CN100406208C

CN100406208C - Cooling mechanism for a power tool

Info

Publication number: CN100406208C
Application number: CNB2005101358151A
Authority: CN
Inventors: 克劳斯-迪特尔·阿里希; 埃哈德·本纳; 曼弗雷德·德罗斯特; 乌韦·内梅茨; 马丁·左伊卡; 米夏埃尔·G·孔茨
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 2004-12-23
Filing date: 2005-12-23
Publication date: 2008-07-30
Anticipated expiration: 2025-12-23
Also published as: DE602005010037D1; GB0510930D0; GB0510936D0; GB0510934D0; CN1792567A; GB0510940D0; ATE409554T1; CN100450726C; CN1792563A; GB2421700A; GB2421460A; CN100515687C; CN1792565A; CN100434240C; CN1807027A; GB2421459A; CN1792566A; GB2421461A; CN1792562A; GB2421462A

Abstract

A cooling system for a dynamic tool comprises a motor cooling fan arranged on the axis of a motor (634) and between an upper enerizing coil and a lower commutator. A transmitting casing (680) basically encloses a transmitting mechanism. During the operation of the dynamic tool, the cooling fan is driven by the motor, sucks air to axially pass through the motor and discharges air from a hole formed in the casing of the motor (634). Therefore, air can be sucked in via an air hole (669) formed at the top of a tool casing (622) and the lateral side of the casing (622), and between the casing (622) and a battery stack (630). Cool air flows along the path indicated by a cooling air arrow (671) and passes through the tool casing (622). The cool air flows on the outside of the driving casing (680) but on the inner side of the tool casing (622), so that the air does not pass through the transmitting mechanism. Multiple motor holes (635) are formed in the casing of the motor (634) so that the cool air can enter the motor to cool the motor.

Description

The power tool cooling system

Technical field

The present invention relates to be used for the cooling system of power tool, and especially but be not to relate to the cooling system that is used for hammer drill specially.

Background technology

Hammer drill is usually can be with the power tool of three kinds of operation mode.Hammer drill has can be with the cutter head of hammering pattern, rotary mode and the work of impact rotation integrated mode.

Hammer drill, the same with a lot of power tools, in use produce big calorimetric.Particularly, the motor of hammer drill produces a large amount of heat and needs cooling.Prior art hammer drill cooling system is known, and wherein air is sucked in the shell of this hammer drill to cool off this motor.The shortcoming of prior art hammer drill cooling system is, other materials that air in this instrument of inspiration forms in the time of may including dust and instrument use, if these dust and foul enter in the movable part of transmission mechanism, may the damage of this power tool will be caused.

Summary of the invention

The preferred embodiments of the present invention are intended to overcome above-mentioned shortcoming of the prior art.

According to the present invention, a kind of power tool is provided, this power tool comprises:

Shell for user's grasping;

Be arranged on the motor in this shell, this motor has the output shaft of the operation element that is used to activate this instrument;

Be suitable for being used to make air to flow through this motor by this motor-driven cooling fan; And

Be suitable for responding the rotation of described output shaft to activate the transmission mechanism of described operation element, and this power tool has the inner casing that is used for supporting at this shell this transmission mechanism, this shell has at least one air intake and at least one air outlet slit, and this cooling fan is suitable for making air to flow to described motor from least one inlet between this inside and outside shell.

Has the power tool that is used for supporting the inner casing of transmission mechanism by providing in this housings; this shell has at least one air intake, at least one air outlet slit; and be suitable for making air to flow to the cooling fan of motor from least one inlet between the described inside and outside shell; the advantage of doing like this is; this motor is cooled, and protects this transmission mechanism to avoid causing the evil of the dust that transmission mechanism damages simultaneously.However, this transmission mechanism is cooled to a certain degree when air flows through this inner casing, and this inner casing is as the radiator that distributes the heat that is produced by the transmission mechanism that is positioned at it.

This motor can comprise electric machine casing, and this electric machine casing has and a plurality ofly is used to allow air to flow through the hole of this motor.This has the advantage that strengthens the motor cooling.

Preferably, this electric machine casing is connected in this inner casing to prevent the sealing means that air flows between this electric machine casing and this inner casing.Easy like this output shaft is connected in this transmission mechanism, guarantees that simultaneously preventing to be included in the airborne dust and the foul that flow through this motor enters transmission mechanism, it may damage its movable part in transmission mechanism.

This power tool can also comprise: at least one is arranged on the air intake of this upper surface of outer cover, at least one is arranged on the air intake on this shell side, and at least one be arranged on this shell, the air intake of the separable battery pack in contiguous the use.Make (from all directions) to flow through the air capacity maximum on this inner casing surface like this, to help the heat radiation cooling effect of this inner casing.

In a preferred embodiment, this cooling fan is arranged between the magnet exciting coil and commutator of this motor.The advantage of doing like this is to guarantee that cold air not only flows through the magnet exciting coil of this motor but also flows through commutator, to strengthen the cooling of motor.

This power tool can also comprise that at least one is arranged on this shell, is arranged on this shell at the air outlet slit of the front portion of motor and at least one, the air outlet slit of the separable battery pack in contiguous the use.

In a preferred embodiment, this power tool is a hammer drill.

Description of drawings

With way of example rather than with the meaning of any restriction the preferred embodiments of the present invention are described below with reference to the accompanying drawings, wherein:

Fig. 1 is the partial cut-away perspective view of the driving mechanism of hammer drill prior art;

Fig. 2 is the viewgraph of cross-section of the driving mechanism of Fig. 1;

Fig. 3 is the perspective view of the hammer drill of first embodiment of the invention;

Fig. 4 is the hammer drill side viewgraph of cross-section of Fig. 3;

Fig. 5 is the Zoom Side viewgraph of cross-section of the hammer drill part of Fig. 4;

Fig. 6 is that the piston drive mechanism part of Fig. 3 is excised perspective view by the part of position, back at it;

Fig. 7 is 1/4th parts excision perspective views that move back and forth the piston drive mechanism part of circulation time Fig. 3 that advance from position shown in Figure 6;

Fig. 8 advances half cycles to its part excision perspective view of the piston drive mechanism part of Fig. 3 during forward position from position shown in Figure 6;

Fig. 9 is the side viewgraph of cross-section that is used for the hammer piston driving mechanism of second embodiment of the invention;

Figure 10 is the enlarged cross-sectional view along the A-A line intercepting of Fig. 9;

Figure 11 is the side viewgraph of cross-section of the hammer drill part of third embodiment of the invention;

Figure 12 is that for clarity sake some parts with this transmission mechanism remove along the viewgraph of cross-section of the B-B line intercepting of Figure 11;

Figure 13 is the viewgraph of cross-section along the C-C line intercepting of Figure 12;

Figure 14 is the side viewgraph of cross-section of the hammer drill of fourth embodiment of the invention;

Figure 15 a is the perspective view that the right side half clam shell of two parts transmission housing of the hammer drill of fifth embodiment of the invention is seen from the outside;

Figure 15 b is the side view in the half clam shell outside of Figure 15 a;

Figure 15 c is the perspective view of the half clam shell inboard of Figure 15 a;

Figure 15 d is the side view of the half clam shell inboard of Figure 15 a;

Figure 15 e is the front view of half clam shell of Figure 15 a;

Figure 15 f is the viewgraph of cross-section along the A-A line intercepting of Figure 15 d;

Figure 15 g is the viewgraph of cross-section along the B-B line intercepting of Figure 15 d;

Figure 15 h is the viewgraph of cross-section along the F-F line intercepting of Figure 15 b;

Figure 16 a is the perspective view of seeing from the outside corresponding to a left side half clam shell of the right side half clam shell of Figure 15 a to Figure 15 h;

Figure 16 b is the side view in the half clam shell outside of Figure 16 a;

Figure 16 c is the perspective view of the half clam shell inboard of Figure 16 a;

Figure 16 d is the side view of the half clam shell inboard of Figure 16 a;

Figure 16 e is the front view of half clam shell of Figure 16 a;

Figure 16 f is the viewgraph of cross-section along the A-A line of Figure 16 d;

Figure 16 g is the viewgraph of cross-section along the B-B line intercepting of Figure 16 d;

Figure 16 h is the viewgraph of cross-section along the F-F line intercepting of Figure 16 d;

Figure 17 is the inboard perspective view that amplifies of half clam shell of Figure 16;

Figure 18 is the part excision top view of the hammer drill part that combines of half clam shell with Figure 15 and Figure 16;

Figure 19 is the part excision perspective view of the hammer drill part of Figure 18;

Figure 20 is the viewgraph of cross-section of this piston drive mechanism opposite side;

Figure 21 is the viewgraph of cross-section of prior art piston drive mechanism;

Figure 22 is the partial cross-sectional view that the piston drive mechanism of Figure 21 amplifies;

Figure 23 is the viewgraph of cross-section along the V-V line of Figure 22;

Figure 24 a is the viewgraph of cross-section of the hammer drill hollow piston of sixth embodiment of the invention;

Figure 24 b is the side perspective view of the hollow piston of Figure 24 a;

Figure 24 c is the top view of the hollow piston of Figure 24 a;

Figure 24 d is the front view of the hollow piston of Figure 24 a;

Figure 25 is the rearview of piston drive mechanism that includes the hollow piston of Figure 24 a to Figure 24 d that is installed on the main shaft;

Figure 26 is the rear view of the piston drive mechanism of Figure 25;

Figure 27 is the side view of the hammer drill of seventh embodiment of the invention; And

Figure 28 is the hammer drill side viewgraph of cross-section of Figure 27.

The specific embodiment

With reference to figure 3, be that the hammer drill of power comprises tool housing 22 and is used for fixing the dop 24 of drill bit (not shown) with the battery.This tool housing 22 is formed with handle 26, and this handle has the trigger 28 that is used to start this hammer drill.Battery pack 30 is connected in the bottom of this tool housing 22 removably.Model selection knob 32 is set, is used for selecting between a hammering pattern, a rotary mode and the hammering rotation integrated mode in the drill bit operation.

With reference to figure 4, motor 34 is arranged in this tool housing 22 and has rotating output shaft 36.Pinion 38 is formed on the end of this output shaft 36, and this pinion 38 meshes with first driven wheel 40 of rotary drive mechanism and second driven wheel 42 of hammering driving mechanism.

This rotary drive mechanism is described below.First bevel gear 44 is driven by first driven wheel 40.This

first bevel gear

44 and 46 engagements of second bevel gear.This second bevel gear 46 is installed on the main shaft 48.The rotation of second bevel gear 46 passes to this main shaft 48 via the clutch mechanism that comprises overload spring 88.This main shaft 48 is mounted to by spherical ball bearing race 49 around its longitudinal axis rotation.The drill bit (not shown) can insert in this dop 24 and be connected in the front end 50 of this main shaft 48.When hammer drill 20 is in rotary mode or hammering rotation integrated mode, this main shaft 48 and drill bit rotation.This clutch mechanism prevents that excessive torque from passing to motor 34 from drill bit and main shaft 48.

The hammering driving mechanism will be described below.The pinion 38 of motor output shaft 36 and the engagement of second driven wheel 42 make the rotation of this second driven wheel 42 cause the rotation of crank disc 52.Crank-pin 54 is driven and slidably engages the cylindrical bearing 56 that is arranged on hollow piston 58 ends by this crank disc 52.This hollow piston 58 slidably is installed in the main shaft 48, makes the rotation of this crank disc 52 cause that hollow piston 58 moves back and forth in this main shaft 48.Ram and 60 slidably be arranged in the hollow piston 58.Just as well known for one of skill in the art, as the result that mattress 93 expands and shrinks, the reciprocating motion of this hollow piston 58 causes rams 60 with these hollow piston 58 reciprocating motions.When this hammer drill during with the operation of hammering pattern or hammering rotation integrated mode, 60 the reciprocating motion of raming causes to ram 60 impacts hit pieces 62, and hit piece is delivered to impact the drill bit (not shown) in the dop 24 again.

Mode shift mechanism comprises first and

second drive sleeve

64,66, it optionally is connected in this first bevel gear 44 and crank disc 52 with this first and second driven

wheel

40,42 respectively, so that the user can be selected between a hammering pattern, a rotary mode or hammering rotation integrated mode.This mode shift mechanism is the theme of UK Patent Application 0428215.8.

Transmission mechanism comprises rotary drive mechanism, hammering driving mechanism and mode shift mechanism.This transmission mechanism is arranged on transmission housing 80 the insides.This transmission housing 80 is support motor 34 also.This transmission housing is made of half clam shell of two durable plastic material or cast metal, and this two and half clam shell pushes O shape ring 82 between them.This O shape is encircled 82 seal casinghousings 80, enters this transmission housing and damages the moving component of this transmission mechanism to prevent dust and foul.

This transmission housing 80 slidably is installed on the closed slide (not shown) of tool housing 22 the insides, and is rested on the tool housing 22 by first and second shock-absorbing

springs

84 and 86 that are arranged on the rear end.Therefore this transmission housing 80 can be with respect to less amount of these tool housing 22 motions, to pass to user's vibration in this hammer drill 20 operating periods minimizing.This first and second shock-absorbing

spring

84 and 86 spring constant are chosen as, when this hammer drill 20 uses under normal operating condition, this transmission housing 80 slide into its forward and backward between the limit of sports record roughly in the middle of point.This point is an equalization point, equals to be placed on this hammer drill 20 on the workpiece and to be leaned against on this tool housing 22 and the power backward that produces on this transmission housing 80 by the user at this biasing force forward of putting this shock-absorbing

spring

84 and 86.

With reference to figure 5, will describe the hammering driving mechanism in detail below.Crank-pin 54 comprises the cylindrical link member 68 that is rigidly connected to part ball bearing 70.This part ball bearing 70 is slidably to be arranged in the cup shaped recess 72 that is formed in this crank disc 52 with rotatable mode.This cup shaped recess 72 has roughly hemisphere portion 72b of top cylindrical part 72a and bottom.This top cylindrical part 72a and lower hemispherical part 72b have same maximum gauge, and this maximum gauge is a bit larger tham the maximum gauge of part ball bearing 70.As a result, this part ball bearing 70 can be easy to insert in this cup shaped recess.This crank-pin 54 can pivot, rotate and slide vertically with respect to this crank disc, and this part ball bearing still remains in the scope of this cup shaped recess 72 simultaneously.

This cylindrical link member 68 slidably is arranged in the cylindrical bearing 56 that is formed in these hollow piston 58 ends.Force of sliding friction in this cup shaped recess 72 is a bit larger tham the force of sliding friction in this cylindrical bearing 56.Therefore, when this part ball bearing swung back and forth in this cup shaped recess, this cylindrical link member 68 slided up and down in this cylindrical bearing 56.Cylindrical shaft ring 74 is around the cylindrical link member 68 of this crank-pin 54, and can slide between the upper position of these cylindrical bearing 56 downsides against the lower position of these part ball bearing 70 upper surfaces and its at it.This axle collar spare 74 is a kind of prevent means, and it limits the motion of this part ball bearing 70 towards this cylindrical bearing 56, makes this crank-pin 54 and its part ball bearing 70 can not break away from fully and the engaging of this cup shaped recess 72.This cylindrical collar 74 can be installed on this crank-pin 54 after forming this crank disc 52 and crank-pin 54 assemblies.

With reference to figure 6 to Fig. 8, when this crank disc 52 along counter-clockwise direction when stand up position shown in Figure 6 rotates to position shown in Figure 7, can see that crank-pin 54 pushes away this hollow piston 58 forward and to lopsidedness.When crank-pin 54 tilts, this cylindrical link member 68 in this cylindrical bearing 56 to lower slider.Thereby shift this hollow piston 58 onto it during forward position when crank disc 52 rotates to Fig. 8 from the position of Fig. 7 position, this crank-pin 54 is in upright position again, and the cylindrical link member 68 of this crank-pin 54 upwards slides in this cylindrical bearing 56.Can see,, can prevent that this crank-pin 54 from moving too far and the engaging of disengaging and this crank disc 52 in this cylindrical bearing by this axle collar spare 74 last side engagement with downside and this part ball bearing 70 of this cylindrical bearing 56.Therefore, do not need interference fit to engage with this crank disc, simplified the assembling of this driving mechanism so greatly to keep this crank-pin.

The hammer drill of second embodiment of the invention is shown in Fig. 9 and Figure 10, and the parts identical with the embodiment of Fig. 3 to Fig. 8 are with same but increase by 100 Reference numeral and represent.

Crank-pin 154 has the structure same with the embodiment of Fig. 3 to Fig. 8.But in the embodiment of Fig. 9 and Figure 10, this axle collar spare 176 is helical springs.Pad 178 is arranged between this axle collar helical spring 176 and this cylindrical bearing 156.This axle collar helical spring 176 has additional advantage, and promptly it is biased into the part ball bearing 170 of this crank-pin 154 with the cup shaped recess 172 of this crank disc 152 and engages, so this part ball bearing even can not partly move and break away from this crank disc 152.

The hammer drill of third embodiment of the invention is shown in Figure 11 to Figure 13, with the embodiment common means of Fig. 3 to Fig. 8 with same but increase by 200 Reference numeral and represent.

This transmission housing 280 is made of half clam shell of two durable plastic material or cast metal material.This two and half clam shell is clipped in O shape ring 282 between them and pushes this O shape ring.This transmission housing 280 is supported by first and second shock-absorbing

springs

284 and 286 in its back-end.This transmission housing 280 also is installed on the parallel orbit (not shown) that is arranged on these tool housing 222 the insides, makes that this transmission housing 280 can be along the direction of these main shaft 248 longitudinal axis with respect to these tool housing 222 front and back less distance of sliding.

Shock-absorbing

spring

284 and 286 spring constant are chosen to, when this hammer drill uses under normal operating condition, make this transmission housing 280 slide into its forward and backward between the limit of sports record roughly in the middle of point.This point is an equalization point, and the biasing force forward in this shock-absorbing spring 284 on this aspect and 286 equals to be placed on this hammer drill 220 on the workpiece and to be leaned against on this tool housing 222 and the power backward that produces on this transmission housing 280 by the user.

The front end of this transmission housing 280 has local tapering part 290 roughly, and it is resisted against and is formed on corresponding local tapering part 292 on this tool housing 222.This part tapering part 290 and 292 and the longitudinal axis of this main shaft 248 form an about angle of 15 °.The interface that is formed by this part tapering part 290 and 292 forms a retainer, and when this hammer drill 220 was in the inoperation state, this transmission housing 280 rested on this tool housing 222 at this retainer place.When this hammer drill 220 uses under normal operating condition, a gap appears between the surface of this part tapering part 290 and 292, this gap helps to reduce axially and oscillation crosswise, otherwise these vibration meetings directly pass to the user who holds this hammer drill 220 from the tool heads (not shown).Certainly, when this transmission housing overcomes the bias voltage of this shock-absorbing spring 284 and 286 when mobile backward, this gap can increase slightly.This help to reduce when the user applies bigger pressure forward to this hammer drill 220, may increase axially and oscillation crosswise.But this gap is enough little, and this hammer drill 220 and transmission housing 280 always can suitably be controlled by the interface between this part tapering part 290 and 292 by the user, and this interface keeps this transmission housing 280 and 222 alignment of this tool housing.

The hammer drill of fourth embodiment of the invention is shown in Figure 14, and the parts identical with the embodiment of Fig. 3 to Fig. 8 are with same but increase by 300 Reference numeral and represent.

This hammer drill 320 has tool housing 322.In this embodiment, this transmission housing 380 is made of three housing parts.The first roughly L shaped housing parts 380a holds the transmission mechanism except that the front end 348a of first and second gears 340,342 and main shaft 348.The bottom of this first housing parts 380a is installed on the second housing parts 380b, and the O shape ring 382a that wins is stuck between these two parts, enters to prevent dust and foul.This second housing parts 380b remains on the bottom of this transmission mechanism the inside of this first housing parts 380a and holds this first and two gear 340,342.This second housing parts 380b has motor delivery outlet 390, motor output shaft 336 is entered in this transmission housing the inside, and make pinion 338 can drive first and second gears 340,342 of this transmission mechanism.The 3rd housing parts 380c is installed in the front end of this first housing parts 380a, makes the 2nd O shape ring 382b be stuck between these two parts to prevent that dust and foul from entering.The 3rd housing parts 380c remains on first housing parts 380a the inside with the front portion of this transmission mechanism and holds the front end 348a of main shaft.

This first roughly L shaped housing parts 380a makes transmission mechanism can be assembled in this first housing parts 380a the inside from its two ends fully.For example hollow piston and spindle assemblies can insert the front end of this first drive shell body portion 380a, this first housing parts 380a can rotate 90 ° then, and each gear and mode shift mechanism can and fall into correct position by the bottom insertion, to engage this main shaft 348 and hollow piston 358.This second and the 3rd drive shell body portion 380b and 380c can be installed on this first drive shell body portion 380a then, so that cover the openend of this first drive shell body portion 380a.

This first drive shell body portion 380a can be as the standard stand (the hammering driving mechanism, rotary drive mechanism and the mode shift mechanism that comprise standard) of some kinds of power tools, and the second and the 3rd drive shell body portion 380b and 380c can change, with motor and the main shaft that adapts to different size.

The hammer drill of fifth embodiment of the invention has the transmission housing that is shown in Figure 15 to Figure 20, and the parts identical with the embodiment of Fig. 3 to Fig. 8 are with same but increase by 400 Reference numeral and represent.

With reference to Figure 15 and Figure 16, the transmission housing is made of the right side half clam shell 421a and left half clam shell 421b, and this right side half clam shell 421a and left half clam shell 421b are formed with injection moulding by senior strong plastics.Each

half clam shell

421a, 421b have a plurality of screwed hole 423a, the 423b that is suitable for admitting the screw (not shown) respectively, make

half clam shell

421a, 421b to combine, and seal the transmission housing of this transmission mechanism with formation.

This two housing sections is suitable for keeping all members of this transmission mechanism, and various recesses are molded on half clam shell so that provide support for these members.For example, the shape of the first driven

wheel recess

427a, 427b is made and is suitable for supporting this first driven wheel 40.

Motor support section

425a and 425b are suitable for supporting and local top of sealing this motor 34.

This transmission housing slidably is installed on the pair of guide rails (not shown) in this tool housing 22.Because the inside and user that this transmission housing is arranged on this tool housing 22 can't see, therefore can be with this transmission housing of senior strong constructed in plastic material.Such material is because its unengaging color and quality are unsuitable for being used for the outside of power tool usually.Senior strong plastics have vibration and the noise damping property better than metal usually.The ribs (not shown) can be molded in the plastics to strengthen the intensity of this transmission housing.

With reference to Figure 15 to Figure 20, each

half clam shell

421a and 421b comprise overflow ducts 429a and the 429b that forms.This half clam shell also comprises corresponding ball distance ring support recesses 431a and 431b, and it is suitable for keeping ball distance ring 49, with supports main shaft 48.

Specifically referring to figs. 18 to Figure 20, this

half clam shell

421a and 421b cooperation are arranged on the ball distance ring 499 first transmission shell chamber 433 and the second transmission shell chamber 435 of a side separately with formation.This first transmission shell chamber 433 and the second transmission shell chamber 435 interconnect by passage 429a and 429b.The rear end of this hollow piston 458, cylindrical bearing 456, crank-pin 454 and crank disc 452 all are arranged in this first transmission shell chamber 433.The major part of this main shaft 448 and overload spring 458 are arranged in this second transmission shell chamber 435.The part of the main shaft 448 in this second transmission shell chamber has the passage 448a of circumference array.This passage 448a makes between this second transmission shell chamber 435 and the main shaft chamber 448b and can be communicated with, and this main shaft chamber 448b is positioned at these main shaft 448 the insides and in this

hollow plug

458 and 460 fronts of raming.

In the hammering pattern, this hollow piston 458 causes reciprocating motion by this crank disc 452.When this hollow piston 458 moved in this first transmission shell chamber 433, because the arrival of this hollow piston reduces the volume of this first transmission shell chamber, thereby the air pressure in this first transmission shell chamber 433 increased.Simultaneously, this hollow piston 458 and ram and 460 shift out this main shaft 448.Because this hollow piston and the volume that makes this main shaft chamber that leaves of raming increase, thereby this causes that the air pressure among the 448b of this main shaft chamber reduces.This second transmission shell chamber 435 is communicated with main shaft chamber 448b through passage 448a, and therefore the air pressure in the second transmission shell chamber 435 also reduces.This air pressure difference is balanced owing to air flows to into this second transmission shell chamber 435 and this main shaft chamber 448b by

overflow ducts

429a and 429b from the first transmission shell chamber 433.

On the contrary, when this hollow piston 458 entered this main shaft 448, because the volume of this first transmission shell chamber 433 is owing to leaving of this hollow piston increases, therefore the air pressure of the first transmission shell chamber 433 reduced.Simultaneously, because the volume of this main shaft chamber is owing to this hollow piston and the arrival of raming reduce, this causes that the air pressure among the 448b of main shaft chamber increases.As mentioned above, this second transmission shell chamber 435 is communicated with main shaft chamber 448b via passage 448a, so the air pressure in this second transmission shell chamber 435 also increases.This first transmission shell chamber 433 is balanced this air pressure difference because air refluxes into from this second transmission shell chamber 435 and main shaft chamber 448b by this

overflow ducts

429a and 429b.

As the result that the air among overflow ducts 429a and the 429b moves back and forth and circulates, during hollow piston 58 moved back and forth, the compression of air was eliminated, or significantly reduces.Therefore the hammering driving mechanism can do work owing to the air that compression retains or off-energy hardly.Increased the battery life of efficiency of motor and hammer drill like this.

The hammer drill of sixth embodiment of the invention has the hammering driving mechanism that is shown in Figure 24 to Figure 26, and the parts identical with the embodiment of Fig. 3 to Fig. 8 are with same but increase by 500 Reference numeral and represent.

With reference to Figure 24 to Figure 26, hollow piston 558 comprises cylindrical bearing 556, and it is suitable for holding crank-pin 554 and moves back and forth in main shaft 548 the insides so that cause this hollow piston 558.The (not shown) of raming slidably is arranged on this hollow piston 558 the insides, because the air spring effect that these hollow piston 558 the insides produce makes this ram and produces the hammering action.A plurality of vertical oncus 559 are formed on the external peripheral surface of hollow piston 558 of substantial cylindrical, and are long-pending with the contact surface between the main shaft 548 that reduces this hollow piston 558 and substantial cylindrical.The groove 561 of a plurality of convex curve shapes is formed in the gap between the described oncus.Described groove 561 defines the diameter slightly little cylinder of a diameter than these hollow piston 558 external peripheral surfaces.Therefore, described groove 561 is enough shallow, to hold the lubricant of normal viscosity during the whole normal running of this hammering driving mechanism.

This hollow piston 558 slidably is arranged on this main shaft 548 the insides.The rotation of crank disc 552 makes this crank-pin 554 act on cylindrical bearing 556, makes this hollow piston 558 move back and forth in these main shaft 548 the insides.This main shaft 548 also can be around these hollow piston 568 rotations.Be formed on the inner surface that vertical oncus 559 on these hollow piston 558 outer surfaces slidably engages this main shaft 548.Can see that the contact area between this hollow piston 558 and this main shaft 548 is owing to only being that described oncus 559 reduces with engaging of these main shaft 548 inner surfaces.Be retained in the friction that the lubricant 563 in the described groove 561 reduces between this main shaft 548 and this hollow piston 558.Air also can pass through between this hollow piston 558 and this main shaft through the space that is formed by groove 561, has therefore strengthened the cooling of this transmission mechanism.Air also helps air pressure in balanced this first and second transmissions shell chamber 433,435 of having discussed by described groove in the 5th embodiment.

Hammer drill with seventh embodiment of the invention of motor cooling system is shown in Figure 27 and Figure 28, and the parts identical with the embodiment of Fig. 3 to Fig. 8 are with same but increase by 600 Reference numeral and represent.

Hammer drill 620 comprises tool housing 622, wherein forms a plurality of passages 669.Described passage 669 is suitable for admitting the cold air from this hammer drill outside, perhaps hot-air is discharged from this hammer drill the inside.

With reference to Figure 28, the position of motor cooling fan (not shown) between the commutator (not shown) of the magnet exciting coil (not shown) on these motor 634 tops and bottom is arranged on the axis of this motor 634.Transmission housing 680 with above-mentioned two parts or three part types is sealed this transmission mechanism substantially.

At this power tool this cooling fan of operating period by this motor-driven.This cooling fan axially sucks air and passes this motor and radially discharge this air by the hole 675 in the shell 677 that is formed on this motor 634.This cooling fan aligns vertically with this hole 675, makes that air ratio is easier to radially discharge.This make air by be formed on these housing 622 tops, in the side of this housing 622 and the passage 669 between this housing 622 and this battery pack 630 suck.This cold air is crossed this housing 622 with path flow shown in the cold air arrow 671.Cold air still flows in the inside of this tool housing 622 around the outside of this transmission housing 680, makes air by this sealed transmission mechanism, enters to prevent foul.

A plurality of motors hole 635 is formed in the shell 677 of this motor 634, so that cold air can enter this motor to cool off this motor.Because the position of this cooling fan, cold air is inhaled into by the magnet exciting coil of this motor and engine commutator, makes each member be downward through this magnet exciting coil and the air that upwards flows through this commutator cools off separately.Hot-air is along being discharged by the preceding passage 669 of this shell front by the flow path shown in the hot-air arrow 673.Should align vertically with the hole 675 in these motor 634 shells 677 by preceding passage 669.Hot-air also can be discharged by the back passage 699 that is arranged between this tool housing 622 and the detachable battery group 630.

Describe embodiment with way of example rather than with any limited significance above it will be understood by those of skill in the art that, and in not breaking away from the scope of the present invention that is defined by the claims, can carry out various changes and modification.

Claims

1. power tool comprises:

Shell for user's grasping;

Be arranged on the motor in this shell, this motor has the output shaft of the operation element that is used to activate this instrument, and wherein this motor comprises electric machine casing, and this electric machine casing has and a plurality ofly is used to allow air to flow through the hole of this motor;

Be suitable for responding the rotation of described output shaft to activate the transmission mechanism of described operation element, and this power tool has the inner casing that is used for supporting at this shell this transmission mechanism, this shell has at least one air intake and at least one air outlet slit, and this cooling fan is suitable for making air to flow to described motor from least one inlet between described inner casing and the shell

It is characterized in that this electric machine casing is connected in this inner casing to prevent the sealing means that air flows between this electric machine casing and this inner casing.

2. according to the power tool of claim 1, also comprise: at least one is arranged on the air intake of this upper surface of outer cover, at least one is arranged on the air intake on this shell side, and at least one be arranged on this shell, the air intake of the separable battery pack in contiguous the use.

3. according to the power tool of claim 2, wherein said cooling fan is arranged between the magnet exciting coil and commutator of this motor.

4. according to the power tool of claim 1, wherein said cooling fan is arranged between the magnet exciting coil and commutator of this motor.

5. according to the power tool of claim 4, comprise also that at least one is arranged on this shell, is arranged on this shell at the air outlet slit of the front portion of motor and at least one, the air outlet slit of the separable battery pack in contiguous the use.

6. according to the power tool of claim 3, comprise also that at least one is arranged on this shell, is arranged on this shell at the air outlet slit of the front portion of motor and at least one, the air outlet slit of the separable battery pack in contiguous the use.

7. according to the power tool of claim 2, comprise also that at least one is arranged on this shell, is arranged on this shell at the air outlet slit of the front portion of motor and at least one, the air outlet slit of the separable battery pack in contiguous the use.

8. according to the power tool of claim 1, comprise also that at least one is arranged on this shell, is arranged on this shell at the air outlet slit of the front portion of motor and at least one, the air outlet slit of the separable battery pack in contiguous the use.

9. according to the power tool of aforementioned any one claim, wherein this power tool is a hammer drill.