Electric machine having angle sensor, in particular hollow shaft encoder

Abstract

The invention relates to an electric machine having an angle sensor, in which a rotor shaft of the electric machine is connected to an attachment shaft, the attachment shaft having a threaded region, a guide region, a cylindrical section acting as a centering fit 3, a second non-circular section, a connection region and a first non-circular section, the rotor shaft having a stepped bore, the thread region is screwed into the internal thread region of the rotor shaft, the thread relief region adjoins the internal thread region of the rotor shaft, and the guide region of the attachment shaft is received with a clearance in the rotor shaft.

Description

Technical Field

[0001] The invention relates to an electric machine with an angle sensor, in particular a hollow shaft encoder / hollow shaft sensor. Background Art

[0002] EP 2 999 094 B1 discloses an attachment shaft for connecting an angle sensor, which attachment shaft is adhesively connected to a rotor shaft of an electric machine and has a ventilation spiral groove.

[0003] A sensor device is known from DE 10 2013 002 049 A1 as the closest prior art.

[0004] An electric motor and an angle sensor are known from DE 10 2019 002 745 A1. Summary of the invention

[0005] The object of the present invention is therefore to improve an electric machine with an angle sensor, in particular a hollow shaft encoder, while providing a highly precise and at the same time easily removable connection between the angle sensor and the electric machine.

[0006] According to the invention, this object is achieved by an electric machine according to the features specified in claim 1 .

[0007] With regard to an electric machine with an angle sensor, in particular a hollow shaft encoder, an essential feature of the invention is that the rotor shaft of the electric machine is connected to the attachment shaft, in particular in a rotationally fixed manner.

[0008] Wherein the attachment shaft has:

[0009] - threaded area,

[0010] - Boot area,

[0011] - a cylindrical section serving as a centering fit,

[0012] - a second non-circular section,

[0013] - connection areas, and

[0014] - a first non-circular section,

[0015] The rotor shaft has a stepped hole, the threaded area is screwed into the internal threaded area of ​​the rotor shaft,

[0016] The thread undercut region adjoins the internal thread region of the rotor shaft, in particular on a side of the internal thread region facing away axially from the guide region.

[0017] wherein the guide region of the attachment shaft is received in the rotor shaft with play, in particular with a clearance fit,

[0018] In particular, the cylindrical section serving as the centering seat has a larger outer diameter than the guide region.

[0019] The advantage here is that the attachment shaft is threaded, wherein it is possible to operate without transverse torques during the threading, since the first non-circular section is easily accessible to the tool without an angle sensor, so that the attachment shaft can be screwed in without transverse forces, i.e., screwed in as far as possible only under the action of a centering torque. Here, when the attachment shaft is inserted, a guide area is provided for pre-centering, and when the attachment shaft is screwed further into the threaded hole, a centering fit takes effect and a stable, load-bearing connection is achieved via the threaded area. As a result, the attachment shaft is aligned with the rotor shaft with high precision, i.e., as precisely as possible.

[0020] The second non-circular section enables simple disassembly, since a high torque can be applied, which may even destroy the additional adhesive. This is because the radial dimension of the second non-circular section is much larger than the radial dimension of the first non-circular section.

[0021] Therefore, the fan mounted on the rotor shaft can only be removed by first removing the attachment shaft. However, the removal of the attachment shaft can be carried out simply and therefore easily. The attachment shaft can then also be installed again, but for this purpose it is necessary to first remove the residual adhesive and then apply new liquid adhesive to the threaded area and the guide area.

[0022] In an advantageous embodiment, the attachment shaft is connected to the hollow shaft of the angle sensor in a rotationally fixed manner. The advantage here is that the hollow shaft is sleeved on the attachment shaft. This allows a simple force-locking clamping connection to be achieved.

[0023] In an advantageous embodiment, a cavity is formed between the guide area and the internal thread area in the axial direction, the cavity being particularly used to receive the adhesive. The advantage here is that the adhesive extruded from the guide area or from the thread area when the attachment shaft is screwed in can be received.

[0024] In an advantageous embodiment, an adhesive is provided between the rotor shaft and the guide region.

[0025] In particular, the adhesive flowing out of the threaded area or the guide area is located in an annular cavity which is delimited radially inwardly by the threaded area and radially outwardly by the stepped bore of the attachment shaft. The advantage here is that the connection of the attachment shaft can be made as stable and load-bearing as possible.

[0026] In an advantageous embodiment, an adhesive is provided between the inner thread region and the thread region.

[0027] Especially wherein, especially the adhesive that flows out from the thread area is located in the thread undercut area. Advantage is here that the connection of the attachment shaft can be made as stable as possible and load-bearing.

[0028] In an advantageous embodiment, the guide region adjoins the cylindrical section which acts as the centering fit. The advantage here is that when the attachment shaft is inserted, the guide section acts first and then the centering fit acts again.

[0029] In an advantageous embodiment, the second non-circular section is arranged axially between the cylindrical section acting as the centering fit and the connecting region. Advantageously, the second non-circular section is arranged outside the stepped bore of the attachment shaft, but as close as possible to the adhesive connection.

[0030] In an advantageous embodiment, the hollow shaft of the angle sensor is connected to the attachment shaft in the connection region, in particular in a force-locking manner. This has the advantage that a simple and highly precisely centered connection of the hollow shaft of the angle sensor can be achieved, wherein the angle sensor can detect the angular position of the hollow shaft relative to the angle sensor housing.

[0031] In an advantageous embodiment, an elastic ring, in particular an O-ring, is arranged between the rotor shaft and the second non-circular section.

[0032] In particular, the elastic ring is arranged radially outside the cylindrical section which serves as the centering fit.

[0033] In particular, the elastic ring bears against the end side of the second non-circular section facing away from the connection region, in particular in the axial direction, and / or against the end side of the rotor shaft facing the second non-circular section, in particular in the axial direction,

[0034] In particular, the ring axis of the elastic ring is parallel to the rotation axis of the rotor shaft. This has the advantage that axial impacts transmitted from the motor to the angle sensor can be attenuated by means of the elastic ring. For example, the elastic ring can also be made of a material such as Teflon. The important thing is to absorb as much of the impact energy as possible.

[0035] In an advantageous embodiment, the first non-circular section adjoins the connection region, in particular on the side of the connection region axially facing away from the second non-circular section. An advantage here is that the first non-circular section forms an axial end region of the attachment shaft and thus a torque can be applied centrally, i.e. without transverse moments, in order to screw the attachment shaft into the rotor shaft.

[0036] In an advantageous embodiment, the fan is placed on the rotor shaft and is connected to the rotor shaft in a rotationally fixed manner.

[0037] The area covered by the fan in the axial direction overlaps with the area covered by the internal thread area and / or the thread back area in the axial direction, or includes the area covered by the internal thread area and / or the thread back area in the axial direction.

[0038] Especially wherein, fan blades equidistantly distributed from each other along the circumferential direction are provided on the fan. Advantageously, when the attachment shaft is removed from the rotor shaft, the fan can be disassembled.

[0039] In an advantageous embodiment, the clear inner diameter of the fan or the outer diameter of the rotor shaft in the region covered by the fan in the radial direction is smaller than the maximum outer diameter of the second non-circular section. The advantage here is that the fan can also be removed after the attachment shaft is removed.

[0040] In an advantageous embodiment, the maximum outer diameter of the second non-circular section is greater than the maximum outer diameter of the connecting region and greater than the maximum outer diameter of the first non-circular section. This has the advantage that large torques can be applied, in particular when removing the attachment shaft.

[0041] In an advantageous embodiment, the first non-circular section is an outer non-circular section, in particular an outer hexagonal section, or an inner non-circular section, in particular an inner hexagonal section. This has the advantage that a torque can be introduced centrally into the center of the attachment shaft using a tool, in particular without transverse moments, in particular when the attachment shaft is screwed into the rotor shaft.

[0042] In an advantageous embodiment, the second non-circular section is an outer non-circular section, in particular an outer hexagonal section. This has the advantage that simple tools can be used.

[0043] In an advantageous embodiment, the first non-circular section is formed on a screw which is screwed into a threaded hole, in particular an axial hole, of the attachment shaft.

[0044] In particular, a washer or a perforated plate is arranged between the screw head of the screw and the attachment shaft. The advantage here is that a non-circular section can be provided by the screw. Therefore, only an axial threaded hole needs to be machined on the attachment shaft and then the screw is screwed in.

[0045] In an advantageous embodiment, the guide region is designed as the outer circumference of the cylinder. This has the advantage that simple and cost-effective production is possible.

[0046] In an advantageous embodiment, instead of the guide region and the cylindrical region acting as a centering fit, a conical region is formed on the attachment shaft, which is arranged axially between the threaded region of the attachment shaft and the second non-circular section.

[0047] In particular, the outer diameter of the conical region increases monotonically, in particular strictly monotonically, with decreasing distance from the second non-circular section. This has the advantage that the attachment shaft can be centered very accurately relative to the rotor shaft.

[0048] In an advantageous embodiment, the hollow shaft of the angle sensor is connected to the connecting region of the attachment shaft in a force-fitting manner.

[0049] A seal, in particular a sealing ring, such as an O-ring, is arranged between the hollow shaft and the second non-circular section, and the seal seals the hollow shaft relative to the second non-circular section.

[0050] In particular, the seal is arranged radially outside the connecting region, so that in particular the radial extent covered by the seal with reference to the rotational axis of the rotor shaft is spaced apart from the radial extent covered by the connecting region with reference to the rotational axis of the shaft,

[0051] In particular, the seal rests against a finely machined end face of the attachment shaft,

[0052] In particular, the end face is designed to be flat, the normal of the end face being parallel to the axis of rotation of the rotor shaft,

[0053] In particular, the housing of the angle sensor is connected to a housing part of the electric motor, in particular a fan cover, by means of a torque support.

[0054] Wherein, a shaft sealing ring is accommodated in the housing of the angle sensor, which is sealed relative to the hollow shaft, and in particular, a sealing lip of the shaft sealing ring abuts against the radial outer circumference of the hollow shaft. The advantage here is that the interior space of the angle sensor can be sealed relative to the environment.

[0055] Further advantages are derived from the dependent claims. The invention is not limited to the feature combinations of the claims. Other reasonable combinations of the claims and / or the features of the individual claims and / or the features of the description and / or the features of the drawings will be apparent to the person skilled in the art, in particular from the stated objectives and / or from the objectives proposed by comparison with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention is now described in detail according to the schematic diagram:

[0057] Figure 1 An attachment shaft 11 connected to the rotor shaft 8 is shown in a sectional view and is used to connect the rotor shaft 8 of the first electric machine according to the invention to an angle sensor.

[0058] Figure 2 The attachment shaft 11 of the second electric machine according to the invention is shown in an exploded oblique view, wherein the Figure 1Unlike the embodiment of FIG. 1 , the attachment shaft 11 has a conical shaft section instead of a cylindrical shaft section, and the screw 20 can be screwed into the axial end of the attachment shaft 11 .

[0059] Figure 3 The rotor shaft 8 with the attachment shaft 11 screwed thereto is shown in a sectional view.

[0060] Figure 4 The attachment of the angle sensor to the first electric machine is shown in a cross-sectional view. DETAILED DESCRIPTION

[0061] like Figure 1 As shown, the first electric machine has a rotor shaft 8 into which an attachment shaft 11 is screwed in order to be able to attach an angle sensor, in particular a hollow shaft encoder.

[0062] The rotor shaft has a trapezoidal hole at its axial end region facing the angle sensor, in particular at its axial end side. The attachment shaft 11 has a threaded region 6, which adjoins the cylindrical guide region 4. Another cylindrical section of the attachment shaft 11, which serves as a centering fit 3, adjoins the side of the cylindrical guide region 4 that is axially away from the threaded region 6.

[0063] Before being connected to the rotor shaft 8 , the threaded region 6 and the cylindrical guide region 4 are coated with an adhesive 9 , which can reach into the cavity 5 or the thread relief region 7 axially adjoining the threaded region 6 of the attachment shaft 11 .

[0064] The stepped bore of the rotor shaft 8 has a thread relief region 7 as the innermost step section, which is arranged axially next to the internal thread into which the threaded region 6 of the attachment shaft 11 is screwed.

[0065] Another stepped section of the stepped hole is arranged axially next to the internal thread, which receives the guide area 4 of the attachment shaft 11 with clearance, especially in a clearance fit. Here, the other stepped section exceeds the guide area 4 in the axial direction, thereby forming a cavity 5, into which the adhesive 9 can reach.

[0066] The further cylindrical section of the attachment shaft 11 has a larger diameter than the guide region 4 and can therefore be inserted without play, in particular as a centering fit, into the further stepped section of the stepped bore of the rotor shaft 8 .

[0067] In this way, when the attachment shaft 11 is inserted into the rotor shaft 8 , guidance is first achieved via the guide region 4 , and when the attachment shaft 11 is screwed in further, precise centering is achieved via the further cylindrical section of the attachment shaft 11 which serves as the centering seat 3 .

[0068] For positioning the tool, the attachment shaft 11 has a first non-circular section 10 at its axial end region facing away from the rotor shaft 8 , so that the tightening torque of the tool can be applied centrally with no or low transverse forces.

[0069] The first non-circular section 10 can be implemented as an outer hexagonal section, such as Figure 1 As shown, it can also be designed as a hexagonal section.

[0070] A second non-circular section 2, in particular with a spanner width, is formed on the attachment shaft 11 in the axial direction between the region 3 acting as a centering fit and the connection region 1. Thus, a further tool can be placed in this second non-circular section 2 in order to be able to dismantle the attachment shaft 11 with a high torque, so that the integral connection is released.

[0071] The attachment shaft 11 may also be referred to as an adapter shaft.

[0072] The maximum outer diameter of the second non-circular section 2 exceeds the maximum outer diameter of the region of the attachment shaft 11 which is received in the rotor shaft 8 .

[0073] The inner ring of the rolling bearing is mounted on the rotor shaft 8, and the outer ring of the rolling bearing is received in the bearing flange. The fan can be mounted on the rotor shaft 8 between the bearing and the second non-circular section in the axial direction and can be connected to the rotor shaft in a non-rotatable manner, especially by a key connection. The maximum outer diameter of the second non-circular section 2 can even be greater than the minimum diameter of the fan, especially greater than the clear inner diameter of the fan.

[0074] The fan can be easily replaced by simply removing the attachment shaft 11.

[0075] like Figure 2 and Figure 3 As shown, instead of the first non-circular section 10, a screw 20 whose screw head has an outer hexagonal section and / or an inner hexagonal section can also be screwed into the threaded hole of the adapter shaft 11. The perforated plate 21 arranged therebetween protects the end side of the attachment shaft 11 facing the screw head of the screw 20. In particular, the perforated plate 21 is arranged between the screw head of the screw 20 and the end side of the attachment shaft 11 facing the screw head of the screw 20.

[0076] In addition, according to Figures 2 to 4 In an embodiment of the present invention, a conical connection area 23 is formed on the attachment shaft 11 instead of the cylindrical guide area 4 and instead of the area which serves as the centering fitting 3.

[0077] The stepped bore has a corresponding inner taper as a further stepped section.

[0078] This results in a better guiding and centering effect.

[0079] like Figure 4 As shown, a fan 40 is mounted on the rotor shaft 8, the fan 40 is connected to the rotor shaft 8 in a non-rotatable manner, and the fan has fan blades. The air flow generated by the fan is deflected by a fan cover 45 connected to the motor housing of the motor, so that the air flow flows along the motor housing.

[0080] The maximum outer diameter of the second non-circular section 2 is greater than the clear inner diameter of the fan 40 .

[0081] The rotor shaft 8 is rotatably supported via a bearing 41 which is received in a bearing cover 42 .

[0082] The attachment shaft 11 can be disassembled using a tool placed at the second non-circular section 2 , so that after disassembling the attachment shaft 11 , the fan cover can also be disassembled and the fan 40 can be replaced.

[0083] The fan 40 cannot be removed without removing the attachment shaft 11 , because the clear inner diameter of the fan 40 is smaller than the maximum outer diameter of the second non-circular section 2 .

[0084] The hollow shaft of the angle sensor is pushed onto the connecting region 1 of the attachment shaft 11 and is connected thereto in a rotationally fixed manner.

[0085] Since the second non-circular section 2 radially protrudes beyond the connecting area 1, the hollow shaft can be tightly connected to the second non-circular section 2 by a seal (especially a sealing ring, such as an O-ring), and thus the internal space of the angle sensor, especially the hollow shaft encoder, can be sealed relative to the environment, because the shaft sealing ring received in the housing of the angle sensor having a housing component 43 seals the housing relative to the hollow shaft 46.

[0086] The hollow shaft 46 is arranged in the angle sensor so as to be rotatable relative to the housing part 43 .

[0087] The seal 44 is arranged radially outside the connecting region 1 , in particular with reference to the axis of rotation of the rotor shaft 8 .

[0088] The housing of the angle sensor is connected to the fan cover 45 via a torque support member not shown in the figure.

[0089] In other embodiments according to the present invention, a polygonal area may also be used instead of the outer hexagonal section or the inner hexagonal section in the first non-circular section 10 and / or in the second non-circular section 2 .

[0090] List of reference numerals:

[0091] 1 Connection area

[0092] 2 The second non-circular section, in particular with a spanner width

[0093] 3 Centering fit

[0094] 4-cylinder guide area

[0095] 5 Cavity

[0096] 6 Thread area

[0097] 7 Thread retraction area

[0098] 8 Rotor shaft

[0099] 9 Adhesives

[0100] 10 First non-circular section, in particular hexagonal section

[0101] 11 Attachment shaft

[0102] 20 Screws

[0103] 21-well plate

[0104] 22 Hexagonal Segment

[0105] 23 Connection area

[0106] 40 Fan

[0107] 41 Bearings

[0108] 42 Bearing cap

[0109] 43 Angle sensors, especially housings for hollow shaft encoders

[0110] 44 Seals

[0111] 45 Fan cover

[0112] 46 Hollow shaft

Claims

1. An electric motor with an angle sensor, in particular a hollow shaft encoder, The rotor shaft of the electric machine is connected to the attachment shaft, in particular in a rotationally fixed manner. It is characterized in that The attachment shaft has: - threaded area, - Boot area, - a cylindrical section which acts as a centering fit (3), - a second non-circular section, - connection area, - a first non-circular section, The rotor shaft has a stepped bore, the threaded region being screwed into the internal threaded region of the rotor shaft. The thread undercut region adjoins the internal thread region of the rotor shaft, in particular on a side of the internal thread region facing away from the guide region in the axial direction. The guide region of the attachment shaft is received in the rotor shaft with play, in particular with a clearance fit, In particular, the cylindrical section which serves as the centering seat 3 has a larger outer diameter than the guide region.

2. The motor according to claim 1, It is characterized in that The attachment shaft is connected to the hollow shaft of the angle sensor in a rotationally fixed manner.

3. An electric machine according to any one of the preceding claims, It is characterized in that A cavity is formed axially between the guide region and the internal thread region, the cavity being used in particular for receiving an adhesive.

4. An electric machine according to any one of the preceding claims, It is characterized in that An adhesive is provided between the rotor shaft and the guide area, In particular, the adhesive, in particular flowing out of the threaded region or the guide region, is located in an annular cavity which is delimited radially inwardly by the threaded region and radially outwardly by the stepped bore of the attachment shaft.

5. An electric machine according to any one of the preceding claims, It is characterized in that An adhesive is provided between the internal thread area and the thread area. In particular, adhesive which flows out from the thread region is located in the thread undercut region.

6. An electric machine according to any one of the preceding claims, It is characterized in that The guide region adjoins a cylindrical section which serves as a centering seat.

7. An electric machine according to any one of the preceding claims, It is characterized in that The second non-circular section is arranged axially between the cylindrical section serving as a centering fit and the connecting region.

8. An electric machine according to any one of the preceding claims, It is characterized in that The hollow shaft of the angle sensor is connected to the attachment shaft in a connection region, in particular in a force-locking manner. and / or, An elastic ring, in particular an O-ring, is arranged between the rotor shaft and the second non-circular section. In particular, the elastic ring is arranged radially outside the cylindrical section which serves as the centering seat. In particular, the elastic ring bears against the end side of the second non-circular section facing away from the connection region, in particular the axial side, and / or against the end side of the rotor shaft facing the second non-circular section, in particular the axial side. In particular, the ring axis of the elastic ring is parallel to the rotation axis of the rotor shaft.

9. An electric machine according to any one of the preceding claims, It is characterized in that The first non-circular section adjoins the connecting region, in particular on a side of the connecting region axially facing away from the second non-circular section.

10. An electric machine according to any one of the preceding claims, It is characterized in that The fan is mounted on the rotor shaft and is connected to the rotor shaft in a non-rotatable manner. The area covered by the fan in the axial direction overlaps with the area covered by the internal thread area and / or the thread relief area in the axial direction, or includes the area covered by the internal thread area and / or the thread relief area in the axial direction. In particular, fan blades are provided on the fan and are distributed equidistantly from one another in the circumferential direction.

11. An electric machine according to any one of the preceding claims, It is characterized in that the clear inner diameter of the fan or the outer diameter of the rotor shaft in the region covered by the fan in the radial direction is smaller than the maximum outer diameter of the second non-circular section, and / or, The maximum outer diameter of the second non-circular section is greater than the maximum outer diameter of the connecting region and greater than the maximum outer diameter of the first non-circular section.

12. An electric machine according to any one of the preceding claims, It is characterized in that The first non-circular section is an outer non-circular section, in particular an outer hexagonal section, or the first non-circular section is an inner non-circular section, in particular an inner hexagonal section, and / or, The second non-circular section is an outer non-circular section, in particular an outer hexagonal section.

13. An electric machine according to any one of the preceding claims, It is characterized in that The first non-circular section is formed on a screw which is screwed into a threaded hole, in particular an axial hole, of the attachment shaft, In particular, a washer or a perforated plate is arranged between the screw head of the screw and the attachment shaft.

14. An electric machine according to any one of the preceding claims, It is characterized in that The guide area is designed as the outer circumference of a cylinder. or, Instead of the guide region and the cylindrical region acting as a centering fit, a conical region is formed on the attachment shaft, which is arranged axially between the threaded region of the attachment shaft and the second non-circular section, In particular, the outer diameter of the tapered region increases monotonically, in particular strictly monotonically, with decreasing distance from the second non-circular section.

15. An electric machine according to any one of the preceding claims, It is characterized in that The hollow shaft of the angle sensor is connected to the connecting region of the attachment shaft in a force-fitting manner. A seal, in particular a sealing ring, such as an O-ring, is arranged between the hollow shaft and the second non-circular section, which seals the hollow shaft relative to the second non-circular section. In particular, the seal is arranged radially outside the connection region, so that, in particular, the radial extent covered by the seal relative to the rotational axis of the rotor shaft is spaced apart from the radial extent covered by the connection region relative to the rotational axis of the shaft. In particular, the seal rests against a finely machined end face of the attachment shaft. In particular, the end face is designed to be flat, the normal of which is parallel to the axis of rotation of the rotor shaft. In particular, the housing of the angle sensor is connected to a housing part of the electric motor, in particular a fan cover, via a torque support. A shaft sealing ring is accommodated in the housing of the angle sensor and is sealed relative to the hollow shaft. In particular, a sealing lip of the shaft sealing ring bears against the radial outer circumference of the hollow shaft.

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