JP3268042B2 - Tightening tool with silent clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power type fastening tool for screws, and more particularly, to a power tool having a clutch and a stopper sleeve.
The present invention relates to a silent clutch-equipped fastening tool that, when a screw is tightened to a predetermined depth, a clutch is disconnected to stop screwing, and even if the motor continues to rotate, the clutch runs quietly and does not generate noise.

[0002]

2. Description of the Related Art A known fastening tool with a silent clutch is disclosed in Japanese Patent Publication No. 3-5952. This tool has the following configuration.
FIG. 1 of the publication is referred to as FIG. 11 in this specification. This tool includes a drive motor (not shown), a clutch 58, a spindle 51, and a stopper sleeve 52 as main components inside a housing 50.

[0003] A pinion 59 attached to the output shaft of the drive motor penetrates the partition wall 60 of the housing 50 and extends to the working space below in the figure. In this working space, a spindle 51 is arranged in parallel with the pinion 59.

The spindle 51 is supported by a ring-shaped bearing 53 at the upper end in the figure and by a stopper sleeve 52 at the lower side in the figure so as to be rotatable and slidable in the axial direction. The bearing 53 is mounted so as to be buried to the middle of the partition wall 60 in the thickness direction.
As shown, a space 61 is formed by the bearing 53, the partition wall 60, and the upper end surface of the spindle 51. The space 61 serves as a space for sliding the spindle 51, and the space 61 is airtightly sealed so that foreign matter does not enter from the drive motor side.

A meshing clutch 58 composed of three clutch elements 55, 56, 57 is mounted on the small diameter portion of the spindle 51, and a driver bit 54 is mounted on the tip of the large diameter portion. It has become.

According to this structure, the clutch 51 is engaged or disconnected by sliding the spindle 51 in the axial direction, whereby the rotational force of the drive motor is transmitted to the driver bit 54 or cut off. ing.

[0007]

However, according to the above-mentioned conventional structure, the space 61 reserved for sliding the spindle 51 is surrounded by the upper end surface of the spindle 51 in the figure, the bearing 53, and the partition wall 60. As the spindle 51 slides, the air in the space 61 is pressurized or depressurized, so that the spindle 51 slides smoothly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and a space for a spindle slide can be air-tightly separated from a drive motor to prevent foreign matter from entering the space. An object of the present invention is to provide a fastening tool with a silent clutch that can slide smoothly.

[0009]

According to the present invention, there is provided a stopper sleeve provided at a distal end portion of a housing, a driving gear rotated by a driving device, and a driver bit located in the stopper sleeve. A spindle supported movably in the axial direction, and a meshing clutch mechanism operated by the axial movement of the spindle to transmit rotation to the spindle from the drive gear and block the rotation transmission. a clamping tool with the space which is surrounded by the bearing member and the housing for supporting the spindle and the spindle, is constantly atmosphere and communicating via the communication means provided in said spindle, front
Suction and exhaust by the axial movement of the spindle
Characterized in that it was.

[0010]

According to this structure, since the space is separated from the drive motor by the housing, it is possible to prevent foreign matter from entering the space from the drive motor. In addition, since this space is communicated with the atmosphere by the communication means, it is not airtightly sealed, so that the spindle slides smoothly.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electric screw driver according to an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 1 denotes a housing, in which a motor 2, a clutch CL and a spindle 10 are housed. In the figure, reference numeral 19 denotes a stopper sleeve,
The stopper sleeve 19 is attached to the housing 1. The stopper sleeve 19 is slidable in the axial direction with respect to the housing 1 and can be fixed at an arbitrary position. A trigger 3 is mounted on the housing 1 so as to be operable by an operator, and while the trigger 3 is being pulled, a current is supplied to the motor 2 to rotate. Housing 1
Nine air holes 4 on one side at the position surrounding the motor 2
a to 4 i are formed to cool the motor 2. As shown in FIG. 2, each of the air holes 4a to 4i is biased toward the trigger 3, and cooling air is blown toward the trigger 3 as indicated by an arrow. That is, no cooling air is blown out above the XX line in the figure. Here, during normal work, the face of the operator is located above the XX line. That is, in this tool, the direction of the air holes 4a to 4i is devised so that the cooling air does not directly hit the face of the operator.

As best shown in FIG. 1, the spindle 10 is rotatably and axially slidably supported by ring-shaped bearing metals 8, 16 fixed to the housing 1. The housing rear end side of the bearing metal 8 through the space portion 7 of the axial movement of the sp e command <br/> le 10 1
Of the motor 2 to prevent foreign matter from entering the space 7 from the motor 2 side. The rear end side surface of the spindle 10 has two chamfered surfaces 9 in the diameter direction,
9 to form a chamfer 9
Extends forward from the front end of the bearing metal 8. For this reason, the space 7 is always in the atmosphere (gear chamber) through the gap between the chamfered surface 9 and the bearing metal 8 even if the spindle 10 is retracted.
(See FIG. 3). Therefore, the spindle 10
Slides lightly in the bearing metal 8. For the conventional structure without the chamfer 9, bearing metal 8 and has the spindle 10 and the partition wall 1 space 7 which is surrounded by the a is sealed, the air in here is sometimes pressurized or reduced pressure And the spindle 10 did not slide smoothly.

A drive gear 1 is provided around the spindle 10.
1 is freely rotatably fitted. The drive gear 11 is pressed against the bearing 25 by a spring SP described later.
Do not slide in the axial direction. A gear 11a is formed on the outer periphery of the drive gear 11, and this gear 11a
And the pinion 6a formed on the output shaft 6 of the motor. The output shaft 6 is supported by bearings 5. Thereby, the drive gear 11 is rotated around the spindle 10 by the motor 2.

On the front end face of the drive gear 11, grooves 20 are formed at three places on the same radius (see FIGS. 4 to 6).
The groove 20 has a diameter of 2 of the steel ball 12 described later.
It is twice as long, and its depth is constant. The end in the circumferential direction is finished in a shape that comes into contact with the steel ball 12 in a planar manner. 5 and 6 show the grooves 20, 20,
20 shows a shape when developed along a circumference connecting the centers of 20. Since the drive gear 11 does not need clutch teeth, it does not receive a large load and is made of sintered metal. For this reason, production costs are kept low.

As shown in FIG. 1, an intermediate clutch member 13 is disposed in front of the drive gear 11 so as to face the same. The intermediate clutch member 13 is the spindle 1
It is loosely fitted around 0, is rotatable with respect to the spindle 10, and is slidable in the axial direction. The intermediate clutch member 13 is biased toward the drive gear 11 by a spring SP.

Three grooves 21 are formed on the rear end surface of the intermediate clutch member 13 so as to face the three grooves 20, 20, and 20. This is shown in detail in FIGS. As is apparent from the figure, the groove 21 is
Longer than. 6, the depth (the length in the axial direction) is the largest at the center 21a of the groove 21, and the slope is gradually reduced on both sides (21).
b), and the end face 21c has a shape that comes into contact with the steel ball 12 in a planar manner. A steel ball 12 is interposed between the grooves 20 and 21. The steel ball 12 is a ball and prevents the grooves 20 and 21 from rotating independently. However, since the ball 12 is loosely interposed in the grooves 20 and 21, the grooves 20 and 21, that is, the drive gear 11 and the intermediate clutch member 13 can relatively rotate within a predetermined range. FIG. 5 shows a state in which the ball (steel ball 12) is located at the center 21a of the groove 21, while FIG. 6 shows a state in which the ball (steel ball 12) is located at the left end of the groove 21 and at the right end of the groove 20. Is shown.

In the state shown in FIG.
Since the depth 1 is the deepest, the drive gear 11 and the intermediate clutch member 13 come closest to each other. In contrast, in the state of FIG. 6, the steel ball 12 moves to a position where the depth of the groove 21 is shallow, so that the intermediate clutch member 13 is moved away from the drive gear 11. That is, it is pushed forward. If the depth difference of the groove 21 is B, the intermediate clutch member 13 is pushed out of the drive gear 11 by B only when the state of FIG. It is sufficient that the length of the groove 20 is at least the diameter of the steel ball 12. In this embodiment, the steel ball 12 is used as a ball in order to obtain a smooth movement. However, the ball need not always be a sphere.

As shown in FIG. 1, clutch teeth 14 are formed on the front end surface of the intermediate clutch member 13,
On the rear end surface of the large diameter portion 10a of the spindle 10, clutch teeth 15 are formed. The clutch teeth 14 and 15 can be engaged. Silent clutch CL is configured mainly of the drive gear 11 and the intermediate clutch member 13 and the scan steel ball 12 operates as described below. Note the tip end of the spindle 10 is formed a shaft hole 17, wherein the de Raibabitto 18 is made attachable. When the driver bit 18 is attached, the driver bit 1
8 rotates together with the spindle 10 in the stopper sleeve 19.

Next, the operation of the tool will be described with reference to FIGS. First, the motor 2 does not rotate and the driver bit 1
8 is not pressed against the screw, as shown in FIG.
The spindle 10 is pushed forward by a spring SP, and the intermediate clutch member 13 is urged to the drive gear 11 by the spring SP. At this time, since no torque acts between the drive gear 11 and the intermediate clutch member 13, the drive gear 11
The intermediate clutch member 13 and the intermediate clutch member 13 are located closest to each other, that is, as shown in FIG. Since the chamfered surfaces 9 and 9 are formed at the rear end of the spindle 10 and the space 7 is communicated with the atmosphere, the spindle 10 is smoothly pushed forward without any resistance by the spring SP.

In this state, when the operator presses the tool against the work, the spindle 10 is driven through the driver bit 18.
Recedes (see change from FIG. 7 to FIG. 8). Also at this time, since the space 7 is communicated with the atmosphere by the chamfered surface 9, the spindle 10 smoothly retreats. When the spindle 10 moves backward, the clutch teeth 14, 1
5 meshes. Now, with the motor 2 rotating, the spindle 1
Considering the case where 0 retreats, the clutch teeth 14 and 15 begin to mesh at an intermediate stage between FIG. 5 and FIG. Here, as is apparent from a comparison between FIG. 5 and FIG. 6, although the drive gear 11 largely moves (ie, rotates) to the left, the intermediate clutch member 13 does not move (ie, rotates). That is, the clutch teeth 14 and 15 can be engaged at a stage where the rotation speed of the intermediate clutch member 13 is lower than that of the drive gear 11. For this reason, the clutch teeth 14 and 15 mesh at a gentle speed, and after meshing, they are rotated at a high speed, and the load acting on the clutch teeth 14 and 15 is reduced.
That is, when the clutch teeth 14 and 15 mesh with each other, the intermediate clutch member 13 moves relative to the rotational direction of the drive gear 11.
While rotating in the opposite direction, the rotation speed is reduced to mesh with the spindle 10, whereby the clutch teeth 14, 15 are smoothly meshed, and the durability of the clutch teeth is improved. The length of the groove 20 serves to allow the relative rotation of the drive gear 11 and the intermediate clutch member 13, and the longer the length, the longer the time required for the intermediate clutch member 13 to start rotating at high speed. Although the length of the inclined surface 21b of the groove 21 may be increased, it cannot be unnecessarily increased as long as the groove 21 extends in the circumferential direction. Therefore, it is advantageous to increase the length of the groove 20.

The clutch teeth 14 and 15 meshed with a force against the intermediate clutch member 13 to rotate is increased, pushing the steel ball 12 in the illustrated right end of the groove 20, the inclined surface of the steel ball 12 is a groove 21 Roll 21b.
For this reason, the intermediate clutch member 13 is pushed forward by the change B in the depth of the groove 21. Then, screw tightening proceeds in this state. This state is shown in FIG.

As is clear from FIG. 1, when the tip of the stopper sleeve 19 contacts the work W, the force of the operator pressing the tool against the work W is the force of the stopper sleeve 19 pressing the work W. The force pushing the spindle 10 forward is only the force of the spring SP. In this state, when the screw is advanced and the clutch teeth 14 and 15 are disengaged from each other, the intermediate clutch member 13 can rotate freely, and as a result, the state of FIG. Return to

As a result, a clearance of only B is generated between the clutch teeth 14 and 15, and the clutch teeth 14 and 15 are formed.
Idles quietly without making noise. That is, the state returns to the state of FIG. When the operator presses the driver bit 18 again to the next screw, the clutch is engaged in the state of FIG. 8, the screw tightening proceeds in the state of FIG. 9, and when the screw tightening proceeds to the set depth, the state of FIG. The operation of returning is repeated.

Next, a case where the remaining margin is retightened will be described. Now, it is assumed that the clearance between the clutch teeth in FIG. 7 is B, and the remaining margin is less than B. In this case, even if the driver bit 18 is brought into contact with the untightened screw and the driver bit 18 is retracted, the stopper sleeve 19 is moved before the clutch teeth 15 are retracted by the distance B and the clutch teeth 14 and 15 are engaged. It will contact W. Therefore, as shown in FIG. 8, the clutch teeth 14 and 15 do not mesh. For this reason, it was not possible to retighten the screws that were left behind with conventional tools. If the screw is left untightened with a conventional tool, the stopper sleeve 19 must be retracted and retightened so that the state shown in FIG. 8 can be realized.

However, according to the tool of this embodiment, once the trigger 3 is loosened, the motor 2 is stopped, the driver bit 18 is brought into contact with the screw which has not been tightened, and the trigger 3 is operated to rotate the motor 2. 9 is realized, and retightening is possible. Once the motor 2
Is stopped, the drive gear 11 and the intermediate clutch member 13
No torque acts between them, and as shown in FIG. 5, the steel ball 12 is located at the deepest point 21a, and the intermediate clutch member 13 is most retracted. Even if the driver bit 18 is pressed against the remaining screw in this state, the clutch teeth 14 and 15 cannot be engaged as shown in FIG. Even if the remaining tightening is just equal to the clearance B, the clutch teeth 14 and 15 will approach each other just before they start to mesh with each other, and if the remaining tightening allowance is small, the clearance will remain between the clutch teeth 14 and 15. Would.

In this embodiment, however, when the trigger 3 is operated and the motor 2 is started to move, the intermediate clutch member 13 has inertia and cannot rotate suddenly. 21, the intermediate clutch member 13 is pushed forward. For this reason, the state of FIG. 9 is realized without passing through the state of FIG. 8, and in this state, the remaining part can be retightened.

As described above, according to the configuration of the present embodiment, the space 7 is constantly communicated with the atmosphere by the chamfered surfaces 9, 9 formed on the spindle 10, so that the space 7 is moved with the slide of the spindle 10. The space 7 is not pressurized or depressurized, so that the spindle 10 smoothly advances or retracts, and the engagement or disconnection of the clutch is performed smoothly.

In this embodiment, the case where the chamfered surface 9 is formed as the communicating means has been exemplified. However, the present invention is not limited to this. For example, as shown in FIG. A T-shaped through-hole 9a may be formed at the end so that the space 7 and the atmosphere side are always in communication, and a groove 9b is formed instead of the chamfered surface 9 as shown in FIG. It may be that.

A groove 20 having a constant depth is provided on the drive gear 11 side, and a groove 21 having a variable depth is provided on the intermediate clutch member 13 side. However, this may be reversed or a V-shaped groove . In the present embodiment or, although the grooves 20 and 21 provided at three places equal intervals in the circumferential direction, the number of grooves 20, 21 may be any number of 1 or more. Further, in the present embodiment, the spindle 10 also serves as the shaft of the clutch CL, but the shaft of the clutch unit may be separate from the spindle 10. Many other variations are possible.

[0030]

According to the present invention, the space surrounded by the spindle, the bearing member for supporting the spindle, and the housing is always air-tightly communicated by the communication means, so that the space is not airtightly sealed. Therefore, the spindle slides smoothly. Moreover, since this space is separated from the drive motor side by the housing,
Foreign matter is prevented from entering the space from the drive motor side.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of one embodiment.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partially enlarged cross-sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is an exploded view of the drive gear, the intermediate clutch member, and the spindle (however, no torque is applied).

FIG. 6 is an exploded view of the drive gear, the intermediate clutch member, and the spindle (in a state where torque is applied).

FIG. 7 is a diagram showing the relationship between the drive gear, the intermediate clutch member and the spindle in the axial direction (however, no torque is applied and the tool is not pressed against the work).

FIG. 8 is a diagram showing the relationship between the drive gear, the intermediate clutch member, and the spindle in the axial direction (however, no torque is applied and the tool is pressed against the workpiece).

FIG. 9 is a diagram showing a relationship between an axial direction of a drive gear, an intermediate clutch member and a spindle (however, torque is applied and a tool is pressed against a workpiece).

FIG. 10 is a partial cross-sectional side view of a spindle end provided with another communication means.

FIG. 11 shows an example of a conventional tightening tool.

[Explanation of symbols]

 Reference Signs List 1 housing 1a partition wall 2 motor 8 bearing metal 9 chamfered surface 9a through hole (communication means) 9b groove (communication means) 10 spindle 11 drive gear 12 steel ball (ball) 13 intermediate clutch member 14 clutch teeth (intermediate clutch member) 15 clutch Tooth (spindle) 18 Driver bit 19 Stopper sleeve 20 Groove 21 Groove 21b Inclined surface with different depth CL Clutch SP Spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-219581 (JP, A) JP-A-4-76381 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B25B 23/157

Claims (1)

(57) [Claims] 1. A stopper sleeve mounted on a distal end of a housing, a drive gear rotated by a driving device, and a driver bit positioned in the stopper sleeve, and are supported movably in the axial direction. A tightening tool comprising: a spindle; and a meshing clutch mechanism that is operated by moving the spindle in the axial direction and that transmits rotation to the spindle from the drive gear and cuts off the rotation transmission. space which is surrounded by a bearing member for supporting the spindle and said spindle and said housing, said is constantly atmosphere and communicating via the communication means provided on the spindle, the axial movement of the spindle
A fastening tool with a silent clutch, characterized in that it is configured to suck and exhaust .