JP2001225254A - Sander - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress the rotation of a sanding disk with its internal gear in a freely rotating state. SOLUTION: A sun gear 27 provided with teeth 28, 28, etc, on its outer circumference is integrally fitted on the periphery of a connecting shaft 21 eccentrically installed on a lower end of a spindle 14. On the outer side of the gear 27 and in a position close to an opening part of a lower housing 5, the internal gear 29 of a diameter larger than that of the gear 27 is supported coaxially with the spindle 14 by a ball bearing 32. The teeth 28 of the eccentrically positioned gear 29 partly mesh with teeth 30 formed on the inner circumference of the gear 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sander for causing a polishing disk provided below a main body housing to perform a combined movement of a rotational movement and an eccentric movement, so-called orbital movement.

[0002]

2. Description of the Related Art A conventional sander is disclosed in, for example,
As disclosed in Japanese Patent No. 7810, a connection shaft having an eccentric shaft is connected to a spindle which is supported downward in the body housing, and a polishing disk is fixed to the connection shaft. Is exteriorized. On the other hand, in the main body housing, an internal gear into which the sun gear is loosely inserted and meshes is fixed. Therefore, when the spindle rotates with the drive of the motor in the main body housing, the connecting shaft eccentrically moves, and the sun gear that eccentrically moves integrally with the connecting shaft meshes with the internal gear, so that the connecting shaft rotates and the polishing disk is rotated. Have an orbital exercise. Especially here,
The momentum is large because the polishing disk is forcibly rotated by the sun gear meshing with the internal gear,
Since the internal gear is not suitable for finish polishing, the internal gear is rotatably mounted inside the main body housing, and the main body housing has a stopper pin that can be locked to the internal gear and an operation knob that can slide the stopper pin. By providing a locking mechanism that allows the rotation of the internal gear by sliding the stopper pin accompanying the operation of the operation knob, the rotation of the polishing disk is suppressed by the frictional force between the internal gear and the inner surface of the main body housing. It has been disclosed.

[0003]

In the above sander,
Since there is no intervening object between the outer circumference of the internal gear and the inner circumference of the main body housing, in the free rotation state of the internal gear, only the meshing resistance with the sun gear is generated, and the effect of suppressing the rotation of the polishing disk is sufficient. Can not be obtained.
On the other hand, a rotation suppressing force can be expected when the internal gear in the free rotation state contacts the main body housing. However, since the magnitude of this suppressing force is determined by the processing dimensions of the internal gear, high processing accuracy is required. If the processing accuracy is low, the suppression force varies. Further, with the contact with the main body housing, the internal gear may generate heat or wear due to friction, and the wear may cause a reduction in the suppressing force.

Accordingly, the first aspect of the present invention provides a sander not only capable of effectively suppressing the rotation of the polishing disk in the free rotation state of the internal gear but also free from heat generation and wear. It is intended for that purpose.

[0005]

According to a first aspect of the present invention, the internal gear is supported by a bearing in the main body housing. . The invention described in claim 2 has, in addition to the object of claim 1, in order not to cause inclination even when an external force is applied to the internal gear and to obtain good operability,
The bearing is a ball bearing.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial vertical cross-sectional view of a random orbit sander (hereinafter referred to as “sander”). A main housing 2 of the sander 1 has a first metal housing 3 assembled with upper and lower divided housings 4 and 5. When,
A second housing 6 made of synthetic resin and attached from the front surface of the first housing 3 (the left side of FIG. 1 is described as the front).
A motor housing 8 having a built-in motor 9 is connected to the rear of the main body housing 2. The output shaft 10 of the motor 9 is supported by a disc-shaped plate 11 closing the front of the motor housing 8 via a ball bearing 12 so as to protrude into the first housing 3, and a first bevel gear 13 is integrally fixed to a tip thereof. are doing. In the first housing 3, a spindle 14 is vertically supported by ball bearings 15 and 16, and a second bevel gear 17 integrally mounted at an intermediate position of the spindle 14 meshes with the first bevel gear 13. The rotation of the output shaft 10 can be transmitted to the spindle 14.

An eccentric shaft 18 eccentric from the center of rotation is projected from the lower end of the spindle 14, and a sleeve 19 is integrally fitted to the eccentric shaft 18, and ball bearings 20, 20 are attached to the sleeve 19. The connection shaft 21 is coaxially fitted through the through hole. At the lower end of this connecting shaft 21, a bolt 2
2, the base 23 is connected, and the polishing disk 24 is fixed to the lower surface of the base 23. Reference numerals 25 and 26 denote balance weights. The balance weight 25 rotates integrally with the spindle 14 in the lower housing 5 and the balance weight 26 rotates in the upper housing 4. Also, the connecting shaft 21
A sun gear 27 having teeth 28, 28,... Provided on the outer periphery is integrally fitted to the outer periphery of the lower housing 5 at the outer periphery of the lower portion of the lower housing 5 at the outer periphery of the sun gear 27. Internal gear 29 is ball bearing 32
A part of the teeth 28 of the sun gear 27 at the eccentric position meshes with teeth 30 formed coaxially with the spindle 14 and formed on the inner periphery of the internal gear 29. A plurality of recesses 31 and 3 are provided above the outer peripheral surface of the internal gear 29.
Are recessed at equal intervals.

Then, on the left side of the main body housing 2,
As shown in FIG. 2, the locking mechanism 33 of the internal gear 29
Is provided. The locking mechanism 33 includes an operation knob 35 mounted on a cylindrical portion 34 protruding from a side surface of the lower housing 5.
And a stopper pin 40 that protrudes and retracts into the lower housing 5 in accordance with the turning operation of the operation knob 35. First, the operation knob 35 is rotatably fitted to the cylindrical portion 34 and the screw 3
The flange 37 is formed so as to be gradually thickened in a quarter turn around the outer edge of the outer portion of the operation knob 35 to the cylindrical portion 34. On the other hand, in the lower housing 5, a through hole 39 is formed between the internal gear 29 and the operation knob 35, and the recess 3 is formed in the through hole 39.
A cylindrical stopper pin 40 that can be fitted into 1 is loosely inserted into the lower housing 5 slidably in a radial direction orthogonal to the axial direction of the internal gear 29. A guide pin 42 is loosely inserted into the stopper pin 40 from behind (from the disk portion 38 side of the operation knob 35), and a coil spring 44 is provided between the front inside the stopper pin 40 and the flange 43 at the rear end of the guide pin 42. With the bias of the coil spring 44,
The tip of the stopper pin 40 is urged toward the concave portion 31 of the internal gear 29, and the guide pin 42 is urged in the direction opposite to the direction in which the flange 43 abuts against the disk portion 38.

However, a stopper piece 41 protrudes upward from the rear end of the stopper pin 40 and is engaged with the flange 37 of the operation knob 35. A knob projection 45 provided outside the operation knob 35 is provided. In the locking position where the horizontal position is horizontal, the stopper piece 41 is locked to the thinnest portion of the flange 37, and the stopper pin 40 moves to the forward position where it engages with the concave portion 31 of the internal gear 29 (see FIG. 2). Position), 4 from there
At the unlocking position where the knob projection 45 rotated by one-half turn is vertical, the stopper piece 41 is guided by the inclination of the flange 37 and locked to the thickest part, and the stopper pin 40 is connected to the internal gear 29. The forward movement is restricted at the retracted position (the position shown by the two-dot chain line in FIG. 2) away from the concave portion 31 of FIG. A steel ball 46 urged toward the first housing 3 by a coil spring 47 is provided on the back side of the disk portion 38.
The click action is obtained by fitting into the concave portions 48, 48 formed in the upper and lower housings 4, 5.

On the other hand, as shown in FIGS. 3 and 4, the rear end of the second housing 6 substantially covers the connecting portion between the first housing 3 and the motor housing 8, and the lower front half thereof is the first housing. The second housing 6 is covered so as to completely cover the front surface of the lower housing 3, and the lower rear portion of the lower housing 5 is exposed on both side surfaces thereof (the left side surface is cut away along the shape of the operation knob 35). ing. A space 49 is formed between the first housing 3 and the second housing 6 as shown in FIGS. And the parts to be adhered to each other are in a sealed state.
Only the gap 50 formed near the center of both sides between the housing 3 and the second housing 6 communicates with the outside. Reference numeral 51 denotes a fan fixed to the output shaft 10 of the motor 9 in the motor housing 8, and includes a baffle plate 52 for covering the blade portion of the fan 51 from behind, and a fan 51.
When the fan 51 is rotated by the through holes 53 formed in the plate 11 and the upper housing 4 on the outer periphery of the motor housing 8, outside air is sucked in from an intake hole (not shown) provided behind the motor housing 8, and 53, 53...

When the operation knob 35 of the locking mechanism 33 is rotated to the locking position where the knob protrusion 45 is horizontal, the sander 1 configured as described above, as described above,
Is locked to the thinnest portion of the flange 37, the stopper pin 40 projects to the forward position, and fits into the recess 31 of the internal gear 29.
Rotation is regulated. Therefore, when the motor 9 is driven in this state, the first bevel gear 1
3 and the second bevel gear 17 mesh with each other to rotate the spindle 1
4 rotates, and the eccentric shaft 18 at the lower end thereof and the connecting shaft 21 which supports the eccentric shaft 18 revolve, that is, eccentrically move, and the polishing disk 24 at the lower end of the connecting shaft 21 eccentrically moves. Here, the teeth 28 of the sun gear 27 eccentrically moving integrally with the connecting shaft 21 mesh with the teeth 30 of the internal gear 29, so that the connecting shaft 21 rotates, that is, the rotational movement is forcibly generated. Similarly, it is rotated. Therefore, the polishing disk 24 performs the orbital movement of the rotational movement and the eccentric movement, and the operator holds the motor housing 8 with one hand and the protrusion 7 in front of the second housing 6 with the other hand. Polishing can be performed by supporting the sander 1 and pressing the polishing disk 24 against the work.

Next, when the operation knob 35 of the locking mechanism 33 is rotated to the unlocked position where the knob projection 45 is vertical, the stopper piece 41 is locked to the thickest portion of the flange 37. Then, the stopper pin 40 retreats and separates from the concave portion 31 of the internal gear 29, so that the rotation of the internal gear 29 becomes free. Therefore, when the motor 9 is driven here, the connection shaft 21 and the polishing disc 24
Occurs in the same manner as described above, but with the eccentric movement of the connecting shaft 21, the connecting shaft 21 tries to rotate the internal gear 29 by following the meshing resistance between the sun gear 27 and the internal gear 29. Therefore, the rotational movement of the connecting shaft 21 and the polishing disk 24 is suppressed. Therefore, here, polishing can be performed by a combination of the eccentric motion of the polishing disk 24 and the suppressed rotational motion.

On the other hand, as the output shaft 10 rotates, the fan 51
Is rotated, the air taken into the motor housing 8 cools the motor 9 and the through holes 53,
Flows into the space 49 through 53. However, space 4
9 is closed by the second housing 6 so that air flows right and left along the inner surface shape of the second housing 6 and is discharged from the gaps 50 formed between the first housing 3 and the side surface. Is done. Therefore, warm air does not hit the hands of the worker holding the protrusion 7 of the second housing 6.

As described above, according to the sander 1 of the above embodiment,
By forming the recess 31 on the outer periphery of the internal gear 29 and arranging the stopper pin 40 on the outer periphery of the internal gear 29 so as to be slidable in a direction perpendicular to the axial direction thereof,
In order to provide the balance weight 25, the stopper pin 40 can be arranged using the space formed in the lower housing 5 as it is. Therefore, the size of the main body housing 2 is not changed by the locking mechanism 33, the compactness of the main body housing 2 can be maintained, and the cost increase due to the use of the locking mechanism 33 can be minimized.

Further, since the internal gear 29 is supported by the ball bearing 32 in the lower housing 5, when the internal gear 29 rotates freely, the follow-up rotation of the internal gear 29 becomes a resistance and the connecting shaft 21 In addition, the rotation of the polishing disk 24 can be effectively suppressed. Further, since the internal gear 29 does not contact the lower housing 5, heat generation and wear due to friction can be prevented. In particular, since the ball bearing 32 is used as the bearing, the internal gear 29 is stable, and the shaft does not tilt even when an external force is applied in the radial direction, so that good operability can be secured.

Since the cooling air is exhausted from the gaps 50 on both sides without providing an exhaust hole on the front surface of the second housing 6, the worker's hand holding the projecting portion 7 of the second housing 6 can be used. No hot air is blown on the surface, and the occurrence of discomfort can be prevented. Also, the second housing 6 made of synthetic resin
Is attached so as to cover the front surface of the sander 1, the operator's hand does not touch the first housing 3 that has been heated by use, and the generation of discomfort of the operator due to the heat generated by the first housing 3 occurs. Can also be prevented.

The number of ball bearings supporting the internal gear is not limited to one, and a plurality of ball bearings can be stacked in the axial direction. The bearing of the internal gear is not limited to the ball bearing, and other forms such as a needle bearing and a metal bearing can be selected as long as the internal gear can be supported in the main body housing.

[0018]

According to the first aspect of the present invention, since the internal gear is supported by the bearing in the main body housing, when the internal gear rotates freely, the follow-up rotation of the internal gear is reduced in resistance. And joined the connecting shaft,
The rotation of the polishing disk can be effectively suppressed.
Further, since the internal gear does not contact the main body housing, heat generation and wear due to friction can be prevented. According to the second aspect of the present invention, in addition to the effect of the first aspect, the use of the ball bearing as the bearing stabilizes the internal gear and causes the shaft to tilt even when an external force is applied in the radial direction. And good operability can be ensured.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a sander.

FIG. 2 is a sectional explanatory view of a locking mechanism.

FIG. 3 is an explanatory left side view of the sander.

FIG. 4 is a right side explanatory view of a sander.

[Explanation of symbols]

1. Random orbit sander 2. Body housing 3. First housing 4. Upper housing 5.
· Lower housing, 6 · · · second housing, 9 · · · motor · 10 · · output shaft, 14 · · spindle, 18 · · · eccentric shaft, 21 · · · connecting shaft, 24 · · · polishing disc, 27 ·
· Sun gear, 29 · · · internal gear, 31 · · · recess, 32 · · · ball bearing, 33 · · · locking mechanism, 3
5 ··· Operation knob, 40 ·· Stopper pin, 49 ·· Space, 50 ·· Gap, 51 ·· Fan.

Claims (2)

[Claims] 1. A body which is pivotally supported downward in a main body housing,
A spindle that is rotationally driven by a motor, a connection shaft connected to the spindle at an eccentric position, and a polishing disk fixed to the connection shaft, while the outer periphery of the connection shaft is provided with a sun gear, A sander in which an internal gear in which the sun gear is loosely inserted and meshes is rotatably disposed, wherein the internal gear is supported by a bearing in the main body housing. 2. The bearing according to claim 1, wherein the bearing is a ball bearing.
Sander described in.