JPS58155136A - Tool holder mounting device - Google Patents

Abstract

PURPOSE:To miniaturize the titled device together with an increae of its rigidity and to improve its operation efficiency, by so constituting that attachment and detachment of a tool holder can be made practicable by nearly one-action operation. CONSTITUTION:A tool holder insertion hole 10b is bored inward in an axial direction from the tip 10a of a main spindle 10 and key grooves 10c are formed at two places on the tip 10a, in a tool holder installing device which installs a tool holder holding a thread cutting tool, such as a tap to a main spindle of a machine tool. A leaf spring 13 is provided in a circumferential groove 11a along its circumference and two steel balls 12 are pressed into an insertion hole 11e always by the leaf spring 13. Then, the tool holder possesses a holder shunk which enters into the insertion hole 10b of the main spindle 10, and a shaft part connecting with a sleeve 11 is formed at a place far ahead of a reference plane meeting at right angles with an axial direction of its end. With this constitution, simultaneously with an increase of rigidity the titled device is miniaturized and its operation efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tool holder mounting device for mounting a tool holder holding a thread cutting tool such as a tap to the main shaft of a machine tool.

BACKGROUND ART Conventionally, a device as shown in FIG. 1 has been generally used to attach a tool holder to a main shaft of a machine tool, particularly a multi-spindle machine. That is, a tool holder insertion hole 1a is bored in the tip of the main shaft 1 in the axial direction, and a keyway 1 is inserted along the insertion hole 1a.
b is engraved, and a screw hole IC that penetrates in the radial direction is formed at a certain distance from the tip surface of this main shaft 1.
A tool holder 3 with a key 2 attached to its outer diameter is inserted into the insertion hole 1a, and the tool holder 3 is fixed in the direction of rotation around the axis by the cooperation of the key 2 and the keyway 1b. The tool holder 3 is fixed in the axial direction by a screw 4 screwed into the hole IC. In addition, T is a tool, and tool holder 3
The collet 5 is inserted into the tool mounting hole 3a via a collet 5, and the collet 5 is pushed into the tool mounting hole 3a by a lock nut 6.

However, this conventional device has the following drawbacks. That is, (1) among the operations for attaching the tool holder 3 to the main shaft 1, for example, aligning the key 2 with the key groove 1b or tightening the screw 4 is troublesome and time-consuming. (2
) Since the keyway 1b is provided in the main spindle 1, the diameter of the main spindle 1 itself becomes large, and the distance between adjacent main spindles also increases, making it difficult to drill holes with small pitch intervals. On the other hand, since the stepped portion of the tool holder 3 comes into contact with the tip end surface of the spindle 1, the influence of vibrations on the tool T is relatively small, and the tool T has the advantage of being made rigid.

In order to eliminate the above-mentioned drawbacks, the present applicant first filed a patent application in 1973.
No. 5-188737 proposed a tool holder mounting device in which the insertion depth of the tool holder into the main shaft is regulated by the position of a flange provided on the outer periphery of the tool holder.

An object of the present invention is to improve the prior application and provide a tool holder mounting device that increases rigidity and is downsized. In an apparatus having an axial connection means for connecting the spindle and the tool holder through cooperation between the bottom of the insertion hole and the shaft portion at the tip of the tool holder, and a means for transmitting torque from the spindle to the tool holder, the connection means is A steel ball placed at the bottom of the spindle is elastically pressed by a spring force to connect the steel ball in the axial direction to an inclined surface formed on the shaft of the tool holder and whose diameter increases toward the tip of the shaft, and The axial position is regulated by contact between the reference surface provided at the base of the shaft portion and the reference surface near the bottom of the insertion hole of the spindle, and the torque transmission means is provided by a protrusion provided at the tip of the spindle and the outer periphery of the tool holder. It is characterized by being connected in the rotational direction via a key.

The present invention will be explained in detail based on the embodiments shown in FIG. 2 and below.

2 is a longitudinal cross-sectional view of the main shaft 10, and FIG. 3 is an enlarged cross-sectional view taken along the line G in FIG.
A tool holder insertion hole tab is drilled in the axial direction from 0a to the back, and keyways 1. Oc is formed. Further, a bottomed cylindrical sleeve 11 is inserted into the bottom of the insertion hole 10b, and this sleeve 11 has a large diameter hole 11a that opens toward the tip, and a hole axially bored in the bottom 11b. It has a small diameter hole 11c, and a circumferential groove 11d is formed in the circumferential direction on the outer peripheral surface. This circumferential groove lid has two steel ball insertion holes facing each other in the radial direction.
are bored, and steel balls 12 are inserted into each of the insertion holes lie. The insertion hole lie is tapered so that the diameter becomes smaller toward the inside, and the diameter of the insertion hole lie facing the large diameter hole 11a is smaller than the diameter of the steel ball 12, so that the steel ball 12 cannot be pulled out into the large diameter hole 11a. It is designed not to come out.

A leaf spring 13 is provided around the circumferential groove lid, and the two steel balls 12 are constantly pressed into the insertion hole lie by the leaf spring 13. In addition, the insertion hole 10 of the leaf spring 13 and the main shaft 10
There is a slight gap between the tool T and the tool T, so that the backlash caused by the tool T can be absorbed. Further, a port 14 is inserted through a small diameter hole lie in the bottom portion 11b of the sleeve 11, and the sleeve 11 is fixed to the main shaft 10 in the axial direction via a spacer 15. Bottom part 11 of sleeve ll
A bottle 16 is inserted between the hole tab b and the bottom of the insertion hole tab to prevent the sleeve 11 from rotating around the port 14. Note that 17 indicates a rotation stopper pin for the leaf spring 13.

FIG. 4 is a partially sectional side view of the tool holder 20 inserted into the insertion hole 10b of the main spindle 10, and FIG. 5 is a sectional view taken along line v-V in FIG. be. The tool holder 20 has a holder shank 21 that fits into the insertion hole 10b of the main spindle 10, and a reference surface 21a at the end of the holder shank 21, which is orthogonal to the axial direction, has a reference surface 21a at the further end of which is inserted into the insertion hole tab of the main spindle 10. Sleeve 11 located at the bottom
A shaft portion 21b is formed to be connected to the shaft portion 21b. This shaft part 21
b is formed to fit into the large diameter hole 11a of the sleeve 11, and has a V-groove 2 having a sloped portion in the middle of the shaft portion 21b.
1c is provided around the periphery, and further provided are face-shaving portions 21d which are parallelly shaved from both sides of the shaft portion 21b. ■The axial distance between the bottom of the groove 21c and the reference surface 21a (L2 in FIG. 4) is longer than Ll in FIG. It is slightly shorter, and the dimensions of the face cut part (M+ in Fig. 5)
is formed to be smaller than M2 in FIG. 3, that is, the dimension between the steel balls 12. Further, in the tool holding section 20a provided at the other end of the tool holder 20, the holder shank 21 has a large diameter, and the collet holder 22
An insertion hole 21e for inserting is bored in the axial direction.

The tip of the collet holder 22 has a small diameter, and the rear end has a large diameter, and a thread groove 22a is carved around the rear end so that it is screwed into the inner thread of the nut 23. .

This nut 23 has a steel ball 24 attached to the end of the holder shank 21.
Alternatively, it is rotatably attached via a wire ring, and the positional relationship with the collet holder 22 can be fixed with a set screw 25. Further, a collet 26 for fixing a tool T such as a tap is inserted into a tapered hole 22c that is bored inward from the end 22b of the collet holder 22 and becomes smaller in diameter as it progresses inside.

The outside of the collet 26 is formed into a tapered shape to match the tapered hole 22c, and a split groove 26a is provided in the axial direction to obtain elasticity, and a threaded groove is formed on the outer periphery of the large diameter side of the collet 26. 26b is engraved. A lock nut 28 is rotatably attached to the outer peripheral surface of the end 22b of the collet holder 22 via a steel ball 27, and a screw carved on the inner periphery of the outer end of the lock nut 28 is inserted into the thread groove 26b of the collet 26. By the rotation of the lock nut 28, the collet 26 can be freely inserted into and removed from the tapered hole 22c. Further, around the boundary between the small diameter part and the large diameter part of the holder shank 21, a substantially cylindrical drive collar 29 slides in the axial direction via a compression spring 30 between it and the large diameter part of the holder shank 21. It is movable around the perimeter. On the shaft portion 21b side of the drive collar 29, protruding keys 29a are formed at two positions on the circumference so as to protrude in the axial direction as shown in FIG. Then, a tool holder 20 is attached to the spindle lO.
When the tool T is inserted and the two are connected, the protruding key 29a engages with the keyway 10c on the tip surface 10a of the main shaft 10, so that the cutting force to the tool T can be transmitted from the main shaft IO. Further, a pin 31 is inserted through the drive collar 29, holder shank 21, and collet holder 22 so that torque can be transmitted without rotating these separately. The end of the tool T has a prismatic shape and is fitted into a receiving part 22d of the same shape at the bottom of the tapered hole 22c of the collet holder 22, and the tool T itself cannot be rotated with respect to the tool holder 20. It has become.

Next, how to use this embodiment of the above-described configuration will be explained. It is assumed that, prior to use, the tool holder 20 consisting of the holder shank 21, collet holder 22, lock nut 28 and drive collar 29 has already been assembled as one piece. Therefore, in order to secure the tool T to the tool holder 20, first rotate the lock nut 28 to loosen it, and then attach the tool T together with the collet 26 to the collet holder 20.
2 into the taper hole 22c, fit the end of the tool T into the receiving part 22d at the bottom of the taper hole 22c, and then tighten the lock nut 28.
Rotate the collet 26 in the opposite direction to the tapered hole 22.
The tool T is fixed by feeding it into the hole c. The tool holder 20 with the tool T fixed in this way is placed on the spindle 10.
To attach the tool to the sleeve 11, hold the tool holding portion 20a and insert the holder shank 21 into the insertion hole tob of the main shaft IO until the shaft portion 21b of the holder shank 21 abuts against the sleeve 11. Then, when the tool holder 20 is pushed in and rotated about the shaft in either the left or right direction, the shaft portion 21
The M1 part of the face-shaving part 21d of b and the steel ball 1 of the sleeve 11
Since the positions of the M2 portions between the holder shank 21 and the holder shank 2 coincide with each other, if the holder shank 21 is pushed in while resisting the elastic force of the compression spring 30, the reference surface 21a of the holder shank 21 comes into contact with the end surface 11f of the sleeve 11, preventing it from entering in the axial direction. Ru. At this stage, the steel balls 12 of the spindle 10 are in engagement with the V-groove 21c of the shaft portion 21b, and the tool holder 20 can rotate relative to the spindle 10, so the tool holder 20a is pressed toward the spindle lO side. When the drive collar 29 is rotated approximately 90 degrees, the protruding key 29a of the drive collar 29 will move to the main shaft lO.
The two fit into the key groove 10C, and the two engage while being pushed by the compression spring 30. At this time, at the back of the insertion hole 10b, the distance L1 between the bottom of the V-groove 21c and the reference surface 21a is slightly smaller than the distance L2 between the center of the steel ball 12 and the end surface 11f of the sleeve 11. Therefore, steel ball 12
The elastic force of the plate spring 13 presses the slope portion on the back side of the groove 21c, and as shown in FIG. 7, the tool holder 20 is pulled into the interior and fixed in the axial direction.

When removing the tool holder 20 from the spindle lO, move the drive collar 29 against the elastic force of the compression spring 30,
After disengaging the protruding key 29a from the keyway 10c of the main shaft 10, rotate the tool holder 20 by 90 degrees to remove the shaft portion 21b.
If the steel ball 12 is disengaged from the V-groove 21c, it can be pulled out as is.

During use, rotational force is transmitted from the spindle lO to the tool holder 20, and machining is performed by the tool T. However, if there is a difference between the pitch of the tool T and the machine tool's opening pitch, accurate machining may not be possible. Can not.

Therefore, a puff crush absorption mechanism is required to absorb the difference in pitch between the two and perform accurate thread cutting.
In this embodiment, since the leaf spring 13 has room to expand outward, the steel ball 12 can move outward and absorb backlash.

Sleeve 11 of main spindle 10 and shaft portion 21a of tool holder 20
In order to establish both the axial connection means between the main shaft 10 and the rotational direction connection means between the distal end surface 10a of the main spindle 10 and the outer peripheral part of the tool holder 20, in the embodiment, it is necessary to
It is necessary that the engagement rotation angle of d and the engagement rotation angle of the keyway 10c of the distal end surface 10a and the protruding key 29a of the drive collar 29 are different, and it is desirable that the angles differ by 90 degrees.

As described above, the tool holder mounting device according to the present invention allows attachment and detachment of the tool holder to be extremely easy compared to conventional devices of this type, and can be performed with almost a one-touch operation, which can be expected to improve work efficiency. Since the axial connection position is performed near the tip of the insertion portion of the tool holder, the axial length is shortened and the rigidity is increased. Furthermore, since it is equipped with a backlash absorption mechanism, accurate thread cutting can be performed.

Furthermore, since the transmission of one-rotation torque is done from the tip of the spindle to the drive collar on the outer periphery of the tool holder, there is no need to provide a key for transmitting rotational torque inside the shaft of the spindle. This makes it possible to reduce the diameter of the tube, thereby reducing costs.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing a conventional example of a tool holder mounting device;
Fig. 2 and subsequent figures show an embodiment of the tool holder mounting device according to the present invention, in which Fig. 2 is a longitudinal sectional view of the main shaft, Fig. 3 is an enlarged sectional view taken along the line m-m, and Fig. 3 is an enlarged sectional view of the main shaft. Figure 4 is a partial vertical sectional view of the tool holder, Figure 5 is an enlarged sectional view taken along line ■-V in Figure 4, Figure 6 is an enlarged perspective view of a portion of the drive collar of the tool holder, and Figure 7 is the main shaft. FIG. 3 is a partial vertical cross-sectional view showing the mounted state of the tool holder. 10 is the main shaft, 10a is the tip, lOb is the tool holder insertion hole, lOc is the keyway, 11 is the sleeve, llf is the end surface, 12 is the steel ball, 13 is the leaf spring, 20 is the tool holder, 2
0a is a tool holding part, 21 is a holder shank, 21a is a reference surface, 21b is a shaft part, 21c is a groove, 21d is a face cutting part, 23 is a nut, 26 is a collet, 28 is a lock nut, 29 is a drive collar, 29a is a protruding key, and 30 is a compression spring. Patent applicant Kuroda Seiko Co., Ltd. Toyota Motor Corporation

Claims (1)

[Claims] 1. Insert the tool holder into the tool holder insertion hole of the spindle, and by the cooperation of the bottom of the insertion hole of the spindle and the shaft at the tip of the tool holder, there is an axial connection means between the spindle and the tool holder, and there is a connection from the spindle to the tool holder. In a device having a means for transmitting torque to a tool holder, the connecting means includes a steel ball disposed at the bottom of the main shaft that is attached to a slope portion formed on the shaft of the tool holder and whose diameter increases toward the tip of the shaft. The torque transmitting means is connected in the axial direction by being elastically pressed by force, and the axial position is regulated by contact between the reference surface provided at the base of the shaft portion and the reference surface near the bottom of the insertion hole of the main shaft. The tool holder mounting device is characterized in that the tip of the spindle is connected in the rotational direction via a protruding key provided on the outer periphery of the tool holder.