DE7336122U - Electronically controllable electrohydraulic stepper motor for driving machine parts to be moved step by step - Google Patents

Description

Electronically controllable electrohydraulic stepping motor for driving machine parts to be moved step by step.

The innovation concerns an electronically controllable stepper motor For driving machine parts that are to be moved step by step, such as dividers, feed units, etc., consisting of an electrical part (electronically controllable stepper motor) and a hydraulic part (hydraulic torque booster / hydraulic Motor and controllable valve).

In machine tool construction in particular, it is often necessary to remove machine axes and workpieces (material strips, blanks etc.) to shift or twist intermittently by a certain distance or angle.

This requirement was previously solved by so-called mechanical stepping mechanisms with manual transmission. Through the current Braking and accelerating the gearbox was particularly evident when there were high numbers of steps per unit of time After a relatively short working time, wear and tear would inevitably lead to inaccuracies.

In order to achieve an improvement here, one has recently switched to using electric stepper motors, which offered themselves as an ideal drive element. After the stepper motors were used for some time in VJerkzeugmaschinen for positioning of workpieces with success, they have proven si ch as a drive, for example, dividing heads and feeders.

A major advantage of the stepper motor as a drive for positioning operations results from the fact that the stepper motor is able to take a predetermined number of steps

7336122-10.10.74

exactly to be executed on a distance or angle measuring device to check the Iat value can be dispensed with.

A stepper motor is essentially different from ei nem stepping mechanism, which has a mechanical detent and by electrical impulses on a magnet mechanically further rotated v: ird, in that it is an electromagnetic Has "latching" that holds it in its current position by the fact that a certain winding or a Winding group is excited.

One embodiment, for example, contains five axially strung together magnetic systems, each with a ring winding in the stator. Are the '.Jicklungs one after the other in certain Sequence, the motor is turned one step further with each switching. Due to the simultaneous Excitation of two or three windings halves the torque per step. The order of the calculated windings determines the direction of rotation of the stepper motor, while the chronological sequence with which the various windings be switched on one after the other (font frequency), the Speed of the motor influenced.

Since the electric stepper motor cannot process electrical impulses directly, it still has an electronic one Control device that converts the incoming pulses into signal combinations for the control windings of the stepper motor.

The torque that can be achieved with the purely electric stepper motor but is not sufficient for many technical applications. For this reason one has gone over to the electric stepper motor to connect a torque amplifier, e.g. a hydraulic motor, and thus an essential To achieve reinforcement. This combination is under the technical name "electrohydraulic stepper motor" known.

With these electrohydraulic stepper motors, the electric stepper motor from the electronics attached to one Decade switch set number of pulses. Based on these The electric stepper motor executes a certain angle of rotation with a servo sensor of the hydraulic torque booster is rotated by exactly the same angle, thereby exposing bores through which the oil can pass through the working pistons and the output shaft via the swash plates set in rotary motion, which is carried out as long as until the output shaft has covered the same angle as the servo sensor ο After that, the flow rate in the control plate interrupted again »

The entire structure and mode of operation of the purely electric and electrohydraulic stepper motors is from the Special print "Electrical and electrohydraulic stepper motors" from the magazine "Steuerungstechnik", 1st year, Issue 1, 1968, pages 13-18.

Now, however, are very specific machine tools, such as partial devices for slot punching as well as with linear sub-devices such as roll feed units in automatic punching machines to meet two important requirements, among other things. These are:

a) high partial speed and

b) high triggering capacity, i.e. small angles of rotation on the output shaft of the hydraulic stepper motor per pulse.

In the case of the electric stepper motors, however, the rnax. Frequency set a limit, i.e. with these stepper motors it is possible to achieve a high speed if the resolving power is made small or the partial path per pulse of the motor is large, or the partial path per step of the stepper motor is very small: thus however, the T'i! speed is determined by the maximum step frequency limited, also small.

This is where the present innovation comes in and has set itself the task of those mentioned under points a) and b) To optimally meet requirements while avoiding the aforementioned disadvantages.

To solve this problem, an electrohydraulic Stepper motor of the embodiment described at the outset proposed that the electrical part consists of two or more There is stepper motors that share a special gear such as differential gear etc. with the servo sensor of the Cooperate valve.

Another characteristic of v. Is seen in the fact that the stepper motors have a different resolution.

A preferred construction according to the innovation is characterized in that the output gear of a stepping motor meshes with a pinion which simultaneously cooperates with the drive gear of the scrvo sensor of the valve, unc Both gear wheels have a difference in the number of teeth with the same module and the same pitch circle diameter. It is still there It is advantageous that the pinion is mounted in a housing, which in turn can be rotated in the fixed stepper motor housing is mounted and has an outer ring gear which together with the output gear of the other stepper motor rk t.

The new design enables the servo sensor to be rotated very sensitively, for example by using the one stepping motor has a large partial speed, while the other stepping motor enables precise fine adjustment or positioning takes place. The stepper motors can be controlled simultaneously or in any sequence because the rotary movements carried out by the stepper motors can be superimposed. .

With the same resolution of the two stepper motors by the downstream special gear depending on the between

733612210.10.74

Output and drive gear selected difference in number of teeth the angle of rotation of the stepper motor, which acts on the servo sensor via the special gear, corresponds to the Transfer reduced reduction ratio to the servo sensor. This effect allows very small angles of rotation the output shaft of the hydraulic motor can be achieved without a loss of speed due to the limitation the maximum possible step frequency. the large angle of rotation to achieve a high speed on the output shaft of the hydraulic stepper motor are driven by the electric stepper motor, which drives the servo sensor via the output, drive gear and pinion, achieved.

The innovation is based on a drawing showing a longitudinal section through the new electrohydraulic stepper motor represents, explained in more detail.

The electrohydraulic stepper motor essentially consists of the hydraulic part 1 and the electrical part 2. A gear housing 3 is permanently connected between the two parts. The electrical part consists of the one shown Motor version consisting of two electrically controlled stepper motors 4 and 5, both of which are fixed to the gearbox housing 3 are attached. On the output shaft 6 of the stepper motor 4 sits a driven gear 7, which meshes with a pinion 8 which is rotatably mounted in a housing 9, which has an outer ring gear 10. The housing 9 is rotatably mounted in the gear housing 3. The pinion 8 acts simultaneously with the drive gear 11, which is generally designated 13 on the servo sensor 12 of the Valve is seated. The servo valve does not have to be arranged to rotate, but can also be longitudinally displaceable be formed.

Seated on the output shaft 14 of the second stepping motor 5 a gear 15 which cooperates with the ring gear 10 of the housing 9. It is also important that the two gears 7 and 11 a difference in the number of teeth with the same rolling

733612210,10.74

• · · ti I

O *

« 4

- » ■» τ

circle sclurchrnesser show.

The motor works as follows:

The stepper motor Λ drives the output gear .d 7. This causes the pinion 8 to rotate, which in turn drives the drive gear 11 of the servo sensor 12.

As already mentioned, the drive 2; gear 11 opposite the From the drive tooth in wheel 7 there is a difference in the number of teeth, but has the same Vj'älzkreis. If the stepper motor Ί is now via the Similar to simplicity, electrical control is not shown When activated, the power flow goes from the output gear 7 via the pinion S to the drive gear 11 and thereby drives the servo sensor 12.

When the stepping motor 5 is activated, the gear 15 is driven to the ring gear 10 of the housing 9. If now the stepper motor 4 is at a standstill, the pinion 8 is set in a circular motion via the ring gear 10 and rotates at the same time early around its own axis.

But after the output gear 7 and the drive gear 11 have a difference in the number of teeth, a very sensitive one takes place Rotation of the drive gear 11 and thus a sensitive rotation of the servo sensor 12, which controls the control of the valve 6 takes over. This happens because the gear 15 of the stepping motor 5 drives the ring gear 10. Due to the arrangement of the specially designed gear, the stepping motor 4 can achieve a large partial speed can be achieved, while the other stepper motor takes over the fine adjustment or positioning.

733612210.10.74

Claims (4)

Protection claims 1. Electronically controllable electro-hydraulic stepper motor For driving machine parts that are to be moved step-by-step, such as dividing heads. Feed devices, etc., consisting of an electrical part (electronically controllable stepper motor) and a hydraulic part (hydraulic torque booster / hydraulic motor and controllable Valve), characterized in that the electrical part (2) consists of two or more Stepper motors (4, 5) ordered that share a special gear, such as differential gear, etc. with the Servo sensors (12) of the valve (13) interact. 2. stepper motor according to claim 1,
characterized in that the stepping motors (4, 5) have different resolution capabilities. 3. Stepper motor according to claim 1 and 2, characterized in that that the drive gear (7) of a stepping motor (4) meshes with a pinion (8), which simultaneously with the Drive gear (11) of the servo sensor (12) of the valve (13) cooperates, and both gears (7, 11.) with the same Module and the same pitch circle diameter a difference in the number of teeth have = 4. stepper motor according to claim 3,
characterized in that the pinion (3) is mounted in a housing (9) which in turn is rotatably mounted in the fixed gear housing (3) and has an outer toothed ring (10) which is connected to the output gear (15) of the other stepper motor ( 5) cooperates. 733612210.10.74