight of the ram 226 may be, specifically, 62g, 66g, 70g, 74g, 78g, 82g, 83.5g, 86g, 90g, 94g, 98g, 102g, 105g, and the like. The weight of the striker 228 may be, specifically, 75g, 77g, 79g, 81g, 83g, 85g, 87g, 89g, 90g, or the like.

Further, the weight of the ram 226 is between 62g and 75g, and the weight of the ram 228 is between 80g and 85 g. As shown in the foregoing tables 1 to 3, in the range where the weight of the hammer 226 is 62g to 75g, the working efficiency of the electric hammer 200 is relatively high, and at the same time, the weight of the hammer 226 is relatively reduced, improving the convenience of operation. When the weight of the striker 228 is changed on the assumption that the weight of the hammer 226 is unchanged, the experimental contents are the same as those described above, and will not be described herein again, and it is verified through a lot of experiments that when the weight of the striker 228 is 80g to 85g, such as 80g, 81g, 82g, 82.5g, 83g, 84g,85g, etc., the working efficiency of the electric hammer 200 is relatively high, and at the same time, the weight of the striker 228 is relatively reduced, and the convenience of operation is improved. The whole machine is lighter in weight, the occupied space is relatively reduced, and the miniaturization and the lightness of the whole electric hammer 200 are realized.

In some embodiments, the stack length of the motor 210 is between 30mm and 35 mm. Wherein the stack length of the motor 210 is defined as the overlap length of the rotor and the stator. The stack length of traditional motor is generally 40mm and above, and occupation space is great relatively, and in this embodiment, through reducing the stack length of motor 210, reduce the occupation space of motor 210, and then reduce the weight of motor 210 to reduce the weight of complete machine. In the present embodiment, the weight of the motor 210 can be reduced by 50g to 100g relative to the stack length of the conventional motor.

Generally, the reduction of the stacking length of the motor leads to the reduction of the output power of the motor, the increase of the temperature of the motor and the reduction of the working efficiency. However, the inventors have found through research that: when the length of the motor is 30mm to 35mm, the output power and the temperature condition of the motor can meet the use requirement of the electric hammer 200 when the inner diameter of the air cylinder 222 is 25mm, so that the working efficiency of the electric hammer 200 can be ensured, and the weight of the electric hammer 200 can be reduced.

As shown in table 4, the stack length of the motor 210 in the range of 30mm to 35mm is shorter than that of the motor having the stack length of 40mm, so that the motor 210 can be selected in the range of the stack length smaller while the working efficiency is ensured, thereby reducing the weight of the motor 210 and the weight of the electric hammer 200. Specifically, it may be 30mm, 31mm, 32mm, 32.5mm, 33mm, 34mm, 35 mm.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. An electric hammer, comprising:

a motor having a motor shaft, the motor having a stack length of between 30mm and 35 mm;

the impact mechanism comprises a cylinder, a piston which is accommodated in the cylinder and reciprocates along a working axis, a hammer matched with the piston and a ram matched with the hammer, wherein the inner diameter of the cylinder is 25mm, and the working axis is perpendicular to the axis of the motor shaft;

the first transmission mechanism is matched with the motor shaft and provides impact force for the piston to move along the working axis;

the second transmission mechanism is matched with the motor shaft and provides driving force for the cylinder to rotate around the working axis;

the rotating sleeve is connected with the second transmission mechanism and is used for accommodating at least part of the working head and driving the working head to rotate;

the electric hammer comprises a reduction box, the reduction box comprises a box body and a gear train contained in the box body, the box body comprises a front shell at least partially containing the air cylinder, a middle shell covering the gear train, and a lower shell matched and connected with the middle shell.

2. An electric hammer according to claim 1 wherein the average wall thickness of the housing is between 2mm and 4 mm.

3. The electric hammer of claim 2, wherein the housing is a metal housing, the electric hammer further comprising a plastic housing for receiving the metal housing.

4. The electric hammer of claim 3, wherein the metal case is made of magnesium alloy or aluminum alloy.

5. An electric hammer according to claim 3, wherein the plastic housing has an average wall thickness of 2.5 mm.

6. The hammer of claim 1 wherein the ratio of the number of times the ram impacts the ram per unit time to the number of revolutions of the sleeve is between 3.5 and 4.

7. The electric hammer of claim 1, wherein the ram has a weight of between 62g and 105g and the ram has a weight of between 75g and 90 g.

8. The electric hammer of claim 7, wherein the ram has a weight of between 62g and 75g and the ram has a weight of between 80g and 85 g.

9. The electric hammer of claim 1, wherein the overall weight of the electric hammer is no greater than 4.2 kg.

10. The electric hammer according to claim 1, wherein the front housing is detachably connected with the middle housing, and the middle housing is detachably connected with the lower housing.

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