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Title:
LOW PROFILE FRACTIONAL HORSEPOWER DC BRUSH MOTOR
Document Type and Number:
WIPO Patent Application WO/2018/111646
Kind Code:
A1
Abstract:
A low-profile DC brush motor has a disk shaped commutator and a disk shaped lamination stack. The lamination stack has a diameter and a height with a diameter to height ratio in the range of (6.0 - 8.0) to 1. The disk shaped commutator has a diameter and a height with a diameter to height ratio in the range of (10.0 - 15.0) to 1. A ratio of the diameter of the commutator to the diameter of the lamination stack is in the range of (0.5 - 1.0) to 1.0. In an aspect, a food waste disposer has a motor section that includes the low-profile DC brush motor.

Inventors:
STRUTZ, William (3728 Wyoming Way, Racine, Wisconsin, 53404, US)
FARAGO, Charles (8555 32nd Ave, Kenosha, Wisconsin, 53142, US)
Application Number:
US2017/064888
Publication Date:
June 21, 2018
Filing Date:
December 06, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
EMERSON ELECTRIC CO. (8000 West Florissant Ave, St. Louis, Missouri, 63136, US)
International Classes:
H02K23/40; H02K13/00; H02K23/04
Foreign References:
JP2015220865A2015-12-07
US20060082234A12006-04-20
US8053945B22011-11-08
US6198195B12001-03-06
Other References:
None
Attorney, Agent or Firm:
FULLER, III, Roland A., et al. (Harness, Dickey & Pierce P.L.C.,P.O. Box 82, Bloomfield Hills Michigan, 48303, US)
Download PDF:
Claims:
What is claimed is:

1 . A food waste disposer, comprising:

a food conveying section, a motor section and a grind and discharge section disposed between the food conveying section and the motor section, the grind and discharge section having a grind section and a discharge section;

the grind section including a grind mechanism with a stationary grind ring and a rotating shredder plate assembly, the rotating shredder plate assembly including a rotatable shredder plate having lugs, the grind section including a grind housing that encompasses the grind mechanism and holds the stationary grind ring;

the motor section including a low-profile DC brush motor, the low-profile DC brush motor including:

a frame supporting a stator;

an armature having a disk shaped lamination stack with coil windings and the lamination stack affixed to an armature shaft that extends through the lamination stack, the lamination stack having a diameter and a height with a diameter to height ratio in the range of (6.0 - 8.0) to 1 ;

a disk shaped commutator affixed to the armature shaft having radially outwardly facing brush contact surfaces that are contacted in a radial direction by brushes of the motor that are held in brush holders of the motor, the commutator having a diameter and a height with a diameter to height ratio in the range of (10.0 - 15.0) to 1 ; and

a ratio of the diameter of the commutator to the diameter of the lamination stack is in the range of (0.5 - 1 .0) to 1 .0.

2. The food waste disposer of claim 1 wherein a wherein the diameter of the lamination stack of the armature of the motor is in the range of 4.0 inches to 6.0 inches.

3. The food waste disposer of claim 1 wherein the motor has a rated power of up to one horsepower, the commutator of the motor has a diameter of 3.0 inches and a height of 0.25 inches, and the lamination stack of the armature of the motor has a diameter of 5.0 inches and a height of 0.75 inches.

4. The food waste disposer of claim 1 wherein the motor wherein the motor is a permanent magnet DC brush motor having a permanent magnet stator. 5. The food waste disposer of claim 1 wherein the motor is a universal motor having a wound stator.

6. A low-profile DC brush motor, comprising:

a frame supporting a stator;

an armature having a disk shaped lamination stack with coil windings and the lamination stack affixed to an armature shaft that extends through the lamination stack, the lamination stack having a diameter and a height with a diameter to height ratio in the range of (6.0 - 8.0) to 1 ;

a disk shaped commutator affixed to the armature shaft having radially outwardly facing brush contact surfaces that are contacted in a radial direction by brushes of the motor that are held in brush holders of the motor, the commutator having a diameter and a height with a diameter to height ratio in the range of (10.0 - 15.0) to 1 ; and

a ratio of the diameter of the commutator to the diameter of the lamination stack is in the range of (0.5 - 1 .0) to 1 .0.

7. The motor of claim 6 wherein the diameter of the lamination stack is in the range of 4.0 inches to 6.0 inches.

8. The motor of claim 7 wherein the motor has a rated power of up to one horsepower, the commutator has a diameter of 3.0 inches and a height of 0.25 inches, and the lamination stack has a diameter of 5.0 inches and a height of 0.75 inches.

9. The motor of claim 7 wherein the motor is a permanent magnet DC brush motor having a permanent magnet stator.

10. The motor of claim 7 wherein the motor is a universal motor having a wound stator.

1 1. The motor of claim 7 and further including a food waste disposer having a motor section that includes the motor.

AMENDED CLAIMS

received by the International Bureau on 1 1 May 2018 (1 1.05.2018)

1 . A food waste disposer, comprising:

a food conveying section, a motor section and a grind and discharge section disposed between the food conveying section and the motor section, the grind and discharge section having a grind section and a discharge section;

the grind section including a grind mechanism with a stationary grind ring and a rotating shredder plate assembly, the rotating shredder plate assembly including a rotatable shredder plate having lugs, the grind section including a grind housing that encompasses the grind mechanism and holds the stationary grind ring;

the motor section including a low-profile DC brush motor, the low-profile DC brush motor including:

a frame supporting a stator;

an armature having a disk shaped lamination stack with coil windings and the lamination stack affixed to an armature shaft that extends through the lamination stack, the lamination stack having a diameter and a height with a diameter to height ratio in the range of (6.0 - 8.0) to 1 ;

a disk shaped commutator affixed to the armature shaft having radially outwardly facing brush contact surfaces that are contacted in a radial direction by brushes of the motor that are held in brush holders of the motor, the commutator having a diameter and a height with a diameter to height ratio in the range of (10.0 - 15.0) to 1 ; and

a ratio of the diameter of the commutator to the diameter of the lamination stack is in the range of (0.5 - 1 .0) to 1 .0.

2. The food waste disposer of claim 1 wherein a wherein the diameter of the lamination stack of the armature of the motor is in the range of 4.0 inches to 6.0 inches.

3. The food waste disposer of claim 1 wherein the motor has a rated power of up to one horsepower, the commutator of the motor has a diameter of 3.0 inches and a height of 0.25 inches, and the lamination stack of the armature of the motor has a diameter of 5.0 inches and a height of 0.75 inches.

4. The food waste disposer of claim 1 wherein the motor wherein the motor is a permanent magnet DC brush motor having a permanent magnet stator. 5. The food waste disposer of claim 1 wherein the motor is a universal motor having a wound stator.

6. A low-profile DC brush motor, comprising:

a frame supporting a stator;

an armature having a disk shaped lamination stack with coil windings and the lamination stack affixed to an armature shaft that extends through the lamination stack, the lamination stack having a diameter and a height with a diameter to height ratio in the range of (6.0 - 8.0) to 1 ;

a disk shaped commutator affixed to the armature shaft having radially outwardly facing brush contact surfaces that are contacted in a radial direction by brushes of the motor that are held in brush holders of the motor, the commutator having a diameter and a height with a diameter to height ratio in the range of (10.0 - 15.0) to 1 ; and

a ratio of the diameter of the commutator to the diameter of the lamination stack is in the range of (0.5 - 1 .0) to 1 .0.

7. The motor of claim 6 wherein the diameter of the lamination stack is in the range of 4.0 inches to 6.0 inches. 8. The motor of claim 7 wherein the motor has a rated power of up to one horsepower, the commutator has a diameter of 3.0 inches and a height of

0.25 inches, and the lamination stack has a diameter of 5.0 inches and a height of 0.75 inches.

9. The motor of claim 6 wherein the motor is a permanent magnet DC brush motor having a permanent magnet stator.

10. The motor of claim 6 wherein the motor is a universal motor having a wound stator. 1 1 . The motor of claim 6 and further including a food waste disposer having a motor section that includes the motor.

Description:
LOW PROFILE FRACTIONAL HORSEPOWER DC BRUSH MOTOR

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 62/432,898 filed on December 12, 2016. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to a low-profile fractional horsepower direct current ("DC") brush motor.

BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] A fractional horsepower DC brush motor as that term is commonly used in the art is a DC motor that has a rated power of one horsepower or less, often less than one horsepower. Rated power as is understood in the art and as used herein is a measure of how much work the motor can do without overheating. More specifically, it's the maximum horsepower that the motor can provide under normal, continuous operation or for a specified period under specified conditions. In the case of a food waste disposer, this period would typically be no more than twenty minutes. The rated horsepower is based on the motor's full-load torque and full-load speed, and is calculated as the product of full-load speed and full-load torque. The rated power is defined under rated motor input voltage and frequency conditions.

[0005] The DC brush motor has a wound armature having a lamination stack with coil windings wound in slots in the lamination stack and either a wound stator having coil windings wound in slots in a yoke of the stator or a permanent magnet stator having a plurality of permanent magnet pole sets. A permanent magnet pole set is a pair of permanent magnets that are mounted to an inner surface of a housing of the stator on opposed sides of the stator so that they are on opposed sides of the armature. They are oriented with opposite magnetic polarity so that a north pole of one permanent magnet faces radially inwardly toward the armature and a south pole of the other permanent magnet faces radially inwardly toward the armature. The armature has a shaft extending through a center of the lamination stack. A barrel shaped commutator is mounted on the armature shaft and has a plurality of conductive segments connected to ends of the coil windings of the armature. The number of conductive commutator segments is typically the same as the number of spaces (slots) in the lamination and the number of coils. Preferably, a prime number (3, 7, 1 1 , 13, 17, etc.) of segments, spaces and coils are used for optimal motor performance. However, any number may be used with a potential increase in switching spikes and noise. The number of commutator segments and coils may be increased by a factor of 2 or 4 to accommodate voltages 2 or 4 times 120 volts while keeping the number of lamination slots and the number of magnet poles the same as a design for 120 volts. Outer surfaces of the conductive segments face radially outwardly and provide radially outward facing brush contact surfaces for contact by brushes of the motor. The brushes are connected to a DC power source and provide DC power to the armature via the commutator. Many have a bridge rectifier to run directly from a typical household circuit with 120 volts AC and capable of handling 15 or 20 amps of current. In some cases, the bridge rectifier is part of the motor and in other cases it is separate from the motor.

[0006] Conventional fractional horsepower DC brush motors typically have a small diameter armature where the lamination stack of the armature has a 0.5 inch to 2.0 inch outer diameter and the motor has a radial air gap of approximately 0.040 inch between the outer diameter of the lamination stack of the armature and an inner diameter of the stator (whether wound or permanent magnet stator). These motors typically have a commutator that has a diameter that is about 60 percent of the diameter of the lamination stack of the armature and 0.5 to 1 .0 inches long. The brushes, typically two, are held in brush holders on opposed sides of the commutator and extend radially to the commutator and are urged against the outer surface of the commutator, typically by spring force. The brush holders are supported by a frame structure of the motor that also supports the stator and has a bearing or bushing in which the armature shaft is entrained. While some such motors have one bearing or bushing on one side of the lamination stack, other such motors have a bearing or bushing on each side of the laminations stack. Many have a bridge rectifier to run directly from a typical household circuit with 120 volts AC and capable of handling 15 or 20 amps of current. In some cases, the bridge rectifier is part of the motor and in other cases it is separate from the motor.

[0007] Another type of DC motor, known as a disc armature motor, has a printed circuit (disc) armature which is less than 0.2 inches thick and the brushes commutate directly on the windings of the armature in an axial direction. This type of motor typically has a lower height profile in the axial direction than does the above described conventional fractional horsepower DC brush motor. The printed circuit (disc) motor is not capable of handling the high stall currents that the conventional fractional horsepower DC brush motor can handle. Due to the small mass of the armature of the disc motor, disc motors have a tendency to overheat easily. Typically, a controller must be used to limit the amount of voltage and current and time at locked rotor or at high torque, low speed conditions. This may limit performance and increase the total system cost. Also, the disc armature style motor is as much as ten times the cost of a conventional fractional horsepower DC brush motor.

SUMMARY

[0008] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0009] In accordance with an aspect of the present disclosure, a low-profile DC brush motor has a frame supporting a stator. The motor has an armature having a disk shaped lamination stack with coil windings. The lamination stack is affixed to an armature shaft that extends through the lamination stack. The lamination stack has a diameter and a height with a diameter to height ratio in the range of (6.0 - 8.0) to 1 . The motor has a disk shaped commutator affixed to the armature shaft having radially outwardly facing brush contact surfaces that are contacted in a radial direction by brushes of the motor that are held in brush holders of the motor. The commutator has a diameter and a height with a diameter to height ratio in the range of (10.0 - 15.0) to 1. A ratio of the diameter of the commutator to the diameter of the lamination stack is in the range of (0.5 - 1 .0) to 1 .0.

[0010] In an aspect, the diameter of the lamination stack is in the range of 4.0 inches to 6.0 inches.

[0011] In an aspect, the motor has a rated power of one horsepower, the commutator has a diameter of 3.0 inches and a height of 0.25 inches, and the lamination stack has a diameter of 5.0 inches and a height of 0.75 inches.

[0012] In an aspect, the motor is a DC permanent magnet motor having a permanent magnet stator that includes a stator housing with one or more permanent magnet pole pairs affixed to the stator housing.

[0013] In an aspect, the motor is a universal motor having a wound stator that includes a stator yoke wound with stator coil windings.

[0014] In an aspect, a food waste disposer has a motor section that includes the low-profile DC brush motor. The food waste disposer has a food conveying section and a grind and discharge section disposed between the food conveying section and the motor section. The grind and discharge section has a grind section and a discharge section. The grind section includes a grind mechanism with a stationary grind ring and a rotating shredder plate assembly. The rotating shredder plate assembly including a rotatable shredder plate having lugs, the grind section including a grind housing that encompasses the grind mechanism and holds the stationary grind ring.

[0015] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. DRAWINGS

[0016] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0017] Fig. 1 is a cross-section perspective view of a low-profile fractional horsepower permanent magnet DC brush motor in accordance with an aspect of the present disclosure;

[0018] Fig. 2 is a perspective view of a commutator of the motor of

Fig. 1 ;

[0019] Fig. 3 is a perspective view of a lamination stack of the motor of Fig. 1 ;

[0020] Fig. 4 is a cross-section perspective view of a low-profile fractional horsepower universal motor in accordance with an aspect of the present disclosure; and

[0021] Fig. 5 is a cross-section perspective view of a food waste disposer having the low-profile motor of either Fig. 1 or Fig. 4 in accordance with an aspect of the present disclosure.

[0022] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0023] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0024] In accordance with an aspect of the present disclosure, a low-profile fractional horsepower DC brush motor 100 (Fig. 1 ) or a low profile fractional horsepower universal motor 100' (Fig. 4) has a frame 102 that supports a stator 104 and brush holders 106. It should be understood that as used herein, low-profile means that motor 100 and 100' have a reduced height compared to conventional fractional horsepower brush motors having the same rated power.

[0025] In the example of Fig. 1 , low-profile fractional horsepower

DC brush motor 100 is a permanent magnet DC motor. Stator 104 has a housing 105 that is illustratively a steel tube but can be other structures and other ferromagnetic material. One or more magnet pole sets 108 are affixed to stator housing 105. Each magnet pole set 108 includes a pair of permanent magnets 1 10 that are on opposite sides of stator housing 105 from each other. Stator housing 105 surrounds an armature 1 12. In the example of Fig. 1 , motor 100 is a two-pole motor with stator having one pole set 108 with one of magnets 1 10 of magnet pole set 108 oriented so that its North Pole faces armature 1 12 and the other one of magnets 1 10 of magnet pole set 108 oriented so that its South Pole faces armature 1 12. It should be understood that motor 100 can have integer multiples of two poles {e.g., 4, 6, 8, etc.) with stator 104 having a magnet pole set 108 for each two poles with magnets 1 10 of the magnet pole sets 108 affixed to stator housing 105 and oriented to provide consecutive alternating North and South poles.

[0026] Armature 1 12 includes a lamination stack 1 14, an armature shaft 1 16 that extends through lamination stack 1 14 and to which lamination stack 1 14 is affixed, and coil windings 1 18 wound in slots (not shown) of lamination stack 1 14 with end turns 120 of coil windings 1 18 extending around opposed ends of lamination stack 1 14. Armature shaft 1 16 is entrained for rotation in a bearing 1 17 of motor frame 102. It should be understood that a bushing could be used instead of a bearing. While the embodiment of Fig. 1 has bearing 1 17 on one side of motor 100, at the bottom as oriented in Fig. 1 , it should be understood that motor frame 102 can have a second bearing (or bushing) on the opposite side of lamination stack 1 14 (the top side as oriented in Fig. 1 ) in which armature shaft 1 16 is entrained for rotation.

[0027] A commutator 122 that is disk shaped is affixed to armature shaft 1 16 at one side of lamination stack 1 14 and coil windings 1 18. Commutator 122 has a disk shaped body 124 that includes a plurality of conductive segments 126 (best shown in Fig. 2) insulated from each other by an insulative support core 128. The conductive segments 126 are equally spaced around disk shaped body 124. In an aspect, insulative support core 128 is a molding of electrically non-conductive plastic with conductive segments 126 insert molded therein during molding of insulative support core 128 to form disk shaped body 124. Each conductive segment 126 has a truncated triangular shape with an arcuate radially inner end 130 and an arcuate radially outer end 132. A radially outward facing surface 134 of radially outer end 132 provides a brush contact surface 136. Ends 137 of individual ones of coil windings 1 18 are connected to respective individual ones of conductive segments 126 of commutator 122. The brush contact surface 136 of each conductive segment 126 is contacted by each brush 138 of motor 100 as that brush contact surface 136 passes by that brush 138 as commutator 122 rotates when motor 100 is running. In the example shown in Fig. 1 , since motor 100 is a two-pole motor, motor 100 has two brushes 138 on opposite sides of commutator 122. Brushes 138 are held in brush holders 106. An output of a rectifier 142 is connected to each brush 138. While rectifier 142 is shown as part of motor 100 in the embodiment of Fig. 1 , it should be understood that rectifier 142 could be separate from motor 100.

[0028] In an aspect, a cross-section of conductive segment 126 from inner to outer ends 130, 132 is generally U-shaped with inner and outer ends 130, 132 extending downwardly (as oriented in Fig. 1 ) from a top section 131 of the conductive segment 126 with the top section 131 being a bight of the U-shape. Insulative support core 128 fills the space between the inner and outer ends 130, 132 as well as space between inner end 130 and a metal hub 133 through which armature shaft 1 16 extends.

[0029] With reference to Fig. 2, commutator 122 has a diameter 144 and a height 146. With reference to Fig. 3, lamination stack 1 14 has a diameter 148 and a height 150. A ratio of the diameter 144 to height 146 of commutator 122 is in the range of (10.0 - 15.0) to 1 . A ratio of the diameter 148 to height 150 of lamination stack 1 14 is in the range of (6.0 - 8.0) to 1 . A ratio of the diameter 144 of commutator 122 to the diameter 148 of lamination stack 1 14 is in the range of (0.5 - 1 .0) to 1 .0. In an aspect, the diameter of the lamination stack is in the range of 4.0 inches to 6.0 inches.

[0030] In an example motor 100 has a rated power of one horsepower. In this example, commutator 122 has a diameter of 3.0 inches, a height of 0.25 inches and lamination stack 1 14 has a diameter of 5.0 inches and a height of 0.75 inches.

[0031] In the example of Fig. 4, low-profile fractional horsepower DC brush motor 100' is a universal motor. Motor 100' has a stator 404 that is a wound stator having a stator yoke 400 having one or more pairs of pole pieces 402 wound with stator coil windings 405. Stator 404 has a pair of pole pieces 402 with corresponding stator coil windings 405 for each two poles. As in the case of the permanent magnet DC motor 100 described above with reference to Fig. 1 , motor 100' can have two poles or integer multiples of two poles (4, 6, 8, etc.). Motor 100' is otherwise the same as motor 100 described above.

[0032] The low-profile fractional horsepower DC brush motor can advantageously be used in motorized devices where it is desirable to reduce the height of the device. One example is food waste disposers. Fig. 5 shows an example of a food waste disposer 500 having an above described low-profile fractional horsepower DC brush motor, such as motor 100 or motor 100'. For convenience, the following description of food waste disposer 500 refers to the motor as motor 100 but it should be understood that the motor could alternatively be motor 100'.

[0033] Food waste disposer 500 includes a grind and discharge section 513 disposed between a food conveying section 516 and a motor section 518. The grind and discharge section 513 includes a grind section 514 and a discharge section 515. The grind section 514 includes a grind mechanism 519 with a stationary grind ring 520 and a rotating shredder plate assembly 522. The shredder plate assembly includes a shredder plate 548 on which lugs 530 are rotatably fastened. Lugs 530 are illustratively swivel lugs, but it should be understood that they could be fixed lugs, or include both swivel lugs and fixed lugs.

[0034] The grind section 514 includes a grind housing 526 that encompasses the grind mechanism 519. The grind housing 526 may be fastened to an upper end bell (UEB) 528 of the discharge section 515 and holds the grind ring 520. The grind ring 520 is mounted in a fixed (stationary) position within the grind housing 526. The grind ring 520 includes teeth 529. The grind ring 520 may be fixedly affixed to an inner surface of the grind housing 526 by an interference fit and may be composed, for example, of galvanized steel.

[0035] The food conveying section 516 includes an inlet housing 531 with a first inlet 532. The first inlet 532 receives food waste and water. The inlet housing 531 may be a metal housing or an injection molded plastic housing. The inlet housing 531 also includes a second inlet 533 for receiving water discharged from a dishwasher (not shown). The inlet housing 531 may be integrally formed with the grind housing 526, such as by injection-molding both of the housings 526, 531 as a single component.

[0036] Except for motor section 518, food waste disposer 500 is typical of a prior art food waste disposer. Since motor 100 is shorter albeit wider than prior art brush DC motors, motor section 18 is illustratively shorter than the comparable motor section of the above referenced typical prior art food waste disposer.

[0037] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.