Encoder

Abstract

The encoder according to an embodiment comprises: a shaft; a ring magnet connected to the shaft; a case accommodating at least a part of the shaft and the ring magnet; and a shielding member protruding from the case in a first direction perpendicular to the axial direction of the shaft.

Description

Encoder

[0001] The embodiment relates to an encoder.

[0002] Rotary encoders track the rotation and rotation of a motor shaft, generating digital information about its position and movement. Rotary encoders can be incremental, absolute, magnetic, or optical, and all perform the same function.

[0003] In particular, rotary magnetic encoders operate stably even in environments with severe shock or vibration or high temperatures, are resistant to external environments such as dust, and are small and inexpensive. Therefore, they are widely used in sophisticated and complex devices that require motion control, such as automobile anti-lock brake systems (ABS), industrial automation, medical equipment, and robots. In addition, types of rotary magnetic encoders include incremental, absolute, non-contact, bearing, and rotary types.

[0004] However, if magnetic debris enters or is located around a rotary magnetic encoder, it can cause performance degradation. Therefore, to prevent the influence of strong external magnetic fields, a case made of a material with a high magnetic permeability (over 4,000), called a shielding material, can be used to protect the sensor and magnet included in the rotary magnetic encoder. In this case, the shielding role can be faithfully performed, but additional components must be added to the encoder to perform functions other than shielding, such as connecting the encoder to other external structures, which can increase manufacturing costs and make the structure more complex.

[0005] In addition, even if the case is implemented with a shielding material, external magnetic fields can easily penetrate through the passage through which the connector connected to the encoder is introduced from the outside, interfering with the sensor located inside the encoder from accurately sensing the magnetic field, and research is being conducted on this.

[0006] The embodiment provides an encoder capable of accurately detecting a magnetic field.

[0007] An encoder according to an embodiment may include: a shaft; a ring magnet connected to the shaft; a case accommodating at least a portion of the shaft and the ring magnet; and a shielding member protruding from the case in a first direction orthogonal to an axial direction of the shaft.

[0008] For example, the encoder may further include a sensor positioned opposite the ring magnet; and a substrate on which the sensor is positioned and fixed in combination with the case.

[0009] For example, the shielding member may protrude from one side of the case in the first direction.

[0010] For example, the case may include an upper plate; a lower plate disposed below the upper plate; and a middle plate coupled with the upper plate and the lower plate to form a receiving hole for receiving at least a portion of the shaft, the ring magnet, and the sensor.

[0011] For example, the shielding member may include an upper shielding portion protruding in the first direction from one side of the upper plate; and a lower shielding portion protruding in the same direction as the direction in which the upper shielding portion protrudes from one side of the lower plate.

[0012] For example, a rotary magnetic encoder may further include a cable connected to the sensor, the case communicating with the outside, and including a connection opening through which the cable is introduced.

[0013] For example, the connecting opening and the shaft may face each other in a first direction, and each of the upper shield and the lower shield may face each other in a second direction with the shaft.

[0014] For example, the first direction and the second direction may be the same direction, or the first direction and the second direction may be orthogonal.

[0015] For example, at least a portion of each of the upper shield and the lower shield may have a rectangular shape.

[0016] For example, at least a portion of each of the upper shield and the lower shield may have a semicircular plate shape.

[0017] For example, the ring magnet may be positioned below the upper plate, the sensor may be positioned below the ring magnet, and the substrate may be positioned below the sensor and above the lower plate.

[0018] For example, the width of each of the upper shield and the lower shield in a second direction perpendicular to the first direction in which each of the upper shield and the lower shield protrudes may be 33% or more of the outer diameter of the upper plate.

[0019] For example, the length from the center of the shaft in the first direction to the end of at least one of the upper shield or the lower shield may be 91% or more of the outer diameter of the upper plate.

[0020] For example, the length when the first horizontal direction and the second horizontal direction are perpendicular to each other may be 120% to 195% of the length when the first horizontal direction and the second horizontal direction are the same.

[0021] For example, the width of the connecting opening in the second direction may be 25 to 100% of the width of at least one of the upper shield or the lower shield in the second direction.

[0022] For example, the height of the connecting opening in a third direction orthogonal to the first and second directions may be 57% to 95% of the width of at least one of the upper shield or the lower shield in the second direction.

[0023] A rotary magnetic encoder according to an embodiment is provided with a shielding member so that it is less affected by an external magnetic field, and thus can accurately detect the rotation angle of a shaft. In addition, the shielding member allows for easy connection to an external structure, thereby reducing manufacturing processes and costs.

[0024] Figure 1a shows a perspective view of an encoder according to one embodiment.

[0025] Figure 1b shows a plan view of the encoder illustrated in Figure 1a.

[0026] Figure 1c shows a cross-sectional side view of an encoder according to another embodiment.

[0027] Fig. 1d shows a right side view of an embodiment of the encoder illustrated in Fig. 1a as viewed from the right.

[0028] Figures 2a and 2b show a perspective view and a plan view, respectively, of an encoder according to another embodiment.

[0029] Figure 3 shows a perspective view of an encoder according to another embodiment.

[0030] Figure 4 is a three-dimensional graph showing the strength of the magnetic field according to the size of the shielding member.

[0031] Figure 5 is a graph showing the strength of the magnetic field according to the height of the connecting opening.

[0032] Fig. 6 shows a cross-sectional view of an encoder according to a comparative example.

[0033] Fig. 7 shows a cross-sectional view of an encoder according to another embodiment.

[0034] Figures 8a to 8d are diagrams showing the strength of the magnetic force at the entrance of the connection opening according to the position of the high-magnetic object.

[0035] Figures 9a and 9b are graphs showing the phase difference by outer diameter of the ring magnet.

[0036] Figures 10a and 10b are perspective views illustrating application examples of an encoder according to an embodiment.

[0037] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0038] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a second component may be referred to as a first component, and similarly, a first component may also be referred to as a second component. The term "and / or" includes a combination of a plurality of related described items or any of a plurality of related described items.

[0039] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0040] In the description of the embodiments, the description that each layer (film), region, pattern or structure is formed "on" or "under" the substrate, each layer (film), region, pad or pattern includes both being formed directly or through the interposition of another layer. The reference to "on" or "under" each layer is explained based on the drawings. In addition, the thickness or size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and therefore does not entirely reflect the actual size.

[0041] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0042] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0043] Hereinafter, embodiments will be described in detail with reference to the attached drawings. Regardless of the drawing symbols, identical or corresponding components will be given the same reference numbers and redundant descriptions thereof will be omitted.

[0044] Additionally, some embodiments are described using a Cartesian coordinate system (x-axis, y-axis, z-axis), and in the Cartesian coordinate system, the x-axis, y-axis, and z-axis depicted in each drawing are orthogonal to each other, but the embodiments are not limited thereto. The x-axis, y-axis, and z-axis may also intersect each other.

[0045] Hereinafter, a rotary magnetic encoder (hereinafter referred to as “encoder”) according to an embodiment is described with reference to the attached drawings.

[0046] FIG. 1a shows a perspective view of an encoder (100A) according to one embodiment, FIG. 1b shows a plan view of the encoder (100A) shown in FIG. 1a, FIG. 1c shows a side cross-sectional view of an encoder (100B) according to another embodiment, and FIG. 1d shows a right side view of the encoder (100A) shown in FIG. 1a according to the embodiment as viewed from the right side (i.e., in the -y-axis direction).

[0047] In one embodiment, the encoder (100A, 100B) includes a shaft (110), a ring magnet (120), a sensor (130), a shield linkage (150A, 150B) and a case (160A).

[0048] The shaft (110) can rotate in the direction of the arrow (A1). The shaft (110) can be implemented with a material having an investment rate close to 1, such as aluminum or plastic, but the embodiment is not limited thereto. Since the shaft (110) can be coupled with an object whose rotation angle is to be sensed by the encoder (100A, 100B), it can be implemented with a material that can have rigidity to maintain coupling with the object. The shaft (110) can have a shape that protrudes toward at least one of the upper and lower sides of the case (160A).

[0049] The ring magnet (120) can be coupled to the shaft (110) so as to be connected to and rotate together with the shaft (110). As the ring magnet (120) rotates together with the shaft (110), the intensity of the magnetic field measured by the sensor (130) can change. For example, the ring magnet (120) can be implemented with a general magnetic material having a magnetic permeability, such as a neodymium (Nd) magnet or ferrite.

[0050] The sensor (130) is positioned opposite to the ring magnet (120) and can sense a magnetic field that changes according to the rotation of the ring magnet (120).

[0051] According to an embodiment, the encoder (100A, 100B) may further include a substrate (140). The sensor (130) may be placed on the substrate (140), and the substrate (140) may be fixed by being coupled to the case (160A). Accordingly, even if the shaft (110) and the ring magnet (120) rotate, the substrate (140) and the sensor (130) placed on the substrate (140) may be fixed without rotating. In other words, even if the shaft (110) rotates, the substrate (140) may be placed so as to be fixed.

[0052] In FIG. 1c, the sensor (130) is illustrated as being positioned on the upper side of the substrate (140), but the embodiment is not limited to a specific shape in which the sensor (130) is positioned on the substrate (140).

[0053] The case (160A) can define a receiving hole (SP) that accommodates at least a portion of the shaft (110), a ring magnet (120), and a sensor (130).

[0054] The shielding members (150A, 150B) may be arranged to protrude from the case (160A) in a horizontal direction. According to an embodiment, the shielding members (150A, 150B) may protrude from one side of the case (160A) in the y-axis direction, which is a horizontal direction. That is, the shielding members (150A, 150B) may protrude from the case (160A) in the y-axis direction, which is a direction orthogonal to the z-axis direction, which is an axial direction of the shaft (110).

[0055] The shielding member (150A, 150B) arranged in this manner can suppress an external magnetic field from entering the interior of the encoder (100A, 100B), suppress a magnetic field from leaking from the interior of the encoder (100A, 100B) to the exterior, and serve as a bridge so that the encoder (100A, 100B) can be easily coupled to an external structure. This will be described later with reference to FIGS. 10A and 10B.

[0056] According to an embodiment, the shielding member (150A) may be implemented with a magnetic material having an investment permeability of 4,000 to 5,000, for example, carbon steel such as S45C or SPCC, but is not limited thereto. If the shielding member (150A, 150B) is implemented with a material having a high investment permeability exceeding 5,000, there may be concerns about magnetic field absorption.

[0057] Referring to FIG. 1c, the ring magnet (120) may be placed under the upper plate (UP), the sensor (130) may be placed under the ring magnet (120), and the substrate (140) may be placed under the sensor (130) and above the lower plate (LP).

[0058] Meanwhile, the case (160A) may include an upper plate (UP), a middle plate (CPA), and a lower plate (LP). The upper plate (UP) may be positioned on the upper side of the case (160A), and the lower plate (LP) may be positioned below the case (160A), i.e., below the upper plate (UP). The middle plate (CPA) may be combined with the upper plate (UP) and the lower plate (LP), respectively, to form a receiving hole (SP).

[0059] According to an embodiment, the shielding member (150A, 150B) may include an upper shielding portion (152A, 152B) and a lower shielding portion (154A, 154B).

[0060] According to one embodiment, as illustrated in FIGS. 1A, 1B, and 1D, the upper shielding portion (152A) may be disposed to protrude in the y-axis direction, which is a horizontal direction, from one side of the upper plate (UP), and the lower shielding portion (154A) may be disposed to protrude in the y-axis direction, which is the same direction as the direction in which the upper shielding portion (152A) protrudes from one side of the lower plate (LP). That is, the upper shielding portion (152A) and the lower shielding portion (154A) may be disposed to protrude in the same direction. In this way, according to one embodiment, the upper plate (UP) and the upper shielding portion (152A) may be disposed on the same horizontal plane, and the lower plate (LP) and the lower shielding portion (154A) may be disposed on the same horizontal plane.

[0061] In another embodiment, as illustrated in FIG. 1C, the upper shield (152B) may include a first portion (P1) positioned above the case (160A), i.e., above the upper plate (UP), and a second portion (P2) protruding in the horizontal y-axis direction from the first portion (P1). The lower shield (154B) may include a third portion (P3) positioned below the case (160A), i.e., below the lower plate (LP), and a fourth portion (P4) protruding in the horizontal y-axis direction from the third portion (P3).

[0062] In FIG. 1a, FIG. 1b, and FIG. 1d, the upper shielding portion (152A) and the lower shielding portion (154A) can serve as shields, and in FIG. 1c, the second and fourth portions (P2, P4) can serve as shields.

[0063] As described above, except for the different shapes of the shielding members (150A, 150B), the encoders (100A, 100B) have the same configuration. Therefore, except for the shapes of the shielding members (150A, 150B), FIG. 1C may correspond to a cross-sectional view of the encoder (100A) illustrated in FIG. 1B taken along line A-A'.

[0064] In addition, FIGS. 1a, 1b and 1d may correspond to a case where the first part (P1) and the upper plate (UP) shown in FIG. 1c are integral, and the third part (P3) and the lower plate (LP) are integral.

[0065] The encoder (100A, 100B) according to the embodiment may further include a cable (not shown) connected to the sensor (130) and a control unit (not shown) connected to the cable.

[0066] A change in the magnetic field sensed by the sensor (130) can be transmitted to an externally arranged control unit (not shown) via a cable (not shown), and a driving current for driving the sensor (130) required for the sensor (130) to detect a change in the magnetic field can be provided to the sensor (130) via a cable from the outside of the encoder (100A, 100B). For this purpose, the case (160A) may further include a connection opening (OP).

[0067] The connection opening (OP) serves to connect the inside and outside of the case (160A) and may have a shape through which a cable can be inserted.

[0068] Figures 2a and 2b show a perspective view and a plan view, respectively, of an encoder (100C) according to another embodiment.

[0069] Figure 3 shows a perspective view of an encoder (100D) according to another embodiment.

[0070] In one embodiment, at least a portion of the upper shield (152A, 152B) may have a rectangular planar shape and at least a portion of the lower shield (154A, 154B) may have a rectangular bottom shape, as illustrated in FIGS. 1A to 1D and FIG. 3.

[0071] In another embodiment, as illustrated in FIGS. 2A and 2B , at least a portion of the upper shield (152C) may have a semicircular plate-shaped planar shape. At least a portion of each of the lower shields (154C) may have a semicircular plate-shaped bottom surface shape.

[0072] In this way, except that the planar and bottom shapes of the upper shields (152A, 152B, 152C) and the lower shields (154A, 154B, 154C) are different from each other, the encoder (100C) illustrated in FIGS. 2A and 2B is the same as the encoder (100A, 100B) illustrated in FIGS. 1A to 1D, and therefore, a duplicate description is omitted.

[0073] Hereinafter, the direction in which the connection opening (OP) and the shaft (110) face each other is referred to as the 'first horizontal direction', and the direction in which the upper shielding portions (152A, 152B, 152C) and the lower shielding portions (154A, 154B, 154C) face each other with the shaft (110) is referred to as the 'second horizontal direction'.

[0074] In one embodiment, as illustrated in FIG. 1A or FIG. 2A, the first horizontal direction and the second horizontal direction may be the same direction. That is, the connection opening (OP) and the shaft (110) may face each other in the first horizontal direction, which is the y-axis direction, and the upper shielding portions (152A, 152C) and the lower shielding portions (154A, 154C) may face the shaft (110) in the second horizontal direction, which is the y-axis direction.

[0075] In another embodiment, as illustrated in FIG. 3, the first horizontal direction and the second horizontal direction may be different from each other. For example, the first horizontal direction and the second horizontal direction may be orthogonal. That is, the connection opening (OP) and the shaft (110) may face each other in the first horizontal direction, which is the x-axis direction, while each of the upper shields (152A, 152C) and the lower shields (154A, 154C) may face each other in the y-axis direction with respect to the shaft (110). That is, the position at which the connection opening (OP) is arranged in the middle plate (CPA) illustrated in FIG. 1A is different from the position at which the connection opening (OP) is arranged in the middle plate (CPB) illustrated in FIG. 3.

[0076] Hereinafter, the sizes of each of the shielding member (150A, 150B) and the connection opening (OP) according to the embodiment are described as follows.

[0077] Figure 4 is a three-dimensional graph showing the strength of the magnetic field (Mag B) according to the size (X1, Y1) of the shielding member (150A, 150B, 150C). Here, X1 and Y1 will be described later.

[0078] Referring to Fig. 1b, the width (X1) of each of the upper shielding portion (152A) and the lower shielding portion (154A) in the second direction (i.e., the x-axis direction) perpendicular to the first direction (i.e., the y-axis direction) in which each of the upper shielding portions (152A) and the lower shielding portion (154A) protrudes is referred to as a “first width.” At this time, the first width (X1) may be 30% or more of the outer diameter (OD1) of the upper plate (UP) (hereinafter, referred to as the “first outer diameter”).

[0079] The length (Y1) from the center (PO) of the shaft (110) in the first direction (i.e., the y-axis direction) to the end of at least one of the upper shield (152A) or the lower shield (154A) is referred to as the 'first length'. At this time, the first length (Y1) may be 90% or more of the first outer diameter (OD1) of the upper plate (UP). For example, the first width (X1) may be 3 mm to 5 mm, preferably 4 mm or more, and the first length (Y1) may be 9 mm to 13 mm, preferably 11 mm or more. In addition, when the encoder (100C) is implemented as shown in FIGS. 2A and 2B, the size of the first length (Y1) may further increase. For example, the first length (Y2) shown in FIGS. 2A and 2B may be 12.9 mm.

[0080] Although not illustrated, the first portion (P1) illustrated in FIG. 1c has the same planar shape as the upper plate (UP) illustrated in FIG. 1b, and the second portion (P2) has the same planar shape as the upper shield (152A) illustrated in FIG. 1b. In addition, the third portion (P3) illustrated in FIG. 1c may have the same bottom shape as the lower plate (LP) illustrated in FIG. 1b, and the fourth portion (P4) may have the same bottom shape as the lower shield (152A) illustrated in FIG. 1b.

[0081] In the case of Fig. 1c, the width of each of the upper shielding portion (152B) and the lower shielding portion (154B) in the second direction (i.e., x-axis direction) orthogonal to the first direction (i.e., y-axis direction) in which each of the upper shielding portion (152B) and the lower shielding portion (154B) protrudes is referred to as a “second width.” At this time, the second width may be 30% or more of the first outer diameter (OD1) of the upper plate (UP). The length from the center (PO) of the shaft (110) in the first direction (i.e., y-axis direction) to the end of at least one of the second portion (P2) or the fourth portion (P4) is referred to as a “second length.” At this time, the second length may be 90% or more of the outer diameter of the first or third portion (P1, P3).

[0082] In addition, as shown in FIG. 3, the first length (Y1) (or second length) when the first horizontal direction and the second horizontal direction are perpendicular to each other may be 120% to 195% of the first length (Y1) (or second length) when the first horizontal direction and the second horizontal direction are the same as shown in FIG. 1A and FIG. 2A, for example, 14.4 mm to 23.4 mm.

[0083] Fig. 5 is a graph showing the intensity of the magnetic field (Mag B) according to the height of the connection opening (OP), where the horizontal axis represents the height of the connection opening (OP) and the vertical axis represents the magnitude of the magnetic field flowing into the connection opening (OP). Accordingly, 'K' represents the intensity of the magnetic field flowing into the connection opening (OP) according to the height of the connection opening (OP). At this time, the maximum value of the magnetic field that the sensor (130) can sense is 6 mT.

[0084] According to an embodiment, the width (X2) (hereinafter referred to as “third width”) in the second direction (i.e., x-axis direction) of the connection opening (OP) illustrated in FIGS. 1A, 2A, and 2B may be 25 to 100% of the first width (X1) in the second direction (i.e., x-axis direction) of at least one of the upper shielding portion (152A) and the lower shielding portion (154A). For example, the third width (X2) may be 1 mm to 4 mm.

[0085] According to an embodiment, in the case of the encoder (100B) illustrated in FIG. 1C, the third width (X2) in the second direction (i.e., in the x-axis direction) of the connection opening (OP) may be 25 to 100% of the first width (X1) in the second direction (i.e., in the x-axis direction) of at least one of the second and fourth portions (P2, P4). For example, the third width (X2) may be 1 mm to 4 mm.

[0086] Additionally, the height (Z) in the third direction (i.e., the z-axis direction) orthogonal to the first and second directions of the connection opening (OP) illustrated in FIGS. 1A, 2A, 2B, and 3 may be 57% to 95% of the first width (X1) in the second direction (i.e., the x-axis direction) of at least one of the upper shielding portions (152A, 152C) or the lower shielding portions (154A, 154C). For example, the height (Z) may be 2.3 mm to 3.8 mm.

[0087] For FIG. 1c, the height (Z) of the connecting opening (OP) may be 57% to 95% of the first width (X1) of at least one of the second or fourth portions (P2, P4).

[0088] Hereinafter, encoders according to comparative examples and embodiments are described with reference to the attached drawings.

[0089] Fig. 6 shows a cross-sectional view of an encoder according to a comparative example, and Fig. 7 shows a cross-sectional view of an encoder (100E) according to another embodiment. In Figs. 6 and 7, the illustration of the sensor is omitted.

[0090] Fig. 7 corresponds to a case where the lower plate (LP) and the third and fourth parts (P3, P4) of the encoder (100B) illustrated in Fig. 1c are implemented as the lower plate (LP) and the lower shielding part as illustrated in Fig. 1d, and therefore, redundant description is omitted.

[0091] The encoder according to the comparative example illustrated in FIG. 6 includes a shaft (10), a ring magnet (20), a substrate (40), and a case (60). The shaft (10), the ring magnet (20), the substrate (40), and the case (60) perform the same roles as the shaft (110), the ring magnet (120), the substrate (140), and the case (160A) according to the embodiment, respectively, and therefore, a duplicate description is omitted.

[0092] The encoder according to the comparative example does not include a shielding member as in the embodiment. Therefore, as illustrated in FIG. 6, the magnetic field distributed toward the connection opening (OP) penetrates into the interior of the encoder and affects the magnetic field inside the encoder, so that the sensor cannot accurately sense the magnetic field changed by the rotation of the ring magnet (20).

[0093] On the other hand, referring to FIG. 7, in the case of the embodiment, as the upper shielding portion (152B) and the lower shielding portion (154A) of the shielding member (150B) absorb the external magnetic field, the magnetic field intensity of the area flowing into the connection opening (OP) may be reduced compared to FIG. 6.

[0094] Figures 8a to 8d are drawings showing the intensity of the magnetic force (hereinafter referred to as “first intensity”) at the entrance of the connection opening (OP) according to the position of the high-magnetic object (300).

[0095] As shown in FIG. 8a, when the high-magnetic object (300) is placed on the opposite side of the connection opening (OP), the first intensity is 5.45 mT, as shown in FIG. 8b, when the high-magnetic object (300) is placed facing the connection opening (OP), the first intensity is 2.37 mT, as shown in FIG. 8c, when the high-magnetic object (300) is placed below the encoder (100E), the first intensity is 5.14 mT, and as shown in FIG. 8d, when the high-magnetic object (300) is placed above the encoder (100E), the first intensity is 5.01 mT.

[0096] In the comparative example illustrated in Fig. 6, the magnetic strength (hereinafter referred to as "second strength") at the entrance of the connecting opening (OP) is measured to be 24.5 mT. Therefore, it can be seen that the first strength is reduced by 77.8% to 79.6% compared to the second strength.

[0097] Figures 9a and 9b are graphs showing the phase difference according to the outer diameter (OD2) (hereinafter referred to as “second outer diameter”) of the ring magnet (120), where the horizontal axis represents the angle at which the shaft (110) rotates, and the vertical axis represents the magnetic field (or magnetic force).

[0098] If the strength of the magnetic force in the vertical z-axis direction is less than the minimum value of the magnetic force that the sensor (130) can sense, for example, if the second outer diameter (OD2) is less than 58% or greater than 75% of the first outer diameter (OD1), a phase difference (PD1) error greater than or less than 180° may occur each time the shaft (110) is rotated 180°, as shown in FIG. 9a.

[0099] On the other hand, if the strength of the magnetic force in the vertical z-axis direction is greater than the minimum value of the magnetic force that the sensor (130) can sense, for example, if the second outer diameter (OD2) is 58% to 75% of the first outer diameter (OD1), a phase difference (PD2) of 180° occurs whenever the shaft (110) is rotated 180° as shown in FIG. 9b, so that no phase difference error occurs. For example, if the minimum value of the magnetic field that the sensor (130) can sense is 160 mT, the second outer diameter (OD2) may be 6.4 mm to 8.2 mm, but the embodiment is not limited thereto.

[0100] The encoders (100A to 100E) according to the aforementioned embodiments can perform sensing tasks in countless applications. For example, the encoders (100A to 100E) can be used in all equipment related to automation, as well as devices using motors and drives. For example, the encoders (100A to 100E) can be used for speed control in home appliances, elevators, and conveyor belts, and for position control in automation equipment, industrial equipment, and robots.

[0101] Figures 10a and 10b are perspective views illustrating application examples of an encoder according to an embodiment.

[0102] The encoders illustrated in FIGS. 10a and 10b are identical to the encoder illustrated in FIG. 1a, and therefore, the same reference numerals are used and redundant descriptions are omitted.

[0103] As shown in FIGS. 10A and 10B, the shaft (110) of the encoder can be coupled with the first object (500) to measure the rotation angle of the first object (500) in the arrow direction (A2).

[0104] At this time, the shielding member (150A) of the encoder can be used to couple with another second object (400). For example, the shielding member (150A) illustrated in FIG. 10a is inserted into the hollow (400P) of the second object (400) as illustrated in FIG. 10b, thereby allowing the encoder to couple with the second object (400).

[0105] In order to couple the encoder according to the comparative example illustrated in Fig. 6 to the second object (400), a separate member must be installed in the case (60).

[0106] On the other hand, according to the embodiment, a shielding member (150A) can be used to couple the encoder to the second object (400), so that a separate member is not required, thereby reducing material costs and simplifying the manufacturing process.

[0107] Although the above has been described focusing on embodiments, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present embodiment. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

[0108] The mode for carrying out the invention has been sufficiently described in the above-mentioned “Best mode for carrying out the invention.”

[0109] The rotary magnetic encoder according to the embodiment can be widely used in sophisticated and complex devices requiring motion control operations, such as anti-lock brake systems (ABS) of automobiles, industrial automation, medical equipment, and robots.

Claims

1. Shaft; A ring magnet connected to the above shaft; a case accommodating at least a portion of the shaft and the ring magnet; and An encoder including a shielding member protruding from the case in a first direction orthogonal to the axial direction of the shaft.

2. In paragraph 1, A sensor positioned opposite the above ring magnet; and An encoder further comprising a substrate in which the above sensor is arranged and fixed in combination with the case.

3. In the first paragraph, the shielding member An encoder protruding from one side of the case in the first direction.

4. In paragraph 2, The above case is top plate; a lower plate arranged on the lower side of the upper plate; and An encoder comprising a middle plate coupled to the upper plate and the lower plate to form a receiving hole for receiving at least a portion of the shaft, the ring magnet, and the sensor.

5. In paragraph 4, The above shielding member An upper shield protruding in the first direction from one side of the upper plate; and An encoder including a lower shield portion protruding in the same direction as the upper shield portion protruding from one side of the lower plate.

6. In paragraph 5, Further comprising a cable connected to the above sensor, An encoder wherein the case communicates with the outside and includes a connection opening through which the cable is introduced.

7. In paragraph 6, The above connecting opening and the above shaft are opposite to each other in the first direction, An encoder in which each of the upper shield and the lower shield faces the shaft in the second direction.

8. In paragraph 7, An encoder in which the first direction and the second direction are the same direction.

9. In paragraph 7, An encoder in which the first direction and the second direction are orthogonal.

10. An encoder in accordance with claim 5, wherein at least a portion of each of the upper shield and the lower shield has a rectangular shape.

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