CN218253196U

CN218253196U - Reciprocating motion electric tool

Info

Publication number: CN218253196U
Application number: CN202221900797.7U
Authority: CN
Inventors: 戴伟
Original assignee: Nanjing Jiuchi Electromechanical Industry Co ltd
Current assignee: Nanjing Jiuchi Electromechanical Industry Co ltd
Priority date: 2022-07-23
Filing date: 2022-07-23
Publication date: 2023-01-10
Anticipated expiration: 2032-07-23

Abstract

The utility model relates to a reciprocating motion electric tool belongs to electric tool technical field. The tool comprises a motor arranged in a shell and a reciprocating motion output shaft extending out of one end of the shell, wherein the motor is in transmission connection with a crank wheel with an offset crank pin, the crank pin is hinged with one end of a connecting rod, and the other end of the connecting rod is hinged with the output shaft; the crank wheel is hinged with the crank shaft through a hinge pin, and the crank pin is hinged with the hinge hole and forms a sliding pair with the radial guide groove. The utility model discloses can make the unloaded stroke of electric tool operation absorb more rotatory inertial energy, resistance stroke because of releasing some rotatory inertial energy, compromise resistance stroke and unloaded stroke as a result, make reciprocating motion electric tool's inertia pass through the crank dead point and the performance of resistance stroke acting better, more be favorable to inhibiting the vibration simultaneously.

Description

Reciprocating motion electric tool

Technical Field

The utility model relates to a hand-held type electric tool, especially a reciprocating motion electric tool belongs to electric tool technical field.

Background

The reciprocating electric tool converts a rotational motion of a power source such as a motor into a reciprocating motion required for machining a workpiece by a mechanism such as a crank block. In order to suppress vibration and noise caused by imbalance in the mass of the reciprocating transmission mechanism, a counterweight balancing device is generally provided.

Chinese patent No. 201420301516.5 discloses an electric tool with a counterweight balancing device, which comprises a housing, a motor and a transmission mechanism. The transmission mechanism includes a driven gear driven by a motor. The driven gear is vertically positioned within the housing and has an upper portion and a lower portion. The transmission mechanism further includes a connecting rod connected to the driven gear to convert the rotational motion of the driven gear into a reciprocating motion, and an output shaft connected to the connecting rod to reciprocate relative to the housing to complete the cutting stroke and the return stroke. The drive mechanism further includes a counterweight coupled to the driven gear for rotation therewith. The weight moves through an upper portion of the driven gear during a cutting stroke of the output shaft and through a lower portion of the driven gear during a return stroke of the output shaft.

The counterweight devices so far are designed according to the no-load balance of the reciprocating mechanism, and the actual situation that the reciprocating electric tool often has operation resistance only in a single stroke cannot be considered, so that the resistance stroke and the no-load stroke are balanced by the same counterweight, and the balance cannot be considered necessarily, so that the vibration suppression effect is not balanced, and the operation resistance cannot be overcome.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: aiming at the defects in the prior art, the reciprocating electric tool which gives consideration to the balance effect of the resistance stroke and the no-load stroke counter weight is provided through structural improvement, so that the reciprocating electric tool is more convenient to operate and better in operation performance.

In order to achieve the above purpose, the utility model discloses reciprocating motion electric tool basic technical scheme does: the crank-type motor comprises a motor arranged in a shell and a reciprocating motion output shaft extending out of one end of the shell, wherein the motor is in transmission connection with a crank wheel with an offset crank pin, the crank pin is hinged with one end of a connecting rod, and the other end of the connecting rod is hinged with the output shaft; the crank pin is hinged with the hinged hole and forms a moving pair with the radial guide groove.

Because the utility model discloses broken through balancing weight and the coaxial rotatory traditional structure of crank, thereby make the balancing weight change for the angular velocity of crank and support and barycenter owing to there being eccentric and radial guide slot mechanism between the two and arouse the change of balancing weight inertia kinetic energy, as long as with eccentric angular position suitable set up in partial output shaft return direction one side, can make the unloaded stroke of electric tool operation absorb more rotatory inertia energy, the resistance stroke is because of releasing some rotatory inertia energy, resistance stroke and unloaded stroke have been compromise to the result, the performance that the inertia that makes reciprocating motion electric tool passes through crank dead point and resistance stroke work is better, more be favorable to inhibiting the vibration simultaneously.

Drawings

The present invention will be further described with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a first embodiment of the present invention.

FIG. 2 isbase:Sub>A schematic sectional view A-A of FIG. 1.

Fig. 3 is a schematic perspective exploded view of a reciprocating mechanism portion in the embodiment of fig. 1.

Fig. 4 is a schematic exploded perspective view of fig. 3 from another perspective.

Fig. 5 is a force analysis diagram of the counterweight mechanism in the embodiment of fig. 1.

FIG. 6 is an enlarged schematic view of the force analysis of FIG. 5.

Fig. 7 is a schematic perspective exploded view of a reciprocating mechanism according to a second embodiment of the present invention.

Fig. 8 is a schematic sectional structure diagram of a second embodiment of the present invention.

Detailed Description

Example one

The reciprocating electric tool of the present embodiment is actually a reciprocating saw, and is constituted as shown in fig. 1 to 4, the housing is constituted by a handle housing 1 at the rear and a gear housing 2 at the front, and the gear housing 2 is constituted by a left housing 2-L and a right housing 2-R which are opposed to each other. The handle part shell 1 is internally provided with a motor 3, a shaft sleeve 2-1 and an axial sliding groove 9 are fixed in the gear box body 2, and the front end of the shaft sleeve 2-1 extends out of an output shaft 5 supported by the shaft sleeve 2-1. A main shaft 3-2 of the motor 3 is in transmission connection with a large gear 4 serving as a crank wheel through a bevel gear 3-1 at the end, and the large gear 4 is hinged with one end of a connecting rod 7 and one end of an 8-shaped bracket 8 through a crank pin 6. The other end of the connecting rod 7 is hinged with the output shaft 5 constrained by the chute 9, thereby forming a crank block mechanism for reciprocating the output shaft.

The support shaft 11 as the rotation center of the support 8 is coaxial with the crank shaft 4-1 as the rotation center of the large gear 4, the support shaft 11 is supported in the inner hole of the eccentric boss 1-1 of the shell 1 through a needle bearing, the mounting hole of the counterweight block 10 is sleeved on the excircle of the eccentric boss 1-1 through the lining roller sleeve 10-2, and the excircle of the eccentric boss 1-1 has an eccentric distance of 0.5mm deviated to one side of the return direction of the output shaft relative to the inner hole, so that the rotation center of the counterweight block 10 is eccentric relative to the rotation center of the support 8.

The support 8 is provided with a hinged hole 8-2, the balancing weight 10 is provided with a radial guide groove 10-1, the crank pin 6 is hinged with the hinged hole 8-2 through the hinged hole and inserted into the radial guide groove 10-1 to form a moving pair.

In operation, as shown in fig. 5 and 6, C1 is the rotation center of the weight 10, C2 is the rotation center of the large gear 4, the distance between C1 and C2 is the eccentricity e, and the center distance between the crank pin 6 and C2 is R2. When the big gear 4 is driven by the motor to rotate at a constant speed, the linear speed is V at any moment and the direction is vertical to R2 because the crank pin 6 is hinged on the big gear 4. At this time, the contact point of the balance block 4 with the crank pin 6 moves synchronously with the crank pin 6, the speed of the contact point is also V, and the size and the direction of the contact point are the same as those of the crank pin 6. The velocity V of the contact point is actually synthesized from two vector velocities: rotating with the weight 10 about the center C1, a linear velocity V1 perpendicular to R1, and a linear velocity V2 sliding along the radial guide groove 10-1. According to the vector analysis, the following results are obtained: the rotating linear velocity V1= V × cos β = R2 × ω 2 × cos β of the weight 10, where β is a function of α, α is an angle between R2 and a line connecting C1 and C2, and ω 2 is the angular velocity of the large gear 4. This results in an angular velocity ω 1=v1/R1= R2 ×. ω 2 ×. Cos β/R1 of the counterweight 10, where R1 ² =e ² +R2 ² -2 × e × r2 × cos (pi- α). In summary, it can be seen that the weight 10 is not uniform with the gear 4The speed is changed and the rotation is changed in speed with the change of the angle alpha. The kinetic energy of the balance weight J =1/2*I omega 2 can be known by an energy formula ² And I is the rotational inertia of the balance block, the structure causes the kinetic energy of the balance block to change along with the change of the angular velocity omega 2, and the energy storage and energy release effects are completed under the pushing action of the force of the crank pin 6. Referring to fig. 1, the pull-back stroke of the saw blade with reciprocating saw teeth cuts materials with high cutting resistance and requires high power; the opposite direction is the idle motion without sawing the material. The structure of this embodiment is through the relative off-centre of rotation of the centre of rotation of rational design balancing weight 10 and gear wheel 4, has realized: during the no-load stroke, the actual load of the motor is light, the rotating speed of the counterweight block 10 is increased, and the kinetic energy is increased, so that the abundant energy of the motor is accumulated; during the sawing stroke, the rotating speed of the balancing weight 10 is reduced, accumulated energy is released, and the sawing efficiency is improved. For a long time, because the difference of two strokes is ignored, the simple balance structure of coaxial synchronous rotation of the balancing weight and the large gear is adopted, scientific kinetic energy distribution cannot be realized, and the reduction of the motor burden and the increase of the cutting efficiency are not facilitated.

Example two

The present embodiment is also a reciprocating saw, the basic structure of which is the same as the first embodiment, except that as shown in fig. 7 and 8, the two ends of the support shaft 11 are coaxial sections 11-1, 11-2, which are supported on the left case 2-L and support the rotating center hole of the support 8 through a needle bearing, the middle of the support shaft 11 is an eccentric section 11-M, the mounting hole of the counterweight 10 is sleeved on the eccentric section 11-M through a lining roller sleeve 10-2, and since the coaxial sections 11-1, 11-2 at the two opposite ends of the excircle of the eccentric section 11-M have an eccentric distance of 0.5mm deviated from one side of the return direction of the output shaft, the rotating center of the counterweight 10 is eccentric relative to the rotating center of the support 8.

The working principle and the action effect of this embodiment are the same as those of the first embodiment, and are not described in detail.

In addition to the above embodiments, the present invention may have other embodiments. All the technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope claimed by the present invention.

Claims

1. A reciprocating power tool comprising a motor housed in a housing and a reciprocating output shaft extending from one end of the housing, the motor being drivingly connected to a crank wheel having an offset crank pin, the crank pin being hinged to one end of a connecting rod, the other end of the connecting rod being hinged to the output shaft;

the method is characterized in that: the crank pin is hinged with the hinged hole and forms a moving pair with the radial guide groove.

2. The reciprocating power tool of claim 1, wherein: the support uses the support shaft as the center of rotation, the support shaft supports in the eccentric boss hole of casing, the mounting hole suit of balancing weight is in the excircle of eccentric boss, the excircle of eccentric boss has the eccentricity relative to its inner bore.

3. The reciprocating power tool of claim 2, wherein: the support shaft is supported in an inner hole of an eccentric boss of the shell through a bearing, and a mounting hole of the balancing weight is sleeved on an excircle of the eccentric boss through an inner lining rolling sleeve.

4. The reciprocating power tool of claim 1, wherein: the support uses a support shaft as a rotation center, two ends of the support shaft are supported on a coaxial section of the shell, the middle of the support shaft is an eccentric section, a mounting hole of the balancing weight is sleeved on the eccentric section, and the coaxial sections at two opposite ends of the excircle of the eccentric section have an eccentric distance.

5. The reciprocating power tool of claim 4, wherein: two ends of the support shaft are respectively supported on the shell and the rotating center hole of the support through a bearing, and the mounting hole of the balancing weight is sleeved on the eccentric section through a lining rolling sleeve.

6. The reciprocating power tool of claim 2 or 4, wherein: the eccentricity is deviated to one side of the return direction of the output shaft.

7. The reciprocating power tool of claim 6, wherein: the crank pin passes through the hinging hole of the bracket to be hinged with the bracket and is inserted into the radial guide groove to form a moving pair.

8. The reciprocating power tool of claim 6, wherein: the shell is composed of a handle part shell at the rear part and a gear box body at the front part, and the gear box body is composed of a left box body and a right box body which are oppositely combined.

9. The reciprocating power tool of claim 8, wherein: a motor is arranged in the handle part shell, a shaft sleeve and an axial sliding groove are fixed in the gear box body, and the front end of the gear box body extends out of an output shaft supported by the shaft sleeve; a main shaft of the motor is in meshed transmission connection with the crank wheel through a bevel gear at the end, and the crank wheel is hinged with one end of the connecting rod and one end of the 8-shaped bracket through the crank pin; the other end of the connecting rod is hinged with the output shaft constrained by the sliding chute to form a crank block mechanism which enables the output shaft to reciprocate.