STATOR FOR A ROTATING DEVICE

Abstract

A limited-slip differential stator includes an inner lip that fits into a central opening. The inner lip engages with a bearing ring to secure the stator to a gearbox housing of the limited-slip differential. The stator holds an electromagnetic coil. The stator is shaped to avoid any constrictions in the electromagnetic flux that could limit the electromagnetic force exerted on a locking mechanism of the limited-slip differential.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] This application, filed on April 22, 2024, as an international PCT application, claims the benefit and priority of the preliminary US application No. 63 / 497,506 filed on April 21, 2023, the disclosure of which is hereby incorporated in its entirety by reference into this application. BACKGROUND

[0002] Traction-modifying limited-slip differentials typically comprise a gearbox housing defining a gear chamber, and arranged therein a differential gear comprising at least one input pinion and a pair of output side gears. Typically, such a "limited-slip differential" includes some type of locking mechanism to prevent rotation of one of the side gears relative to the gearbox housing, the engagement of which is triggered by some type of actuating device. By transmitting a suitable input signal to an electromagnetic coil, a locking element engages a matching section connected to the arranged side gear of the differential. The electromagnetic coil is held by a stator located outside the gearbox housing. In certain embodiments, a bearing ring holds the stator to the gearbox housing.

[0003] With reference to Fig. Figure 9 shows an outer circumference 150 of an exemplary bearing ring 162 radially supporting a stator 160, which holds an electromagnetic coil 116, to position the stator 160 on a gearbox housing. The bearing ring 162 is fastened to the gearbox housing (e.g., using a snap ring). The bearing ring 162 includes a finger 152 that projects radially outward from the outer circumference 150. The stator 160 defines a notch 154 on an axially outer side 132. In certain embodiments, the notch 154 is located at a radially inner corner of the stator 160. The finger 152 of the bearing ring 162 extends into the notch 154 to hold the stator 160 axially relative to the gearbox housing.

[0004] The magnetic flux density is mapped across the stator 160, the bearing ring 162, and a section 120 of an actuating mechanism for the locking element. When the electromagnetic coil 116 is energized, the notch 154 forms a constriction for the magnetic force flowing through the stator 160. For example, the region of the stator 160 extending between the electromagnetic coil 116 and the notch 154 exhibits a magnetic flux density that is higher than the magnetic flux density of the remainder of the stator 160. The magnetic flux limits the magnetic force that can be exerted between the stator 160 and the section 120 of the actuating mechanism, thereby limiting the braking force of the locking differential 100.

[0005] Improvements are desirable. SUMMARY

[0006] According to certain aspects of the disclosure, a rotary device comprises a stator that is axially movable relative to a rotatable housing. A bearing ring limits the path of the stator by engaging an inner lip defined by the stator.

[0007] According to certain aspects of the disclosure, a rotary device comprises a stator with an electromagnet that actuates a locking mechanism of the rotary device. The shape of the stator limits the magnetic flux density of the stator to less than 2 Tesla.

[0008] In certain embodiments, the stator defines a central opening extending between opposing first and second sides of the stator. The stator includes a section extending radially into the central opening to define an inner lip.

[0009] In certain embodiments, the thickness of the stator does not decrease from the outer radial end of the stator to the inner radial end of the stator.

[0010] The following description sets out various additional inventive aspects. These inventive aspects may relate to individual features or combinations of features. It is understood that both the preceding general description and the following detailed description are merely exemplary and illustrative and do not limit the broad inventive concepts on which the embodiments disclosed herein are based. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are part of the description, illustrate various aspects of the present revelation. The drawings can be briefly described as follows: Fig. Figure 1 is a cross-sectional view of an example of a locking differential configured according to the principles of the present disclosure. Fig. Figure 2 is a perspective view of an exemplary stator designed for use with the locking differential made of Fig. 1 is suitable. Fig. Figure 3 is an opposing perspective view of the stator from Fig. 2; Fig. Figure 4 is a cross-sectional view of the stator made of Fig. 2; Fig. 5 is an enlarged view of a section of Fig. 5; Fig. Figure 6 is an enlarged view of a section of Fig. 2, wherein the stator is arranged in a first position in which an electromagnetic coil is not excited; Fig. Figure 7 is an enlarged view of a section of Fig. 2, wherein the stator is arranged in a second position in which an electromagnetic coil is excited. Fig. Figure 8 is a representation of the electromagnetic flux density across the stator from the Fig. 1-7; and Fig. Figure 9 is a representation of the electromagnetic flux density across a conventional stator. DETAILED DESCRIPTION

[0012] The following section discusses in detail exemplary aspects of the present disclosure, which are illustrated in the accompanying drawings. Where possible, the same reference numerals are used throughout the drawings to indicate identical or similar parts.

[0013] A 100 locking differential for a vehicle that is in the Fig. 1 and Fig. The assembly shown in Figure 10 comprises a gearbox housing 102 (e.g., a gearbox housing and an end cap) configured to rotate about a longitudinal axis L of the housing 102. The torque for the locking differential 100 can be transmitted via an input ring (not shown) to a flange 105 of the gearbox housing 102. The gearbox housing 102 defines annular hub sections 106 and 108 to which a left and right axle shaft are coupled. A pair of bearing sets (not shown) arranged on the annular hub sections 106 and 108 provide a rotating mount for the rotating differential device 100 relative to an outer differential housing or "carrier" (also not shown). The rotatable housing 102 defines a gearbox chamber in which a differential gear 110 is arranged.

[0014] The locking differential 100 can be operated in a locked mode or an unlocked mode. In locked mode, one or both side gears 126, 128 of the differential 110 are locked against rotation relative to the gearbox housing 102. In unlocked mode, the side gears 126, 128 can rotate freely relative to the gearbox housing 102. For example, the side gears 126, 128 can be configured to rotate independently of each other about the longitudinal axis L of the gearbox housing 102. In some embodiments, the locking differential 100 is manually switched between locked and unlocked modes by a user. In other embodiments, the locking differential 100 is automatically switched between locked and unlocked modes (e.g., by a vehicle microprocessor based on a detected operating state of the vehicle).

[0015] The locking differential 100 includes a locking assembly 118 that can be switched between a locked and an unlocked configuration. In the locked configuration, the locking assembly 118 prevents independent rotation of the side gear 126 relative to the gearbox housing 102. In the unlocked configuration, the locking assembly 118 allows independent rotation of the side gear 126 relative to the gearbox housing 102.

[0016] In certain embodiments, the locking assembly 118 is arranged within the gearbox housing 102. The locking assembly 118 comprises a generally annular collar element 122 having tabs projecting outwards from its circumference. When the locking assembly 118 is in the locked configuration, each of the tabs engages in a corresponding axially extending recess defined by the gearbox housing 102. The tabs prevent rotation of the collar element 122 relative to the gearbox housing 102 but allow axial movement of the collar element 122 between a locked position and an unlocked position. A preloading element 124 (e.g., one or more wave springs) biases the collar element 122 towards the unlocked position.

[0017] The locking arrangement 118 also includes an actuating mechanism for switching the locking arrangement 118 between the locked and unlocked configurations. The actuating mechanism comprises actuating elements (e.g., pins) that extend outward from fixed positions on the collar element 122 and through the gearbox housing 102. The actuating elements extend to a ramp plate 120 on an opposite side of the gearbox housing 102. In certain embodiments, the ramp plate 120 is located outside the gearbox housing 102. The ramp plate 120 defines a plurality of ramp surfaces—one ramp surface 121 for each actuating element (see, for example, Figure 1). Fig. 11) When the actuating elements are arranged on the undersides of the ramp surfaces 121, the preload element 124 pushes the collar element 122 into the unlocked position. When the ramp plate 120 rotates relative to the actuating elements, the actuating elements slide up the ramp surfaces 121 and thereby push the collar element 120 axially into the locked position against the preload of the spring 124.

[0018] The rotation of the ramp plate 120 relative to the actuating elements is controlled by an electromagnet 116 arranged on a stator 104. In certain embodiments, the ramp plate 120 is made of an iron metal. When the electromagnet 116 is not energized (i.e., not actuated), the actuating elements drive the ramp plate 120 to rotate with the gearbox housing 102. When the electromagnet 116 is energized (i.e., actuated), it slows the rotation of the ramp plate 120 relative to the gearbox housing 102. This slowed rotation of the ramp plate 120 causes the actuating elements to slide up the ramp surfaces 121 and move the collar element 122 into the locked position. In certain embodiments, the electromagnetic coil 116 can be energized by a pair of electrical leads (not shown).

[0019] Further details regarding the operation of the actuating mechanism of the locking differential 100 of the type described above are set forth in US patents Nos. 6,083,134, 6,551,209 and 7,264,569, the disclosures of which are hereby incorporated into this description by reference.

[0020] As in the Fig. 1 and Fig. As shown in Figure 10, the stator 104, which holds the electromagnet 116, is attached to the housing 102 by means of a bearing ring 112. The bearing ring 112 is mounted in an axially fixed position on the gearbox housing 102. For example, the bearing ring 112 can be axially fixed to the gearbox housing 102 by means of a snap ring 114. Other configurations are possible. A contact surface 144 of the bearing ring 112 is aligned with an inner lip 140 of the stator 104 about the longitudinal axis L. In certain embodiments, the stator 104 is configured such that it can be moved axially along the longitudinal axis L between a first position (e.g., see Figure 10). Fig. 6) and a second position (e.g. see Fig. 7) moves, depending on whether the coil 116 is energized. The contact between the inner lip 140 of the stator 104 and the contact surface 144 of the bearing ring 112 defines the first position. The contact between a first axial side of the stator 104 and the ramp plate 120 defines the second position.

[0021] The Fig. Figures 2-5 show an example of the design of a stator 104, which is for use in the locking differential 100. Fig. 1 is suitable. The stator 104 comprises a body 130 extending between a first axial side 132 and a second axial side 134. The second axial side 134 defines a cavity (e.g., an annular cavity) 142 in which the coil 116 can be arranged. The body 130 defines a central opening 136 extending between the first and second axial sides 132, 134. The central opening 136 allows the stator body 130 to be mounted around a section of the housing 102 (see, e.g., Fig. 1).

[0022] According to certain aspects of the disclosure, the stator 104 comprises a constricted section 138 that reduces the size of the central opening 136 on the second axial side 134 of the stator body 130. The constricted section 138 defines an inner lip 140 that is accessible within the central opening 136. In certain embodiments, the constricted section 138 is located on the second axial side 134 of the stator body 130. In certain examples, the constricted section 138 is flush with the second axial side 134 of the stator body 104. In certain embodiments, the constricted section 138 extends over less than half the axial length of the stator body 130. In certain embodiments, the constricted section 138 extends over no more than one-quarter of the axial length of the stator body 130.

[0023] In certain embodiments, the central opening 136 of the stator body 130 has a first inner diameter ID1 at the first axial side 132 of the body 130 and a second inner diameter ID2 at the second axial side 134 of the body 130. In certain embodiments, the second inner diameter ID2 is smaller than the first inner diameter ID1. The constricted section 138 defines the second inner diameter ID2. In some embodiments, the first inner diameter ID1 is constant between the inner lip 140 and the first axial side 132 of the stator body 130. In other embodiments, the first inner diameter ID1 can vary between the inner lip 140 and the first axial side 132, but always remains larger than the second inner diameter ID2. In certain embodiments, the second inner diameter ID2 is constant across the constricted section 138.

[0024] In certain embodiments, the stator body 130 has a U-shaped cross-section (see, for example, Figure 1). Fig. 5) The cavity 142 is defined in a central part of the U, while the bottom of the U forms the first axial side 132 of the stator body 130. In certain embodiments, a radially outer corner 146 of the U-shaped cross-section is contoured, while a radially inner corner 148 of the U-shaped cross-section is angled. In some embodiments, the radially inner corner 148 has a right-angled corner. In other embodiments, the radially inner corner 148 is chamfered. In certain embodiments, the radially inner corner 148 is thicker than the radially outer corner 146.

[0025] The stator body 130 has a thickness T (see e.g. Fig. 5) The thickness T2 at the radially inner section of the U-shaped cross-section is not less than the thickness T1 at the radially outer section of the U-shaped cross-section. In certain examples, the thickness T2 is greater than the thickness T1. In certain examples, the thickness T of the stator body 130 does not decrease as the stator body 130 extends from the radially outer section to the radially inner section.

[0026] Fig. Figure 8 shows the magnetic flux density of stator 104, which is configured according to the principles of this disclosure. As shown, stator 104 does not define a notch (e.g., notch 154 of stator 160). Fig.9) to form a constriction for the electromagnetic flux. Rather, the thickness T of the stator body 130 either remains constant or increases as the body extends radially inward and then toward the ramp plate 120. By eliminating the constriction, the electromagnetic force that can be exerted by the coil 116 on the ramp plate 120 is increased. In certain examples, an increase in this force can help to counteract the angular momentum of the ramp plate 120 more quickly and / or effectively. In certain examples, an increase in this force allows for an increase in the preload of the spring 124, which can extend the service life of the locking differential 100.

[0027] Having described the preferred aspects and embodiments of the present disclosure, a person skilled in the art could easily conceive of modifications and equivalents of the disclosed concepts. However, it is intended that such modifications and equivalents are included within the scope of the claims set forth herein. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 497,506

[0001] US 6,083,134

[0019] US 6,551,209

[0019] US 7,264,569

[0019]

Claims

[1] Rotary device comprising: a rotating housing; a stator with an annular housing arranged around a section of the rotatable housing, wherein the stator defines a central opening through which a section of the rotatable housing extends when the stator is coupled to the rotatable housing, and wherein the stator has an inner lip extending radially from a radially inwardly directed circumference of the stator into the central opening; and a bearing ring which is mounted at a fixed position around the section of the rotatable housing, wherein the bearing ring is dimensioned to fit into the central opening of the stator such that an outer circumference of the bearing ring is opposite the radially inward circumference of the stator, wherein the inner lip of the stator extends radially inward beyond the outer circumference of the bearing ring. [2] Rotary device according to claim 1, wherein a contact surface of the bearing ring is arranged radially within the outer circumference of the bearing ring, wherein the contact surface is aligned with the inner lip of the stator. [3] Rotary device according to claim 1, wherein the bearing ring has a constant outer diameter. [4] Rotating device according to claim 1, wherein the bearing ring has no outwardly projecting lips. [5] Rotating device according to claim 1, wherein the inner lip is arranged on an axial side of the stator. [6] Rotating device according to claim 2, which further comprises an electromagnet arranged on the stator. [7] Rotating device according to claim 6, wherein the stator is configured such that, when the electromagnet is activated, it moves axially relative to the housing from a first position to a second position, wherein the inner lip of the stator is in contact with the bearing ring in the first position and the inner lip of the stator is spaced away from the bearing ring in the second position. [8] Rotating device according to claim 7, wherein the stator is pre-tensioned in the first position. [9] Rotating device according to claim 8, further comprising a locking arrangement arranged around the rotatable housing, wherein the locking arrangement is configured to switch between a locked configuration and an unlocked configuration, wherein the locking arrangement prevents the housing from rotating relative to the stator when it is in the locked configuration, wherein the locking arrangement allows rotation of the housing relative to the stator when it is in the unlocked configuration, wherein the locking arrangement selectively switches between the locked and the unlocked configuration based on the activation of the electromagnet, wherein the stator is biased into the first position via the locking arrangement. [10] Rotating device according to claim 6, wherein the stator defines an annular cavity in which the electromagnet is arranged. [11] Rotating device according to claim 1, wherein the thickness of the stator does not decrease from an outer radial end of the stator to an inner radial end of the stator. [12] Rotary device comprising: a rotating housing; a stator with an annular housing arranged around a section of the rotatable housing, wherein the stator defines a central opening through which a section of the rotatable housing extends when the stator is coupled to the rotatable housing; and a bearing ring that is mounted at a fixed position around the section of the rotatable housing, wherein the bearing ring is dimensioned to fit into the central opening of the stator such that an outer circumference of the bearing ring faces a radially inward circumference of the stator, wherein a thickness of the stator does not decrease as the stator extends radially inward in the direction of the outer circumference of the bearing ring. [13] Rotary device according to claim 12, wherein an axial engagement between the bearing ring and the stator is located radially within the outer circumference of the bearing ring. [14] Rotary device according to claim 12, wherein the bearing ring has a constant outer diameter. [15] Rotating device according to claim 12, wherein the bearing ring has no outwardly projecting lips. [16] Rotating device according to claim 12, wherein the entire stator has a magnetic flux density of less than 2 Tesla. [17] Rotating device according to claim 12, wherein the first side of the stator does not have concave surfaces. [18] Rotating device according to claim 12, wherein a diameter of the central opening on the second side of the stator is smaller than a diameter of the central opening on the first side of the stator. [19] Rotary device comprising: a rotating housing; a stator with an annular housing arranged around a section of the rotatable housing, wherein the stator defines a central opening through which a section of the rotatable housing extends when the stator is coupled to the rotatable housing, the central opening extending between opposite first and second sides of the stator, the stator comprising a section extending radially into the central opening on the second side to define an inner lip; a bearing ring which is fitted at a fixed position around the section of the rotatable housing, wherein the bearing ring is dimensioned to fit into the central opening of the stator such that a contact surface of the bearing ring is opposite the inner lip of the stator to hold the stator to the rotatable housing. [20] Rotating device according to claim 19, wherein the rotatable housing comprises a differential housing.

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