Patent Application
20180318980
The present application claims priority of DE 10 2017 004 252.7, filed May 2, 2017, the priority of this application is hereby claimed and this application is incorporated herein by reference.
The invention relates to a grinding machine for grinding of workpieces with an internal profile, comprising a grinding arm in which at least one grinding wheel is supported for grinding of the profile of the workpiece and a reception which is arranged at the grinding machine for holding the grinding arm.
A grinding machine with such a grinding arm is known from EP 0 416 151 B1. The tubular arm is here driven at one of its axial ends by means of a driving shaft, wherein a pinion is driven around which a toothed belt runs. At the other axial end of the arm a further shaft is arranged which also carries a pinion around which the toothed belt runs. The grinding spindle is then driven via this shaft. The grinding arm is fixed at a reception of the grinding machine at its end remote from the grinding wheel.
Thereby, depending from the workpieces which have to be machined it is necessary to mount a suitable grinding arm into the grinding machine. Accordingly, it is necessary to mount stocked grinding arms into the grinding machine due to the actual grinding task.
Thereby, it is necessary due to economical reasons to execute a change of the grinding arm as quick as possible to keep the dead time of the machine low. At the other hand a very precise positioning of the grinding arm in the grinding machine and thus in the reception for the grinding arm has a significant importance to be able to machine the workpiece precisely.
At pre-known solutions precise ground stop bars are provided for the grinding arm at its reception to be able to arrange the grinding arm relatively to the grinding machine and to the reception respectively in a defined position. Then, the grinding arm is screwed at its reception. Subsequently, the driving belt which at first is loosely applied is threaded and is brought into the required position. Then, the plug for the survey of bursting of the belt and if applicable the alignment sensor or a measuring sensor is mounted as well as the cooling lubricant supply and the oil mist lubrication respectively for the bearings in the grinding arm is connected. After the assembly of the grinding arm is carried out the travelling path is executed and the system is checked with respect to freedom of collisions.
Detrimentally, a relative long assembly time and corresponding know-how are required therefore to carry out a change of the grinding arm.
GB 575 276 A discloses a grinding arm which is fixed at a grinding machine by means of a bifurcated end section. After the grinding arm is mechanically fixed a driving belt is placed and tensioned to be able to drive the grinding wheel of the grinding arm. DE 10 2014 220 161 A1 describes a machining device by which especially radial inner grooves in a vane support can be machined. A grinding wheel which is driven by a grinding spindle is thereby driven via a belt drive. The leaflet “Spanntechnik-Spannende Vielfalt, Stiefelmayer Spannfutter und-dorne” from Stiefelmayer Spanntechnik GmbH & Co. KG discloses clamping mandrels.
It is an object of the invention to further develop a grinding machine of the generic kind for grinding of internal profiles by means of a grinding arm so that it becomes possible to facilitate the change of the grinding arm and thereby nevertheless to ensure a precise position of the same relative to the reception. So, the setup times should be optimized which are necessary for the arrangement of the grinding arm in the grinding machine. Furthermore, the comfort for the machine operator should be enhanced. Potential sources of errors at the assembly of the grinding arm should be eliminated, for example due to a false plugging of tubes or cables or due to a false entry of grinding arm specific data.
The solution of this object by the invention is characterized in that the grinding arm comprises at least two clamping pins being spaced apart from another and that the reception comprises two corresponding recesses for the reception of the clamping pins, wherein in the reception locking means are arranged by which the clamping pins can be locked in the recesses so that the grinding arm is detachably fixed in a defined position relatively to the reception, wherein the grinding arm comprises a driving shaft by which the grinding wheel can be driven, wherein the driving shaft is torque proof connected with a coupling element and wherein in the reception a driving element is arranged which can be brought into torque proof connection with the coupling element.
Thereby it is preferably provided that the coupling element is designed as profile element which comprises around the circumference a plurality of radial protruding projections, wherein the driving element comprises a shape which is complementary to this. In order to bringing together the grinding arm and the reception in an easy manner the coupling element can be designed as part which projects from the base contour of the grinding arm, wherein the driving element in the reception comprises a recess for entry of the coupling element.
Preferably, the rotational movement of the driving shaft is transmitted to a shaft via a belt or a chain which shaft is connected torque proof with the grinding wheel.
In the grinding arm and in the reception detachable coupling means can be arranged for the transmission for a fluid under pressure. Therefore, it is especially considered that the coupling means are designed for the transmission of oil, cooling lubricant or oil mist.
Furthermore, in the grinding arm and in the reception detachable contact means can be arranged for the transmission of electricity or of electrical signals. Thereby, it is possible to establish an electrical connection between the grinding arm and the reception and thus the grinding machine in an easy manner which is for example essential for the survey of the system.
Furthermore, at or in the grinding arm a storage element can be arranged on which grinding arm specific data can be stored. This storage element is preferably designed as a RFID transponder.
Dressable grinding wheels as well as such with a steel base body, which is coated with abrasive material, can be used.
With the proposed solution a repeat accurate and quick change of the grinding arm for the hard fine machining of an internal gearing and internal profile respectively is possible. The time for the change of the grinding arm can thereby be less than 30 s.
So, an optimization of the setup time is possible at the setup of the grinding machine with a grinding arm, wherein a repeat accuracy of the position is possible for the grinding arm at its reception of less than 5 μm.
The required clamping pins and locking means which are required for the proposed concept are known as such and are also called zero-point clamping system. By such means a repeat accurate positioning of the grinding arm at its reception is ensured.
The transmission of media is enabled by the mentioned fluid coupling elements. The required or desired sensor technology is electrically coupled by the mentioned electro couplings. The rotational drive for the grinding wheel is realized by the mentioned pluggable coupling means.
Additionally, a RFID transponder can be provided to store and to recall grinding arm specific data and so to facilitate the mounting process of the grinding arm. Of course also alternative storage means can be provided for the grinding arm specific data like for example a QR code.
It becomes possible by the above illustrated concept to mount in an easy manner and very quick a grinding arm in a grinding machine in precise position; especially, therefore no specific know how is necessary.
As explained above the grinding arm carries the at least two clamping pins while the reception which is connected with the grinding machine comprises the recesses with the locking means. Generally, it is of course also possible in kinematic inversion that the clamping pins are arranged at the reception and that the grinding arm carries the recesses with the locking means. However, this solution is not preferred while not excluded by the present invention.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
In the drawing:
An embodiment of the invention is shown. The only FIGURE shows at one hand a grinding arm for grinding of a not depicted workpiece with an internal profile and at the other hand a reception of the grinding machine for the grinding arm.
In the FIGURE a reception 3 can be seen in the upper left region which is part of a grinding machine. In the right lower region of the FIGURE a grinding arm 1 is depicted which comprises a grinding wheel 2 by which a not shown workpiece with an internal profile can be ground (for example an internal gearing).
Reception 3 and grinding arm 1 are thereby shown in a not yet mounted, i.e. assembled position. When the reception 3 and the grinding arm 1 are mounted the surface 17 of the reception 3 gets in plane contact with the surface 18 of the grinding arm 1.
For a quick mounting of the grinding arm 1 at or in the reception 3 it is provided that the grinding arm 1 comprises two clamping pins 4 and 5 which are spaced apart from another; meanwhile the reception 3 comprises two corresponding recesses 6 and 7 for the reception of the clamping pins 4 and 5. Only schematically depicted are locking means 8 and 9 which are arranged in the reception 3 by which the clamping pins 4, 5 can be latched in the recesses 6, 7. By doing so the grinding arm 1 is detachably fixed relatively to the reception 3 in a defined position.
Concerning the design of the clamping pins 4, 5 and of the locking means 8, 9 reference is made to so-called zero-point clamping systems which are known as such in the state of the art so that their construction needs not to be explained at this point in detail.
When the two surfaces 17 and 18 are brought in plane contact, when thus the clamping pins 4 and 5 are inserted into the recesses 6 and 7, simultaneously a coupling of different elements takes place which are arranged at the or in the reception 3 as well as at or in the grinding arm 1.
An insofar important element is the coupling of the rotary drive for the grinding wheel 2. The grinding wheel 2 is supported at a shaft which—what is not depicted in the FIGURE, however reference is made insofar to EP 0 416 151 B1—is driven by a belt which runs in the inner of the grinding arm 1 which belt runs around a belt pulley which is torque proof connected with the driving shaft 10. Furthermore, a coupling element 11 is torque proof connected with the driving shaft 10 which coupling element comprises a gear-like shape, i.e. several radial protrusions which are distributed around the circumference.
In the reception 3 a corresponding drive element 12 is provided which is driven around an axis of rotation which is perpendicular on the plane of projection by a not depicted motor. The driving element 12 has a shape corresponding to the shape of the coupling element 11, i.e. when the grinding arm 1 is placed onto the reception 3 the coupling element 11, which protrudes from the base contour of the grinding arm 1, enters into the driving element 12 so that a torque proof connection is established by which the driving shaft 10 and so the grinding wheel 2 can be driven.
To enhance the comfort of the change of the grinding arm as well as to reduce the error rate thereby furthermore (two pairs) coupling means 15, 16 and 19, 20 are provided at the grinding arm 1 and at the reception 3 respectively by which a fluidic coupling can be established between the reception 3 and the grinding arm 1. Via this fluidic coupling for example cooling lubricant can be guided to the grinding wheel and/or oil mist can be guided for the lubrication of the bearing to ensure a respective supply.
It is also possible that also more than two pair of said coupling means 15, 16, 19, 20 are provided to transmit further fluids; if there is no respective need for fluids to be transmitted also one pair of coupling means can be sufficient.
Furthermore, electrical contact means 13 and 14 are provided which also automatically get in contact at the mounting of the two surfaces 17 and 18 and allow that electrical energy and electrical signals respectively can be transmitted. Here, for example the electric coupling of a sensor system is relevant by which bursting of the driving belt can be detected. Also concerning the electrical contact means more than one pair can be provided.
Furthermore, a RFID transponder 21 and a corresponding RFID antenna 22 are provided to transmit in an easy manner data from the grinding arm 1 to the reception 3 and machine respectively. At the contact of the surface 18 of the grinding arm 1 at the surface 17 of the reception 3 the transponder and the antenna get in active connection.
To allow a reliable pre-alignment of the grinding arm 1 relatively to the reception 3 furthermore bolts or pins respectively 23 and 24 are provided at the grinding arm 1 for which respective bores 25 and 26 in the reception 3 are provided. Of course, insofar in kinematic inversion the bores can also be arranged in the grinding arm 1 and the bolts and pins respectively can be arranged in the reception 3.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2017 004 252.7 | May 2017 | DE | national |
