JPS59277Y2 - Braking hydraulic control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a brake hydraulic control device installed in a vehicle, in particular,
a stepped inner hole having an inlet communicating with the master cylinder and an outlet communicating with the wheel cylinder, and having inside thereof a small diameter inner hole communicating with the inlet and a large diameter inner hole communicating with the outlet; A housing main body including a first oil chamber provided in parallel with the stepped inner hole and communicating with the small diameter inner hole and the large diameter inner hole, and a first oil chamber provided in the large diameter inner hole of the stepped inner hole. The diameter portion is slidably inserted to form a second oil chamber communicating with the first oil chamber, and the small diameter portion is slidably inserted into the small diameter inner hole of the stepped inner hole to form the first oil chamber. a differential piston forming a third oil chamber communicating with the oil chamber; a spring biasing the differential piston toward the second oil chamber; The present invention relates to an improvement in a brake hydraulic control device including a cutoff valve having an inertial valve body that cuts off communication between a first oil chamber and a second oil chamber.

Conventionally, in this type of device, during a sudden brake operation, the oil pressure applied to the second oil chamber before the shutoff valve closes is as follows (A) compared to a normal brake operation:
Due to the cause of B), the differential piston is pushed toward the third oil chamber by more than the necessary amount compared to when the brake is operated normally, and the desired braking oil pressure control function cannot be obtained. be.

(A) Since the sprung member of the vehicle to which the brake hydraulic control device is installed moves forward relative to the unsprung member during sudden braking, the sprung member must have sufficient inertia to move the valve body. The time when the force acts is delayed from the time when the inertial force acts on the unsprung member.

(B) During a sudden braking operation, the oil pressure applied to the first oil chamber rapidly increases, and while the inertial valve body is moving, this oil pressure passes through the shutoff valve and is applied to the second oil chamber. Ru.

The present invention focuses on the above-mentioned problems, and has been developed to solve the problem that, especially during sudden braking, the hydraulic pressure applied to the second oil chamber due to the causes (A) and (B) above becomes higher than that during normal braking. By suppressing the pressing force of the hydraulic pressure acting on the differential piston, it is attempted to prevent the differential piston from moving more than the required amount, and an example of this will be explained below with reference to the drawings. .

In FIG. 1, reference numeral 10 indicates a known tandem type master cylinder operated by the depression of a brake pedal 13, reference numeral 14 indicates a rear wheel cylinder, and reference numeral 15 indicates a front system oil chamber 1 of the master cylinder 10.
1 shows a front wheel cylinder that is directly connected by a conduit 16, and a brake hydraulic pressure control device 20 according to the present invention is interposed in a rear system pipe that connects the rear oil chamber 12 of the master cylinder 10 and the rear wheel cylinder 14. equipped.

The brake hydraulic control device 20 includes a housing body 30 fixed at a predetermined angle of inclination to a sprung member of the vehicle (not shown).
and a large diameter piston 41 incorporated into this housing body 30. It is equipped with a small diameter piston 42 and an inertia ball 46.

The housing body 30 includes a rear housing 30A having an inlet 31 connected to the rear oil chamber 12 of the master cylinder 10 by a conduit 17, and a front housing 30B having an outlet 32 connected to the rear wheel cylinder 14 by a conduit 18. It consists of an inlet port 3 inside it.
The stepped inner hole 33 has a small diameter inner hole 33a in which the outlet port 1 is opened, a large diameter inner hole 33b in which the outlet port 32 is opened, and an inner hole 33C in which the coil spring 43 is accommodated;
A first oil chamber R1 is provided in parallel with the stepped inner hole 33, which communicates with the small diameter inner hole 33a of 33 through a communication passage 35 and communicates with the large diameter inner hole 33b through a second communication passage 36.

In addition, inside this housing main body 30, there is an air vent passage that opens into the earthen wall of the first oil chamber R1 at one end, opens into the second communication passage 36 at the other end, and is normally closed by a plug 34. 37 are provided.

The large diameter piston 41 constitutes a differential piston together with the small diameter piston 42, and the large diameter inner hole 33 of the stepped inner hole 33
b through a seal member so as to be slidable in the axial direction, and the outflow port 32 opens directly into the large-diameter inner hole 33b, and the first oil chamber R1 communicates through the second communication path 36. A communicating second oil chamber R2 is formed.

Also, the left end of this large diameter piston 41 has a large diameter inner hole 33b.
An annular partition wall portion 41a having a smaller diameter is integrally formed, and the outer circumference of the partition wall portion 41a and the inner wall of the large diameter inner hole 33b form two oil chambers Ra,
An annular throttle passage S that communicates both oil chambers divided into Rb
is formed.

The small diameter piston 42 is a stepped piston, and the stepped inner hole 3
It is fitted into the small-diameter inner hole 33a of No. 3 so as to be slidable in the axial direction via a seal member, and the inlet 31 opens directly into the small-diameter inner hole 33a, and the first oil chamber R1 serves as a communication path. 3
A third oil chamber R3 is formed which communicates through the oil chamber R3.

Further, this small diameter piston 42 is in contact with the right end of the large diameter piston 41 at its left small diameter portion.

The compression coil spring 43 is assembled into the inner hole 33C with a predetermined preload applied thereto, and the right stepped portion of the large diameter piston 41 is connected to the left end of the compression coil spring 43 via an annular retainer 44 having a required outer diameter. The right end thereof is engaged with the rear housing 30A.

The inertia ball 46 is accommodated in the first oil chamber R1 so as to be able to move forward, and is connected to the first oil chamber R1 by an annular valve seat 45 interposed between the first oil chamber R1 and the second communication passage 36. It constitutes a cutoff valve that opens and closes communication between the second communication passages 36.

The inertia ball 46 is supported by a support plate 47 having an orifice 47a fixed to the rear housing 30A side, and when the inertia force (deceleration) acting thereon exceeds a predetermined value, it rolls forward. and seats on the valve seat 45.

In this embodiment configured in this way, during normal brake pedal operation, the hydraulic pressure generated in the front oil chamber 11 of the master cylinder 10 is applied directly to the front wheel cylinder 15 through the conduit 16, and the hydraulic pressure is applied to the rear oil chamber 15 directly through the conduit 16. Hydraulic pressure in 12 is applied through conduit 17 to inlet 31 of controller 20 .

Master cylinder oil pressure Pm applied to this inlet 31
is provided in the second oil chamber R2 through the third oil chamber R3 continuous passage 35 - the valve hole of the first oil chamber R1 valve seat 45 - the second communication passage 36 , and further passes through the outlet 32 and the conduit 18 to the rear wheel cylinder 14 granted to.

When master cylinder oil pressure is applied to each wheel cylinder 14, 15 in this manner, the vehicle is braked in accordance with the oil pressure Pm.

During this braking, the small diameter piston 42 is pushed to the left by the hydraulic pressure Pm applied in the third oil chamber R3, and the large diameter screws 1 to 41 are pushed to the right by the hydraulic pressure Pm applied in the second oil chamber R2. The large diameter piston 41 and the small diameter piston 42 slide to the right against the elastic force of the spring 43 due to the difference in their respective pressure receiving areas.

Note that at this time, since the oil pressure in the second oil chamber R2 rises relatively slowly, there is almost no differential pressure between the two oil chambers Ra and Rb partitioned by the partition wall 41a, and the large diameter piston 41 Their movement is not restricted.

When the master cylinder oil pressure Pm becomes Pl and the deceleration acting on the inertia ball 46 reaches a predetermined value, the ball 46 rolls forward and seats on the valve seat 45, and the first oil chamber R
Communication between the first and second communication paths 36 is cut off.

(See point A in Fig. 2) Therefore, when the master cylinder oil pressure Pm increases and the oil pressure in the third oil chamber R3 increases, both pistons 41 and 42 are pushed to the left, and the second oil chamber R
The oil pressure in 2 (rear wheel cylinder oil pressure Pw) is
It rises like line AB in the figure.

Thus, when master cylinder oil pressure Pm becomes P2,
The large-diameter piston 41 abuts against the left-end inner wall of the large-diameter inner hole 33b.

Therefore, even if the master cylinder oil pressure increases thereafter, the oil pressure in the second oil chamber R2 does not increase, and the oil pressure in the second oil chamber R2 does not increase.
It becomes constant like line C.

By the way, when the brake pedal 13 is depressed rapidly (during a sudden braking operation), the oil pressure in the second oil chamber R2 rises more rapidly than during a normal brake operation, so the pressure inside the second oil chamber R2 is divided by the partition wall 41a. Two oil chambers Ra, Rb
A transient pressure difference occurs between them.

Therefore, pressure oil flows from the oil chamber Rb into the oil chamber Ra through the annular throttle passage S, and the pressure loss caused by this inflow suppresses a rapid increase in the oil pressure in the oil chamber Ra.

As a result, the pressing force acting on the large-diameter piston 41 is approximately the same as that during normal brake operation, and abnormal movement of the large-diameter piston 41 to the right (movement beyond the required amount) is restricted.

Further, at this time, the ball 46 seats on the valve seat 45 while the movement of the large-diameter piston 41 is restricted, and after this seating, both pistons 46 sit before the oil pressure in the oil chamber Ra increases.
1.42 is pressed by the oil pressure in the third oil chamber R3.

As a result, hydraulic pressure is applied to each wheel cylinder 14, 15 at the distribution ratio shown by the broken line in FIG.

Note that point a in FIG. 2 shows when the ball 46 is seated on the valve seat 45 during sudden braking, and point b shows when the large diameter piston 41 comes into contact with the left end of large diameter inner hole 33b during sudden braking. It shows.

In addition, the broken line shown by the dashed line in Fig. 2 shows the distribution ratio obtained when sudden braking is performed by a device that does not implement the present invention, and the curve shown by the broken line shown by the dashed double dot in Fig. 2 is the ideal distribution ratio. It shows the allocation ratio.

In the above embodiment, the outer periphery of the partition wall 41a and the inner wall of the large-diameter inner hole 33b form an annular throttle passage that communicates the two oil chambers Ra and Rb divided by the partition wall 41a. S is formed to suppress the pressing force acting on the large-diameter piston 41 by the throttle passage S during sudden braking, and to restrict abnormal movement of the large-diameter piston 41 to the right. If the two oil chambers divided into two oil chambers Ra and Rb by a are made to communicate through an orifice, the desired action and effect can be achieved in a distant manner. Diameter inner hole 33
It is also possible to form an orifice with a groove provided along the axial direction in the partition wall portion 41a, or to form an axial orifice in the partition wall portion 41a itself.

Further, in the above embodiment, an example was explained in which a differential piston consisting of a large diameter piston 41 and a small diameter piston 42 was adopted as the differential piston, but an integrated stepped piston may also be adopted as the differential piston. It is possible.

In summary, in the present invention, a partition is provided in the large diameter portion of the differential piston to partition the second oil chamber into two oil chambers, and these two divided oil chambers are communicated through an orifice. This feature makes it possible to apply braking oil pressure close to the ideal distribution ratio to each wheel cylinder even during sudden braking operations.

[Brief explanation of the drawing]

Fig. 1 is a brake system diagram including a brake hydraulic control device according to the present invention, and Fig. 2 shows a brake hydraulic distribution ratio and an ideal distribution ratio curve obtained by a device according to the present invention and a device not implementing the present invention. It is a graph. Explanation of symbols, 10...Tandem type master cylinder,
14... Rear wheel cylinder, 2o... Braking hydraulic control device, 30... Housing body, 31... Inflow port, 32... Outlet port, 33... Stepped inner hole, 33
a...Small diameter inner hole, 33 b...Large diameter inner hole, 41...
・Large diameter piston, 41 a...Partition wall part, 42...Small diameter piston, 43...Spring, 46...Inertia ball (valve body), R1...First oil chamber, R2... Second oil chamber, R3...Third oil chamber, Ra, Rb...Oil chamber partitioned by a partition wall, S...A throttle passage (orifice).

Claims (1)

[Scope of utility model registration request] a stepped inner hole having an inlet communicating with the master cylinder and an outlet communicating with the wheel cylinder, and having inside thereof a small diameter inner hole communicating with the inlet and a large diameter inner hole communicating with the outlet; A nozzing body including a first oil chamber provided in parallel with the stepped inner hole and communicating with the small diameter inner hole and the large diameter inner hole; A second oil chamber whose large diameter portion is slidably inserted into the second oil chamber and communicates with the first oil chamber.
a differential piston that defines an oil chamber and whose small diameter portion is slidably inserted into the small diameter inner hole of the stepped inner hole to form a third oil chamber communicating with the first oil chamber; moving the moving piston to the second
The oil chamber includes a spring that biases toward the oil chamber, and a shutoff valve that is housed in the first oil chamber and has an inertial valve body that blocks communication between the first oil chamber and the second oil chamber by its inertial force. A braking hydraulic control device comprising: a partition wall portion protruding toward the outer circumference of the large diameter portion of the differential piston to partition the second oil chamber into two oil chambers; A braking hydraulic control device characterized by communicating through an orifice.