This application is based on Japanese Patent Application Nos. 2007-40888 filed on Feb. 21, 2007, and 2007-290723 filed on Nov. 8, 2007, the disclosures of which are incorporated herein by reference.
The present invention relates to a hydraulic brake pressure control apparatus, which is incorporated into a vehicle hydraulic braking system having an electronic control function.
A hydraulic brake pressure control apparatus is incorporated into a vehicle hydraulic braking system having an electronic control function, wherein the hydraulic brake pressure control apparatus is composed of a hydraulic unit having a pump, an electric motor for driving the pump, and electromagnetic valves for controlling fluid pressure, and an electronic control unit. The electronic control unit is so composed that an electric circuit board having control circuits is arranged in a casing. The hydraulic brake pressure control apparatus of this kind is disclosed in patent publications, for example, Patent (PCT) Publication No. 2004-506572, and Japanese Patent Publication No. H11-43031.
In the hydraulic brake pressure control apparatus disclosed in the above Patent (PCT) Publication No. 2004-506572, an electronic controller (an electronic control unit) is held by a holder firmly fixed to a vehicle body, and a valve block (a hydraulic unit) is resiliently supported by the holder being separated from the electronic controller.
In the hydraulic brake pressure control apparatus disclosed in the above Japanese Patent Publication No. H11-43031, a coil supporting plate is fixed to an open side of a cover (casing) for electromagnetic valves, wherein the cover (casing) covers one end of a hydraulic unit. Coils for the electromagnetic valves are resiliently arranged and held between the cover and the coil supporting plate.
In the recent hydraulic brake pressure control apparatus, more and more components having sophisticated functions are incorporated. Functional components sensitive against vibrations, for example, semiconductor devices for control, sensors for detecting vehicle behaviors and fluid pressures, and so on, are mounted on a circuit board of the electronic control unit. Electrical connecting portions to be connected to terminals formed on the circuit board are also sensitive against the vibrations.
An electric motor for driving a pump, electromagnetic valves for fluid pressure control, and so on, which generate impacts and vibrations, are incorporated into a housing of a hydraulic unit. In case of a piston-type pump, the piston-type pump itself becomes one of sources for generating the vibrations. And the vibrations thus generated are likely to be transferred to the circuit board of the electronic control unit.
A structure, disclosed in the above Patent (PCT) Publication No. 2004-506572, has an object to decrease vibrations to be transferred from the hydraulic unit to the electronic control unit, wherein impacts and/or vibrations are attenuated by a buffering element of a resiliently supporting portion. Accordingly, affection by the vibration to the functional components and connecting portions of electric circuits can be suppressed to a smaller amount. However, a reliability of a connecting portion between the electronic controller and the valve block (e.g. a reliability of a seal at the open end of the cover, a reliability of electrical connection between the electronic controller and the valve block, and so on) may become insufficient, because the electronic controller is separated from the valve block.
On the other hand, in the apparatus disclosed in the above Japanese Patent Publication No. H11-43031, a sealing member is interposed between an open-side periphery of the cover for the electromagnetic valves and a sealing surface of the valve block, and the cover for the electromagnetic valves is fixed to the valve block of the hydraulic unit by means of bolts. Accordingly, a reliability of the connecting portion between the electronic control unit and the hydraulic unit is assured. In addition, vibration to be generated by the coils becomes smaller, because the coils for the electromagnetic valves are held between the coil supporting plate fixed to the open side of the cover for electromagnetic valves and a resilient member supported by the cover, so that movement of the coils is restricted. However, according to this conventional apparatus, the coil supporting plate is necessary in addition to the sealing member, which may increase manufacturing cost.
Furthermore, the resilient member is interposed between the coils of the electromagnetic valves and the cover for the electromagnetic valves, and the coils are held between the resilient member and the coil supporting plate. Accordingly, the vibration is transferred from the valve block to the circuit board via the cover for the electromagnetic valves.
The present invention is made in view of the foregoing problems, and has an object to provide a hydraulic brake pressure control apparatus, wherein vibration transfer from the hydraulic unit to the electronic control unit can be effectively suppressed in order to protect functional components mounted on a circuit board and electrical connecting portions formed on the circuit board.
According to a feature of the present invention, a hydraulic brake pressure control apparatus for a vehicle has a hydraulic unit, which has a housing, and an electric motor and electromagnetic valves incorporated into the housing. The apparatus further has a casing, which has fixing portions and is fixed to one end of the housing by bolts, wherein the bolts are inserted into through-holes formed at the fixing portions. The apparatus further has a circuit board, which has a control circuit and is arranged in the casing. A resilient member is disposed between the housing and the casing, such that the housing and the casing are entirely separated from each other, and a part of the resilient member is also disposed between the bolts and the casing.
The hydraulic brake pressure control apparatus according to the present invention may have one or combination of the following features, as the case may be:
The above mentioned washer may be integrally formed with the collar, or may be separately formed from the collar.
According to the hydraulic brake pressure control apparatus of the present invention, the resilient member is disposed between the housing of the hydraulic unit and the casing for the electromagnetic valves, such that the housing and the casing are entirely separated from each other. Furthermore, a part of the resilient member is disposed between the bolt and the casing, such that the bolt and the casing are entirely separated from each other. As a result, vibration transfer from the housing to the casing is carried out via the resilient member, which has a function of absorbing vibration, so that vibration to be transferred is attenuated by the resilient member. The vibration is, therefore, hardly transferred to the casing.
Furthermore, a sealing portion for fluid tightly sealing a gap between the housing and the casing at their respective sealing surfaces as well as a coil supporting portion for supporting a coil of the electromagnetic valve is formed in the resilient member. Accordingly, a special sealing member and a special coil supporting member are no longer necessary, to thereby reduce a number of parts and manufacturing cost.
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
An embodiment of the present invention will be explained with reference to the attached drawings.
The hydraulic unit 10 incorporates a pump (not shown) into a housing 11, which is made of a metal such as aluminum alloy. An electric motor 12 for operating the pump is attached to a side portion of the housing 11. Fluid passages, which are connected to a suction port and an outlet port of the pump, as well as a discharge port to a reservoir, are formed in the inside of the housing 11. In addition, an electromagnetic valve for controlling fluid pressure of a wheel cylinder (not shown), and multiple electromagnetic valves for opening and closing fluid passages are incorporated into the housing 11. Furthermore, a pressure sensor and a damper may be incorporated into the housing 11, as the case may be. A coil 14 of an electromagnetic valve 13, which is incorporated into the housing 11, is shown in
The ECU 20 has a resin casing 21 covering one end of the housing 11 (
The printed circuit board 22 has a control circuit (not shown), functional components (electronic parts, such as ECU, sensors, and so on) forming the control circuit, and connecting portions for electrical circuits. It is preferable to apply less mechanical vibrations to those parts (portions) and components.
A resilient member 1, such as rubber, is provided between the resin casing 21 and the housing 1. A detailed structure of the resilient member 1 is shown in
An outer portion of the resilient member 1, which is surrounded by an outer periphery and a two-dot-chain line in
As shown in
The bolt 25 has a screw portion 25a and a head portion 25b provided at one end of the screw portion 25a and having a larger diameter than that of the screw portion 25a. A washer 6 is disposed between a bearing surface of the head portion 25b and a surface of the fixing portion 23 facing to the bearing surface. In the drawing (
The resilient member 1 is attached to one side of the housing 11, such that the coil supporting portions 3 of the resilient member 1 are arranged between the coils 14 and the housing 11 in order to assemble the coils 14. The coils 14 are inserted into the recesses formed at the coil supporting portions 3, so that the coil 14 is supported by a bottom surface 3a and an inner peripheral surface 3b of the recess. As a result, movements of the coils 14 in axial and radial directions are restricted.
The resin casing 21 is then fixed to the housing 11, wherein each of the second resilient portions 4b, which projects from the flat base plate 1a, is inserted into the respective through-hole 24 formed in the resin casing 21. Next, the metal collar 5 is inserted into the first interposed portion 4c of the second resilient portion 4b from a side opposite to the housing 11. And the bolt 25 is inserted into the metal collar 5 and screwed into the housing 11.
The second interposed portions 4d, which are formed at the projecting end of the first interposed portion 4c (the second resilient portion 4b) and divided into multiple portions in the circumferential direction, are pushed by the washer 6 (the flange of the metal collar 5), so that the second interposed portions 4d are bent in a radial pattern as shown in
According to such a structure, the resin casing 21 is separated from the housing 11 even at the fixing portions 23, and also separated from the bolt 25 by means of the resilient member 1. As a result, the vibration transfer from the housing 11 to the resin casing 21 is carried out through the resilient member 1, so that the vibration to be transferred is attenuated due to vibration absorbing performance of the resilient member 1.
In the electronic control unit (ECU) 20 shown in the drawings, the printed circuit board 22 is assembled and the cover 21a is attached to complete the assembling of the apparatus.
It is more preferable to have a shape for the vibration transfer suppressing portion 4 of the resilient member 1, as shown in
More exactly, an inner-diameter enlarging portion 7 is formed at the second resilient portion 4b, such that an inner diameter of the second resilient portion 4b becomes larger toward a top forward end of the second resilient portion 4b. For example, in
Furthermore, as shown in
As shown in
Alternatively, the second interposed portion 4d may be formed as a separate member from the first interposed portion 4c of the second resilient portion 4b, as shown in
As explained above, the sealing portion 2, the coil supporting portions 3 and the vibration transfer suppressing portions 4 are integrally formed in the resilient member 1, so that labor hours for manufacturing and assembling processes as well as manufacturing cost can be reduced.
Number | Date | Country | Kind |
---|---|---|---|
2007-040888 | Feb 2007 | JP | national |
2007-290723 | Nov 2007 | JP | national |