Patent ID: 12188543

MODES FOR CARRYING OUT THE INVENTION

The speed reducer-equipped motor10according to an embodiment of this disclosure will be described below with reference toFIGS.1to4.

In the drawings, the Z-direction, as denoted by the arrow Z, represents one of opposite axial directions of the pinion gear30C working as an output gear. The R-direction, as denoted by the arrow R, represents an outward one of opposite radial directions of the pinion gear30C. The C-direction, as denoted by the arrow C, represents one of opposite circumferential directions of the pinon gear30C. A direction opposite the Z-direction will also be referred to as a second axial direction of the pinion gear30C. A direction opposite the R-direction will also be referred to as an inward or second radial direction of the pinion gear30C. A direction opposite the C-direction will also be referred to as a second circumferential direction of the pinion gear30C. Unless otherwise specified, an axial direction, a radial direction, and a circumferential direction, as simply referred to below, represent an axial direction, a radial direction, and a circumferential direction of the pinion gear30C.

The speed reducer-equipped motor10illustrated inFIGS.1,2, and3is designed as a power seat motor working to move the bottom of a car seat in an upward or downward direction. The speed reducer-equipped motor10includes the motor12implemented by a dc motor. The speed reducer-equipped motor10also includes the speed reducer14which reduces the speed of rotation of the rotating shaft12A of the motor12and transmits it to the output gear unit30serving as an output member of the speed reducer14. The speed reducer-equipped motor10further includes the housing16to which the motor12is secured and in which the speed reducer14is disposed.

The speed reducer14includes the worm gear18, the helical gear20, and the eccentric shaft22. The worm gear18is firmly secured to the rotating shaft12A of the motor12. The helical gear20works as a first gear meshing with the worm gear18. The eccentric shaft22is mounted integrally in the helical gear20.

The speed reducer14also includes the transmission gear24, the lock gear26, and the stationary gear28. The transmission gear24and the lock gear26are retained by the eccentric shaft22. The stationary gear28meshes with the lock gear26. The speed reducer14also includes the slider plate52which is retained by the stationary gear28and works as a rotation stopper. The rotation of the transmission gear24is stopped by meshing the transmission gear24with the slider plate52. The speed reducer14also includes the output gear unit30which meshes with the transmission gear24and is equipped with the pinion gear30C. The output gear unit30has an axis which is oriented in the same direction as those of the helical gear20, the transmission gear24, and the lock gear26, in other words, extends in the Z-direction and a direction opposite the Z-direction. The axis of the output gear unit30is arranged in alignment with that of the helical gear20.

The speed reducer-equipped motor10also includes the spring32which minimizes the backlash or lost motion of the eccentric shaft22and the helical gear20in the axial direction thereof. The speed reducer-equipped motor10also includes the cover plate34which is fixed to the housing16to accommodate the speed reducer14within the housing16.

The housing16illustrated inFIGS.1and2is made from resin material. The housing16is equipped with the motor retaining portion16A by which the motor12is firmly retained with the rotating shaft12A extending in a direction perpendicular to the Z-direction. The housing16has formed therein the reducer-housing recess16C in which the speed reducer14is accommodated. The reducer-housing recess16C is of a concave shape with an opening end facing in the axial direction (i.e., the Z-direction).

The reducer-housing recess16C, as clearly illustrated inFIG.1, includes a bottom wall and the side wall16E. The bottom wall defines a bottom of the reducer-housing recess16C. The side wall16E extends from an outer circumference of the bottom wall in the axial direction and has a cylindrical inner peripheral surface. The reducer-housing recess16C has a hollow cylindrical boss, which will be described later, into which an end (which will also be referred to as a second end) of the rotation center shaft40which faces in the second axial direction is inserted with a clearance between itself and the boss. The spring32is arranged around the boss on the bottom wall. The washer36is disposed between the bottom wall and the spring32.

The side wall16E of the reducer-housing recess16C formed on an inner periphery thereof three stationary gear engagement portions16G which a portion of the stationary gear28, as will be described later in detail, engages to stop the stationary gear28from rotating in the circumferential direction thereof. Each of the stationary gear engagement portions16G includes the cylindrical pole161.

The cover plate34is made of a steel plate. The cover plate34has formed therein the exposure opening34A through which the pinion gear30C is exposed outside the reducer-housing recess16C of the housing16. The cover plate34has a peripheral edge which defines the outline of the exposure opening34A and is bent toward the first axial direction (i.e., the Z-direction) to form the annular rib34B.

The worm gear18has a spiral tooth formed on an outer periphery thereof. The motor12mounted on the rotating shaft12A is secured to the housing16, thereby placing the worm gear18within the housing16and close to the bottom and the inner peripheral surface of the reducer-housing recess16C.

The helical gear20illustrated inFIGS.1and2is made from resin material. The helical gear20has formed on the outer periphery thereof a plurality of external teeth meshing with the helical tooth of the worm gear18. The eccentric shaft22is secured into the axial center of the helical gear20using insert-molding techniques. The helical gear20is rotatably retained by the housing16through the eccentric shaft22and the rotation center shaft40.

The eccentric shaft22illustrated inFIGS.2and3is made of metallic material and has a portion inserted into the helical gear20so that it rotates along with the helical gear20. Specifically, the eccentric shaft22has the disc22A which has a thickness in the axial direction and extends in the radial direction thereof. The disc22A has formed on an outer circumference thereof protrusions which are arranged adjacent each other in the circumferential direction. The disc22A is firmly fit in the inner periphery of the helical gear20with the center axis thereof coinciding with the center of rotation of the helical gear20.

The eccentric shaft22is, as clearly illustrated inFIGS.1and3, equipped with the support22B which protrudes from the center of the disc22A in the first axial direction (i.e., the Z-direction). The support22B has a first end and a second end which is opposed to the first end and faces in the second axial direction. The first end of the support22B defines the first supporting portion22B1by which the transmission gear24is, as will be described later in detail, retained to be rotatable. The second end of the support22B defines the second supporting portion22B2which is larger in diameter than the first supporting portion22B1and by which the lock gear26is, as will be described later in detail, retained to be rotatable. The first supporting portion22B1is oriented to have the axial center offset from that of the disc22A in the outer radial direction (i.e., the R-direction). The second supporting portion22132is oriented to have the axial center offset from that of the disc22A in the outer radial direction.

The eccentric shaft22, as illustrated inFIGS.2,3, and4, has formed therein the axial center through-hole22C extending through the disc22A, the first supporting portion2261, and the second supporting portion22132in the axial direction thereof. The axial center through-hole22C has the rotation center shaft40inserted thereinto. The axial center of the axial center through-hole22C (i.e., the axial center of the rotation center shaft40inserted into the axial center through-hole22C) coincides with that of the disc22A.

The output gear unit30illustrated inFIGS.2and4is made from metallic material. The output gear unit30, as can be seen inFIG.2, includes the transmission gear-engaging portion30B which engages the transmission gear24. The transmission gear-engaging portion30B has the recessed housing30E which opens to the transmission gear24(i.e., the second axial direction) in which the transmission gear body24D of the transmission gear24is disposed. The recessed housing30E has formed in an inner surface of a peripheral portion thereof the internal teeth30F meshing with the external teeth24A of the transmission gear24.

The output gear unit30also includes the pinion gear30C which is arranged on one of axially opposed sides of the transmission gear-engaging portion30B and axially aligned with the transmission gear-engaging portion30B. The pinion gear30C has a plurality of external teeth formed on an outer periphery thereof. The output gear unit30has an intermediate portion which is located between the transmission gear-engaging portion30B and the pinion gear30C and defines the axially-supported portion30D which is supported by the rib34B of the cover plate34. The rib34B has firmly fit in an inner periphery thereof the bearing bush42made from resin material. This avoids or minimizes a risk that the axially-supported portion30D of the output gear unit30and the rib34B of the cover plate34may experience metal-contact with each other. The output gear unit30has the rotation center shaft40press-fit in the axial center thereof. The rotation center shaft40is of a bar shape made from metallic material.

The stationary gear28is produced by pressing metallic material. The stationary gear28is, as illustrated inFIGS.1and2, equipped with the stationary gear body28A of an annular shape, as viewed in the axial direction. The stationary gear28is equipped with three fitting protrusions28B which extend radially outwardly from the stationary gear body28A. When the fitting protrusions28B are fit on the stationary gear engagement portions16G of the housing6, a push nut, not shown, is fit on the cylindrical poles161, thereby achieving securement of the stationary gear28to the housing16.

The stationary gear body28A has formed in an inner periphery thereof a plurality of internal teeth28D which mesh with the lock gear26which will be described later in detail.

The stationary gear28is also equipped with the second stopper28E which protrudes from the stationary gear body28A in the second axial direction (which is opposite to the Z-direction). Specifically, the second stopper28E protrudes in the second axial direction from a portion of the circumference of the stationary gear body28A.

The stationary gear body28A of the stationary gear28has the slider plate-fitting hole28F formed in a first one of walls thereof opposed to each other in the axial direction. The first wall of the stationary gear body28A has the internal teeth28D formed therein. The slider plate-fitting hole28F is shaped to have a rectangular outline, as viewed in the axial direction. The slider plate52is disposed inside the slider plate-fitting hole28F. The slider plate52has a pair of first slider surfaces52C which will be described later in detail. The slider plate-fitting hole28F has the second slider surfaces28G which are defined by inner opposed edges of the slider plate52and face each other in the radial direction of the slider plate52. The slider plate52is disposed in the slider-plate fitting hole27F with each of the first slider surfaces52C facing one of the second slider surfaces28G of the slider plate-fitting hole28F. The first slider surfaces52C and the second slider surfaces28G are placed to face each other to stop the slider plate52from rotating relative to the stationary gear28. The first slider surfaces52C are slidable on the second slider surfaces28G to permit the slider plate52and the transmission gear24to move in the radial direction R1 that is an outward radial direction of the stationary gear28. This causes the transmission gear24to revolve around the axial center of the rotation center shaft40following rotation of the eccentric shaft22while stopping the transmission gear24mounted on the first supporting portion22B1of the eccentric shaft22from rotating around the axis thereof.

The transmission gear24is, as illustrated inFIGS.1,2,3, and4, produced by pressing a metallic material into a circular shape. The transmission gear24includes the transmission gear body24D which has the external teeth24A formed on the outer circumference thereof. The transmission gear body24D has formed in the center thereof the fitting hole24B which fits on the first supporting portion22B1of the eccentric shaft22. The transmission gear24has two stopper protrusions24E which extend from an end surface of the transmission gear body24D which faces in the second axial direction. The stopper protrusions24E are arranged at an angular interval of 180° away from each other in the circumferential direction of the transmission gear24. The stopper protrusions24E engages the slider plate52, as will be described later in detail, to stop the eccentric shaft22of the transmission gear24from rotating around the first supporting portion22B1of the eccentric shaft22(i.e., around the center axis of the eccentric shaft22).

The slider plate52illustrated inFIGS.1and3is made of a metallic plate and of a rectangular shape, as viewed in the axial direction. The slider plate52is arranged between the two stopper protrusions24E of the transmission gear24within the slider plate-fitting hole28F of the stationary gear28. The slider plate52has the engaging surfaces52B on the circumference thereof. Each of the engaging surfaces52B faces a respective one of the stopper protrusions24E in the radial direction. In the condition where the slider plate52is placed between the stopper protrusions24E of the transmission gear24, the stopper protrusions24E work to stop the transmission gear24from moving relative to the slider plate52in a direction (i.e., the radial direction R1) in which the engaging surfaces52B and the stopper protrusions24E face each other and also stop the transmission gear24from rotating relative to the slider plate52(i.e., around the center of the transmission gear24). The stopper protrusions24E are slidable on the engaging surfaces52B, thereby permitting the transmission gear24to move relative to the slider plate52in a direction in which the engaging surfaces52B and the stopper protrusions24E slide on each other in the second radial direction R2 perpendicular to the radial direction R1. The outer periphery of the slider plate52has the pair of first slider surfaces52C which faces the second slider surfaces28G of the slider plate-fitting hole28F and are arranged close to the slider surfaces28G. The slider plate52has formed in the center thereof the elongated hole52A into which the first supporting portion22B1of the eccentric shaft22is inserted. The elongated hole52A is shaped to have a length extending in the second radial direction R2. The interval or distance between the engaging surfaces52B of the slider plate52is selected to be smaller than that between the first slider surfaces52C. The engaging surfaces52B, therefore, define long opposite sides of the rectangular shape of the slider plate52, while the first slider surfaces52C define short opposite sides of the rectangular shape of the slider plate52.

The lock gear26is, like the transmission gear24, as illustrated inFIGS.1and2, made by pressing a metallic material into a disc shape. The lock gear26has formed on the whole of an outer periphery thereof external teeth26A meshing with the internal teeth28D of the stationary gear28. The lock gear26has formed in the center thereof the fitting hole26B which is fit on the second supporting portion2262of the eccentric shaft22. The lock gear26also includes the first stopper26C which extends radially outwardly and has a fan-shape, as viewed in the axial direction. The first stopper26C is formed on a portion of the circumference of the lock gear26. In a condition where the external teeth26A of the lock gear26mesh with the internal teeth28D of the stationary gear28, the first stopper26C is located over one of major opposite surfaces of the stationary gear body28A of the stationary gear28which faces in the second axial direction.

Operation and Advantageous Effect of this Embodiment

The operation of and advantageous effects offered by this embodiment will be described below.

In the speed reducer-equipped motor10illustrated inFIGS.1and2, when the rotating shaft12A of the motor12starts to rotate, it will cause the worm gear18to rotate. The rotation of the worm gear18causes the helical gear20which meshes with the worm gear18to rotate along with the eccentric shaft22.

The rotation of the eccentric shaft22causes the center of the transmission gear24mounted on the first supporting portion22B1of the eccentric shaft22to revolve around the center of the rotation center shaft40. Specifically, referring toFIG.5, when the eccentric shaft22rotates, the stopper protrusions24E of the transmission gear24slide on the engaging surfaces52B of the slider plate52and move in the radial direction (i.e., opposite to the direction R2). The first slider surfaces52C of the slider plate52also slides on the second slider surfaces28G of the stationary gear28, so that the slider plate52and the transmission gear24are moved in the radial direction (i.e., opposite the direction R1). This causes the center of the transmission gear24to revolve around the center of the rotation center shaft40while holding the transmission gear24mounted on the first supporting portion22B1of the eccentric shaft22from rotating around the center axis thereof

The revolution of the transmission gear24, as illustrated inFIGS.1and2, causes torque produced by such revolution to be transmitted from the external teeth24A of the transmission gear24to the output gear unit30through the internal teeth30F of the output gear unit30. This causes the output gear unit30to rotate, thereby actuating the power seat of the vehicle through a gear meshing with the pinion gear30C of the output gear unit30.

The rotation of the eccentric shaft22causes the lock gear26which is mounted on the second supporting portion22132of the eccentric shaft22and meshes with the stationary gear28to revolute around the center of the rotation center shaft40and also rotates around the center axis thereof. When the first stopper26C of the lock gear26contacts with the second stopper28E of the stationary gear28, it stops both the rotation and the revolution of the lock gear26. This holds the eccentric shaft22and the helical gear20from rotating, thereby stopping the rotation of the output gear unit30. This avoids or minimizes input of undesirable excessive torque from the speed reducer-equipped motor10to the power seat of the vehicle.

The speed reducer14which constitutes a portion of the structure of the speed reducer-equipped motor10is, as described above, designed as a planetary gear speed reducer. It is, therefore, preferable that a gear which is required to stop its rotation is selected depending upon a speed reduction ratio which the speed reducer14is required to have. Specifically, the speed reducer14may be implemented by 2K-H planetary gear mechanism, a 3K planetary gear mechanism, a solar speed reducer, or a star speed reducer depending upon a speed reduction ratio required for the speed reducer14.

Structure Ensuring Stability of Contact Between Slider Plate60and Stopper Protrusion24E of Transmission Gear24

The structure or mechanism for ensuring the stability in contact between the slider plate60and the stopper protrusions24E of the transmission gear24will be described below in detail. First, the structure of the slider plate62and deformation of the stopper protrusions24E which may occur in a speed reducer-equipped motor including the slider plate62will be discussed below. Subsequently, the structure of the slider plate60in this embodiment configured to minimize the deformation of the stopper protrusions24E which would occur in the speed reducer-equipped motor including the slider plate62in the comparative example will be described.

FIG.6illustrates the structure of the slider plate62in the comparative example which is nearly identical with that of the above-described slider plate52. The same parts of the slider plate62as those of the slider plate52are denoted by the same reference numbers, and explanation thereof in detail will be omitted here.

The slider plate62in the comparative example, as clearly illustrated inFIGS.6and7, has one (which will also be referred to below as a first surface) of major surfaces opposed to each other in the thickness direction which faces the transmission gear body24D of the transmission gear24. The first surface has the corners64which are rounded or chambered in a C-shape and will also be referred to below as chamfered corners62A. The chamfered corners62A are shaped to have dimensions selected to avoid mechanical interference of the corners64with the rounded corner24F of each of the stopper protrusions24E which leads to a major part of the transmission gear body24D, in other words, located at a base end of the stopper protrusion24E which is closer to the transmission gear body24D in a condition where the stopper protrusions24E are placed in physical contact with the engaging surface52B of the slider plate62.

When the pressure of contact between each of the stopper protrusions24E and a corresponding one of the engaging surfaces52B of the slider plate62rises, it may cause, as demonstrated inFIG.8, the slider plate62to be undesirably forced against the stopper protrusions24E along the chamfered corners62A and deform portions of the stopper protrusions24E. In the following discussion, the deformed portions of the stopper protrusions24E will also be referred to below as the deformed portions24G. With this condition, the continuous use of the speed reducer-equipped motor including the slider plate62will cause, as demonstrated inFIG.9, the slider plate62to be further forced against the stopper protrusions24E along the chamfered corners62A, thus resulting in excessive deformation of the stopper protrusions24E, in other words, an increase in volume of the deformed portions24G. In this way, the state of contact between the slider plate62and the stopper protrusions24E of the transmission gear24changes, thereby resulting in instability of contact of the slider plate62with the stopper protrusions24E.

In order to alleviate the above adverse event, the speed reducer-equipped motor10includes the slider plate60which works as a rotation stopper and is, as illustrated inFIGS.10and11, equipped with four interference avoidance protrusions60A which work as an interference avoider and extend toward the transmission gear body24D of the transmission gear24(i.e., the first axial direction). The interference avoidance protrusions60A are formed integrally with the slider plate60at the same time as when the slider plate60is forged. The interference avoidance protrusions60A are located on four corners of the slider plate60, as viewed in the first axial direction. The slider plate60also has four recesses60B formed in the surface thereof facing in the second axial direction. Specifically, the recesses60B are formed in portions of the surface of the slider plate60which are aligned, one with each of the interference avoidance protrusions60A in the axial direction. The same reference numbers of other parts of the slider plate60as employed for the slider plate52indicate the same or similar parts, and explanation thereof in detail will be omitted here.

Each of the interference avoidance protrusions60A has a head end surface60C which is flat contacting with the second surface of the transmission gear body24D which faces in the second axial direction. Each of the interference avoidance protrusions60A has a dimension H in a direction in which the interference avoidance portions60A protrude in the axial direction is selected to eliminate a risk that the corners64of the slider plate60which face the transmission gear body24D of the transmission gear24may physically interfere with the rounded corners24F of the stopper protrusions24E when the head end surfaces60C of the interference avoidance protrusions60A is in physical contact with the second axial surface of the transmission gear body24D of the transmission gear24, and when the stopper protrusions24E is in physical contact with the engaging surfaces52B of the slider plate60.

An area of each of the engaging surfaces52B of the slider plate60on which a corresponding one of the stopper protrusions24E slides is defined as a sliding region60D. The slider plate60in this disclosure is designed to have the four interference avoidance protrusions60A offset outside the sliding regions60D, as viewed facing the engaging surfaces52B in the radial direction. Specifically, two of the interference avoidance protrusions60A arranged close to a respective one of the engaging surfaces52B are located outside, in other words, offset from a corresponding one of the sliding regions60D in the radial direction R1 and a second radial direction which is opposite the radial direction R1, respectively. The corners64of the slider plate60which face the transmission gear body24D of the transmission gear24are also shaped not to have chamfered surfaces, such as the chamfered corners62A of the slider plate62.

The use of the above-described slider plate60with the speed reducer-equipped motor10causes all the interference avoidance protrusions60A of the slider plate60to physically contact with the second axial surface of the transmission gear body24D of the transmission gear24which face in the second axial direction. This eliminates the risk that the corners64of the slider plate60which face the transmission gear body24D of the transmission gear24may physically interfere with the rounded corners24F of the stopper protrusions24E when the speed reducer-equipped motor10is operating. The corners64of the slider plate60are, as described above, shaped not to have chamfered surfaces, such as the chamfered corners62A of the slider plate62in the comparative example. The use of the above structure of the slider plate60with the speed reducer-equipped motor10, therefore, minimizes or eliminates the risk that the corners64of the slider plate60may be forced against the stopper protrusions24E to cause the undesirable deformation of the stopper protrusions24E when the speed reducer-equipped motor10is operating. This ensures the stability of physical contact of the slider plate60with the stopper protrusions24E of the transmission gear24.

The interference avoidance protrusions60A are, as described above, all formed integrally with the slider plate60, thereby enabling the number of parts of the speed reducer-equipped motor10to be decreased. The structure of the slider plate60also eliminates the need for machining the corners64to have chamfered surfaces, such as the chamfered corners62A of the slider plate62in the comparative example.

The slider plate60, as described above, has the four interference avoidance protrusions60A formed on the four corners of the surface thereof facing in the first axial direction (i.e., the Z-direction). This avoids undesirable tilting of the slider plate60relative to the transmission gear24when all the interference avoidance protrusions60A contact with the second axial surface of the transmission gear body24D of the transmission gear24.

The slider plate60, as described above, has the interference avoidance protrusions60A offset outside the sliding regions60D, as viewed facing the engaging surfaces52B in the radial direction, thereby eliminating the risk of interference of the corners64of the slider plate60with the rounded corners24F of the stopper protrusions24E regardless of a positional relation between the stopper protrusions24E of the transmission gear24and the slider plate60.

Speed Reducer-Equipped Motor in the Second Embodiment

A speed reducer-equipped motor in the second embodiment will be described below with reference toFIGS.12and13.

A speed reducer-equipped motor according to the second embodiment is, as illustrated inFIGS.12and13, equipped with the transmission gear24and the slider plate52which are identical in structure with those of the above-described speed reducer-equipped motor10. The speed reducer-equipped motor in this embodiment also includes the washer66which works as an interference avoider disposed between the transmission gear24and the slider plate52. The washer66is shaped to have an outer diameter smaller than an interval between the engaging surfaces52B of the slider plate52. The washer66also has an inner diameter which is greater than an inner diameter of the fitting hole24B of the transmission gear24and substantially identical with a length of the short axis of the ellipse through-hole52A of the slider plate52. The washer66has a thickness which is selected to achieve no physical interference between the corners64of the slider plate52close to the transmission gear body24D of the transmission gear24and the rounded corners24F of the bottoms of the stopper protrusions24E in conditions where the washer66is gripped between the transmission gear24and the slider plate52, and the stopper protrusions24E is in contact with the engaging surfaces52B of the slider plate60.

The speed reducer-equipped motor in the second embodiment, like the speed reducer-equipped motor with the above-described slider plate60, works to ensure the stability in contact between the slider plate52and the stopper protrusions24E of the transmission gear24.

Speed Reducer-Equipped Motor in the Third Embodiment

A speed reducer-equipped motor according to the third embodiment will be described below withFIG.14.

The speed reducer-equipped motor in the third embodiment, as illustrated inFIG.14, includes the transmission gear24and the slider plate52which are substantially identical in structure with those of the speed reducer-equipped motor10. The speed reducer-equipped motor in this embodiment includes a plurality of spherical members68which are disposed between the transmission gear24and the slider plate52and work as interference avoiders. Specifically, the speed reducer-equipped motor includes four spherical members68in the form of balls. The slider plate52has four fitting recesses70which are formed in four corners of the slider plate52, as viewed in the axial direction thereof, and in each of which a respective one of the spherical members68is partially fit.

The distance by which each of the spherical members68extends outside the slider plate52is selected to achieve no physical interference between the corners64of the slider plate52close to the transmission gear body24D of the transmission gear24and the rounded corners24F of the bottoms of the stopper protrusions24E in conditions where the spherical members68are in contact with the surface (i.e., the bottom) of the transmission gear body24D of the transmission gear24which faces in the second axial direction, and the stopper protrusions24E is in contact with the engaging surfaces52B of the slider plate60.

The speed reducer-equipped motor in the third embodiment, like the speed reducer-equipped motor with the above-described slider plate60, works to ensure the stability in contact between the slider plate52and the stopper protrusions24E of the transmission gear24.

The embodiments of this disclosure have been described above, but however, this disclosure is not limited to the above statements. The disclosure should be understood to include all possible embodiments and modifications to the shown embodiments which can be embodied without departing from the principle of the disclosure.

This disclosure is not limited to the above embodiments, but may be realized by various embodiments without departing from the purpose of the disclosure. This disclosure includes all possible combinations of the features of the above embodiments or features similar to the parts of the above embodiments. The structures in this disclosure may include only one or some of the features discussed in the above embodiments unless otherwise inconsistent with the aspects of this disclosure.