JP4487692B2 - Center valve for master cylinder - Google Patents

Description

  The present invention relates to a center valve for a master cylinder used as a hydraulic pressure generation source for a hydraulic brake or a hydraulic clutch of a vehicle.

  For example, this type of master cylinder 1 will be described with reference to FIG. 1 showing an embodiment of the present invention. A piston 3 can be moved in a cylindrical axis direction in a cylindrical body 2 whose end is closed (movable forward and backward). ) And a connection port 4 to each hydraulic device such as a hydraulic control modulator is formed in the body 2 and a reservoir tank 5 is provided. A center valve 20 is provided at the tip of the piston 3, and the center valve 20 opens and closes based on the forward and backward movement of the piston 3 through the push rod 6 by stepping on and releasing the brake petal. a is fed, and the hydraulic fluid a from each hydraulic device is returned to the reservoir tank 5.

  The center valve 20 has a valve box 21 formed at the front end of the piston 3, and a valve seat 30 and a valve body 40 are provided in the hydraulic fluid passage 22 in the cylinder axis direction in the valve box 21. . As shown in FIG. 9, the valve seat 30 is provided by fitting a valve seat member 32 having an elastic sheet 31 fitted on the outer peripheral surface thereof into the flow passage 22 of the valve box 21, and the elastic sheet 31 is formed by the valve body 40. Is composed of a front surface portion 31a that is in pressure contact and an outer peripheral portion 31b that extends in the flow direction of the flow passage 22 from the outer peripheral edge of the front surface portion 31a. The valve body 40 includes a truncated cone-shaped valve body main body 41 and a shaft 42 extending in the cylinder axis direction from the center of the valve body main body 41, and the shaft 42 is slidably inserted into the valve seat member 32, The body main body 41 (the valve body side valve seat 41a) can be brought into contact with and separated from the elastic sheet 31 (the front surface portion 31a) of the valve seat 30.

  In the center valve 20, as shown in FIGS. 9 to 10, when the valve body 40 (valve body main body 41) is pressed against the valve seat 30 (elastic sheet 31), the front surface portion 31a of the elastic sheet 31 is pushed inward. As a result, the valve seat member 32 may be caught between the front surface (metal seal surface) 32a and the rear surface of the valve body main body 41 (valve body side valve seat 41a). When this action is repeated, the front inner end 31c of the elastic sheet 31 is broken into pieces. This tearing leads to functional deterioration of the elastic sheet 31.

  Further, even when the load from the brake petal is lost (the pressing force to the brake petal is released) and the piston 3 shown in FIG. 1 returns to the initial state, the master like the VSC (vehicle stability control) is used. Regardless of the action of the cylinder 1 itself, the inside of the cylinder body 2 may be in a pressurized state by another hydraulic device. In this case, even if the brake petal is pushed back to the initial position and the valve body 40 and the valve seat 30 begin to separate, the pressure difference between the left and right chambers in the master cylinder body 2 with the center valve 20 as a boundary (left chamber pressure> right chamber pressure). ) Is generated, and the valve body 40 is still in pressure contact with the valve seat 30 while the front surface portion 31a of the elastic sheet 31 is drawn inward (on the shaft 42 side) due to the differential pressure. The inner end 31c bites between the front surface of the valve seat member 32 and the rear surface of the valve body main body 41 and is sandwiched between the two, and is repeatedly broken up.

As a technique for preventing this tearing, as shown in FIG. 11, an annular groove 51 is formed on the entire inner periphery of the front surface portion 31 a of the elastic sheet 31, and the valve body 40 is formed in the valve seat 30 as shown in FIG. 12. When pressed, the deformation due to the pressing of the front surface portion 31a of the elastic sheet 31 is absorbed (accommodated) in the groove 51 to prevent the tearing (see Patent Document 1).
JP 2002-302029 A paragraph 0012 same paragraph

  Although the annular groove 51 shown in FIG. 11 has a certain effect, the deformation of the elastic sheet 31 at the time of the pressure contact of the valve body 40 to the valve seat 30 causes not only the front surface portion 31a but also the outer peripheral portion 31b.

  However, as can be understood from FIG. 11, the rear end of the outer peripheral portion 31 b of the conventional elastic sheet 31 is in close contact with the back wall step portion 3 d of the flow passage 22 in the valve box 21. However, since the volume is hardly reduced, the deformation force acts on the front part 31a which can move freely, and the front part 31a is moved forward (valve element 40 side) and inside (the valve body 40 side). Shaft 42 side).

  For this reason, the annular groove 51 cannot sufficiently absorb (accommodate) the deformation, and the inner end 31c of the front surface portion 31a bites between the valve seat member 32 and the rear surface of the valve body main body 41 and is sandwiched between the two. May occur. If the annular groove 51 is made larger, the amount of deformation accommodated can be increased and tearing can be effectively prevented. However, the large annular groove 51 leads to a decrease in volume of the front surface portion 31a, leading to deterioration in sealing performance and durability. For this reason, the shape (size) of the annular groove 51 is limited.

  An object of the present invention is to prevent the elastic sheet from being broken by another means.

In order to achieve the above object, the present invention absorbs the deformation of the front portion of the elastic sheet by the deformation of the outer peripheral portion thereof.
If the deformation of the elastic sheet due to the pressure contact of the valve body is absorbed by the deformation of the outer peripheral part, the absorption direction is the pressing direction (pressure contact direction), so the front part is also dragged in that direction, and the inner end of the front part is the valve seat The degree of biting between the front surface of the member and the rear surface of the valve body main body and being sandwiched between the two is minimized.
Moreover, even when the elastic sheet is pulled in due to the differential pressure between the left and right chambers in the master cylinder body with the center valve as the boundary, such as VSC, the hydraulic pressure in the left chamber, which has a high pressure, is increased. Since the front surface portion is pulled by pushing, the inner end of the front surface portion is also pulled (retracted) in that direction, and is not caught between the front surface of the valve seat member and the rear surface of the valve body main body.
The outer peripheral portion of the elastic seat is mainly responsible for the function of attaching the elastic seat to the valve seat member, and even if a deformation accommodating portion is formed on the outer peripheral portion, it affects the deterioration of the sealing performance compared to the front portion. Less is.

Specifically, a valve box is formed at the piston tip in the master cylinder body, a valve seat and a valve body are provided in the hydraulic fluid flow passage in the valve box, and the valve seat has an elastic sheet on the outer peripheral surface. The fitted valve seat member is fitted into the flow passage of the valve box, and the elastic sheet is composed of a front surface portion to which the valve body is pressed and an outer peripheral portion extending from the outer peripheral edge of the front surface portion in the flow direction of the flow passage. In the master cylinder center valve that contacts and separates the valve body from the valve seat by the movement of the piston in the master cylinder body, a gap is formed behind the outer periphery of the elastic seat, and the valve body is pressed against the valve seat. At this time, it is possible to adopt a configuration in which deformation of the elastic sheet due to the pressure contact in the pressure contact direction is released to the gap. The voids do not include voids due to C-cut or R-cut at the corners where it is not possible to release the deformation in the press-contact direction.

  The gap can be formed in the middle of the outer periphery of the elastic sheet, and when the valve body is pressed against the valve seat, the deformation of the elastic sheet due to the pressure contact can be released to the gap. In short, the gap may be any position as long as it is capable of absorbing deformation, such as behind and in the middle of the elastic sheet.

In the center valve for a master cylinder having these configurations, the valve seat is provided with a shaft in which the flow direction of the hydraulic fluid passage is in the length direction, the shaft is fitted in the valve box, and the shaft is fitted by fitting the shaft. It is advisable to position them.

In this way, since the valve seat is positioned by the shaft, for example, when the valve seat (elastic seat) is asymmetrical in the longitudinal direction, there is no risk of mounting the valve seat in the wrong direction and the valve seat is centered. It can be done easily and reliably.
At this time, the length of the shaft is set so that the shaft fits in the valve box before the elastic sheet is fitted (press-fitted) into the hydraulic fluid passage (in the valve box) of the valve box. After the seat is positioned (centered) on the shaft center, the elastic sheet may be smoothly press-fitted (fitted) into the working fluid flow path.

  As described above, the present invention absorbs the deformation of the front portion of the elastic sheet by the deformation of the outer peripheral portion thereof. It is possible to effectively suppress galling. For this reason, the valve action becomes reliable over a long period of time, and a highly reliable master cylinder center valve can be obtained.

  FIG. 1 to FIG. 4 show an embodiment. As described above, in this embodiment, a piston 3 is placed in a cylindrical master cylinder body 2 which is closed at one end through a packing 7 so as to be movable forward and backward in the cylinder axis direction. The master cylinder body 2 is provided with a connection port (an inflow / outflow port for hydraulic fluid a) 4 to each hydraulic device such as a hydraulic control modulator, and a reservoir tank 5 is provided in the master cylinder body 2. The piston 3 is recessed in the middle and has a small diameter, and a vertical hole 3a penetrating vertically is formed in the length direction (cylinder axis direction). A pin 8 fixed to the master cylinder body 2 is slidably fitted in the vertical hole 3a, and the piston 3 advances and retreats without rotating. The middle recess 3b of the piston 3 communicates with the reservoir tank 5 through a hole 5a.

  A center valve 20 which is a characteristic part of the present invention is provided at the tip of the piston 3. A return spring 9 is provided between the closing wall in the master cylinder body 2 and the piston 3, and when the brake petal is depressed from the state shown in FIG. 1, the push rod 6 is interposed as shown in FIG. Then, the piston 3 advances (left direction in the figure), and based on this, the center valve 20 is closed by the action described later, and the hydraulic fluid a is sent to each of the hydraulic devices. On the other hand, when the depression of the brake petal is released, the return spring 9 causes the piston 3 to retreat as shown in FIGS. 2 to 1 (right direction in the figure). The hydraulic fluid a from each hydraulic device returns to the reservoir tank 5.

The center valve 20 has a valve box 21 formed by a tip of the piston 3 and a cover 23 of the piston 3, and a valve seat 30 and a valve element in the hydraulic fluid passage 22 in the cylinder axis direction in the valve box 21. 40 is provided. The hydraulic fluid passage 22 passes through the valve box 21 and reaches the vertical hole 3a of the piston 3. Two chambers (two chambers on the left and right) in the master cylinder body 2 separated by the piston 3 by the hydraulic fluid passage 22 are provided. Communicate.

  The valve seat 30 is provided by fitting a valve seat member (collar) 32 having an elastic sheet 31 on the outer peripheral surface thereof into the hydraulic fluid passage 22 of the valve box 21, and the elastic body 31 is pressed against the valve body 40. It consists of a front surface portion 31a and an outer peripheral portion 31b extending from the outer peripheral edge of the front surface portion 31a in the flow direction of the flow passage 22. The elastic sheet 31 is attached and fixed to the valve seat member 32 by rubber vulcanization, rubber casting or the like. The hydraulic fluid passage 22 is composed of a large diameter portion 22a (left side in FIG. 1) and a small diameter portion 22b, and the valve seat 30 extends from the large diameter portion 22a to the small diameter portion 22b until the valve seat member 32 contacts the back wall step portion 22c. It is press-fitted and attached (see FIGS. 3 and 4).

A shaft 34 is formed integrally with the valve seat member 32, and the valve seat 30 is positioned and fixed at a required position by inserting the shaft 34 into the hole (the working fluid flow passage 22) of the piston 3. Due to the presence of the shaft 34, there is no fear that the valve seat 30 is attached in the wrong front and rear, and the centering of the valve seat 30 can be easily and reliably performed.
Note that the length of the shaft 34 is such that the shaft 34 is in contact with the elastic sheet 31 before reaching the small diameter portion 22b of the flow passage 22 of the valve box 21 (before contacting the large diameter portion 22a and the step portion of the small diameter portion 22b). The elastic seat 31 is smoothly pressed into the small diameter portion 22b of the flow passage 22 after the valve seat 30 is positioned (centered) after being set to fit into the hole 3e of the piston 3. To.

  The valve body 40 includes a truncated cone-shaped valve body main body 41 and a shaft 42 extending in the cylinder axis direction from the center of the valve body main body 41, and a valve spring 43 is interposed between the valve body main body 41 and the cover 23. The valve spring 40 is biased toward the valve seat 30 by the valve spring 43. The shaft 42 is slidably inserted into the valve seat member 32, and the valve body main body 41 (valve body side valve seat 41a) moves on the valve opening / closing moving shaft to the elastic seat 31 (the front surface portion 31a) of the valve seat 30. It is possible to contact and separate. Further, the shaft 42 is formed with a groove 42a extending over the entire outer periphery of the shaft 42, and the hydraulic fluid a travels between the valve box 21 and the vertical hole 3a through the groove 42a.

  The front surface portion 31a of the elastic seat 31 of the valve seat 30 protrudes from the front surface of the valve seat member 32 by a required amount. When the valve body 40 is pressed against the valve seat 30 and the center valve 20 is closed, first, the valve body side valve seat 41a. Abuts against the front surface portion 31a of the elastic seat, and then abuts against the front surface 32a of the valve seat member 32 while deforming the elastic seat 31. For this reason, the center valve 20 is closed by an elastic seal and a metal seal.

An annular groove (gap) 33 around the shaft 42 is formed in the side wall of the valve box 21 behind the rear end surface of the outer peripheral portion 31b of the elastic sheet 31, and the valve body 40 is connected to the valve seat 30 shown in FIGS. At the time of pressure contact, the pressure load on the elastic sheet 31 due to the pressure contact or the deformation load of the elastic sheet 31 due to the differential pressure between the left and right chambers in the master cylinder body with the center valve as a boundary is deformed into the gap of the annular groove 33. (The deformation of the elastic sheet 31 is released into the annular groove (gap) 33). This deformation causes the elastic sheet 31 to be deformed in the cylinder axis direction, so that the front surface portion 31a is also pulled in that direction (outer peripheral portion 31b side), and the inner end 31c of the front surface portion 31a is the front surface of the valve seat member 32 ( The metal seal surface) 32a and the rear surface of the valve body main body 41 (the valve body side valve seat 41a) do not bite.

  This embodiment is configured as described above. In the state shown in FIG. 1, the valve body shaft 42 abuts against the pin 8 to position the valve body 40, and the valve body main body 41 (the valve body side valve seat 41a) is moved to the valve seat. The center valve 20 is opened away from 30 (elastic sheet 31), and the hydraulic fluid a can freely flow between the reservoir port 5 from the connection port 4 through the master cylinder body 2.

  When the brake petal is stepped on from this state, as shown in FIG. 2, the piston 3 advances via the push rod 6, and based on this, the valve body 40 also moves to the left and the shaft 42 leaves the pin 8. . At the initial stage, the valve spring 40 approaches the valve seat 30 without moving by the valve spring 43, and eventually comes into contact with the valve seat 30 (elastic sheet 31) to close the center valve 20, and the center valve 20 maintains its state. And move together with the piston 3. When the center valve 20 is closed, the hydraulic fluid a is sent from the master cylinder body 2 to each hydraulic device based on the movement of the piston 3. When the valve is closed, the elastic sheet 31 is effectively prevented from being broken by the presence of the annular groove (gap) 33.

On the other hand, when the depression of the brake petal is released, the return spring 9 causes FIG.
As shown in FIG. 4, when the piston 3 moves backward and the valve body shaft 42 of the center valve 20 abuts against the pin 8 as the valve 3 moves backward, the valve body 40 stops moving, and the valve seat 30 is moved further by the backward movement of the piston 3. The center valve 20 is retreated and separated from the valve body 40 (valve body main body 41) to open. With this opening, the working fluid a returns to a state where it can freely flow between the connection port 4 and the reservoir tank 5 through the master cylinder body 2. In this state, even if the master cylinder body 2 is pressurized by a hydraulic device such as VSC and the valve body 40 is pressed against the valve seat 30, the elastic sheet 31 similarly has an annular groove (gap). The presence of 33 effectively prevents tearing of the front surface portion 31a.

  FIG. 5 shows another embodiment. In this embodiment, a retainer 10 is provided on the closed wall side in the master cylinder body 2, and a valve shaft rod 44 from the valve body 40 is guided to the retainer 10. The front end 44 a of 44 is slidably fitted in the guide 11. The valve body 40 is moved on the valve opening / closing movement shaft by the retainer 10 (guide 11) via the rod 44, and the tip end portion 44a abuts against the wall of the retainer 10 (the end of the guide 11) to position the valve body 40. Therefore, the shaft 42 and the pin 8 are omitted.

  In this embodiment, in the illustrated state, the distal end portion 44a of the rod 44 abuts against the side wall of the retainer 10 (guide 11) to position the valve body 40, and the valve body main body 41 (valve body side valve seat 41a) is The center valve 20 is opened away from the seat 30 (elastic sheet 31), and the hydraulic fluid a can freely flow between the connection port 4 and the reservoir tank 5 through the master cylinder body 2.

  When the brake petal is stepped on from this state, the valve body 40 initially approaches the valve seat 30 without moving by the valve spring 43, and eventually comes into contact with the valve seat 30 (elastic sheet 31), and the center valve 20 is closed. The center valve 20 maintains that state and moves while inserting the rod 44 together with the piston 3 into the guide 11, and sends the hydraulic fluid a from the master cylinder body 2 to each hydraulic device. Similarly, the elastic sheet 31 is effectively prevented from being cut off by the presence of the annular groove (gap) 33 in the pressurized state by other hydraulic devices at the time of closing and opening the valve. .

  On the other hand, when the depression of the brake petal is released, the piston 3 is retracted by the return spring 9, and the valve body 40 is positioned when the tip end portion 44a of the rod 44 contacts the wall of the retainer 10 (guide 11). When the piston 40 is moved further and the piston 3 is further retracted, the valve seat 30 is retracted and separated from the valve body 40 (valve body main body 41), and the center valve 20 is opened. With this opening, the working fluid a returns to a state where it can freely flow between the connection port 4 and the reservoir tank 5 through the master cylinder body 2.

  Since the elastic sheet 31 is asymmetrical in that the front surface portion 31a is provided only at the front edge of the outer peripheral portion 31b, the outer peripheral portion 31b is smoothly deformed toward the gap 33 behind the other, but other modes can be considered. . For example, as shown in FIG. 6, the rear end 31 d of the outer peripheral portion 31 b can be expanded and fitted into the valve seat member 32. Also, as shown in FIG. 7, various modes such as retreating the rear end of the outer peripheral portion 31 b to the front side without providing the annular groove 33 can be considered as the deformation absorbing gap of the elastic sheet 31. In short, it is sufficient if there is a gap 33a that absorbs deformation of the outer peripheral portion 31b. Also in the mode of FIG. 7, the rear end portion 31 d of the outer peripheral portion 31 b can be bulged and fitted into the valve seat member 32 as indicated by a chain line.

Further, as shown in FIG. 8, the gap 33a can be provided in the middle of the outer peripheral portion 31b of the elastic sheet 31, and in this case, the gap 33a is formed on the outer surface as in (a) and on the inner surface as in (b). Or, it can be formed inside (b) like the chain line. At this time, the outer circumference of the air gap 33a is preferable, but it may be intermittent. Also, the depth (size), the position in the length direction (cylinder axis direction) and the number of the gaps 33a may interfere with the function of the elastic sheet 31. It is optional as long as it does not occur. In addition, the aspect of the space | gap 33 (33a) of FIG.3, FIG.7, FIG.8 and the surrounding groove | channel 51 of the said gazette can each be used together suitably.

  Incidentally, when the embodiment shown in FIG. 1 and FIG. 5 and the embodiment in which the elastic sheet 31 is changed to the elastic sheet 31 in the form of FIG. 9 are compared under the same conditions, the latter breaks up early. However, the former was not broken up over a long period of time, and high reliability could be obtained.

Partially cutaway front view of one embodiment Operational diagram of the embodiment Action diagram when center valve is opened in the same embodiment Action diagram when the center valve is closed Cut front view of another embodiment Sectional drawing of the principal part of other embodiment Sectional drawing of the principal part of other embodiment Sectional drawing of the principal part of other embodiment Cross section of the main part of the conventional example Operation diagram of the conventional example Cross-sectional view of the main part of another conventional example Operation diagram of the conventional example

Explanation of symbols

1 Master cylinder 2 Master cylinder body 3 Piston 4 Hydraulic fluid inflow / outflow port (connection port)
5 Reservoir tank 10 Retainer 20 Center valve 21 Center valve valve box 22 Working fluid flow passage 22a Working fluid flow passage large diameter portion 22b Working fluid flow passage small diameter portion 30 Valve seat 31 Elastic seat 31a Elastic seat front portion 31b Elastic seat outer peripheral portion 32 Valve seat member 33 annular groove (gap)
33a Air gap 34 Valve seat shaft 40 Valve body 41 Valve body main body 41a Valve body side valve seat a Hydraulic fluid

Claims (4)

A valve box (21) is formed at the tip of the piston (3) in the master cylinder body (2), and a valve seat (30) and a valve body (in the hydraulic fluid passage (22) in the valve box (21) ( 40), and the valve seat (30) is provided by fitting a valve seat member (32) with an elastic sheet (31) fitted on the outer peripheral surface thereof into the flow passage (22) of the valve box (21). The elastic sheet (31) is composed of a front surface portion (31a) to which the valve body (40) is pressed and an outer peripheral portion (31b) extending from the outer peripheral edge of the front surface portion (31a) in the flow direction of the flow passage (22), In the master cylinder center valve (20) that contacts and separates the valve body (40) from the valve seat (30) by the movement of the piston (3) in the master cylinder body (2),
An annular groove (33) is formed in the side wall of the valve box (21) behind the rear end face of the outer peripheral portion (31b) of the elastic sheet (31), and the outer peripheral portion of the elastic sheet (31) is formed by the annular groove (33). (31b) A gap (33) is formed in the rear, and when the valve body (40) is pressed against the valve seat (30), deformation of the elastic sheet (31) in the pressure contact direction due to the pressure contact is formed in the gap (33). A center valve for a master cylinder, characterized in that it escapes to A valve box (21) is formed at the tip of the piston (3) in the master cylinder body (2), and a valve seat (30) and a valve body (in the hydraulic fluid passage (22) in the valve box (21) ( 40), and the valve seat (30) is provided by fitting a valve seat member (32) with an elastic sheet (31) fitted on the outer peripheral surface thereof into the flow passage (22) of the valve box (21). The elastic sheet (31) is composed of a front surface portion (31a) to which the valve body (40) is pressed and an outer peripheral portion (31b) extending from the outer peripheral edge of the front surface portion (31a) in the flow direction of the flow passage (22), In the master cylinder center valve (20) that contacts and separates the valve body (40) from the valve seat (30) by the movement of the piston (3) in the master cylinder body (2),
The elastic sheet (31) is attached to the outer peripheral part (31b) of the valve seat member (32) by rubber casting, and a gap (33a) is inserted in the middle of the outer circumferential part (31b) of the elastic sheet (31) in the flow direction. ), And when the valve body (40) is pressed against the valve seat (30), deformation of the elastic sheet (31) in the pressure contact direction due to the pressure contact is released to the gap (33a). The center valve for the master cylinder.   The valve seat (30) is provided with a shaft (34) in which the flow direction of the hydraulic fluid flow passage (22) is in the length direction, and the shaft (34) is fitted into the valve box (21). The center valve for a master cylinder according to claim 1 or 2, characterized in that the valve seat (30) is positioned by being fitted.   The length of the shaft (34) is such that the elastic seat (31) is fitted into the valve box (21) and the valve seat (30) is centered before being pressed into the valve box (21). The center valve for a master cylinder according to claim 3, wherein the center valve is set.

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