DE202013011687U1 - Oscillating drivable machine tool - Google Patents

Abstract

Oscillably drivable machine tool, with a drive motor (12, 54), with a tool spindle (16) mounted pivotably about its longitudinal axis (18), and with a hydraulic device (28, 50, 50a) via which the drive motor (12, 54) the tool spindle (16) is coupled to its rotationally oscillating drive about its longitudinal axis (18).

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.

This object is achieved by a machine tool which can be driven in an oscillating manner, with a drive motor, with a tool spindle mounted pivotably about its longitudinal axis, and with a hydraulic device, by means of which the drive motor is coupled with the tool spindle to its rotationally oscillating drive about its longitudinal axis.

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.

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.

From the DE 20 2008 013 877 U1 While it is known to generate a positive displacement oscillating fluid flow by means of a special rotating spherical segmented fluid generating device. The oscillating fluid flow is converted via a double-acting fluid cylinder into a reciprocating longitudinal stroke of a tool.

From the DE 20 2012 101 137 U1 Further, a hydraulic rotary drive apparatus is known in which an oscillating fluid flow is generated by means of a special rotating spherical segment-shaped fluid generating device. The oscillating fluid flow serves to drive a hydro-rotary actuator with an external rotor, with which an external device in the form of a wing or a fin is driven.

However, the machine tool according to the invention is not suggested by the known hydraulic drive devices, since the drive devices are not suitable for oscillating drivable machine tools, in which the tool spindle is rotationally oscillating driven about its longitudinal axis.

According to a further embodiment of the invention, a hydraulic generator for generating an oscillating fluid flow is provided, as well as a hydraulic motor for converting hydraulic energy into an oscillating drive movement of the tool spindle.

In this way, the oscillating fluid flow can be used in conjunction with a suitable hydraulic motor to produce an oscillating rotational movement of the tool spindle.

According to a further embodiment of the invention, the hydraulic generator has a positive displacement pump.

With such a configuration, no valves in the power flow are required. Furthermore, the translation can be adapted to the desired needs. This results in a low heat generation and high efficiency.

Preferably, the positive displacement pump is designed as a piston pump or as a plunger pump. Further preferred is an embodiment of the hydraulic pump as a double piston pump or as Doppelplungerpumpe.

With such an embodiment of the hydraulic pump, this can be arranged symmetrically, so that a particularly smooth and smooth running results, which is particularly suitable for low-vibration generation of an oscillatory movement of the tool spindle. In an embodiment as a double-piston or Doppelplungerpumpe can be dispensed with an additional mechanical provision (such as a spring element), which would be necessary in a simple configuration.

According to a further embodiment of the invention, the drive motor is designed as an electric motor whose motor shaft is coupled via an eccentric with the hydraulic pump for generating an oscillating fluid flow.

In this way, a very effective implementation of a rotational movement of the motor shaft in an oscillating movement of the hydraulic generator for generating an oscillating fluid flow is made possible.

According to a further embodiment of the invention, the hydraulic motor is designed as a rotary-wing pivot motor (rotary vane motor), which is coupled to the tool spindle to the oscillating drive.

Such a rotary wing motor is particularly well suited to produce an oscillation movement of the tool spindle with limited rotation angle directly without additional gear.

In a preferred embodiment, in this case the rotary vane motor is designed as a multi-chamber rotary motor with at least four chambers.

This has the advantage that the motor can be constructed symmetrically, so that one-sided bearing loads (in the transverse direction) can be avoided.

According to a further embodiment of the invention, the tool spindle is driven by a gear, preferably in the form of a sliding loop, by means of a double-acting cylinder from the oscillating fluid flow.

Even with such an embodiment, the energy of the oscillating fluid flow can be converted into an oscillating movement of the tool spindle about its longitudinal axis in a suitable manner. If the transmission is designed as a sliding loop, a symmetrical design can be achieved.

Basically, an embodiment with a rack as a transmission between the cylinder (linear movement) and tool spindle (oscillation) would be conceivable. However, this would be less favorable than a design as a shear loop.

According to a further embodiment of the invention, the hydraulic generator to an oscillating driven working element, which is driven by the drive motor such that the working element moves as a counterweight in opposite directions to the tool spindle.

Preferably, the working element is designed as a double plunger or as a double piston.

This results in a particularly simple and advantageous construction. In this case, if necessary, a separate balance weight can be dispensed with, since the working element itself can be used as a balance weight in order to achieve a low-vibration running.

According to a further embodiment of the invention, a balance weight is provided, which is driven in opposite directions to the working element. To drive the balance weight, a further hydraulic generator is preferably provided to supply the balance weight with oscillating fluid energy.

In this way, a particularly low-vibration run can be ensured. As a separate drive provided for the balance weight is, this can be optimally adapted to a vibration reduction.

According to a further embodiment of the invention, the hydraulic device has a closed hydraulic circuit.

Such a configuration is particularly suitable for use as a hand-held machine tool.

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 perspective view of an oscillating drivable machine tool according to the invention in a highly simplified representation without the associated housing;

2 a schematic diagram of a rotary vane motor, which is suitable for direct conversion of oscillating fluid energy in an oscillating drive movement of a tool spindle;

2a one compared to the embodiment according to 2 modified version of a rotary vane motor according to the invention;

3 a schematic diagram of a thrust loop with a double-acting cylinder to implement the drive movement of the cylinder in an oscillating drive movement of a tool spindle;

3a one compared to the embodiment according to 3 slightly modified version of a shear loop;

4 a schematic diagram of a hydraulic device with a double piston pump for generating an oscillating fluid flow and with a hydraulic motor for converting the oscillating fluid flow in an oscillating drive movement of a tool spindle and

5 a section through the machine tool according to 1 in which a rotary drive movement of a motor shaft via an eccentric is used to drive a Doppelplungerpumpe that drives the tool spindle directly via a swing-wing motor.

In 1 is a possible embodiment of an oscillating drivable machine tool according to the invention and shown in total with the numeral 10 designated. This is merely an illustration of a purely schematic nature with the essential components, wherein the representation of the housing has been omitted for reasons of simplification.

The machine tool 10 has a tool spindle 16 on, in a basically known manner in the housing (not shown) by means of bearings (only one camp 24 shown) about its longitudinal axis 18 is pivotally mounted. At the upper end is a tension lever 26 pivoted, with which the tool spindle 16 or a clamping element which can be fixed thereto can be displaced axially, around a tool at the outer end of the tool spindle 16 without being able to tighten or release it without the aid of a tool.

The tool spindle 16 is about its longitudinal axis 18 with a relatively high frequency (about 5,000 to 20,000 oscillations per minute) and a small pivot angle (about 0.5 ° to 5 °) pivotable, as by the double arrow 17 is indicated.

To generate this oscillating drive movement is an electric motor 12 provided, which is perpendicular to the tool spindle 16 is arranged in the housing and a hydraulic device 28 with the tool spindle 16 is coupled. At the electric motor 12 is in a known manner to a universal motor, of which in 1 in addition the fan 14 and the collector 15 are recognizable and that with its motor shaft 13 at the outer end by means of a bearing 22 is stored and between fans 14 and hydraulic device 28 by means of another warehouse 20 is stored.

More details, such as the hydraulic device 28 can be basically constructed, are described below on the basis of 2 to 6 explained in more detail.

In principle, the hydraulic device has a generator part in order to generate oscillating fluid energy of a fluid medium from the mechanical rotational movement of a drive shaft. Furthermore, the hydraulic device 28 a motor part, by means of which the oscillating fluid energy in an oscillating drive movement of the tool spindle 16 is implemented.

For the implementation of the oscillating fluid energy in an oscillating drive movement of the tool spindle 16 So, for the hydraulic motor, There are basically a number of possibilities, of which according to the invention an embodiment as a swing-wing motor is particularly preferred.

A first version is in 2 shown. This is a rotary wing swing wing motor (short rotary wing motor) 30 , The simplest version is the execution according to 2 as a two-chamber rotary wing motor.

The particular advantage of a rotary wing motor 30 is that no gear is required.

The rotary wing motor 30 according to 2 has a cylindrical housing 31 on, where on a wave 33 a swing wing 32 is pivotable between two end positions. The swing wing 32 is with two fluid spaces 34 . 35 coupled, via fluid connections 36 . 38 be supplied with oscillating fluid energy.

Will now be oscillating fluid energy to the fluid ports 36 . 38 coupled that first the pressure in the fluid space 35 increases and at the same time the fluid pressure in the fluid space 34 decreases in a corresponding manner, so the swinging wing moves 32 in 2 in the clockwise direction.

In contrast, the pressure conditions in the fluid connections are reversed during the oscillation 36 . 38 So, there is an overpressure in the fluid space 34 and a corresponding negative pressure in the fluid space 35 , so there is a movement of the swing wing 32 in the counterclockwise direction.

Will oscillating fluid energy to the fluid connections 36 . 38 applied, so there is a reciprocating oscillating pivotal movement of the shaft 33 around its longitudinal axis. By means of such a rotary wing motor 30 Thus, thus, the oscillating fluid energy directly into an oscillating drive movement of the tool spindle 16 be implemented when this with the shaft 33 is coupled.

A preferred embodiment according to the invention as a multi-chamber rotary vane motor 30a (see. 2a ) with four or more chambers 34 . 34a . 35 . 35a allows a symmetrical structure, whereby one-sided bearing loads can be avoided.

Another possibility for converting oscillating fluid energy into an oscillating drive movement of the tool spindle 16 consists in the use of a linear piston, longitudinal piston or a double plunger cylinder, each in conjunction with a gearbox.

In 3 is a first embodiment with a double-acting fluid cylinder 42 shown, the oscillating in the longitudinal direction back and forth movement via a gear in a rotational oscillation movement of the tool spindle 16 is implemented. Such an arrangement is called a shear loop 40 designated.

The double-acting fluid cylinder 42 pointing in the direction of the double arrow 43 oscillating drivable back and forth, is with a push rod 44 articulated coupled. The push rod 44 is sliding in a plain bearing 47 led, that at a camp 45 stationary, but is kept pivotable. Moves the fluid cylinder 42 due to alternating fluid energy in the direction of the arrow 43 back and forth, this leads to a reciprocating motion of the plain bearing 47 around the camp 45 as by the double arrow 48 is shown. Will be in stock 45 a fixture 46 for the tool spindle 16 provided, the result is the desired oscillating drive movement of the tool spindle 16 around its longitudinal axis.

More advantageous, however, is a modified embodiment of a sliding loop, which in 3a is shown and total with numeral 40a is designated. Here is the slide bearing 47 directly on the fluid cylinder 42 , so that the tool spindle directly from the swingarm or push rod 44 can be driven and not combined with a plain bearing.

In 4 is the basic structure of a hydraulic device 50 with hydraulic generator 51 for generating oscillating fluid energy and hydraulic motor 58 for the implementation of the oscillating fluid energy in an oscillating drive movement of the tool spindle 16 shown.

In this case, the hydraulic generator 51 a double piston 52 on top of a motor 54 via a connecting rod drive or eccentric drive 56 is driven back and forth. The double piston 52 is movable in an associated cylinder back and forth, at both ends of each a fluid line 53 respectively. 55 connected. Will the engine 54 driven in rotation, so results in the two fluid lines 53 . 55 Thus, an oscillating fluid flow, the implementation in an oscillating drive movement of the tool spindle 16 like using a rotary-wing motor 30 can be used.

The two fluid lines 53 . 55 thus stand with a hydraulic motor 58 in conjunction, which is shown purely schematically and the implementation in the reciprocating drive movement of the tool spindle 16 causes, as by the double arrow 59 is indicated. Although in 4 schematically only one implementation with a double piston on rack and pinion is shown, it is understood that in principle the implementation by means of a rotary vane motor or a sliding loop is preferred.

The hydraulic device 50 is basically designed as a closed hydraulic system. For this purpose, purely schematically a coupling of the two fluid lines 53 . 55 via check valves 62 . 66 with a pressure accumulator 60 indicated. The check valves 62 . 66 are important for the pressure build-up in the system, in which by sucking a negative pressure in the system (at the beginning of movement or by thermal expansion) is prevented. The pressure relief valves 64 . 68 are optional. They should be too high pressure and thus avoid damage. With a suitable design can be dispensed with, for. B. when the power of the drive motor only allows the construction of limited pressures.

On the presentation of further measures, such as to compensate for drift of the tool spindle 16 from their middle position, was omitted here.

Based on 5 Now is a possible construction of the machine tool 10 explained in more detail. 5 shows a longitudinal section through the machine tool 10 according to 1 ,

As already mentioned, it is the drive motor 12 an electric motor in the form of a universal motor. The hydraulic device 28 includes a double plunger pump 74 that from the drive motor 12 via an eccentric 70 is driven and generates an oscillating fluid energy. The oscillating fluid energy is provided by a rotary vane motor 82 directly into an oscillating drive movement of the tool spindle 16 implemented.

The eccentric 70 is at the end of the motor shaft 13 trained and drives over an eccentric 72 a double plunger 76 the double plunger pump 74 oscillating. The double plunger 76 encloses the eccentric bearing 72 from both sides and is thus formed in cross-section approximately U-shaped. This results in a symmetrical arrangement.

Due to the oscillating movement of the double plunger 76 displaces this in the associated fluid spaces in which this dips with its two ends, fluid 80 , so that at the two exits 81 . 83 oscillating fluid energy sets, each with an overpressure at one of the two outputs 81 . 83 and a corresponding negative pressure at the other of the two outputs 81 . 83 , The exits 81 . 83 are now directly with the respective work spaces of a rotary wing motor 82 coupled directly to the tool spindle 16 drives. The oscillating fluid energy of the double plunger pump 74 is thus directly in an oscillating drive movement of the tool spindle 16 around its longitudinal axis 18 implemented.

At the same time the double plunger moves 76 each in the opposite direction as the tool spindle 16 , Thus, the Doppelplunger 76 be provided directly as a balance weight and dimensioned accordingly.

While the rotary wing motor 82 in 5 is shown only as a two-chamber engine for reasons of simplification, an embodiment with four or eight chambers is preferred (see. 2a ), since such a symmetrical structure can be achieved and a one-sided bearing load can be avoided.

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

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]
• DE 202008013877 U1 [0012]
• DE 202012101137 U1 [0013]

Claims (13)

Oscillably drivable machine tool, with a drive motor ( 12 . 54 ), with one around its longitudinal axis ( 18 ) pivotally mounted tool spindle ( 16 ), and with a hydraulic device ( 28 . 50 . 50a ), via which the drive motor ( 12 . 54 ) with the tool spindle ( 16 ) to the rotary oscillating drive about its longitudinal axis ( 18 ) is coupled. Machine tool according to claim 1, with a hydraulic generator ( 51 . 74 ) for generating an oscillating fluid flow, and with a hydraulic motor ( 30 . 40 . 58 ) for the conversion of hydraulic energy into an oscillating drive movement of the tool spindle ( 16 ). Machine tool according to Claim 2, in which the hydraulic generator ( 51 . 74 ) has a positive displacement pump. Machine tool according to claim 2 or 3, wherein the drive motor as an electric motor ( 12 ) is formed, the motor shaft ( 13 ) via an eccentric ( 70 ) with the hydraulic generator ( 74 ) is coupled to produce an oscillating fluid flow. Machine tool according to one of claims 2 to 4, wherein the hydraulic generator ( 74 ) is designed as a plunger pump or as a piston pump. Machine tool according to one of claims 2 to 5, wherein the hydraulic generator ( 74 ) is designed as Doppelplungerpumpe or as a double piston pump. Machine tool according to one of claims 2 to 6, wherein the hydraulic motor as a rotary vane motor ( 30 . 30a . 84 ) is formed, which with the tool spindle ( 16 ) is coupled to the oscillating drive. Machine tool according to claim 7, wherein the rotary vane motor ( 30a ) as a multi-chamber rotary engine with at least four chambers ( 34 . 34a . 35 . 35a ) is trained. Machine tool according to one of claims 2 to 6, wherein the tool spindle ( 16 ) via a transmission, preferably in the form of a sliding loop ( 40 . 40a ), by means of a double-acting cylinder ( 42 ) is driven by the oscillating fluid flow. Machine tool according to one of claims 2 to 9, wherein the hydraulic generator ( 51 . 74 ) an oscillating driven working element ( 76 ) provided by the drive motor ( 12 ) is driven such that the working element ( 76 ) as a counterweight in the opposite direction to the tool spindle ( 16 ) emotional. Machine tool according to Claim 10, in which the working element ( 76 ) is designed as a double plunger or as a double piston. Machine tool according to one of claims 2 to 11, in which a balance weight is provided, which in opposite directions to the working element ( 76 ) is driven, and which is preferably supplied by a further hydraulic generator with oscillating fluid energy. Machine tool according to one of the preceding claims, in which the hydraulic device ( 28 . 50 . 50a ) has a closed hydraulic circuit.

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