Assembly with rotary encoder and tolerance sleeve

Abstract

The invention relates to an assembly with a rotary encoder and a tolerance sleeve, comprising a rotary encoder (1), a tolerance sleeve (2) and a main body (3) which accommodates the rotary encoder and the tolerance sleeve (2). The housing (1.21) has an outer wall which has a special geometry. The main body (3) has a recess (3.1), the inner wall (3.11) of which is also specially shaped. The tolerance sleeve (2) surrounds the housing (1.21) and is arranged in the recess (3.1) in such a way that the tolerance sleeve (2) is clamped radially.

Description

Technical Field

[0001] The present invention relates to an assembly having a rotary encoder and a tolerance sleeve, and a body accommodating the rotary encoder and the tolerance sleeve, according to the present invention.

[0002] Rotary encoders are used, for example, to determine the angular position or rotational speed of two machine parts that can rotate relative to each other.

[0003] In inductive rotary encoders, excitation and receiving traces are often arranged, for example, as printed wires across a main multilayer printed circuit board, which is fixedly connected to the stator of the rotary encoder. A scale element is arranged opposite this printed circuit board, with a graduation structure on it, and is torsionally connected to the rotor of the rotary encoder. When a time-alternating excitation current is applied to the excitation coil, a signal related to angular position is generated in the receiving coil during the relative rotation between the rotor and stator. These signals are then further processed in evaluation electronics.

[0004] In rotary encoders that operate based on optical principles, light is often modulated by a rotating disk with a graduated structure. The modulated light is then received by a photodetector. The intensity of the received light contains information about the relative angular position.

[0005] Such rotary encoders are frequently used as measuring devices in motor drives to determine the relative motion or position of corresponding machine parts. In this case, the generated angular position values ​​are transmitted to electronic equipment via a corresponding interface device for drive control. Background Technology

[0006] A rotary encoder is known from US 2009 / 0027043 A1, which can be mounted on another body by means of an annular tolerance sleeve.

[0007] The disadvantage of such a device is that, during its operation, it can impair the measurement quality or accuracy of the rotary encoder. Summary of the Invention

[0008] The purpose of this invention is to provide a component that enables the reliable operation of a rotary encoder with high measurement accuracy.

[0009] According to the present invention, this objective is achieved through the features of the present invention.

[0010] Accordingly, the components according to the invention include a rotary encoder, a tolerance sleeve, and a body accommodating the rotary encoder and the tolerance sleeve. The rotary encoder has a shaft at which a scale element is torsionally fixed. Furthermore, the rotary encoder has a housing in which a scanning unit is arranged, the scanning unit being torsionally connected to the housing. The shaft is rotatably arranged relative to the housing about an axis. The scale element can be scanned by the scanning unit. Additionally, the housing has an outer wall, preferably designed as a closed annulus, with a first radial distance to the axis in a first section and a second radial distance to the axis in a second section. Where applicable, the first distance is greater than the second distance. Furthermore, the body has a recess accommodating the rotary encoder and the tolerance sleeve. The recess is radially defined relative to the axis by a first inner wall, wherein the first inner wall has a third radial distance to the axis in a third section. Furthermore, the first inner wall has a fourth radial distance to the axis in a fourth section. The body is designed such that the fourth distance is greater than the third distance. Furthermore, the void is defined by a second inner wall, which forms an axial stop for the housing relative to the axis, wherein a fourth segment is arranged axially between the second inner wall and the third segment. Therefore, the fourth segment is closer to the second inner wall relative to the axial direction than the third segment. A tolerance sleeve surrounds the housing and is arranged in the void such that the tolerance sleeve is radially positioned between the first segment and the fourth segment. Similarly, in the assembled state, the tolerance sleeve is located between the second segment and the third segment, wherein the tolerance sleeve is radially clamped between the housing and the body.

[0011] The first, second, third, and fourth segments extend in the axial direction, wherein the first and / or second segments can be regions on the convex surface of the cylindrical outer contour of the housing, while the third and / or fourth segments can be regions on the convex surface of the cylindrical inner contour of the open portion. However, the segments involved need not be necessarily closed annular surfaces; more precisely, these surfaces can also be interrupted circumferentially.

[0012] Therefore, the second inner wall has such an orientation that the normal vector on the inner wall has a directional component parallel to the axis.

[0013] The component is advantageously designed such that the second inner wall forms an axial stop for the tolerance sleeve.

[0014] In another design of the present invention, the housing has a first conical surface between the first segment and the second segment.

[0015] Advantageously, the first inner wall has a second conical surface between the third and fourth sections.

[0016] The conical surface is appropriately arranged relative to the axis. The conical surface can be designed as a closed ring or as a surface interrupted on the circumference.

[0017] Advantageously, the shell has an annular outer wall.

[0018] In another design of the present invention, the first inner wall has an annular inner contour.

[0019] Rotary encoders are generally classified into those with built-in bearings and those without (hereinafter referred to as bearingless rotary encoders). Rotary encoders with built-in bearings typically have relatively small rolling bearings, allowing the assemblies of components that can rotate relative to each other to be arranged relative to each other in defined axial and radial positions within the encoder. Conversely, when installing a bearingless rotary encoder at a machine, care must be taken to ensure that the assemblies of components that can rotate relative to each other are fixed in the correct position, particularly with the correct axial spacing, and that this position remains constant during operation of the rotary encoder. In particular, the present invention advantageously incorporates bearingless rotary encoders.

[0020] Advantageous designs of the invention are given in the dependent claims.

[0021] Further details and advantages of the rotary encoder according to the invention will become apparent from the following description of embodiments according to the accompanying drawings. Attached Figure Description

[0022] Figure 1 It is an exploded view of the components.

[0023] Figure 2 This is a cross-sectional view of a rotary encoder.

[0024] Figure 3 This is a cross-sectional view of the main body, which serves as the motor housing.

[0025] Figure 4 It is a cross-sectional view of the component.

[0026] Figure 5 It is based on Figure 4 Detailed cross-sectional view. Detailed Implementation

[0027] according to Figure 1 The present invention relates to a component comprising a rotary encoder 1, a tolerance sleeve 2, and a body 3, such as a motor housing of an electronic driver.

[0028] Accordingly, the rotary encoder 1 includes a first component group 1.1 and a second component group 1.2, wherein the component groups 1.1 and 1.2 are rotatable relative to each other about axis A. Typically, the first component group 1.1 is used as the rotor and the second component group 1.2 is used as the stator.

[0029] The first component group 1.1 includes a shaft 1.11 or a rotary encoder shaft. A scale element 1.12 or a caliper is torsionally fixed at the shaft 1.11 of the rotary encoder 1. The scale element 1.12 includes graduations, wherein, in the current embodiment, the scale element 1.12 is constructed as a disk made of printed circuit board material, with graduations arranged on the annular surface of the end side of the disk. The scale element 1.12 consists of a substrate, which in the illustrated embodiment is made of epoxy resin, and one or more graduation tracks are arranged thereon and centered relative to axis A. The graduation tracks typically consist of a periodic sequence of alternating conductive and non-conductive graduation regions, respectively.

[0030] The housing 1.21, belonging to the second component group 1.2, includes a cover plate 1.213 and serves to protect the internal cavity of the rotary encoder 1 from environmental influences. A scanning unit 1.22, torsionally fixed relative to the housing 1.21, is located inside the housing 1.21, defining the scanning element for detecting the angular position between the scanning unit 1.22 and the scale element 1.12. In this current embodiment, the rotary encoder is based on an inductive scanning principle. The scanning unit 1.22 includes a multi-layered printed circuit board 1.221. Two of these layers are structured such that they serve as receiving printed conductors and excitation printed conductors. Furthermore, an electrical component 1.222 is mounted on the printed circuit board 1.221. Circuitry is required to operate the excitation printed conductors and to process the signals received by the receiving printed conductors. The electrical component 1.222 is part of this circuitry, providing excitation to the printed conductors and processing the received signals. Additionally, an electrical coupling is mounted on the printed circuit board 1.221 for establishing a mating connector connection with a cable.

[0031] In the current embodiment, the rotary encoder 1 is designed as a bearingless rotary encoder, that is, no bearings, particularly rolling bearings, are arranged between the first component group 1.1 and the second component group 1.2. Therefore, the first component group 1.1 can move relative to the second component group 1.2 within certain limits, particularly in the axial direction.

[0032] according to Figure 2 The housing 1.21 has a protruding outer wall, which has a first radial distance R1 to axis A in the first segment 1.211. In the illustrated embodiment, the first segment 1.211 is designed as a cylindrical cover. The first distance R1 is considered to be the distance between a point on the aforementioned cover and axis A.

[0033] In other words, in the first section 1.211, the outer diameter of the housing 1.21 is twice the first spacing R1 (2xR1).

[0034] The outer wall of the housing 1.21 has a second segment 1.212 that is axially offset from the first segment 1.211. In the second segment 1.212, which can also be considered as a cylindrical cover, the outer wall of the housing 1.21 has a second radial distance r2 to the axis A. Because the outer diameter of the housing 1.21 in the second segment 1.212 is smaller than the outer diameter of the housing 1.21 in the first segment 1.211, the first distance R1 is greater than the second distance r2.

[0035] In addition, according to Figure 1 The component includes a tolerance sleeve 2. This tolerance sleeve surrounds the housing 1.21. As is conventional, the tolerance sleeve 2 has stamped reinforcing ribs 2.1. In the corresponding installation, the reinforcing ribs 2.1 of the tolerance sleeve 2 act like radially compressed pressure springs.

[0036] Finally, the assembly includes a main body 3, which, as described above, is at this point the motor housing. The main body 3 has a recess 3.1, which can also be referred to as a bottom-cut hole. According to... Figure 3 The open portion 3.1 is defined in the radial direction by a first annular inner wall 3.11. This first inner wall 3.11 has a third radial distance r3 to axis A in the third segment 3.113 and a fourth radial distance R4 to axis A in the fourth segment 3.114. The fourth distance R4 is greater than the third distance r3.

[0037] Furthermore, the empty portion 3.1 is defined by a second inner wall 3.12. The second inner wall 3.12 is spatially oriented such that a normal vector extends parallel to axis A on the surface of the inner wall 3.12. In the illustrated embodiment, the second inner wall 3.12 is flat. The body 3 is designed such that a fourth segment 3.114 is arranged axially between the second inner wall 3.12 and the third segment 3.113. Furthermore, the second inner wall 3.12 has a centrally located hole in which the motor shaft 4 can be accommodated. This hole has an interference fit with the motor shaft 4, thereby allowing the motor shaft 4 to rotate freely within the hole.

[0038] During the installation of the rotary encoder 1 in the main body 3 or in the motor housing, the rotary encoder 1, together with the tolerance sleeve 2, is pressed into the recess 3.1 of the main body 3. In this case, the second inner wall 3.12 forms an axial stop relative to axis A for the housing 1.21 and for the tolerance sleeve 2. Figure 4 The housing 1.21 of the rotary encoder 1 is now securely and centrally fixed in the body 3 by means of the tolerance sleeve 2 through a press fit.

[0039] Finally, it is possible to base on Figure 4The first component group 1.1 of the rotary encoder 1, in particular the shaft 1.11, is screwed together with the motor shaft 4 (with screws), wherein the first component group 1.1 is pressed against the shoulder of the motor shaft 4 by the central bolt.

[0040] By striking the motor shaft 4 with the shaft 1.11 of the rotary encoder 1 and the housing 1.21 striking the second inner wall 3.12, the first component group 1.1 is precisely positioned relative to the second component group 1.2 in the axial direction. Therefore, the so-called scanning interval z between the scale element 1.12 and the scanning unit 1.22 is precisely adjusted after installation.

[0041] During relative rotation between the scale element 1.12 and the scanning unit 1.22, a signal related to the corresponding angular position is generated in the scanning unit 1.22 through a sensing effect. For accurate measurement of the angular position, it is important that the signal amplitude reaches a sufficient magnitude. Furthermore, the magnitude of the signal amplitude is also related to the scanning spacing z. To avoid changes in the scanning spacing z by only a fraction of a millimeter, for example, when the component encounters temperature fluctuations and / or vibrations, the outer wall of the housing 1.21 and the first inner wall 3.11 of the clearance portion are designed accordingly.

[0042] Figure 5 Detailed diagram D shows the housing 1.21 and the main body 3. Figure 4 Accordingly, the tolerance sleeve 2 surrounding the housing 1.21 is arranged inside the recess 3.1 such that the tolerance sleeve is radially located between the first segment 1.211 and the fourth segment 3.114. Similarly, the tolerance sleeve 2 is radially located between the second segment 1.212 and the third segment 3.113. The tolerance sleeve 2 is radially clamped by the compressible or radially compressed reinforcing ribs 2.1. The housing 1.21 is designed such that a first conical surface 1.215 exists between the first segment 1.211 and the second segment 1.212. Furthermore, the main body 3 is constructed such that the first inner wall 3.11 between the third segment 3.113 and the fourth segment 3.114 has a second conical surface 3.115. In particular, the tolerance sleeve 2 is clamped between the first conical surface 1.215 and the second conical surface 3.115. This design improves the holding force, thereby effectively preventing significant displacement of the first component group 1.1 of the rotary encoder 1 relative to the second component group 1.2 due to temperature fluctuations or temperature differences within the components. Therefore, a constant scanning interval z can also be ensured.

Claims

1. An assembly comprising a rotary encoder (1), a tolerance sleeve (2), and a body (3) accommodating the rotary encoder and the tolerance sleeve (2), wherein The rotary encoder (1) has: A shaft (1.11) at which a scale element (1.12) is torsionally fixed, and A housing (1.21) in which a scanning unit (1.22) is arranged, the scanning unit being torsionally connected to the housing (1.21), wherein... The shaft (1.11) is rotatably arranged relative to the housing (1.21) about axis (A), and the scale element (1.12) can be scanned by the scanning unit (1.22). The housing (1.21) has an outer wall, the outer wall having a first distance (R1) to the axis (A) in a first section (1.211), and The outer wall has a second distance (r2) to the axis (A) in the second section (1.212), wherein, The first spacing (R1) is greater than the second spacing (r2), and The main body (3) has a void (3.1), wherein the void (3.1) is radially defined relative to the axis (A) by a first inner wall (3.11), wherein the first inner wall (3.11) has a third distance (r3) to the axis (A) in a third segment (3.113) and a fourth distance (R4) to the axis (A) in a fourth segment (3.114), wherein, The fourth spacing (R4) is greater than the third spacing (r3), and the void (3.1) is defined by a second inner wall (3.12), which forms an axial stop for the housing (1.21) relative to the axis (A), wherein the fourth segment (3.114) is arranged axially between the second inner wall (3.12) and the third segment (3.113), wherein, The tolerance sleeve (2) surrounds the housing (1.21) and is arranged within the clearance (3.1) such that the tolerance sleeve (2) is radially located between the first section (1.211) and the fourth section (3.114) and between the second section (1.212) and the third section (3.113) and is radially clamped.

2. The component according to claim 1, wherein, The second inner wall (3.12) forms an axial stop for the tolerance sleeve (2).

3. The component according to any one of the preceding claims, wherein, The housing (1.21) has a first conical surface (1.215) between the first section (1.211) and the second section (1.212).

4. The component according to any one of the preceding claims, wherein, The first inner wall (3.11) has a second conical surface (3.115) between the third segment (3.113) and the fourth segment (3.114).

5. The component according to any one of the preceding claims, wherein, The housing (1.21) has an annular outer wall.

6. The component according to any one of the preceding claims, wherein, The first inner wall (3.11) has an annular inner contour.

7. The component according to any one of the preceding claims, wherein, The rotary encoder (1) is designed as a bearingless rotary encoder (1).

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