JP5214403B2 - Rotating damper - Google Patents

Description

  The present invention is provided between a toilet body and a toilet body such as a toilet lid and a rotating body rotatably supported by the toilet body, and prevents the rotating body from rotating at least in one direction and rotates at a low speed. It relates to a rotating damper.

  Generally, this type of rotary damper has a bottomed cylindrical damper body, a rotor rotatably provided at the end of the damper body on the opening side, and an axial movement inside the damper body. And a non-rotatable piston and a moving mechanism for moving the piston as the rotor rotates. The interior of the damper main body located between the rotor and the bottom is partitioned by a piston into a first chamber on the bottom side and a second chamber on the rotor side. The first and second chambers are filled with a fluid such as a viscous fluid.

  When the rotor rotates in one direction, the piston moves from the first chamber side to the second chamber side. Then, the fluid in the second chamber tends to flow into the first chamber through the communication path. However, at this time, the communication path is closed by the valve body. For this reason, high-speed rotation of the rotor is prevented and the rotor rotates at a low speed. When the rotor rotates in the other direction, the piston moves from the second chamber side to the first chamber side, and the fluid in the first chamber tends to flow into the second chamber. At this time, the valve body opens the communication path. Therefore, the fluid in the first chamber can flow into the second chamber through the communication passage with almost no resistance. Therefore, the rotor can rotate at a high speed.

  In the conventional rotary damper, as described in Patent Document 1 below, the valve body is formed in a ring shape and is mounted in an annular groove formed in the outer peripheral surface of the piston. When the valve body is mounted in the annular groove, the piston is inserted into the valve body from one end thereof. When the valve body faces the annular groove, the piston is rotated by approximately 90 ° with respect to the valve body. As a result, the valve body is attached to the annular groove of the piston so as to be movable within a predetermined range between the open position and the closed position.

Japanese Patent No. 4064235

  In the conventional rotary damper, when the valve body is mounted in the annular groove, the piston must be inserted into the valve body. In this case, there is no problem as long as the outer diameter of the piston is significantly larger than the inner diameter of the valve body. However, the outer diameter of the piston and the inner diameter of the valve body are substantially the same and are non-circular. For this reason, there was a problem that it was difficult to insert the piston into the valve body. In addition, in order to regulate the movement range of the piston, the piston has to be rotated by 90 °, and there is a problem that it takes time and effort.

In order to solve the above-described problem, the present invention is provided with a damper main body having a housing portion whose one end is open and the other end is closed by a bottom portion, and rotatably provided at the opening side end portion of the housing portion. A rotor, a fluid filled in the housing portion between the rotor and the bottom portion, and a movable portion in the axial direction in the housing portion between the rotor and the bottom portion, and non-rotatable. A piston that divides the interior of the housing portion into a first chamber on the bottom side and a second chamber on the rotor side, a moving mechanism that moves the piston with rotation of the rotor, and the housing portion on the piston The valve body is provided so as to be movable between a closed position and an open position in the axial direction of the first chamber, and between the inner peripheral surface of the housing portion and the outer peripheral surface of the piston, A communication passage that communicates with the second chamber is provided; When the valve is located at the closed position, the communication passage is closed by the valve body, and when the valve body is located at the open position, a mounting recess is formed on the outer peripheral surface of the piston in the rotary damper that opens the communication passage. The valve body is mounted on the mounting recess so as to be detachable in the radial direction of the piston and movable in the axial direction of the piston, and the valve body is positioned on one end side in the axial direction of the piston. When closing the first side, the communication path is closed at the closed position, and when the second side of the mounting recess is positioned at the other end in the axial direction of the piston, the open position is reached. open the aforementioned connecting channel is located, in the valve body, via a facing surface that bottom facing the mounting recess from the second contact surface which abuts on the second side when positioned in the open position A communication groove extending to the first contact surface that abuts against the first side surface when the valve body is in the closed position is formed, and when the valve body is in the open position, the communication chamber has a first chamber side. And the second chamber side portion communicate with each other through the communication groove and a gap formed between the first side surface and the first contact surface, and the valve body is in the closed position. When located, the communication groove is closed by the first contact surface and the first side surface where the communication grooves abut each other. As a result, the communication path is closed by the valve body, and the first contact surface and the first side are closed. The side surface is formed with a pressing surface that presses the valve body outward in the radial direction of the piston by abutting each other to press-contact the valve body against the inner peripheral surface of the housing portion .

  According to the present invention having the above-described characteristic configuration, when the valve body is mounted on the piston, it is only necessary to move the valve body from the radially outer side to the inner side of the piston and insert it into the mounting recess. Therefore, the valve body can be easily attached to the piston.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of the present invention. The rotary damper 1 of this embodiment includes a casing (damper body) 2, a rotor 3, a cam member 4, a piston 5 and a valve body 6 as main components.

  As shown in FIGS. 1 and 5, the casing 2 has one end (hereinafter referred to as a front end) opened and the other end (hereinafter referred to as a rear end) having a bottom 2 a. It is formed in a bottomed cylindrical shape. The inside of the casing 2 is an accommodation hole (accommodating portion) 2b. The casing 2 may be one in which the housing hole 2b is formed in the block body without being formed into a cylindrical shape.

  A pair of first flat portions 2 c and 2 c are formed on the outer peripheral surface of the casing 2. The pair of first flat portions 2 c and 2 c are arranged 180 degrees apart in the circumferential direction of the casing 2. Further, each first flat portion 2 c extends from the intermediate portion thereof to the rear end surface along the longitudinal direction of the casing 2. The first flat portions 2c and 2c are formed by crushing the peripheral wall portion of the casing 2 inward in the radial direction. As a result, first flat surface portions 2d and 2d corresponding to the first flat portions 2c and 2c are formed on the inner peripheral surface of the accommodation hole 2b. The first flat portions 2d and 2d are arranged so as to circumscribe a circle centered on the axis of the casing 2.

  A pair of second flat portions 2 e and 2 e are formed on the outer peripheral surface of the casing 2. The pair of second flat portions 2e and 2e are disposed 180 ° apart in the circumferential direction of the casing 2 and 90 ° apart from the pair of first flat portions 2c and 2c in the circumferential direction. The second flat portions 2e and 2e are arranged at substantially the same position as the first flat portions 2c and 2c in the longitudinal direction of the casing 2, and extend from the intermediate portion to the rear end surface along the longitudinal direction of the casing 2. ing. The 2nd flat part 2e is formed by crushing the surrounding wall part of the casing 2 to the radial direction inner side. As a result, second flat surface portions 2f and 2f corresponding to the second flat portions 2e and 2e are formed on the inner peripheral surface of the accommodation hole 2b. The second flat portions 2 f and 2 f are arranged so as to circumscribe a circle centered on the axis of the casing 2. Moreover, the diameter of the circle circumscribing the second plane portion 2f is set larger than the diameter of the circle circumscribing the first plane portion 2d.

  The rotor 3 has a large-diameter portion 3a, a medium-diameter portion 3b, and a small-diameter portion 3c that are integrally formed with their axes aligned. The large-diameter portion 3a and the medium-diameter portion 3b are inserted into end portions on the opening side of the accommodation hole 2b. The large-diameter portion 3a is fitted to the inner peripheral surface of the accommodation hole 2b so as to be directly rotatable. The middle diameter portion 3b is rotatably fitted to the inner peripheral surface of the accommodation hole 2b via the cylinder 7 fitted therein. In this way, the rotor 3 is rotatably fitted to the casing 2. The rotor 3 may be rotatably fitted to the casing 2 in another form. A seal member 8 made of an O-ring or the like is mounted between the large diameter portion 3a and the cylindrical body 7. The seal member 8 seals between the inner peripheral surface of the accommodation hole 2 b and the outer peripheral surface of the rotor 3. Further, the cylindrical body 7 abuts against a reduced diameter portion 2 g formed at the opening side end portion of the casing 2 through a washer 9. Therefore, the rotor 3 does not move in the direction from the bottom 2a of the accommodation hole 2b toward the opening. The small diameter portion 3c is projected from the casing 2 to the outside. The accommodation hole 2b between the large diameter portion 3a and the bottom portion 2a of the rotor 3 is filled with a viscous fluid or other fluid (not shown).

  When the rotary damper 1 is provided, for example, between the toilet body of the toilet bowl and the toilet lid, one of the casing 2 and the small diameter portion 3c of the rotor 3 is non-rotatably connected to the toilet body, and the other is the toilet bowl. It is non-rotatably connected to the lid. Of course, the rotary damper 1 can also be used between a toilet body other than the toilet body and the toilet lid, and a rotating body provided rotatably therewith.

The cam member 4 has a cam portion 4a and a connecting shaft portion 4b which are integrally formed with their axes aligned. The cam portion 4a is inserted into an end portion on the bottom portion 2a side of the accommodation hole 2b. The outer peripheral surface of the cam portion 4a is in contact with the first flat surface portions 2d and 2d so as to be rotatable. Thereby, the cam member 4 is rotatably accommodated in the accommodation hole 2b in a state in which the axis thereof coincides with the axis of the accommodation hole 2b. Further, the cam portion 4a is in contact with the bottom portion 2a. Therefore, the cam member 4 does not move in the direction from the opening of the accommodation hole 2b toward the bottom 2a. The connecting shaft portion 4b extends on the axis of the accommodation hole 2b from the bottom portion 2a side toward the opening portion side, and the tip portion thereof is in an engagement hole 3d formed on the end surface of the large diameter portion 3a of the rotor 3. Inserted non-rotatably. Therefore, the cam member 4 rotates integrally with the rotor 3 about the axis of the cylinder 2.
Rotates together.

  The piston 5 has substantially the same cross-sectional shape and dimensions as the portion of the inner peripheral surface of the accommodation hole 2b where the first and second flat surface portions 2d and 2f are formed. That is, the piston 5 has an axial shape and has an outer diameter that is substantially the same as the inner diameter of the accommodation hole 2b. On the outer peripheral surface of the piston 5, third flat portions 5a and 5a extending from one end surface to the other end surface are formed. The third plane portions 5a and 5a have the same width as the first plane portions 2d and 2d. And the piston 5 is inserted in the accommodation hole 2b so that the 3rd plane parts 5a and 5a may oppose the 1st plane parts 2d and 2d. Thereby, the piston 5 is fitted in the accommodation hole 2b so as to be slidable and non-rotatable. A through-hole 5b extending from one end surface to the other end surface on the axis is formed in the central portion of the piston 5. The connecting shaft portion 4b is inserted into the through hole 5b so as to be rotatable and slidable. A space between the inner peripheral surface of the through hole 5b and the outer peripheral surface of the connecting shaft portion 4b is sealed with a seal member 10 made of an O-ring or the like.

  By fitting the piston 5 into the accommodation hole 2b, the interior of the accommodation hole 2b is divided into a first chamber 11 on the bottom 2a side and a second chamber 12 on the rotor 3 side. The first chamber 11 and the second chamber 12 are communicated by communication passages 13 and 13. The communication passage 13 is constituted by a passage groove 13a formed on the outer peripheral surface of the piston 5 and a second flat portion 2f. The passage groove 13a extends from one end surface of the piston 5 to the other end surface. Accordingly, one end of the passage groove 13 a communicates with the first chamber 11, and the other end of the passage groove 13 a communicates with the second chamber 12. The width of the passage groove 13a is set to be the same as the width of the second flat portion 2f, and the open portion of the passage groove 13a facing the radially outer side of the piston 5 is shielded by the second flat portion 2f. As a result, the passage groove 13a and the second flat surface portion 2f form a communication passage 13 that communicates the first chamber 11 and the second chamber 12.

  The communication path 13 can also employ other structures. For example, without forming the second flat surface portion 2f on the inner peripheral surface of the receiving hole 2b, the inner peripheral surface of the receiving hole 2b is left as it is in the portion where the second flat surface portion 2f is formed, and the portion is arc-shaped in cross section To. On the other hand, a flat portion extending from one end surface of the piston 5 to the other end surface is formed in a portion of the outer peripheral surface of the piston 5 where the passage groove 13a is formed. A space surrounded by the flat portion and the inner peripheral surface of the accommodation hole 2b can be used as a communication path.

  An end surface cam 14a and an end surface cam 14b that are in contact with each other are formed on the opposing surfaces of the large-diameter portion 3a of the rotor 3 and the piston 5, respectively. The end cams 14a and 14b constitute a first cam mechanism 14. The first cam mechanism 14 moves the piston 5 in the direction from the second chamber 12 toward the first chamber 11 when the rotor 3 rotates in the first direction. Conversely, when the rotor 3 rotates in the second direction that is opposite to the first direction, the piston 5 is allowed to move in the direction from the first chamber 11 toward the second chamber 12.

  End cams 15 a and 15 b that are in contact with each other are formed on the opposing surfaces of the cam portion 4 a and the piston 5 of the cam member 4. The end cams 15a and 15b constitute a second cam mechanism 15. The second cam mechanism 15 allows the piston 5 to move in a direction from the second chamber 12 toward the first chamber 11 when the rotor 3 rotates in the first direction. Conversely, when the rotor 3 rotates in the second direction, the piston 5 is moved in the direction from the first chamber 11 to the second chamber 12. Moreover, the first and second cam mechanisms 14 and 15 are set so that the moving distance of the piston 5 per unit rotation angle of the rotor 3 is the same. Therefore, when the rotor 3 rotates in the first or second direction, the piston 5 follows the axis and moves in the axial direction of the accommodation hole 2b. As is apparent from this, in this embodiment, the first and second cam mechanisms 14 and 15 constitute a moving mechanism. In addition, about any one of the 1st, 2nd cam mechanisms 14 and 15, you may replace with it and may use biasing means, such as a coil spring.

  The piston 5 is provided with the valve body 6 in order to allow the rotor 3 to rotate at a high speed in the second direction while preventing the high-speed rotation in the first direction and causing the rotor 3 to rotate at a low speed. That is, two mounting recesses 5 c are formed on the outer peripheral surface of the piston 5. The two mounting recesses 5 c and 5 c are arranged 180 ° apart in the circumferential direction of the piston 5. Each mounting recess 5c extends along the string of the piston 5 and is disposed so as to be orthogonal to the passage groove 13a. The length of the mounting recess 5c is set longer than the width of the passage groove 13a and crosses the passage groove 13a. Further, the depth of the mounting recess 5c is set deeper than the depth of the passage groove 13a. By forming such a mounting recess 5c, the passage groove 13a (communication passage 13) is divided into a first passage portion 13b on the first chamber 11 side and a second passage portion 13c on the second chamber 12 side. ing.

  A valve body 6 is mounted in the mounting recess 5c. The valve body 6 is mounted before the piston 5 is inserted into the casing 2, and can be mounted in the mounting recess 5 c simply by moving the piston 5 in the radial direction. As shown in FIG. 3, the valve body 6 is immovable in the longitudinal direction of the mounting recess 5 c because both end surfaces in the longitudinal direction abut against both end surfaces in the longitudinal direction of the mounting recess 5 c. On the other hand, as apparent from FIGS. 2 and 4, the width of the valve body 6 (the width in the axial direction of the piston 5) is shorter than the width of the mounting recess 5c, and the valve body 6 is mounted by the difference. The recess 5c is movable in the width direction. Further, as is apparent from FIG. 3, the thickness of the valve body 6 in the radial direction of the piston 5 is thinner than the depth of the mounting recess 5c, and the valve body 6 has a depth of the mounting recess 5c corresponding to the difference. It can move in the direction (the radial direction of the piston 5). The thickness of the valve body 6 may be the same as the depth of the mounting recess 5c, and the valve body 6 may be immovable in the depth direction of the mounting recess 5c.

  Of the both side surfaces 5d and 5e in the width direction of the mounting recess 5c, the side surface (second side surface) 5d on the first chamber 11 side is constituted by a plane whose angle with the axis of the piston 5 is a right angle. On the other hand, the side surface (first side surface; pressing surface) 5e on the second chamber 12 side is inclined so that the width of the mounting recess 5c increases from the bottom surface of the mounting recess 5c toward the radially outer side of the piston 5. . However, the side surface 5e is not necessarily inclined, and the angle formed with the axis of the piston 5 may be 90 °.

  A communication groove 6 a is formed in the valve body 6. The communication groove 6a includes a side surface (second abutting surface; pressing surface) 6b of the valve body 6 facing the side surface 5d of the mounting recess 5c and a lower surface (facing surface) 6c of the valve body 6 facing the bottom surface of the mounting recess 5c. Is formed over. One end of the communication groove 6a reaches the upper surface 6e of the valve body 6 in contact with the inner peripheral surface of the accommodation hole 2b. The other end of the communication groove 6 reaches the side surface (first contact surface) 6d of the valve body 6 that crosses the side surface 6b and the lower surface 6c and abuts against the side surface 5e. The width of the communication groove 6 a is set to be shorter than the length of the valve body 6, and is disposed in the middle portion of the valve body 6 in the longitudinal direction. The side surface 6d of the valve body 6 is an inclined surface that is inclined at the same angle as the side surface 5e, but when the side surface 5e is a vertical surface having an angle of 90 ° with the axis of the piston 5, The side surface 6d is also a vertical surface.

  As shown in FIG. 2, when the valve body 6 is in contact with the inclined side surface 5e of the mounting recess 5c, one end portion of the communication groove 6a communicates with the first passage portion 13b of the passage groove 13a. An open portion of the side surface 6d of the communication groove 6a is closed by side surfaces 5e and 6d that abut each other. As a result, the first and second passage portions 13 b and 13 c are closed by the valve body 6, and consequently, the space between the first chamber 11 and the second chamber 12 is closed by the valve body 6. As is clear from this, the position of the valve body 6 when the side surface 6d is in contact with the side surface 5e is the closed position.

  As shown in FIG. 4, when the side surface 6b of the valve body 6 is in contact with the side surface 5d of the mounting recess 5c, one end portion of the communication groove 6a communicates with the first passage portion 13b and the other end portion of the communication groove 6a. Communicates with the second passage portion 13c through a gap S formed between the side surfaces 5e and 6d. As a result, the first and second passage portions 13b and 13c communicate with each other via the communication groove 6a, and as a result, the first groove 11 and the second chamber 12 communicate with each other via the communication passage 13 and the communication groove 6a. As is clear from this, the position of the valve body 6 when the side surface 6b is in contact with the side surface 5d is the open position.

  When assembling the rotary damper 1 having the above configuration, the cam member 4, the piston 5, and the rotor 3 are sequentially inserted into the housing hole 2 b of the casing 2. In this case, the valve body 6 is attached to the piston 5 before insertion into the accommodation hole 2b. When the valve body 6 is mounted on the piston 5, it is only necessary to move the valve body 6 from the outside of the piston 5 in the radial direction and insert it into the mounting recess 5c. Therefore, the valve body 6 can be easily mounted on the piston 5 as compared with a conventional rotary damper in which the valve body is mounted on the piston by inserting the piston into the annular valve body and rotating it 90 °. Moreover, since the valve body 6 is not annular, it is significantly smaller than the annular valve body.

  In the rotary damper 1 configured as described above, it is assumed that the valve body 6 is now located at the closed position shown in FIG. When the rotor 3 is rotated in the second direction, the piston 5 is moved from the first chamber 11 side to the second chamber 12 side by the second cam mechanism 15. Then, the fluid in the second chamber 12 tends to flow into the first chamber 11 through the communication path 13. At this time, the fluid in the second chamber 12 flows into the mounting recess 5c through the second passage portion 13c. The fluid flowing into the mounting recess 5c hits the side surface 6d of the valve body 6 and moves the valve body 6 from the closed position to the open position. As a result, the second chamber 12 communicates with the first chamber 11 via the communication path 13 and the communication groove 6a. Therefore, the fluid in the second chamber 12 can flow into the first chamber 11 through the communication passage 13 and the communication groove 6a with almost no resistance. Therefore, the rotor 3 can rotate at high speed in the second direction.

  When the rotor 3 is rotated in the first direction in a state where the valve body 6 is located at the open position shown in FIG. 4, the piston 5 is moved from the second chamber 12 side to the first chamber 11 side by the first cam mechanism 14. Moved. Then, the fluid in the first chamber 11 tends to flow into the second chamber 12 through the communication path 13. At this time, the fluid in the first chamber 11 flows into the mounting recess 5c through the first passage portion 13b, but the fluid that has flowed into the mounting recess 5c hits the side surface 6b of the valve body 6 and causes the valve body 6 to move. Move from the open position to the closed position. As a result, the communication groove 6 a is closed, and consequently the communication path 13 is closed by the valve body 6. For this reason, the fluid in the first chamber 11 enables the movement of the piston 5 in the slight gap between the outer peripheral surface of the piston 5 and the inner peripheral surface of the accommodation hole 2b, that is, in the axial direction of the accommodation hole 2b. Flows into the second chamber 12 through the gap for the purpose. However, the gap is very narrow, and the flow resistance to the fluid in the gap is very large. For this reason, high speed rotation of the rotor 3 in the first direction is prevented, and the rotor 3 rotates at low speed. In addition, when the inclined side surface 6d abuts against the side surface 5e, the valve body 6 is pressed outward in the radial direction of the piston 5, and the upper surface 6e of the valve body 6 is pressed into contact with the inner peripheral surface of the accommodation hole 2b. As a result, the circumferential length of the gap formed between the outer peripheral surface of the piston 5 and the inner peripheral surface of the accommodation hole 2b is the length of the valve body 6 (the length in the circumferential direction of the piston 5). Only smaller. Therefore, the rotational speed of the rotor 3 in the first direction can be further reduced.

In addition, this invention is not limited to said embodiment, In the range which does not deviate from the summary, it can change suitably.
For example, in the above embodiment, when the piston 5 moves from the second chamber 12 side to the first chamber 11 side, the valve body 6 is configured to be in the closed position. Conversely, when the piston 5 moves from the first chamber 11 side to the second chamber 12 side, the valve body 6 may be positioned at the open position. In the case of such a configuration, the side surfaces 5d and 5e of the mounting recess 5c are disposed opposite to each other in the axial direction of the piston 5, and the side surfaces 6b and 6d of the valve body 6 are also disposed opposite to each other.

It is a longitudinal cross-sectional view which shows one embodiment of this invention. It is an enlarged view of the X circle part of Drawing 1 shown in the state where a valve element was located in a closed position. It is sectional drawing which follows the XX line of FIG. It is an enlarged view of the X circle part of Drawing 1 shown in the state where a valve element was located in an open position. It is a disassembled perspective view of the same embodiment.

Explanation of symbols

S Gap 1 Rotating damper 2 Casing (damper body)
2a bottom 2b accommodation hole (accommodation part)
3 Rotor 5 Piston 5c Mounting recess 5d Side surface (second side surface)
5e Side surface (first side surface; pressing surface)
6 Valve body 6a Communication groove 6b Side surface (second contact surface)
6c Bottom surface (opposite surface)
6d side surface (first contact surface; pressing surface)
11 1st chamber 12 2nd chamber 13 Communication path 13b 1st channel | path part (the part by the side of the 1st chamber of a communication path)
13c 2nd channel | path part (the part by the side of the 2nd chamber of a communicating path)
14 First cam mechanism (moving mechanism)
15 Second cam mechanism (moving mechanism)

Claims (1)

One end of the damper body having a receiving portion that is open and the other end closed by a bottom portion, a rotor that is rotatably provided at an end portion on the opening side of the receiving portion, and the above-described portion between the rotor and the bottom portion A fluid filled in the accommodating portion and the accommodating portion between the rotor and the bottom portion are provided so as to be movable in the axial direction and non-rotatable, and the inside of the accommodating portion is a first chamber on the bottom side. And a piston that is divided into the rotor-side second chamber, a moving mechanism that moves the piston as the rotor rotates, and the piston between the closed position and the open position in the axial direction of the housing portion. A valve body provided in a movable manner, and a communication path is provided between the inner peripheral surface of the housing portion and the outer peripheral surface of the piston to communicate the first chamber and the second chamber; When the valve body is located at the closed position, the communication path is Closed by the body, when the valve body is positioned in the open position, the rotary damper in which the communication passage is opened,
A mounting recess is formed in the outer peripheral surface of the piston, and the valve body is mounted in the mounting recess so as to be detachable in the radial direction of the piston and movable in the axial direction of the piston. Of the mounting recess located on the other end side in the axial direction of the piston, closing the communication path when the first side surface of the mounting recess positioned on one end side in the axial direction of When it hits the second side surface, it is located at the open position and opens the communication path ,
The valve body includes the first side surface when the valve body is located at the closed position through a facing surface facing the bottom surface of the mounting recess from a second contact surface that abuts against the second side surface when the valve body is located at the open position. When the communication groove extending to the first abutting surface that strikes the valve is formed and the valve body is located at the open position, the first chamber side portion and the second chamber side portion of the communication path are When the valve body is located at the closed position, the communication grooves abut against each other through the communication groove and a gap formed between the first side surface and the first contact surface. Closed by the first contact surface and the first side surface, and as a result, the communication path is closed by the valve body;
On the first contact surface and the first side surface, there is a pressing surface that presses the valve body outward in the radial direction of the piston by abutting against each other and presses the valve body against the inner peripheral surface of the housing portion. A rotary damper characterized by being formed .

Images