CN107009179A - A kind of mechanical self-expanding High-speed Tool Shank - Google Patents

Abstract

A mechanical self-expanding high-speed tool holder. The cone of the tool holder is a hollow short cone with a taper of 1:10. There is an axial strip-shaped through hole on the cone. The flange connected as a whole has a screw hole on it, and it is connected with the chuck through fastening screws. Corresponding to the outer diameter of the short shaft, the short shaft of the mandrel placed in the cone is provided with two round platforms vertically connected to the short shaft, and the outer peripheral surfaces of the two round tables are part of the cone with an axial strip-shaped through hole The inner taper surface corresponds to the taper surface. The short axis of the mandrel is set at the end of the cone tail end. The axial inner screw hole is a standard rivet hole for connecting the rivet. Disc springs sleeved on short shafts are arranged between them. The invention has a simple structure, is easy to realize the dynamic compensation of the centrifugal expansion of the main shaft and the tool handle, and can significantly increase the limit speed.

Description

A mechanical self-expanding high-speed tool holder

FIELD OF THE INVENTION The present invention relates to machining tools, in particular tools for high speed cutting.

BACKGROUND OF THE INVENTION High-speed machining has been widely used in machining due to its advantages of high efficiency, high precision and high surface quality. The high-speed tool system is a connection system composed of a spindle, a tool holder, a collet, a tool and a clamping mechanism, and the tool holder is a key component connecting the spindle and the tool. High-speed machining puts forward strict requirements on the positioning accuracy and connection stiffness of the high-speed toolholder/spindle interface. The biggest problem in the tool holder/spindle interface at high speed is that the high-speed centrifugal expansion of the tool holder and the spindle does not match, that is, the centrifugal expansion of the spindle is greater than the centrifugal expansion of the tool holder, which affects the limit speed of the tool holder/spindle interface (tool holder and spindle) The highest speed at which the spindle maintains good positioning accuracy), positioning accuracy and coupling rigidity. Aiming at the problem of centrifugal expansion of the high-speed spindle/tool holder interface, domestic and foreign solutions include: (1) increasing the fit interference of the spindle/tool holder to compensate for the centrifugal expansion difference between the two. (2) Increase the centrifugal expansion of the handle. It adopts a hollow handle and uses an expanding claw broach mechanism to help it expand, such as an HSK handle. (3) Reduce the expansion of the spindle.

In order to solve the problem of high-speed centrifugal expansion, Germany, the United States, Japan and other countries have successively developed several kinds of high-speed tool holders. One is a replacement high-speed tool holder with a taper of 1:10, such as HSK from Germany, KM from the United States, and CAPTO from Sweden; the other is an improved version of the traditional BT tool holder with a taper of 7:24. , such as Japan Big-Plus, NC5, 3Lock, WSU, AHO, etc. Among them, HSK is the most representative high-speed tool holder. The structural features of the HSK tool holder are: hollow, thin-walled, short taper, taper 1:10; the end face and the taper face are positioned and clamped at the same time; the external expansion clamping mechanism is used from the inside to the outside. Although the HSK tool holder has greatly increased the limit speed of the spindle, there are still some problems: (1) The limit speed is still low, which cannot meet the higher speed requirements; (2) The local asymmetric structure leads to poor dynamic performance; (3) The external expansion clamping mechanism makes the contact of the taper surface uneven, resulting in serious local wear of the taper shank.

SUMMARY OF THE INVENTION The object of the present invention is to provide a mechanical self-expanding high-speed tool holder with simple structure, easy to realize dynamic compensation of the centrifugal expansion of the main shaft and the tool holder, and the limit speed can be significantly increased.

Technical scheme of the present invention is specifically as follows:

The invention mainly includes: a cone, a mandrel and a disk spring. The cone of the handle is a hollow short cone with a taper of 1:10. There are axial strip-shaped through holes on the cone, preferably 6-12 axial strip-shaped through holes evenly distributed for Improve radial flexibility, the specific number is determined according to the specification of the tool holder. A flange connected to the outer conical surface of the head end of the cone (that is, the large opening end) is provided, and a screw hole is provided on the flange, which is connected with the collet through fastening screws. The tail end (i.e. the small opening end) of the cone is provided with an annulus connected to it in an inner cone, and its central through hole diameter corresponds to the minor shaft outer diameter of the mandrel, so that the minor shaft can be inserted in the central through hole. The short axis of the mandrel placed in the cone is provided with two circular platforms vertically connected to the short axis, and the outer peripheral surfaces of the two circular platforms are corresponding to the inner tapered surface of the axial strip-shaped through hole part of the cone. tapered surface. The length of the minor axis of the mandrel is less than or equal to the length of the tool handle taper. The end of the short axis of the mandrel facing the tail end of the cone is provided with an axial inner screw hole, which is a standard rivet hole for connecting the rivet. Between the tail end of the cone and the round platform of the mandrel, there is a disc spring that is sleeved on the short shaft, and its function is to reduce shock and reset the mandrel when the handle is removed.

Compared with the prior art, the present invention has the following advantages:

1. It can dynamically compensate the centrifugal expansion of the tool holder and the spindle, and increase the limit speed of the tool holder/spindle interface. Compatible with existing 1:10 taper high-speed toolholders, the structure is simple and easy to implement.

2. The present invention has a hollow structure, which reduces the mass of the tool handle and can realize quick tool change.

3. The disc spring has a damping effect on the spindle-tool holder system, which improves the dynamic performance of the tool holder.

Description of drawings

Fig. 1 is a schematic cross-sectional front view of the present invention in use.

Fig. 2 is a schematic diagram of the axial side of the present invention.

Fig. 3 is an axial schematic view of the tool holder cone of the present invention.

Fig. 4 is a schematic axial view of the mandrel of the present invention.

Among them: 1. Collet; 2. Screw; 3. Cone; 4. Disc spring; 5. Mandrel; 6. Pull nail; 7. Screw hole; 8. Axial strip-shaped through hole; 9. Inner cone 10. Outer cone surface; 11. Round table A, 12. Round table B; 13. Pull nail hole.

detailed description

In the schematic diagram of the mechanical self-expanding high-speed tool holder shown in Figure 1 and Figure 2, the cone 3 of the tool holder is a hollow short cone with a taper of 1:10, and 8 uniformly distributed Axial strip-shaped through holes 8 are shown in FIG. 3 . A flange connected to the outer conical surface 10 of the head end of the cone (that is, the large opening end) is provided, and the flange is provided with a screw hole 7, which is connected to the collet 1 through the fastening screw 2. The inner cone surface 9 of the tail end (ie the small opening end) of the cone is provided with an annulus connected with it, and the diameter of the central through hole corresponds to the minor axis outer diameter of the mandrel 5 . The short axis of the mandrel placed in the cone is provided with two circular frustums A11 and B12 vertically connected to the short axis, and the outer peripheral surfaces of the two circular frustums are all inner cones with the cone body having an axial strip-shaped through hole. The corresponding cone face. The length of the minor axis of the mandrel is less than or equal to the length of the tool handle taper. The end of the short axis of the mandrel facing the tail end of the cone is provided with an axial inner screw hole, which is a standard rivet hole 13 for connecting the rivet 6, as shown in FIG. 4 . A disc spring 4 sleeved on the short shaft is provided between the tail end of the cone and the mandrel truss.

Working process and principle of action of the present invention are roughly as follows:

When the handle is loaded, the broaching mechanism of the machine tool (installed in the spindle hole) tightens the handle through the pull stud 6 to realize double-sided contact between the outer tapered surface 10 and the end face. After the knife handle is tightened, the broaching force F (the axial force acting on the pull nail 6) is equal to the elastic force of the disc spring 4 and the axial force (knife The sum of the axial force of the inner cone surface 9 of the shank cone on the mandrel 5), this resultant force is transformed into the pressure of the cone surface and the end surface of the tool shank to make the tool shank and the main shaft reliably connected. When the main shaft rotates at high speed, the centrifugal expansion of the tool holder cone 3 is smaller than the centrifugal expansion of the main shaft taper hole, and the contact stress of the mating surface is reduced or even a gap appears. The acting force of the inner cone surface 9 of the shank cone on the mandrel 5) decreases, and the force balance of the mandrel 5 is destroyed. The broaching force F causes the mandrel 5 to produce a small amount of axial displacement through the pull nail 6, and increases the pressure between the conical surfaces of the two circular platforms 11 and 12 on the mandrel and the inner conical surface 9 of the handle cone 3, so that the outside of the handle The radial deformation of the conical surface 10 compensates the centrifugal expansion difference between the main shaft and the tool holder cone 3, maintains a reasonable conical surface matching contact stress, and increases the limit speed.

Claims (3)

1. A mechanical self-expanding high-speed tool holder, characterized in that: the cone of the tool holder is a hollow short cone with a taper of 1:10, and an axial strip-shaped through hole is arranged on the cone, and the cone first The outer conical surface of the end is provided with a flange connected with it, and there is a screw hole on it, which is connected with the chuck through fastening screws. The inner conical surface of the tail end of the cone is provided with a ring connected with it. The diameter of the mandrel corresponds to the outer diameter of the short axis of the mandrel. The short axis of the mandrel placed in the cone is provided with two circular platforms connected vertically to the short axis, and the outer peripheral surfaces of the two circular platforms are arranged on the axis of the cone. To the tapered surface corresponding to the inner tapered surface of the strip-shaped through hole part, the short axis of the mandrel is provided with an axial inner screw hole at the end of the cone tail end, which is a standard rivet hole for connecting the rivet. A disc spring sleeved on the short shaft is arranged between the tail end and the round table of the mandrel. 2. The mechanical self-expanding high-speed tool holder according to claim 1, characterized in that: 6-12 uniformly distributed axial strip-shaped through holes are arranged on the cone. 3. The mechanical self-expanding high-speed tool holder according to claim 1 or 2, characterized in that: the length of the short axis of the mandrel ≤ the length of the tool holder cone.