CN217475000U

CN217475000U - Balance mechanism and reciprocating electric tool with same

Info

Publication number: CN217475000U
Application number: CN202220639649.8U
Authority: CN
Inventors: 麻立国; 周桂芳
Original assignee: Techtronic Cordless GP
Current assignee: Techtronic Cordless GP
Priority date: 2022-03-22
Filing date: 2022-03-22
Publication date: 2022-09-23
Anticipated expiration: 2032-03-22

Abstract

The utility model relates to a set up the balance mechanism in reciprocating motion formula electric tool, reciprocating motion formula electric tool include motor, reciprocating motion's instrument clamping part, with the actuating mechanism that motor and instrument clamping part drive are connected. The driving mechanism comprises a shell and a combined driving gear arranged in the shell, the combined driving gear is movably connected with the tool clamping part through an eccentric shaft arranged on the combined driving gear, and the motor drives the tool clamping part to reciprocate through the eccentric shaft. The balance mechanism comprises a balance mass body and a phase adaptation mechanism in driving connection with the balance mass body, the eccentric shaft drives the tool clamping part to reciprocate, and the combined driving gear drives the phase adaptation mechanism, so that the balance mass body is driven to reciprocate, the balance mechanism generates reciprocating momentum, and the reciprocating momentum is offset with at least one part of momentum generated by the reciprocating motion of the tool clamping part, and at least one part of vibration generated when the tool clamping part reciprocates is reduced.

Description

Balance mechanism and reciprocating electric tool with same

Technical Field

The utility model relates to a balance mechanism for reciprocating type electric tool to and reciprocating type electric tool who has this balance mechanism.

Background

Reciprocating power tools, such as power jigsaws, are widely used in construction and maintenance applications. A typical reciprocating power tool has a built-in motor and drive mechanism for converting the pivoting power of the motor into a linear power output that reciprocates the cutting tool. Since the parts performing the reciprocating movement have a certain mass, the reciprocating movement of these parts during operation inevitably generates vibrations and is transmitted to the user, which undoubtedly affects the stability and comfort when using the tool. Based on the problem of vibration, some known reciprocating power tools are provided with a balancing mechanism to reduce the vibration generated by the components performing the reciprocating motion. However, these balancing mechanisms are complex and take up much space, which undoubtedly adds to the bulk of the power tool. Moreover, these balancing mechanisms generate some excess momentum, which affects the damping effectiveness.

SUMMERY OF THE UTILITY MODEL

Therefore, there is a need to provide a new balancing mechanism to solve or at least alleviate the above technical problems.

The present invention is directed to a balance mechanism for a reciprocating electric tool, which can effectively reduce at least a part of vibration generated by a reciprocating motion of a tool holding portion.

According to one embodiment of the present invention, there is provided a balancing mechanism disposed in a reciprocating electric tool, the reciprocating electric tool comprises a motor, a tool clamping part which reciprocates and a driving mechanism which is in driving connection with the motor and the tool clamping part, the driving mechanism comprises a shell and a combined driving gear arranged in the shell, the combined driving gear is movably connected with the tool clamping part through an eccentric shaft arranged on the combined driving gear, the motor drives the tool clamping part to reciprocate through the eccentric shaft, wherein the combined driving gear comprises a first driving gear part and a second driving gear part which are concentrically arranged and synchronously rotate, the balance mechanism comprises a first balance mass body, a second balance mass body and a phase adaptation mechanism, wherein the first balance mass body and the second balance mass body are rotationally driven by the combined driving gear; the eccentric shaft drives the tool clamping part to reciprocate, the second driving gear part drives the phase adaptation mechanism to enable the second balance mass body to rotate opposite to the first balance mass body, momentum generated by the second balance mass body and perpendicular to the reciprocating direction of the tool clamping part is enabled to be mutually offset, reciprocating balance momentum generated by the balance mechanism and parallel to the reciprocating direction of the tool clamping part is offset with at least one part of reciprocating momentum generated by the reciprocating motion of the tool clamping part, and therefore at least one part of vibration generated when the tool clamping part reciprocates is reduced.

In one embodiment, the phase adaptation mechanism reverses the phase of the reciprocating momentum generated by the balancing mechanism to the phase of the reciprocating momentum generated by the tool gripping portion.

In one embodiment, the position of the center of mass of the first balance mass is radially opposite to the position of the eccentric shaft.

In one embodiment, the phase adaptation mechanism includes a counter gear and a counter gear set, and the second driving gear portion drives the counter gear to rotate in an opposite direction through the counter gear set.

In one embodiment, the first drive gear portion is a bevel gear and the second drive gear portion and the balance gear are helical gears.

In one embodiment, the phase adaptation mechanism is arranged such that the rotational speed of the combined drive gear is the same as the rotational speed of the balance gear.

In one embodiment, the combination drive gear is axially aligned with the balance gear.

In one embodiment, the first counterbalance mass is disposed on the combination drive gear such that the combination drive gear has a center of mass that is offset from a center of rotation.

In one embodiment, the second balance mass is disposed on the balance gear such that the balance gear has a center of mass that is offset from a center of rotation.

In one embodiment, the diameter of the first drive gear portion is smaller than the diameter of the second drive gear portion.

In one embodiment, the first drive gear portion is located above the second drive gear portion, and the motor drives the first drive gear portion.

According to an embodiment of another aspect of the present invention, there is provided a reciprocating power tool having the above balance mechanism.

The utility model discloses a balance mechanism can integrate with reciprocating type electric tool's actuating mechanism to have compact structure, enable actuating mechanism and occupy less space relatively. In addition, the simple structure can effectively reduce the manufacturing cost. The balance mechanism is also suitable for other reciprocating electric tools.

Drawings

Embodiments of the invention are described below, by way of example, with reference to the accompanying drawings, in which:

figure 1 is a schematic diagram of a reciprocating power tool according to one embodiment of the present invention;

fig. 2 is an exploded view of a drive mechanism according to one embodiment of the present invention, including a counterbalance mechanism.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Fig. 1 shows a reciprocating power tool 1, in particular a reciprocating electric saw, according to an embodiment of the present invention. The reciprocating electric tool 1 includes a machine body 2, a motor 3 disposed in the machine body 2, a tool holding portion 4, and a driving mechanism (not shown) connecting the motor 3 to the tool holding portion 4. The tool holder 4 may be fixedly connected to a cutting tool (not shown) and the motor 3 is drivingly connected to a drive mechanism for providing power for cutting. The driving mechanism is provided with a balance mechanism, and vibration generated by parts reciprocating in the driving mechanism during operation can be effectively reduced. The general construction and operation of the reciprocating power tool described above is well known to those skilled in the art and will not be described further herein.

Fig. 2 depicts a drive mechanism 120 within a power tool body, including a counterbalance mechanism 121, in accordance with one embodiment of the present invention. The drive mechanism 120 may be used with a reciprocating power saw such as that shown in fig. 1, but is not so limited. The drive mechanism 120 includes a housing 122, and the tool holding portion 104 is slidably supported by the housing 122. The driving mechanism 120 further includes a combination driving gear 113 disposed therein, and the housing 122 is configured to support the driving gear 113 for rotation. The combination drive gear 113 includes two parts, a first drive gear part 113a and a second drive gear part 113b located below the first drive gear part, which rotate in synchronization, and the first drive gear part 113a is a bevel gear that is provided to mesh with the bevel pinion gear 105. The pinion 105 is fixedly connected to an output shaft (not shown) of the motor, so that the motor drives the first driving gear portion 113a and thus the combination driving gear 113 to rotate via the pinion 105. The second drive gear portion 113b is a helical gear that is arranged to mesh with an idler gear 131, which will be described in detail below. The first drive gear portion 113a has an overall size (e.g., diameter) smaller than that of the second drive gear portion 113b, and is disposed concentrically up and down to avoid interference of respective gear meshing movements.

The combination drive gear 113 is provided with an eccentric shaft 114 which is movably connected to the tool holding portion 104. The tool holding portion 104 is configured to move linearly relative to the housing 122 and has an elongated opening 106 in driving connection with the eccentric shaft 114 such that rotation of the combination drive gear 113 causes the tool holding portion 104 to move linearly in a reciprocating manner to cause a cutting tool (not shown) secured to the distal end of the tool holding portion 104 to perform a cutting operation. Since the tool holding portion 104 has a certain mass, it generates a reciprocating momentum upon reciprocating. According to other embodiments, the combination driving gear 113 may be driven by the motor through other conventional mechanical driving methods and motor driving connection, which are not described herein.

The balance mechanism 121 includes a first balance mass body 125a and a second balance mass body 125b, which are provided to rotate in opposite directions on the same rotation axis. A first balance mass 125a is provided on the combination drive gear 113, and in particular, the first balance mass 125a is provided below the second drive gear portion 113b at an offset from the center of rotation of the combination drive gear 113, which may be integrally formed with the combination drive gear 113 or may be coupled to the combination drive gear 113 by fastening such that the combination drive gear 113 has a center of mass 123a offset from the center of rotation. The position of the centroid 123a of the combination drive gear 113 is diametrically opposed to the position of the eccentric shaft 124. Alternatively, the first driving gear portion 113a may be disposed below the second driving gear portion 113b, in which case the first balancing mass body 125a is disposed above the second driving gear portion 113 b.

According to fig. 2, the balancing mechanism 121 further comprises a phase adaptation mechanism 126 in driving connection with the second balancing mass 125 b. The phase adaptation mechanism 126 includes a balance gear 129 and a reversing gear set 130. The balance gear 129 and the combined drive gear 113 are coaxially arranged, i.e. the rotation central axes of the two are aligned, but the two are separately arranged up and down and are respectively arranged on the upper and lower sides of the tool clamping part 104, the balance gear 129 is arranged in the upper half shell 122 above the tool clamping part 104, and the combined drive gear 113 is arranged in the lower half shell 122 below the tool clamping part 104; and there is no direct kinematic coupling between the two, the motion of the combination drive gear 113 is transmitted through the reversing gear set 130 to the balance gear 129. A needle bearing 114a is provided between the eccentric shaft 114 and the elongated opening 106 to promote the smoothness of the relative movement of the two when subjected to a load. The end of the eccentric shaft 114 has a threaded section which passes through the needle bearing 114a and is fastened by a washer 115 and a retainer ring 116. Similarly, a balance gear 129 is coupled to the shaft 127 by a key, the upper end of the shaft 127 passes through the balance gear 129 and is mounted in the upper housing half 122 by a needle bearing 127a, and the lower end has a threaded section, fastened to the balance gear 129 by a washer 141 and a retaining ring 142. In this manner, balance gear 129, when driven by reversing gear set 130, is free to rotate with shaft 127 within upper housing half 122. The eccentric shaft 114 drives the linear movement of the tool holder 104 and the combination drive gear 113 drives the counter gear set 130 and in turn the balance gear 129.

Further, the balance gear 129 is provided to have the second balance mass body 125b deviated from the center thereof. Likewise, the second balance mass 125b may be integrally formed with the balance gear 129 or may be coupled to the balance gear 129 by fastening such that the balance gear 129 has a center of mass 129a that is offset from a center of rotation thereof. The combination drive gear 113 is axially aligned with the balance gear 129.

The reversing gear set 130 of the phase adaptation mechanism 126 is in driving connection and meshing engagement with the second drive gear portion 113b of the combination drive gear 113 and the balance gear 129. The reverse gear set 130 is composed of an idler gear 131 and an idler gear 132. Specifically, an idler gear 131 and an intermediate gear 132 are provided in the housing 122 and pivotally supported by the housing 122. The second driving gear portion 113b is engaged with the idle gear 131, the idle gear 131 is engaged with the intermediate gear 132 to rotate, and the intermediate gear 132 is engaged with the balance gear 129. The second drive gear portion 113b drives the balance gear 129 through the reversing gear set 130, causing the balance gear 129 to rotate in a direction opposite to the rotation direction of the second drive gear portion 113 b. Advantageously, the second driving gear portion 113b, the idle gear 131 and the intermediate gear 132 and the balance gear 129 are all of helical gear type. The second drive gear portion 113b and the counter gear set 230 of the phase adaptation mechanism 126 should be provided with respective rotational ratios such that the rotational speed of the balance gear 129 is the same as the rotational speed of the second drive gear portion 113 b. The housing 122 of the driving mechanism 120 is further provided with a gear cover 122a, which covers the balance gear 129 and the reversing gear set 230 to prevent foreign objects from entering the balance mechanism 121 and affecting its operation.

As shown in fig. 2, the balance mechanism 121 is arranged such that when the combination drive gear 113 and the balance gear 129 rotate relative to each other, the respective centroids 123a, 129a of the combination drive gear 113 and the balance gear 129 overlap twice for each complete rotation, successive overlaps producing a reciprocating momentum in the direction of the axis a. Since the combined driving gear 113 and the balance gear 129 rotate relatively, the momentum of each

balance mass body

125a,125b generated perpendicular to the axis a during rotation is cancelled out, so that the balance mechanism 121 only generates the reciprocating momentum in the direction of the axis a. Since the first balance mass body 125a and the second balance mass body 125b are always located opposite to the eccentric shaft 114 of the combination drive gear 113 in the radial direction at each overlapping time, that is, the phase of the reciprocating momentum generated by the balance mechanism 121 is opposite to the phase of the reciprocating momentum generated by the tool holding part 104, the momentum M2 generated by the balance mechanism 121 in each stroke is offset from at least a part of the momentum M1 generated by the tool holding part 104, thereby providing a good balance or vibration damping effect for the reciprocating power tool.

According to the utility model provides a balance mechanism, it can dispose in reciprocating type electric saw or jig saw, can reduce the vibration when operating effectively.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. Accordingly, the above-described embodiments should be regarded as illustrative rather than restrictive.

Although the present description has been described in terms of embodiments, not every embodiment encompasses only a single solution, for example, the

needle bearings

114a, 127a may be replaced by ball bearings, or other suitable bearing types. On the other hand, the second driving gear portion 113b, the idle gear 131, the intermediate gear 132 and the balance gear 129 may be engaged with each other by spur gears having a suitable rotation ratio. This description is given for clarity only, and those skilled in the art should be able to integrate the description as a whole, and the technical solutions in the embodiments may be appropriately combined to form other embodiments that can be understood by those skilled in the art. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A balance mechanism arranged in a reciprocating electric tool, the reciprocating electric tool comprises a motor, a reciprocating tool clamping part and a driving mechanism in driving connection with the motor and the tool clamping part, the driving mechanism comprises a shell and a combined driving gear arranged in the shell, the combined driving gear is movably connected with the tool clamping part through an eccentric shaft arranged on the combined driving gear, the motor drives the tool clamping part to reciprocate through the eccentric shaft,

the combined driving gear is characterized by comprising a first driving gear part and a second driving gear part which are concentrically arranged and synchronously rotate, and the balance mechanism comprises a first balance mass body, a second balance mass body and a phase adaptation mechanism which is in driving connection with the second balance mass body, wherein the first balance mass body and the second balance mass body are rotationally driven by the combined driving gear; the eccentric shaft drives the tool clamping part to reciprocate, the second driving gear part drives the phase adaptation mechanism to enable the second balance mass body to rotate opposite to the first balance mass body, momentum generated by the second balance mass body and perpendicular to the reciprocating direction of the tool clamping part is mutually counteracted, reciprocating balance momentum generated by the balance mechanism and parallel to the reciprocating direction of the tool clamping part is counteracted with at least a part of reciprocating momentum generated by the reciprocating motion of the tool clamping part, and therefore at least a part of vibration generated when the tool clamping part reciprocates is reduced.

2. The balance mechanism of claim 1 wherein the phase adaptation mechanism reverses the phase of the reciprocating momentum generated by the balance mechanism to the phase of the reciprocating momentum generated by the tool gripping portion.

3. The balance mechanism of claim 1, wherein the position of the center of mass of the first balance mass is disposed diametrically opposite the position of the eccentric shaft.

4. The balance mechanism of claim 1 wherein the phase adaptation mechanism includes a balance gear and a reversing gear set, the second drive gear portion driving the balance gear to rotate in an opposite direction through the reversing gear set.

5. The balance mechanism of claim 4 wherein said first drive gear portion is a bevel gear and said second drive gear portion and said balance gear are helical gears.

6. A balance mechanism according to claim 4, wherein the phase adaptation mechanism is arranged such that the speed of rotation of the combination drive gear is the same as the speed of rotation of the balance gear.

7. The balance mechanism of claim 4 wherein the combination drive gear is axially aligned with the balance gear.

8. The counterbalance mechanism of claim 4, wherein the first counterbalance mass is disposed on the combination drive gear such that the combination drive gear has a center of mass that is offset from a center of rotation.

9. The counterbalance mechanism of claim 8, wherein the second counterbalance mass is disposed on the counterbalance gear such that the counterbalance gear has a center of mass that is offset from a center of rotation.

10. The counterbalance mechanism of claim 1, wherein the first drive gear portion has a diameter smaller than a diameter of the second drive gear portion.

11. The counterbalance mechanism of claim 1, wherein the first drive gear portion is located above the second drive gear portion, the motor driving the first drive gear portion.

12. A reciprocating power tool, characterized in that it comprises a balancing mechanism according to any one of claims 1-11.