WO2014133229A1 - Housing structure of gear box for electric tool - Google Patents

Abstract

The present invention relates to a gear box for an electric tool and, more specifically, to a coupling structure of an external housing for fixing a ring gear in a gear box to which a planetary gear connected with a motor of an electric tool is applied. To this end, the housing structure of the gear box, according to the present invention, is a gear box for an electric tool, comprising: a cylindrical housing body (100) having a housing body opening (110) provided at one end thereof; a housing cap (200) coupled with the housing body opening (110); and a ring gear (300) which is an internal gear coupled with the housing cap (200) so as to be fixed to the inside of the housing body (100), wherein a plurality of grooves (310) are formed on a lateral surface of an outer circumference of the ring gear (300) and a plurality of protrusions (220) coupled with the grooves (310) are formed on a lateral surface of an inner circumference of the housing cap (200).

Description

Housing structure of gearbox of power tool

The present invention relates to a gearbox of a power tool, and more particularly to a structure of a gearbox housing for fixing a ring gear in a gearbox to which a planetary gear connected to a motor of the power tool is applied.

In general, power tools use electric power as a power source through a wire or battery to drive the built-in motor to rotate a tool that is selectively coupled according to the purpose of use, such as a driver and a drill. It is one of the tools that can be.

The motor used for the power tool rotates at high speed and lacks torque, which is a tightening force to perform the work directly. Therefore, the motor has a structure in which a sufficient speed is obtained by connecting the reduction gear to the motor to lower the rotation speed.

The higher the motor's reduction ratio, the larger torque can be obtained. When the gear reducer of the general gear type is applied, the power transmission ratio per unit volume decreases, so when the high reduction ratio is obtained, the volume of the reducer becomes large, and as a result, the volume of the power tool is too large. There is a problem.

In particular, in the case of a rechargeable power tool that uses a battery as a power source, since portability is required, a gearbox type that reduces speed by applying a planetary gear type in order to obtain small size, light weight and high reduction ratio is provided.

Referring to FIG. 1, a planetary gearbox includes a ring gear 20, which is an internal gear fixed in a gearbox housing 10 having a cylindrical shape, and a sun gear disposed at an axis of the ring gear 20. A plurality of planetary gears (not shown) are arranged between the ring gears and the sun gears (not shown).

Therefore, in the gearbox housing 10, since a plurality of gears are engaged with each other and continuously rotated at high speed, heat and noise are generated due to friction, so that a lubricant such as grease is filled.

Such lubricants may cause malfunctions of other electrical devices when they leak out of the gearbox housing, or may cause inconvenience in use when they come out of the power tool case. Consequently, lack of lubricant in the gearbox housing may cause lubrication effects and cause noise and breakage. Therefore, it is important that the gearbox housing has a sealed structure.

In addition, the ring gear 20, which is an internal gear fixed in the gearbox housing 10, is a fixed portion directly coupled to the housing, and thus the ring gear 20 frequently moves relative to the planetary gear in the gearbox housing. Stable coupling in the housing 10 is required.

Furthermore, since the power tool has the same output and the lighter and smaller size is more convenient to use, it is necessary to miniaturize the gearbox and the miniaturization in the axial length direction and the circumferential direction is a major consideration in design.

The circumference of the gearbox can be reduced in size by miniaturizing the internal gear, but there is a limit depending on the basic size and reduction ratio of the internal planetary gear itself, so an idea for miniaturizing the gearbox in the axial direction is required.

The fixing of the ring gear 20 in the conventional gearbox housing 10 forms a protrusion 21 in the gearbox housing axial direction in the ring gear 20 and the recess 31 in the gearbox housing cap 30 corresponding thereto. It is common to have a structure that forms a) and meshes with one another.

In this case, since a minimum distance is required to form protrusions and recesses in the gearbox housing axial direction, it is necessary to improve this as a negative factor in miniaturization in the gearbox axial direction.

Furthermore, since the ring gear and the planetary gear inside the gearbox rotate at high speed and repeat forward and reverse rotation, a means for mitigating shock due to vibration and rotation moment is required.

The present invention has been made in view of the above-mentioned point, and the gearbox housing structure of the power tool having a stable fixing structure of the ring gear to secure the sealing of the gearbox housing in the gearbox of the power tool and to realize the miniaturization The purpose is to provide.

The gearbox housing structure of the power tool according to the present invention for achieving the above technical problem is, in the gearbox of the power tool, a cylindrical housing body 100 having a housing body opening 110 at one end, the housing body opening ( A housing cap 200 coupled to the housing 110 and a ring gear 300 coupled to the housing cap 200 and fixed to the inside of the housing main body 100, and an outer circumference of the ring gear 300. A plurality of grooves 310 are formed at a side surface, and a plurality of protrusions 220 are formed at an inner circumferential side of the housing cap 200 to correspond to the grooves 310.

In addition, the housing cap 200 is formed with a circular housing cap insertion portion 210 which is coupled to the outer peripheral surface in close contact with the inner peripheral surface of the housing body opening 110, the outer peripheral surface of the ring gear 300 is the housing cap It is characterized in that the close contact with the inner peripheral surface of the insertion portion 210.

Furthermore, a buffer member 400 is further disposed between the groove 310 of the ring gear 300 and the protrusion 220 of the housing cap 200 in the circumferential direction of the ring gear 300. do.

The gearbox housing structure of the power tool according to the present invention made as described above has a plurality of grooves on the outer circumferential side of the ring gear and a protrusion on the inner circumferential side of the housing cap, whereby the ring gear is stably fixed inside the housing while in the gearbox axial direction. There is an advantageous effect to downsizing.

In addition, in the gearbox, the housing body opening, the housing cap insertion portion, and the ring gear are coupled to each other in the circumferential direction so that the housing cap and the housing body have a structure that is advantageous for stable coupling and sealing.

Furthermore, by reducing the vibration transmitted to the ring gear and the housing main body by the buffer member between the groove portion and the protrusion, it is possible to provide a power tool that extends the life of the gear box and realizes low noise.

1 is a schematic view showing a gearbox housing structure of a conventional power tool.

2 is a view showing a ring gear in the gearbox housing structure of the power tool according to an embodiment of the present invention.

3 is a view for explaining the gearbox housing structure of the power tool according to an embodiment of the present invention.

4 is a view for explaining the coupling correlation in the gearbox housing structure of the power tool according to an embodiment of the present invention.

5 is a view for explaining the structure applied to the elastic member in the gearbox housing structure of the power tool according to an embodiment of the present invention.

Advantages and features of the present invention, and methods for accomplishing the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. Hereinafter, a gearbox housing structure of a power tool according to an embodiment of the present invention will be described with reference to the accompanying drawings.

2 and 3, the gearbox housing structure of the power tool according to an embodiment of the present invention is a cylindrical housing body 100, one end of which is opened in the gearbox of the power tool, the housing body 100 And a housing gear 200 coupled to one end of the ring gear 300 and an internal gear fixed to the housing body 100 by coupling with the housing cap 200.

The housing body 100 is generally a cylindrical member having a housing body opening 110 open at one end. The housing body 100 accommodates a plurality of planetary gears and a sun gear ring gear therein and becomes a case of a power tool gearbox.

The housing cap 200 has a circular housing cap inserting portion 210 inserted into the housing body opening 110 in a circular cap shape, and an outer circumferential surface of the housing cap inserting portion 210 is formed in the housing body opening. Closely coupled to the inner circumferential surface of the 110 to seal the housing body 100.

The ring gear 300 is a circular internal gear that is generally disposed at the outermost part of a gearbox of a power tool. A sun gear (not shown) is disposed at an axis of the ring gear 300 and the ring gear 300 is disposed. ) And a plurality of planetary gears (not shown) are engaged between the sun gear and the sun gear.

As described above, since the ring gear 300 should be stably fixed to the gearbox housing of the power tool, a plurality of grooves 310 are formed on the outer circumferential side of the ring gear 300, and the housing cap 200 is provided. The inner circumferential side of the plurality of protrusions 220 are formed to be coupled to correspond to the groove portion 310 can be fixed to each other by coupling.

This structure has the advantage of shortening the axial length of the gearbox housing body as compared to the conventional structure in which a ring gear is formed and fixed to the projection coupled to the housing cap in the axial direction of the housing body.

In addition, the protrusions 220 corresponding to the plurality of grooves 310 are radially symmetrically disposed with respect to the axis center of the ring gear 300 so that when the force is applied in the forward or reverse direction, the ring gear ( 300) can be fixed.

4, the outer circumferential surface of the ring gear 300 is closely coupled to the inner circumferential surface of the housing cap inserting portion 210, so that the housing cap inserting portion 210 has an inner ring gear 300. It has a structure supported by the outer peripheral surface of the outer peripheral direction.

In addition, the outer circumferential surface of the housing cap inserting portion 210 has a structure to seal the gearbox housing by screwing or tightly coupled to the inner circumferential surface of the housing body opening 110.

Accordingly, the outer circumferential surface of the housing cap inserting portion 210 is fixedly supported in the inner circumferential direction by the housing body opening 110, and the inner circumferential surface is tightly coupled in the outer circumferential direction toward the housing main body 100 by the ring gear 300. Since it is supported by (see FIG. 4 arrow), there is an advantage in the stable coupling and sealing with the housing body 100 of the housing cap 200.

Referring to FIG. 5, a buffer member 400 is further disposed between the groove 310 of the ring gear 300 and the protrusion 220 of the housing cap 200 in the circumferential direction of the ring gear 300. As a result, the ring gear 300 may reduce vibration transmitted to the housing when the forward rotation is repeated by the internal planetary gear.

Accordingly, the groove 310 of the ring gear 300 may be provided in various forms including a space for disposing the shock absorbing member 400. The groove 310 of the ring gear 300 may be inserted to correspond to the groove 310. The shape of the protrusion 220 may also be in various forms.

The buffer member 400 may be generally provided as an elastic member such as rubber, but a synthetic resin or similar various materials may be applied according to the durability and use form of the gearbox.

In addition, the shock absorbing member 400 may be provided in various shapes in which the shock absorbing effect may be expected not only in the circumferential circumferential direction of the ring gear 300 (FIG. 5A) but also in the axial direction (FIG. 5B). .

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. will be.

Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following detailed description, and the scope and meaning of the claims And all changes or modifications derived from the equivalent concept should be construed as being included in the scope of the present invention.

Claims (3)

In the gearbox of the power tool, A cylindrical housing body 100 having a housing body opening 110 at one end; A housing cap 200 coupled to the housing body opening 110; And And a ring gear 300 which is coupled to the housing cap 200 and is an internal gear fixed to the inside of the housing body 100. A plurality of grooves 310 are formed on the outer circumferential side of the ring gear 300, and a plurality of protrusions 220 are formed on the inner circumferential side of the housing cap 200 to correspond to the groove 310. Gearbox housing structure of power tools. The method of claim 1, The housing cap 200 is formed with a circular housing cap insertion portion 210 that is coupled to the outer peripheral surface in close contact with the inner peripheral surface of the housing body opening 110, An outer circumferential surface of the ring gear 300 is in close contact with the inner circumferential surface of the housing cap inserting portion 210, the gear box housing structure of the power tool. The method according to claim 1 or 2, Transmission between the groove 310 of the ring gear 300 and the protrusion 220 of the housing cap 200 further includes a shock absorbing member 400 disposed in the circumferential direction of the ring gear 300. Gearbox housing structure of the tool.

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