DE102014102130A1 - Oscillating drivable machine tool - Google Patents

Abstract

The invention relates to an oscillatingly drivable machine tool with a tool spindle (34) mounted pivotably about its longitudinal axis (35), with a drive motor (14) which is coupled to a hydraulic generator (22) for generating an oscillating fluid flow comprising a hydraulic motor in the form of a hydraulic motor Rotary blade motor (30) drives to rotationally oscillate the tool spindle (34) about its longitudinal axis (35) to drive. The amplitude of the oscillation movement of the tool spindle (34) is adjustable.

Description

The invention relates to an oscillating drivable machine tool with a drive motor and with a tool spindle mounted pivotably about its longitudinal axis, which can be driven in rotation oscillating manner about its longitudinal axis.

Such oscillating drivable machine tools are known in many designs. They are driven by a mechanical oscillation gear, which converts the rotary drive movement of a drive motor into a rotationally oscillating drive movement of the tool spindle about its longitudinal axis.

According to the EP 1 428 625 A1 For this purpose, an eccentric is provided, which cooperates with an eccentric fork for oscillating drive of the tool spindle. The eccentric is driven in rotation by an eccentric shaft, which is arranged parallel to the tool spindle.

According to the EP 2 283 979 A1 an oscillatingly drivable machine tool has a drive motor with a motor shaft, and a tool spindle which can be driven to oscillate about its longitudinal axis, wherein a coupling member rotatably driven by the motor shaft is provided with a closed guide surface which circumscribes a guide axis, wherein the guide surface via transmission means with at least one driver is coupled to the drive, wherein the at least one driver is held movable relative to the work spindle and engages in a peripheral region of the work spindle to drive these rotationally oscillating.

Such mechanical oscillating gears are available in numerous designs in order to convert the rotating drive movement of a motor shaft into the rotationally oscillating movement of the tool spindle.

Because of the ever-increasing demands on the performance of Oszillationswerkzeuge high demands are placed on the mechanical oscillating gear. As a result of the oscillating load, they are exposed to high mechanical stress and thus tend to wear out in long-term operation. At high load also increases the noise. Finally, depending on the load oscillation gearbox lead to more or less large vibrations, which is partially perceived by the user as disadvantageous.

Against this background, the invention has the object to improve an oscillating drivable machine tool according to the aforementioned type such that a drehoszillierender drive the tool spindle is made possible even with high mechanical load in the simplest and most reliable way. Furthermore, the amplitude of the oscillation movement of the tool spindle should also be adjustable.

This object is achieved by an oscillatingly drivable machine tool, with a tool spindle mounted pivotably about its longitudinal axis, with a drive motor which is coupled to a hydraulic generator for generating an oscillating fluid flow which drives a hydraulic motor in the form of a rotary vane motor, around the tool spindle about its longitudinal axis To drive rotationally oscillating, and means for adjusting an amplitude of the oscillation movement of the tool spindle.

The object of the invention is achieved in this way.

By using a hydraulic device for the rotationally oscillating drive of the tool spindle, higher drive powers are made possible than with mechanical oscillating gears, wherein at the same time the wear can be partially reduced and the running smoothness can be improved. The rotary vane motor allows a direct conversion of the pulsating fluid energy in an oscillating movement of the tool spindle, without the need for a mechanical transmission is required. An amplitude adjustment can be integrated here in a simple manner, without the need for a mechanical transmission is required.

A particular advantage of the above arrangement is that by the respective dimensioning of the hydraulic device, the essential parameters of the oscillating drive can be adjusted, so in particular the swing angle, the angular velocity, the angular acceleration and the torque generated. In particular, high torques can be achieved relatively wear and low vibration.

In an advantageous embodiment of the invention, the hydraulic generator is designed as a positive displacement pump, which is coupled via two pulsed fluid pressure oppositely acted outputs with a plurality of fluid spaces, wherein between the two outputs of the positive displacement pump, an adjustable bypass is provided.

In this way, a particularly simple adjustment for the amplitude generated by the hydraulic motor of the tool spindle.

Preferably, in this case, the adjustable bypass is designed as a throttle valve.

According to a further embodiment of the invention, the rotary vane motor rotary vane, which are preferably formed on the tool spindle as a rotary piston fingers, wherein on both sides of each rotary piston finger with a surrounding sleeve fluid spaces are formed, which are coupled with opposite druckpulsierendend acted upon terminals of the hydraulic generator.

In this way, a particularly simple and reliable construction results.

According to a further embodiment of the invention, the adjustable bypass can also be used for setting a central position of the tool spindle.

For this purpose, the adjustable bypass or the throttle valve is normally closed. This results in a rigid hydraulic coupling between the hydraulic generator and the rotary blade motor of the tool axis. By opening the throttle valve, this rigid coupling is separated, the tool axis can now be adjusted manually with little effort in their position.

In this way, the adjustment for the amplitude of the oscillatory movement can be combined with the adjustment of the center position of the tool spindle by using the adjustable bypass. Overall, this results in a particularly simple and inexpensive construction.

According to an alternative embodiment of the invention, the hydraulic generator is designed as a positive displacement pump, which is driven via an eccentric by a motor shaft of the drive motor, wherein the stroke of the positive displacement pump is adjustable via an adjustment of the eccentricity of the eccentric.

Also in this way the amplitude of the oscillatory movement can be adjusted. In this way, a particularly needs-based energy transfer can be achieved. However, the mechanical adjustment of the eccentricity is relatively complicated, since this is a mechanical adjusting or the like. Is required. In addition, a clamping of the eccentric in its position after adjustment is required.

According to a further embodiment of the invention, the positive displacement pump has a driven by a motor shaft of the drive motor via an eccentric linear piston.

In this way, the generation of pulsating fluid energy can be achieved in a particularly simple and reliable manner.

According to an alternative embodiment of the invention, the rotary vane motor has means for adjusting the effective piston area of the vane motor.

In this way, a demand-based energy transfer can be ensured. However, no continuous adjustment of the amplitude is possible.

For this purpose, the hydraulic generator is preferably designed as a positive displacement pump with two pulsating fluid pressure oppositely acted outputs which are coupled to a plurality of fluid spaces, wherein at least two acting in opposite directions fluid spaces by means of associated switching valves can be switched or switched off.

In this way, the amplitude adjustment can be achieved without hydraulic losses. However, only a few amplitude stages, in principle only two stages, can be achieved and a relatively expensive switching valve is necessary.

It is understood that the features of the invention mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Show it:

1 a partial section of an oscillating drivable machine tool according to the invention;

2 a simplified representation of a rotary vane motor according to the invention, according to 1 is used for direct conversion of oscillating fluid energy in an oscillating drive movement of the tool spindle;

3 a schematic diagram of the hydraulic system of the machine tool according to 1 with an amplitude adjustment by means of a bypass throttle;

4 a modified version of the amplitude adjustment means of the output side amplitude adjustment;

5a , b a further modification of the amplitude adjustment by adjusting the Eccentric stroke, with minimal eccentricity according to 5a and maximum eccentricity according to 5b ,

In 1 is an oscillating drivable machine tool according to the invention and shown in total with the numeral 10 designated.

The machine tool 10 has a tool spindle 34 on, in the housing by means of two rolling bearings 26 . 28 around its longitudinal axis 35 is pivotally mounted.

The tool spindle 34 is designed as a hollow spindle, with a received therein, against the force of a spring (not shown) clamped plunger 25 to which a retaining element 27 is fixed. The pestle 25 can by means of a clamping lever 23 over one on the pestle 25 acting eccentric 24 be moved axially against the bias of the spring, including the clamping lever 23 from the in 1 shown clamping position is pivoted forward in a release position. This will be a holding element 27 received clamping element 37 that with a gearing 39 in the holding element 7 engages, relieves, leaving the clamping element 37 can be removed to about one between the outer face of the tool spindle 34 and a head 33 of the clamping element 37 to remove the held tool.

For clamping, the clamping element 37 again through an associated recess of the tool into the tool spindle 34 stuck until the teeth 39 in the holding element 37 engages, and the tension lever 23 back to its cocked position according to 1 emotional.

The tool spindle 34 is about its longitudinal axis 35 with high frequency and in the range of about 5,000 to 30,000 oscillations per minute and low pivoting angle in the range of about ± 1 ° to ± 5 ° (from reverse point to reversal point) drivable. Preferably, the frequency corresponds to the speed of the drive motor used 14 and amounts to about 333 Hz at 20,000 revolutions per minute. The swivel angle from reversal point to reversal point is preferably ± 2.5 °.

To transfer such a high power to the tool spindle 34 In contrast to a known in the prior art mechanical coupling by means of a Oszillationsgetriebes now a hydraulic transmission is used.

This is done by the engine 14 a hydraulic generator driven in 1 only with the numeral 22 is indicated. From the hydraulic generator 22 becomes the oscillating fluid energy via a hydraulic motor 30 that with the tool spindle 34 is coupled, in a rotationally oscillating drive movement of the tool spindle 34 around its longitudinal axis 35 implemented.

The structure of the hydraulic generator 22 is out 2 to see closer.

The motor shaft 15 of the drive motor 14 is at its end where the fan is 17 is received, by means of a rolling bearing 16 on the housing 12 stored. At the end of the motor shaft 15 is an eccentric 18 held on which an eccentric 20 is provided. The eccentric bearing 20 engages in a linear piston 46 one, so that this upon rotation of the motor shaft 15 according to the double arrow 48 is oscillated back and forth in the longitudinal direction. The linear piston 46 acts at its two ends in each case with a pressure chamber 50 respectively. 52 together, leaving in the pressure chambers 50 respectively. 52 located hydraulic fluid by the movement of the linear piston 46 alternately in a pressure chamber 50 and in the other pressure room 52 is compressed.

The complete hydraulic scheme of the machine tool 10 according to 1 is schematic in 3 shown.

In the upper half of 3 is the hydraulic generator 22 represented by the drive motor 14 over the motor shaft 15 and the eccentric driven by it 18 is driven. The eccentric 18 moves the linear piston 46 within a fluid cylinder 54 , In the pressure chambers 50 . 52 at the two ends of the linear piston 46 Thus, each pressure pulsations with opposite signs. The two pressure chambers 50 . 52 of the hydraulic generator 22 are above fluid lines 42 . 43 with the rotary wing motor 30 in connection. The rotary wing motor 30 has in the embodiment shown here two opposing rotary piston fingers 56 on, directly on the tool spindle 34 are formed. The counterpart to the rotary piston fingers 56 on the tool spindle 34 is through a correspondingly shaped socket 32 formed, which preferably consists of bronze.

On both sides of each rotary piston finger 56 is between the tool spindle 34 and the socket 32 one fluid space each 57 . 58 respectively. 71 . 72 educated. Opposite, in the same direction of rotation acting fluid spaces 57 . 72 respectively. 56 . 71 are each together with the associated fluid line 42 respectively. 43 coupled.

In this way, the alternating pressure pulsations in the lines 42 . 43 a rotary pivoting movement of the tool spindle 34 around its longitudinal axis 35 , In 3 are exemplary only two rotary piston fingers 56 indicated, which are arranged opposite to each other. It is understood that preferably also a larger number of Rotary piston fingers can be used, so it is a multi-chamber rotary wing motor. It has proved advantageous if the rotary vane motor is symmetrical with four rotary blades 56 is formed, which are arranged offset at angular intervals of 90 ° to each other.

To avoid overpressure, stand both fluid lines 42 . 43 with a pressure relief valve 64 respectively. 63 in connection. The pressure relief valves 63 . 64 are purely optional. If this is dispensed with, this can be taken into account by sufficient dimensioning. In the limit case, the drive motor 14 slower and thus prevents further pressure increase. By dispensing with the pressure relief valves 63 . 64 is a drift of the tool spindle 34 counteracted from the middle position.

Furthermore, to both lines 42 . 43 via assigned non-return valves 62 respectively. 61 a pressurized fluid reservoir 66 . 67 via a common line 70 connected.

The inevitable in practice fluid losses can be compensated in this way. A suitable amount of hydraulic fluid is for this purpose in a fluid cylinder 66 added. This one is about a piston 67 with the pressure of a suitably sized spring 68 applied.

Thus, in the line 70 set a certain fluid pressure, which may for example be in the range of 2.9 to 5.2 bar. If the pressure falls in one of the two lines 42 . 43 below this value, hydraulic fluid is removed from the fluid cylinder 66 replenished. For this purpose, the check valves preferably have an opening pressure of 0.2 bar.

Between the two lines 42 . 43 attached to the pressure chambers 50 . 52 of the fluid cylinder 54 are connected, is also a bypass 60 arranged in the form of a throttle valve.

By means of the bypass 60 can the amplitude of the oscillation movement of the tool spindle 34 be adjusted continuously.

Also, after opening the bypass 60 The center position of the tool spindle can be adjusted manually.

In 4 an alternative embodiment for amplitude adjustment by means of the hydraulic motor is shown, the total with numeral 30a is designated.

The only difference from the embodiment according to 3 is that on a bypass 60 was omitted and that instead the two fluid spaces 71 . 72 on a rotary piston finger 56 via a valve 74 coupled together. There are two switch positions: In a first position is according to 3 each fluid space is interconnected in each case with the opposite fluid space, so that the fluid spaces 57 . 72 with the line 42 are coupled and the fluid spaces 58 . 71 with the other fluid line 43 are coupled. In a second position of the valve 74 are the two fluid spaces 71 . 72 from the wires 42 . 43 decoupled.

Overall, in this way the effective piston area of the pivot drive can be halved, which leads to a corresponding change in the amplitude. However, only two different amplitudes can be realized here. A constant adjustment is not possible. In addition, results in the configuration described in halved effective piston area a relatively large amplitude of vibration in one-sided force attack on the rotary vane motor, whereby the transverse forces rise on the bearings. This can be prevented with a multi-chamber rotary vane motor.

Based on 5a . 5b a further variant of the amplitude adjustment will be briefly described below.

Here, the resulting eccentricity of the combination of eccentric 18 and eccentric bush 76 adjusted so that the amplitude of the linear cylinder 46 changes. For this purpose, the eccentric bushing 76 in its angular position relative to the eccentric 18 twisted. To adjust a mechanical adjusting gear, such as worm gear used. After completion of the adjustment process, the eccentric 18 opposite the eccentric bush 76 mechanically clamped.

5a shows the maximum lift while 5b shows the minimum stroke.

Such an adjustment of the amplitude is much more complicated than the adjustment by means of a bypass 60 according to 3 or according to the switching valve 74 according to 4 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1428625 A1 [0003]
• EP 2283979 A1 [0004]

Claims (9)

Oscillably drivable machine tool, with one about its longitudinal axis ( 35 ) pivotally mounted tool spindle ( 34 ), with a drive motor ( 14 ) with a hydraulic generator ( 22 ) is coupled to generate an oscillating fluid flow, which comprises a hydraulic motor in the form of a rotary vane motor ( 30 ; 30a ) drives the tool spindle ( 34 ) about its longitudinal axis ( 35 ) to drive in a rotationally oscillating manner, and with means for setting an amplitude of the oscillation movement of the tool spindle ( 34 ). Machine tool according to claim 1, wherein the hydraulic generator ( 22 ) is designed as a positive displacement pump, which has two opposite with pulsating fluid pressure acted upon outputs ( 50 . 52 ) having a plurality of fluid spaces ( 54 . 58 . 71 . 72 ), whereby between the two outputs ( 50 . 52 ) of the positive displacement pump an adjustable bypass ( 60 ) is provided. Machine tool according to claim 2, wherein the adjustable bypass ( 60 ) is designed as a throttle valve. Machine tool according to one of the preceding claims, wherein the rotary vane motor ( 30 ; 30a ) Rotary wing ( 56 ), which preferably on the tool spindle ( 34 ) as a rotary piston finger ( 56 ) are formed, wherein on both sides of each rotary piston finger ( 56 ) with a surrounding socket ( 32 ) Fluid spaces ( 57 . 58 . 71 . 72 ) are formed, which with oppositely druckpulsierend acted upon outputs ( 50 . 52 ) of the hydraulic generator ( 22 ) are coupled. Machine tool according to claim 2, 3 or 4, wherein the adjustable bypass ( 60 ) for setting a center position of the tool spindle ( 34 ) is usable. Machine tool according to claim 1, wherein the hydraulic generator ( 22 ) is designed as a positive displacement pump, which via an eccentric ( 18 ) of a motor shaft of the drive motor ( 14 ), wherein the stroke of the positive displacement pump via an adjustment of the eccentricity of the eccentric ( 18 ) is adjustable. Machine tool according to one of claims 4 to 6, wherein the positive displacement pump one of a motor shaft ( 15 ) of the drive motor ( 14 ) via an eccentric ( 18 ) driven linear piston ( 46 ) having. Machine tool according to claim 1, wherein the rotary vane motor ( 30a ) Medium ( 74 ) for adjusting the effective piston area of the rotary vane motor ( 30a ) having. Machine tool according to claim 8, wherein the hydraulic generator ( 22 ) as positive displacement pump with two outputs acted on opposite with pulsating fluid pressure ( 50 . 52 ) formed with a plurality of fluid spaces ( 57 . 58 . 71 . 72 ), wherein at least two fluid spaces acting in opposite directions ( 71 . 72 ) by means of associated switching valves ( 74 ) can be switched or switched off.

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