JP4160582B2 - Brake fluid pressure control unit for in-vehicle devices - Google Patents

Description

  The invention of this application relates to a brake fluid pressure control unit of an in-vehicle device including control of a brake system such as an antilock brake device, a vehicle behavior control device, and a traction control device.

  As this type of brake fluid pressure control unit, one described in Patent Document 1 below is known.

  In this brake hydraulic pressure control unit, as shown in FIG. 10, a rectangular parallelepiped base block 1 made of an aluminum material is provided with a hydraulic circuit (not shown) including hydraulic equipment such as a pump. On the first base surface 1a and the second base surface 1b, which are two opposite surfaces on the block 1, are mounted a motor 2 for operating the pump and an electronic base block 3 for controlling electromagnetic valves and other devices. Yes. In addition, the base block 1 is provided with a reservoir 8 in which a piston 6 and an urging means 7 are accommodated in a space surrounded by the cylinder hole 4 and the lid member 5, and hydraulic fluid (brake fluid) in the hydraulic circuit is provided. ) Is temporarily stored by the reservoir 8.

The cylinder hole 4 of the reservoir 8 is formed in the second base surface 1b to which the electronic board block 3 is attached, and the lid member 5 attached to the opening of the cylinder hole 4 projects into the cover 3a of the electronic board block 3. Yes. The lid member 5 is formed in a bottomed cylindrical shape from an iron-based metal from the viewpoint of thinning and strength, and the piston 6 can freely slide in the cylindrical wall. Further, the space between the cylinder hole 4 and the lid member 5 is divided into a liquid chamber 9 a and an atmospheric chamber 9 b by the piston 6, and the atmospheric chamber 9 b is a vent hole (not shown) provided at the bottom of the lid member 5. )) To communicate with the outside of the block.
International Publication WO99 / 25594

  However, in this brake fluid pressure control unit, the base block 1 is made of an aluminum material, whereas the lid member 5 attached to the cylinder hole 4 is made of an iron-based metal. 5, so-called galvanic corrosion (dissimilar metal contact corrosion, galvanic corrosion) is likely to occur. In particular, if there is air (oxygen) and an electrolyte such as a brake fluid around the contact portion, Furthermore, it becomes easy to be promoted. For this reason, in the conventional apparatus, the cylinder hole 4 is formed in the second base surface 1 b of the base block 1, and the lid member 5 is arranged in the cover 3 a of the electronic board block 3, so that the periphery of the lid member 5 is obtained. This prevents adhesion of brake fluid and rainwater.

  In recent years, there has been a demand for a compact brake fluid pressure control unit in order to improve on-vehicle performance. Of the base block 1, a motor 2 and an electronic board block 3 which are large block parts are arranged. It is considered to arrange the reservoir 8 on a surface other than the second base surfaces 1a and 1b.

  However, since the surfaces other than the second base surface 1b on which the electronic base block 3 is disposed are directly exposed to the outside of the block without being covered by the cover 3a or the like, the lid member 5 of the reservoir 8 has a dedicated cover or the like separately. Unless installed, brake fluid, rainwater, etc. are likely to adhere. In other words, the exposed surface on the base block 1 is likely to be exposed to rainwater and the like, and the brake fluid is likely to scatter or wrap around when the connection pipe is removed during maintenance. Naturally, the rainwater, the brake fluid, and the like easily adhere to the outer surface of the lid member 5 installed on the exposed surface.

  Furthermore, because the reservoir 8 is structured so that when the piston 6 moves back and forth, the outside air around the vent hole is actively sucked into the lid member 5, so that the brake that has oozed out from the sliding gap of the piston 6. The liquid adheres to the inner surface of the lid member 5 and, in combination with the outside air (oxygen) induced around the liquid, the electric corrosion of the inner surface of the lid member 5 is likely to proceed. If moisture or salt is contained in the outside air that has been put in, the progress of electrolytic corrosion is also facilitated by this.

  Therefore, it is difficult to install the reservoir 8 on a surface other than the installation surface (second base surface 1b) of the electronic base block 3 with the cover 3a. It can be realized that it is difficult to achieve both electric corrosion prevention. Further, as means for preventing electrolytic corrosion, it is conceivable that the lid member 5 made of an iron-based metal is subjected to a surface treatment and attached to the cylinder hole 4, but in this case, the surface treatment itself increases the manufacturing cost. When the cover member 5 is attached to the cylinder hole 4 by caulking or the like, the surface treatment is easily peeled off, and it is difficult to completely prevent electric corrosion.

  Accordingly, the invention of this application is to provide a brake hydraulic pressure control unit for an in-vehicle device that can increase resistance to metal corrosion such as electric corrosion without causing an increase in the size of the entire device and an increase in manufacturing cost. is there.

  The present invention has been devised in view of the state of the prior art, a cylinder hole formed in a base block made of an aluminum material, a lid member attached to an opening of the cylinder hole, and the cylinder A piston that is housed in a space between the hole and the lid member and that divides the interior into a liquid chamber and an air chamber; and the piston is interposed between the piston and the lid member so that the piston faces the bottom of the cylinder hole In the brake fluid pressure control unit of the in-vehicle device having a reservoir provided with a biasing means, the lid member is formed of an aluminum material, and the end of the lid member is thinned toward the outer peripheral tip. And a concave stepped portion for supporting the bottom surface of the flange portion in the cylinder hole, and an opening edge of the cylinder hole is provided on the upper surface of the flange portion by caulking punches. The upper surface of the engaging portion of the opening edge formed by the pressing force of the front end surface of the caulking punch when caulking to the tapered surface is formed so as to be substantially parallel to the bottom surface of the concave stepped portion. It is said.

  In the case of this invention, since the base block and the lid member are in contact with the same aluminum material, even if brake fluid or moisture adheres to the outer surface or inner surface of the lid member in an outside atmosphere, the progress of electrolytic corrosion is ensured. Can be prevented. In addition, at this time, it is not necessary to cover the periphery of the lid member with a cover or to perform a surface treatment on the lid member, so that it is possible to simultaneously improve the vehicle mountability by reducing the size of the device and reduce the manufacturing cost.

  The opening edge of the cylinder hole may be caulked over the entire taper surface of the flange or may be partially caulked. When the entire area is caulked, it is possible to reliably prevent the caulking portion from being deformed even when a large load is applied to the lid member from the piston or the like. In addition, when partial caulking is performed, caulking distortion that appears on the side surface orthogonal to the caulking surface of the base block is reduced, so that the width of the base block can be reduced so that the side surface is close to the cylinder hole. Become.

  Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.

  This embodiment is an example of an anti-lock brake device that is one of in-vehicle devices that controls a brake system, and a brake fluid pressure control unit (hereinafter referred to as a “fluid pressure control unit”) is a hydraulic fluid feed. A rectangular parallelepiped base block 11 on which a hydraulic circuit including various hydraulic devices such as a supply pump 10 is mounted, and a first base surface 11a and a second base surface which are two surfaces facing in opposite directions on the base block 11. A pump drive motor 12 and an electronic base block 13 for electronic device control, which are respectively attached to the base surface 11b, are provided.

  A pipe (not shown) on the master cylinder side and a pipe (not shown) on the wheel cylinder side are respectively connected to the base block 11, and the hydraulic pressure on the wheel cylinder side is appropriately controlled by a hydraulic circuit in the block 11. It is supposed to do. Specifically, the hydraulic pressure control unit appropriately opens and closes a passage in the hydraulic circuit by an electromagnetic valve 14 provided across the base block 11 and the electronic base block 13, and in the wheel cylinder according to the slip state of the wheel. The pressure is reduced, held, or increased again. In addition, a pair of reservoirs 15 for temporarily storing hydraulic fluid is provided in the hydraulic circuit of the base block 11 so that the hydraulic fluid in each reservoir 15 is appropriately returned to the master cylinder side by the operation of the pump 10. It has become. In the case of this embodiment, the pump 10 is constituted by a plunger pump as shown in FIG. 2, and an eccentric cam 16 that is rotationally driven by a motor 12 reciprocates a plurality of plungers 17, thereby performing pump operation. It has become.

  The base block 11 is entirely formed of an aluminum material, and is designed so that the upper surface side in FIG. A pair of cylinder holes 18 and 18 are formed on the lower surface of the base block 11 in a direction perpendicular to the width direction between the first and second base surfaces 11a and 11b. 1-3, a piston 19 that slides in the cylinder hole 18 and a coil spring 20 that is an urging means for urging the piston 19 toward the bottom of the cylinder hole 18 are accommodated. In addition, a lid member 21 made of the same aluminum material as the base block 11 is attached to the open end of each cylinder hole 18.

  The piston 19 in each cylinder hole 18 is provided with a seal ring 22 on the outer periphery, and the space between the cylinder hole 18 and the lid member 21 is divided into a liquid chamber 23 and an atmospheric chamber 24. The liquid chamber 23 located on the bottom side of the cylinder hole 18 is connected to a passage outside the figure in the hydraulic circuit, and the air chamber 24 is connected to the outside of the unit through a vent hole 25 formed in the bottom wall of the lid member 21. Communicating with

  A concave step 26 is formed in an annular shape at the opening edge of the cylinder hole 18 as shown in an enlarged view in FIG. 3, and a lid member 21 is pressed and fixed to the bottom surface of the concave step 26 by a fixing means described later. Yes. The entire lid member 21 is formed in a bottomed cylindrical shape, and an outward flange 28 extends in an annular shape at the end of the cylindrical wall 27, and the cylindrical wall 27 is fixed to the concave stepped portion 26. It protrudes from the lower surface of the base block 11. The entire lid member 21 is formed by forging.

  The flange 28 is formed so that the outer diameter thereof is slightly smaller than the inner diameter of the concave step portion 26, and the tapered surface 28a (see FIG. 3) is formed so that the outer surface thereof becomes thinner toward the outer peripheral tip on the upper surface side (the cylindrical wall 27 side). .) Is formed. Further, the outer peripheral edge portion of the flange 28 protrudes outward from the diameter of the cylinder hole 18 and is in contact with the bottom surface of the concave step portion 26, but the inner peripheral edge portion of the flange 28 has a diameter larger than the inner peripheral surface of the cylinder hole 18. A cylindrical wall 27 located on the inner side in the direction and connected to the flange 28 is formed to have a diameter smaller than the diameter of the cylinder hole 18. Therefore, the inner peripheral edge of the flange 28 faces the end surface of the piston 19 and abuts against the piston 19 when the piston 19 descends more than the set stroke, thereby restricting excessive displacement of the piston 19.

  By the way, the flange 28 of the lid member 21 is fixed by an annular locking portion 29 (plastic deformation portion) extending on the upper edge of the concave step portion 26 as shown in FIGS. As shown in FIG. 5, the locking portion 29 is shaped by caulking the entire upper edge of the concave step portion 26 with a punch 30 having a flat tip end surface, but the flange 28 has an upper surface to be fixed. Since it is formed in a tapered shape, plastic deformation of the caulking portion is smoothly performed along the tapered surface 28 a of the flange 28. The lid member 21 thus caulked and fixed to the concave step portion 26 supports the reaction force of the coil spring 20 and reliably restricts the excessive displacement of the piston 19.

  This hydraulic pressure control unit configured as described above covers the reservoir 15 with a cover or the like on the surface other than the first and second base surfaces 11a and 11b on the base block 11 (the surface on the lower side when mounted on the vehicle). However, since the lid member 21 of the reservoir 15 is formed of the same aluminum material as that of the base block 11, for example, brake fluid, moisture, or the like may be present on the outer surface or inner surface of the lid member 21 in an outside air atmosphere. Even if it adheres, electrolytic corrosion does not occur between the base block 11 and the lid member 21. Therefore, the corrosion of the reservoir 15 can be reliably prevented without increasing the cost due to an increase in the size of the hydraulic pressure control unit or surface treatment.

  Further, in this hydraulic pressure control unit, the entire lid member 21 is formed by forging. Therefore, the rigidity and strength of the lid member 21 are increased by work hardening by forging, and the deformation of the lid member 21 and the attachment strength are reduced. It is possible to sufficiently reduce the thickness of the lid member 21 without incurring the above. Therefore, although the lid member 21 is formed of an aluminum material, a significant increase in the thickness of the lid member 21 is not caused as compared with the conventional lid member 21 formed of an iron-based metal. The increase can be minimized.

  In the case of this hydraulic pressure control unit, the lid member 21 is formed in a bottomed cylindrical shape, and the cylindrical wall 27 of the lid member 21 protrudes from the base block 11, so that the depth L of the cylinder hole 18 (see FIG. 3) is shallower, and the amount of overhang on the lower surface side of the base block 11 can be reduced to that extent. Therefore, the whole hydraulic pressure control unit is made more compact from these things, and it becomes difficult to interfere with other parts, and the vehicle mountability of the unit is further improved.

  In particular, in this embodiment, a portion of the reservoir 15 where the piston 19 does not slide (a portion that contributes only to expansion and contraction of the coil spring 20) is formed on the lid member 21 side, and that portion is formed on the base block 11. Therefore, the thickness of the lid member 21 can be made sufficiently thin to reduce interference between the lid member 21 and other surrounding members. Then, since the occupied volume of the lid member 21 on the lower surface side of the base block 11 is reduced, an insulator rubber (not shown) is arranged in a space without the lid member 21 on the lower surface of the block 11, and the insulator rubber. The block 11 can be installed on the mounting surface in the engine room via the. Therefore, the lid member 21 protruding from the base block 11 is disposed without waste in the dead space on the lower surface side of the block 11 that is originally provided for interposing the insulator rubber.

  Furthermore, in this hydraulic pressure control unit, since the tapered surface 28a is formed on the flange 28 of the lid member 21 that is caulked and fixed to the concave step portion 26, the following operational effects can be obtained.

  That is, when the flange 28 of the lid member 21 is supported by the locking portion 29 formed by caulking, the flange 28 receives the load F received from the piston 19 as a shear load at a portion indicated by a broken line in FIG. At this time, if the lid member 21 is made of an iron-based metal like the conventional one, it can sufficiently withstand the load F even if the flange 28 is formed thin as shown in FIG. Although the strength can be obtained, when the lid member 21 is formed of an aluminum material, it is not possible to obtain the same strength with the same thickness as the ferrous metal, so the flange 28 needs to be further thickened.

  However, if the thickness of the flange 28 is increased, the height H of the concave step portion 26 formed in the opening of the cylinder hole 18 must be increased as shown in FIG. The protruding amount of the block 11 becomes large, which causes a problem that the base block 11 cannot be sufficiently downsized.

  On the other hand, in this embodiment, since the flange 28 of the lid member 21 is tapered toward the outer peripheral tip, the flange 28 shows the load F from the piston 19 as shown in FIG. Thus, it can receive as a shear load in the thickest broken-line part. For this reason, the shear strength equivalent to that of the thick flange 28 shown in FIG. 6B can be obtained without increasing the height of the concave step portion 26, and the lid member 21 is formed of an aluminum material. Nevertheless, it is possible to reliably support the load from the piston 19 with sufficient strength.

  Incidentally, in the above embodiment, the annular locking portion 29 is formed by caulking the entire upper edge of the concave step portion 26 of the cylinder hole 18, but as shown in FIGS. A plurality of arc-shaped locking portions 129 may be formed by partially caulking a plurality of locations on the upper edge. 7 and 8, the same parts as those in the embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals.

  In this case, as shown in FIG. 7, the non-caulking portion of the locking portion 29 that is not shaped is arranged so as to be close to the first and second base surfaces 11 a and 11 b of the base block 11, thereby causing distortion due to caulking. Is less likely to appear on the first and second base surfaces 11a and 11b, which are the attachment surfaces of the large block component. Therefore, the width w of the first and second base surfaces 11a and 11b of the base block 11 can be further reduced, and the hydraulic pressure control unit can be further downsized. Further, in the case of partial caulking, since the caulking load can be small, it is possible to extend the life of the caulking tool and reduce the tool cost.

  Further, as shown in FIG. 9, if an arcuate cross section R is formed at the tip portion and the root portion of the flange 28 of the lid member 21, stress concentration at the flange 28 portion can be more reliably prevented, The strength of the lid member 21 can be further increased.

The longitudinal cross-sectional view which shows one Embodiment of invention of this application. Sectional drawing corresponding to FIG. 1A-A cross section which shows the same embodiment. The expanded sectional view of the reservoir | reserver part of FIG. 2 which shows the same embodiment. The B arrow directional view of FIG. 3 which shows the same embodiment. The expanded sectional view which shows the crimping state of the embodiment. Typical sectional drawing explaining caulking of the embodiment. The rear view corresponding to FIG. 3 which shows other embodiment of invention of this application. Sectional drawing corresponding to CC cross section of FIG. 7 which shows the same embodiment. The expanded sectional view of the caulking part which shows other embodiment of invention of this application. The side view of the hydraulic-pressure control unit which shows the prior art.

Explanation of symbols

11 ... Base block 15 ... Reservoir 18 ... Cylinder hole 19 ... Piston 20 ... Coil spring (biasing means)
21 ... Lid member 23 ... Liquid chamber 24 ... Air chamber 25 ... Vent

Claims (1)

A cylinder hole formed in a base block made of an aluminum material, a lid member attached to the opening of the cylinder hole, and a space between the cylinder hole and the lid member accommodates the interior of the liquid chamber and the atmosphere. A brake fluid for an in-vehicle device having a reservoir comprising: a piston that is partitioned into a chamber; and a biasing means that is interposed between the piston and the lid member and biases the piston toward the bottom of the cylinder hole. In the pressure control unit,
While forming the lid member with an aluminum material and providing a tapered flange portion that becomes thinner toward the outer peripheral tip at the end of the lid member,
A concave stepped portion that supports the bottom surface of the flange portion is provided in the cylinder hole,
When the opening edge of the cylinder hole is caulked to the taper surface on the upper surface of the flange portion by caulking punch, the upper surface of the locking portion of the opening edge formed by the pressing force of the front end surface of the caulking punch is A brake fluid pressure control unit for an in-vehicle device, wherein the brake fluid pressure control unit is formed so as to be substantially parallel to a bottom surface of the concave stepped portion.

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