JP5570174B2 - Piston for hydraulic shock absorber - Google Patents

Description

  The present invention relates to a piston for a hydraulic shock absorber.

  As described in Patent Document 1, as a piston for a hydraulic shock absorber, a piston body which can be fixed to a piston rod inserted into a cylinder and can be divided into two oil chambers, and one end surface of the piston body A hole-like channel extending from the first to the middle in the axial direction and opened to one oil chamber, and a groove that is turned to the outer periphery of the piston body and communicates with the hole-like channel and opens to the other oil chamber Some of them have a flow path.

  In the above-described piston, a petal-like (or ring-shaped) valve seat surrounding the opening of the hole-shaped flow path is projected on one end surface of the piston body, and a disc valve that contacts and separates from the valve seat is provided.

  When the hydraulic shock absorber expands and contracts, the piston slides in the cylinder together with the piston rod. For example, when the other oil chamber is pressurized, the hydraulic oil pressure in the other oil chamber is removed from the groove-like flow path of the piston body. Flows into the flow path and thus acts on the disc valve. When the pressure acting on the disc valve becomes larger than the spring force of the disc valve, the outer peripheral edge of the disc valve is deflected and separated from the valve seat, and the disc valve is opened. As a result, the hydraulic oil in the other oil chamber flows into one oil chamber, and a damping force is generated due to the throttle resistance between the disk valve and the valve seat during this time, thereby suppressing the expansion and contraction vibration of the hydraulic shock absorber.

63-32992

  FIG. 9A is a schematic diagram showing a piston 1 manufactured by conventional sintering or casting, in which 1A is a piston body, 1B is a valve seat, 1C is an outer peripheral groove, and 1D is a hole-like channel. FIG. 9B shows a process of turning the outer peripheral groove 1C of the piston main body 1A with a turning tool 2 of a lathe to produce a groove-like channel 1E communicating with the hole-like channel 1D.

  In the prior art, the inner surface f1 of the hole-shaped flow path 1D that has been prepared on the piston body 1A by sintering or casting, and the inner surface f1 that communicates with the groove-shaped flow path 1E is concentric with the center c of the piston main body 1A. It is formed by the circular arc surface which makes | forms.

  On the other hand, the cutting tool 2 rotates the groove bottom of the outer peripheral groove 1C in the piston main body 1A that is rotated by being centered on the center c of the piston main body 1A. Therefore, the cutting tool 2 uses the groove bottom of the outer peripheral groove 1C of the piston main body 1A. Cutting is performed with an arc surface concentric with the center c.

  For this reason, when the cutting tool 2 cuts the groove bottom of the outer peripheral groove 1C to form the groove-shaped flow path 1E communicating with the hole-shaped flow path 1D, the cutting edge 2A of the bit 2 has the hole-shaped flow path 1D. The last thin film (thin film) having the same curvature as the inner surface f1 is cut at once over the entire range corresponding to the entire inner surface f1 communicating with the groove-shaped flow channel 1E. And the communication portion P of the groove-like flow path 1E is formed. At this time, due to the rotational deflection of the main spindle of the lathe and the roundness of the piston body 1A, the communicating portion P between the hole-like channel 1D and the groove-like channel 1E is cut so that the thin skin is folded, and some of them are variably formed. It tends to remain. Therefore, a man-hour for removing the burrs B remaining in the communicating portion P between the hole-like channel 1D and the groove-like channel 1E is required, and the productivity of the piston 1 is hindered.

An object of the present invention, a hydraulic shock absorber which a groove-like passage provided on the outer periphery of the piston body by turning, communicating with the hole shaped flow path is a fabricated already in the piston body is extended in the axial direction of its In the piston, it is to suppress the generation of burrs at the communication portion between the groove-like channel and the hole-like channel.

The invention according to claim 1 is a piston main body that can be fixed to a piston rod inserted into the cylinder and can be divided into two oil chambers, and an intermediate portion in the axial direction from one end surface of the piston main body. And the center of the piston main body in which the hole-shaped flow path has been prepared is centered and turned to the outer periphery of the piston main body. In addition, in the hydraulic shock absorber piston having a groove-shaped channel that communicates with the hole-shaped channel and opens to the other oil chamber, the groove-shaped channel communicates with the inner surface of the hole-shaped channel. At the same time, the inner surface that is turned on the outer peripheral side of the piston body is formed by a flat surface.

According to a second aspect of the present invention, in the first aspect of the present invention, the inner surface of the hole-shaped flow path is a single plane .

According to a third aspect of the present invention, in the first aspect of the present invention, the inner surface of the hole-shaped channel is an inverted V-shaped surface as viewed from the center of the piston main body as viewed from the end surface of the piston main body. is there.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the inner surface of the hole-shaped flow path is a V-shaped surface as viewed from the center of the piston main body as viewed from the end surface of the piston main body. .

(Claim 1)
(a) an inner surface f of the hole-shaped flow path manufactured already by sintering or casting or the like to the piston body, the inner surface f1 of the groove-shaped flow path is turned at the outer peripheral side of the piston body with communicating with, the plane Is formed.

  On the other hand, when turning the groove bottom of the outer circumferential groove in the piston body that rotates with the center of the piston body being centered, the bite is concentric with the center of the piston body. It cuts with the circular arc surface which makes.

  For this reason, when the cutting tool cuts the groove bottom of the outer peripheral groove to form a groove-shaped flow path communicating with the hole-shaped flow path, the cutting edge of the bite communicates with the groove-shaped flow path of the hole-shaped flow path. The entire range corresponding to the inner surface f1 (the communication portion between the hole-like channel and the groove-like channel) is not cut at a time. The cutting edge of the cutting tool gradually cuts a portion of the groove bottom of the outer peripheral groove that is thinner than the other portion corresponding to a part of the plane that forms the inner surface f1, and consequently the entire area of the inner surface f1. A communication section extending over to is formed. Since the cutting edge of the cutting tool does not cut the thin skin over the entire range of the communication portion corresponding to all of the inner surface f1 at the groove bottom of the outer peripheral groove at one time, Hard to leave burrs made of a part of thin skin.

(Claim 2 )
(b) By making the inner surface of the hole-like flow path consist of a single plane, the above-mentioned (a) can be realized reliably.

(Claim 3 )
(c) When the inner surface of the hole-shaped flow path forms an inverted V-shaped surface as viewed from the center of the piston body as viewed from the end surface of the piston body, the above-described (a) can be reliably realized.

(Claim 4 )
(d) When the inner surface of the hole-shaped flow path forms a V-shaped surface as viewed from the center of the piston body as viewed from the end surface of the piston body, the above-described (a) can be reliably realized.

FIG. 1 is a schematic diagram showing the principle of the present invention. 2A and 2B show a piston of Reference Example 1, in which FIG. 2A is an end view, FIG. 2B is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a perspective view showing the turning process of the groove-like channel in Reference Example 1. 4A and 4B show a piston of Reference Example 2, in which FIG. 4A is an end view, FIG. 4B is a cross-sectional view taken along line IV-IV in FIG. FIG. 5: shows the piston of Example 1 , (A) is an end elevation, (B) is sectional drawing which follows the VV line of (A), (C) is a perspective view. FIG. 6: shows the piston of Example 2 , (A) is an end elevation, (B) is sectional drawing which follows the VI-VI line of (A), (C) is a perspective view. 7A and 7B show a piston of Example 3 , where FIG. 7A is an end view, FIG. 7B is a sectional view taken along line VII-VII in FIG. 7A, and FIG. FIG. 8: shows the piston of Example 4 , (A) is an end elevation, (B) is sectional drawing which follows the VIII-VIII line of (A), (C) is a perspective view. FIG. 9 is a schematic diagram showing a conventional example.

  FIG. 1A is a schematic view showing a piston 1 for a hydraulic shock absorber manufactured by sintering or casting, where 1A is a piston body, 1B is a valve seat, 1C is an outer peripheral groove, 1D is a hole-like flow path, and 1E. Indicates a channel.

  The piston 1 has a piston body 1A that can be fixed to a piston rod (not shown) inserted into a cylinder (not shown) and that can partition the cylinder into two oil chambers.

  A hole-like channel 1D extends from one end surface of the piston body 1A to an intermediate portion in the axial direction, and the hole-like channel 1D opens into one oil chamber. A groove-like channel 1E is turned on the outer periphery of the piston body 1A, and the groove-like channel 1E communicates with the hole-like channel 1D and opens to the other oil chamber. In the piston 1, a valve seat 1B that protrudes from one end face of the piston main body 1A and surrounds the opening of the hole-shaped flow path 1D (or an annular shape along the outer periphery of the piston main body 1A) is protruded, and this valve seat 1B A disc valve (not shown) that contacts and separates from is provided.

  When the hydraulic shock absorber expands and contracts, the piston 1 slides in the cylinder together with the piston rod. For example, when the other oil chamber is pressurized, the hydraulic oil pressure in the other oil chamber is changed to the groove-like flow path of the piston body 1A. It flows from 1E to the hole-like flow path 1D and thus acts on the disk valve. When the pressure acting on the disc valve becomes larger than the spring force of the disc valve, the outer peripheral edge is bent and deformed to leave the valve seat 1B and open the disc valve. As a result, the hydraulic oil in the other oil chamber flows into one oil chamber, and a damping force is generated due to the throttle resistance between the disk valve and the valve seat 1B during this period, thereby suppressing the expansion and contraction vibration of the hydraulic shock absorber.

  FIGS. 1B and 1C show a piston main body 1A by a lathe tool 2 using a material of the piston 1 in which a valve seat 1B, an outer peripheral groove 1C, and a hole-like flow path 1D have been prepared on the piston main body 1A. A process of turning the outer peripheral groove 1C to produce a groove-like channel 1E communicating with the hole-like channel 1D is shown.

  In FIGS. 1B and 1C, the inner surface f1 of the hole-shaped flow path 1D that has been produced by sintering or casting the piston main body 1A, and the groove-shaped flow path 1E communicates with the inner surface f1. It is formed by a surface other than the circular arc surface concentric with the center c of 1A. In the hole-like channel 1D of FIG. 1B, the inner surface f1 with which the groove-like channel 1E communicates is an arc surface that is not concentric with the center c of the piston body 1A. In the hole-shaped flow path 1D of FIG. 1C, the inner surface f1 with which the groove-shaped flow path 1E communicates consists of a flat surface having a trapezoidal upper side and left and right sides.

  On the other hand, the cutting tool 2 rotates the groove bottom of the outer peripheral groove 1C in the piston main body 1A that is rotated by being centered on the center c of the piston main body 1A. Cutting is performed with an arc surface concentric with the center c.

  For this reason, when the cutting tool 2 cuts the groove bottom of the outer peripheral groove 1C to form the groove-shaped flow path 1E communicating with the hole-shaped flow path 1D, the cutting edge 2A of the bit 2 has the hole-shaped flow path 1D. The entire range corresponding to the inner surface f1 communicating with the groove-shaped flow path 1E (the communication portion P between the hole-shaped flow path 1D and the groove-shaped flow path 1E) is not cut at a time. The cutting edge 2A of the cutting tool 2 gradually cuts out a portion of the groove bottom of the outer peripheral groove 1C that is thinner than the other portion corresponding to a part of the inner surface f1, and eventually extends over the entire inner surface f1. The crossing communication part P is formed. Since the cutting edge 2A of the cutting tool 2 does not cut the thin skin over the entire range of the communication portion P corresponding to the entire inner surface f1 at the groove bottom of the outer circumferential groove 1C, the hole-like flow path 1D and the groove-like flow It is difficult to leave burrs made of a part of thin skin at the communication portion P of the path 1E.

Hereinafter, specific examples of the present invention will be described.
( Reference Example 1) (FIGS. 2 and 3)
FIG. 2 shows a hydraulic shock absorber piston 10 manufactured by sintering or casting. 11 is a piston body, 12 is a valve seat, 13 is an outer peripheral groove, 14 is a hole-like channel, and 15 is a groove-like channel. Reference numeral 16 denotes a valve seat, and 17 denotes a hole-like channel.

  The piston 10 can be fixed to an insertion end of a piston rod (not shown) inserted in a cylinder (not shown), and the cylinder can be divided into two oil chambers (piston rod side oil chamber and piston side oil chamber). It has the piston main body 11 to make.

  A plurality (six in FIG. 2) of hole-shaped flow paths 14 extend from one end surface of the piston body 11 to an intermediate portion in the axial direction, and the hole-shaped flow paths 14 are formed in one oil chamber (for example, piston rod side oil). Open to the room. A groove-like flow path 15 is turned on the outer periphery of the piston body 11, and the groove-like flow path 15 communicates with the hole-shaped flow path 14 and opens to the other oil chamber (for example, the piston-side oil chamber). In the piston 10, a petal shape (a circle along the outer peripheral edge of the piston body 11) surrounding one or more (two in FIG. 2) hole-shaped flow paths 14 on one end surface of the piston body 11. A disc valve (for example, a pressure side disc valve) that makes contact with and separates from the valve seat 12 is provided.

  A plurality (three in FIG. 2) of hole channels 17 extend from the other end surface of the piston body 11 to the step surface on the one end side, and the hole channels 17 open to both oil chambers. In the piston 10, an annular shape (petal shape) along the outer peripheral edge of the piston main body 11 surrounding one or a plurality (three in FIG. 2) of the hole-shaped flow paths 17 on the other end surface of the piston main body 11. However, the valve seat 16 is protruded, and a disc valve (for example, an extension side disc valve) that contacts and separates from the valve seat 16 is provided.

  When the hydraulic shock absorber is compressed, the piston 10 enters the cylinder together with the piston rod, the other oil chamber (piston side oil chamber) is pressurized, and the hydraulic oil pressure in the other oil chamber is grooved in the piston body 11. It flows from the flow path 15 to the hole-shaped flow path 14 and thus acts on the pressure side disk valve. When the pressure acting on the pressure side disk valve becomes larger than the spring force of the pressure side disk valve, the outer peripheral edge of the pressure side disk valve is bent and deformed to leave the valve seat 12 to open the pressure side disk valve. As a result, the hydraulic oil in the other oil chamber (piston side oil chamber) flows into one oil chamber (piston rod side oil chamber), and compression side damping caused by the throttle resistance between the pressure side disk valve and the valve seat 12 during this period. Produce power.

  When the hydraulic shock absorber extends, the piston 10 moves out of the cylinder together with the piston rod, and one oil chamber (piston rod side oil chamber) is pressurized, and the hydraulic oil pressure in this one oil chamber becomes the hole of the piston body 11. Flows into the flow path 17 and thus acts on the extension side disk valve. When the pressure acting on the extension side disk valve becomes larger than the spring force of the extension side disk valve, the outer peripheral edge portion thereof is bent and deformed to leave the valve seat 16 and open the extension side disk valve. As a result, the hydraulic oil in one oil chamber (piston rod side oil chamber) flows to the other oil chamber (piston side oil chamber), and the expansion caused by the throttle resistance between the expansion side disk valve and the valve seat 16 during this period. Side damping force is generated. The expansion / contraction vibration of the piston 10 is suppressed by the compression side damping force and the extension side damping force.

  However, in FIG. 3, the outer peripheral groove 13 (prepared by sintering or casting) of the piston body 11 is gradually turned by a lathe tool (not shown), and each hole channel 14 is formed at the groove bottom of the outer peripheral groove 13. The process of creating the groove-like flow path 15 that opens the hole-shaped communication portion P that communicates with each other, and thus communicates with each hole-shaped flow path 14 is shown. FIG. 3 shows a state in which the opening area of the communication portion P is gradually enlarged as the groove bottom of the outer circumferential groove 13 is gradually deeply turned by repeating the turning.

At this time, the inner surface f1 of the hole-shaped flow path 14 that has been produced by sintering or casting the piston main body 11 and the inner surface f1 communicating with the groove-shaped flow path 15 is concentric with the center c of the piston main body 11. It is formed by a surface other than the arc surface formed. In each hole-like channel 14 of the reference example 1, the inner surface f1 with which the groove-like channel 15 communicates is an arc surface that is not concentric with the center c of the piston body 11.

  On the other hand, the cutting tool turns the groove bottom of the outer peripheral groove 13 in the piston main body 11 that rotates with the center c of the piston main body 11 being rotated. It cuts with a circular arc surface concentric with.

  For this reason, when the cutting tool cuts the groove bottom of the outer peripheral groove 13 to form the groove-shaped flow path 15 communicating with the hole-shaped flow path 14, the cutting edge of the bite has the groove shape of the hole-shaped flow path 14. The entire range corresponding to the inner surface f1 communicating with the flow path 15 (the communication portion P between the hole-shaped flow path 14 and the groove-shaped flow path 15) is not broken at a time. The cutting edge of the cutting tool gradually cuts out a portion of the groove bottom of the outer circumferential groove 13 that is thinner than the other portion corresponding to a part of the inner surface f1, and consequently communicates over the entire inner surface f1. Part P is formed. Since the cutting edge of the cutting tool does not cut through the thin skin over the entire range of the communication portion P corresponding to the entire inner surface f1 at the groove bottom of the outer peripheral groove 13, the hole-shaped flow path 14 and the groove-shaped flow path 15 It is difficult to leave burrs made of a part of the thin skin at the communication part P. Thereby, since generation | occurrence | production of the burr | flash in the communicating part P of the hole-shaped flow path 14 and the groove-shaped flow path 15 can be suppressed, the man-hour which removes a burr | flash becomes unnecessary and productivity of the piston 10 can be improved.

( Reference Example 2) (Fig. 4)
The difference between the piston 10 of the reference example 2 and the reference example 1 is that the piston body 11 is provided with three hole-shaped flow paths 14 and the valve seat 12 surrounds the opening of each one hole-shaped flow path 14. It is to have done.

Also in this reference example, the inner surface f1 of the hole-shaped flow path 14 and the inner surface f1 communicating with the groove-shaped flow path 15 is a surface other than the arc surface concentric with the center c of the piston body 11, in other words, the piston. It was made of an arc surface that is not concentric with the center c of the main body 11. Therefore, also in this reference example, it is possible to suppress the generation of burrs in the communication portion P between the hole-like channel 14 and the groove-like channel 15.

Example 1 (FIG. 5)
The difference between the piston 10 of the first embodiment and the reference example 1 is that the piston body 11 is provided with three hole-shaped channels 14 and the valve seat 12 surrounds the opening of each one hole-shaped channel 14. It is to have done.

  In this embodiment, the inner surface f1 of the hole-like channel 14 and the inner surface f1 communicating with the groove-like channel 15 is a surface other than the arc surface concentric with the center c of the piston body 11, in other words, a single surface. It consisted of one plane. Therefore, also in the present embodiment, it is possible to suppress the generation of burrs in the communication portion P between the hole-like channel 14 and the groove-like channel 15.

Example 2 (FIG. 6)
The difference between the piston 10 of the second embodiment and the reference example 1 is that the piston body 11 is provided with three hole-shaped flow paths 14 and the valve seat 12 surrounds the opening of each one hole-shaped flow path 14. It is to have done.

  In the present embodiment, the inner surface f1 of the hole-like channel 14 and the inner surface f1 communicating with the groove-like channel 15 is a surface other than the arc surface concentric with the center c of the piston main body 11, in other words, the piston. When viewed from the center c of the main body 11, an inverted V-shaped surface (two planes intersecting so as to form an inverted V-shape) is formed. Therefore, also in the present embodiment, it is possible to suppress the generation of burrs in the communication portion P between the hole-like channel 14 and the groove-like channel 15.

Example 3 (FIG. 7)
The difference between the piston 10 of the third embodiment and the second embodiment is that the piston body 11 is provided with six hole-shaped channels 14 and the valve seat 12 surrounds the openings of the two hole-shaped channels 14. It is to have done. Also in this embodiment, the inner surface f1 of the hole-like channel 14 and the inner surface f1 communicating with the groove-like channel 15 is a surface other than the arc surface concentric with the center c of the piston main body 11, in other words, the piston. When viewed from the center c of the main body 11, an inverted V-shaped surface (two planes intersecting so as to form an inverted V-shape) is formed. Therefore, also in the present embodiment, it is possible to suppress the generation of burrs in the communication portion P between the hole-like channel 14 and the groove-like channel 15.

Example 4 (FIG. 8)
The difference between the piston 10 of the fourth embodiment and the reference example 1 is that the piston body 11 is provided with three hole-shaped flow paths 14 and the valve seat 12 surrounds the opening of each one hole-shaped flow path 14. It is to have done.

  In the present embodiment, the inner surface f1 of the hole-like channel 14 and the inner surface f1 communicating with the groove-like channel 15 is a surface other than the arc surface concentric with the center c of the piston main body 11, in other words, the piston. As viewed from the center c of the main body 11, a V-shaped surface (two planes intersecting to form a V shape) was formed. Therefore, also in the present embodiment, it is possible to suppress the generation of burrs in the communication portion P between the hole-like channel 14 and the groove-like channel 15.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

  According to the present invention, in a hydraulic shock absorber piston that turns a groove-like channel provided on the outer periphery of the piston body and communicates with a hole-like channel that extends in the axial direction of the piston body, And the occurrence of burrs at the communicating part of the hole-like channel can be suppressed.

DESCRIPTION OF SYMBOLS 1 Piston 1A Piston main body 1B Valve seat 1C Peripheral groove 1D Hole-shaped flow path 1E Groove-shaped flow path 10 Piston 11 Piston main body 12 Valve seat 13 Outer peripheral groove 14 Hole-shaped flow path 15 Groove-shaped flow path

Claims (4)

A piston body which is fixable to a piston rod inserted into the cylinder and allows the inside of the cylinder to be divided into two oil chambers;
A hole-like flow path extending from one end surface of the piston body to an intermediate portion in the axial direction and opening to one oil chamber;
The center of the piston main body in which the hole-shaped flow path has been prepared is centered, and is turned to the outer periphery of the piston main body, and communicates with the hole-shaped flow path and opens to the other oil chamber In a piston for a hydraulic shock absorber having a flow path,
A hydraulic shock absorber piston, characterized in that an inner surface of the hole-shaped flow path, which is communicated with the groove-shaped flow path and is turned on the outer peripheral side of the piston main body, is formed by a flat surface. The piston for a hydraulic shock absorber according to claim 1, wherein an inner surface of the hole-shaped flow path is formed of a single plane.   2. The hydraulic shock absorber piston according to claim 1, wherein an inner surface of the hole-shaped flow path forms an inverted V-shaped surface as viewed from the center of the piston body in an end surface view of the piston body.   2. The hydraulic shock absorber piston according to claim 1, wherein an inner surface of the hole-shaped flow path forms a V-shaped surface as viewed from the center of the piston body in an end surface view of the piston body.

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