Design of main parts of spring collet

Collet sleeve
The clamping organization of the Spring Collet selects the spiral clamping organization to finish clamping and lock the tool handle. The nut sleeve is equipped with a gear ring, which is intended to transmit torque through the correct meshing of the gear ring and the gear in the clamping organization. In order to reduce the collision and loss of the ring gear nut sleeve when clamping the tool, a V-shaped groove is added between the outer end of the ring gear nut sleeve and the retainer ring of the spring sleeve, in which a circle of steel balls are closely arranged, thus forming the simplest structural plan of the spring collet. In order to further enhance the impact resistance of the spiral clamping structure in the cutting process (that is, the self-locking clamping function of the structure can still be maintained during the impact process), the structural form of the spring collet clamping structure can completely choose the structural form of a powerful spring collet tool handle produced in China. It is concluded that the structure of the spindle shaft end has the characteristics of simplicity, good craftsmanship and small occupation space, which is conducive to the optimization and standardized planning of the spindle of the dry machine tool according to its own requirements.

Main shaft end structure
The two semicircle keys placed at the bottom of the hole are used to transmit the satisfied cutting torque to the cutting edge of the tool through the tool shank. The guide cone is machined at the top of the semicircle key to facilitate the stabbing of the tool handle. The same of two semicircle keys
The side (non operating side) is processed along the axial direction and fixed in the groove. The operating surface is slightly higher than the appearance of the semicircle key. Its function is to eliminate the semicircle key and the semicircle slot operation after the two semicircle keys penetrate into the semicircle slot at the end of the tool handle

The surface clearance prevents the tool cylindrical shank from being scratched due to the relative sliding when the cutting torque is greater than the conflicting torque between the spring sleeve and the tool shank due to the existence of the clearance after the tool stabbing. An air jet is arranged at the center of the bottom of the main shaft hole, and the air jet is connected with the air path of the main shaft center hole. When exchanging tools, compressed air passes through the air jet and enters the spring sleeve cavity to blow away the iron filings and dirt attached to the spring sleeve and the tool handle. The cone angle 2a of the inner cone is generally 30 °. The intention of taking a larger taper angle is that the tool handle is easy to be loosened, which is convenient for tool loading and unloading. In order to ensure that there is no relative movement between the tool handle and the spring sleeve in the process of clamping the tool, that is, the tool and the spring sleeve make synchronous axial displacement together, and also ensure that the tool can maintain good axial repeated positioning accuracy after each tool change, it is necessary to ensure that the positioning end face of the tool handle and the positioning end face of the spring sleeve keep touching during the clamping process. In this plan, this action is controlled by the tool exchange position

Provided by the manipulator, that is, the manipulator always supplies the tool handle with an upward elastic force that makes the positioning end face of the tool handle flange close to the end face of the spring sleeve during the clamping process. Now the centering accuracy of the elastic chuck can generally reach 0.01 mm or even higher. In a pair of screw pairs, when the equivalent collision angle f0 of the spiral rising angle small dry thread, the screw clamping organization will have a good self-locking function. For the general specification thread, the steel-steel conflict pair is selected, and its equivalent conflict angle o0=6 ° 35 ', while the spiral rise angle of this thread is 2 ° 29', that is, ≤ 00

Spring collet
To improve the operation function of the machine tool spindle and satisfy the requirements for active tool change of CNC machine tools, it is necessary to plan and develop the spring collet at the spindle end of the machine tool spindle, which can well solve the following key problems:

1: There should be sufficient touch stiffness between the cylindrical tool handle and the contact surface of the spring collet in the clamping state. The contact stiffness between the spring sleeve in the spring collet and the contact surface of the taper hole at the spindle end of the machine tool should also be satisfied under the clamping state.

2: During the machining process, it is necessary for the machine tool spindle to feed the tool and transmit full cutting torque.

3: The strong-spring collet adopts the spiral clamping organization. In addition to opening the clamping knife and supplying large radial clamping force, it is also necessary to have reliable self-locking function.

4; After replacing the tool each time, the tool AC mounting and spring collet should have a high turning and positioning accuracy.

5; In the process of tool change, it has the function of actively cleaning the iron dust and slag in the tool handle and spring collet cavity.

6: The spindle end of the machine tool should have simple structure and good processability, which is convenient for the optimization planning of the spindle itself.

Ring gear nut sleeve
The spring sleeve is a thin-walled conical elastic element, which is the key part of the spring collet. The taper part of the spring sleeve can be provided with multiple axial grooves as required. The large diameter end of the spring sleeve is planned with a stop ring to provide axial thrust to the spring sleeve through the stop ring.