JP2012183120A - Drum washing machine and door packing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drum washing machine in which low vibration may be realized.SOLUTION: A drum washing machine 1 comprises: a main body 10 having, in a front portion, an entry opening through which laundry is taken in and taken out; a water tub 20 swingably provided inside the main body 10 and having an opening 21 in a front portion; a rotary drum provided inside the water tub 20 to be rotated around a rotation axis 40 inclined at a prescribed angle and having an opening in a front portion; a driving motor 60 for driving the rotation axis 40; and a door packing 70 one end of which is fixed in a peripheral portion of the entry opening and the other end of which is fixed in a peripheral portion of the opening 21 of the water tub 20. The door packing 70 has a zigzag portion 75 formed along a circumferential direction.

Description

  The present invention relates to a drum-type washing machine that performs operations such as washing, rinsing, and dewatering using a rotating drum (washing tub) arranged with a rotating shaft close to horizontal, and a door packing used in the drum-type washing machine.

  2. Description of the Related Art Conventionally, a front loading type drum-type washing machine having a rotating drum whose rotating shaft is arranged substantially horizontally is known. (For example, refer to Patent Document 1).

  A drum-type washing machine generally includes a main body (outer box) that constitutes an external appearance, a bottomed cylindrical water tank included in the main body, and a rotating drum that is rotatably included in the water tank. The rotating drum rotates around a rotating shaft disposed substantially horizontally in the water tank. The main body and the water tank are each formed with an opening at the front, and each opening is connected by a door packing for maintaining watertightness.

  The door packing is formed in a substantially cylindrical shape. One end of the door packing is fixed to the periphery of the opening of the main body, and the other end is fixed to the periphery of the opening of the water tank. This door packing is only connected to the water tank and the main body as a countermeasure against water leakage, and should not be resistant to the shaking of the water tank. For this reason, the door packing is required to have a shape that can easily follow the swinging of the water tank.

  Therefore, in a conventional drum type washing machine, a bellows portion having a diameter that is substantially perpendicular to the axial direction of the rotation shaft is formed in the body portion of the door packing. The door packing easily follows the swinging of the water tank as the bellows part expands and contracts.

Japanese Patent No. 3530076

  Here, in the drum type washing machine, the water tank may swing in a direction substantially perpendicular to the axial direction of the rotating shaft. In this case, the door packing is displaced in a direction substantially perpendicular to the axial direction of the rotating shaft. At that time, shear deformation occurs in a part of the circumferential direction of the door packing.

  FIG. 15 is a schematic diagram for explaining the deformation of the door packing when the water tank is swung. With reference to FIG. 15, the deformation | transformation of the door packing at the time of a water tank rocking | swiveling is demonstrated. One end 370a of the door packing 370 is fixed to the periphery of the main body opening, and the other end 370b is fixed to the periphery of the water tank opening. When the water tank swings in a direction perpendicular to the axial direction (T direction) of the rotating shaft, the main body opening side of the door packing 370 is in a fixed state. ). That is, the door packing 370 is displaced in a direction substantially perpendicular to the axial direction (T direction) of the rotating shaft. At this time, a shear deformation region 380 that causes shear deformation in the circumferential direction is formed at a position shifted by ± 90 ° with respect to the displacement direction.

  As described above, in the drum type washing machine, when the water tank swings in a direction substantially perpendicular to the axial direction of the rotation shaft, shear deformation occurs in the door packing. However, the conventional drum-type washing machine has a disadvantage that the shear deformation region of the door packing is not easily deformed when the water tank swings as described above. Therefore, the conventional drum-type washing machine has a problem that the oscillation of the water tub is easily transmitted to the washing machine body, and the vibration of the body becomes large.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a drum type washing machine and a door packing capable of realizing low vibration. is there.

  In order to achieve the above object, a drum-type washing machine of the present invention includes a main body having a front / rear opening for loading and unloading laundry, and a water tub that is swingably mounted in the main body and has an opening on the front surface. A rotating drum that is built in the water tank and rotates around a rotating shaft inclined at a predetermined angle and has an opening on the front surface, driving means for driving the rotating shaft, and one end fixed to the peripheral edge of the inlet / outlet The other end is provided with an annular door packing fixed to the peripheral edge of the opening of the water tank. The door packing has a zigzag portion having a zigzag cross section extending in the circumferential direction and perpendicular to the axial direction on the circumferential surface.

  In the drum-type washing machine having the above-described configuration, a zigzag zigzag portion having a zigzag cross-sectional shape extending in the circumferential direction on the peripheral surface of the door packing and perpendicular to the axial direction is easily expanded and contracted in the circumferential direction. Therefore, even when the water tank swings in a substantially vertical direction with respect to the axial direction of the rotating shaft and the door packing undergoes shear deformation, the door packing easily follows the deformation. Thereby, since the influence of the shaking of the water tank is not easily transmitted to the main body of the washing machine, the main body vibration of the washing machine can be reduced.

  Moreover, it is preferable that the zigzag part of the door packing is formed in a bowl shape, and the ridgeline thereof is configured to be along the axial direction of the rotation shaft. If comprised in this way, since a door packing expands-contracts in the circumferential direction easily, it can make it difficult to transmit the influence of the rocking | fluctuation of a water tank to a washing machine main body easily.

  Note that the zigzag portion of the door packing may be formed in a wave shape other than the hook shape.

  Moreover, the zigzag part of the door packing may be formed in a part of the circumferential direction of the door packing. For example, the stress distribution of the door packing when the water tank is swung may be verified, and the zigzag portion may be formed in a region that becomes the maximum stress distribution region in the circumferential direction. If comprised in this way, since a zigzag part is provided in the maximum stress distribution area to which the load is the most, the dispersion | distribution of stress can be aimed at easily. In addition, the structure of the door packing can be simplified.

  Here, in the case of a drum-type washing machine, the water tank easily swings in the vertical direction (substantially vertical direction) of the main body due to the influence of gravity. Therefore, it is preferable that the zigzag portion of the door packing is provided so as to be symmetrical to each other at two positions shifted in the circumferential direction of ± 90 ° with respect to the substantially vertical direction of the main body.

  Moreover, it is preferable that the door packing has a single bellows portion which is bent in the direction of the rotation axis to form a mountain shape. In this case, the bellows part is preferably arranged on the outer peripheral side of the zigzag part, and the inner peripheral edge thereof is preferably connected to the zigzag part.

  The door packing of the present invention has a substantially cylindrical shape, and a zigzag portion having a zigzag cross section perpendicular to the cylindrical axis is provided on the peripheral surface. By using such a door packing in a drum type washing machine, main body vibration of the washing machine is reduced.

  Here, when the door packing is displaced in a direction substantially perpendicular to the axial direction of the rotating shaft, shear deformation occurs at a position shifted by ± 90 ° with respect to the displacement direction. For this reason, it is preferable that the zigzag portions are provided so as to be symmetrical with each other at two locations in the circumferential direction. For example, it is preferable that a zigzag portion is provided in a region where shear deformation occurs. If comprised in this way, the dispersion | distribution of stress can be aimed at easily.

  As described above, according to the present invention, it is possible to easily obtain a drum type washing machine and a door packing capable of realizing low vibration.

1 is a perspective view illustrating an appearance of a drum type washing machine according to an embodiment of the present invention. It is sectional drawing which showed the inside of the drum type washing machine by one Embodiment of this invention. It is sectional drawing which expanded and showed the F section of FIG. It is the front view which looked at the door packing by one Embodiment of this invention from the main body side. FIG. 5 is a perspective view showing a part of a door packing according to an embodiment of the present invention (a view corresponding to the AA portion in FIG. 4). FIG. 5 is a side view showing a part of the door packing according to the embodiment of the present invention (a view corresponding to the AA portion in FIG. 4: a side view seen from a direction substantially perpendicular to the rotation axis). It is the perspective view which showed a part of door packing by a comparative example. It is a figure which shows the calculation model for verifying the effect of vibration reduction. It is sectional drawing which showed the G section of FIG. 8 typically. It is a figure which shows the stress distribution of a door packing, (A) is the stress distribution figure of the door packing by a comparative example, (B) is the stress distribution figure of the door packing by an Example. It is the perspective view which showed the door packing of the drum type washing machine by the 1st modification of this invention. It is the side view which showed the door packing of the drum type washing machine by the 1st modification of this invention. It is the perspective view which showed the door packing of the drum type washing machine by the 2nd modification of this invention. It is the side view which showed the door packing of the drum type washing machine by the 2nd modification of this invention. It is a schematic diagram for demonstrating the deformation | transformation of the door packing at the time of water tank rocking | fluctuation (The figure which showed typically the deformation | transformation of the door packing at the time of water tank rocking | fluctuation).

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an external appearance of a drum type washing machine according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the inside of a drum type washing machine according to an embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of a portion F in FIG. 4-6 is a figure for demonstrating the drum type washing machine and door packing by one Embodiment of this invention. First, a drum type washing machine and a door packing according to an embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the drum type washing machine 1 includes a main body (outer box) 10 that constitutes an external appearance. The main body 10 includes a bottom base 11 and an outer tub 12. On the front surface of the main body 10 (outer tub 12), a circular main body opening 13 (in / out port) for taking in and out the laundry is formed. A circular door 15 that closes the main body opening 13 is provided on the front surface of the main body 10.

  As shown in FIG. 2, a bottomed cylindrical water tank 20 is provided in the main body 10. The water tank 20 is inclined at a predetermined angle (for example, about 10 to 20 °) with respect to the horizontal so that the back side is downward. In the main body 10, the water tank 20 is elastically supported so as to be swingable by a cushioning component including a spring 30 and a damper 35. Specifically, the weight of the water tank 20 is supported by a plurality of dampers 35 from below, and the posture of the water tank 20 is adjusted by a spring 30 provided above. The water tank 20 is formed with a circular water tank opening 21 facing the main body opening 13 on the front surface of the cylindrical shaft.

  A rotating drum 50 that rotates about a rotating shaft 40 that is disposed substantially horizontally is provided inside the water tank 20. The rotating drum 50 has a bottomed cylindrical shape. A drive motor 60 that rotates the rotary drum 50 is connected to the rotary drum 50 at the bottom of the rotary drum 50. The drive motor 60 can rotate forward and backward, and includes a stator and a rotor fixed to the rotary shaft 40. The driving force of the drive motor 60 is transmitted to the rotary shaft 40 through the stator and the rotor. The outer periphery of the drive motor 60 is covered with a motor case 61.

  A large number of small holes (not shown) are formed in the peripheral wall of the rotary drum 50 to communicate the inside and outside. The rotary drum 50 is formed with a circular drum opening 51 facing the water tank opening 21, and a fluid balancer 52 is provided on the outer periphery thereof.

  As described above, both the water tank 20 and the rotary drum 50 are open on the front surface, and each opening is positioned along with the entrance / exit of the main body 10 in the axial direction of the rotary shaft 40.

  A door packing 70 made of rubber or the like is attached around the water tank opening 21. The door packing 70 connects the peripheral edge of the main body opening 13 and the peripheral edge of the water tank opening 21, thereby holding the main body 10 and the water tank 20 watertight.

  As shown in FIGS. 3 and 4, the door packing 70 is formed in a cylindrical shape (annular shape), one end is fixed to the peripheral edge of the entrance / exit (main body opening 13), and the other end is the water tank opening 21. It is being fixed to the peripheral part. Further, as shown in FIG. 5, the door packing 70 has a substantially cylindrical body 71, a bellows part 72 continuing to the other end (water tank 20 side), and a flat part 73.

  The bellows portion 72 is formed in a single bellows that is bent in the axial direction (T direction) in a plane including the central axis of the rotary drum 50 to form a mountain shape, and is expandable and contractable in the radial direction (R direction). . The bellows part 72 is arranged on the outer peripheral side of the body part 71, connects the inner peripheral edge to the body part 71, and is extendable in the axial direction with respect to the body part 71. Thereby, the axial and radial swing of the water tank 2 can be absorbed.

  The flat surface portion 73 of the door packing 70 is formed integrally with the upper portion of the body portion 71. As shown in FIG. 3, the flat surface portion 73 is disposed on the main body 10 side and is fixed to the peripheral edge portion of the main body opening 13.

  As shown in FIGS. 5 and 6, in this embodiment, a zigzag portion 75 is formed in the body portion 71 of the door packing 70. The zigzag portion 75 extends in the circumferential direction (S direction) of the door packing 70 and has a zigzag cross section perpendicular to the axial direction. The zigzag portion 75 is formed in a bowl shape, and the ridge line is along the axial direction (T direction) of the rotation shaft 40. In the present embodiment, the body portion 71 of the door packing 70 is formed in the zigzag portion 75. 5 and 6 show a part (AA portion) of FIG. 4, the zigzag portion 75 may be formed over the entire circumference of the body portion 71. The zigzag portion 75 may be formed in a part of the circumferential direction.

  As described above, at least a part of the body portion 71 of the door packing 70 is a zigzag portion 75, so that the inner peripheral edge of the bellows portion 72 is also connected to the zigzag portion 75. Moreover, since it can also be said that the trunk | drum 71 is a part of the bellows part 72, the zigzag part 75 is formed by changing the shape of a part of bellows part 72 in this case.

  Here, when the water tank 20 swings in the Y direction (Y direction in FIG. 4), for example, when the drum-type washing machine 1 is washed or dehydrated, the fixed end of the door packing 70 to the water tank 20 is displaced in the Y direction. As a result, a shearing force is applied along the circumferential direction at a position shifted in the circumferential direction by ± 90 ° with respect to the displacement direction.

  However, in this embodiment, since the zigzag part 75 is formed in the trunk | drum 71 of the door packing 70, the door packing 70 is easy to expand-contract in the circumferential direction. Therefore, even when the water tank 20 swings in a direction substantially perpendicular (Y direction) to the axial direction (T direction) of the rotary shaft 40 and the door packing 70 undergoes shear deformation, the door packing is protected against the deformation. 70 follows easily. Thereby, since the influence of the swing of the water tank 20 is not easily transmitted to the washing machine body, the body vibration of the drum type washing machine 1 can be reduced.

  In addition, since the door packing 70 also has the bellows part 72, the door packing 70 can also be made to follow the rocking | fluctuation of the water tank 20 easily by this.

  Further, in the present embodiment, the zigzag portion 75 of the door packing 70 is formed in a bowl shape, and the ridgeline thereof is configured along the axial direction (T direction) of the rotating shaft 40, so that the door packing 70 has a circumferential shape. Can be easily expanded and contracted in the direction. For this reason, the influence of the swing of the water tub 20 can be easily prevented from being transmitted to the washing machine body.

  When the zigzag portion 75 of the door packing 70 is formed in a part of the door packing 70 in the circumferential direction, the structure can be simplified in addition to the above effects.

  Therefore, low vibration of the drum type washing machine can be realized by configuring as described above. Moreover, since the zigzag part 75 is formed in the trunk | drum 71 as mentioned above (because the zigzag part 75 is formed by changing the shape of a part of bellows part 72), the structure of a washing machine It is possible to improve the damping performance without changing (without changing the conventional structure). For example, unlike the present embodiment, when the bellows structure for suppressing the vibration in the vertical direction is independently provided on the rotating shaft 40, a space for providing such a bellows structure is required. Therefore, in this case, it is necessary to change the structure of the washing machine. On the other hand, when an independent bellows structure is provided without changing the structure of the washing machine, the bellows structure itself or other portions of the door packing are affected. For this reason, in this case, the vibration control performance decreases. On the other hand, in this embodiment, by configuring the door packing 70 as described above, the vibration damping performance can be improved without changing the structure of the washing machine.

  Next, a computer simulation performed to confirm the effect of this embodiment will be described. FIG. 8 is a diagram showing a calculation model for verifying the effect of vibration reduction. FIG. 9 is a cross-sectional view schematically showing part G of FIG.

  In this computer simulation, the structure (shape) of the door packing according to the above embodiment is an example (see FIG. 5), and the structure (shape) of the door packing without the zigzag portion 75 is a comparative example (see FIG. 7). In the comparative example, the structure (shape) other than the zigzag portion 75 was the same as in the example. Then, as shown in FIG. 8 and FIG. 9, a fixing condition is given to a portion fixed to the opening on the main body side of the door packing, and a displacement (5 mm) simulating swinging is fixed to the portion fixed to the opening on the water tank side. The simulation model using finite element method was performed.

  Since the door packing has an axisymmetric shape, a 1/2 model was used for the calculation. The analysis conditions used were ANSYS static structural analysis. Specific conditions are as follows.

(Analysis conditions)
Material characteristics: Door packing Young's modulus: 300Pa
Poisson's ratio: 0.49 (common)
Water tank / outer tank (main body) Rigid body Restraint condition: Outer tank (main body) Fully fixed Load condition: Water tank displacement 5 mm
(Radiation direction: direction perpendicular to the axis of rotation)
Evaluation: Stress distribution on door packing
Reaction force transmitted to the outer tank (main body)

  Table 1 shows the calculation result of the reaction force value on the main body side (fixed point side).

  In the verification of the effect by simulation, the example and the comparative example were compared using the reaction force value generated on the main body side (fixed point side) as an index indicating the ease of transmission of vibration. It can be said that if the reaction force value is large, vibration is easily transmitted to the main body side, and if the reaction force value is small, it is difficult to transmit vibration to the main body side.

Table 1 shows that the reaction force value of the example having the zigzag portion 75 in the circumferential direction is smaller than that of the comparative example having no zigzag portion 75. Specifically, the reaction force value of the comparative example is 3.96 × 10 ⁻³ N, whereas the reaction force value of the example is 3.80 × 10 ⁻³ N. As a result, the reaction force was reduced by about 4%. From this, it was confirmed that by providing the zigzag portion, the reaction force value decreases, and the structure is such that vibration is not easily transmitted to the main body.

  FIG. 10 is a diagram showing the stress distribution of the door packing. FIG. 10A shows the stress distribution of the door packing according to the comparative example, and FIG. 10B shows the stress distribution of the door packing according to the example. In FIG. 10, only the region (stress concentration portion) where the stress is greater than the predetermined value is shown.

  From FIG. 10, in both the example and the comparative example, the maximum stress distribution region 150 exists at a position shifted by ± 90 ° with respect to the displacement direction. However, in the comparative example, the stress concentration portion 160 (hatching region) is relatively large, whereas in the example, the stress concentration portion 160 (hatching region) is small and dispersed. From this, it was confirmed that by providing the zigzag portion 75 in the circumferential direction, the stress is relieved and the load on the door packing 70 is reduced.

  As described above, in the door packing according to the present embodiment, the bellows portion 75 is continuously formed on the water tank 2 side and the main body 10 side, and the zigzag portion 75 extending in the circumferential direction is further formed. Is further reduced. Thereby, the further vibration reduction of the drum type washing machine is realized.

  From the stress distribution shown in FIG. 10, if at least a zigzag portion is provided in the portion that becomes the maximum stress distribution region 150, the stress can be dispersed and the reaction force value can be lowered. Therefore, in addition to the configuration in which the zigzag portion 75 is provided in the entire circumferential direction, a configuration in which the zigzag portion 75 is provided in a part in the circumferential direction is also effective. In this case, it is preferable that the zigzag portions 75 are provided so as to be symmetrical to each other at two locations in the circumferential direction. Moreover, it is preferable that the one zigzag part 75 is formed in the circumferential direction with the length of about 1/4 to 1/8 of the circumference. Thus, by providing the zigzag portion 75 in a part in the circumferential direction, the structure of the door packing 70 can be simplified in addition to realizing low vibration.

  For example, when the substantially vertical direction of the drum-type washing machine is the Y direction, it is preferable that the zigzag portion 75 is provided at least at a position shifted in the circumferential direction by ± 90 ° with respect to the Y direction. In the case of a drum-type washing machine, the water tank 20 easily swings in the vertical direction (substantially vertical direction (Y direction)) of the main body 10 due to the influence of gravity. Therefore, as described above, the zigzag portion 75 of the door packing 70 is displaced in two circumferential directions by ± 90 ° in the substantially vertical direction (Y direction) of the main body 10 (width direction of the main body 10 (X direction)). Are preferably provided so as to be symmetrical to each other.

(First modification)
11 and 12 are views showing a door packing of a drum type washing machine according to a first modification of the present invention. 11 and 12 show diagrams corresponding to the AA portion of FIG. FIG. 11 is a perspective view, and FIG. 12 is a side view seen from a direction substantially perpendicular to the rotation axis.

  Referring to FIGS. 11 and 12, in the first modification, a zigzag portion 75 provided in the body portion 71 is formed in a wave shape. The wavy zigzag portion 75 is formed such that peaks and valleys extend in the axial direction (T direction) of the rotation shaft 40 and are arranged in the circumferential direction.

  Even when configured in this manner, the same effects as those of the above-described embodiment can be obtained. Moreover, when the same simulation as the said embodiment was performed, the result similar to the said embodiment was obtained.

(Second modification)
13 and 14 are views showing a door packing 70 of a drum type washing machine according to a second modification of the present invention. 13 and 14 show views corresponding to the AA portion of FIG. FIG. 13 is a perspective view, and FIG. 14 is a side view seen from a direction substantially perpendicular to the rotation axis.

  With reference to FIG. 13 and FIG. 14, in the second modification, a zigzag portion 75 provided in the body portion 71 is configured to include a concave portion 175 having a U-shaped cross section. The recess 175 is formed so as to extend in a direction inclined with respect to the axial direction (T direction) of the rotating shaft or in the axial direction (T direction) of the rotating shaft. Note that the number of the recesses 175 constituting the zigzag portion 75 may be one or more. Even when configured in this manner, the same effects as those of the above-described embodiment can be obtained.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example in which the ridge line of the bowl-shaped zigzag portion 75 is configured to be along the axial direction of the rotation axis is shown. However, the present invention is not limited thereto, and the ridge line of the zigzag portion 75 is the axis of the rotation axis. You may be comprised along the direction which inclines with respect to a direction.

  Moreover, although the example which formed the zigzag part 75 of the door packing 70 in the shape of a hook or a wave was shown in the said embodiment, this invention is not limited to this, The zigzag part 75 of the door packing 70 relieves a shear stress. Any other configuration may be used as long as it is zigzag.

DESCRIPTION OF SYMBOLS 10 Main body 11 Base 12 Outer tank 13 Main body opening part 15 Door 20 Water tank 21 Water tank opening part 30 Spring 35 Damper 40 Rotating shaft 50 Rotating drum 51 Drum opening part 52 Fluid balancer 60 Drive motor 61 Motor case 70 Door packing 71 Body part 72 Bellows part 73 Flat part 75 Zigzag part 150 Maximum stress distribution area 160 Stress concentration part 175 Concave part

Claims (8)

A main body having a front / rear opening for taking in and out the laundry;
A water tank that is swingably attached in the main body and has an opening on the front surface;
A rotating drum that is built in the water tank and rotates around a rotating shaft inclined at a predetermined angle and has an opening on the front surface;
Driving means for driving the rotating shaft;
An annular door packing having one end fixed to the peripheral edge of the outlet and the other end fixed to the peripheral edge of the opening of the water tank;
The door packing has a zigzag portion having a zigzag cross section extending in the circumferential direction and perpendicular to the axial direction.   2. The drum type washing machine according to claim 1, wherein the zigzag portion of the door packing is formed in a bowl shape, and the ridgeline thereof is configured along the axial direction of the rotation shaft.   The drum-type washing machine according to claim 1, wherein the zigzag portion of the door packing is formed in a wave shape.   The drum type washing machine according to any one of claims 1 to 3, wherein the zigzag portion of the door packing is formed in a part of a circumferential direction of the door packing. The door packing has a single bellows part bent in the direction of the rotation axis to form a mountain shape,
The drum-type laundry according to any one of claims 1 to 4, wherein the bellows part is arranged on an outer peripheral side of the zigzag part, and an inner peripheral edge thereof is connected to the zigzag part. Machine.   The zigzag portion of the door packing is provided so as to be symmetrical to each other at two positions shifted in a circumferential direction of ± 90 ° with respect to a substantially vertical direction of the main body. The drum type washing machine of any one of -5.   A door packing having a substantially cylindrical shape and a zigzag portion having a zigzag cross-sectional shape perpendicular to the cylindrical axis provided on a peripheral surface.   The door packing according to claim 7, wherein the zigzag portion extends in the circumferential direction and is provided so as to be symmetrical with each other at two locations on the circumferential surface.