CN211681917U

CN211681917U - Motor and transmission assembly for rotary power tool

Info

Publication number: CN211681917U
Application number: CN201921145680.0U
Authority: CN
Inventors: 刘士春; 廖成才
Original assignee: TTI Macao Commercial Offshore Ltd
Current assignee: TTI Macao Commercial Offshore Ltd
Priority date: 2019-07-19
Filing date: 2019-07-19
Publication date: 2020-10-16
Anticipated expiration: 2029-07-19

Abstract

A rotary power tool (10) includes a housing (12), an output shaft (14) having an axis of rotation (18), a motor (16), and a gearbox assembly (20) containing grease. Wherein the housing (12) has at least one interior space (12c, 12 d). A gearbox assembly (20) containing grease is contained within the interior space (12c, 12 d). The interior space (12c, 12d) is sealed from fluid communication with the remainder of the housing (12). Also, the housing (12) and the gearbox assembly (20) containing grease are fluidly disconnected. The utility model discloses provide sealed inner space in rotary power tool's casing, effectively prevent the pollution that the fluid leakage in the inner space caused other parts.

Description

Motor and transmission assembly for rotary power tool

Technical Field

The present invention relates to power tools, and more particularly to motor and transmission assemblies for rotary power tools, and more particularly to impact drivers for high torque drive applications.

Background

Power tools having a rotary output (e.g., drill bits) typically include a power transmission system having a drive unit and a gearbox assembly to provide speed and torque conversion for a driven member. These power tools are typically used in construction sites, workshops or other locations under extreme conditions. This, in turn, often makes the power tool more difficult to handle and use, as well as repair and maintenance, resulting in a relatively short product life cycle.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to mitigate or eliminate one or more of the problems associated with known power tools to some extent.

The above object is met by a combination of the features of the independent claims; the dependent claims disclose further advantageous embodiments of the invention.

According to the utility model discloses, provide a rotary power tool (10), include:

a housing (12) having at least one interior space (12c, 12 d);

an output shaft (14) having an axis of rotation (18);

a motor (16); and

a gearbox assembly (20) containing grease contained within the interior space (12c, 12 d);

wherein the interior space (12c, 12d) is sealed from fluid communication with the remainder of the housing (12).

Preferably, the housing (12) comprises at least two housing parts (12a, 12b) which, when assembled, together form an inner space (12c, 12d) for enclosing a gearbox assembly (20) containing grease.

Preferably, the tool further comprises a sealing structure (30) surrounding the inner space (12c, 12d) for sealing between each of the two housing parts (12a, 12 b).

Preferably, the sealing structure (30) includes an elastomeric sealing ring (32) located around the gearbox assembly (20) for sealing between the interior space (12c, 12d) and each of the two housing portions (12a, 12 b).

Preferably, an elastic sealing ring (32) is sandwiched between each of the two housing parts (12a, 12 b).

Preferably, one of the housing parts (12a, 12b) comprises a receiving portion (34) for receiving the elastic sealing ring (32).

Preferably, the other of the housing portions (12a, 12b) comprises a protruding portion (36) for abutting against an elastic sealing ring (32) accommodated in the receiving portion (34).

Preferably, the elastic sealing ring (32) is deformed by the protruding portion (36) during assembly, thereby sealing between the inner space (12c, 12d) and the housing portion (12a, 12 b).

Preferably, the resilient sealing ring (32) is deformed by the protruding portion (36) in response to a compressive force applied by the assembly of the two housing portions (12a, 12 b).

Preferably, the protruding portion (36) is separated from the receiving portion (34) by a gap (38) through which the resilient sealing ring (32) is pressed.

Preferably, the protruding portion (36) has a thickness smaller than the opening of the receiving portion (34).

Preferably, the seal between the protruding portion (36) and the receiving portion (34) is enhanced by the pressure exerted by the grease on the elastic sealing ring (32).

Preferably, the protruding portion (36) includes one of a parabolic tip, a tapered tip, an elliptical tip, and a rectangular tip.

Preferably, the rotary power tool (10) further includes a mounting member (80) mounted between the motor (16) and the gearbox assembly (20) such that the motor (16) and the gearbox assembly (20) cannot rotate relative to each other.

Preferably, the mounting member (80) includes a first pair of elongate portions (82), each elongate portion extending from the axis of rotation for mounting the mounting member (80) to the motor (16).

Preferably, the mounting member (80) further includes a second pair of elongated portions (84), each extending from the rotational axis, for mounting the mounting member (80) to the gearbox assembly (20).

Preferably, the first and second pairs of elongate portions (82, 84) extend transversely to one another.

Preferably, the first and second pairs of elongate portions (82, 84) extend in the same plane.

Preferably, the gearbox assembly (20) is provided with fastening means (83, 85) for fixing the mounting member (80) to the gearbox assembly (20) and the motor (16), respectively.

The summary of the invention does not necessarily disclose all features necessary to define the invention; the present invention may reside in a subcombination of the disclosed features.

Drawings

The invention will be described in more detail below with reference to the accompanying drawings, in which:

fig. 1 is a cross-sectional front view of a rotary power tool according to the present invention.

Fig. 2 is a cross-sectional perspective view of a rotary power tool according to the present invention.

Fig. 3 is another cross-sectional perspective view of a rotary power tool according to the present invention.

Fig. 4A is an isometric cross-sectional view of the rotary power tool of fig. 1-3.

Fig. 4B is a plan sectional view of the rotary power tool of fig. 1 to 3.

Fig. 5 is a cross-sectional rear view of a rotary power tool according to the present invention, showing a seal structure of the rotary power tool.

Fig. 6 is a telescopic view of the rotary power tool of fig. 5.

FIG. 7 illustrates a seal structure according to an example embodiment.

Fig. 8 shows a sealing structure according to another example embodiment.

Fig. 9 shows a sealing structure according to another example embodiment.

Fig. 10 shows a sealing structure according to another example embodiment.

FIG. 11 shows a seal structure according to yet another example embodiment.

Fig. 12 is a perspective view of a motor for a rotary power tool.

FIG. 13 is a perspective view of a gear box assembly and motor subassembly for a rotary power tool.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art, as defined by the appended claims. In the drawings, like numbering represents like elements.

A rotary power tool, or more specifically a rotary hammer drill 10, is shown in fig. 1-3. Inside the tool housing 12, there is provided a rotary output shaft 14 which is indirectly driven by a motor 16 having an axis of rotation 18, the motor 16 being powered by a battery 19. The speed and torque output of the motor 16 is modulated by a gear assembly 20. The gear assembly 20 may be housed in a closed arrangement with the impact hammer assembly 22.

Preferably, the hammer assembly 22 receives rotational force from the motor 16 via the gear assembly 20 and, in turn, transmits the modulated rotational force to the output shaft 14. In some other applications, the hammer assembly 22 can also provide intermittent impacts to the same output shaft 14 in situations where high torque is required in certain heavy power tools.

The motor 16 and gearbox assembly 20 are coupled to one another to form a larger subassembly, which is shown in more detail in FIG. 4. The gearbox assembly 20 has a gearbox assembly housing 26 and a gearbox assembly end cap 28, preferably formed by die casting, is coupled to the gearbox assembly housing 26.

These aspects of the gearbox assembly 20 may be a unitary structure, but may also be separate components to facilitate manufacturing and assembly of the gearbox assembly 20. Similarly, the motor 16 also has a motor housing 50 and a motor end cap 60, which may be of unitary construction or composed of separate components that may facilitate manufacture and assembly of the motor 16.

Optionally, metal or plastic may be a suitable material for the gearbox assembly housing 26 and gearbox assembly end cover 28 and for the motor housing 50 and motor end cover 60, but preferably both should preferably be constructed of the same type of material to form a unitary structure to provide the same or other consistent physical properties.

The housing 12 as shown in fig. 5 may be made of at least two or

more housing portions

12a, 12b, e.g., clam shells, that together form the housing 12 having different interior spaces, including a first interior space 12c for enclosing the motor 16, and a second interior space 12d for partially enclosing at least a portion of the shaft 14 and the gearbox assembly 20. The

housing portions

12a, 12b may abut one another along their contact surfaces to provide a plurality of such interior spaces.

To isolate the gearbox assembly 20 containing grease from the rest of the components, a seal structure 30 is also provided for sealing between the second interior space 12d of the enclosed gearbox assembly 20 and the other interior spaces of the housing. By sandwiching the resilient seal ring 32 between the

housing portions

12a, 12b, the second interior space 12d defines a sealed grease seal cavity 31 for receiving the gearbox assembly 20 and ensuring that the gearbox assembly 20 is not in fluid communication with the rest of the housing. This ensures that the grease 23 contained in the gearbox assembly 20 does not leak therefrom, which could otherwise contaminate other components of the rotary hammer drill 10 and thus damage the electrical circuitry of the rotary hammer drill 10.

In one exemplary embodiment as shown in fig. 6, the first housing part 12a constituting the housing cover may include a protruding portion 36, and on the other hand, the second housing part 12b constituting the housing support may include a receiving portion 34, an elastic sealing ring 32 for receiving and a front end of the protruding portion 36.

The resilient sealing ring 32 may preferably be made of an extremely deformable material. The protruding portion 36 may apply a compressive force, e.g., a difference in atmospheric pressure, to the resilient sealing ring as the protruding portion 36 is forced into the receiving portion 34. The elastomeric sealing ring 32 may undergo plastic or elastic deformation and extrude along the front of the nose portion 36, filling the gap 38 between the nose portion 36 and the receiving portion 34.

In an alternative exemplary embodiment, the protruding portion 36 may have a thickness less than the opening of the receiving portion 34, such that the receiving portion 34 and the protruding portion 36 form a void 38 therebetween, thereby providing a passage for the deformed and extruded portions. For example, during compression, elastomeric sealing ring 32 may be forced outwardly along the channel around nose portion 36 to progressively seal the gap 38 between nose portion 36 and receiver portion 34.

Preferably, the projecting portion 36 may have a substantially uniform body, followed by a converging portion and toward its end, a tip portion 40 having a predetermined profile 42. The elastomeric sealing ring 32 may be extruded outwardly within the receiving portion 34 around the contour 42 of the nose portion 36.

In particular, the extent of extrusion of the sealing ring 32 can be controlled by the curvature of the profile 42. For example, a sharp tip 40 may deform the sealing ring 32 to a greater extent, while a rounded tip 40 may deform the sealing ring 32 to a lesser extent. Alternatively, tip portion 40 may be shaped as a parabolic tip (as shown in FIG. 7), an elliptical tip (as shown in FIG. 8), a tapered tip (as shown in FIG. 9 or 10) or a rectangular tip (as shown in FIG. 11) for imparting a different elastic behavior to sealing ring 32.

Advantageously, the grease 23 contained within the gearbox assembly 20 may cooperate with the compressive force exerted on the receiving portion 34 to exert additional oil pressure on the elastomeric seal ring 32 from an outer portion of the elastomeric seal ring 32. This allows the grease 23 to be contained within the cavity 31, i.e., there is no leakage of the grease 23, and the grease 23 may also serve as an auxiliary means of enhancing the seal between the

housing portions

12a, 12b and the gearbox assembly 20.

Turning now to the detailed construction of the transmission system, the motor 16 is provided with a rotary shaft 62 on a major face of the motor end cap 60 for driving the gear 61 along a rotary axis 64 and, in turn, the driven gear 21 and the actuating shaft 14 of the gear box assembly 20. During operation of the rotary hammer 10, the movable components, such as the motor 16 and the gearbox assembly 20, are each subjected to severe vibration, and thus the drive gear 61 and the driven gear 21 may be subjected to undesirable impact forces and excessive wear therebetween.

To improve the overall durability of the motor 16 and gearbox assembly 20, the present invention provides various means for mounting the motor 16 to the gearbox assembly 20, thereby reducing their relative motion and thus reducing the overall vibration and instability of the hammer 10. For example, a mounting member 80 may be provided for mounting between the motor 16 and the gearbox assembly 20 such that the motor 16 and gearbox assembly 20 are substantially non-rotatable relative to each other.

In one exemplary embodiment, the mounting member 80 may be manufactured to provide two pairs of

elongated portions

82, 84, each pair of

elongated portions

82, 84 extending from the axis of rotation 64. The first pair of elongated portions 82 are mounted to the motor end cap 60 by fastening means 83, such as screws. On opposite sides of the mounting member 80, a second pair of elongated portions 84 are mounted to the gearbox assembly end cover 28 by fastening means 85, e.g. screws, the second pair of elongated portions 84 preferably extending from the rotational axis 64 and in a direction transverse to the direction of extension of the elongated portions 82. Optionally, the first and second pairs of

elongated portions

82, 84 extend in the same plane to reduce shear forces exerted on the mounting member 80 due to vibrations during operation.

The present invention is advantageous in that the mounting member 80 stabilizes the interface and limits vibration and stress on the housing 12 during impacts that may occur when the hammer assembly 22 or an external object acts on the rotating shaft 14. The more complementary the

elongated portions

82, 84 are to the motor end cover 60 and gearbox assembly end cover 28, i.e., the more rotational and vibrational movement between the two movable components may be reduced by the securement of the mounting member 80 between the motor 16 and gearbox assembly 20.

Advantageously, the mounting member 80 of the rotary tool 10 is provided with one or more additional elongated portions 82', 84' extending from the axis of rotation 64, and respective fastening means 83', 85' for fastening the additional pairs of elongated portions 82', 84' to the motor end cover 60 and the respective gearbox assembly end cover 28, respectively. Having additional

elongated portions

82, 84 may provide further stability to the interface of the motor 16 and gearbox assembly 20, even with less vibration.

Various features of the invention are set forth in the following claims.

In the claims which follow and in the preceding description of the invention, unless the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

It will be understood that, if any prior art publication is referred to herein, it does not constitute an admission that the publication forms part of the common general knowledge in the art in australia, china, france, germany or any other country.

Claims

1. A rotary power tool (10), characterized by comprising:

a housing (12), the housing (12) having at least one interior space (12c, 12 d);

an output shaft (14), the output shaft (14) having a rotational axis (18);

a motor (16); and

a gearbox assembly (20) containing grease, the gearbox assembly (20) contained within the interior space (12c, 12 d);

2. The rotary power tool (10), according to claim 1, characterized in that the housing (12) comprises at least two housing parts (12a, 12b) which, when assembled, together form an inner space (12c, 12d) for enclosing a gearbox assembly (20) containing grease.

3. The rotary power tool (10) according to claim 2, wherein the rotary power tool (10) further comprises a seal structure (30) surrounding the interior space (12c, 12d) for sealing between each of the two housing portions (12a, 12 b).

4. A rotary power tool (10), according to claim 3, characterized in that said sealing structure (30) includes an elastic sealing ring (32) located around said gearbox assembly (20) for sealing between said inner space (12c, 12d) and each of the two housing parts (12a, 12 b).

5. The rotary power tool (10), according to claim 4, characterized in that the resilient sealing ring (32) is sandwiched between each of the two housing portions (12a, 12 b).

6. The rotary power tool (10), according to claim 4, characterized in that one of the housing portions (12a, 12b) includes a receiving portion (34) for receiving the resilient seal ring (32).

7. The rotary power tool (10), according to claim 6, characterized in that the other of the housing portions (12a, 12b) includes a protruding portion (36) for abutting against the resilient sealing ring (32) received in the receiving portion (34).

8. The rotary power tool (10), according to claim 7, characterized in that the resilient sealing ring (32) is deformed by the protruding portion (36) during assembly to seal between the interior space (12c, 12d) and the housing portion (12a, 12 b).

9. The rotary power tool (10), according to claim 7, characterized in that the resilient sealing ring (32) is deformed by the protruding portion (36) in response to a compressive force applied by the assembly of the two housing portions (12a, 12 b).

10. The rotary power tool (10), according to claim 7, characterized in that the protruding portion (36) is separated from the receiving portion (34) by a gap (38) through which the resilient seal ring (32) is pressed.

11. The rotary power tool (10), according to claim 7, characterized in that the thickness of the protruding portion (36) is smaller than the opening of the receiving portion (34).

12. The rotary power tool (10), according to claim 7, characterized in that the seal between the protruding portion (36) and the receiving portion (34) is enhanced by the pressure exerted on the elastic sealing ring (32) by grease.

13. The rotary power tool (10), according to claim 7, characterized in that the protruding portion (36) includes one of a parabolic tip, a conical tip, an elliptical tip and a rectangular tip.

14. The rotary power tool (10) according to any one of claims 1 to 13, wherein the rotary power tool (10) further comprises a mounting member (80) mounted between the motor (16) and the gearbox assembly (20) such that the motor (16) and gearbox assembly (20) cannot rotate relative to each other.

15. The rotary power tool (10), according to claim 14, characterized in that said mounting member (80) includes a first pair of elongated portions (82), each extending from said axis of rotation for mounting said mounting member (80) to said motor (16).

16. The rotary power tool (10), according to claim 15, characterized in that said mounting member (80) further includes a second pair of elongated portions (84), each extending from said axis of rotation for mounting said mounting member (80) to said gearbox assembly (20).

17. The rotary power tool (10), according to claim 16, wherein said first and second pairs of elongated portions (82, 84) extend transversely to one another.

18. The rotary power tool (10), according to claim 16, characterized in that said first and second pairs of elongated portions (82, 84) extend in the same plane.

19. The rotary power tool (10), according to claim 14, characterized in that said gearbox assembly (20) is provided with fastening means (83, 85) for securing said mounting member (80) to said gearbox assembly (20) and motor (16), respectively.