Brake control unit

Abstract: It is an object of the present invention to provide a brake control unit (11) to be used in an anti-lock control or the like which can be mounted in a small space. The present invention is a brake control unit (11) comprising a pump housing block (12) having an accumulator (8) and a pump (9) installed therein, a first and a second solenoid valves (3) of which one ends are connected to one surface of the pump housing block (12) and vertically installed, and a motor M vertically connected to one surface of the pump housing block (12) in parallel with the first and second solenoid valves (3).

Description: This invention relates to a brake control unit to be used in a brake system in a vehicle. More particularly, the present invention relates to a brake control unit installed in a brake liquid supplying line extending from a master cylinder of a vehicle to a wheel cylinder and applied for an anti-lock control for the vehicle or the like. As a prior art of this kind of brake control unit, a brake liquid supplying line extending from a master cylinder M/C to a wheel cylinder W/C in an anti-lock control device will be described in reference to Fig.8. In this figure, a hold valve 3a composed of a normally-opened solenoid valve is placed on a major liquid pressure line 2 extending from the master cylinder M/C connected to a brake pedal 1 to the wheel cylinder W/C. A bypassing liquid circuit 4 for bypassing this hold valve 3a is provided, and a check valve 5 for allowing only a liquid flow from the wheel cylinder W/C to the master cylinder M/C to be flowed in case that a liquid pressure of the wheel cylinder W/C is more than a predetermined value is placed on the bypassing liquid line 4. On a return liquid line 6 extending from the aforesaid wheel cylinder W/C to the master cylinder M/C are placed a decay valve 3b composed of a normally-closed solenoid valve, an accumulator 8 and a pump 9 driven by a motor M, respectively. With such a configuration as above, the hold valve 3a and the decay valve 3b are controlled for their opening or closing operation properly with a control part not shown, thereby a liquid pressure within the wheel cylinder W/C is controlled and then a lock of the wheels in case of braking the vehicle is prevented. In case of a vehicle provided with a vehicle braking auxiliary mechanism such as the aforesaid anti-lock control device, it is a substantial problem to keep an assemblying space for these mechanisms and in case of either a vehicle or a small-sized vehicle having another electronic control mechanism already installed therein, it is sometimes found that there is no piping space for assemblying these mechanisms. A technical concept for making a unit of valves to be used in the anti-lock mechanisms is also disclosed in the specification of U.S.Patent No.3,538,947. Accordingly, both a pump housing and a solenoid housing are provided for each of the solenoid valves and the anti-lock mechanism can be formed into a unit device. However, a structure in which the motor M is fixed to the pump housing becomes a structure in which a portion of the motor M is projected from the side surface of the pump housing and this shows a problem that a large-sized unit itself may not be avoided. From document EP-A1-0,358,127 a modulator unit for use in an anti-lock brake control system has come to be known. This known anti-lock brake control system for an automobile vehicle includes an anti-lock modulator having a single housing structure which accommodates plural sets of flow control valves and solenoid-operated discharge valves, a plurality of plunger pumps and a plurality of reservoirs. The valves in each set are disposed in line and in series-connected fashion with each other. The valve sets and and an electric motor having an eccentric drive shaft for driving the plunger pumps are disposed on respective sides of the longitudinal axis of the plunger pumps. The longitudinal axis of each valve set, that of each plunger plump and that of the eccentric drive shaft are laid perpendicular to one another. It is an object of the present invention to provide a brake control unit which can be installed in a saved spacing. This object is solved according to the invention by a brake control unit having the features set out in independent claim 1. Dependent claims 2 to 4 exhibit advantageous and non-trivial improvements of the subject-matter of claim 1. Initially, in the brake control unit related to the present invention, the first solenoid valve installed between the master cylinder and the wheel cylinder to control a supplying liquid pressure for the wheel cylinder, and the second solenoid valve for controlling a discharged liquid pressure from the wheel cylinder are connected at their one ends to one surface of the pump housing block. An accumulator for accumulating the brake liquid passed through the second solenoid valve and a pump for returning the brake liquid from the accumulator to the passage in the master cylinder are stored in the pump housing block. One end of the motor for driving the pump is connected in parallel with the first and second solenoid valves at one surface of the pump housing block. Secondly, in the brake control unit related to the present invention, is fixed to the pump housing block by a bolt passed from an opposite surface of the pump housing block opposite to the surface to which the motor is connected to the pump housing block. Thirdly, in the brake control unit related to the present invention, to one surface of the pump housing block is fixed the solenoid housing block for use in storing the first and second solenoid valves. Fourthly, in the brake control unit related to the present invention, to the surface of the pump housing block opposite to the surface to which the motor is connected is fixed a traction control unit. Fig.1 is a perspective view for showing as viewed from a right upper side a brake control unit of one preferred embodiment of the present invention. Fig.2 is a perspective view for showing as viewed from a left upper side a brake control unit. Fig.3 is a perspective view for showing as viewed from an upper part of a rear surface a motor fixing structure. Fig.4 is a functional systematic diagram for showing a brake control unit of the preferred embodiment. Figs.5(a) and (b) are perspective views of bar members to be used in the pump housing block and the solenoid housing block. Fig.6 is a perspective view for showing a brake control unit of another preferred embodiment of the present invention as viewed from the right upper direction of the unit. Fig.7 is a perspective view for showing a fixing structure for a traction control unit for a brake control unit of a still further preferred embodiment of the present invention as viewed from an upper part of a rear surface of the unit. Fig.8 is a systematic view for showing a brake liquid supplying system in each of the prior art and the present invention. The present invention is constructed such that an accumulator 8 and a pump 9 are stored within a pump housing block 12, a solenoid valve 3 and a motor M are connected in flush with the pump housing block 12 to constitute a brake control unit, thereby a piping between each of the members such as the solenoid valve 3 or the like can be realized by a punching hole in the pump housing block 12, and the solenoid valve 3 and the motor M are concentrically connected to one surface of the pump housing block 12, resulting in that a small-sized and light-weight brake control unit can be realized. Referring now to Figs.1 to 5, some preferred embodiments of the present invention will be described. The brake control unit 11 of the present invention is placed between the master cylinder M/C and the wheel cylinder W/C, and its function corresponds to a part enclosed by a broken line in Fig.4. Other portions in this figure are similar to that for Fig.8 in the prior art, so that its description will be eliminated. The brake control unit 11 has as its basic unit the pump housing block 12. The pump housing block 12 is made such that an aluminum alloy shown in fig.5(a) is pulled out or pushed to form a bar member 13, the bar member 13 is cut at a predetermined spacing to get block bodies 13a. Predetermined holes are formed in the block bodies 13a and the closing operation is carried for them. In addition, within the housing block 12, the pump 9 and the accumulator 8 are installed through a punching operation. At one surface of the aforesaid housing block 12 are connected the hold valve 3a of the first solenoid valve and the decay valve 3b of the second solenoid valve at their one end. In the following description, as required, the hold valve 3a and the decay valve 3b are totally called as the solenoid valve 3. In the brake control unit 11 of the present preferred embodiment, the two sets of hold valve 3a and the decay valve 3b, i.e. a total four sets of solenoid valves is connected. Accordingly, an anti-lock control in two systems can be carried out in the brake control unit 11. To the other end of the solenoid valve 3, i.e. the end part of the opposite pump housing block is connected the solenoid housing block 14. Such a solenoid housing block 14 is constructed such that the aluminum alloy shown in Fig.5(b) is pulled out or pushed out to form in the same manner as that of the pump housing block 12 to get the bar member 15. The bar member 15 is cut at a predetermined spacing to get some blocks 15a, and a pair of right and left symmetrical blocks are arranged and then a predetermined punching and a closing operation are carried out. As to the pump housing block 12 and the solenoid housing block 14, it is also possible to cast directly the aluminum alloy. However, its die cast mold is complex and costly expensive and a manufacturing accuracy of the material may not be attained and so it is preferable that the pulling-out operation or the extruding molding is carried out. To one surface of the solenoid housing block 14 are opened the pipe connection ports 16a, 16b for the wheel cylinder W/C and a pipe connection port 17 for the master cylinder M/C. The solenoid housing block 14 and the pump housing block 12 are fixed by bolts 19 passing from the rear surface side of the pump housing block 12. A pipe 18 is arranged between the solenoid housing block and the pump housing block 12, and a passage within this pipe may bypass the solenoid valve 3 and become a return liquid passage 6 reaching from the pump 9 to the master cylinder M/C. In the pump housing block 12, the motor M is connected to the same surface as that of the solenoid valve 3. The motor M is applied for driving the pump 9 within the pump housing block 12 and is made such that the pumps 9 in the two systems not shown are driven by a single motor M. As shown in Fig.3, a fixing structure of the motor M in respect to the pump housing block 12 is fastened by the motor fixing bolts 20 passed through the other side (rear surface) of the pump housing block 12 in respect to the connecting end surface. In this way, in the preferred embodiment, the motor M is directly fastened by the motor fixing bolts 20 passed from the other surface of the pump housing block 12 in respect to the connection end surface of the motor M, so that a surplus member such as a fixing flange or the like is not required in a circumferential direction of the extreme end of the motor M, for example, but a relatively large diameter motor M can also be mounted on the surface of the pump housing block surface of small area. In this way, in the preferred embodiment, the anti-lock control mechanism reaching from the master cylinder M/C to the wheel cylinder W/C is made as a single unit structure, and the solenoid valve 3 and the motor M are concentrically arranged at one surface side of the pump housing block 12 acting as a basic body of the unit, resulting in that it is possible to provide the anti-lock device which can be mounted in a small space within a vehicle. The pump driving motor M is fastened with the motor fixing bolts 20 passed from the other surface of the pump housing block 12, thereby it is not necessary to project the fixing flange to the motor M and it is further possible to mount the large-sized large diameter and large output motor M in a small area on the pump housing block 12 and then the anti-lock control mechanism can be realized with a single brake control unit in the two systems. In another preferred embodiment of the brake control unit shown in Fig.6, the solenoid valve 3 is stored within the solenoid housing block 14. In this case, the solenoid housing block 14 has a sufficient size for storing the solenoid valve 3, is abutted against one surface of the pump housing block 12 and further the spacing storing the solenoid valve 3 and the return liquid passage 6 are punched and machined. According to the aforesaid preferred embodiments, the accumulator and the pump are installed within the pump housing block and the solenoid valve and the motor M are connected in the same surface side in respect to the pump housing block to form a unit structure, thereby it is possible to realize the anti-lock control mechanism which can be mounted in a quite small spacing. In a still further preferred embodiment of the brake control unit shown in Fig.7, a traction control unit TC is fixed to the other surface (the rear surface) of the pump housing block 12 shown in Figs.1 to 5, i.e. the surface opposite to the surface to which the motor M is connected.This traction control unit TC is to prevent any slippage of a driving wheel generated in case of starting to drive a vehicle and then a unit formation of these elements enables the brake control unit having an anti-lock control and a traction control to be quite compact one. According to the present invention, it is possible to provide a brake control unit which can be mounted in a quite small space by making a unit formation of the elements as described above.

Claims: A brake control unit (11) installed in a passage provided between a master cylinder (M/C) and a wheel cylinder (W/C), comprising: a) a pump housing block (12); b) a first solenoid valve (3a) being placed in a passage way provided between said master cylinder (M/C) and said wheel cylinder (W/C) so as to control a pressure of brake liquid supplied to said wheel cylinder (W/C); c) a second solenoid valve (3b) for controlling a pressure of the brake liquid discharged from said wheel cylinder (W/C); d) an accumulator (8) for accumulating a brake liquid passed through said second solenoid valve; e) a motor (M); and f) a pump (9) driven by said motor (M) for returning the brake liquid from said accumulator (8) to said master cylinder (M/C); characterized in that g) the first solenoid valve (3a) is one end connected to one surface of said pump housing block (12); h) said second solenoid valve (3b) is one end connected to said one surface of said pump housing block (12) to which said first solenoid valve (3) is connected; i) said accumulator (8) is installed within said pump housing block (12); j) said motor (M) is one end connected to said one surface of said pump housing block (12) in parallel with said first and second solenoid valves (3a, 3b); and k) said pump (9) is arranged within said pump housing block (12). A brake control unit (11) according to claim 1, wherein said motor (M) is fixed to said pump housing block (12) by bolts passed from a surface opposite to the surface to which said motor (M) is connected. A brake control unit (11) according to claim 1 or 2, further comprising a solenoid housing block (14) fixed to said one surface of said pump housing block (12) and storing said first and second solenoid valves (3a, 3b). A brake control unit (11) according to claim 1 or 2, further comprising a first solenoid housing block (14) fixed to said one surface of said pump housing block (12) and storing said first and second solenoid valves (3a, 3b), a second solenoid housing block (14) fixed to said one surface of said pump housing block (12) and storing said first and second solenoid valves (3a, 3b), wherein said motor (M) is arranged between said first solenoid housing block (14) and said second solenoid housing block (14) on said plane surface of said pump housing block (12). A brake control unit (11) according to any one of claims 1 to 4, further comprising a traction control unit (TC) fixed to a surface opposite to the surface of said pump housing block (12) to which said motor (M) is connected.

Inventors: SEKIGUCHI AKIHIKO, SEKIGUCHI, AKIHIKO
Applicants: AKEBONO BRAKE IND, AKEBONO BRAKE INDUSTRY CO., LTD.
Application year: 1991
Main classification: B60T8
IPC codes: B60T8