JP2009024818A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate orifice formation and adjustment without directly forming the orifice at a piston side. <P>SOLUTION: A shock absorber 1 comprises a cylinder 3 having a fluid chamber inside, a piston 5 movably disposed in the fluid chamber 11 of the cylinder 3 to partition the fluid chamber 11 into a pressure chamber 15 side and a non-pressure chamber 17 side, and a passage 25 provided in the piston 5 to connect the pressure chamber 15 side with the non-pressure chamber 17 side. A valve body 33 is disposed in the pressure chamber 17 side to open and close the passage 25 by approach/separation to/from the piston 5 according the movement of the piston 5. A spacer 35 is disposed between the piston 5 and the valve body 33 to form the orifice 34 between the pressure chamber 15 and the passage 25 in a closed state of the passage 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shock absorber.

  As a conventional shock absorber, for example, a valve body is slidably inserted into a guide bar projecting from a piston, and a flow path that connects the pressure chamber side and the non-pressure chamber side by movement of the valve body is provided. Some are configured to open and close.

  In such a shock absorber, an orifice that communicates a flow path and a pressure chamber is formed in a piston so as to obtain a desired damper effect.

  However, in the above structure, when the orifice is small, it is difficult to form the work. Further, since the orifice is set according to the target damper effect when the piston is processed, it is difficult to adjust the size after the processing.

JP2000-265738

  The problem to be solved is that it is difficult to form and adjust the orifice.

  In order to facilitate the formation and adjustment of the orifice, the present invention includes a piston that is movably disposed in a fluid chamber of a cylinder and divides the fluid chamber into a pressure chamber side and a non-pressure chamber side, and the pressure chamber side A shock absorber having a flow path communicating with the non-pressure chamber side is provided with a valve element that is disposed on the pressure chamber side and closes and separates from the piston in accordance with the movement of the piston to open and close the flow path. The valve body is disposed between the piston and the valve body, and is provided with a spacer that forms an orifice between the pressure chamber and the flow path when the flow path is closed, or without providing a spacer. The main feature is that an orifice is formed between the outer periphery of the valve body and the opening of the flow path at the closed position.

  The shock absorber of the present invention is provided with a spacer that forms an orifice between the pressure chamber and the flow path when the flow path is closed, or between the outer periphery of the valve body and the flow path at the closed position of the valve body. A predetermined damper effect can be obtained by forming an orifice between the opening and the opening. Therefore, the orifice can be easily formed without directly forming the orifice on the piston side.

  Moreover, by changing the shape of the spacer or the valve body, the orifice can be easily adjusted, and the damper effect can be easily adjusted.

  The purpose of facilitating the formation and adjustment of the orifice was realized without directly forming the orifice on the piston side.

  1 to 6 show a shock absorber according to a first embodiment of the present invention, FIG. 1 is a sectional view of the shock absorber, FIG. 2 is an enlarged sectional view of a piston shown in FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view showing a connecting portion of the piston rod shown in FIG. 1, FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 1, and FIG. It is sectional drawing in the VI-VI line arrow of 1.

[Composition of shock absorber]
As shown in FIGS. 1 to 6, the shock absorber 1 generally includes a cylinder 3, a piston 5, a bellows 7, and a coil spring 9 as an elastic member.

  The cylinder 3 has a fluid chamber 11 defined therein by the bellows 7. In the fluid chamber 11, a piston 5 having a flow path 25 is movably disposed via a piston rod 13, and is partitioned into a pressure chamber 15 side and a non-pressure chamber 17 side. A coil spring 9 that urges the piston 5 toward the non-pressure chamber 17 is disposed in the pressure chamber 15. In this embodiment, a valve body 33 is provided which is disposed on the pressure chamber 15 side, closes and separates from the piston 5 according to the movement of the piston 5 and opens and closes the flow path 25. A spacer 35 is provided between the pressure chamber 15 and the flow path 25 when the flow path 25 is closed.

  As shown in FIG. 1, the cylinder 3 has a cylindrical shape with an open end closed by a cylinder cap 19. Inside the cylinder 3, a large diameter portion 21 is formed on the opening end side, and a small diameter portion 23 having a smaller diameter than the large diameter portion 21 is formed on the closed end side. The large diameter portion 21 and the small diameter portion 23 communicate with each other so as to form a stepped portion 24 therebetween.

  A bellows 7 to be described later is disposed in the large-diameter portion 21, and a fluid chamber 11 in which a viscous fluid such as silicon oil is sealed from the bellows 7 to the closed end side, and an air chamber is defined on the open end side. A cylindrical spring seat 28 protruding from the inner end surface 26 on the closed end side of the cylinder 3 is provided in the small diameter portion 23.

  As shown in FIGS. 1 to 3, the piston 5 is disposed in the small diameter portion 23 of the cylinder 3 and is formed in a cylindrical shape having substantially the same cross section as the small diameter portion 23. The piston 5 is provided with a plurality of flow paths 25 penetratingly formed along the axial direction. In the present embodiment, for example, six flow paths 25 are provided at predetermined intervals in the circumferential direction. The flow path 25 communicates with the pressure chamber 15 and the non-pressure chamber 17 of the cylinder 3 and allows the viscous fluid to flow between them. One channel 25 is formed with a larger diameter than the other channels 25, and the flow rate is adjusted.

  A cylindrical guide bar 27 protrudes from the piston 5 on the pressure chamber 15 side. A plate-like spring receiver 29 is fixed to the front end side of the guide bar 27 in an inserted state. From one side of the spring receiver 29, a tip 31 of the inserted guide bar 27 protrudes. A plate-like valve body 33 is provided between the other side of the spring receiver 29 and the piston 5.

  The valve element 33 is inserted through the guide bar 27 so as to be movable in the axial direction. The valve body 33 can open and close the flow path 25 by moving close to and away from the piston 5. The valve element 33 is urged toward the piston 5 by a coil spring 40 installed between the spring receiver 29 and the other side.

  A plate-like spacer (shim) 35 is disposed between the valve element 33 and the piston 5. The spacer 35 is interposed between the piston 5 and the valve element 33 when the valve element 33 is closed, and forms a gap d corresponding to the plate thickness. Further, the spacer 35 partially closes the flow path 25.

  That is, in the closed state of the valve body 33, the flow path 25 partially closed by the spacer 35 communicates with the pressure chamber 15 through the gap d, thereby forming an orifice 34 and obtaining a predetermined damper effect. It is supposed to be.

  Therefore, in this embodiment, the gap d is adjusted by changing the plate thickness of the spacer 35, and the opening amount of the flow path 25 is adjusted by changing the diameter of the spacer 35, so that the opening area and flow rate of the orifice 34 are adjusted. Can be adjusted. Further, the opening area of the orifice can be adjusted by changing the diameter of the flow path 25 on the piston 5 side together with the shape change of the spacer 25 or without changing the shape of the spacer 25.

  A recess 37 is provided on the non-pressure chamber 17 side of the piston 5. The recess 37 engages with the inner end 39 of the piston rod 13. An annular wall 41 is erected around the recess 37.

  The piston rod 13 is divided and formed in the cylinder 3 in the axial direction, and includes a first rod portion 43 on one end side and a second rod portion 45 on the other end side. The first rod portion 43 has a tip that is an inner end portion 39 of the piston rod 13 having a small diameter via a stepped portion 47. As shown in FIG. 4, a connecting recess 49 along the axial direction is provided at the base end of the first rod portion 43. In the connection recess 49, a protrusion 50 is formed in a circular shape.

  The second rod portion 45 is provided with a connecting convex portion 51 that engages with a connecting concave portion of the first rod portion 43 at the tip. The connection convex portion 51 is formed with a circular groove 53 corresponding to the projection 50 of the connection concave portion 49, and is engaged with the connection concave portion 49 so as to be rotatable around the axis. Accordingly, the first rod portion 43 and the second rod portion 45 are connected to each other so as to be relatively rotatable around the axis via the connection recess 49 and the connection protrusion 51. The proximal end side of the second rod portion 45 is drawn out of the cylinder 3 through the insertion hole 55 of the cylinder cap 19. Therefore, the piston rod 13 absorbs the rotational force around the axis applied outside the cylinder 3 by rotating the second rod portion 45 and the first rod portion 43 relative to each other, and transmits it to the inside of the cylinder 3. It can be suppressed.

  The bellows 7 is made of an elastically deformable material such as rubber as shown in FIG. The bellows 7 is composed of an outer cylinder portion 57 on one side and an inner cylinder portion 59 on the other side, and the inner end portion of the piston rod 13 which is configured on the piston 5 side with the inner peripheral surface 61 of the large diameter portion 21 of the cylinder 3. 39.

  The outer cylinder portion 57 is disposed on the inner peripheral surface 61 side of the large diameter portion 21. The outer cylinder portion 57 extends from the end portion 63 toward the open end side of the cylinder 3 so as to gradually become a smaller diameter. The inner cylinder portion 59 is disposed inside the outer cylinder portion 57 via the folded portion 65. The inner cylinder portion 59 extends along the piston rod 13, and the end portion 67 reaches the outer periphery of the inner end portion 39 of the piston rod 13.

  The bellows 7 communicates with the non-pressure chamber 17 between the inner and outer cylinders 57 and 59 and is elastically deformed in response to pressure fluctuations in the non-pressure chamber 17. This elastic deformation improves the flow of the viscous fluid between the non-pressure chamber 17 and the pressure chamber 15 and contributes to the performance improvement of the shock absorber 1. In addition, the bellows 7 has its surroundings made atmospheric by the air chamber 69, and the effect is further promoted.

  The end portion 63 of the outer cylinder portion 57 is fixed to the inner peripheral surface 61 of the large diameter portion 21 on the cylinder 3 side by an attachment member 71. That is, the end portion 63 of the outer cylinder portion 57 is bulged and formed on the inner peripheral side. The mounting member 71 is formed in a substantially cylindrical shape, and is fitted into and fixed to the step portion 24 in the cylinder 3. An inner peripheral side of the mounting member 71 is a hole 75 through which the piston rod 13 is inserted and the space 73 between the inner and outer cylinder portions 57 and 59 and the non-pressure chamber 17 are communicated.

  An annular groove 77 is formed on the outer periphery of the mounting member 71 in correspondence with the end 63 of the outer cylinder 57. The end 63 of the outer cylinder 57 is engaged with the annular groove 77, and the end 63 of the outer cylinder 57 is closely fixed to the inner peripheral surface 61 of the large diameter portion 21.

  A fitting portion 79 that fits into the annular wall portion 41 of the piston 5 is provided at the end portion 67 of the inner cylinder portion 59. The tip of the piston rod 13 is inserted through the inner peripheral side of the fitting portion 79. Therefore, the end portion 67 is nipped and fixed between the inner end portion 39 of the piston rod 13 and the annular wall portion 41 of the piston 5 while the fitting portion 79 is fitted in the annular wall portion 41 of the piston 5. Yes. A contact surface 83 that contacts the stepped portion 47 of the piston rod 13 is formed on the inner periphery of the end portion 67 to prevent the fitting portion 79 from coming off.

  The coil spring 9 is disposed between the piston 5 and the closed end of the cylinder 3. One side of the coil spring 9 is in contact with the inner end face 26 of the cylinder 3 by inserting the spring seat 28 of the cylinder 3. The other side of the coil spring 9 is in contact with the spring receiver 29 of the piston 5. Accordingly, the coil spring 9 biases the piston 5 toward the non-pressure chamber 17 with respect to the closed end of the cylinder 3.

As shown in FIGS. 1, 5, and 6, both sides of the coil spring 9 are locked to the cylinder 3 side and the piston 5 side so as not to rotate around the axis. That is, on both sides of the coil spring 9, engagement pieces 85 and 87 made of a spring end are projected. The engaging pieces 85 and 87 are bent inward along the coil shape engaging direction of the coil spring 9 and are parallel to each other. Corresponding to the engaging pieces 85 and 87, the engaging grooves 89 and 91 for engaging the engaging pieces 85 and 87 of the coil spring 9 with the tip 31 of the guide bar 27 and the spring seat 28 of the piston 5 are provided. Are formed respectively. The engagement grooves 89 and 91 are formed by cutting out portions passing through the center so as to divide the cross section of the distal end portion 31 of the guide bar 27 and the spring seat 28 into two. The engaging grooves 89 and 91 are formed from the distal end portion 31 of the guide bar 27 and the proximal end of the spring seat 28 to the distal end in the axial direction.
[Action of shock absorber]
When the shock absorber 1 of the present embodiment receives an external force in the direction of pushing into the cylinder 3 by the control object at the outer end 93 of the piston rod 13, the piston 5 moves in the pressure chamber 15 in conjunction with the operation of the piston rod 13. Move to the side. In response to this movement, the valve element 33 receives the pressure of the viscous fluid and moves to the non-pressure chamber 17 side, and each flow path 25 is closed. At this time, between the valve body 33 and the piston 5, each flow path 25 and the pressure chamber 15 communicate with each other through a gap d formed by the spacer 35, thereby forming an orifice 34. And a viscous fluid moves to the non-pressure chamber 17 side through the orifice 34, and can exhibit a predetermined damper effect.

  When the external force in the pushing direction is released, the piston 5 moves to the non-pressure chamber 17 side by the biasing force of the coil spring 9. In response to this movement, the valve element 33 of the piston 5 receives the pressure of the viscous fluid and moves to the pressure chamber 15 side, and each flow path 25 is opened. Therefore, the viscous fluid can be smoothly moved to the pressure chamber 15 side.

  When the piston 5 moves, the bellows 7 has the outer cylinder portion 57 on one side fixed to the cylinder 3 side and the inner cylinder portion 59 on the other side fixed to the piston 5 side. The inner cylinder part 59 moves with the 5 side. Thus, the bellows 7 contributes to the performance improvement of the shock absorber 1 as described above while being deformed in accordance with the movement of the piston 5.

  When the piston 5 moves, the rotational force around the axis may be input to the piston 5 due to the pressure of the viscous fluid. When the piston 5 tries to rotate about the axis with respect to the cylinder 3 by this rotational force, both sides of the coil spring 9 are locked to the cylinder 3 side and the piston 5 side, so that the piston 5 The rotational force on the 5th side is input and the axial rotation as a whole is restricted by the locking on one side. For this reason, the coil spring 9 can give a rotational resistance force to the piston 5 side by its elastic force, and can restrict the rotation of the piston 5 side to the cylinder 3 side. Therefore, in the shock absorber 1, it is possible to reliably suppress the bellows 7 from being twisted between the cylinder 3 side and the piston 5 side, and it is possible to suppress damage and malfunction of the bellows 7.

Even when a rotational force around the axis is applied to the piston rod 13 outside the cylinder 3 or when the cylinder 3 itself receives a rotational force from the outside, the second rod portion 45 and the first rod of the piston rod 13 Rotational force can be absorbed by relative rotation between the portion 43. Therefore, in the shock absorber 1, it is possible to reliably suppress the rotational force from being transmitted into the cylinder 3, and more reliably suppress the bellows 7 from being twisted between the cylinder 3 side and the piston 5 side. be able to.
[Effect of Example]
In this embodiment, the piston 5 is provided with a flow path 25 that allows the pressure chamber 15 and the non-pressure chamber 17 to communicate with each other. The body 33 is disposed on the pressure chamber 15 side. A spacer 35 is disposed between the piston 5 and the valve body 33 to form a gap d between the pressure chamber 15 and the flow path 25 when the flow path 25 is closed. In the closed state of the valve body 33, the flow path 25 partially closed by the spacer 35 communicates with the pressure chamber 15 through the gap d, thereby forming an orifice 34 and obtaining a predetermined damper effect. It is supposed to be. For this reason, the orifice 34 can be easily formed without processing the piston 5 side.

  In addition, the opening area and flow rate of the orifice 34 can be easily adjusted by changing the plate thickness and diameter, which are the shapes of the spacers 35, and the damper effect can be easily adjusted. In particular, since the orifice 34 can be adjusted and set when the shock absorber 1 is assembled, the degree of freedom of the shock absorber 1 can be improved.

  Further, since the orifice 34 is not processed on the piston 5 side, the versatility of the piston 5 can be improved and the cost can be reduced. Further, when machining the orifice on the piston side, if the orifice is small, it is difficult to form the machining. In the present embodiment, it is only necessary to manage the shape of the spacer 35. Even when the orifice 34 is small, the formation is possible. Is extremely easy.

  A second embodiment of the present invention will be described below with reference to FIG. FIG. 7 is an enlarged cross-sectional view of the piston. Note that the basic configuration of the present embodiment is the same as that of the first embodiment, and the corresponding components will be described with the same reference numerals or the same reference numerals appended with A.

  As shown in FIG. 7, in this embodiment, the spacer 35 of the first embodiment is omitted, and the orifice 34A is formed by the valve body 33A.

  That is, the outer periphery of the valve body 33A is disposed on the inner side of the edge of the flow path 25A disposed on the radially outer side of the piston 5A. Thereby, a part of the flow path 25A is opened at the closed position of the flow path 25A, and the orifice 34A can be formed between the opening of the flow path 25A and the pressure chamber 15.

Therefore, in this embodiment, the orifice 34A can be easily formed without processing the piston 5A side, and the opening area and flow rate of the orifice 34A can be easily changed by changing the diameter of the valve body 33A. It can be adjusted, and the same effect as the above embodiment can be obtained.
[Modification]
FIG. 8 is an enlarged cross-sectional view of a piston according to a modification of the second embodiment, and FIG. The basic configuration of the present modification is the same as that of the second embodiment, and the corresponding components will be described with the same reference numerals or A replaced with B.

  As shown in FIGS. 8 and 9, in this modification, the end portion 26B of the flow path 25B is a long hole. That is, the end portion 26B of the flow path 25B has a long hole shape extending outward in the radial direction of the piston 5B, and the edge portion disposed on the radially outer side is disposed on the radially outer side than the outer periphery of the valve element 33A. ing. Thereby, a part of the elongated hole-shaped opening of the flow path 25B is opened, and the orifice 34B can be formed between the opening of the flow path 25B and the pressure chamber 15.

  Therefore, this modification can also achieve the same effects as those of the second embodiment. In addition, in this modification, the flow rate of the orifice 34B can be easily adjusted by changing the shape of the long hole at the opening 26B of the flow path 25B. In this case, although the piston side is processed, the processing is easier than when the orifice is directly processed and formed, and the orifice 34B can be easily formed and adjusted.

(Example 1) which is sectional drawing of a shock absorber. (Example 1) which is an expanded sectional view of the piston shown in FIG. (Example 1) which is the front view of the piston in the III-III arrow line of FIG. (Example 1) which is an expanded sectional view which shows the connection part of the piston rod shown in FIG. (Example 1) which is sectional drawing in the VV arrow of FIG. (Example 1) which is sectional drawing in the VI-VI line arrow of FIG. (Example 2) which is an expanded sectional view of a piston. It is an expanded sectional view of a piston (modification). It is a top view showing the relationship between the flow path of the piston of FIG. 8, and a valve body (modification).

Explanation of symbols

1 Shock absorber 3 Cylinder 5 Piston 7 Bellows 9 Coil spring (elastic member)
DESCRIPTION OF SYMBOLS 11 Fluid chamber 13 Piston rod 15 Pressure chamber 17 Non-pressure chamber 25 Flow path 33 Valve body 35 Spacer 43 First rod part 45 Second rod part 49 Connection recessed part 51 Connection convex part 85, 87 Engagement piece 89, 91 Engagement groove

Claims (5)

A cylinder having a fluid chamber therein;
A piston that is movably disposed in the fluid chamber of the cylinder and divides the fluid chamber into a pressure chamber side and a non-pressure chamber side;
In the shock absorber provided with the flow path provided in the piston and communicating the pressure chamber side and the non-pressure chamber side,
Provided on the pressure chamber side, provided with a valve body that opens and closes the flow path close to and away from the piston according to the movement of the piston;
A shock absorber provided between the piston and the valve body and provided with a spacer that forms an orifice between the pressure chamber and the flow path when the flow path is closed. The shock absorber according to claim 1,
The shock absorber is characterized in that an opening area of the orifice can be adjusted by changing a plate thickness or a diameter. A cylinder having a fluid chamber therein;
A piston that is movably disposed in the fluid chamber of the cylinder and divides the fluid chamber into a pressure chamber side and a non-pressure chamber side;
In the shock absorber provided with the flow path provided in the piston and communicating the pressure chamber side and the non-pressure chamber side,
Provided on the pressure chamber side, provided with a valve body that opens and closes the flow path close to and away from the piston according to the movement of the piston;
A shock absorber, wherein an orifice is formed between an outer periphery of the valve body and an opening of the flow path at a closed position of the valve body. The shock absorber according to claim 3, wherein
The flow path has an elongated hole-like opening extending in the radial direction of the valve body,
The shock absorber is characterized in that the orifice is formed between an outer periphery of the valve body and an elongated hole-like opening. The shock absorber according to claim 3 or 4,
The said valve body can adjust the opening area of the said orifice by changing a diameter, The shock absorber characterized by the above-mentioned.

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