JPS6411425B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fixing device for a grinding wheel in a grinding spindle of a grinding machine with an automatic grinding wheel changer, which comprises a conical receptacle in the spindle head. and a grinding spindle with a clamping chuck actuated by a tension rod in the central bore and a receiving flange, the receiving flange consisting of a stationary flange part and a movable flange part, which A grinding wheel is received between a stationary flange part and a movable flange part, the stationary flange part being provided with a conical shape that fits into the conical receiving part on its side facing the spindle head. a receiving hole and a central clamping pin, the clamping head of which is adapted to co-operate with the clamping chuck, and the stationary flange portion on its opposite side from the spindle head. This invention relates to a type of grinding wheel changing device having an engaging member.

PRIOR ART In order to reduce installation and other time and to obtain completely automatic working operation in grinding machines, fastening devices are known for grinding machines of the type mentioned at the outset (German patent application (See specification of Publication No. 3246168). In this known fixation device,
The stationary flange part of the receiving member has a relatively long conical receiving hole, the axial length of which is equal to that of the conical receiving part [DIN (German Industrial Standard) 6375].
is larger than the maximum diameter of The spindle head is accordingly provided with a long conical receptacle.
At one end of the machine part used for clamping the workpiece, a swivelable magazine is provided, which has on each of its four sides one grinding wheel holding device with clamping chucks. are doing. This clamping chuck is adapted to engage an additional clamping head, which clamping head is adapted to engage on the side of the stationary flange opposite the spindle head. The machine table is moved towards the grinding spindle in two directions extending at right angles to each other. In this format,
In order to carry out a wheel change, the magazine can be positioned in front of the spindle head in such a way that the axis of the new wheel to be installed exactly coincides with the spindle axis. By moving the machine table in the direction of the spindle axis, the stationary receiving flange is inserted into a conical receiving part of the spindle head. By pulling on a tension rod located in the spindle, the clamping chuck closes around the clamping head of the clamping pin and fixes the grinding wheel in the correct position on the grinding spindle head. However, with this known fixing device, when changing the grinding wheel, it is necessary to precisely align the axis of the grinding wheel to be installed with the spindle axis, which requires that the magazine be placed on the machine table and Precise working provided is obtained by placing one of the wheel holding devices on the machine table. However, the magazine requires a relatively large amount of space on the machine table, so that the clamping surface of the machine table and the required working length must be correspondingly small. Moreover, for each grinding wheel, a relatively expensive grinding wheel holding device must be provided in the magazine, which works very precisely. The chuck arms commonly used in tool changers in milling machines cannot be used because they operate too inaccurately. Moreover, the relatively long dimensions of the conical receptacle are problematic because they are easily soiled. For this reason, in known grinding machines, a washing device is provided in the station of the magazine instead of a grinding wheel holding device. The cleaning device is moved into a position surrounding the conical receptacle to clean the conical receptacle before the grinding wheel is installed. However, this increases the time required to change the grinding wheel.

OBJECT OF THE INVENTION The object of the invention is to provide a fixing device for a grinding wheel in a grinding spindle of a grinding machine with an automatic grinding wheel changer of the type mentioned at the outset, which overcomes the drawbacks of the known devices. Avoid and, above all, allow the use of known flickering devices on milling machines for tool changes, reducing the risk of soiling the conical receptacle and preventing the conical receptacle from being exposed when changing the grinding wheel. The purpose is to eliminate time-consuming cleaning operations.

Means for Solving the Problem The present invention solves this problem, in which the conical receiving portion is configured as a short conical body having a radially extending annular flat surface continuous to its maximum diameter, and a stationary flange portion has an abutment surface abutting the flat surface; the spindle head has a cylindrical centering hole concentric to the conical receptacle; The pin has a conical guide part continuous with its clamping head, which conical guide part transitions into a centering cylinder which fits with a play in the centering hole, and the engagement member has a The centering cylinder is configured as an annular groove concentric with the stationary flange portion for engaging the chuck pawl of the grinding wheel changing device, and the centering cylinder is configured such that the conical receiving hole is conical when changing the grinding wheel. It extends in the direction towards the clamping head to such an extent that it engages in the centering hole before reaching the shape receiving part.

Operation Since the contact surface of the immovable flange part rests closely against the flat surface of the spindle head during the grinding operation, there is no risk of contamination of the flat surface or of the short conical part. Moreover, since the short conical shape has a relatively small surface, there is only a slight risk of contamination when changing the grinding wheel. For this reason, it is not necessary to clean the conical receptacle or the flat surface when changing the grinding wheel. This reduces the time required to replace the grinding wheel.

However, a particular advantage of the device according to the invention is that it can be used both as a grinding wheel changer and as a tool changer in a milling machine.

In order to engage the chuck pawl of the grinding wheel changer, the stationary flange part is provided with an annular groove corresponding to the chuck pawl. In short conical shapes, the difference between the maximum diameter of the conical receiving hole and the minimum diameter of the conical receiving hole is relatively small, so that the spindle must be removed before the wheel is fitted over the spindle head. For centering with respect to the axis, the precision of the guide provided by conventional chuck pawls is insufficient. For this reason, the clamping pin is provided with a conical guide and a centering cylinder. By moving the stationary flange part in the direction towards the spindle head, the conical guide part first reaches the centering hole provided in the spindle head. If the axis of the immovable flange does not match the axis of the spindle, the conical outer circumferential surface of the conical guide will abut the centering hole, and when the immovable flange is further moved toward the spindle head, the centering cylinder will not be centered. guided into the hole. The centering cylinder engages with some play in the centering bore, so that the centering cylinder precenters the stationary flange relative to the spindle head. The pre-centering obtained before the conical receiving holes reach the conical receiving portions is sufficient for the subsequent engagement of these conical receiving holes and the conical receiving portions with each other. The actual centering of the stationary flange part is achieved by the conical receptacle. This pre-centering avoids damage to the flat and conical receptacles that can occur when the axis of the stationary flange is not sufficiently aligned with the spindle axis and the abutment surface does not abut the end face of the spindle head. It will be done.

Embodiment Next, the structure of the present invention will be specifically described with respect to an embodiment shown in the drawings.

The drawing shows an axial sectional view of a fixation device according to an embodiment of the invention. The spindle head 1 of the grinding spindle of a grinding machine has a conical receptacle 2 which is designed as a so-called short conical shape (according to DIN (German Industrial Standard) 55021 or other shapes). There is. The axial length of short conical bodies of this type is always less than 1/5 of their maximum diameter; the larger the diameter, the smaller the ratio of axial length to diameter. If the maximum diameter is approximately 140 mm, the axial length of the conical portion is approximately 14 mm, or 1/10 of the maximum diameter. A radially extending annular flat surface 3 adjoins the conical receptacle 2 . This flat surface 3 is arranged concentrically with respect to the maximum diameter of the conical receptacle 2. A pull rod 4 is also mounted on the grinding spindle 1' for axial movement. This tension rod 4 has a tensioning chuck 5 at its front end. The movement of the pawl 5a of the clamping chuck 5 is controlled by an annular step 6. Further, a centering bush 7 is fixed within the spindle head 1, and this centering bush 7 has a centering hole 8 concentric with the spindle axis A.

The receiving flange 9 for the grinding wheel 10 consists of a stationary flange part 9a and a movable flange part 9b in a known manner. This movable flange part 9
b is adapted to be screwed and fixed to the immovable flange portion 9a by a plurality of screws 11,
As a result, the grinding wheel 10 has two flange portions 9.
It is tightened between a and 9b.

The stationary flange part 9a is provided with a conical receiving hole 12 which matches the conical receiving part 2. The end surface of the immovable flange portion 9a on the spindle head 1 side is configured as a flat abutment surface 15,
This contact surface 15 is supported by the flat surface 3. The abutting surface 15 annularly surrounds the conical receiving hole 12 . A tightening pin 14 is inserted into a hole 13 at the center of the immovable flange portion 9a. The flange portion 14a of this tightening pin 14 is the immovable flange portion 9.
screwed into a. The clamping pin 14 has its end directed towards the spindle head a clamping head 14b.
have. A conical guide section 14c follows this clamping head 14b in the direction towards the stationary flange section 9a. This conical guide part 1
4c advantageously has a tip angle μ of approximately 30°,
This tip angle μ is significantly larger than the tip angle μ1 of the conical receptacle 2, which forms approximately 14°. The conical guide portion 14c has a centering cylinder 14d that fits within the centering hole 8 with play.
It is continuing. In this case, the difference in diameter between the centering bore 8 and the centering cylinder 14d must be smaller than the difference between the maximum diameter of the conical receiving bore 12 and the minimum diameter of the conical receiving part 2.

The centering cylinder 14d also extends in the direction of the clamping head 14b to such an extent that, when changing the grinding wheel, the conical receiving hole 12 is pre-engaged in the centering hole 8 before reaching the conical receiving part 2. It is important that For this,
The centering cylinder 14d projects slightly beyond the abutment surface 15 in the direction toward the spindle head 1.

The stationary flange part 9a furthermore has a projection 16 on the side opposite the spindle head 1. This projection 16 is preferably provided with an annular groove 17 of trapezoidal shape. This annular groove 17 is formed so that a chuck pawl of a conventional replacement tool can be engaged therein. In addition, as shown below the spindle axis A, in the hole 18 of the immovable flange portion 9a,
It is also possible to provide a trapezoidal groove 17' into which the chuck pawl engages from the outside.

In order to avoid damage to the cooperating surfaces during the subsequent pre-centering operation, the centering hole 8,
The surfaces of the conical guide portion 14c and the centering cylinder 14d are hardened.

The mode of operation of the illustrated fixation device will be described below.

The wheel changing device takes out the wheel 10 mounted on the receiving flange 9 by means of chuck pawls that engage in the annular groove 17 and brings it in front of the spindle head 5. The chuck then moves the receiving flange 9 towards the spindle head 5. In this case, first the clamping head 14b and then the conical guide 14c enter the centering hole 8. If the axis of the receiving flange 9 does not coincide with the spindle axis A, the conical guide part 1
4c contacts the opening of the centering hole 8 only on one side. When the receiving flange 9 is moved further towards the spindle head, the conical guide portion 14c
The sloping outer circumferential surface of serves to progressively center the receiving flange 9 with respect to the spindle axis A. Upon further movement of the receiving flange 9, the centering cylinder 14d enters the centering hole 8, thereby causing the receiving flange 9
is precentered relative to the spindle head 1 before the conical receiving hole 12 reaches the area of the conical receiving part 2. By this pre-centering, the conical receiving hole 1 of the immovable flange portion 9a is formed.
2 can be fitted over the conical receptacle 2 without obstruction. Once the receiving flange 9 has been brought into a pre-centered position relative to the spindle head 1, the tightening operation is carried out. When the tightening chuck 5 is moved to the left, its pawl 5a
opens. When the tension rod 4 is moved to the right, the annular step 6 closes the pawl 5a, which grips the tightening head 14b. When the pull rod 4 is moved further to the right, the conical receptacle 12 is completely fitted onto the conical receptacle 2, with the conical receptacle 2 centering the receiving flange 9 in the final working position. . In this working position, the abutment surface 15 abuts against the flat surface 3. The chuck pawl is then released from the annular groove 17 via a set of control members and the grinding spindle 1' is started.

In the fixing device of the invention, it is necessary to arrange the centering and clamping element in the center of the spindle head, so that there is no longer any space for the counterbalancing element, which is normally installed in this position. There are also types of balancing systems in which the annular casing of the balancing device is mounted on the side of the receiving flange opposite the spindle head.
With this type of arrangement, the requirement for complete automation of the grinding wheel change operation is not met.
For these reasons, an annular balancing device casing 19, which is surrounded concentrically by a flat surface 3, is arranged on the spindle head 1 adjacent to the stationary flange 9a. The casing 19 is fixedly screwed to the spindle head 1. Balance systems include commercially available balance systems (e.g. Firma Walter Dittel GmbH,
8910Landesberg's "Hydro Balance Automatic Device") is used. In this balancing device,
The casing 19 is circumferentially divided into three
It is divided into two chambers 20 and 21. The casing 19 has three concentric annular grooves 22 on its back side. Each of these three annular grooves 22 is assigned one of the chambers 20, 21. Each annular groove 22 has a through hole 23 which extends, in the area of the chamber assigned to this annular groove 22, over almost the entire circumferential angle of the associated chamber. Three stationary nozzle heads 24 are provided for supplying the equilibrium liquid, each of these three nozzle heads 24 being assigned one of three annular grooves. Via this nozzle head 24, the chambers 20, 21 of the housing, which is rotated together with the grinding spindle 1', are supplied with a balancing liquid depending on the measurements of the vibration measuring device. In this case, the equilibrium liquid flows out of the nozzle head 24 only when the arch-shaped through hole 23 is present in the area of the nozzle head 24 when the housing is rotated.

Effects As described above, according to the present invention, a device for fixing a grinding wheel on a grinding spindle of a grinding machine equipped with an automatic grinding wheel changing device can avoid the drawbacks of known devices, and moreover, it is possible to avoid the drawbacks of known devices. For this purpose, known chuck devices can be used on milling machines, and there is also less risk of contamination of the conical receptacle, cleaning of the conical receptacle when changing the grinding wheel can be omitted, and thus the working time can be saved. A shortened device was provided.

[Brief explanation of drawings]

The drawing is a schematic axial sectional view of a grinding wheel fixing device according to an embodiment of the invention. 1...Spindle head, 1'...Grinding spindle,
2... Conical receiving part, 3... Flat surface, 4... Tension rod, 5... Tightening chuck, 5a... Pawl, 6... Annular step, 7... Centering bush, 8... Centering hole, 9... Receiving flange, 9a, 9b...flange portion, 10...grinding wheel, 11...screw, 12...receiving hole, 13...hole, 14...tightening pin, 14a...flange, 14b...tightening head, 14c...conical guide part, 14d...centering cylinder, 15... Contact surface, 16... Projection, 17... Annular groove, 17'... Trapezoidal groove, 17a... Trapezoidal groove, 18... Hole, 19... Casing, 20, 21... Chamber, 22... Annular groove, 23... Through hole , 24... Nozzle head, μ... Tip angle of conical guide member, μ1... Tip angle of conical receiving portion.

Claims (1)

[Scope of Claims] 1. A fixing device for a grinding wheel in a grinding spindle of a grinding machine with an automatic grinding wheel changer, comprising a conical receptacle 2 in the spindle head 1 and a tension rod 4 in the central hole. It has a grinding spindle 1' with a clamping chuck 5 actuated by the machine and a receiving flange 9, which comprises a stationary flange part 9a and a movable flange part 9.
These immovable flange parts 9 consisting of
a and the movable flange portion 9b.
is received, and the stationary flange part 9b has on its side facing the spindle head 1 a conical receiving hole 12 which corresponds to the conical receiving part 2 and a central clamping pin 14. have,
The clamping head 14b of this clamping pin 14 is adapted to co-operate with the clamping chuck 5, and the stationary flange 9a, on its side opposite the spindle head 1, is adapted for engagement for a grinding wheel changer. In the version with parts, the conical receptacle 2 is constructed as a short conical body with a radially extending annular flat surface 3 continuous with its maximum diameter, and the immovable Flange part 9
a has an abutment surface 15 that abuts the flat surface 3; the spindle head 1 has a cylindrical centering hole 8 concentric to the conical receptacle 2; a conical guide portion 14 in which the tightening pin 14 is continuous with its tightening head 14b;
c, and the conical guide portion 14c is
The centering cylinder 14d matches the centering hole 8 with play, and the engaging member is connected to the stationary flange portion 9a for engaging the chuck pawl of the grinding wheel changer. It is configured as a concentric annular groove 17 to the extent that the centering cylinder 14d engages in the centering hole 8 before the conical receiving hole 12 reaches the conical receiving part 2 when changing the grinding wheel. A fixing device for a grinding wheel on a grinding spindle of a grinding machine, characterized in that it extends in the direction towards the clamping head 14b. 2. Fixing device according to claim 1, characterized in that the centering cylinder (14d) projects slightly beyond the abutment surface (15) of the stationary flange (9a) in the direction towards the spindle head (1). 3. The fixing device according to claim 1 or 2, wherein the centering hole 8 is provided in a centering bush 7 inserted into the spindle head 1. 4. The fixing device according to claim 1 or 2, wherein the tip angle μ of the conical guide portion 14c is significantly larger than the tip angle μ1 of the conical receiving portion 2. 5. The fixing device according to claim 4, wherein the conical guide portion 14c has a tip angle μ of approximately 30°. 6 Centering hole 18 and conical guide portion 14
Claim 1, wherein the cooperating surfaces of c and the centering cylinder 14d are surface hardened.
The fixing device according to any one of Items 1 to 4. 7. On the spindle head 1, an annular casing 19 of the balance device concentrically surrounding the flat surface 3 is arranged adjacent to the stationary flange part 9a,
A fixing device according to claim 1. 8. The axial length of the conical receiver 2 is equal to or smaller than 1/10 of its maximum diameter,
A fixing device according to claim 1.