Motor transmission structure and electric tool

Abstract

The utility model discloses a motor transmission structure and an electric tool. The motor transmission structure comprises a planetary gear device used for being connected with a motor driving shaft, and the planetary gear device comprises a first sun gear arranged on the motor driving shaft in a sleeving mode, a first-stage planetary gear set meshed with the first sun gear and a first planet carrier for fixing a rotating shaft of the first-stage planetary gear set. The first planet carrier is provided with a first positioning hole, a positioning pin fixed relative to a motor driving shaft is inserted in the first positioning hole, and the positioning pin is in clearance fit with the hole wall of the first positioning hole. According to the motor transmission structure, the positioning pin is fixedly connected with the motor driving shaft, and the positioning pin is in clearance fit with the hole wall of the first positioning hole, so that structural vibration caused by no radial positioning of the first-stage planet carrier is reduced, and abrasion between gears is also reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of power tools, and particularly relates to a motor transmission structure and a power tool. Background Art

[0002] The electric drill is one of the commonly used power tools and is mainly used for drilling work. The electric drill usually includes a motor, a speed regulating mechanism, and a drill bit clamping mechanism. The speed regulating mechanism usually uses a planetary gear set to adjust the output speed of the electric drill. During operation, the output shaft of the motor drives the speed regulating mechanism to rotate, and the speed regulating mechanism drives the drill bit clamping mechanism to rotate, thereby driving the drill bit located in the drill bit clamping tool to rotate to complete the drilling work.

[0003] In the prior art, the planetary gear set usually includes a multi-stage planet carrier installed in a housing, and the multi-stage planet carrier is basically in a free state, that is, the multi-stage planet carrier is mainly indirectly positioned by the circumferential rotation between gears and has no actual reliable fixation. Due to the lateral clearance and axial lateral clearance between gears, this will cause a large floating amount of the gears during the high-speed operation of the whole machine, resulting in a vibration feeling of the whole machine. Especially in the high-speed gear, the vibration of the electric drill will be more obvious when it operates at different angles (horizontal / vertical / inclined, etc.). The reason is that there is a large gap between different stages of planet carriers, and the floating of the first-stage planet carrier will cause the inner gear ring of the second stage to vibrate together, resulting in poor user experience.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a motor transmission structure and a power tool. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a motor transmission structure and a power tool, which can solve the problem of large vibration of the electric drill when the user uses it under different working conditions.

[0006] In order to achieve the above purpose, the technical solution provided by a specific embodiment of the utility model is as follows:

[0007] A motor transmission structure includes a planetary gear device for connecting with a motor drive shaft. The planetary gear device includes a first sun gear sleeved on the motor drive shaft, a first-stage planetary gear set meshing with the first sun gear, and a first planet carrier fixing the rotating shaft of the first-stage planetary gear set. The first planet carrier is provided with a first positioning hole, and a positioning pin relatively fixed to the motor drive shaft is inserted into the first positioning hole. The positioning pin is in clearance fit with the hole wall of the first positioning hole.

[0008] In one or more embodiments of the utility model, the first positioning hole is set as a round hole, and the difference range between the diameter of the round hole and the diameter of the circle where the cross-section of the positioning pin is located is 0.1 - 0.15 mm.

[0009] In one or more embodiments of the present utility model, the ratio of the length of the positioning pin extending into the first positioning hole to the depth of the first positioning hole is not less than 80%.

[0010] In one or more embodiments of the present utility model, a second sun gear is further provided on one side of the first planet carrier away from the first-stage planetary gear set. The planetary gear device further includes a second-stage planetary gear set meshing with the second sun gear, and a second planet carrier fixed to the rotating shaft of the second-stage planetary gear set.

[0011] Wherein, a second positioning hole is formed on the second planet carrier, and the positioning pin is also inserted into the second positioning hole and is in clearance fit with the hole wall of the second positioning hole.

[0012] In one or more embodiments of the present utility model, a first shaft hole for sleeving the motor drive shaft is formed on the first sun gear, and the first positioning hole, the second positioning hole and the first shaft hole are coaxially arranged.

[0013] In one or more embodiments of the present utility model, an oil groove penetrating in the depth direction of the first positioning hole is formed on the hole wall of the first positioning hole.

[0014] In one or more embodiments of the present utility model, a plurality of the oil grooves are uniformly distributed on the hole wall of the first positioning hole.

[0015] In one or more embodiments of the present utility model, the motor transmission structure further includes a housing. The planetary gear device is installed in the housing. The housing is provided with a second shaft hole for the motor drive shaft to pass through, and a bearing for limiting and fixing the motor drive shaft is arranged in the second shaft hole.

[0016] In one or more embodiments of the present utility model, an electric tool is further provided, which includes a motor and the above-mentioned motor transmission structure that is in transmission connection with the motor.

[0017] In one or more embodiments of the present utility model, the positioning pin is integrally formed with the drive shaft of the motor.

[0018] Compared with the prior art, when the motor transmission structure of the present utility model is running, the motor drive shaft drives the first sun gear to rotate, the first sun gear drives the first-stage planetary gear set to rotate, and then drives the first planet carrier to rotate. The positioning pin is fixedly connected with the motor drive shaft, and the positioning pin is in clearance fit with the hole wall of the first positioning hole, so that the transmission between the first sun gear, the first-stage planetary gear set and the first planet carrier is more stable. Therefore, the motor transmission structure of the present utility model not only reduces the structural vibration of the first-stage planet carrier caused by the lack of radial positioning, but also reduces the wear between the gears. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0020] Figure 1 It is a cross-sectional structure diagram of an electric tool in an embodiment of the present invention;

[0021] Figure 2 For Figure 1 The enlarged schematic diagram at position A in

[0022] Figure 3 It is an exploded schematic diagram of some structures in the motor drive structure in an embodiment of the present invention;

[0023] Figure 4 It is an assembly schematic diagram of the planet carrier and the motor drive shaft in an embodiment of the present invention.

[0024] Main reference numeral description:

[0025] 1. Motor drive shaft; 2. First sun gear; 21. First shaft hole; 3. First-stage planetary gear set; 31. First planetary gear; 32. First internal gear ring; 4. First planet carrier; 41. First positioning hole; 42. Oil groove; 43. Second sun gear; 5. Positioning pin; 6. Second-stage planetary gear set; 61. Second planetary gear; 62. Second internal gear ring; 7. Second planet carrier; 71. Second positioning hole; 81. Second shaft hole; 9. Bearing. Detailed implementation manners

[0026] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Embodiment 1

[0028] Referring to Figure 1 , the motor drive structure of this embodiment includes a planetary gear device for connecting with the motor drive shaft 1 and a housing for installing and fixing the planetary gear device.

[0029] Referring to Figure 2 AndFigure 3 The planetary gear device includes a first sun gear 2 sleeved on the motor drive shaft 1, a first-stage planetary gear set 3 meshing with the first sun gear 2, and a first planet carrier 4 fixing the rotating shaft of the first-stage planetary gear set 3. In this embodiment, the first-stage planetary gear set 3 includes a plurality of first planetary gears 31 meshing with the first sun gear 2, and a first inner gear ring 32 meshing with the plurality of first planetary gears 31. The first planet carrier 4 is fixedly connected to the rotating shafts of the plurality of first planetary gears 31. When the motor drive shaft 1 drives the first sun gear 2 to rotate, it can drive the plurality of first planetary gears 31 to rotate around the axis of the first sun gear 2, and further drive the first planet carrier 4 to rotate through the plurality of first planetary gears 31.

[0030] Reference Figure 2 and Figure 3 The first planet carrier 4 is provided with a first positioning hole 41, in which a positioning pin 5 fixed relatively to the motor drive shaft 1 is inserted, and the positioning pin 5 is in clearance with the hole wall of the first positioning hole 41. Therefore, when the first planet carrier 4 rotates, since the positioning pin 5 can provide radial positioning for the first planet carrier 4, the first planet carrier 4 can be abutted and limited by the positioning pin 5, thereby reducing the vibration that may be generated by the first planet carrier 4, and further reducing the vibration of other components on the motor transmission structure.

[0031] Reference Figure 4 The first positioning hole 41 is set as a circular hole, and the difference between the diameter of the circular hole and the diameter of the circle where the cross section of the positioning pin 5 is located is in the range of 0.1 to 0.15 mm. The above diameter difference range is adapted to the gear backlash, so as to minimize the friction between the first planet carrier 4 and the positioning pin 5 under slight vibration.

[0032] Reference Figure 2 , the ratio of the length of the locating pin 5 extending into the first locating hole 41 to the depth of the first locating hole 41 is not less than 80%, for example, 80%, 85%, 90%, 100%. In practical applications, by setting the length of the locating pin 5 extending into the first locating hole 41, the radial positioning requirements of the first planet carrier 4 under different working conditions can be met, thereby avoiding severe vibration.

[0033] Reference Figure 4 The wall of the first positioning hole 41 is provided with an oil groove 42 that penetrates the depth direction of the first positioning hole 41. The wall of the first positioning hole 41 is evenly distributed with a plurality of oil grooves 42. During the operation of the motor transmission structure, the heat caused by the friction between the motor drive shaft 1 and the wall of the first positioning hole 41 can be reduced by passing lubricating oil into the oil groove 42, thereby extending the service life of the motor transmission structure.

[0034] Reference Figure 2, the planetary gear device is installed inside the housing. The housing is provided with a second shaft hole 81 through which the motor drive shaft 1 can pass, and a bearing 9 for limiting and fixing the motor drive shaft 1 is arranged inside the second shaft hole 81. The bearing 9 can support and limit the motor drive shaft 1, thereby ensuring the stability of the rotation of the motor drive shaft 1, and indirectly reducing the possible vibration of the first planet carrier 4. It can be understood that by reducing the vibration between structures, the frictional loss between gears can be further reduced.

[0035] Embodiment 2

[0036] Refer to Figure 2 , the difference between this embodiment and Embodiment 1 is that in this embodiment, a second sun gear 43 is further arranged on one side of the first planet carrier 4 away from the first-stage planetary gear set 3. The planetary gear device further includes a second-stage planetary gear set 6 meshing with the second sun gear 43, and a second planet carrier 7 fixed to the rotating shaft of the second-stage planetary gear set 6. The first positioning hole 41 penetrates through the first planet carrier 4 at the second sun gear 43.

[0037] Refer to Figure 2 and Figure 3 , the second-stage planetary gear set 6 includes a plurality of second planet gears 61 meshing with the second sun gear 43, and a second internal gear ring 62 meshing with the plurality of second planet gears 61. The second planet carrier 7 is fixedly connected to the rotating shafts of the plurality of second planet gears 61. When the motor drive shaft 1 drives the first sun gear 2 to rotate, it can drive a plurality of first planet gears 31 to rotate around the axis of the first sun gear 2, and further drive the first planet carrier 4 to rotate through the plurality of first planet gears 31. The second sun gear 43 of the first planet carrier 4 drives the second planet gears 61 to rotate, and then drives the second planet carrier 7 to rotate.

[0038] Among them, a second positioning hole 71 is formed on the second planet carrier 7. In this embodiment, the positioning pin 5 is also inserted into the second positioning hole 71 and is in clearance fit with the hole wall of the second positioning hole 71.

[0039] Refer to Figure 2 , the first sun gear 2 is provided with a first shaft hole 21 for sleeving the motor drive shaft 1. The first positioning hole 41, the second positioning hole 71, and the first shaft hole 21 are coaxially arranged.

[0040] Therefore, when the motor drive shaft 1 drives the first sun gear 2 to rotate, since the positioning pin 5 is set in clearance fit with both the first positioning hole 41 and the second positioning hole 71, the first planet carrier 4 and the second planet carrier 7 can be radially positioned, thereby further reducing the vibration of the first planet carrier 4 and the second planet carrier 7, and further reducing the overall vibration of the motor transmission structure.

[0041] Embodiment 3

[0042] Refer toFigure 2 The difference between this embodiment and the second embodiment is that, in this embodiment, the positioning pin 5 is only loosely matched with the first positioning hole 41, and is not loosely matched with the second positioning hole 71. Since the first positioning hole 41 is provided on the first planet carrier 4 having the second sun gear 43, and the second sun gear 43 is transmission-connected with the second-stage planetary gear set 6, the second-stage planetary gear set 6 can also be indirectly positioned by positioning the first planet carrier 4 at the first positioning hole 41. Therefore, the motor transmission structure of this embodiment can also ensure the stability of the transmission.

[0043] Reference Figure 1 and Figure 2 An embodiment of the utility model further discloses an electric tool, including a motor and the above-mentioned motor transmission structure transmission-connected to the motor.

[0044] The motor drive shaft 1 and the locating pin 5 of the motor transmission structure can be relatively fixed in a variety of ways. For example, the outer peripheral wall of the locating pin 5 can have a threaded structure and fit into the threaded hole opened on the motor drive shaft 1; for another example, the locating pin 5 can be tightly inserted into the locating hole on the motor drive shaft 1 in an interference fit manner, and the embodiments of the utility model are not limited to this.

[0045] In this embodiment, the positioning pin 5 of the motor transmission structure is formed integrally with the drive shaft 1 of the motor, that is, the positioning pin 5 itself can also serve as a part (extended part) of the motor drive shaft 1.

[0046] In an optional embodiment, the electric tool further comprises a clamping device connected to the motor transmission structure. For example, when the clamping device clamps the drill bit, the motor can drive the clamping device to rotate through the motor transmission structure, thereby driving the drill bit to rotate to complete the drilling work.

[0047] It can be understood that when the electric tool provided with the above-mentioned motor transmission structure is in use, the positioning pin 5 has a positioning effect on the first planetary carrier 4, which can reduce the vibration feeling when the electric tool is used in high-speed gear, thereby optimizing the user experience.

[0048] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0049] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A motor transmission structure, characterized in that: The invention comprises a planetary gear device for connecting to a motor drive shaft (1), the planetary gear device comprising a first sun gear (2) sleeved on the motor drive shaft (1), a first-stage planetary gear set (3) meshing with the first sun gear (2), and a first planet carrier (4) fixing the rotating shaft of the first-stage planetary gear set (3), the first planet carrier (4) being provided with a first positioning hole (41), a positioning pin (5) being inserted into the first positioning hole (41) and being fixed relative to the motor drive shaft (1), the positioning pin (5) being in clearance with the hole wall of the first positioning hole (41).

2. The motor transmission structure according to claim 1, characterized in that: The first positioning hole (41) is configured as a circular hole, and the difference between the diameter of the circular hole and the diameter of the circle where the cross section of the positioning pin (5) is located is in the range of 0.1 to 0.15 mm.

3. The motor transmission structure according to claim 1, characterized in that: The ratio of the length of the positioning pin (5) extending into the first positioning hole (41) to the depth of the first positioning hole (41) is not less than 80%.

4. The motor transmission structure according to claim 1, characterized in that: The first planet carrier (4) is also provided with a second sun gear (43) on a side away from the first-stage planetary gear set (3), and the planetary gear device also includes a second-stage planetary gear set (6) meshing with the second sun gear (43), and a second planet carrier (7) fixed to the rotating shaft of the second-stage planetary gear set (6); A second positioning hole (71) is provided on the second planet carrier (7), and the positioning pin (5) is inserted into the second positioning hole (71) and is clearance-matched with the hole wall of the second positioning hole (71).

5. The motor transmission structure according to claim 4, characterized in that: The first sun gear (2) is provided with a first shaft hole (21) for sleeve-mounting the motor drive shaft (1); the first positioning hole (41), the second positioning hole (71) and the first shaft hole (21) are coaxially arranged.

6. The motor transmission structure according to claim 1, characterized in that: The hole wall of the first positioning hole (41) is provided with an oil groove (42) penetrating the first positioning hole (41) in the depth direction.

7. The motor transmission structure according to claim 6, characterized in that: A plurality of oil grooves (42) are evenly distributed on the hole wall of the first positioning hole (41).

8. The motor transmission structure according to claim 1, characterized in that: The motor transmission structure also includes a housing, the planetary gear device is installed in the housing, the housing is provided with a second shaft hole (81) for the motor drive shaft (1) to pass through, and a bearing (9) is arranged in the second shaft hole (81) for fixing the motor drive shaft (1) in a limited position.

9. An electric tool, characterized in that: It comprises a motor and a motor transmission structure as claimed in any one of claims 1 to 8 which is transmission-connected to the motor.

10. The electric tool according to claim 9, characterized in that: The positioning pin (5) is integrally formed with the driving shaft of the motor.

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