CN111408792A

CN111408792A - Handheld cutting machine

Info

Publication number: CN111408792A
Application number: CN202010278314.3A
Authority: CN
Inventors: 马建英; 李成道
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2014-01-10
Filing date: 2014-01-10
Publication date: 2020-07-14
Also published as: CN104772521A

Abstract

The invention discloses a handheld cutting machine which comprises a shell, a motor arranged in the shell, and a saw blade in transmission connection with an output rotating shaft of the motor through a transmission mechanism, wherein the saw blade is positioned on one side of the front end of the shell; the second gear of the cutting machine can be independently increased without influencing other performances, so that the transmission ratio can be effectively improved, and the cutting torque is obviously improved.

Description

Handheld cutting machine

The invention is a divisional application of the Chinese invention patent application with the application number of 201410010679.2, namely a handheld cutter, which is applied by the applicant at 1, 10 and 2014.

Technical Field

The invention relates to a handheld cutting machine capable of improving input-output transmission ratio.

Background

The handheld cutter is the most commonly used cutting tool in the electric tool, and generally, in order to improve the torque of the handheld cutter, a multi-stage transmission device is arranged on an output shaft of a motor to reduce the rotating speed of the motor. In the prior art, a two-stage transmission mode is often adopted, a first stage uses spiral bevel gear transmission to change the rotation of a motor by 90 degrees, a second stage uses straight-tooth cylindrical gear transmission, the transmission can sequentially involve four gears a, b, c and d, the four gears are meshed by means of an intermediate shaft and an output shaft, the teeth number of the four gears is Za, Zb, Zc and Zd, and the total transmission ratio n is (Zb Zd)/(Za Zc).

If the output torque of the tool needs to be increased, the output rotating speed of the tool needs to be reduced, so that a larger transmission ratio is needed, namely n is needed to be larger and better; if n is increased, Zb and Zd are as large as possible, Za and Zc are as small as possible, but Za is used as a spiral bevel gear, the number of teeth of the spiral bevel gear has a lower limit, namely the down-regulation space of the spiral bevel gear is limited; zb is limited by the shell and the output shaft, and the upper adjusting space is limited; zc and Zd respectively correspond to the size of the gear c and the gear d, in fact, the gear c and the gear d determine the center distance between the intermediate shaft and the output shaft, if Zc and Zd are both small, n can be increased, but the center distance is also reduced, and the result caused by the reduction of the center distance is that Zb cannot be increased, so that the final value of n is influenced; on the other hand, to ensure the cutting depth of the saw blade, the value of Zd cannot be too large, which also results in n not being too large. In summary, the transmission mechanism in the prior art cannot balance the relationship among the transmission ratio, the center distance and the cutting depth, and there is no optimal solution.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a handheld cutting machine, which comprises a shell, a motor arranged in the shell, and a saw blade in transmission connection with an output rotating shaft of the motor through a transmission mechanism, wherein the saw blade is positioned on one side of the front end of the shell, and the handheld cutting machine is characterized in that: the transmission mechanism at least comprises a middle shaft and an output shaft which are rotatably arranged on the shell, a first gear arranged on an output rotating shaft of the motor, a second gear and a third gear which are arranged at two ends of the middle shaft, and a fourth gear arranged at one end of the output shaft far away from the saw blade, wherein the rotating axial lines of the middle shaft and the output shaft are parallel to each other, the other end of the output shaft is connected with the saw blade, the first gear is meshed with the second gear, the third gear is meshed with the fourth gear, and the output shaft is positioned between the saw blade and the second gear.

Preferably, the output shaft is sleeved with a first bearing and a second bearing, and the first bearing and the second bearing are located between the fourth gear and the saw blade.

Preferably, the first gear is a tapered pinion gear, and the second gear is a tapered bull gear.

The handheld cutting machine ingeniously gives a certain space for the second gear in the design of the transmission mechanism, so that the second gear can increase the diameter and the tooth number, meanwhile, no influence is caused on other gears, and the transmission ratio is effectively improved under the condition of not influencing the cutting depth and the center distance.

Drawings

FIG. 1 is a front view of the hand held cutting machine of the present invention;

FIG. 2 is a first cross-sectional view of the drive portion of the hand held cutting machine of the present invention;

FIG. 3 is a second cross-sectional view of the drive portion of the hand held cutting machine of the present invention;

FIG. 4 is a first cross-sectional view of the drive portion of a prior art hand held cutting machine;

fig. 5 is a second cross-sectional view of the drive portion of a prior art hand held cutting machine.

In the drawings:

1-shell, 2-motor, 3-transmission mechanism, 4-saw blade;

31-first gear, 32-second gear, 33-third gear, 34-fourth gear, 35-intermediate shaft, 36-output shaft, 37-first bearing, 38-second bearing;

41-shield.

Detailed Description

Preferred embodiments of the hand-held cutting machine of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1-3 illustrate the structure of the hand-held cutting machine of the present invention, while fig. 4-5 illustrate the structure of a prior art hand-held cutting machine for comparison. The handheld cutting machine comprises a shell 1, a motor 2 arranged in the shell 1, a transmission mechanism 3 in transmission connection with a rotating shaft of the motor 2, and a saw blade 4 connected with the transmission mechanism 3, wherein the axial lead of the rotating shaft of the motor 2 is vertical to the projection of the axial lead of the rotating shaft of the saw blade 4 on the horizontal plane, and a protective shield 41 is arranged outside the saw blade 4 for protection. The transmission mechanism 3 includes a first gear 31, a second gear 32, a third gear 33, and a fourth gear 34, the first gear 31 is a bevel pinion, the bevel pinion is engaged with the second gear 32, the second gear 32 is coaxially connected to the third gear 33 through an intermediate shaft 35, the third gear 33 is engaged with the fourth gear 34, the fourth gear 34 is fixedly connected to one end of an output shaft 36, the output shaft 36 is fixed to a second bearing 38 through a first bearing 37, wherein the first bearing 37 and the second bearing 38 are located on the same side of the fourth gear 34, that is, between the fourth gear 34 and the saw blade 4. Compared with the prior art, the second gear 32 has no obstacle below, so the diameter and the number of teeth of the second gear can be made as large as possible, and there is no influence on the size of the fourth gear 34.

If the total gear ratio of the entire transmission mechanism 3 is n, the number of teeth of the first gear 31 is Za, the number of teeth of the second gear 32 is Zb, the number of teeth of the third gear 33 is Zc, and the number of teeth of the fourth gear 34 is Zd, the total gear ratio n is (Zb × Zd)/(Za × Zc). In the prior art, Zb is limited in value due to the structure, but in the technical scheme, Zb can be made as large as possible, and Za, Zc and Zd can be kept unchanged regardless of the size of Zb, so that variables are effectively controlled, and parameters of the second gear 32 can be adjusted differently according to requirements.

After a plurality of tests, after the number of teeth and the diameter of the second gear 32 are properly increased, the total transmission ratio can be remarkably improved on the premise of not influencing other performances of the tool, and generally can be improved by 8.5-9.7.

Compared with the prior art, the handheld cutting machine provided by the invention has the advantages that the holding space of the handheld cutting machine is obviously increased on the premise of not influencing the performance, and more comfortable holding feeling is brought to a user.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and implement the invention, and not to limit the scope of the invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.

Claims

1. The utility model provides a handheld cutting machine, includes casing (1), locates motor (2) in casing (1), with drive mechanism (3) that the output pivot transmission of motor (2) is connected, saw bit (4) of being connected with drive mechanism (3), saw bit (4) are located one side of casing (1) front end, its characterized in that: the transmission mechanism at least comprises an intermediate shaft (35) and an output shaft (36) which are rotatably arranged on the shell, a first gear (31) which is arranged on an output rotating shaft of the motor (2), a second gear (32) and a third gear (33) which are arranged on the intermediate shaft (35), and a fourth gear (34) which is arranged at one end of the output shaft (36) far away from the saw blade (4), wherein the rotating axes of the intermediate shaft (35) and the output shaft (36) are parallel to each other, the other end of the output shaft (36) is connected with the saw blade (4), the first gear (31) is meshed with the second gear (32), the third gear (33) is meshed with the fourth gear (34), the output shaft (36) is arranged between the saw blade (4) and the second gear (32), and the output shaft (36) is only formed by a first bearing (37), The second bearing (38) is supported, the first bearing (37) and the second bearing (38) are both positioned between the fourth gear (36) and the saw blade (4), the direction of the middle shaft close to the saw blade is defined as the upper direction, and the third gear is directly arranged above the second gear.

2. The hand-held cutting machine according to claim 1, wherein: the first gear (31) is a conical small gear, and the second gear (32) is a conical large gear.

3. The hand-held cutting machine according to claim 1, wherein: and an output rotating shaft of the motor (2) is vertical to the output shaft (36).

4. The utility model provides a handheld cutting machine, includes casing (1), locates motor (2) in casing (1), with drive mechanism (3) that the output pivot transmission of motor (2) is connected, saw bit (4) of being connected with drive mechanism (3), saw bit (4) are located one side of casing (1) front end, its characterized in that: the transmission mechanism at least comprises an intermediate shaft (35) and an output shaft (36) which are rotatably arranged on the shell, a first gear (31) which is arranged on an output rotating shaft of the motor (2), a second gear (32) and a third gear (33) which are arranged on the intermediate shaft (35), and a fourth gear (34) which is arranged at one end of the output shaft (36) far away from the saw blade (4), wherein the rotating axes of the intermediate shaft (35) and the output shaft (36) are parallel to each other, the other end of the output shaft (36) is connected with the saw blade (4), the first gear (31) is meshed with the second gear (32), the third gear (33) is meshed with the fourth gear (34), the output shaft (36) is arranged between the saw blade (4) and the second gear (32), and the output shaft (36) is only formed by a first bearing (37), A second bearing (38) is supported, and the first bearing (37) and the second bearing (38) are both located between the fourth gear (36) and the saw blade (4).

5. The hand-held cutting machine according to claim 4, wherein: the first gear (31) is a conical small gear, and the second gear (32) is a conical large gear.