JP5793037B2 - Shock absorber - Google Patents

Description

  The present invention relates to an improvement of a shock absorber.

  The shock absorber is used, for example, in a suspension device of a vehicle such as an automobile, and as disclosed in Patent Document 1, a shock absorber is inserted into the cylinder so as to be movable in the axial direction. A rod.

  Further, the shock absorber includes a rod guide fixed to the cylinder and pivotally supporting the rod, and an annular seal member stacked on the outside air side of the rod guide and fixed to the cylinder.

  The seal member includes an inner peripheral seal that is disposed on the inner peripheral side and is in sliding contact with the outer periphery of the rod. This inner peripheral seal is formed in a bifurcated manner, and consists of a dust seal on the outside air side and an oil seal on the cylinder side.

  The dust seal scrapes off foreign matter adhering to the outer periphery of the rod to prevent foreign matter from entering the cylinder and preventing the oil seal from being damaged by foreign matter. On the other hand, the oil seal scrapes off the working fluid adhering to the outer periphery of the rod and prevents the working fluid in the cylinder from flowing out.

  A lubricant film is formed on the outer periphery of the rod between the seal and the inner peripheral seal of the seal member. Thereby, the sliding surfaces of the rod and the seal member are lubricated, and good slidability of the rod and the seal member is ensured.

JP 2007-120514 A

  However, in the conventional shock absorber, the following problems may be pointed out.

  That is, when an aqueous fluid such as an aqueous glycol solution is selected as the working fluid stored in the cylinder, the aqueous fluid has a lower viscosity and poor lubricity than an oil-based working fluid such as mineral oil.

  Therefore, in order to ensure good lubricity when an aqueous fluid is selected, it is preferable to increase the thickness of the lubricating film. However, in this case, the working fluid that adheres to the outer periphery of the rod and is taken out of the cylinder increases. The working fluid that evaporates when exposed to the outside air may increase and the working fluid may be insufficient in the cylinder.

  Accordingly, an object of the present invention is to provide a shock absorber capable of preventing a shortage of working fluid in a cylinder even when a working fluid having poor lubricity such as an aqueous fluid is selected and the lubricating film is thickened. It is to be.

Means for solving the above problems, a cylinder housing the internal working fluid, the rod and, sliding on the rod periphery provided at one end side of the cylinder to be inserted movably in the axial direction within the cylinder contact and a sealing member for preventing the outflow of the working fluid in the cylinder, the shock absorber lubrication film between the sealing member and the rod is formed, it is laminated on the counter-cylinder side of the sealing member The wiper ring includes a wiper ring that slides on the outer periphery of the rod and thins the lubricating film . The wiper ring includes a wiper that is formed in an annular shape and has a tip that slides on the outer periphery of the rod. than the angle between the surface, it is Rukoto is greater towards the angle between the cylinder side surface and the rod outer circumferential surface of the wiper.

  According to the present invention, by providing the wiper ring, a thick lubricating film is formed between the seal member and the rod to ensure good slidability, and the lubricating film is thinned by the wiper to open air. The amount of the working fluid that is exposed can be reduced.

  Accordingly, it is possible to reduce the evaporation amount of the working fluid and prevent the working fluid from being insufficient in the cylinder.

It is a longitudinal cross-sectional view which shows partially the buffer which concerns on one embodiment of this invention. It is explanatory drawing which expands the principal part of FIG. 1 and shows in principle. It is a longitudinal cross-sectional view which shows the modification of the buffer which concerns on one embodiment of this invention partially. It is a longitudinal cross-sectional view which shows partially the other modification of the buffer which concerns on one embodiment of this invention.

  A shock absorber according to an embodiment of the present invention will be described below with reference to the drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts.

  As shown in FIG. 1, a shock absorber A according to the present embodiment includes a cylinder 1 that contains a working fluid therein, a rod 2 that is movably inserted in the cylinder 1 in the axial direction, and the cylinder 1. 2 is provided on one end side (upper end side in FIG. 1) of the rod 2 and slidably contacts the outer periphery of the rod 2 to prevent the working fluid from flowing out of the cylinder 1, and as shown in FIG. A lubricating film 4 is formed between the member 3 and the rod 2.

  Further, the shock absorber A is provided with a wiper ring 5 that is laminated on the side opposite to the cylinder of the seal member 3 (upper side in FIGS. 1 and 2) and that slides on the outer periphery of the rod 2 to make the lubricating film 4 thinner.

  Although the structure of the shock absorber A is well known and not shown in detail, the shock absorber A is held at the lower end of the rod 2 and is slidably in contact with the inner periphery of the cylinder 1 and a piston (not shown) on the outside of the cylinder 1. And an outer cylinder 6 that forms a reservoir R1 between the cylinder 1 and the cylinder 1 and is configured as a double-cylinder shock absorber that compensates for a change in the cylinder volume corresponding to the volume of the rod that appears and disappears in the cylinder 1 with the reservoir R1. The

  The working fluid stored in the cylinder 1 is an aqueous fluid such as an aqueous glycol solution or water. The cylinder 1 is divided into upper and lower parts in FIG. 1 by the piston, an extension side working chamber R is formed on the rod side (upper side in the figure), and a pressure side action (not shown) on the piston side (lower side in the figure). A chamber is formed. The extension side working chamber R and the pressure side working chamber communicate with each other via a flow path (not shown) formed in the piston.

  A base member (not shown) that partitions the reservoir R1 and the pressure side working chamber is fixed to the bottom portion (lower portion in FIG. 1) of the cylinder 1. The pressure side working chamber and the reservoir R1 communicate with each other via a flow path (not shown) formed in the base member.

  The shock absorber A is a known damping force composed of a laminated leaf valve, an orifice or the like that gives a predetermined flow path resistance when the working fluid passes through the flow path formed in the piston and the flow path formed in the base member. A generating means is provided.

  Accordingly, when the shock absorber A extends and retracts in and out of the cylinder 1, the working fluid passes through each flow path between the expansion side working chamber R and the pressure side working chamber and between the pressure side working chamber and the reservoir R 1. The shock absorber A generates a damping force due to the flow path resistance when the working fluid passes through each flow path.

  Hereinafter, the rod 2 will be slidably supported by an annular rod guide 7 fixed to the opening 1a of the cylinder 1 on the upper side in FIG. The rod guide 7 is disposed from the opening 1a of the cylinder 1 to the inner periphery of the outer cylinder 6 in the upper part 6a in FIG. 1, and closes the upper opening in FIG.

  Further, on the outside air side (upper side in FIG. 1) of the rod guide 7, a seal member 3, a spacer 8, a washer 9, and a wiper ring 5 are sequentially stacked from the cylinder side (lower side in FIG. 1). . The rod guide 7, the seal member 3, the spacer 8, the washer 9, and the wiper ring 5 are clamped and fixed between the upper end 6b and the cylinder 1 by crimping the upper end 6b of the outer cylinder 6 inward. The

  The seal member 3 includes an annular insert metal 30 formed in an annular shape, an annular inner peripheral seal 31 disposed on the inner peripheral side of the insert metal 30, and an annular outer peripheral seal disposed on the outer peripheral side of the insert metal. 32.

  The inner circumferential seal 31 is divided into a top and bottom in FIG. 1 and a dust seal 31a disposed on the outside air side (upper side in FIG. 1) and an oil seal 31b disposed on the cylinder side (lower side in FIG. 1). Become. As shown in FIG. 2, the tips of the dust seal 31 a and the oil seal 31 b are in sliding contact with the outer periphery of the rod 2 through the lubricating film 4.

  The thickness of the lubricating film 4 is set to be thicker than that when the working fluid is made of an oil-based fluid. With this lubricating film 4, the rod 2 can pass through the inner peripheral seal 31 even when the working fluid is an aqueous fluid. It becomes possible to move in the axial direction smoothly.

  Returning, the outer peripheral seal 32 shown in FIG. 1 is in close contact with the inner periphery of the outer cylinder 6, closes the gap between the outer periphery of the rod guide 7 and the inner periphery of the outer cylinder 6, and the gas contained in the reservoir R 1 Prevents the working fluid from leaking to the outside.

  A check seal 33 is provided on the cylinder side surface (the lower surface in FIG. 1) of the insert metal 30. The check seal 33 is formed in the rod guide 7 so as to open and close a passage 70 communicating with the reservoir R1, and the working fluid scraped onto the rod guide 7 by the oil seal 31b moves to the reservoir R1. Is only allowed.

  The spacer 8 stacked immediately above the seal member 3 in FIG. 1 forms a lubrication chamber 40 between its inner periphery and the rod 2. Further, the inner circumference of the spacer 8 on the seal member side (lower side in FIG. 1) is set so as not to interfere with the inner circumference seal 31, and the outside air side (upper side in FIG. 1) inner diameter of the spacer 8 is expanded. Thus, a step 80 is formed at the boundary.

  A holding material 81 is laminated on the step portion 80 of the spacer 8. The holding material 81 is formed in an annular shape and is in sliding contact with the outer periphery of the rod 2. Furthermore, the holding material 81 is made of a material capable of holding a liquid, and holds a lubricating liquid in the present embodiment. Therefore, when the rod 2 passes through the holding material 81, the lubricating liquid is applied to the outer periphery of the rod 2. The lubricating liquid is a fluid having a higher viscosity than the working fluid and is preferably an oil-based fluid such as mineral oil, but may be an aqueous fluid. Further, since the holding member 81 is raised by the spacer 8, it does not interfere with the inner peripheral seal 31.

  Subsequently, the washer 9 stacked immediately above the spacer 8 in FIG. 1 holds the holding member 81 together with the spacer 8. Further, the thickness of the washer 9 is set so that the holding material 81 does not interfere with the wiper ring 5.

  The wiper ring 5 is formed in an annular shape and is fixed to the cylinder 1. The wiper ring 5 is disposed on the inner peripheral side of the insert metal 50 and is inclined toward the cylinder 1 side (lower in FIG. 1). And a wiper 51. As shown in FIG. 2, the tip of the wiper 51 is in sliding contact with the outer periphery of the rod 2, and a portion of the lubricating film 4 formed by the seal member 3 is scraped to reduce the thickness of the lubricating film 4. . In the present embodiment, the angle between the cylinder side surface 51b of the wiper 51 and the outer peripheral surface of the rod 2 is set larger than the angle between the outside air side surface 51a (upper surface in FIG. 2) of the wiper 51 and the outer peripheral surface of the rod 2.

  Next, the operation and effect of the shock absorber A according to the present embodiment will be described. When the rod 2 moves upward in FIG. 2 and retreats from the cylinder 1, excess working fluid adhering to the outer periphery of the rod 2 is oil seal. It is scraped off at 31b.

  At this time, a lubricant film 4 made of a working fluid is formed on the outer periphery of the rod 2, and the thickness of the lubricant film 4 is set to a thickness that allows the rod 2 to smoothly move in the axial direction in the seal member 3. The

  Next, since the rod 2 passes through the holding material 81, the lubricant is applied to the outer periphery of the rod 2. As a result, the fluid constituting the lubricating film 4 is composed of the working fluid and the lubricating liquid, and a part of the lubricating film 4 is scraped off and thinned by the wiper ring 5 that passes next.

  Accordingly, the amount of the working fluid that comes out of the wiper ring 5 in FIG. 1 and is exposed to the outside air is reduced, and the evaporation amount of the working fluid can be reduced to prevent the working fluid from being insufficient in the cylinder 1. It becomes.

  Further, in the present embodiment, since the lubricating liquid is applied to the outer periphery of the rod 2, the viscosity of the fluid constituting the lubricating film 4 is higher than that when the lubricating film 4 is made of only the working fluid, and the thin lubricating film 4 Good slidability of the rod 2 and the wiper ring 5 can be ensured with a thickness of.

  Further, in the present embodiment, since the holding material 81 is disposed between the seal member 3 and the wiper ring 5, the rod 2 enters the cylinder 1 even if the lubricant film 4 is thinned by the wiper ring 5. When working, the working fluid or lubricating liquid held by the holding material 81 can be applied to the outer periphery of the rod 2 before passing through the seal member 3. Therefore, insufficient lubrication between the seal member 3 and the rod 2 does not occur.

  In the present embodiment, since the angle between the cylinder side surface 51b of the wiper 51 and the outer peripheral surface of the rod 2 is set larger than the angle between the outside air side surface 51a of the wiper 51 and the outer peripheral surface of the rod 2, the working fluid It is possible to prevent the lubricant from leaking to the outside of the wiper ring 51.

  In the present embodiment, the spacer 8 has a stepped portion 80, and the holding member 81 is held between the stepped portion 80 and the washer 9. Therefore, the holding member 81 is the seal member 3 and the wiper ring 5. It is possible to prevent the interference. Moreover, by providing the said structure, installation of the holding material 81 is easy and it is possible to manufacture the spacer 8 and the washer 9 easily.

  Although preferred embodiments of the present invention have been described in detail above, it should be understood that modifications, variations and changes may be made without departing from the scope of the claims.

  For example, in the above-described embodiment, the shock absorber A is configured as a double-tube shock absorber. However, the shock absorber A includes a free piston that divides the air chamber at the bottom of the cylinder 1, and a rod is provided in the air chamber. It may be configured as a single-cylinder shock absorber that compensates for changes in the volume of the cylinder in and out.

  In the above embodiment, the lubricant is applied to the outer periphery of the rod 2 with the holding material 81. However, it is not always necessary to provide the holding material 81, and as shown in FIG. It may be housed. In this case, since the holding member 81 does not interfere with the seal member 3 and the wiper ring 5, the spacer 8 can be formed in a cylindrical shape and the washer 9 can be omitted.

  Further, even if the lubricating film 4 is thinned by applying a lubricating liquid to the outer periphery of the rod 2, there is no lack of lubrication between the wiper ring 5 and the rod 2, but it is not always necessary to apply a lubricating liquid to the outer periphery of the rod 2. Absent.

When this lubricant is not applied to the outer periphery of the rod 2, in order to ensure good slidability between the wiper ring 5 and the rod 2 even if the lubricant film 4 is thinned, for example, the tightening force of the wiper 51 is applied to the oil seal 31b. It is preferable to set the wiper 51 to be smaller than the tension force or to form the wiper 51 with a material having good lubricity. Incidentally, this when armed configuration, even to hold the working fluid in the holding member 81, holding member 81 may be used as housing a working fluid to the lubrication chamber 40 without providing.

  In the above embodiment, the angle between the cylinder side surface 51b of the wiper 51 and the outer peripheral surface of the rod 2 is set larger than the angle between the outside air side surface 51a of the wiper 51 and the outer peripheral surface of the rod 2. The angle between the outside air side surface 51a of the wiper 51 and the outer peripheral surface of the rod 2 may be equal to the angle between the cylinder side surface 51b of the wiper 51 and the outer peripheral surface of the rod 2.

  Moreover, in the said embodiment, although the sealing member 3 is provided with the dust seal | sticker 31a, it is good also as not providing the dust seal | sticker 31a in the sealing member 3, but providing a dust seal | sticker in the external air side (upper side in FIG. 1) of the wiper ring 5. .

  Further, in the above embodiment, the step portion 80 is formed in the spacer 8, the holding member 81 is sandwiched between the step portion 80 and the washer 9, and the holding member 81 interferes with the seal member 3 and the wiper ring 5. Is not limited to this. For example, as shown in FIG. 4, an annular groove 82 may be provided in the center of the inner periphery of the spacer 8, and the holding material 31 may be engaged with the groove 82.

A Shock absorber R Extension side working chamber R1 Reservoir 1 Cylinder 2 Rod 3 Seal member 4 Lubricating film 5 Wiper ring 6 Outer cylinder 7 Rod guide 8 Spacer 9 Washer 30, 50 Insert metal 31 Inner peripheral seal 31a Dust seal 31b Oil seal 32 Outer seal 33 Check seal 40 Lubrication chamber 51 Wiper 80 Step portion 81 Holding material 82 Groove

Claims (3)

A cylinder for housing the internal working fluid, movable with the rod to be inserted, the outflow of the working fluid is provided on one end side of the cylinder in sliding contact with the cylinder to the rod outer periphery in the axial direction within the cylinder and a sealing member for preventing, in a shock absorber lubricating film between the sealing member and the rod is formed,
A wiper ring that is laminated on the non-cylinder side of the seal member and is in sliding contact with the outer periphery of the rod to thin the lubricating film ;
The wiper ring includes a wiper formed in an annular shape and having a tip slidably contacting the outer periphery of the rod. The cylinder side surface of the wiper and the outer peripheral surface of the rod are larger than the angle between the outer air side surface of the wiper and the outer peripheral surface of the rod. buffer, wherein Rukoto the direction of the angle is larger settings with. An annular spacer interposed between the wiper ring and the seal member, the lubrication chamber is formed between the spacer and the rod, the working fluid or lubricant to the lubrication chamber is accommodated the shock absorber according to claim 1, wherein the. Is formed in an annular shape on the lubricant chamber in sliding contact holding member is provided on the rod periphery, according to claim 2, characterized in that the working fluid or the lubricating fluid of said lubricating chamber into the holding member is held Shock absorber.

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