JP6095445B2 - Shock absorber and manufacturing method thereof - Google Patents

Description

  The present invention relates to a shock absorber and a method for manufacturing the same.

  A double cylinder type hydraulic shock absorber is known as a shock absorber incorporated in a vehicle suspension device. Since the cylinder length of the double cylinder type hydraulic shock absorber is shorter than the axis length of the outer tube (outer cylinder), a rod guide is inserted on the inner circumference of the cylinder and fitted on the outer tube on the other side. It is difficult to fit into the cylinder. In particular, a damping force adjustment type hydraulic shock absorber with a control valve is known. Such a shock absorber has a manufacturing problem that it is difficult to fit the rod guide into the cylinder while aligning the cylinder with respect to the outer tube (outer cylinder). In particular, in a shock absorber having a baffle plate, the reaction force of the baffle plate acts between the outer tube and the cylinder. Therefore, when assembling the rod guide, the tip of the rod guide is inserted into the cylinder, and the piston The rod guide is fitted to the outer tube while the cylinder is aligned with the outer tube by operating the rod.

  However, in order for the tip of the rod guide to be inserted into the cylinder prior to the outer tube during assembly, it is necessary to ensure the entire length of the rod guide to a certain level or more, and the degree of freedom in designing the rod guide is reduced. It will be constrained. Moreover, since the fitting length with respect to the cylinder of the front-end | tip part of a rod guide becomes long, durability of the rod guide with respect to the lateral force input into a piston rod falls. In order to compensate for this, it is necessary to increase the strength of the rod guide, which causes an increase in cost.

JP 2012-72857 A

  Therefore, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a shock absorber capable of achieving both improvement in assembly of the rod guide and ensuring durability, and a method for manufacturing the shock absorber. It was made as.

In order to solve the above-described problem, a shock absorber according to the present invention is a shock absorber attached between two members that are relatively movable, a cylinder in which a working fluid is sealed, a piston that is inserted into the cylinder, A piston rod connected to the piston and extending to the outside of the cylinder; an outer cylinder provided on an outer periphery of the cylinder; and a rod guide mounted on the cylinder and the outer cylinder and guiding the piston rod. The rod guide is positioned on the distal end side of the rod guide and is fitted to the inner circumference of the end of the cylinder, and the large diameter is fitted to the inner circumference of the end of the outer cylinder. And a middle diameter portion positioned between the small diameter portion and the large diameter portion, and the shock absorber has one end fitted to the outer periphery of the medium diameter portion of the rod guide and the other end Fitted to the outer periphery of the end of the cylinder. Have a circular sleeve, overlapping length between the said sleeve cylinder is characterized by longer than a length to the end position of the outer cylinder from the end position of the tip end of the large diameter portion of the rod guide .

  In order to solve the above problems, a shock absorber manufacturing method according to the present invention includes a cylinder in which a working fluid is sealed, a piston inserted into the cylinder, and a piston connected to the piston and extending to the outside of the cylinder. And a rod guide that is mounted on the cylinder and the outer cylinder and guides the piston rod, the rod guide comprising: A small-diameter portion that is located on the distal end side of the rod guide and is fitted to the inner periphery of the end portion of the cylinder, a large-diameter portion that is fitted to the inner periphery of the end portion of the outer cylinder, and the small-diameter portion A middle diameter portion positioned between the portion and the large diameter portion, a step of fitting one end of an annular sleeve to the outer periphery of the middle diameter portion of the rod guide, and the other end of the sleeve to the cylinder Engage with end of And fitting the large diameter portion of the rod guide to the inner periphery of the end portion of the outer cylinder while fitting the small diameter portion of the rod guide to the inner periphery of the end portion of the cylinder. It is characterized by having.

  According to the present invention, it is possible to achieve both improvement in assembling property of the rod guide and securing of durability.

It is sectional drawing by the axial plane of the buffer of this embodiment. It is an enlarged view of the principal part in FIG. It is explanatory drawing of the buffer of this embodiment, Comprising: It is a figure which shows the state of the principal part before the open end of an outer cylinder is crimped in the state which the rod guide was fitted to the edge part of a cylinder and an outer cylinder. . It is sectional drawing by the axial plane of the sleeve used for the shock absorber of this embodiment. It is a figure which shows other embodiment of a sleeve. It is explanatory drawing of the manufacturing method of this embodiment, Comprising: It is a figure which shows the state before the upper end part of a cylinder and the lower end part of a sleeve are engaged. It is explanatory drawing of the manufacturing method of this embodiment, Comprising: It is a figure which shows the state at the time of the alignment with which the upper end part of the cylinder and the lower end part of the sleeve were engaged.

  An embodiment of the present invention will be described with reference to the accompanying drawings. First, the shock absorber 1 of the present embodiment will be described with reference to FIG. For convenience of explanation, the vertical direction in FIG. 1 is defined as the vertical direction of the shock absorber 1.

  The shock absorber 1 is a damping force adjusting hydraulic shock absorber provided with a damping force generating mechanism 25 described later. The shock absorber 1 has a multi-cylinder structure in which an outer cylinder 3 is provided on the outer periphery of the cylinder 2, and an annular reservoir 4 is formed between the cylinder 2 and the outer cylinder 3. A piston 5 is slidably fitted in the cylinder 2, and the piston 5 divides the inside of the cylinder 2 into two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B. One end of a piston rod 6 is connected to the piston 5 by a nut 7. The other end side of the piston rod 6 passes through the cylinder upper chamber 2 </ b> A, is inserted into the rod guide 8 and the oil seal 9 mounted on the upper ends of the cylinder 2 and the outer cylinder 3, and extends to the outside of the cylinder 2. A base valve 10 that separates the cylinder lower chamber 2 </ b> B and the reservoir 4 is provided at the lower end of the cylinder 2.

  The piston 5 is provided with passages 11 and 12 through which the cylinder upper chamber 2A and the cylinder lower chamber 2B communicate. The passage 12 is provided with a check valve 13 that allows only fluid to flow from the cylinder lower chamber 2B side to the cylinder upper chamber 2A side. A disk valve 14 is opened in the passage 11 when the pressure of the fluid on the cylinder upper chamber 2A side reaches a certain pressure, and the fluid (pressure) on the cylinder upper chamber 2A side is relieved to the cylinder lower chamber 2B side. Is provided.

  On the other hand, the base valve 10 is provided with passages 15 and 16 through which the cylinder lower chamber 2B and the reservoir 4 communicate. The passage 15 is provided with a check valve 17 that allows only fluid to flow from the reservoir 4 side to the cylinder lower chamber 2B side. The passage 16 is provided with a disk valve 18 which is opened when the pressure of the fluid on the cylinder lower chamber 2B side reaches a certain pressure, and the fluid (pressure) on the cylinder lower chamber 2B side is relieved to the reservoir 4 side. It is done. The cylinder 2 is filled with an oil liquid as a working fluid, and the reservoir 4 is filled with an oil liquid and a gas.

  A separator tube 20 is attached to the outer periphery of the cylinder 2. The separator tube 20 is fitted to the outer periphery of the cylinder 2 via a seal ring 19 whose upper and lower ends are mounted in seal ring grooves. An annular passage 21 communicating with the cylinder upper chamber 2A is formed between the cylinder 2 and the separator tube 20 by a passage 22 provided on the side wall of the upper end portion of the cylinder 2. A small-diameter branch pipe 34 having a connection port 23, which is a passage communicating with the annular passage 21, protrudes from the lower side wall of the separator tube 20. A large-diameter inlet 24 is opened on the side wall of the outer cylinder 3 substantially coaxially with the branch pipe 34, and a damping force generating mechanism 25 is attached to the inlet 24 on the side wall of the outer cylinder 3.

  The damping force generation mechanism 25 has a cylindrical case 26 attached to the inlet 24 of the outer cylinder 3. In the case 26, a pilot type (back pressure type) main valve 27 and a pilot valve 28 which is a solenoid-driven pressure control valve for controlling the valve opening pressure of the main valve 27 are provided, and further downstream of the pilot valve 28. On the side, a fail valve 29 is provided which operates at the time of failure. A connecting pipe 30 that forms an inlet passage is liquid-tightly inserted into the connection port 23 of the branch pipe 34. Then, the oil liquid is introduced from the connection port 23 to the connecting pipe 30, passes through the main valve 27, the pilot valve 28, and the fail valve 29 and is circulated to the chamber 26 </ b> A surrounded by the case 26. The oil in the chamber 26 </ b> A flows into the reservoir 4 through the passage 31 at the end of the case 26 and the inlet 24 of the outer cylinder 3.

  At this time, before the main valve 27 is opened, a damping force is generated by controlling the flow of the oil liquid by the pilot valve 28. When the main valve 27 is opened, the damping force mainly by the main valve 27 is mainly generated. Occur. A part of the oil fluid upstream of the pilot valve 28 is introduced into the back pressure chamber 32 at the back of the main valve 27, and the internal pressure acts in the valve closing direction of the main valve 27. The damping force is adjusted by adjusting the control pressure of the pilot valve 28, and the control pressure of the pilot valve 28 is adjusted by a control current supplied to the solenoid 35 via the lead wire 36. Thereby, the internal pressure of the back pressure chamber 32 changes, and the valve opening pressure and the opening degree of the main valve 27 are adjusted.

  The fail valve 29 is closed when the vehicle is stopped waiting for a signal, or when the solenoid 35 is de-energized, and the flow of the oil is allowed to flow in place of the normally open pilot valve 27. By limiting, it functions to prevent an excessive decrease in the damping force and maintain an appropriate damping force. Further, a baffle plate 33 is provided in the reservoir 4 at a position corresponding to the inlet 24 of the outer cylinder 3 on the outer peripheral surface of the separator tube 20, and the baffle plate 33 is connected to the passage 31 and the outer side from the damping force generation mechanism 25. The flow of the oil liquid that passes through the inlet 24 of the cylinder 3 and flows into the reservoir 4 is regulated. Thereby, generation | occurrence | production of the vortex and bubble near the liquid surface by the jet flow of the oil which flows in into the reservoir | reserver 4 through the inflow port 24 is prevented, and it suppresses that the gas in the reservoir | reserver 4 melt | dissolves in the oil. As a result, generation of aeration and cavitation can be suppressed and a stable damping force can be obtained.

  Next, the fitting structure of the rod guide 8 will be described. As shown in FIG. 2, the rod guide 8 is formed in a substantially cylindrical shape having a central axis CL. The rod guide 8 includes a small diameter portion 41 located on the distal end side (lower side in FIG. 2) of the rod guide 8, a large diameter portion 42 located on the proximal end side (upper side in FIG. 2) of the rod guide 8, and a small diameter portion. And a medium-diameter portion 43 that is located between the large-diameter portion 42 and has an outer diameter (diameter) larger than the outer diameter of the small-diameter portion 41 and smaller than the outer diameter of the large-diameter portion 42. In other words, the rod guide 8 is formed with a large diameter portion 42, a medium diameter portion 43, and a small diameter portion 41 in order from the top in FIG.

  A cylindrical sleeve 44 is attached to the rod guide 8. In the sleeve 44, the inner periphery of the upper end portion 45 (one end) is fitted to the outer periphery of the intermediate portion 43 of the rod guide 8. Further, the sleeve 44 has an end face of the upper end portion 45 abutted against an annular step portion 46 formed between the large diameter portion 42 and the medium diameter portion 43 of the rod guide 8, so And is positioned in the central axis CL direction (vertical direction in FIG. 2). Further, the lower portion in FIG. 2 than the portion fitted to the intermediate portion 43 of the rod guide 8 in the inner circumference of the sleeve 44 is fitted to the outer circumference of the end portion of the cylinder 2. The outer periphery of the small diameter portion 41 of the rod guide 8 is fitted to the inner periphery of the end portion of the cylinder 2.

  The rod guide 8 is positioned in the direction of the central axis CL with respect to the cylinder 2 by abutting the end surface of the cylinder 2 against an annular step 47 formed between the small diameter portion 41 and the medium diameter portion 43. . As shown in FIG. 3, the overlapping length L1 of the sleeve 44 and the cylinder 2 in the direction of the central axis CL, in other words, the fitting length L1 of the sleeve 44 and the cylinder 2 is large. It is set longer than the length L2 from the end position P1 on the distal end side (lower side in FIG. 3) of the diameter portion 42 to the opening side end position P2 of the outer cylinder 3 before the end portion is caulked.

  Thereby, when the rod guide 8 is assembled, the lower end portion 48 (the other end) of the sleeve 44 is moved before the large diameter portion 42 of the rod guide 8 is engaged (inserted) with the inner periphery of the end portion of the outer cylinder 3. It is engaged with the end of the cylinder 2. In other words, the end position P1 of the large-diameter portion 42 of the rod guide 8 coincides with the end position P2 of the outer cylinder 3 when the rod guide 8 to which the sleeve 44 is attached is fitted to the ends of the cylinder 2 and the outer cylinder 3. Prior to this, the end of the cylinder 2 is inserted into the inner periphery of the lower end 48 of the sleeve 44.

  In addition, as shown in FIG. 4, a chamfered shape having a chamfer dimension larger than the chamfered portion 49 of the inner peripheral side corner of the upper end 45 at the inner peripheral side corner of the lower end portion 48 of the sleeve 44, in other words, The guide portion 50 having a tapered shape is formed, and the above-described “the lower end portion 48 of the sleeve 44 is engaged with the end portion of the cylinder 2” means that the end portion of the cylinder 2 is at least the guide portion 50 of the sleeve 44. The state that passed through. In addition to being formed in a chamfered shape as shown in FIG. 4, the guide portion 50 is formed by expanding the tip of the lower end portion 48 of the sleeve 44 in a tapered shape as shown in FIG. be able to. Further, reference numeral 51 in FIGS. 2 and 3 denotes a bush whose outer periphery is fitted to the inner periphery of the rod guide 8 and whose inner periphery is slidably contacted with the outer periphery of the piston rod 6.

Next, a method for manufacturing the shock absorber 1 will be described. Here, only the process of fitting the rod guide 8 to the ends of the cylinder 2 and the outer cylinder 3 will be described, and the description of the same processes as other known manufacturing methods will be omitted.
FIG. 6 shows a state before the rod guide 8 is fitted to the ends of the cylinder 2 and the outer cylinder 3. In this state, the lower end 48 (the other end) of the sleeve 44 is not in contact with the cylinder 2 (not engaged). The inner periphery of the upper end portion 45 (one end) of the sleeve 44 is fitted in advance on the outer periphery of the medium diameter portion 43 of the rod guide 8. In addition, a baffle plate 33 is attached in the reservoir 4 before the rod guide 8 shown in FIG. 6 is assembled to the ends of the cylinder 2 and the outer cylinder 3, and a damping force is applied to the outer cylinder 3. A generation mechanism 25 is attached (see FIG. 1).

  In the state shown in FIG. 6, the rod guide 8 to which the sleeve 44 is attached (hereinafter referred to as the rod guide 8) is made to approach the cylinder 2 and the outer cylinder 3 (downward direction in FIG. 6), in other words, the base Move to the valve 10 (see FIG. 1) side. In the course of movement, first, the outer peripheral side corner of the end of the cylinder 2 contacts the guide 50 of the lower end 48 of the sleeve 44. Then, the end portion of the cylinder 2 is guided by the guide portion 50 of the sleeve 44, whereby the end portion of the cylinder 2 is guided into the sleeve 44. As a result, the end of the cylinder 2 and the lower end 48 of the sleeve 44 can be easily engaged.

  FIG. 7 shows a state in which the end of the cylinder 2 and the lower end 48 of the sleeve 44 are engaged. In a state where the end of the cylinder 2 and the lower end 48 of the sleeve 44 are engaged, in other words, in a state where the tip of the end of the cylinder 2 is inserted into the inner periphery of the lower end 48 of the sleeve 44, the rod guide The large diameter portion 42 of 8 is not inserted into the end portion of the outer cylinder 3. Therefore, by operating the piston rod 6 so that the large diameter portion 42 of the rod guide 8 can be inserted (fitted) into the inner periphery of the end portion of the outer cylinder 3 in the state shown in FIG. The cylinder 2 can be aligned with respect to the cylinder 3, that is, the center axis of the cylinder 2 and the center axis of the outer cylinder 3 can be matched.

  Then, in a state where the inner periphery of the lower end portion 48 of the sleeve 44 is engaged with the outer periphery of the end portion of the cylinder 2, that is, in a state where the cylinder 2 is aligned with respect to the outer cylinder 3, the rod guide 8 is moved as shown in FIG. The large diameter portion 43 of the rod guide 8 is fitted to the inner periphery of the end of the outer cylinder 3 while the small diameter portion 41 of the rod guide 8 is fitted to the inner periphery of the end of the cylinder 2. Combine. 3 shows a state in which the rod guide 8 is fitted to the end portions of the cylinder 2 and the outer cylinder 3, that is, the end surface of the cylinder 2 is abutted against the stepped portion 47 of the rod guide 8, and the rod guide 8 has the center axis CL. The state positioned in the direction is shown. In this state, an axial force is generated in the cylinder 2 via the rod guide 8 by caulking the end of the outer cylinder 3.

  According to this embodiment, the rod guide 8 has a small-diameter portion 41 fitted to the inner periphery of the end portion of the cylinder 2, a large-diameter portion 42 fitted to the inner periphery of the end portion of the outer cylinder 3, An intermediate diameter portion 43 positioned between the small diameter portion 41 and the large diameter portion 42 is provided. An upper end portion 45 (one end) of the sleeve 44 is fitted into the intermediate diameter portion 43 of the rod guide 8, and the sleeve 44 and the cylinder 22 overlap length (fitting length) L1 is longer than the length L2 from the end position P1 on the distal end side of the large diameter portion 43 of the rod guide 8 to the opening side end position P2 of the outer cylinder 3. Set long.

  Thereby, when the rod guide 8 is assembled, that is, when the rod guide 8 is fitted to the end portions of the cylinder 2 and the outer cylinder 3, the end portion of the cylinder 2 and the lower end portion 48 of the sleeve 44 are engaged. In other words, the large-diameter portion 42 of the rod guide 8 is inserted into the inner periphery of the end of the outer cylinder 3 with the tip of the end of the cylinder 2 inserted into the inner periphery of the lower end 48 of the sleeve 44. By operating the piston rod 6 so that the cylinder 2 can be operated, the cylinder 2 can be easily aligned with the outer cylinder 3.

Therefore, the assembling property of the rod guide 8 to the cylinder 2 and the outer cylinder 3 can be improved, and the number of assembling steps of the shock absorber 1 can be reduced. As a result, the manufacturing cost of the shock absorber 1 can be reduced. .
Further, in the conventional damping force adjustment type hydraulic shock absorber mounted on the control valve, the tip end portion of the rod guide 8 (corresponding to the small diameter portion 41 of the present embodiment) is inserted into the cylinder 2 before the outer cylinder 3 at the time of assembly. In order to achieve this, it is necessary to secure the entire length of the rod guide 8 to a certain level or more, and the degree of freedom in designing the rod guide 8 is restricted. However, in the shock absorber 1 of the present embodiment, the rod guide 8 The overall length can be shortened compared to the conventional case, and the overall length of the shock absorber 1 can be shortened.
Moreover, since it can implement only by mounting | wearing the rod guide 8 with the sleeve 44, the increase in manufacturing cost can be suppressed, without the structure becoming complicated.
Furthermore, since the freedom degree of design of the rod guide 8 is improved, it is possible to design the rod guide 8 in a shape in consideration of strength, and the durability of the rod guide 8 can be ensured.

1 shock absorber, 2 outer cylinder, 3 cylinder, 5 piston, 6 piston rod, 8 rod guide, 41 small diameter part, 42 large diameter part, 43 medium diameter part, 44 sleeve, 45 upper end part (one end of sleeve), 48 lower end Part (the other end of the sleeve)

Claims (2)

A shock absorber mounted between two relatively movable members,
A cylinder filled with a working fluid;
A piston inserted into the cylinder;
A piston rod connected to the piston and extending to the outside of the cylinder;
An outer cylinder provided on the outer periphery of the cylinder;
A rod guide that is mounted on the cylinder and the outer cylinder and guides the piston rod;
With
The rod guide is
A small-diameter portion that is located on the distal end side of the rod guide and is fitted to the inner periphery of the end portion of the cylinder; a large-diameter portion that is fitted to the inner periphery of the end portion of the outer cylinder; and the small-diameter portion; A medium diameter portion located between the large diameter portion and
The shock absorber is
One end is fitted on the outer periphery of the diameter in said rod guide, have a circular sleeve other end is fitted on the outer periphery of an end portion of said cylinder,
The shock absorber according to claim 1, wherein an overlap length between the sleeve and the cylinder is longer than a length from an end position on a distal end side of the large diameter portion of the rod guide to an end position of the outer cylinder . A cylinder filled with a working fluid;
A piston inserted into the cylinder;
A piston rod connected to the piston and extending to the outside of the cylinder;
An outer cylinder provided on the outer periphery of the cylinder;
A rod guide that is mounted on the cylinder and the outer cylinder and guides the piston rod;
A shock absorber manufacturing method comprising:
A small-diameter portion that is positioned on the rod guide on the tip side of the rod guide and is fitted to the inner periphery of the end portion of the cylinder; and a large-diameter portion that is fitted to the inner periphery of the end portion of the outer cylinder; Providing a medium diameter portion located between the small diameter portion and the large diameter portion,
Fitting one end of an annular sleeve to the outer periphery of the middle diameter portion of the rod guide;
Engaging the other end of the sleeve with the end of the cylinder;
Fitting the large diameter portion of the rod guide to the inner periphery of the end portion of the outer cylinder while fitting the small diameter portion of the rod guide to the inner periphery of the end portion of the cylinder;
A method of manufacturing a shock absorber, comprising:

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