JPH0236015A - Tool holding apparatus - Google Patents

Abstract

PURPOSE:To avoid clutch cutting during the upholding of a tool by locating a flange of a periphery of a coupled driving shaft at a front side of a driving ring in which a clutch groove is formed, and a clutch ball holding hole being formed in the flange, by slanting the holding groove so that it goes in a direction of normal rotation of a tool as it is forwarded. CONSTITUTION:A driving ring 6 of a tap collet 2 being rotated synchronously with atool body 1, a coupled driving shaft 4 is engaged in an inner circumference of the driving ring 6, while a ring flange 24 which overhangs a periphery in a radial direction and is located in a front side of the driving ring 6 is formed by unification. In the flange 24, a plurality of a holding hole 16 of a clutch ball 8 of a radial direction is formed, and the ball 8 is energized to a clutch groove 17 of a front side of the driving ring 6 through a spring 9. The holding hole 16 is so slanted as it goes in a reverse rotational direction as it is forwarded to the side of the driving ring 6. When the larger load than a torque set in normal rotation is applied, the ball 8 is detached from the clutch groove 17 for the clutch cutting condition. During the reverse rotation in the upholding of the tool, the ball is constantly turned on through the cam actuation of the holding hole 16.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention primarily relates to a tool holder for holding a tap.

(Prior art) Various types of tap holders equipped with safe torque (safety device) type clutch mechanisms have been developed, and these clutch mechanisms have a maximum clutch transmission torque value that depends on the size of the tap and the cutting torque. It is set. Furthermore, the clutch mechanism of the conventional tap holder is designed to disengage the clutch in response to the occurrence of abnormal torque, whether during forward rotation or reverse rotation. That is, in thread cutting work, after forward rotation (forward rotation) for thread cutting, it is necessary to rotate the tap in the opposite direction to remove the tap from the screw hole, but the clutch is designed to disengage when abnormal torque is generated during any rotation. In addition, there are some devices that provide a slight difference between the set values for forward rotation and reverse rotation.

However, as can be seen when considering the case of thread cutting a bottom hole, the clutch disengagement action is extremely effectively utilized during forward rotation while thread cutting, but the clutch disengagement action is rarely utilized during extraction rotation. In fact, there is a concern that the clutch may disengage unnecessarily, reducing the efficiency of the extraction work.

In addition, as a conventional example, there is a tool holder known in Japanese Patent Publication No. 5748331 in which the clutch is activated only during forward rotation, but an inclined notch for holding the ball is formed on the driving member side, and a clutch is formed on the driven member side. forming a groove.

(Object of the invention) The object of the invention is, for example, when performing thread cutting work,
When abnormal torque occurs during forward rotation for thread cutting, the rotation of the tap is ensured to ensure safety, and during reverse rotation for extraction, the tap can be pulled out from the screw hole reliably and smoothly, improving work efficiency. The objective is to further improve the holding strength of the clutch ball.

(Technical Means for Achieving Objective 1) In order to achieve the above objective, the present invention forms an outward flange 24 on the outer peripheral surface of the driven shaft 4 as a clutch mechanism.
4 is located on the front surface of the drive ring 6, a plurality of clutch ball holding holes 16 are formed in the flange 24 at intervals in the circumferential direction, and the clutch ball 8 is inserted into the holding hole 16 in a longitudinally protruding manner. A clutch groove 17 is formed on the front surface of the ring 6 , and the clutch ball 8 is engaged with the rear clutch groove 17 by the clutch spring 9 via an annular plate 26 arranged on the front surface of the clutch ball 8 . As you move forward, the tool is tilted toward the forward rotation direction of the tool. During forward rotation, the clutch remains engaged when the cutting torque is within the set value, and when it exceeds the set value, the clutch is disengaged, and when the cutting torque is reversed, the clutch remains engaged. This prevents any cutting action from occurring.

(Example) The present invention will be explained below based on the drawings.

In Fig. 1, the tap holder consists of a holder main body 1 (imaginary line) and a tap collet 2, and the handle (not shown) on the rear end side (opposite the arrow F side) of the main body 1 is used to rotate the machine tool. Connect to the main shaft. The tap collet 2 includes a driven shaft 4, a lock bolt 23, etc., and also incorporates a one-way rotational clutch mechanism consisting of a drive ring 6, an annular plate 26, a clutch ball 8, a clutch spring 9, etc.

The drive ring 6 has its backward protrusion 6a engaged with the recess 1a of the main body 1, so that it always rotates integrally with the main body 1.
The driven shaft 4 is fitted into the inner periphery of the drive ring 6. The driven shaft 4 is integrally formed with an annular flange 24 that protrudes outward and outward from the radius. 16 are formed. A latch 17 that can freely engage with the clutch ball 8 is formed on the front surface of the drive ring 6.
Further, the clutch ball 8 is biased rearward by a clutch spring 9 via an annular plate 26.

As shown in FIG. 2, the holding hole 16 is inclined toward the forward rotation direction.

That is, it is inclined toward the reverse rotation B direction as it goes toward the drive ring 6 side.

The setting value of the clutch maximum transmission torque is determined by adjusting the amount of compression of the clutch spring 9 using the adjustment nut 10, but it is taken into consideration that a forward force is applied to the clutch ball 8 due to the cam action of the ball holding hole 16 during forward rotation. , and set the clutch spring 9 to a value that can sufficiently secure the necessary transmission torque during forward rotation for thread cutting.

When threading a hole in the bottom, during forward forward rotation of the thread (rotating in the direction of arrow A), the clutch ball 8 is urged backward by the elastic force of the clutch spring 9, and the meshing state with the clutch groove 17 is maintained. keep.

When the bottom of the hole is reached and a large load is applied to the tap T, the drive ring 6 is tilted in the direction of the arrow AJi with respect to the driven shaft 4, and the T! The clutch ball 8 is pushed forward by the cam action of the J hole 16, and the clutch is disengaged.

If a load exceeding the set torque is applied during forward rotation, ball 8
comes off from the clutch groove 17 and the clutch becomes disengaged, but
Since the driving ring 6 rotates (idling) with respect to the ball 8 and the driven shaft 4 while constantly contacting the ball 8, each time the clutch groove 17 passes the ball 8 portion, the ball 8 moves into the clutch groove by the action of the spring 9. 17, a sound is generated. In other words, while the drive ring 6 is idling, a rattling sound is continuously generated, and this sound alerts the operator to an abnormal condition in which the clutch is disengaged due to overload.

When extracting is rotated in the reverse direction (rotating in the direction of arrow B), the cam action of the holding hole 16 acts to push the ball 8 backward, so the clutch is always kept in the engaged state and the extracting operation can be performed reliably. .

As explained above, the present invention has the following advantages.

(1) An inclined clutch ball holding hole] 6 is formed in the flange 24 of the driven shaft 4, a clutch groove 17 that engages with the clutch ball 8 is formed in the drive ring 6, and a ball holding hole into which the clutch ball 8 is inserted. 16 is tilted toward the forward rotation direction as it goes forward, so that the cutting torque remains in the clutch engagement state within the set value during forward rotation, and becomes clutch disengaged when it exceeds the set value. Therefore, when threading a bottom hole with a tap T attached, by setting the forward rotation direction to be the forward and simultaneous rotation direction of thread cutting, the clutch will be reliably disengaged when reaching the bottom of the water or when abnormal torque is generated, resulting in a safe operation. It is possible to ensure sufficient sex.

In addition, at that time, the drive ring 6 idles relative to the driven shaft 4, and the clutch balls 8 intermittently contact the clutch groove 17, causing a "rattling" warning sound, and the work δ is overloaded. etc. can be confirmed.

(2) By slanting the holding hole 16, no clutch disengagement occurs during reverse rotation, so there is no need to worry about the clutch being unnecessarily disengaged during extraction work due to reverse rotation, improving work efficiency.

(3) Forming an outward flange 24 on the driven shaft 4, disposing the flange 24 on the front side of the drive ring 6, forming a clutch groove 17 on the front surface of the drive ring 6, and forming a ball holding hole in the flange 24. Since the clutch ball 8 is held in the driven shaft 16, it is not necessary to form a holding hole directly on the outer circumferential surface of the driven shaft 4 or to form a ball holding hole directly, so that the strength and rigidity of the driven wheel itself can be maintained.

(4) Forming an outward flange 24 on the driven shaft 4, disposing the flange 24 on the front side of the drive ring 6, forming a clutch groove 17 on the front surface of the drive ring 6, and forming a ball holding hole in the flange 24. 16 to hold the clutch ball, clutch spring 1
Since each clutch ball 8 is pressed through one annular plate by 0, the clutch ball holding structure is simple, and when assembling, there is a
The clutch ball 8, the annular plate 26, and the clutch spring 10 can be inserted sequentially from the front, and assembly is easy.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a tool holder to which the present invention is applied;
The figure is a sectional view taken along the line ■-■ in FIG. 8...Clutch ball, 9...Clutch spring, 16...Pol holding hole,
17...Clutch groove, 26...Annular plate Patent applicant: 11 Kenkosho Co., Ltd. Agent: Patent attorney Tadataka Kai (・)

Claims (1)

[Claims] A tool holder in which the driven shaft 4 is fitted onto the inner peripheral surface of the drive ring 6, a cutting tool is fixed to the driven shaft 4, and the drive ring 6 and the driven shaft 4 are connected via a clutch mechanism. As a clutch mechanism, an outward flange 24 is formed on the outer peripheral surface of the driven shaft 4, the flange 24 is positioned on the front surface of the drive ring 6, and clutch ball holding holes 16 are formed in the flange 24 at intervals in the circumferential direction. At the same time, a clutch ball 8 is inserted into the holding hole 16 so as to project forward and backward, a clutch groove 17 is formed on the front surface of the drive ring 6, and a clutch ball 8 is inserted through an annular plate 26 arranged on the front surface of the clutch ball 8. The clutch ball 8 is engaged with the rear clutch groove 17 by the clutch spring 9,
The shape of the holding hole 16 is sloped so that it comes to the forward rotation direction of the tool, and when the cutting torque is in the forward rotation, the clutch is kept in the engaged state when it is within the set value, and when it is greater than the set value, the clutch is disengaged. A tool holder characterized in that a clutch disengaging action does not occur during reverse rotation.