JPH02175361A - Brake hydraulic pressure control device - Google Patents

Abstract

PURPOSE:To obtain more accurate brake pressure control by inserting a free piston closely into a No.2 cylinder hole formed in the same axis as a No.1 cylinder hole, into which a spool driven by an electromagnetic solenoid is closely inserted, and connected through the No.1 cylinder hole. CONSTITUTION:Modulators 1FR and 1FL for front right and front left wheel brake devices BFR and BFL and a modulator 1R commonly used for rear right and left wheel brake devices BRR and BRL are positioned in parallel with each other in a common housing 5. The housing 5 is composed of No.1 and No.2 cylindrical bodies 5a and 5b with No.1 and No.2 cylinder holes 12 and 13, respectively. Each of the modulators 1FR, 1FL, and 1R is constructed of a spool 10, inserted closely into the No.1 cylinder hole 12 and excited axially by an electromagnetic solenoid 11 positioned at one end of the housing, and a free piston 20 inserted closely into the No.3 cylinder hole 13. The free piston 20 restricts the rear movement limit position of the spool to a back pressure chamber 22 side by the use of a partition 14 as a stopper.

Description

[Detailed description of the invention] A1 Purpose of the invention (1) Industrial application fields The present invention relates to a brake hydraulic control device.

(2) Prior Art Conventionally, such a brake hydraulic pressure control device has been known to control the hydraulic pressure output from a mask cylinder according to the amount of depression of the brake pedal, as disclosed in, for example, Japanese Utility Model Application Publication No. 62-77068. Controlled by brake hydraulic control device
and supplies it to the brake equipment.

(3) Problems to be Solved by the Invention However, the conventional hydraulic braking hydraulic control device described above has a complicated configuration and cannot be said to be capable of precise control.

The present invention has been made in view of the above circumstances, and provides a brake hydraulic pressure control device that controls the brake hydraulic pressure by electrical control, thereby simplifying the configuration and enabling more precise brake pressure control. The purpose is to

B1 Structure of the Invention (1) Means for Solving the Problems According to the present invention, an electromagnetic solenoid that exerts a thrust according to an input amount of electricity is interlocked and connected to one end, and a hydraulic pressure is applied to counter the thrust. A spool formed with the control hydraulic pressure generation chamber facing the other end is located between a hydraulic pressure supply position where the hydraulic pressure supply source is communicated with the control hydraulic pressure generation chamber and a hydraulic pressure release position where the hydraulic pressure of the control hydraulic pressure generation chamber is released. A free piston is slidably fitted into the first cylinder body so as to be movable in the axial direction, and has a back pressure chamber communicating with the control oil pressure generation chamber and an output chamber communicating with the brake device on both end faces.The free piston slides into the second cylinder body. The second cylinder body is fitted freely, and a stopper is provided on the second cylinder body to restrict the retracting limit position of the free piston toward the back pressure chamber side.

(2) Effect According to the above configuration, by making the oil pressure in the control oil pressure generation chamber correspond to the thrust of the electromagnetic solenoid, the oil pressure in the control oil pressure generation chamber is made to correspond to the amount of electricity input to the trli1 solenoid, and its By applying the hydraulic pressure in the control hydraulic pressure generation chamber to the back pressure chamber, the free piston is driven, and the hydraulic pressure in the output chamber is applied to the brake device, and the braking hydraulic pressure acting on the brake device is converted into the amount of electricity manually applied to the 11 magnetic solenoid. In addition, it is possible to prevent air generated in the control hydraulic pressure generating chamber from entering the brake device.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1, a left front wheel brake device BFL and a right front wheel brake device BFI are installed on the left front wheel and right front wheel of a vehicle, respectively. A modulator I FLI I Fl is individually interposed between the hydraulic pressure supply source S and the oil tank T, and a left rear wheel brake device B*L is installed on the left rear wheel and the right rear wheel, respectively. And both brake devices BIIL, B are installed between the right rear wheel brake device ffB□ and the hydraulic pressure supply source S and oil tank T.
+u+ common modulator 1. are interposed, and each brake device B F L + B□, BIL,
Braking oil pressure is supplied to B□.

Each brake device B FL, B FRI B 111
1 B IIm includes a cylinder 2 and a piston 3 slidably fitted into the cylinder 2, and is adapted to brake hydraulic pressure supplied to a brake hydraulic pressure chamber 4 defined between the cylinder 2 and the piston 3. A braking force is generated by the corresponding movement of the piston 3.

The hydraulic supply source S includes a hydraulic pump P that pumps hydraulic oil from an oil tank T, an achiemulator A that is connected to the hydraulic pump P, and a pressure switch PS that controls the operation of the hydraulic pump P. .

Each modulator Lrt, 1□, III is arranged in parallel to each other in a common housing 5,
Their modulators I FL, I rw, .
1 stomach has basically the same configuration, only the structure of the modulator IFL will be described in detail below, and a detailed explanation of the modulators 1□, ], l will be omitted.

The housing 5 has a single input port leading to the hydraulic supply IS and a single release boat 7 leading to the oil tank T.
Three output boats 8FL, 8 leading to the brake hydraulic chamber 4
□, 8. The output boats 8FL and 8□ are respectively arranged corresponding to the front wheel brake devices 2BrL and B□, and the remaining output boats 8. 1 is arranged to commonly correspond to the rear wheel brake device B ILI B IK.

The modulator IFL includes a spool lO that is slidably fitted into the housing 5, and a linear solenoid 11 as an electromagnetic solenoid that is attached to the housing 5 to press the spool 10 in the axial direction. The control I! is interlocked and connected to one end of the spool 10 and faces the other end of the spool 10. A hydraulic pressure generation chamber 17 is formed. The spool 10 maintains the communication state between the input port leading to the hydraulic pressure supply source S and the control hydraulic pressure generation chamber 17, and the communication state between the control hydraulic pressure generation chamber 17 and the release boat 7 through the linear solenoid 11 at one end in the axial direction. The switching is performed in response to a change in the axial position due to the magnitude relationship between the thrust force of the hydraulic pressure chamber 17 and the hydraulic pressure of the control hydraulic pressure ordering chamber 17 acting on the other end in the axial direction.

In the housing 5, a first cylinder body 5a having a first cylinder hole 12 and a second cylinder body 5b having a second cylinder hole 13 are integrally connected with the first and second cylinder holes 12.13 on the same axis. A partition wall 14 separating the first and second cylinder holes 12, 13 is provided in the continuous portion of both cylinder bodies 5a, 5b. A spool 10 is slidably fitted into the first cylinder hole 12 .

The linear solenoid 11 is attached to the outer surface of one side (the right side in FIG. 1) of the housing 5, and the drive rod 15 of the linear solenoid 11 is connected to the first cylinder hole 1.
an insertion hole 16 bored in the housing 5 through one end of the housing 5;
is coaxially inserted into the first cylinder hole 12. Further, a control hydraulic pressure generation chamber 1 is provided between the other end of the spool 10 and the partition wall 14.
7 is defined, and the control oil pressure generating chamber 17 includes a spool 10.
A return spring 18 is housed therein, which urges the linear solenoid 11 toward one end in the axial direction, that is, toward the linear solenoid 11. Therefore spool 10
The drive rod 15 is always in contact with one end of the
The spool lO and the near solenoid 11 are interlocked and connected.

A free piston 20 is slidably fitted into the second cylinder hole 13. This free piston 20 and housing 5
There is an output chamber 21 communicating with the output port 8FL, and
A back pressure chamber 22 is defined which communicates with the control oil pressure generation chamber 17 via a communication hole 19 formed in the partition wall 14, and an output chamber 21
A return spring 23 that urges the free piston 20 toward the partition wall 14 is housed in. When hydraulic pressure is generated in the control hydraulic pressure generation chamber 17 in response to the operation of the linear solenoid 11, the hydraulic pressure acts on the back of the free piston 20, and thereby the hydraulic pressure generated in the output chamber 21 is transferred to the output boat 82.
This acts on the brake hydraulic pressure chamber 14 of the brake device BFL. Furthermore, the partition wall 14 also functions as a stopper that restricts the retracting limit position of the free piston 20 toward the back pressure chamber 22 side.

The spool 10 is provided with lands 25 and 26 that form an annular groove 24 therebetween, and the annular groove 24 is connected to the control oil pressure generation chamber 17 in the sliding ring 5 regardless of the axial position of the spool lO. A communicating passage 27 is bored. Further, on the inner surface of the first cylinder hole 12, an annular recess 28 that allows communication between the input port and the annular groove 24 and an annular recess 29 that allows communication between the release boat 7 and the annular groove 24 are spaced apart in the axial direction. When the spool 10 moves to the left toward the partition wall 14 and is in the hydraulic pressure supply position where the annular recess 28 communicates with the annular groove 24, the annular recess 29 connects to the land 2.
5, and when the spool 10 moves right from the hydraulic pressure supply position to the hydraulic release position where the annular recess 29 communicates with the annular groove 24, the annular recess 28 is closed by the land 26, and the hydraulic pressure supply position and In the intermediate position of the hydraulic release position, the re-annular recesses 28,29 are respectively closed by lands 25,26.

That is, the spool 10 communicates with the back pressure chamber 22 at the back of the free piston 20 through the communication hole 19, the control oil pressure generation chamber 17, and the communication passage 27, and the annular groove 24 communicates with the annular recess 28. It moves in the axial direction between a hydraulic pressure supply position where hydraulic pressure is supplied from the hydraulic pressure supply source S and a hydraulic pressure release position where the annular groove 24 is communicated with the release boat 7 and the back pressure chamber 22 is communicated with the oil tank T. The pressing force of the near solenoid 11 that acts on all ends of the spool 10 in the axial direction acts toward the oil pressure supply position, and the oil pressure applied to the other axial end of the spool 10 by the oil pressure of the control oil pressure generation chamber 17. acts toward the hydraulic release position.

When the back pressure chamber 22 at the back of the free piston 20 is released, the free piston 20 retreats to the retraction limit where it abuts the partition wall 14, and when the free piston 20 is at the retraction limit, the auxiliary input boat communicates with the output chamber 21. 31 is housing 5
to be drilled. The auxiliary input boat 31 is for supplying braking hydraulic pressure to the hydraulic chamber 21 according to the depression operation of the brake pedal 32 when the hydraulic pressure supply source S fails.The auxiliary input boat 31 includes an auxiliary hydraulic pressure supply means. 33
Auxiliary output Portro 1 is connected.

The auxiliary hydraulic pressure supply means 33 includes a braking hydraulic pressure generating section 34 that can generate braking hydraulic pressure according to the amount of depression of the brake pedal 32, and a braking hydraulic pressure generated by the braking hydraulic pressure generating section 34 when the hydraulic pressure supply aS fails, and outputs the braking hydraulic pressure from the modulator IFL. It also includes a switching valve section 35 that is operated to switch the supply to the chamber 21 .

The braking oil pressure generating section 34 is made up of a piston 38 that is slidably fitted into a third cylinder hole 37 provided in a cylinder body 36, and a load cell 39 is attached to the piston 38.
A brake pedal 32 is connected via. Thus, a reaction chamber 40 is defined between the cylinder body 36 and the piston 38 on the side opposite to the brake pedal 32, and the piston 38 is urged in the direction of increasing the volume of the reaction chamber 40. A spring 41 is housed. In addition, the cylinder body 36 has a reaction chamber 40 with a maximum volume, that is, the brake pedal 32
A boat 42 is provided which communicates with the reaction chamber 40 when the piston 38 moves to the left as much as possible without depressing the engine, and the boat 42 communicates with the oil tank T.

The switching valve section 35 is composed of a spool valve body 44 slidably fitted into a main body 43, and the main body 43 is integrally and coaxially connected to the cylinder body 36 of the braking oil pressure generating section 34. Ru. Furthermore, a fourth cylinder hole 45 is bored in the main body 43 coaxially with the third cylinder hole 37, and the spool valve body 44 is slidably fitted into the fourth cylinder hole 45. Further, a partition wall 46 separating the third and fourth cylinder holes 45 is provided in the continuous portion of the cylinder body 36 and the main body 43, and this partition wall 46 has coaxial communication with the third and fourth cylinder holes 37.45. A hole 47 is drilled.

A spring chamber 48 is defined between the spool valve body 44 and the partition wall 46, and a hydraulic pressure source hydraulic chamber 49 is defined between the end wall of the fourth cylinder hole 45 and the spool valve body 44 on the opposite side from the partition wall 46. defined. The spring chamber 4 communicates with the reaction chamber 40 through a communication hole 47, and within this spring chamber 48 is a spring 50 that urges the spool valve body 44 in the direction of increasing the volume of the spring chamber 48. is stored.

A hydraulic power source boat 51 communicating with the hydraulic power source hydraulic chamber 49 is bored in the main body 43, and this hydraulic power source boat 51 is connected to the hydraulic pressure supply source S. Therefore, the hydraulic oil from the hydraulic supply source S is supplied to the hydraulic source hydraulic chamber 49, and the hydraulic pressure from the hydraulic supply source S acts on the spool valve body 44 in the left direction, and the spring force of the spring 50 and the reaction chamber The hydraulic pressure caused by the hydraulic pressure generated at 40 acts in the right direction, and when the hydraulic pressure supply source S is operating normally, the spool valve body 44 moves to the left until it comes into contact with the partition wall 46, and the hydraulic pressure source S When S fails and the oil pressure in the oil pressure source oil pressure chamber 49 decreases, the spool valve body 44 separates from the partition wall 46 and moves to the right.

An annular groove 52 closer to the spring chamber 48 and an annular groove 53 closer to the oil pressure source hydraulic chamber 49 are provided on the outer surface of the spool valve body 44 with an interval between them. Further, on the inner surface of the fourth cylinder hole 45, in order from the spring chamber 48 side, annular recesses 54, 55,
56 and 57 are provided with a space between them. Furthermore, the annular recess 54 is arranged to communicate with the annular groove 52 only when the spool valve body 44 is in the leftward movement position, and the annular recess 55 is arranged so as to communicate with the annular recess 53 only when the spool valve element 44 is in the leftward movement position. , the annular recess 56 is arranged to always communicate with the annular groove 53 regardless of the axial position of the spool valve element 44, and the annular recess 57 is arranged to communicate with the annular groove 53 only when the spool valve element 44 is in the rightward movement position. will be established. Furthermore, the spool valve body 44
, an oil passage 5 communicating with the reaction chamber 40 via a spring chamber 48 is provided.
8 is bored, and the core oil passage 58 is opened to the annular groove 52 and constantly communicates with the annular recess 57 (opened to the outer surface of the spool valve body 44 near the hydraulic pressure source hydraulic chamber 49.

The main body 43 of the switching valve section 35 has a boat 59 communicating with the annular recess 54 and a release boat 6 communicating with the annular recess 55.
0 and an auxiliary capo 61 communicating with the annular recess 56 are bored. The drift boat 59 is communicated with the accumulator At, the release boat 60 is communicated with the oil tank T, and the auxiliary output port 1 is communicated with the auxiliary input boat 31.

In such an auxiliary hydraulic pressure supply means 33, when the hydraulic pressure from the hydraulic pressure supply source S is acting on the hydraulic source hydraulic chamber 49, the spool valve body 44 is in the leftward movement position, and in this state, the reaction chamber 40 is in the spring chamber. On the 4th, the oil passage 58, the annular groove 52, the annular recess 54, and the boat 59 communicate with the Akiemulator A2. Moreover, in this state, the auxiliary output port I
and release boat 60 are in communication with each other via annular recess 56, annular groove 53, and annular recess 55.

Further, when the oil pressure in the oil pressure source oil pressure chamber 49 decreases, the spool valve body 44 moves to the right position. It is communicated with an auxiliary human-powered boat 31 via the output port 1.

In FIG. 2, the linear solenoid 11 of the modulator IFL includes a pair of coils 63a and 63b, and generates a thrust corresponding to the total amount of electricity input to the coils 63a and 63b. That is, the third
As shown in the figure, the linear solenoid 11 generates a thrust according to the total amount of excitation current It~I of both coils 63a and 63b, or the voltage when the resistance is constant, and the stroke range consists of Now, when the total excitation current is I and the constant is K, the linear solenoid 1
The thrust force F generated at 1 is expressed as F=K·1. Further, the oil pressure of the control oil pressure generation chamber 17 is set as Pw, and the oil pressure of the control oil pressure generation chamber 1
When the pressure receiving area of the spool 10 facing 7 is Sc,
The hydraulic pressure f acting on the spool 10 is expressed as f=sc-Pw. Therefore, when F=K・I>Sc−Pw, the spool 10 moves to the left hydraulic pressure supply position,
When F=-1<Sc-Pw, the spool 10 moves to the right hydraulic release position.

By moving the spool 10 in the axial direction in accordance with the magnitude relationship between the thrust force F and the hydraulic pressure f, hydraulic oil is supplied from the hydraulic pressure supply source S to the control hydraulic pressure generation chamber 17, and the control hydraulic pressure generation chamber 17 Since the hydraulic pressure of P is released, the hydraulic pressure P
w will be given by the following equation.

Pw=(K/Sc) ・I...(1) That is, oil pressure P
w is proportional to the current I supplied to the linear solenoid 11, and the hydraulic pressure Pw of the control hydraulic pressure generation chamber 17 can be arbitrarily controlled by the current supplied to the linear solenoid 11. Braking oil pressure corresponding to the oil pressure Pw can be applied to the brake oil pressure chamber 4 of the brake device BFL.

By the way, both coils 63a, 6 of the linear solenoid 11
The current supplied to the coils 3b is controlled by a control circuit 64, and the control circuit 64 supplies half of the current amount to both coils 63 in accordance with the amount of braking operation obtained by the load cell 39.
a, 63b on duty, and when either one of both coils 63a, 63b fails, the entire amount of current corresponding to the amount of braking operation is applied on duty and both coils 63 are applied.
A and 63b are configured to be switchable between the states in which the voltage is applied to the other one.

That is, the control circuit 64 includes a current setting circuit 65 for setting the electric current if to be applied to both coils 63a and 63b according to a signal from load cell 39, and both coils 63a and 63b.
An oscillation circuit 66 that inputs an oscillation signal for fault diagnosis to the current setting circuit 65, a 1/2 current setting circuit 67 that sets the current to half of the current set by the current setting circuit 65, and a duty setting current amount. a duty setting circuit 6 days, the current setting circuit 65 and the l/2 current setting circuit 67.
and a pair of transistors 70a and 70b whose base terminals are connected in parallel to the duty conversion circuit 68 and whose emitter terminals are connected in parallel to the power supply 71. , transistor 70a.

Switches 72a and 72b are respectively interposed between the collector terminal of 70b and coils 63a and 63b, fault diagnosis circuits 73a and 73b are used to diagnose faults in both coils 63a and 63b, and switching modes of switch 69 are changed. The re-failure diagnosis circuits 73a and 73b
and an OR circuit 74 connected to.

As shown in FIG. 4(a), the oscillation circuit 866 outputs pulses with a time width T2 at intervals of, for example, 1 second, and the time width T2 does not affect the operation of the linear solenoid 11. It is set to a short time, for example, about 1 m5ec. Further, the current setting circuit 65 superimposes an oscillation signal from the oscillation circuit 66 on a set current corresponding to a signal indicating the amount of braking operation from the load cell 39 and outputs the resultant current. The output from the setting circuit 65 is as shown in ) in FIG. 1 more,
/ 2 The set current is reset to 1/2 based on the input signals from the current stage setting circuit 67 and the current setting circuit 65, and the setting current of the 1/2 current setting circuit 67 is reset when the braking operation is not performed. The output is as shown in FIG. 4(C).

The switch 69 has an individual contact 69a connected to the current setting circuit 65, an individual contact 69b connected to the 1/2 current setting circuit 67, and a common contact 69c connected to the duty conversion circuit 68. , the switching mode changes depending on the output of the OR circuit 74. That is, the OR circuit 74 outputs a high level signal when either the coils 63a or 63b is malfunctioning.
When the output of the OR circuit 74 is low level, the switch 69 conducts the individual contacts 69b to the common contact 69c, and when the output of the OR circuit 74 becomes high level, the switch 69 connects the individual contacts 69a to the common contact 69c. The switching mode is switched to conduction to the contact 69c.

The duty setting circuit 68 outputs a duty signal corresponding to the set current signal inputted through the switch 69, and when the output of the OR circuit 74 is at a low level when no braking operation is performed, that is, when both coil 6
When both 3a and 63b are normal, the output of the duty conversion circuit 68 becomes as shown in FIG. 4 (dl).

Transistors 70a and 70b are turned on and off in response to the output signal of this demi-ty other circuit 68, and both coils 63a are turned on and off.

A current as shown in FIG. 4(e) flows through each of the terminals 63b. This current is not enough to operate the linear solenoid 11, but is used for fault diagnosis.

The fault diagnosis circuits 73a and 73b are connected between the switch 72a and the coil 63a, and between the switch 72b and the coil 63b, respectively, and are normal when the current shown in FIG. 4(e) is flowing during non-braking operation. It determines this and outputs a low-level signal, and when any other current flows, it determines that there is a failure and outputs a high-level signal. In other words, when both coils 63a, 63b are disconnected or short-circuited, or in the event of a failure such that transistors 7Qa, 70b remain conductive or disconnected, the signals input to the fault diagnosis circuits 73a, 73b are at a low level. or remain at a high level,
It is thereby possible to diagnose a malfunction.

The switches 72a and 72b are connected to the corresponding fault diagnosis circuit 73a.
, 73b becomes high level. Therefore, when the failure diagnosis circuit 13a determines that there is a failure and outputs a signal of level Z4, the switch 72a shuts off, and the failure diagnosis circuit 73b determines that there is a failure and outputs a signal of high level. Sometimes the switch 72b shuts off.

Both fault diagnosis circuits 73a and 7 are connected to the input terminals of the OR circuit 74.
3b is input, so the OR circuit 74
When the output of either of the fault diagnosis circuits 73a, 73b becomes high level, that is, both coils 63a
.

Next, the operation of this embodiment will be described. First, assume that the brake pedal 32 is depressed to perform a braking operation while the hydraulic pressure supply source S is operating normally and the linear solenoid 11 is also operating normally. At this time, in the auxiliary hydraulic pressure supply means 33, the hydraulic pressure from the hydraulic pressure supply source S is acting on the hydraulic pressure source hydraulic chamber 49, so in the switching valve section 35, the spool valve body 44 moves to the left in FIG. , the reaction chamber 40 communicates with the achiemulator A2 via a communication hole 47, a spring chamber 48, an oil passage 58, an annular groove 52, an annular recess 54, and a boat 59. Therefore, accumulator A! The user depresses the brake pedal 32 to perform a braking operation while receiving a reaction force from the brake pedal 32, thereby providing a feeling of braking operation.

Moreover, the reaction chamber 40 responds to the depression of the brake pedal 32.
The hydraulic pressure increases, and the load cell 39 increases in accordance with the increase in hydraulic pressure.
output will also increase. In other words, the load cell 39 outputs a signal corresponding to the amount of braking operation, and in response to the signal from the load cell 39, the control circuit 64 outputs a signal corresponding to the amount of braking operation.
Excitation currents each half of the set current corresponding to the braking operation amount are applied to 3a and 63b. As a result, the linear solenoid 11 exerts a thrust corresponding to the amount of braking operation, and the hydraulic pressure corresponding to the thrust, that is, the oil pressure corresponding to the amount of braking operation, is generated in the control oil pressure generation chamber 17 of the modulator IFL. Hydraulic pressure in the generation chamber 17 causes the free piston 2
By acting on the back of the brake 0, a brake hydraulic pressure corresponding to the brake operation amount is generated in the brake hydraulic chamber 4 of the brake device BFL.

In this way, the brake hydraulic pressure corresponding to the brake operation amount can be applied to the brake hydraulic pressure chamber 4 of the brake device BFL.

By the way, during braking operation, spool 1 of modulator 1□
0 is one that moves at high speed in the axial direction, and the spool 10
There is a possibility that air may be generated due to cavitation in the control oil pressure generation chamber 17 when the control oil pressure is moved rightward in FIG. 1 at high speed. Although it is necessary to prevent air from entering the brake hydraulic chamber 4 of the brake device Byt, a free piston 20 is interposed between the brake hydraulic pressure generating chamber 17 and the brake hydraulic chamber 4, and the free piston 20 is regulated by the partition wall 14, it is possible to reliably prevent air generated in the control oil pressure generation chamber 17 from entering the brake oil pressure chamber 4 due to cavitation. Moreover, since the control oil pressure generation chamber 17 is located in the circulation path between the oil pressure supply '1IJS and the oil tank T, the air generated in the control oil pressure generation chamber 17 is discharged to the oil tank T.

When the oil pressure from the oil pressure supply source S decreases due to a failure in the oil pressure supply 1s, it becomes difficult to generate oil pressure in the control oil pressure generation chamber 17 of the modulator LFL. However, the auxiliary hydraulic pressure supply means 3
3, as the oil pressure in the oil pressure source oil pressure chamber 49 decreases, the spool valve body 44 in the switching valve portion 35 moves rightward in FIG. It communicates with the auxiliary input boat 31 via the annular recess 57, the annular groove 53, the annular recess 56, and the auxiliary output port 1. Moreover, since the free piston 20 retreats to its retraction limit in response to a decrease in the oil pressure in the control oil pressure generating chamber 17, the auxiliary input boat 31 communicates with the output chamber 21. Therefore, the brake oil pressure corresponding to the depression of the brake pedal 32 acts directly on the brake oil pressure chamber 4, and the brake oil pressure can be reliably obtained even if the oil pressure supply R8 is out of order.

Moreover, when the hydraulic pressure supply source S fails, the boat 59 connected to the achievator A2 is cut off from the reaction chamber 40 by the right movement of the spool valve body 44 in the switching valve section 35 of the auxiliary hydraulic pressure supply means 33, and therefore the brake pedal 32 is cut off from the reaction chamber 40.
The occurrence of invalid strokes can be avoided.

A pair of coils 63a, 6 in the linear solenoid 11
3b becomes malfunctioning, that is, when a disconnection or short circuit occurs, or when one of the transistors 7Qa, 7
Let's assume that 0b goes out of order. In this case, when the failure is detected by the failure diagnosis circuits 73a and 73b,
Both coils 63a.

The current application to the malfunctioning one of 63b is stopped,
The entire set current corresponding to the braking operation amount is applied to the remaining normal one. Thereby, the linear solenoid 11 can exert a thrust corresponding to the amount of braking operation, and both coils 63a.

63b is malfunctioning, the brake hydraulic pressure corresponding to the amount of braking operation is applied to the brake hydraulic pressure chamber 4 of the brake device BFL.
can be made to act.

In the above embodiment, the braking oil pressure is generated only by the signal from the load cell 39, but an anti-lock control signal and a truck movement control signal are added to the braking operation amount signal obtained from the load cell 39 to generate a linear solenoid. 1
1, it is also possible to control the braking oil pressure.

C1 Effects of the Invention As described above, according to the present invention, an electromagnetic solenoid that exerts a thrust according to the amount of input electricity is interlocked and connected to the end thereof, and a control hydraulic pressure generating chamber that exerts a hydraulic pressure to counter the thrust is provided. The spool is formed such that the spool faces the other end surface and is movable in the axial direction between a hydraulic pressure supply position where the hydraulic pressure supply source is communicated with the control hydraulic pressure generation chamber and a hydraulic pressure release position where the hydraulic pressure in the control hydraulic pressure generation chamber is released. A free piston is slidably fitted into the first cylinder body and has a back pressure chamber communicating with the control oil pressure generation chamber and an output chamber communicating with the brake device on both end faces, and is slidably fitted into the second cylinder body, Since the second cylinder body is provided with a stopper that restricts the retracting limit position of the free piston toward the back pressure chamber side, it is possible to obtain braking oil pressure according to the amount of electricity supplied to the magnetic solenoid, and the configuration is simple. In addition, the hydraulic pressure generated in the control hydraulic pressure generating chamber acts on the brake device via the free piston, so that the hydraulic pressure generated in the controlled hydraulic pressure generating chamber is controlled according to the axial movement of the spool. It is possible to reliably prevent the generated air from entering the brake device.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a hydraulic control circuit diagram, and FIG. 2 is a hydraulic control circuit diagram. Fig. 3 is a characteristic diagram of the electromagnetic solenoid, and Fig. 4 is a timing chart showing the signals in each part of the control circuit when both coils are normal in a non-braking operation state. 1 cylinder body, 5b
...Second cylinder body, lO...Spool, 11...
・Glue near solenoid as an electromagnetic solenoid, 14...
- Bulkhead as a stopper, 17... control oil pressure generation chamber,
20...Free piston, 21...Output chamber, 22.
... Back pressure chamber, 23... Return spring, 31... Boat, B FL+ B Flll+ B ILI B mm
・”Brake device, S--Hydraulic supply source

Claims (2)

[Claims] (1) An electromagnetic solenoid that exerts a thrust according to the amount of input electricity is interlocked and connected to one end of the spool, and a control hydraulic pressure generating chamber that exerts a hydraulic pressure to counter the thrust faces the other end of the spool. , is slidably fitted to the first cylinder body so as to be freely movable in the axial direction between a hydraulic pressure supply position where the hydraulic pressure supply source is communicated with the control hydraulic pressure generation chamber and a hydraulic pressure release position where the hydraulic pressure of the control hydraulic pressure generation chamber is released. , a free piston whose both end faces face a back pressure chamber communicating with a control oil pressure generation chamber and an output chamber communicating with a brake device is slidably fitted into the second cylinder body, and the back pressure of the free piston is fitted into the second cylinder body. A braking hydraulic control device characterized by being provided with a stopper for regulating the limit position of retraction toward the room. (2) The brake hydraulic control device according to item (1), wherein the output chamber houses a return spring that urges the free piston toward the back pressure chamber.