WO2008064836A1

WO2008064836A1 - Short design servomotor with angular gear

Info

Publication number: WO2008064836A1
Application number: PCT/EP2007/010210
Authority: WO
Inventors: Roland Schramm; Martin Laupheimer; Bernd Böckenhoff; Dietmar Bühler
Original assignee: Graessner Gmbh & Co. Kg
Priority date: 2006-11-27
Filing date: 2007-11-23
Publication date: 2008-06-05
Also published as: DE102006056238A1

Abstract

A servomotor has an angular gear. The pinion of the angular gear is directly and rigidly connected to the main shaft. A bearing arrangement comprising two tapered roller bearings, which together support the main shaft at this point with respect to all of the axial forces and the radial forces which originate from the angular gear, is positioned between the pinion and the armature of the servomotor. A second deep-groove ballbearing is located on the other side of the armature, with respect to the tapered roller bearing, through which ballbearing the axle is passed in such a way that it is movable in the inner ring of the deep-groove ballbearing.

Description

Short servomotor with angular drive

Servo gear motors are used to move controlled machine parts. For this reason, increased demands are placed on servomotors with regard to the positioning accuracy, since the position is determined exclusively by means of resolvers / incremental encoders arranged in the motor. Particular attention is paid to the gearbox, which reduces the engine speed to the speed required in the machine in one stage. The backlash, which changes dramatically under certain circumstances, has a great influence on the positioning accuracy.

To an increased extent, this applies to servo geared motors which are coupled to the driven part of the machine via a bevel gearbox. The servo geared motor may experience significant temperatures due to start-stop and brake operation. The resulting length expansion of the housing and the armature shaft can be adversely affect the engagement conditions in the bevel gear. To eliminate this, sits in the known today servomotors with bevel gear between this and the anchor a sliding coupling, which is to work without play and creates the length compensation.

By sliding coupling, however, the overall length of the overall arrangement is significantly increased and also it is very difficult to get the sliding clutch clearance and sufficient axialverschieblich.

Based on this, it is an object of the invention to provide a servo geared motor, which is characterized by short length and in any case play-free operation between the motor and pinion of the bevel gear.

This object is achieved with a servo motor assembly having the features of claim 1.

The new servo motor assembly includes a bevel gear having an input bevel gear or pinion and an output bevel gear or crown gear. The output shaft of the bevel gear is mounted in a housing assembly. The Eingangskegelrad or pinion is rigidly fixed against rotation and directly connected to the main shaft, which is aligned at an angle, preferably at right angles, to the output shaft.

Immediately adjacent to the input bevel gear is a first bearing assembly intended to support the main shaft with respect to the axial and radial forces emanating from the bevel gear. As a result, the distance between the bearing assembly, the axial position the pinion defined in the bevel gear, to the input pinion very short, resulting in small magnitude length changes that have no appreciable effect on the meshing ratios in the bevel gear.

From the point of view of the input bevel gear, the armature is on the other side of this first bearing assembly, again in the immediate vicinity. The armature and the input bevel gear are thus rigidly connected to each other directly without any further couplings via the main shaft. The changes in length, which the main shaft and the housing experience due to temperature fluctuations, thus affect mainly in the direction of the engine and thus from the perspective of the bevel gear on the other side of the first bearing assembly. Accordingly, the second bearing for supporting the main shaft is a bearing which is connected via a sliding fit with the main shaft. There occurring radial bearing clearance has, because of the relatively large pointer length, also no effect on the engagement conditions in the bevel gear.

By the special way of accommodating the first bearing arrangement which absorbs the axial forces, the total change in length experienced by the main shaft is split up into a short section in the direction of the pinion and a long section in the direction of the motor and beyond. The short stub axle between the first bearing assembly and the pinion prevents changes in the engagement clearance and in the contact pattern between the bevel gears.

The bevel gear can be a bevel-toothed bevel gearbox, which can be used without axis misalignment. guided, or around a Hypoidgetriebe.

The assembly is simplified when the gear housing assembly is in three parts and consists of a neck portion, a head portion and a lid through which the output shaft passes.

Alignment problems during assembly can be avoided if the neck part and the head part are connected to each other via a centering device.

The first bearing assembly may be advantageously housed in the neck portion of the transmission housing assembly. This arrangement allows, as explained below, the accommodation of two tapered roller bearings.

A very play-free first bearing arrangement can be achieved when two tapered roller bearings are used. These also allow a high radial and axial load.

The production of the main shaft and its connection with the pinion is simplified when the pinion of the bevel gear is made in one piece with a Einsteckschaft. This male shank may preferably be seated with a shrink fit in a bore of the main shaft.

This type of connection avoids any change in the profile of the pinion during the shrinking operation when connecting to the main shaft.

A further simplification of the arrangement can be achieved if the motor has its own housing, the is connected to the neck portion of the transmission housing assembly. As a result, two short housing sections can be achieved, each of which is easy to manufacture on its own and the exterior shape is adapted to the respective requirements.

The housing of the motor may carry on the side remote from the gear housing side a motor cover containing the second bearing assembly.

The second bearing arrangement may be formed by a deep groove ball bearing. The deep groove ball bearing can preferably sit with sliding fit on the main shaft to control the length compensation.

This allows the ball bearing to sit in the housing with a press fit, which is usually made of light metal, while the axle is made of hardened steel. Due to the nature of the arrangement, the wear-prone sensitive sliding bearing pairing is transferred to the hardened steel parts between the ball bearing and the axle. The bearing can also be arranged with a press fit on the shaft and sit in the housing with a sliding seat.

The anchor usually consists of laminations. It is advantageous if the laminated anchor is glued to the main shaft.

The engine is advantageously a brushless motor.

With the main shaft, a brake assembly can be coupled, which from the perspective of the angular gear behind the Motor is positioned.

The conclusion of the arrangement can still form a resolver, sitting in an extension of the motor housing cover.

Incidentally, developments of the invention are the subject of subclaims.

The following description of the figures explains aspects for understanding the invention. Further, not described details, the expert in the usual way the drawings refer to the extent complement the description of the figures. It is clear that a number of modifications are possible.

The following drawings are not necessarily to scale. To illustrate the essential details, it may be that certain areas are exaggerated in size. Moreover, the drawings are simplified and do not include any detail that may be present in the practice.

Fig. 1 shows a servo geared motor assembly in a perspective overall view.

Fig. 2 shows the servo geared motor arrangement according to Fig. 1 in longitudinal section, which contains the axis of the main shaft and the output shaft.

1 shows a servo geared motor arrangement in perspective view. On the servo geared motor assembly 1, an angular gear portion 2, a motor 3, a Brake section 4 and a Resolverabschnitt 5 to distinguish from each other. From the angular gear section 2 projects an output shaft 6 out.

In the region of the brake section 4, an electrical connection fitting 7 can be seen, via which the current is supplied to the brake section 4 and the motor 3. The resolver section 5 is provided with a connection set 8 for data cables.

According to FIG. 2, the transmission section 2 includes a transmission housing arrangement 9, the output shaft 6 and a first bearing arrangement 10 for a main shaft 11 and two bevel gears 12 and 13 which form an angle gear 14.

The transmission housing assembly 10 is divided into a flange 15 and a head portion 16 with a one-piece neck portion 17 which contains a rotationally symmetrical interior.

The flange lid 15 closes an interior 18 of the head part 16 toward the front side. For this purpose, the flange cover 15 is provided with a tubular extension 19 in an opening 20 of the head part 15. The flange cover 15 contains a passage step bore 21, through which the output shaft 6 leads outward from the interior 18.

For storage of the output shaft 6, two tapered roller bearings 22 and 23 are provided, which plug into bearing seats 24 and 25. The bearing seat 24 is formed by a part of the passage step bore 21, while the other bearing seat is contained in the rear wall of the head part 16 opposite to the flange cover 14. The output shaft 6 is inserted with a shaft journal 26 in the tapered roller bearing 23 and with a shaft collar 27 in the tapered roller bearing 22. In addition to the shaft collar 27 is another shaft collar 28 with a smaller diameter shrunk the Ausgangskegelrad or crown wheel 13 carries. A shaft journal 29 eventually leads to the outside.

The seal concerned a lip seal 31 in the through hole 21st

The other bevel gear 12 of the angle gear 14 is rotatably connected to the main shaft 11.

The main shaft 11 is a cylindrical structure whose diameter decreases in stages starting from the pinion 12 to the other end. The bearing of the main shaft 11 takes place on the one hand in the vicinity of the pinion 12 through the first bearing assembly 10 and in the rear area by a deep groove ball bearing 33rd

The first bearing assembly 10 is composed of two tapered roller bearings 34 and 35, which are located in the tubular neck portion 17 and are held at a distance by a collar 36 which protrudes radially inwardly in the tubular interior of the neck portion 17. The collar 36 forms a front contact surface for the outer bearing rings of the two tapered roller bearings 34 and 35 and fixes the position of the first bearing assembly 10 relative to the output shaft 6. Their inner rings are seated on a shaft portion 37 of the main shaft 11. The shaft portion 37 has the largest diameter of all sections of the main shaft 11 and it starts immediately at the pinion 12th The connection between the pinion 12 and the main shaft 11 is done by means of a cylindrical pin 38 which is an integral part of the pinion 12 and which is shrunk into a blind bore 39 which leads coaxially into the main shaft 11 from the front end. The tapered roller bearing 34 adjacent flank surface of the pinion 12 forms the axial bearing surface for the inner bearing ring of the left tapered roller bearing 34th

The axial securing of the main shaft 11, with reference to Fig. 2 to the left, i. in the direction of the bevel gear 13, is done with the aid of a snap ring 41, which sits in a corresponding circumferential groove in the shaft portion 37. In order to obtain the correct preload in the axial direction for the two tapered roller bearings 34 and 35, between the snap ring 41 and the inner bearing ring of the right Kegelrol- lenlagers 35 corresponding shims 42, which are selected during assembly according to the tolerances. The tapered roller bearings 34 and 35 are locked and biased between the pinion 12 and the snap ring 41.

Finally, the neck portion 17 on the right side still contains a lip seal 43, which rests against the shaft portion 37 to the right of the snap ring 41. The tubular neck portion 17 thus includes the two tapered roller bearings 34 and 35 and the seal 43rd

The two tapered roller bearings 34 and 35 are due to their installation position in the immediate vicinity of the pinion 12 able to absorb the radial and axial forces emanating from the pinion 12. Temperature-related changes in length between the transmission housing assembly 9 and the main shaft 11 in this area have no influence the engagement and support conditions between the pinion 12 and the ring gear 13. The backlash will remain largely constant, as it is set at the factory.

To the right joins to the neck portion 17 of the motor 3. To the motor includes a tubular housing 44 in which the field or stator winding 46 is housed. The motor housing 44 is connected to the neck portion via a centering connector 46 so that misalignment between the neck portion 17 and the motor housing 44 is excluded. In the region of the motor 3, the main shaft 11 has tapered to a shaft portion 47, which is significantly smaller than the diameter of the shaft portion 37. On the shaft portion 47 of the armature 48 of the engine is glued. The armature 48 is a laminated squirrel-cage rotor or an armature of a synchronous machine. By gluing the armature 48 with the shaft portion 47 creates a cohesive connection that transmits the required torque and on top of that is very accurate. In addition, a key may be present to produce a positive connection.

At the shaft portion 47, a shaft portion 49 connects, which passes through the deep groove ball bearing 33 and forms a sliding fit with the inner ring of the deep groove ball bearing 33. If thermally induced differences in length between the first bearing assembly 10 and the deep groove ball bearing 33 on the one hand and the longitudinal extent of the main shaft 11 occur in this area, the main shaft 11 remains fixed at the left end of the pinion 12, while 33 can slide slightly in the inner race of the deep groove ball bearing. The deep groove ball bearing 33 is inserted in a bearing seat 50, which is housed in a housing cover 51. The housing cover 51 closes the motor housing 44 to the right.

The housing cover 51 is also connected via a plug connection similar to the connector between the neck portion 17 and the motor housing 44 to the motor housing 44.

The housing cover 51 is cup-shaped extended to the right and includes an electromagnet 52, the brake disc 53 is rotatably connected to the main shaft 11. The pot-shaped extension of the housing bottom 51 forms with a further cover 54 a housing for the electric brake formed by the electromagnet 52 and the brake disk 53 in the brake section 4.

To the right, the arrangement is completed by a resolver 55, which is located in the resolver section 5. Resolver is to be understood here as an incremental encoder.

The entire assembly is held together by screws, which are not illustrated for reasons of clarity.

The assembly of the arrangement is done in such a way that initially through the bore 20, the tapered roller bearing 34 is mounted in the neck portion 17.

In a parallel step, the prefabricated pinion 12 is shrunk into the blind bore 39 of the main shaft 11 with the shaft 38. The subunit formed in this way can then be introduced through an opening 59 in the already mounted tapered roller bearing 34. The opening 58 is located in the head portion 16 of the neck portion 17 and aligned with the tubular interior in the neck portion 17th

Then, the tapered roller bearing 35 is mounted from the right side of the neck portion 17. The washers 41 are pushed onto the shaft portion 37 and the snap ring 42 is inserted. The thickness of the stack of washers 41 is selected so that the two tapered roller bearings 34 and 35 have the prescribed constructive desired axial prestressing.

The access to the pinion 12 through the opening 58 allows to easily attach an abutment tool when the snap ring 42 is set.

Subsequently, if necessary, after insertion of a corresponding feather key, the armature 48 is bonded to the shaft section 47.

In a parallel step, the bevel gear 13 has been placed on the shaft collar 28, for example, by a shrinking process. The inner race of the tapered roller bearing 23 is mounted on the collar 26. Through the opening 20 through the outer bearing ring can now be placed in the bearing seat 25. Subsequently, the conical roller ring is inserted and it is from the opening 20 ago the preassembled output shaft 6, on which possibly already the inner bearing ring of the tapered roller bearing 22 has been plugged mounted. The placement of the flange 15, the outside at the same time a circular centering forms, completes the assembly in the region of the head part 9. It can now be a cover cover 59 are pressed into the previously open aperture 51, whereby the head part 9 is closed. The lip seal 34 may be inserted later or during assembly with the flange cover 15.

After the taper roller bearing assembly 10 is placed in the neck portion 17, together with the main shaft 11, the main shaft 11 is axially immovably connected to the transmission housing assembly 2. The critical dimensions between the pinion 12 and the ring gear 13 are thus clearly specified and independent of the rest of the assembly.

The housing 44 equipped with the stator winding 46 can now be plugged onto the right-hand end side of the neck part 17. Finally, the housing cover 51 is arranged with the deep groove ball bearing 33 seated on the right side of the motor housing.

When the deep groove ball bearing 33 is press fit on the shaft portion 49, it is contained with sliding fit in the seat 50 of the housing. In order to avoid axial vibrations, it is expedient if, based on the illustration of Fig. 2, right of the deep groove ball bearing 33, a wave washer between the outer bearing ring of the deep groove ball bearing 33 and the adjacent base of the bearing seat 50 is inserted.

Now, the housing cover 51 can be plugged. In the cup-shaped interior of the housing cover 51 of the electromagnet 52 of the brake is placed. Subsequently, the brake disc 23 is mounted on the shaft 22, the Cap ^'54 is placed, and the resolver 55 or incremental encoder, depending on the embodiment, is mounted with its static parts in the housing. The rotary or pulse generator is mounted on the main shaft 11. The whole arrangement is closed with a closing lid 57.

Since the neck portion 17 is made of light metal and also the motor housing 44, these two parts will show a different length extension when heated than the main shaft

11 in this section. Because the axial bearing of the pinion

12 takes place in the immediate vicinity of the pinion 12, the length expansion differences of the main shaft 11 and the neck portion 17 in this area are extremely small, so that a total of no negative effects on the engagement conditions between the ring gear 13 and the pinion 12 arise. The new solution uses a continuous main shaft and does not require sliding couplings to control the temperature variation of the arrangement. The difference in length between the extension of the main shaft 11 and the entire housing group is absorbed by the deep groove ball bearing 33, which on the one hand provides the radial bearing of the main shaft 11 in this area and which simultaneously represents an axial sliding bearing for the shaft 11.

The armature 48 is located between the first bearing assembly 10 and the deep groove ball bearing 33. Right of the deep groove ball bearing 33 are only elements with low mass, which have no negative impact on the lying there staggered stub shaft of the main shaft 11.

A servomotor has an angle gear. The pinion of the angular gear is directly connected rigidly to the main shaft. Between the pinion and the anchor of the Servomotor sits a bearing assembly of two tapered roller bearings, which jointly store the main shaft at this point with respect to all axial forces and the radial forces resulting from the bevel gear. From the point of view of the tapered roller bearings is located on the other side of the armature, a second deep groove ball bearing, through which the axis passes so that it is displaceable in the inner ring of the deep groove ball bearing.

Claims

Claims :

1 . Servomotor assembly (1) with a bevel gear (14), the input bevel gear

(12) and a Ausgangskegelrad (13) and whose output shaft (6) is mounted in a housing assembly (9),

arranged at an angle to the output shaft (6)

Main shaft (11) to which the input pinion (12) is rigidly connected,

with a first bearing arrangement (11),

- which is contained in the transmission housing assembly (9),

by which the position of the input bevel gear (12) in the bevel gear (14) is fixed,

- which is the input bevel gear (12) adjacent and

- which is intended to support the main shaft (11) with respect to the axial and radial forces emanating from the bevel gear (14),

with an armature (48) which is non-rotatably mounted on the main shaft (11) and located immediately adjacent to the first bearing assembly (10) on the other side as the Eingangskegelrad (12), and

with a second bearing arrangement (33), by means of which the main shaft (11) at its other end () is rotatably and axially displaceably mounted.

2. servo motor assembly according to claim 1, characterized in that the bevel gear (14) arc-toothed is.

3. servo motor assembly according to claim 1, characterized in that the bevel gear (14) is a hypoid gear ().

4. servo motor assembly according to claim 1, characterized in that the gear housing assembly (9) consists of a neck portion (17), a head part (16) and a lid (15) through which the output shaft (6) passes.

5. servo motor assembly according to claim 4, characterized in that the neck part (17) and the head part (15) forming the housing sections are integrally connected to each other.

6. servo motor assembly according to claim 4, characterized in that in the neck portion (17), the first bearing assembly is housed.

7. servo motor assembly according to claim 4, characterized in that in the head part (16) the bevel gear (14) is included.

8. servo motor assembly according to claim 4, characterized in that the neck portion (17) is substantially in the tubular.

9. servo motor assembly according to claim 1, characterized in that the first bearing assembly (10) is a double-tapered roller bearing assembly (34,35).

10. servo motor assembly according to claim 1, characterized in that the pinion (12) of the bevel gear (14) with an insertion shaft (38) is integrally connected, in a bore (39) of the main shaft (11) sits.

11. Servomotor assembly according to claim 10, characterized in that the insertion shaft (38) in the main shaft (11) is shrunk.

12. Servomotor arrangement according to claim 1, characterized in that the motor (3) has its own housing part (44) is associated.

13. Servomotor assembly according to claim 12, characterized in that the housing part (44) of the motor (3) with the neck part (17) is connected.

14. Servomotor assembly according to claim 10, characterized in that on the housing part (44) of the motor (3) on the side remote from the gear housing assembly (9) side, a motor cover (51) is placed, in which the second bearing assembly (33) is arranged ,

15. Servomotor assembly according to claim 1, characterized in that the second bearing assembly (33) is formed by a deep groove ball bearing, which is arranged with sliding fit in the housing.

16. Servomotor assembly according to claim 1, characterized in that the armature (48) is glued to the main shaft.

17. Servomotor arrangement according to claim 1, characterized indicates that the motor (3) a brushless motor is preferably a synchronous motor.

18. Servo motor assembly according to claim 1, characterized in that with the main shaft (11) a brake assembly (52,53) is rotatably coupled.

19. Servomotor arrangement according to claim 1, characterized in that with the main shaft (11) of the encoder of a resolver (55) is coupled.

20. Servomotor assembly according to claim 1, characterized in that the braking device (52,53) and the resolver (55) are housed in a tubular extension of the motor cover (51).

21, servo motor assembly according to claim 1, characterized in that between the first bearing assembly (10) and the motor (3) a lip seal (43) is provided.