KR20240096956A - Gear box of a power tool - Google Patents

Abstract

The content disclosed in this specification relates to a gearbox, and more specifically, to a gearbox that can be compactly reduced in size by reducing the space inside the gearbox installed in a power tool. A cylindrical gearbox housing with an opening on one side, a ring gear that is an internal gear adjacent to one side of the gearbox housing and coupled to the inside of the gearbox housing, and a ring gear that engages the ring gear and moves in the circumferential direction of the ring gear. a planetary gear that rotates along the planetary gear, a carrier that is connected to the planetary gear and rotates around its central axis as the planetary gear rotates, and a sun gear disposed in the inner space of the carrier and engaged with the planetary gear. , a first bearing coupled to the outer peripheral surface of the sun gear to support the sun gear, a second bearing coupled to the outer peripheral surface of the carrier to support the carrier, and a receiving space in which the second bearing is accommodated, and the gear box. A gearbox coupled to one side of the housing and including a rear cap accommodating the second bearing is presented as an embodiment of the present invention.

Description

Gear box{Gear box of a power tool}

The content disclosed in this specification relates to a gearbox, and more specifically, to a gearbox that can be compactly reduced in size by reducing the space inside the gearbox installed in a power tool.

Unless otherwise indicated herein, the matters described in this identification are not prior art to the claims of this application, and are not acknowledged to be prior art by being described in this identification.

Power tools are tools used for various tasks, such as loosening or tightening screws, using the power of a built-in electric motor. Power tools are tools that have become so common that they are used not only in industrial settings but also in ordinary homes. Power tools generally consist of a drive motor built into the main body, a reduction unit consisting of a gear that changes and transmits the rotational speed of the motor, a spindle, an impactor, an anvil, etc. The reduction unit may include a plurality of planetary gears, sun gears, and ring gears inside. Power tools can be made up of a modular gearbox that accommodates a reduction unit, spindle, impactor, anvil, etc. to improve assembly.

The power tool may include a plurality of bearings, such as a first bearing coupled to the rotating shaft of the drive motor and a second bearing coupled to a carrier coupled to the planetary gear. These bearings support the rotating shaft and carrier of the drive motor. In the prior art, the first bearing and the second bearing are installed to be spaced apart in the longitudinal direction, and the second bearing is accommodated in a rear cap coupled to one side of the gearbox. The rear cap is provided with a first bearing and a space to accommodate the first bearing. When the first and second bearings are installed in this way, they are installed spaced apart from each other along the longitudinal direction, and as a separate accommodation space is required in the rear cap, the gearbox becomes longer in length. Due to this installation structure, the power tool has a problem in that the length in the axial direction of the drive motor becomes longer. As shown in FIG. 1, it can be seen that this problem is caused by the bearings 72 installed spaced apart from each other in the prior art (Korean Patent Publication No. 10-2003-0031451) and the space in which the bearings 72 are accommodated. there is.

In order to miniaturize and lighten power tools, a method is required to reduce the size of the gearbox by changing its internal structure.

Republic of Korea Patent Publication No. 10-2003-0031451 (published on April 21, 2003) Republic of Korea Patent Publication No. 10-2014-0029472 (published on March 10, 2014) Republic of Korea Patent No. 10-0800041 (announced on January 31, 2008)

The present invention was conceived to solve the above problems, and its purpose is to provide a gearbox that enables miniaturization and weight reduction of electric tools by changing the combination and arrangement structure of the bearings that make up the gearbox of the electric tool. do.

In order to solve the above problems, the present invention provides the following gearbox.

A cylindrical gearbox housing with an opening on one side, a ring gear that is an internal gear adjacent to one side of the gearbox housing and coupled to the inside of the gearbox housing, and a ring gear that engages the ring gear and moves in the circumferential direction of the ring gear. a planetary gear that rotates along the planetary gear, a carrier that is connected to the planetary gear and rotates around its central axis as the planetary gear rotates, and a sun gear disposed in the inner space of the carrier and engaged with the planetary gear. , a first bearing coupled to the outer peripheral surface of the sun gear to support the sun gear, a second bearing coupled to the outer peripheral surface of the carrier to support the carrier, and a receiving space in which the second bearing is accommodated, and the gear box. A gearbox coupled to one side of the housing and including a rear cap accommodating the second bearing is presented as an embodiment of the present invention.

Additionally, the first bearing may be coupled to the inner peripheral surface of the carrier, and the first bearing and the second bearing may be arranged to overlap along the longitudinal direction.

In addition, the sun gear is detachably coupled to the rotation axis of the drive motor, a first locking protrusion on which one side of the first bearing is caught is formed on the outer circumferential surface, and the carrier is a second locking protrusion on which the other side of the first bearing is caught on one inner circumferential surface. A snag may be formed.

In addition, the sun gear is detachably coupled to the rotation axis of the drive motor, a first locking protrusion on which one side of the first bearing catches is formed on the outer peripheral surface, and is coupled to a groove formed on one inner peripheral surface of the carrier, and the first locking protrusion is formed on the outer peripheral surface of the first bearing. It may further include a fixing ring attached to the other side of the first bearing to limit longitudinal movement of the first bearing.

Additionally, the sun gear may be formed integrally with the rotation shaft of the drive motor. The carrier may have a second locking protrusion formed on one inner peripheral surface to which the other side of the first bearing rests. It may further include a fixing ring that is coupled to a groove formed on one inner peripheral surface of the carrier and faces the other side of the first bearing to limit longitudinal movement of the first bearing. It is coupled through the central portion of the rear cap, and a flange may be formed to protrude in the radial direction on one outer peripheral surface.

According to the problem solving means of the present invention as discussed above, various effects including the following can be expected. However, the present invention does not require all of the following effects to be achieved.

The gearbox according to an embodiment of the present invention has the effect of reducing the size of the power tool by coupling the first bearing to the sun gear.

In addition, the plurality of installed bearings are arranged overlapping along the longitudinal direction, which has the effect of dramatically reducing the size of the power tool.

In addition, as the rotation axis of the drive motor and the sun gear are formed as one piece, the internal structure of the carrier is simplified and the manufacturing cost of the carrier is reduced.

1 is a cross-sectional view of a power tool according to the prior art;
Figure 2 is a perspective view showing a gearbox according to an embodiment of the present invention;
Figure 3 is an exploded perspective view of Figure 2;
Figure 4 is a cross-sectional view taken along line IV-IV' of Figure 2;
Figure 5 is a cross-sectional view showing the gearbox of the present invention including a sun gear formed integrally with the rotation shaft of the drive motor;
Figure 6 is a cross-sectional view showing a gearbox of the present invention including a first bearing with a flange.
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Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 is a cross-sectional view of a power tool according to the prior art, Figure 2 is a perspective view showing a gearbox according to an embodiment of the present invention, Figure 3 is an exploded perspective view of Figure 2, and Figure 4 is a cut line IV-IV' of Figure 2. Figure 5 is a cross-sectional view showing the gearbox of the present invention including a sun gear formed integrally with the rotation axis of the drive motor, and Figure 6 is a cross-sectional view showing the gearbox of the present invention including a first bearing with a flange. am.

In the drawings and description of the present invention, when each component is combined, the anvil side to which the tool is coupled is positioned at the front, and the electric motor side is positioned at the rear. The longitudinal direction of the components constituting the present invention refers to the direction in which each component extends from one end to the other end, and coincides with the front or rear when each component is combined.

As shown in these drawings, the gearbox 10 of the present invention is characterized by a combination and arrangement structure of the first bearing 600 and the second bearing 700. In addition, it is characterized by a structure for limiting the longitudinal movement of the sun gear 500, and the sun gear 500 and the rotation axis 22 of the drive motor are formed integrally. Therefore, in the present invention, only content related to the features of the present invention will be described in detail, and detailed description of content related to the configuration, function, and structure of other general power tools will be omitted.

Referring to FIGS. 2 to 4, the gearbox 10 according to an embodiment of the present invention reduces the rotational speed of the drive motor as necessary to efficiently perform tool work, and has an open side on one side. A cylindrical gearbox housing 100, a ring gear 200, which is an internal gear adjacent to one side of the gearbox housing 100 and coupled to the inside of the gearbox housing 100, and a ring gear 200. A planetary gear 300 that engages and rotates along the circumferential direction of the ring gear 200, and a carrier 400 that is connected to the planetary gear 300 and rotates around the central axis as the planetary gear 300 rotates. ), a sun gear 500 disposed in the inner space of the carrier 400 and engaged with the planetary gear 300, a first bearing 600 coupled to the outer peripheral surface of the sun gear 500 and supporting the sun gear 500, and , a second bearing 700 coupled to the outer peripheral surface of the carrier 400 to support the carrier 400, and a receiving space 810 in which the second bearing 700 is accommodated, and the gearbox housing 100 It is coupled to one side and may include a rear cap 800 that accommodates the second bearing 700. Meanwhile, according to one embodiment of the present invention, the gearbox 10 may further include a fixing ring 900 that limits the longitudinal movement of the first bearing 600.

The gearbox housing 100 includes a ring gear 200, a planetary gear 300, a sun gear 500, a carrier 400, a first bearing 600, a first bearing 600, and a ring gear 200 that reduces the rotational speed of the drive motor as necessary. Configurations such as two bearings 700 are installed, and it is preferable that they are formed as a single module unit to improve assembly of the power tool. Since the gearbox 10 can be formed as a single module unit, if the component accommodated inside the gearbox 10 needs to be replaced due to damage or inability, only the gearbox 10 can be replaced, allowing for assembly and use of power tools. Convenience of replacement can be improved. The gearbox housing 100 may be formed in a cylindrical shape with one side open. A rear cap 800, which will be described later, is coupled to one side of the opening, and a motor box 20 consisting of a drive motor, a rotation shaft 22, a rotor, etc. is coupled. A ring gear 200, a planetary gear 300, a sun gear 500, a carrier 400, a first bearing 600, and a second bearing 700 can be accommodated inside the gearbox housing 100, and may be accommodated as necessary. Accordingly, configurations such as the spindle 1000, impactor 1100, anvil 1200, and spring 1300 may be further accommodated. The gearbox housing 100 may be installed integrally within the main housing of the power tool or may be installed protruding outside the main housing.

The ring gear 200 coupled to one side of the gearbox housing 100 meshes with the planetary gear 300 to reduce the rotational speed of the drive motor as necessary, and may be formed as an internal gear. By arranging the ring gear 200 as close as possible to one side of the gearbox housing 100 where the opening is formed, the separation distance between one side of the gearbox housing 100 and the motor box 20 can be reduced to a minimum. A sun gear 500 is disposed at the center of the ring gear 200, and a planetary gear 300 is disposed between the ring gear 200 and the sun gear 500. That is, the teeth of the planetary gear 300 engage with the teeth formed in the inner circumferential direction of the ring gear 200.

The planetary gear 300 engaged with the ring gear 200 serves as an intermediate gear connecting the sun gear 500 and the ring gear 200, and may be formed as an external gear. The planetary gear 300 may be composed of a set of 2 to 5 pieces, and the same set may be formed of the same size. The planetary gear 300 engages with the ring gear 200 as the sun gear 500 rotates and is driven to rotate along the circumferential direction of the ring gear 200. As the planetary gear 300 is driven to rotate along the circumferential direction of the ring gear 200, the carrier 400 coupled to the planetary gear 300 also rotates. As the carrier 400 rotates, the spindle 1000 also rotates, and eventually the tool coupled to the anvil 1200 also rotates.

The carrier 400, which is connected to the planetary gear 300 and driven to rotate, rotates integrally with the spindle 1000. The carrier 400 rotates around a central axis and is coupled to a second bearing 700, which will be described later, and is supported by the second bearing 700. A second bearing 700 is coupled to the outer surface of the carrier 400. When the second bearing 700 is a rolling bearing, the carrier 400 is coupled to the inner ring of the second bearing 700 and driven to rotate. Since the carrier 400 is located in the internal space of the ring gear 200, the carrier 400 is also located adjacent to one side of the gearbox housing 100 where the opening is formed. Accordingly, the carrier 400 may be coupled to the second bearing 700 accommodated in the rear cap 800, which will be described later, and supported by the second bearing 700.

The sun gear 500 disposed in the internal space of the carrier 400 transmits the rotational force of the drive motor and may be formed as an external gear. The sun gear 500 is coupled to the rotation shaft 22 of the drive motor and may be meshed with the planetary gear 300. As the rotation shaft 22 of the drive motor is inserted and coupled to the sun gear 500, the gearbox and motor box 20 can be easily assembled. The sun gear 500 is coupled with a first bearing 600, which will be described later, and is supported by the first bearing 600. In the past, as the bearing was coupled to the rotating shaft of the drive motor, space was needed in the rear cap to accommodate the bearing, which led to the problem of the gearbox becoming longer. However, in the present invention, as the sun gear 500 is coupled to the first bearing 600, the space where the first bearing 600 is accommodated in the rear cap 800 can be eliminated. The rear cap 800, which does not form a space to accommodate the first bearing 600, may be shortened in length, and the rear cap 800 shortened in the longitudinal direction is coupled to the gearbox housing 100. Ultimately, the overall length of the gearbox housing 100 is shortened, so the power tool can be miniaturized.

The first bearing 600 coupled to the outer peripheral surface of the sun gear 500 serves to support the sun gear 500 and may be formed of various types of bearings such as sliding bearings or rolling bearings. The first bearing 600 is coupled to the sun gear 500 and may be coupled to the carrier 400 or the rear cap 800. That is, the inner peripheral surface of the first bearing 600 is in contact with the outer peripheral surface of the sun gear 500, and the outer peripheral surface of the first bearing 600 is in contact with the carrier 400 or the rear cap 800 and can be coupled. As the first bearing 600 is coupled to the sun gear 500, the space where the first bearing 600 is accommodated in the rear cap 800 is removed, so the length of the gearbox housing 100 can be shorter than before. there is. The shortened gearbox 10 ultimately enables miniaturization and weight reduction of the power tool.

The second bearing 700 coupled to the outer peripheral surface of the carrier 400 serves to support the carrier 400 and may be formed of various types of bearings such as sliding bearings or rolling bearings. As the rear cap 800 is coupled to the gearbox housing 100, the second bearing 700 is accommodated in the receiving space 810 provided in the rear cap 800 and its position is fixed. The second bearing 700 may be fixed so as not to move between the rear cap 800 and the carrier 400 by ring-shaped fixing members 1400 on both sides. That is, the fixing member 1400 prevents the second bearing 700 from leaving its coupled position. The second bearing 700 can form an organic arrangement relationship with the first bearing 600, which will be described later, and the gearbox housing 100 is formed by the organic arrangement relationship between the first bearing 600 and the second bearing 700. ) can be shorter than before. The shortened gearbox 10 ultimately enables miniaturization and weight reduction of the power tool.

The rear cap 800 coupled to one side of the gearbox housing 100 seals the gearbox housing 100, and a through hole 820 is formed in the center, and the rotation axis of the drive motor is formed in the through hole 820. (22) can be inserted through. The rear cap 800 has an accommodation space 810 corresponding to the shape of the second bearing 700 and can accommodate the second bearing 700. Fixing members 1400 may be coupled to both sides of the accommodation space 810 where the second bearing 700 is accommodated. The fixing members 1400 coupled to both sides of the receiving space 810 may prevent the second bearing 700 from moving from the coupled position. The first bearing 600 on which the flange 610, which will be described later, is formed, may be coupled to the through hole 820 of the rear cap 800. In this case, the first bearing 600 on which the flange 610 is formed is caught in the center of the rear cap 800, and forward movement may be restricted. That is, the position of the first bearing 600 is fixed while covering the central part of the rear cap 800, and movement into the inside of the gearbox housing 100 is restricted.

The first bearing 600 and the second bearing 700 may be arranged to overlap along the longitudinal direction. The first bearing 600 is coupled to the outer circumferential surface of the sun gear 500, but may be coupled to the inner circumferential surface of the carrier 400 while being in contact with the first bearing 600. In this case, the position where the first bearing 600 is coupled may be close to the second bearing 700. That is, as the first bearing 600 is located in the internal space of the second bearing 700, the first bearing 600 and the second bearing 700 are located on the same plane in the form of a concentric circle based on the same central axis. You can. In this case, a portion of the carrier 400 is simultaneously supported by the first bearing 600 and the second bearing 700. The carrier 400 may be supported while being in contact with the outer peripheral surface of the first bearing 600 and the inner peripheral surface of the second bearing 700. Additionally, since the first bearing 600 and the second bearing 700 are not spaced apart in the longitudinal direction, the length of the gearbox housing 100 can be dramatically shortened. Accordingly, as the length of the gearbox housing 100 becomes shorter, the size of the power tool may become smaller.

The rotation shaft 22 of the drive motor and the sun gear 500 can be detachably coupled, and the sun gear 500 can be moved forward in the coupled state. In order to prevent the sun gear 500 from moving forward, a first locking protrusion 510 that catches one side of the first bearing 600 may be formed on the outer peripheral surface of the sun gear 500. The first locking protrusion 510 protrudes from the outer peripheral surface of the sun gear 500 and may be formed along the circumferential direction. Meanwhile, a reaction force may be generated when the sun gear 500 is caught by the first bearing 600, and this reaction force may cause the first bearing 600 to move forward from the coupled position. In order to prevent the first bearing 600 from moving forward, a second locking protrusion 420 that catches the other side of the first bearing 600 may be formed on one inner peripheral surface of the carrier 400. The first locking protrusion 510 can prevent the forward movement of the sun gear 500 and at the same time interact with the second locking protrusion 420 to prevent the first bearing 600 from moving forward. Meanwhile, the present invention may further include a fixing ring 900 in place of the second locking protrusion 420. The fixing ring 900 is coupled to the groove 430 formed on one inner peripheral surface of the carrier 400 and faces the other side of the first bearing 600, thereby limiting the forward movement of the first bearing 600. The fixing ring 900 has a hollow shape through which the sun gear 500 can pass, and can be in various ring shapes, such as a snap ring. The fixing ring 900 is preferably a snap ring in order to be easily installed in the groove 430.

Referring to Figure 5, in a gearbox according to an embodiment of the present invention, the sun gear 500 and the rotation shaft 22 of the drive motor may be formed integrally. That is, one end of the drive motor rotation shaft 22 may be formed of a sun gear 500 having teeth. In this case, compared to the case where the sun gear 500 and the rotation axis 22 of the drive motor are separate, the configuration such as the first locking protrusion 510 to limit the forward movement of the sun gear 500 is unnecessary. Since the rotation shaft 22 of the drive motor is fixed on the drive motor side, the sun gear 500 formed integrally with the rotation shaft 22 does not move forward. However, since forward movement of the first bearing 600 supporting the sun gear 500 must be prevented, the present invention provides a second locking protrusion on which the other side of the first bearing 600 hangs on one inner peripheral surface of the carrier 400 described above. 420 may be formed, and may further include a fixing ring 900 that is coupled to the groove 430 formed on one inner peripheral surface of the carrier 400 and faces the other side of the first bearing 600.

Additionally, referring to FIG. 6, when the sun gear 500 is formed integrally with the rotation shaft 22 of the drive motor, the first bearing 600 is through-coupled with the through hole 820 in the central portion of the rear cap 800. A flange 610 may be formed to protrude in the radial direction on one outer peripheral surface. As the flange 610 is caught on the rear cap 800, the forward movement of the first bearing 600 is restricted. In this case, the above-described second locking protrusion 420 or fixing ring 900 becomes unnecessary. When the first bearing 600 with the flange 610 is formed, the internal structure of the carrier 400 is simplified, which has the effect of reducing the manufacturing cost of the carrier 400.

As seen above, the gearbox 10 according to an embodiment of the present invention has the effect of reducing the size of the power tool by coupling the first bearing 600 to the sun gear 500. In addition, the plurality of installed bearings are arranged overlapping along the longitudinal direction, which has the effect of dramatically reducing the size of the power tool. In addition, as the rotation shaft 22 of the drive motor and the sun gear 500 are formed integrally, the internal structure of the carrier 400 is simplified and the manufacturing cost of the carrier 400 is reduced.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the embodiments described in this specification and the configuration shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention. Since this is not the case, it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the claims described later rather than the detailed description, and the meaning and scope of the claims and their All changes or modified forms derived from the equivalent concept should be construed as falling within the scope of the present invention.

10: Gearbox
20: Motor box
22: rotation axis
100: Gearbox housing
200: Ring gear
300: planetary gear
400: Carrier
420: Second locking jaw
430: Home
500: Sun gear
510: First locking jaw
600: 1st bearing
610: Flange
700: Second bearing
800: Rear cap
810: Accommodation space
820: Through hole
900: Fixing ring
1000: Spindle
1100: Impactor
1200: Anvil
1300: spring
1400: Fixing member

Claims (8)

A cylindrical gearbox housing (100) with one side open;
A ring gear 200, which is an internal gear adjacent to one side of the gearbox housing 100 and coupled to the inside of the gearbox housing 100;
A planetary gear 300 engaged with the ring gear 200 and driven to rotate along the circumferential direction of the ring gear 200;
A carrier 400 that is connected to the planetary gear 300 and rotates around its central axis as the planetary gear 300 rotates.
A sun gear 500 disposed in the inner space of the carrier 400 and engaged with the planetary gear 300;
A first bearing 600 coupled to the outer peripheral surface of the sun gear 500 and supporting the sun gear 500;
A second bearing 700 coupled to the outer peripheral surface of the carrier 400 and supporting the carrier 400; and
A rear cap 800 that includes a receiving space 810 in which the second bearing 700 is accommodated, is coupled to one side of the gearbox housing 100, and accommodates the second bearing 700;
A gearbox comprising:
In claim 1,
A gearbox, wherein the first bearing 600 is coupled to the inner peripheral surface of the carrier 400, and the first bearing 600 and the second bearing 700 are arranged to overlap along the longitudinal direction.
In claim 2,
The sun gear 500 is detachably coupled to the rotation shaft 22 of the drive motor, and a first locking protrusion 510 on which one side of the first bearing 600 catches is formed on the outer peripheral surface,
The carrier 400 is a gearbox characterized in that a second locking protrusion 420 is formed on one inner peripheral surface to which the other side of the first bearing 600 rests.
In claim 2,
The sun gear 500 is detachably coupled to the rotation shaft 22 of the drive motor, and a first locking protrusion 510 on which one side of the first bearing 600 catches is formed on the outer peripheral surface,
A fixing ring 900 that is coupled to the groove 430 formed on one inner peripheral surface of the carrier 400 and faces the other side of the first bearing 600 to limit the longitudinal movement of the first bearing 600. ;
A gearbox further comprising:
In claim 1,
The sun gear 500 is a gearbox characterized in that it is formed integrally with the rotation shaft 22 of the drive motor.
In claim 5,
The carrier 400 is a gearbox characterized in that a second locking protrusion 420 is formed on one inner peripheral surface to which the other side of the first bearing 600 rests.
In claim 5,
A fixing ring 900 that is coupled to the groove 430 formed on one inner peripheral surface of the carrier 400 and faces the other side of the first bearing 600 to limit longitudinal movement of the first bearing 600. ;
A gearbox further comprising:
In claim 5,
The first bearing 600 is,
A gearbox characterized in that it is coupled through a central portion of the rear cap (800) and a flange (610) is formed to protrude in the radial direction on one outer peripheral surface.

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