JP2009024817A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regulate rotation around an axis of a piston side to a cylinder side, preventing the cost from increasing and the assembling work efficiency from decreasing. <P>SOLUTION: A shock absorber 1 comprises a cylinder 3 having a fluid chamber 11 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, a bellows 7 which has one end fixed to the cylinder 3 side and the other end fixed to the piston 5 side to partition the fluid chamber 11 and is deformable according to the movement of the piston 5, and an elastic member 9 disposed in the pressure chamber 15 of the fluid chamber 11 to energize the piston 5 toward the non-pressure chamber 17. Both sides of the elastic member 9 are engaged with the cylinder 3 side and the piston 5 side respectively so that rotation around the axis of the piston 5 side to the cylinder 3 side can be regulated by an elastic force of the elastic member 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shock absorber.

  As a conventional shock absorber, for example, there is one in which a fluid chamber is formed in a cylinder by an elastically deformable bellows.

  As shown in FIG. 7, the shock absorber 101 includes a cylindrical cylinder 105 whose open end is closed by a cylinder cap 103. The cylinder 105 includes a fluid chamber 107 in which a viscous fluid such as silicon oil is sealed. In the fluid chamber 107, a piston 109 is movably disposed, and is divided into a pressure chamber 111 and a non-pressure chamber 113. An insertion hole 110 through which the pressure chamber 111 and the non-pressure chamber 113 are inserted is provided on the piston 109 side. A piston rod 115 extends from the piston 109, and the piston rod 115 is drawn to the outside through the insertion hole 117 of the cylinder cap 103.

  A contractible bellows 119 is provided between the piston rod 115 and the cylinder 105. The bellows 119 has one side fixed to the piston rod 115 and the other side fixed to the cylinder 105 to define a fluid chamber 107.

  In the shock absorber 101, the bellows 119 is elastically deformed in accordance with the pressure fluctuation in the non-pressure chamber 113 in the fluid chamber 107, thereby improving the performance.

  However, in the above structure, when the piston 109 is moved, the piston 109 rotates around the axis, and the bellows 119 may be twisted between the piston 109 side and the cylinder 105 side.

  On the other hand, there is a type in which a so-called D-cut is applied to the cross section of the piston rod and the insertion hole of the lid is made into a corresponding cross sectional shape to restrict the rotation of the piston rod.

  However, in such a configuration, the surface processing of the piston rod becomes complicated and the cost is high. Moreover, when inserting a piston rod in the insertion hole of a cover body, it was necessary to match a cross section, and work efficiency fell.

JP 2001-20988 A

  The problem to be solved is that if the rotation on the piston side is restricted, the cost increases and the assembly work efficiency decreases.

  In the present invention, in order to be able to regulate the rotation on the piston side without reducing cost and working efficiency, both sides of the elastic member arranged in the pressure chamber of the fluid chamber and biasing the piston toward the non-pressure chamber side are provided. The main feature is that the cylinder side and the piston side are respectively locked, and the rotation of the piston side around the axis with respect to the cylinder side is restricted by the elastic force of the elastic member.

  The shock absorber according to the present invention is disposed in the pressure chamber of the fluid chamber and engages both sides of the elastic member for urging the piston toward the non-pressure chamber side with the cylinder side and the piston side, respectively, and the elastic force of the elastic member The rotation around the axis of the piston side relative to the cylinder side can be restricted.

  Therefore, the elastic member that urges the piston toward the non-pressure chamber can be used as a rotation restricting member on the piston side. For this reason, rotation around the axis of the piston side relative to the cylinder side can be regulated easily and reliably while preventing an increase in cost and a reduction in assembly work efficiency.

  The purpose of restricting the rotation of the piston side around the axis with respect to the cylinder side while preventing high cost and reduction in assembly work efficiency is to provide an elastic member for biasing the piston toward the non-pressure chamber side between the piston side and the cylinder side. Realized by locking to.

  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 the 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 1VI-VI line arrow.

[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, the piston 5 is movably disposed via the piston rod 13, and is divided 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, both sides of the coil spring 9 are locked to the cylinder 3 side and the piston 5 side, respectively, and the rotation of the piston 5 side around the axis with respect to the cylinder 3 side is restricted by the elastic force of the coil spring 9. It is like that.

  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 25, the opening amount of the flow path 25 is adjusted by changing the diameter of the spacer 35, and the flow rate of the orifice 34 is adjusted. be able to. The flow rate can also be adjusted by changing the diameter of the flow path 25 on the piston 5 side without changing the shape 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 attachment 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, 87, engaging grooves 89, 91 for engaging the engaging pieces 85, 87 of the coil spring 9 with the tip 31 of the guide bar 27 of the piston 5 and the spring seat 28. Are formed respectively. The engagement grooves 89 and 91 are formed by cutting out a portion passing through the center so as to divide the cross section of the tip 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 portion 93 of the piston rod 13, the piston 5 moves to 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 inputted and the rotation around the axis as a whole is restricted by the locking on one side. At this time, the coil spring 9 can apply 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, both sides of a coil spring 9 disposed in the pressure chamber 15 of the fluid chamber 11 and biasing the piston 5 toward the non-pressure chamber 17 are locked to the cylinder 3 side and the piston 5 side, respectively. The elastic force of the spring 9 can regulate the rotation around the axis of the piston 5 relative to the cylinder 3 side.

  Therefore, in the shock absorber 1, the coil spring 9 can be used as a rotation restricting member on the piston 5 side. For this reason, twisting of the bellows can be easily and reliably regulated without rotation of the piston rod 13 while controlling the rotation of the piston 5 around the cylinder 3 with respect to the cylinder 3 side while preventing the cost and the assembly work efficiency from being lowered. Can be suppressed.

  The coil spring 9 is locked by engaging engagement pieces 85 and 87 projecting on both sides of the coil spring 9 with engagement grooves 89 and 91 provided on the cylinder 3 side and the piston 5 side. Yes. Therefore, the both sides of the coil spring 9 can be locked with a simple structure, and the assembling work can be easily performed.

  In this embodiment, the engaging grooves 89 and 91 are formed from the distal end portion 31 of the guide bar 27 and the proximal end to the distal end of the spring seat 28 in the axial direction. Can be performed easily and reliably.

  Since the locking pieces 85 and 87 are made of spring ends bent along the radial direction of the coil shape of the coil spring 9, the structure can be simplified and can be easily formed.

  The piston rod 13 includes a first rod portion 43 and a second rod portion 45 that are divided in the axial direction in the cylinder 3 and are connected to each other so as to be relatively rotatable about the axis. For this reason, in the shock absorber 1, even when a rotational force around the axis is applied to the piston rod 13 outside the cylinder 3, or even when a rotational force is applied to the cylinder 3 itself from the outside, the rotational force is applied to the cylinder. 3 can be reliably suppressed from being transmitted to the inside. Therefore, the shock absorber 1 can more reliably suppress the twist of the bellows 7.

  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, and a valve that opens and closes the flow path 25 by moving toward and away from the piston 5 as the piston 5 moves. 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.

  Moreover, the 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. In addition, when the orifice 34 is processed on the piston side, if the orifice 34 is small, it is difficult to form the process. On the other hand, in this embodiment, it is only necessary to manage the shape of the spacer 35. Its formation is extremely easy.

  As mentioned above, although the Example of this invention was described, this invention is not limited to this, The various change accompanying the element of a structure is possible. For example, in the present embodiment, the locking pieces 85 and 87 are projected along the radial direction of the coil shape, but may be projected along the axial direction. Further, the locking piece may be omitted, and the engaging groove may be a groove that can accommodate the first winding of the coil spring.

(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. It is sectional drawing of a shock absorber (conventional example).

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;
A bellows having one side fixed to the cylinder side and the other side fixed to the piston side to define the fluid chamber and deformable in accordance with movement of the piston;
A shock absorber provided with an elastic member disposed in the pressure chamber of the fluid chamber and biasing the piston toward the non-pressure chamber;
A shock absorber characterized in that both sides of the elastic member are engaged with the cylinder side and the piston side, respectively, and the rotation of the piston side around the axis with respect to the cylinder side is restricted by the elastic force of the elastic member. The shock absorber according to claim 1,
Engaging pieces projecting on both sides of the elastic member;
A shock absorber provided with an engaging groove for engaging the engaging piece provided on the cylinder side and the piston side corresponding to the engaging piece. The shock absorber according to claim 2,
The elastic member is a coil spring;
The shock absorber according to claim 1, wherein the engagement piece includes a spring end bent along a radial direction of a coil shape of the coil spring. The shock absorber according to any one of claims 1 to 3,
A piston rod extending from the piston to the outside of the cylinder;
The shock absorber according to claim 1, wherein the piston rod is divided in the axial direction and is connected to be rotatable around the axis. The shock absorber according to any one of claims 1 to 4,
The piston includes a flow path communicating the pressure chamber and the non-pressure chamber,
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 spacer disposed between the piston and the valve body, and provided with a spacer that forms a gap between the pressure chamber and the flow path when the flow path is closed;
A shock absorber, wherein an orifice capable of adjusting a flow rate is formed by changing a shape of the spacer.

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