Patent Application
20060096328
This application claims the benefit from Korean Patent Application No. 2004-91469, filed on Nov. 10, 2004 in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a drum-type washing machine, and, more particularly, to a drum-type washing machine including a damper to reduce vibration transmitted to a water tub, and method.
2. Description of the Related Art
In general, a drum-type washing machine is an apparatus in which laundry contained in a cylindrical rotating tub is raised and subsequently falls down during rotation of the rotating tub, so as to be washed by virtue of an impact applied thereto when the laundry falls down.
A conventional drum-type washing machine, as disclosed in Japanese Patent Laid-Open No. 2000-237490, includes an external housing, a cylindrical water tub installed in the housing and configured to contain wash water supplied from an opened side, and a cylindrical rotating tub installed in the water tub. The rotating tub is configured to rotate by a driving force from a drive motor mounted in a lower region of the housing. The rotating tub has a plurality of through-holes perforated at a circumferential wall thereof for the in-flow or out-flow of wash water.
The water tub is provided, at an upper side thereof, with suspension springs that elastically support the water tub in a suspended state inside the housing. The water tub is provided, at a lower side thereof, with damper units that support the water tub in a shock absorbing manner to reduce vibration generated during the operation of the washing machine.
Each damper unit includes a circular hollow cylinder, a piston having one end reciprocably received inside the cylinder, and one or more frictional pads disposed around an outer surface of the piston to come into frictional contact with an inner surface of the cylinder and configured to emit a force applied to the piston due to vibration transmitted from the water tub, in the form of heat, thereby enabling reduction of the vibration.
In the conventional drum-type washing machine configured as stated above, however, even if a low degree of vibration is generated in the water tub, as the rotating tub rotates at a high speed, the vibration is entirely transmitted to the housing since the frictional force acts between the frictional pad and the inner surface of the cylinder.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.
The present invention addresses the above mentioned problem, and an aspect of the invention provides a drum-type washing machine which can effectively reduce various degrees of vibration transmitted to a water tub.
In accordance with one aspect of the present invention a drum-type washing machine includes an external housing, a water tub mounted in the housing in a suspended state, and a damper unit having one end affixed to an outer surface of the water tub and the other end affixed to the housing to thereby reduce vibration of the water tub. The damper unit includes a cylinder having one end affixed to one of the housing and the water tub and an other end having an opening. The damper unit also includes a piston having one end affixed to the other one of the housing and the water tub and the other end reciprocably received in the cylinder. The piston is retractable and reduces the vibration. The damper unit also includes a frictional pad positioned on an inner surface of the cylinder or an outer surface of the piston to come into frictional contact with, respectively, the outer surface of the piston or the inner surface of the cylinder, thereby reducing the vibration transmitted from the water tub to the piston.
According to an aspect of the present invention, the piston includes a first rod having one end affixed to one of the housing and the water tub and an other end inserted in the cylinder, and a second rod in the cylinder and connected to the first rod by an elastic member.
According to another aspect of the present invention, the second rod has a plurality of grooves recessed in an outer surface thereof for the insertion of the respective frictional pads.
According to another aspect of the present invention, a plurality of frictional pads are provided including a first frictional pad interposed between the inner surface of the cylinder and an outer surface of the first rod, and a second frictional pad interposed between the inner surface of the cylinder and an outer surface of the second rod.
According to another aspect of the present invention, the first rod has a first groove recessed in the outer surface thereof for the insertion of the first frictional pad, and the second rod has a second groove recessed in the outer surface thereof for the insertion of the second frictional pad.
According to another aspect of the present invention, the cylinder has a first groove recessed in the inner surface thereof for the insertion of the first frictional pad, and the second rod a second groove recessed in the outer surface thereof for the insertion of the second frictional pad.
In accordance with another aspect of the present invention, a drum-type washing machine includes an external housing, a water tub mounted in the housing in a suspended state, and a damper unit having one end affixed to an outer surface of the water tub and the other end affixed to the housing to thereby reduce vibration of the water tub. The damper unit includes a cylinder having one end affixed to one of the housing and the water tub and the other end having an opening. The damper also includes a first rod having one end affixed to the other one of the housing and the water tub and the other end reciprocably received in the cylinder and a second rod in the cylinder and connected to the first rod by an elastic member. The damper also includes a frictional pad interposed between an inner surface of the cylinder and an outer surface of at least one of the first and second rods and coming into frictional contact with the inner surface of the cylinder, thereby reducing the vibration transmitted from the water tub to the piston.
According to an aspect of the present invention, a method of reducing vibration in a washing machine is provided. In another aspect of the present invention, a damper reducing vibration is provided.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
These and/or other aspects and advantages of the invention will become apparent and more easily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
The water tub 11 and the rotating tub 12 each have an opening at their front sides to put laundry into, or take it laundry out of, the rotating tub 12. A door 13 is hinged at a front side of the housing 10 to open or close the openings of the water tub 11 and the rotating tub 12.
The water tub 11 is suspended in the housing 10 by means of at least one suspension spring 14 coupled to an upper side of the water tub 11 to elastically support the water tub 11. A drainage pipe 15 and a drainage pump 16 are mounted at a lower side of the water tub 11 to discharge wash water to the outside.
The rotating tub 12 is configured to rotate upon receiving a driving force from a drive motor 17 mounted in a lower region of the housing 10. The rotating tub 12 has a plurality of through-holes 12a at a circumferential wall thereof for the inflow or outflow of wash water. A plurality of lifters 12b protrude inwardly from an inner surface of the rotating tub 12 to raise laundry contained in the rotating tub 12 and to thereby wash the laundry by virtue of an impact applied to the laundry when the laundry falls down.
The drum-type washing machine further includes a damper unit 20 that supports the water tub 11 in a shock absorbing manner to reduce vibration generated in the water tub 11 as the rotating tub 12 rotates.
In the first example embodiment of the present invention, the piston 22 is variable in length in an elastic manner. When a low degree of vibration is transmitted from the water tub 11 to the piston 22, the vibration is sufficiently reduced as the piston 22 is elastically contracted. Therefore, an action of a frictional force between the frictional pad 23 and the inner surface of the cylinder 21 is not required. Thus, transmission of the vibration to the outside is reduced.
To achieve such an elastically retractable configuration, the piston 22 includes a first rod 22a having one end hingedly attached to the water tub 11 and an other end inserted in the cylinder 21. A second rod 22b is installed in the cylinder 21 so as to reciprocate upon receiving a force from the first rod 22a. An elastic member 22c is positioned between the first rod 22a and the second rod 22b so as to connect the first and second rods. The elastic member 22c is made of an elastically deformable material and configured to absorb part of the force transmitted from the first rod 22a and transmit the remaining force to the second rod 22b, thereby causing the second rod 22b to reciprocate inside the cylinder 21.
According to another example embodiment of the present invention, a pair of the frictional pads 23 are axially arranged in parallel around the second rod 22b. The second rod 22b has a pair of grooves 22d for the insertion of the frictional pads 23.
With the damper unit 20 of the first example embodiment, when a force that is less than an absorbing power of the elastic member 22c is applied to the piston 22 due to a vibration of the water tub 11, the elastic member 22c completely absorb the force as the elastic member 22c is elastically deformed, i.e. contracted and expanded, thereby reducing the vibration of the water tub 11. On the other hand, when a force greater than the absorbing power of the elastic member 22c is applied to the piston 22 due to the vibration of the water tub 11, only part of the force is absorbed as the elastic member 22c is elastically deformed, i.e., contracted and expanded. The remaining force is absorbed as the frictional pad 23 affixed around the second rod 22b moves within the cylinder 21 and is in frictional contact with the inner surface of the cylinder 21.
The damper unit of the second embodiment, designated as reference numeral 30, includes a hollow cylinder 31, e.g., circular in shape having one end affixed to the bottom surface of the housing 10, a piston 32 having one end affixed to a lower location of the outer surface of the water tub 11 and the other end reciprocably received in the cylinder 31. The damper unit also includes frictional pads 33 and 34 arranged around the piston 32 so as to come into frictional contact with an inner surface of the cylinder 31 as the piston 32 reciprocates in the cylinder 31 to convert a force applied to the piston 32 due to the vibration of the water tub 11 into heat, thereby enabling reduction of the vibration.
The piston 32 includes a first rod 32a having one end hingedly attached to the water tub 11 and the other end within the cylinder 31. A second rod 32b is positioned in the cylinder 31 so as to reciprocate upon receiving a force from the first rod 32a. An elastic member 32c is interposed between the first rod 32a and the second rod 32b so as to connect them to each other, the elastic member 32c made of an elastically deformable material and configured to absorb part of the force transmitted from the first rod 32a and transmit the remaining force to the second rod 32b, thereby reciprocating the second rod 32b inside the cylinder 31.
In the second example embodiment, the frictional pads 33 and 34 include a first frictional pad 33 positioned around the first rod 32a and a second frictional pad 34 positioned around the second rod 32b. The first and second rod 32a and 32b have first and second grooves 32d and 32e, respectively, for the insertion of the first and second frictional pads 33 and 34.
With the damper unit 30 of the second example embodiment, when a force less than a sum of a frictional force acting between the first and second frictional pads 33 and 34 and the inner surface of the cylinder 31 and an absorbing power of the elastic member 32c is applied to the piston 32 part of the force is absorbed as the first frictional pad 33 affixed on the first rod 32a moves along in the cylinder 31 coming in frictional contact with the inner surface of the cylinder 31. The remaining force is absorbed as the elastic member 22c is elastically deformed, i.e. contracted and expanded.
On the other hand, when a force greater than the sum of a frictional force acting between the first and second frictional pads 33 and 34 and the inner surface of the cylinder 31 and an absorbing power of the elastic member 32c is applied to the piston 32, part of the force is absorbed as the elastic member 32c is elastically deformed, i.e. contracted and expanded, and the remaining force is absorbed as the frictional pads 33 and 34 move within the cylinder 31 coming into frictional contact with the inner surface of the cylinder 31.
According to aspects of the present a damper unit, for use in a drum-type washing machine, in which a piston is elastically retractable to reduce vibration applied thereto is provided. With such a damper unit, if a relatively low degree of vibration is applied to the piston, the vibration can be reduced simply as the piston is elastically contracted and expanded without assistance of frictional pads configured to come into frictional contact with the inner surface of a cylinder or the outer surface of the piston. Such a configuration enables a more effective reduction of the vibration transmitted from a water tub to the piston.
Although the embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-91469 | Nov 2004 | KR | national |
