Description ROTATION TYPE OIL DAMPER

Technical Field

[1] The present invention relates to a rotation type oil damper. More specifically, the present invention relates to a rotation type oil damper which has a simple structure and a secure dampening ability with free adjustment of damping force in accordance with its rotation position. Background Art

[2] Rotation type dampers are typically adapted to doors, covers and cases that are rotatably opened and closed and the rotation type dampers prevent the doors, covers and cases from being closed too fast. Conventional rotation type dampers may be categorized into elastic member types that use an elastic member such as a spring and viscous fluid types that use viscous fluid to create a damping force. Of the two, the elastic member type generates a damping force in a clockwise and counter-clockwise direction. As a result, the elastic member type cannot be adapted if a damping force is required in only one direction and the damping force of the elastic member type cannot be maintained, because the elasticity of the elastic member is weakened as the elastic member is used a lot.

[3] On the other hand, the rotation type oil damper adapting a viscous fluid has viscous fluid inside a housing and a valve inside the housing rotates in closely contact with an inner circumferential surface of the housing. With this structure, a fluid path is formed in the valve and the viscous fluid pass through the fluid path. When the valve rotates, a damping force is generated by resistance caused by the flow of the viscous fluid. Such the conventional rotation type oil damper is disclosed in Korean Patent No. 414520 and Korean Utility Model No. 422594. Disclosure of Invention Technical Problem

[4] However, the above conventional rotation type oil damper has following disadvantages.

[5] First, there are many parts in the housing of the conventional rotation type oil damper. As a result, the structure of the damper might be complex and its fabrication process might be complicated, which causes a low productivity. Because of this complex structure, the fabrication cost might rise. In addition, since the overall size of the oil damper is large, the conventional rotation type oil damper has a limitation of being adapted to various fields.

[6] Furthermore, the viscous fluid of the housing in the conventional rotation type oil

damper might be flow outside, because the inside of the housing is not completely closed airtight. In addition, a structure in which the conventional rotation type oil damper is installed might be contaminated as well as the contamination of the oil damper itself because of the leakage of the viscous fluid. As the damper is used, the damping force of the conventional rotation type oil damper might deteriorate.

[7] A still further, it is necessary to adjust the damping force in accordance with a degree of the rotation, depending on the structure to which the conventional rotation type oil damper is applied. However, it is impossible to change a damping force of the conventional rotation type oil damper because a flow resistance of the viscous fluid which the valve inside the housing receives is constantly regular.

[8] A still further, the fluid path through which the viscous fluid of the conventional rotation type oil damper passes is provided asymmetrical with respect to a center shaft of the housing. As a result, the damping force is concentrated on a particular portion and the structure of the conventional rotation type oil damper is instable. That is, the damping force is generated at a portion where the fluid path is provided and thus the rotational motion of the valve that rotates about a center shaft of the housing might be instable.

Technical Solution

[9] To solve the problems, an object of the present invention is to provide a rotation type oil damper.

[10] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a rotation type oil damper includes a housing having an inner space therein; a rotational shaft inserted in the housing to form an airtight space in which viscous fluid is filled, the rotational shaft configured to damp a rotational force of an outer device as a blade formed in a predetermined portion of the rotational shaft moves in the viscous fluid, when rotating in communication with the outer device; a through hole that passes through the rotational shaft to communicate the airtight space with an outside; and a fixing member fixedly inserted in the through hole to close the through hole airtight.

[11] In the rotation type oil damper in accordance with an exemplary embodiment, the rotational shaft may include a partition part that forms the airtight space in a close contact with an inner surface of the inner space formed in the housing; a damping part comprising at least one blade submerged in the viscous fluid inside the airtight space and a passage hole provided in the at least one blade; and a driving part connected with the outer device, the driving part rotating together with the blade.

[12] In the rotation type oil damper, a cross-sectional radius of the airtight space may be variable in accordance with a rotational direction of the blade.

[13] In the rotation type oil damper, a gap between an inner surface of the airtight space and an end of the blade may gradually decrease as the blade rotates in one direction.

[14] In the rotation type oil damper, the passage hole may be formed at a lower end of the blade that contacts with a bottom of the housing.

[15] The rotation type oil damper in accordance with the embodiment may further include a first communication hole formed at a lower end of the damping part that contacts with a bottom of the housing, to make the through hole in communication with the airtight space.

[16] The rotation type oil damper may further include a second communication hole formed at an upper end of the damping part to make the through hole in communication with the airtight space.

[17] In the rotation type oil damper, the blade may be provided in pair inside the airtight space, facing each other in an opposite direction.

[18] The rotation type oil damper may further include a stopper projected toward an inside of the airtight space from an inner surface of the housing to limit a rotation angle of the rotational shaft.

[19] In the rotation type oil damper, the stopper may be provided in contact with an outer surface of the rotational shaft to partition the airtight space together with the rotational shaft.

[20] In another aspect of the present invention, a rotation type oil damper includes a housing having an inner space therein; a cover coupled to an upper portion of the housing; and a rotational shaft rotatable in the inner space of the housing, wherein the rotational shaft comprising, a partition part in close contact with the inner space to partition the inner space into an upper space and a lower space such that an airtight space is formed in the lower space; a damping part provided in a lower portion of the partition part, the damping part having at least one blade to partition the airtight space, wherein a passage hole is formed the at least blade to make the partitioned spaces in communication with each other; and a driving part provided in an upper portion of the partition part, the driving part secured to the damping part to rotate together with the damping part.

Advantageous Effects

[21] The present invention has following advantageous effects.

[22] First, a structure of an oil damper may be simple, because a rotational shaft rotatable inside a housing has an optimal structure. In addition, productivity of the oil damper may be enhanced, because the number of parts is smaller. [23] Furthermore, contamination of the device that might be caused by leaked oil can be prevented, because viscous fluid is efficiently prevented from being leaked outside. As

a result, even though it is used for a long time, the rotation type oil damper in accordance with the present invention may not have deterioration of damping efficiency but maintain a stable damping efficiency.

[24] A still further, the damping force of the oil damper may be adjusted freely in accordance with a rotational direction of a blade, because an appearance of an inner space of the housing is variable in accordance with a rotational direction of the blade. Especially, the inner space of the housing gradually increases in accordance with the rotation of the blade. The damping force can be adjusted freely in accordance with an object that the oil damper is applied to. For example, the damping force is not activated at first and the damping force is gradually activated as the blade rotates.

[25] A still further, the viscous fluid is prevented from being concentrated on a particular portion of the inner space formed in the housing that the viscous fluid is filled in, because the blade and a passage hole is provided symmetrically inside the housing, respectively. As a result, the structure of the oil damper may be designed stably. Brief Description of the Drawings

[26] The accompanying drawings, which are included to provide further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure.

[27] In the drawings:

[28] FIG. 1 is a perspective view illustrating a rotation type oil damper in accordance with an exemplary embodiment of the present invention;

[29] FIG. 2 is an exploded perspective view illustrating of the rotation oil damper shown in FIG. 1;

[30] FIG. 3 is a perspective view illustrating a rotational shaft of the rotation type oil damper shown in FIG. 1 ;

[31] FIG. 4 is a perspective view illustrating that the rotation type oil damper shown in

FIG. 1 is cut horizontally;

[32] FIG. 5 is a perspective view illustrating that the rotation type oil damper shown in

FIG. 1 is cut along an I-I line; and

[33] FIGS. 6 and 7 are sectional views illustrating rotation of the rotational shaft.

Best Mode for Carrying Out the Invention

[34] Reference will now be made in detail to the specific embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[35] FIG. 1 is a perspective view illustrating a rotation type oil damper in accordance with

an exemplary embodiment of the present invention. FIG. 2 is an exploded perspective view illustrating of the rotation oil damper shown in FIG. 1. FIG. 3 is a perspective view illustrating a rotational shaft of the rotation type oil damper shown in FIG. 1. FIG. 4 is a perspective view illustrating that the rotation type oil damper shown in FIG. 1 is cut horizontally. FIG. 5 is a perspective view illustrating that the rotation type oil damper shown in FIG. 1 is cut along an I-I line. FIGS. 6 and 7 are sectional views illustrating rotation of the rotational shaft.

[36] A rotation type oil damper 100 in accordance with an exemplary embodiment of the present invention includes a housing 110, a cover 120, a rotational shaft 130, as shown in FIGS. 1, 2 and 5. The cover 120 is coupled to an upper portion of the housing 110 and the rotational shaft 130 is provided in the housing 110.

[37] A predetermined inner space is formed in the housing 110 and the rotational shaft

130 is inserted in the inner space of the housing 110. In this embodiment, the inner space is formed in an approximately cylindrical shape.

[38] The housing 110 may be secured to an object, for example, a door, a cover and a case in various ways. The housing 110 may be insertedly secured to the object. Alternatively, a flange (not shown) or a securing hole (not shown) is formed at an outer surface of the housing 110 and the housing 110 is fixedly secured to the object by a securing member (not shown).

[39] The cover 120 is coupled to the upper portion of the housing 110. Specifically, as shown in FIG. 2, a securing hole 124 is formed at a corner of the cover 120 and a coupling hole 114 corresponding to the securing hole 124 is formed at the housing 110. A securing member 126 is inserted in the securing hole 124 and the coupling hole 114 to couple the cover 120 to the housing 110.

[40] A connection hole 122 is formed in a center of the cover 120 to structurally connect the rotational shaft 130 inserted in the housing 110 with an outer device. The rotational shaft 130 is rotatable in the inner space of the housing 110 and it is structurally connected with the outer device through the connection hole 122 formed at the cover 120.

[41] The rotational shaft 130 is inserted in the housing 110 and it forms an airtight space

(A) that is filled with viscous fluid, for example, oil. When the rotational shaft 130 rotates in communication with the outer device, a blade 152 formed at a predetermined portion of the rotational shaft 130 moves in the viscous fluid filed in the airtight space (A) to damp a rotational force of the outer device. For example, as shown in FIG. 2, such the rotational shaft 130 includes a partition part 140, a damping part 150 and a driving part 160.

[42] The partition part 140 formed in a shape corresponding to the inner space of the housing 110 contacts closely with an inner surface of the inner space to partition the

inner space into an upper portion and a lower portion. Thus, the airtight space (A) is formed in the lower portion of the partition part 140, being surrounded by the partition part 140 and the housing 110. Here, the viscous fluid, for example, oil is filled in the airtight space (A).

[43] To close airtight sides between the partition part 140 and the inner space of the housing 110 more efficiently, a sealing member 172 of a ring shape is inserted along an outer surface of the partition part 140. A recess 142 is formed at the partition part 140 to make the sealing member 172 installed smoothly.

[44] The damping part 150 is provided in the lower portion of the partition part 140 and it has plural blades 152. The blades 152 are submerged in the oil filled in the airtight space (A). As shown in FIG. 5, the blade 152 contacts with an inner surface of the airtight space (A) to partition the airtight space (A) into several unit spaces.

[45] In this embodiment, as shown in FIG. 3, the blade 152 is provided in pair and the pair is arranged in an opposite direction, facing each other. It is possible to prevent the damping force from being concentrated on a particular portion, because the blades 152 are symmetrical each other. As a result, a stable structure of the oil damper can be gained.

[46] A passage hole 154 may be formed in at least one blade 152, passing through the blade 152, to communicate the partitioned airtight spaces (A) with each other. In this embodiment, as shown in FIG. 3, the passage hole 154 is formed at each of the blades 152. The passage hole 154 is formed at a lower end of each blade 152 in an arc shape and the viscous fluid passes through the passage hole 154 in a state of the damping part 150 being in contact with the housing 110. Here, the lower end of each blade 152 contacts with a bottom of the housing 110. The viscous fluid filled in the airtight space (A) flows in the passage hole 154 and the damping force is generated by resistance against the flow of the viscous fluid through the passage hole 154.

[47] A through hole 136 is formed inside the rotational shaft 130. A first communication hole 156 and a second communication hole 158 are formed at a body of the damping part 150 to communicate the through hole 136 with the airtight space (A). In reference to FIGS. 3 and 4, the first communication hole 156 is formed at a lower end of the body of the damping part 150 and the second communication hole 158 is formed above the first communication hole 156. Because of the first and second communication hole 156 and 158, the viscous fluid is injected through the through hole 136 and the viscous fluid flows via the first communication hole 156 to be injected into the airtight space (A). Thus, air inside the airtight space (A) can be discharged through the second communication hole 158.

[48] The through hole 136 includes a first through portion 137 and a second through portion 138. The first and second through portion 137 and 138 have different

diameters, respectively. In this embodiment, the first through portion 137 positioned under the second through portion 138 has a smaller diameter than the second through portion 138. A fixing member 132 is fixedly inserted in the first through portion 137. Such the fixing member 132 shuts off between the first through portion 137 and the second through portion 138 to close airtight the viscous fluid filled in the airtight space (A) along the through hole 136. Here, a contact ring 134 is provided between the fixing member 132 and the first through portion 137 to improve the airtight close.

[49] The driving part 160 is formed as one body with the partition part 140 and the damping part 150. The driving part 160 rotates together with the damping part 150 and a securing groove 162 is formed in the driving part 160. Here, a hinge shaft (not shown) of the outer device is structurally connected with the securing groove 162. Specifically, a securing protrusion (not shown) projected from the hinge shaft is inserted in the securing groove 162. As a result, when the hinge shaft rotates, the whole rotational shaft 130 including the driving part 160 rotates together. A relative motion is generated at an end of the driving part 160 in relation with the cover 120 and thus a washer 174 may be provided between the cover 120 and the driving part 160.

[50] This embodiment presents that the partition part 140, the damping part 150 and the driving part 160 are formed as one body. However, it is possible to fabricate the three elements separately and assemble them each other. In the latter case, the partition part 140, the damping part 150 and the driving part 160 are configured of the rotational shaft 130 by assembling. Here, it is preferable to design a material and an assembly structure of the rotational shaft 130, considering strength for both the airtight close of viscous fluid and the transmission of torque.

[51] The rotation type oil damper 100 having the above structure will be assembled as follows. First, the sealing member 172 is secured to the partition part 140 of the rotational shaft 130 and the rotational shaft 130 having the sealing member 172 secured thereto is inserted in the inner space of the housing 110. At this time, the rotational shaft 130 is inserted to a bottom of the inner space so that an end of the rotational shaft 130, specifically, an end of the damping part 150 can contact with the bottom of the inner space. Hence, the cover 120 is secured to the housing 110, with the washer 174 being inserted between the housing 110 and the cover 120. After that, the cover 120 is secured to the housing 110 by four securing members 126.

[52] The viscous fluid, for example, oil is injected in the above structure configured of the housing 110, the rotational shaft 130 and the cover 120. At this time, the viscous fluid is injected via the connection hole 122 of the cover 120 and the through hole 136 of the rotational shaft 130. The injected viscous fluid passes through the second through portion 138 and the first through portion 137 in order. Then, through the first communication hole 156, the viscous fluid is injected in the airtight space (A) surrounded by

the partition part 140 and the housing 110. As the viscous fluid is injected, the air inside the airtight space (A) is discharged outside through the second communication hole 158 smoothly. After the viscous fluid is injected in the airtight space (A), the contact ring 134 and the fixing member 132 are coupled to the first through portion 137 of the through hole 136 in order. Then, the assembly of the rotation type oil damper 100 is complete.

[53] In the meantime, as shown in FIG. 5, a stopper 116 is provided at an inner surface of the housing 110. The stopper 116 is projected in a center direction of the housing 110 and it is projected toward an inside of the airtight space (A) to limit a rotational angle of the rotational shaft 130. Also, the stopper 116 is in contact with an outer surface of the damping part 150 of the rotational shaft 130 to partition the inner space of the housing, specifically, the airtight space (A). In this embodiment, as shown in FIG. 5, the pair of the blades 152 may be facing each other and the stopper 116 is also provided in pair, facing each other.

[54] In the rotation type oil damper 100 in accordance with the embodiment of the present invention, a cross-sectional radius of the airtight space (A) is variable in accordance with a rotational direction of the blade 152. That is, the section of the airtight space (A) is not exactly circular and the curvature of the airtight space (A) is variable in accordance with a rotational direction of the blade 152, as shown in FIGS. 6 and 7. In reference to FIGS. 6 and 7, in the housing 110 in accordance with this embodiment, the cross-sectional radius of the airtight space (A) decreases gradually in accordance with the rotational direction of the blade 152 and a gap between a side of the inner space and the blade 152 decreases gradually. That is, a rotational track (B) of the blade 152 and an inner section (C) of the inner space are different. The inner section (C) of the inner space decreases gradually in accordance with the rotational direction of the blade 152, so that it may contact with the rotational track (B) of the blade 152.

[55] In FIG. 6, the inner space of the housing 110, specifically, the airtight space (A) is larger than a width of the blade 152. As a result, the viscous fluid flows through an air gap between the end of the blade 152 and the inner surface of the airtight space (A) and there is a small damping force. However, as the blade 152 rotates along an arrow line direction shown in FIG. 6, the gap between the airtight space (A) of the housing and the blade 152 is gradually getting narrower only to make the damping force bigger. As shown in FIG. 7, if the pressure is gradually applied too much as the rotational angle of the blade 152 is increasing, the viscous fluid is slowly flowing into an opposite partitioned space through the passage hole 154 in a state of the end of the damping part 150 being in a close contact with the bottom of the housing 110 and the damping force is reduced, and vice versa if the blade 152 rotates in a state shown in FIG. 6.

[56] The oil damper 100 presented in the embodiment described above is applicable to a door that is able to be opened or closed as rotating about a horizontal shaft when a user pushes or pulls the door, for example, a home bar door of a refrigerator, a door of dishwasher or a door of an electric oven, which will be described briefly.

[57] For example, the blade 152 of the oil damper 100 may be provided in a position shown in FIG. 6 when a door having the oil damper 100 installed therein is closed. Hence, in a primary process of the door opening, the damping force generated by the oil damper 100 is relatively small enough for a user to open the door easily. If a rotational angle of the door is larger, the damping force of the oil damper 100 is getting bigger as described above in reference to FIGS. 6 and 7 and thus a rotational speed of the door gradually decreases. If the door rotates at more than a predetermined angle, the blade 152 is stopped by the stopper 116 as shown in FIG. 7 and the opening process of the door is complete smoothly without any shock. The door is closed in a process of vice versa.

[58] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Industrial Applicability

[59] The present invention has an industrial applicability.

[60] First, a structure of an oil damper may be simple, because a rotational shaft rotating in a housing has an optimal structure. In addition, productivity of the oil damper may be enhanced, because the number of parts is smaller.

[61] Furthermore, contamination of the device that might be caused by leaked oil can be prevented, because viscous fluid is efficiently prevented from being leaked outside. As a result, even though it is used for a long time, the rotation type oil damper in accordance with the present invention may not have deterioration of damping efficiency but maintain a stable damping efficiency.

[62] A still further, the damping force of the oil damper may be adjusted freely in accordance with a rotational direction of a blade, because an appearance of an inner space of the housing is variable in accordance with a rotational direction of the blade. Especially, the inner space of the housing gradually increases in accordance with the rotation of the blade. The damping force can be adjusted freely in accordance with an object that the oil damper is applied to. For example, the damping force is not activated at first and the damping force is gradually activated as the blade rotates.

[63] A still further, the viscous fluid is prevented from being concentrated on a particular

portion of the inner space formed in the housing that the viscous fluid is filled in, because the blade and a passage hole is provided symmetrically inside the housing, respectively. As a result, the structure of the oil damper may be designed stably.