CN219655219U

CN219655219U - Gear box and electric tool

Info

Publication number: CN219655219U
Application number: CN202321390956.8U
Authority: CN
Inventors: 陈杰
Original assignee: Suzhou Duobei Tool Technology Co ltd
Current assignee: Suzhou Duobei Tool Technology Co ltd
Priority date: 2023-06-02
Filing date: 2023-06-02
Publication date: 2023-09-08
Anticipated expiration: 2033-06-02

Abstract

The utility model discloses a gear box and an electric tool, and belongs to the technical field of electric tools. The gearbox comprises a box body and three-stage planetary gear trains which are arranged in the box and transmit power, wherein each stage of planetary gear train comprises a sun gear which is used as an input part of the planetary gear train, a plurality of planetary gears which encircle and mesh with the sun gear, an inner gear ring and a planetary carrier which carries the plurality of planetary gears and is used as an output part of the planetary gear train, and in the one-stage planetary gear train and/or the three-stage planetary gear train, the sun gear and the planetary gears are helical gears; in the secondary planetary gear train, the ring gear is configured to be movable in the axial direction of the case to engage the planetary gear in the secondary planetary gear train or to engage the carrier in the primary planetary gear train to achieve high-low gear switching. The gear box and the electric tool disclosed by the utility model have the advantages of low noise, low vibration and the like.

Description

Gear box and electric tool

Technical Field

The present utility model relates to the field of power tools, and more particularly, to a gear case and a power tool having the same.

Background

At present, the electric drill tools are required to be small and exquisite, convenient to operate, stable in running and low in noise. In electric drill type tools, however, the gearbox is an important component. The gear box generally uses a multistage planetary gear train as a speed reducing mechanism for transmitting rotation speed and torque, wherein each stage of planetary gear train also mostly uses straight spur gears as basic components for transmission. The straight tooth gear has simple structure and easy processing and production, but the noise and vibration of the gear structure can be larger, and the strength of the straight tooth gear is small under the condition of the same structure size.

The information disclosed in this background section is only for enhancement of understanding of the general background of the utility model and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

Disclosure of Invention

The object of the present utility model is to provide a gearbox which is at least capable of reducing noise and vibrations.

The utility model aims to provide an electric tool which comprises the gear box and has the advantages of low noise, low vibration and the like.

To achieve the above object, an embodiment of the present utility model provides a gear box including a box body, and a primary planetary gear train, a secondary planetary gear train and a tertiary planetary gear train which are sequentially provided in the box body in an axial direction of the box body and transmit power, each of the primary planetary gear trains including a sun gear as an input member of the planetary gear train, a plurality of planetary gears surrounding and meshing with the sun gear, an inner gear ring, a carrier carrying the plurality of planetary gears and serving as an output member of the planetary gear train,

in the primary planetary gear train and/or the tertiary planetary gear train, the inner gear ring surrounds and is meshed with a plurality of planetary gears, and the sun gear and the planetary gears are helical gears;

in the second-stage planetary gear train, the annular gear is configured to be switchable between a first position in which the annular gear is fixed relative to the case and surrounds and engages the planetary gears in the second-stage planetary gear train and a second position in which the annular gear surrounds and engages the planet carrier in the first-stage planetary gear train.

In one or more embodiments of the present utility model, the helical gear has a helix angle of 5 to 25 degrees

In one or more embodiments of the present utility model, the helix angle is 10 to 20 °

In one or more embodiments of the present utility model, the gearbox further comprises a shift switch operable to switch the ring gear in the secondary planetary gear train between a first position and a second position, the shift switch being connected to the ring gear.

In one or more embodiments of the present utility model, the gear case further includes a locking member provided in the case, and the ring gear is fixed with respect to the case by the locking member when in the first position in the secondary planetary gear train.

In one or more embodiments of the utility model, the gearbox further comprises an output shaft, which is connected to a planet carrier in the three-stage planetary gear train.

In one or more embodiments of the utility model, the output shaft is connected to the planet carrier by a shaft lock assembly comprising:

the shaft lock ring is fixed in the box body;

the cam block is fixed on the output shaft and positioned in the shaft lock ring;

and the shaft lock pins are positioned between the shaft lock rings and the cam blocks.

In one or more embodiments of the present utility model, the gearbox further includes a torsion adjusting assembly, the torsion adjusting assembly includes a torsion cup, an elastic member, a resisting member, and an abutting assembly, the torsion cup is sleeved outside the box and can move along an axial direction of the box, the elastic member, the resisting member, and the abutting assembly are all located inside the torsion cup and are sequentially arranged along the axial direction, the abutting assembly is arranged between the resisting member and an inner gear ring in the three-stage planetary gear train, one end of the elastic member abuts against the torsion cup, and the opposite end abuts against the resisting member.

In one or more embodiments of the present utility model, the abutment assembly includes a roller and a steel ball, the roller being disposed between the roller and an inner gear ring in a three-stage planetary gear train.

An embodiment of the present utility model provides a power tool including the above-described gear box.

Compared with the prior art, the planetary gear train adopts the bevel gears, so that the problems of high noise, high vibration and the like of the gear box can be effectively solved, namely, the planetary gear train adopts the bevel gear design, and the noise and the vibration of the gear box can be reduced. On the other hand, by adopting the helical gear, the structural strength of the gear can be improved, and the service life of the gear box is further prolonged _， And the helical gear is adopted, so that the helical gear can be smaller than the straight gear in structure under the same strength requirement, and the miniaturization design of the gear box is facilitated.

Drawings

FIG. 1 is a perspective view of a power tool according to one embodiment of the present utility model;

FIG. 2 is a cross-sectional view of a gearbox according to an embodiment of the present utility model;

FIG. 3 is an exploded view of a gearbox according to an embodiment of the present utility model;

FIG. 4 is a perspective view of a primary planetary gear train according to an embodiment of the utility model;

fig. 5 is a perspective view of a three-stage planetary gear train according to an embodiment of the present utility model.

Detailed Description

The following detailed description of embodiments of the utility model is, therefore, to be taken in conjunction with the accompanying drawings, and it is to be understood that the scope of the utility model is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.

The gearbox disclosed by the utility model can avoid the problems, and has the advantages of low noise, low vibration and compact structure.

Referring to fig. 1 to 3, a gear box according to the present utility model is applicable to an electric tool M shown in fig. 1, and includes a box 10, and a primary planetary gear train 20, a secondary planetary gear train 30, and a tertiary planetary gear train 40 provided in the box 10. The primary planetary gear train 20, the secondary planetary gear train 30 and the tertiary planetary gear train 40 are sequentially arranged in the box 10 along the axial direction of the box 10, the primary planetary gear train 20 is connected with a power mechanism (not shown), and the tertiary planetary gear train 40 is connected with an output shaft 50. In operation, the power mechanism inputs power into the primary planetary gear train 20, the primary planetary gear train 20 transmits power through the secondary planetary gear train 30 to the tertiary planetary gear train 40, and the tertiary planetary gear train 40 outputs power outwardly through the output shaft 50. That is, at the time of power transmission, power generated by the power mechanism is transmitted to the output shaft 50 through the primary planetary gear train 20, the secondary planetary gear train 30, and the tertiary planetary gear train 40 in this order. The power mechanism is preferably an electric motor, and of course, a mechanism capable of inputting power may be selected according to actual requirements.

As shown in fig. 2 and 3, the case 10 includes a first case 10a, a second case 10b, and a case cover 10c. The first casing 10a and the second casing 10b are fastened in butt joint in the axial direction by screws, and the case cover 10c covers the end of the second casing 10b, and the three form the case 10. Wherein, the first shell 10a is provided with a shaft hole, and the output shaft 50 can be assembled in the box 10 through a bearing and extend outwards out of the box 10 through the shaft hole; the second housing 10b is provided with a through hole for connecting a power output member of the power mechanism, such as a rotating shaft of a motor, to the primary planetary gear train 20.

As shown in fig. 2 to 5, the primary planetary gear train 20, the secondary planetary gear train 30 and the tertiary planetary gear train 40 each include a sun gear a, a plurality of planet gears b, a planet carrier c and an inner gear ring d. Wherein, the sun gear a is used as a power input part of the planetary gear train to input power to the planetary gear train; a plurality of planet gears b are arranged around the sun gear a and meshed with the sun gear a; the carrier c is used to carry a plurality of planetary gears b, and also serves as a power output member of the planetary gear train to output power to the outside. The inner gear ring d surrounds the outer circumferences of the plurality of planetary gears b and is meshed with the planetary gears b, and the inner gear ring d can be arranged to be movable according to actual requirements, for example, in the embodiment, in the primary planetary gear train 20, a protrusion is arranged on the outer circumference of the inner gear ring d, and the protrusion can be matched with a groove in the box 10 so as to fix the inner gear ring d in the box 10; in the secondary planetary gear train 30, the ring gear d is movable in the axial direction of the case 10 to achieve a high-low gear shift.

Further, in the three-stage planetary gear train 40, the power output member of the planetary gear train located upstream is connected to the power input member of the planetary gear train located downstream to achieve power transmission, such as the carrier c of the primary planetary gear train 20 located upstream is connected to the sun gear a of the secondary planetary gear train 30 located downstream to achieve power transmission.

As shown in fig. 4 to 5, in the primary planetary gear train 20 and/or the tertiary planetary gear train 40, the teeth of the sun gear a, the planet gear b and the ring gear d are all helical teeth, that is, the sun gear a and the planet gear b are all helical gears. Through adopting the helical gear, can effectively solve the big, the big scheduling problem of vibration of gear box noise, promptly the planetary gear train adopts the helical gear design, can reduce the noise, the vibration of gear box. Meanwhile, by adopting the helical gear, the structural strength of the gear can be improved, the service life of the gear box is further prolonged, and meanwhile, the miniature design of the gear box can be facilitated. The bevel gear is adopted to solve the problems of large noise, large vibration and the like of the gear box, the service life of the gear box is prolonged, and the gear box is beneficial to miniaturization design of the gear box, because the bevel gear has higher contact ratio than a straight gear under the same condition and the tooth surface of the bevel gear gradually enters into engagement in the engagement process, the impact on the tooth of the bevel gear in one engagement period is smaller, and therefore the operation of the bevel gear is more stable and the noise is smaller. Under the same condition, the helical gear can obtain higher strength than the straight gear under the same external dimension, so that the service life of the gear box is prolonged. Meanwhile, under the same strength requirement, the bevel gear can be smaller than the straight gear in structure, and the miniaturization design of the gear box is facilitated.

Further, in the sun gear a and the planet gear b using the bevel gear, the helix angle of the bevel gear is preferably 5 to 25 °. In practice, the helix angle is preferably set to 10 to 20 °. By setting the helix angle to be within the above range, noise and vibration of the gear box can be effectively reduced.

In the secondary planetary gear train 30, as shown in fig. 2 to 3, in order to enable the gear box to realize a high-low speed shift, the ring gear d is movable in the axial direction of the case 10 within the case 10, and has a first position and a second position. When the ring gear d is in the first position, the ring gear d remains stationary with respect to the housing 10 and the ring gear d encircles and engages the planet b in the planetary gear set in which it is located (i.e. the secondary planetary gear set 30). When ring gear d is in the second position, ring gear d encircles and engages carrier c in primary planetary gear train 20. In particular, the outer periphery of the carrier c in the primary planetary gear train 20 is provided with teeth that cooperate with the ring gear d so that the ring gear d meshes therewith in the second position. By switching the ring gear d in the secondary planetary gear train 30 between the first position and the second position, a change in the gear ratio is finally achieved, and a high-low gear change of the gearbox is achieved.

Further, in order to keep the ring gear d fixed at the first position, a locking member 60 is further provided in the case 10, and the locking member 60 locks the ring gear d to be fixed against rotation with respect to the case 10 when the ring gear d moves to the first position. The locking piece 60 is kept fixed with the box body 10, and the locking piece 60 can be fixed in the box body 10 through the cooperation of the protrusion and the groove. In this embodiment, the locking member 60 is a locking ring, the inner circular surface of the locking ring is provided with at least one protrusion, the outer circumference of the ring gear d is provided with at least one matched groove, and the ring gear d is kept fixed relative to the case 10 in the first position by matching the protrusion and the groove. Of course, in other embodiments, a groove may be provided in the locking ring, and the ring gear d may be provided with a protrusion to lock the ring gear d, which may be set according to actual requirements.

Further, in order to switch the ring gear d in the secondary planetary gear train 30 between the first position and the second position, the gearbox further includes a shift switch 70. The shift switch member 70 is connected to the ring gear d to control the ring gear d to move to the first position or the second position. In this embodiment, the shift switching member 70 is a bending member made of a metal wire, as shown in fig. 3, and the bending member can be further operated by a key set on the housing of the electric tool to realize gear switching.

As shown in connection with fig. 2 to 3, the gear box further includes a shaft lock assembly 80 provided in the box body 10, and the power output part in the three-stage planetary gear train 40 is connected with the output shaft 50 through the shaft lock assembly 80, that is, the planet carrier c in the three-stage planetary gear train 40 is connected with the output shaft 50 through the shaft lock assembly 80 to transmit power to the output shaft 50. Specifically, the shaft lock assembly 80 includes a shaft lock collar 81, a plurality of shaft lock pins 82, and a cam block 83. Wherein the shaft lock 81 is fixed in the case 10. In practice, the outer periphery of the shaft lock ring 81 is provided with a protrusion, the box 10 is provided with a matched groove, and the shaft lock ring 81 is fixed in the box 10 under the matching of the protrusion and the groove. The cam block 83 is sleeved on the rotating shaft and is positioned in the shaft locking ring 81, and the cam block 83 can be matched with the planet carrier c in the three-stage planetary gear train 40 to realize power transmission. Shaft lock pins 82 are rollers 94, and a plurality of shaft lock pins 82 are located between shaft lock collar 81 and cam block 83.

When the carrier c of the three-stage planetary gear train 40 transmits torque to the output shaft 50, a driving surface (not shown) of the carrier c contacts a self-locking plane (not shown) on the cam block 83, and the carrier c can drive the shaft lock pin 82 to rotate synchronously with the output shaft 50. Since the self-locking plane on the cam block 83 and the inner circular surface of the shaft lock ring 81 do not form an included angle, self-locking cannot be realized, and torque output can be completed. When torque is transmitted to the inside of the gear box through the output shaft 50, an included angle is formed between the self-locking plane on the cam block 83 and the inner circular surface of the shaft lock ring 81, the shaft lock pin 82 and the self-locking plane on the cam block 83 generate relative motion, and the self-locking plane, the inner circular surface of the shaft lock ring 81 and the shaft lock pin 82 are automatically embedded into the included angle, so that the self-locking plane, the inner circular surface of the shaft lock ring 81 and the shaft lock pin 82 are in a relatively static state to form self-locking, and the output shaft 50 cannot transmit torque to the inside of the gear box.

As shown in connection with fig. 2-3, the gearbox further includes a torsion adjustment assembly 90, the torsion adjustment assembly 90 including a torsion cup 91, a resilient member 92, a retaining member 93, and an abutment assembly. The torsion cup 91 is sleeved outside the box 10 and is in threaded connection with the box 10, and under the action of the threads, the torsion cup 91 can move along the axial direction of the box 10. The elastic member 92, the resisting member 93, and the abutting component are all located inside the torsion cup 91, and the elastic member 92, the resisting member 93, and the abutting component are sequentially disposed along the axial direction, that is, the abutting component is disposed between the ring gear d and the resisting member 93 in the three-stage planetary gear train 40. One end of the elastic member 92 abuts against the torsion cup 91, and the opposite end abuts against the stopper 93. The abutment assembly here comprises a roller 94, a steel ball 95. The roller 94 is arranged between the roller 94 and the ring gear d in the three-stage planetary gear train 40, and the resisting member 93 is arranged between the roller 94 and the elastic member 92.

In particular, when the torsion cup 91 is rotated, the torsion cup 91 moves along the axial direction of the case 10 toward the third planetary gear train 40, and compresses the elastic member 92 during the movement, the elastic member 92 further applies a force to the resisting member 93, the resisting member 93 presses the steel balls 95 through the rollers 94, and the steel balls 95 act on the ring gear d in the third planetary gear train 40, so that the ring gear d cannot easily rotate. When the working load increases, the torsion cup 91 can be further rotated to increase the pressure generated by the elastic member 92, so that the acting force of the steel balls 95 on the ring gear d is increased, and the ring gear d is prevented from rotating.

In this embodiment, the torsion cup 91 is screwed to the case 10 by an adjusting nut 96, and the elastic member 92 is preferably a spring, one end of which abuts against the adjusting nut 96 and the opposite end abuts against the stopper 93.

As shown in FIG. 1, the utility model also discloses an electric tool, which comprises the gear box and has the advantages of low noise, low vibration and the like.

The foregoing descriptions of specific exemplary embodiments of the present utility model are presented for purposes of illustration and description. It is not intended to limit the utility model to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the utility model and its practical application to thereby enable one skilled in the art to make and utilize the utility model in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the utility model be defined by the claims and their equivalents.

Claims

1. The gearbox is characterized by comprising a box body, a first-stage planetary gear train, a second-stage planetary gear train and a third-stage planetary gear train, wherein the first-stage planetary gear train, the second-stage planetary gear train and the third-stage planetary gear train are sequentially arranged in the box body along the axial direction of the box body and transmit power, each planetary gear train comprises a sun gear serving as an input part of the planetary gear train, a plurality of planetary gears, an inner gear ring and a planetary carrier, wherein the planetary gears encircle and are meshed with the sun gear, the planetary carriers bear the plurality of planetary gears and serve as output parts of the planetary gear trains,

2. A gearbox according to claim 1 in which the helical angle of the helical gear is in the range 5 to 25 °.

3. A gearbox according to claim 2, wherein the helix angle is 10-20 °.

4. The gearbox of claim 1, further comprising a shift switch operable to switch the ring gear in the secondary planetary gear set between the first position and the second position, the shift switch being connected to the ring gear.

5. The gearbox as recited in claim 1, further comprising a locking member disposed within the housing, wherein the ring gear is secured relative to the housing in the second planetary gear train in the first position by the locking member.

6. The gearbox as recited in claim 1, further comprising an output shaft coupled to a planet carrier in the three stage planetary gear train.

7. The gearbox as recited in claim 6, wherein said output shaft is connected to a planet carrier by a shaft lock assembly, said shaft lock assembly comprising:

the shaft lock ring is fixed in the box body;

8. The gearbox of claim 1, further comprising a torque force adjustment assembly, wherein the torque force adjustment assembly comprises a torque force cup, an elastic member, a resisting member and an abutting assembly, wherein the torque force cup is sleeved outside the gearbox and can move along the axial direction of the gearbox, the elastic member, the resisting member and the abutting assembly are all positioned inside the torque force cup and are sequentially arranged along the axial direction, the abutting assembly is arranged between the resisting member and an inner gear ring in the three-stage planetary gear train, one end of the elastic member abuts against the torque force cup, and the opposite end of the elastic member abuts against the resisting member.

9. The gearbox as recited in claim 8, wherein said abutment assembly comprises rollers and steel balls, said rollers being disposed between said rollers and an annulus gear in a three stage planetary gear train.

10. A power tool comprising a gearbox according to any one of claims 1 to 9.