KR200422514Y1 - Motor starting switch - Google Patents

Abstract

The switch for an electric motor according to the present invention prevents vibration noise during motor operation. The switch includes a walled housing, electrical terminals, and a flexible switch arm. The control lever may abut the switch arm to drive the movement of the switch arm between the abutting and non-contacting positions of the electrical terminal. To prevent vibration of the lever during motor operation, the cantilever spring is pushed to move the lever toward the normal stop position against the wall of the housing. This spring is attached to the switch arm.

Electric, motor, switch, vibration, terminal, arm, lever, spring.

Description

Motor starting switch {MOTOR STARTING SWITCH}

The present invention generally relates to electric motors, in particular switches for starting electric motors which prevent vibrations and the resulting noises during motor operation.

Capacitor starting and phase induction motors, such as motors used in electrical appliances (eg, clothes dryers), typically have drive and start windings arranged in a stator assembly. This starting winding causes an electric current to flow at the start of the motor or when the motor speed drops below a certain operating speed, thereby forming a rotating magnetic field on the stator and applying sufficient torque to the rotor for starting purposes. However, as long as the motor is accelerated to the desired operating speed, or a predetermined percentage thereof, the rotor follows the alternation of the magnetic field formed by the drive winding, and the start winding is no longer needed. This starting winding is not intended for continuous use and may break if the current is not cut off during normal operation of the motor. Thus, a two-position start switch is provided in the motor to allow current to flow in the start winding only when the motor is started and to cut off the current in the start winding when the motor achieves the desired operating speed. For a more detailed description of this type of switch, see assigned US Pat. Nos. 4,296,366, 5,744,883 and 6,184,484, which are incorporated herein by reference.

Such motor start switches are typically operated by centrifugal actuators mounted on the rotor shaft of the motor and capable of rotating together. The centrifugal actuator responds to the speed of the motor to operate the start switch from its start position to its operating position in response to the motor reaching a predetermined operating speed. This centrifugal actuator engages the lever of the switch and moves to change one or more electrical contacts on the switch. This lever pushes one or more metal spring arms into or out of contact with a contact with a corresponding electrical terminal, thereby flowing current in one of the windings and breaking the current in the other. Typically, this lever pushes the spring arm in the switch's actuation position and releases the spring arm in the switch's actuation position. Unfortunately, these levers tend to vibrate and produce rattling noises during normal operation of the motor. In the operating position, this lever cannot tolerate significant loads due to design tolerances and freely move a small distance within the switch. This causes the lever to vibrate at the frequency associated with the motor and come into contact with components that cause unpleasant noise nearby. This vibration tendency is further exacerbated by levers made of lightweight materials such as plastics.

In response to this trend, some manufacturers have installed coil springs in each switch. This spring urges the lever to abut against other parts, such as the outer wall of the switch housing, so that the lever is normally held to stop when it is in its operating position and will not rattle. The restoring force of the spring can be overcome directly by the centrifugal actuator to move the lever to its starting position. Unfortunately, this coil spring increases costs, increases complexity in manufacturing, and reduces switch durability.

Among the various objects and features of the present invention, there is provided a switch for an electric motor that prevents vibration noise; Providing a durable switch in operation; The provision of economical switches to produce can be noted.

In general, the switch according to the present invention is for an electric motor. The switch includes a walled housing and electrical terminals in the housing. The flexible switch arm has a fixed end fixed in the housing and a first position in which the arm is in contact with the electrical terminal, thereby creating an electrical contact that affects the operation of the motor and the electrical contact away from the electrical terminal. It has a free end that can move between these second positions. A control member that is movable to move the switch arm between the first position and the second position may contact the switch arm. The biasing member is for pushing the control member to move toward the stop position, usually with respect to the wall of the housing, in order to prevent vibration of the control member during motor operation. This biasing member is attached to the switch arm.

In another embodiment, the present invention includes a switch for an improved electric motor having a wall defining a housing and an electrical terminal in the housing. The flexible switch arm is free to move between a fixed end and a first position in which the arm abuts an electrical terminal, thereby creating an electrical contact that affects the operation of the motor, and a second position in which the arm is away from the electrical terminal. Have a sweet The pivotally mounted lever may abut the switch arm to move the switch arm between this first and second positions. An improvement is to prevent the vibration of the lever during motor operation by including a cantilever spring attached to the switch arm and abutting the lever to push the lever toward the stop position, usually against the wall of the housing.

Other objects and features of the present invention will be described in detail below.

1 is a schematic side view of a switch according to the prior art.

Figure 2 is a view similar to Figure 1 of the switch according to the present invention.

3 is a plan view of the flexible switch arm and cantilever spring.

Corresponding reference numerals in the drawings indicate corresponding parts.

Referring now to the drawings and in particular to FIG. 2, the switch according to the first embodiment of the present invention is shown generally at 10. This switch 10 is intended for electric motors (not shown), such as capacitor start or phase induction motors, but may have other applications. In one embodiment, the switch 10 includes a start switch for selectively flowing or breaking current in the start winding and the drive winding of the motor. However, this switch can be used in a variety of applications for changing electrical circuits without departing from the scope of the present invention. As explained below, this switch is an improvement over the prior art switch 20 shown in FIG.

The switch 20 of FIG. 1 consists entirely of a housing, generally indicated at 22, several electrical terminals 24 and two flexible switch arms 26 that can be in contact with the selected terminal. By creating or releasing electrical contact between the switch arm 26 and the terminal 24, the corresponding electrical circuit is closed or opened, respectively, which affects the operation of the motor.

The housing 22 has a support formation 30 for supporting the peripheral wall 28 and the electrical terminals 24. The housing 22 has a shape and size suitable for mounting a switch in or next to the electric motor. A removable front cover (not shown) covers the interior of the housing 22. The housing is preferably molded from a suitably hard and electrically insulating material, such as plastic or synthetic resin.

These electrical terminals 24 generally comprise thin bands made of a hard, electrically conductive material (eg, a brass alloy). Each terminal 24 has a curved shape with an overall L-shape, suitable for mounting in the housing 22 and for electrical connection with the switch arm 26. This terminal 24 is mounted in a fixed position and received through slots formed in the support formation 30 of the housing. Each terminal 24 extends to a position adjacent the side of the housing 22 (bottom in FIG. 1) suitable for connecting with other components of an electrical circuit (not shown) in the motor. The electrical contacts, indicated at 32, depend on the terminals selected.

Each switch arm 26 has a fixed end 34 securely attached to one of the electrical terminals 24 by riveting, attachment welding, or other suitable connection. The free end 36 of each arm carries the electrical contact 38. This arm 26 is flexible and consists of a suitable resilient electrical conducting material such as copper beryllium. The free end 36 has a first position (one arm shown in dashed line in FIG. 1) in which the arm 26 abuts the electrical terminal 24 and makes electrical contact therebetween, and the arm is from the electrical terminal. It can move between falling second positions. This switch arm 26 has a single terminal 24 such that the electrical contacts 38 cooperate with the electrical contacts 32 forming a single pole single acting switch, as shown by the upper arm 26 in FIG. 1. You can only touch). Alternatively, the free end of this arm may be mounted between two terminals 24 forming a single pole double action switch, as shown by the lower arm 26 in FIG. Each arm 26 is formed such that it is usually biased with a spring toward the contact with each contact 32, which is usually the operating position of the switch that causes current to flow through the drive winding of the motor.

A lever (widely " control member "), generally designated 40, can be in contact with at least one switch arm 26 for actuation movement of the arm (s). This lever 40 is mounted on the housing 22 at a central hub 42 and has an inner leg 44 into the housing and an outer leg 46 out of the housing. The upper end of this outer leg 46 includes an engagement surface 48 defining a cam follower to engage a centrifugal actuator (not shown) mounted on the rotor shaft of the motor. The centrifugal actuator moves lever 40 in response to motor speed for position control. Conventionally, this lever 40 responds to the centrifugal actuator so that it is in one of two positions corresponding to the driving and starting states of the motor. This lever is formed of a suitably hard material such as plastic.

The inner leg 44 of the lever is formed to abut one or both of the switch arms 26. This inner leg comprises a first joint 50 and a second joint 52 comprising tabs integrated in the lever 40 and formed approximately perpendicular to the switch arms 26. This first junction 50 (upper junction in FIG. 1) is usually located at the end of the inner leg 44. This junction comprises a first end 54 which may abut the switch arm 26 and an opposite second end 56 which may abut the wall 28 of the housing. This second joint 52 extends from a portion of the lever 40 that includes a panel 58 passing behind the upper switch arm 26 and allows the lever to rotate without engaging the panel with the switch arm.

Since the lever 40 is the same as the conventional one, it will not be described in more detail here.

The switch 20 includes a coil spring 60 extending between the housing 22 and the lever 40. The purpose of this spring is to prevent rattling noise by dampening the vibration of the lever 40 during motor operation. The coil spring 60 rotates the lever 40 to a position such that the second end 56 of the first joint 50 abuts the wall of the housing. As a result, this lever is usually in a stationary state and vibration noise can be avoided. The force exerted on the lever 40 by the spring 60 is immediately overcome by the deliberate movement of the lever, such as when the centrifugal actuator moves the switch to the starting position.

The switch 10 shown in FIG. 2 is substantially the same as the switch of FIG. 1 except that the switch 10 does not have a coil spring 60 positioned opposite the housing (and the same parts are The same reference numerals). Instead, a dual-purpose switch arm (upper switch arm in FIG. 2) is provided, generally indicated at 70. The arm 70 includes a biasing member 72 which abuts against the first end 54 of the junction, which pushes the junction 50 towards the wall of the housing. This biasing member 72 includes a cantilever spring extending from the switch arm 70 and abutting against the inner leg 44 of the lever 40 for pushing against the wall of the housing toward the normal stop position, thereby allowing the lever to act upon the motor. Prevent vibration The cantilever spring 72 usually has a fixed proximal end and a distal free end connected to the switch arm 70 at a portion adjacent the fixed end 34 of the switch arm. Has a free distal end. The free end 36 of the switch arm 70 is prevented from moving over by contacting with the corresponding electrical terminal 24, while the spring 72 is shorter than the switch arm so that the spring is connected to the junction ( It is not restricted in moving upward until it comes in contact with 50). The abutment of the cantilever spring 72 with the abutment is greater than that of the coil spring 60 according to the prior art of FIG. 1 with a greater moment arm for rotation around the hub 42 of the lever 40. To provide. Therefore, the force exerted by this spring 72 is more effective in terms of vibration dampening. It will be appreciated that, like other spring configurations including coil springs, biased members of other shapes do not depart from the scope of the present invention. For example, this spring 72 may be longer than the switch arm 70. In this configuration (not shown), the spring has a lateral position that avoids contact with the terminal 24 for vertical movement through the terminal while extending horizontally adjacent. In another embodiment (not shown), the dual-purpose switch arm 70 may be a lower switch arm and the upper switch arm 26 may be conventional.

Referring to FIG. 3, the cantilever spring 72 includes an integral portion of the switch arm 70. In this embodiment, the spring 72 is formed by cutting the switch arm 70 along cutting lines 74 defining the edges of the spring. Advantageously, the proximal stationary end of the spring 72 is usually connected to the switch arm in a position adjacent the stationary end 34 of the switch arm 70 to provide a spring with a long beam length so that the distal free end is switched Deflected with sufficient distance from the arm abuts against and exerts a force on the junction 50. This spring 72 is dimensioned so that the remaining portion of the switch arm 70 has a sufficient area to allow sufficient current to flow through the switch 10. The force exerted on the lever 40 by the spring 72 is immediately overcome by the deliberate movement of the lever, such as when the centrifugal actuator moves the switch to the starting position. As shown in FIG. 3, the spring 72 is a long rectangular strip that usually extends along the longitudinal centerline of the switch arm 70. However, this spring may have other shapes and positions. For example, the spring may be disposed along one or both sides of the switch arm side. The spring may also be a separate piece attached to the switch arm in a suitable manner.

In short, the switch arm 70 of the present invention accomplishes two purposes. First, make selected electrical contacts that control the operation of the motor. Second, it cushions the rattling of the lever. Eliminating coil spring components reduces production costs and reduces the time required to install and improves durability in operation by avoiding potential sources of failure, such as when coil spring 60 is pulled out or broken.

It will be appreciated that a switch with other numbers of terminals and switch arms, including a single terminal or switch arm, does not depart from the scope of the present invention. The lever may abut one switch arm and / or have only one joint. Moreover, this lever has no joint and another part, for example the body of the inner leg, may contact the switch arm. It will also be appreciated that this switch may have a control member for moving the arm (s) with a non-lever form (eg, a translation rod).

In view of the above, it will be appreciated that various objects of the present invention are achieved and other advantageous effects are exerted.

When introducing the components of the present invention or its preferred embodiment (s), directives such as "one", "above", etc. are intended to mean that there are one or more components. Also, the terms "comprising", "having" and the like are intended to mean that there may be other components in addition to the generic and listed components.

As various modifications can be made without departing from the scope of the present invention, everything in the above description and shown in the following drawings is to be interpreted as illustrative and not in a limiting sense.

Claims (17)

A housing comprising a wall; An electrical terminal in the housing; Between a fixed end fixed in the housing, a first position in which the arm abuts the electrical terminal, thereby creating an electrical contact affecting the operation of the motor, and a second position in which the arm is away from the electrical terminal and no electrical contact. Flexible switch arm with movable free ends; An movable control member capable of controlling the switch arm to drive the movement of the switch arm between the first position and the second position; And A biasing member for pushing the control member toward the stop position with respect to the wall of the housing to prevent vibration of the control member when the motor is operated; The biasing member is attached to the switch arm. The method of claim 1, And the biasing member is integrally formed with the switch arm. The method of claim 1, The biasing member is a switch for an electric motor, characterized in that it comprises a cantilever spring. The method of claim 3, The cantilever spring has a proximal fixed end and a distal free end that are adjacent to the fixed end of the switch arm and are connected to the switch arm. An electric motor switch. The method of claim 3, And the cantilever spring includes a portion integral with the switch arm extending in the longitudinal direction of the switch arm. The method of claim 5, Wherein the entire portion of the switch arm comprises an elongated rectangular strip. The method of claim 1, And the control unit includes a lever rotatably mounted to the housing. The method of claim 7, wherein And the lever includes an inner leg inside the housing and an outer leg outside the housing, wherein the biasing member abuts on the inner leg. The method of claim 8, The inner leg of the lever includes a junction located at the end of the inner leg to abut against the switch arm. The method of claim 9, The junction includes a first end that may be in contact with the switch arm and an opposite second end that is in contact with the wall of the housing. The method of claim 10, The biasing member abuts against the first end of the junction to push the inner leg of the lever towards the wall of the housing. The method of claim 8, The biasing member is an electric motor switch, characterized in that formed integrally with the switch arm. The method of claim 12, The biasing member is a switch for an electric motor, characterized in that it comprises a cantilever spring. The method of claim 13, The cantilever spring has a proximal fixed end and a distal free end connected to the switch arm adjacent to the fixed end of the switch arm. The method of claim 13, And the cantilever spring includes a portion integral with the switch arm extending in the longitudinal direction of the switch arm. The method of claim 15, Wherein the entire portion of the switch arm comprises an elongated rectangular strip. A wall defining the housing and an electrical terminal in the housing, Flexible switch with fixed end and free end movable between the first position where the arm is in contact with the electrical terminal and thereby induces electrical contact affecting the operation of the motor and the second position where the arm is away from the electrical terminal Cancer, and A switch for an electric motor having a rotatably mounted lever capable of contacting a switch arm for moving the switch arm between the first and second positions, the switch comprising: And a cantilever spring attached to the switch arm and contacting the lever to push the lever toward the stop position against the wall of the housing to prevent vibration of the lever during motor operation. switch.

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