JPH0616848Y2 - Deceleration sensing type braking hydraulic pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a deceleration sensing type braking hydraulic pressure control device.

[Prior Art] Conventionally, in a vehicle such as an automobile, a braking fluid pressure of a rear wheel, which is installed in the middle of a fluid pressure circuit connecting a master cylinder and a rear wheel brake and is generated by fluid pressure supplied from the master cylinder. As a braking fluid pressure control device for controlling the so-called deceleration sensing type, which senses a change in the vehicle load as a change in the vehicle deceleration during braking and controls the braking fluid pressure ratio of the rear wheels to the front wheels. A braking hydraulic pressure control device is known, and a sensor for sensing vehicle deceleration is
Several structures have been proposed, such as one using a ball-shaped inertial sensor or one using a sleeve-shaped inertial sensor.

For example, in Japanese Patent Application Laid-Open No. 61-175155, a deceleration-sensing braking hydraulic pressure control device using a sleeve-shaped inertial sensor is proposed in order to solve various problems caused by using a ball as the inertial sensor. Has been done.

Also, when the pressure difference between the inlet side and the outlet side increases due to the action of the spring that is installed in the pressure circuit and urges the valve element toward the valve seat, the inlet side and the outlet side will not change until the pressure difference reaches the set value. A metering valve is well known, which has a characteristic that the pressure on the outlet side is kept constant by shutting off the valve side and the pressure on the outlet side is kept constant, and when the pressure difference exceeds the set value, the inlet side and the outlet side are communicated with each other to increase the outlet side pressure. Is.

By the way, in the braking operation of the vehicle, in order to make the braking force generated on the front and rear wheels most ideal, it is necessary to change the hydraulic pressure supplied to the front and rear wheel brakes in accordance with the braking ability that the front and rear wheels can exert. Therefore, it is necessary to ideally distribute the braking force to be applied to each of the front and rear wheel brakes. An ideal hydraulic pressure curve representing this ideal distribution of the braking force is determined for each loading load of the vehicle, and they are constant for each vehicle. In order to prevent an early rear lock, which is a particular problem during braking, the braking hydraulic pressure ratio of the front and rear wheel brakes is controlled so that the braking hydraulic pressure supplied to the rear wheel brakes does not exceed the ideal hydraulic pressure curve. There is a need.

As is generally well known, the vehicle load shared by each of the front and rear wheels moves from the rear wheel side to the front wheel side during braking. Therefore, the braking ability of the rear wheels is reduced as compared to the front wheels, and the ideal hydraulic pressure curve is normally O in FIG.
It becomes a parabolic curve as indicated by the -A curve. The movement of the vehicle load from the rear wheel side to the front wheel side at the time of braking increases as the distance between the front and rear wheel axes becomes shorter, the vehicle center of gravity becomes higher, and the vehicle generated deceleration becomes larger. Therefore, in the case of a certain type of vehicle, for example, a one-box vehicle in which the height of the center of gravity of the vehicle is high in spite of the distance between the front and rear wheels, the degree of decrease in the braking ability of the rear wheels becomes large, and the ideal hydraulic pressure curve becomes It becomes lower as shown by the OB curve in FIG.

For this reason, in the above vehicle, in order to prevent the rear lock by lowering the braking hydraulic pressure for the rear wheel brakes below the ideal hydraulic pressure curve, the load weight only for the driver (hereinafter, this is In the above), it is necessary to set the braking fluid pressure that causes the movement start deceleration of the inertial sensor in the vehicle to be lower. That is, it is necessary to set a low break point (light product break point) in the hydraulic curve during light product.

[Problems to be solved by the invention] However, as shown in FIG. 6, the lower the light product folding point is, the OC line showing the vehicle-generated deceleration characteristic at the time of loading and the specified maximum loading weight (Hereinafter, this is referred to as a stacking time)
The distance W from the O-D line, which represents the vehicle-generated deceleration characteristic, becomes narrower. In addition, the vehicle braking force has a slight variation due to differences in the temperature of the brake lining, the initial braking speed, and the like, so the vehicle-generated deceleration characteristic curve in each loading state also has a variation.

Therefore, the lower the setting value of the light weight break point, the more difficult it becomes to reliably detect light weight and heavy weight.Especially, during light weight and medium weight, and between middle weight and heavy weight, erroneous There was a problem in that there was a possibility of operation.

[Object of the Invention] The present invention has been made in view of the above problems, and is provided with a control means for disconnecting the master cylinder and the rear wheel brake cylinder until the input hydraulic pressure exceeds a set value when the input hydraulic pressure rises. As a result, the rear lock can be reliably avoided, and even in a low hydraulic pressure region, the loading condition can be reliably sensed to appropriately control the braking hydraulic pressure ratio of the rear wheels to the front wheels, thereby enabling a deceleration sensing type braking hydraulic pressure control device. It is intended to provide.

[Means for Solving the Problems] Therefore, according to the present invention, a main body having a hydraulic pressure inlet communicating with the master cylinder and a hydraulic pressure outlet communicating with the rear wheel brake cylinder and a chamber provided in the main body are provided. A plunger housed so as to be movable back and forth in the vehicle front-rear direction, an inertial sensor that is arranged rearwardly of the plunger so as to be movable back and forth, and moves forward by deceleration of the vehicle, and biases the inertial sensor rearward, When the sensor spring that controls the movement start deceleration of the inertia sensor due to the change in the urging force and the input hydraulic pressure from the master cylinder exceed a predetermined value that causes the movement start deceleration of the inertia sensor in the vehicle, the input hydraulic pressure A deceleration-sensing type braking hydraulic pressure control device having a depressurizing means for depressurizing and transmitting the pressure to the rear wheel brakes. A valve seat and a valve body, and an urging means for urging the valve body in the valve seat direction, and provided with a valve mechanism that maintains a closed state until the pressure difference between the front and rear reaches a set value, When the input fluid pressure rises,
The master cylinder and the rear wheel brake cylinder are shut off until the input hydraulic pressure exceeds the set value.

[Advantage of the Invention] According to the present invention, when the input hydraulic pressure rises to the hydraulic pressure inlet side or the hydraulic pressure outlet side of the deceleration-sensing type braking hydraulic pressure control device, the master is maintained until the input hydraulic pressure exceeds the set value. Since a valve mechanism that disconnects the cylinder and the rear wheel brake cylinder is provided,
It is possible to increase the input hydraulic pressure corresponding to the light product break point,
Therefore, the movement start deceleration of the inertial sensor during light load becomes large, and the difference between the input hydraulic pressure at the time of heavy load and mid load and the difference between the input hydraulic pressure at mid load and light load against this deceleration are Can be large. As a result, the light load rear lock area is reliably avoided, stable running is maintained during braking operation, and the loading situation is reliably detected even in the low hydraulic pressure area near the light load break point, resulting in variations in braking force. In contrast, stable hydraulic characteristics can be obtained, and safe drivability during vehicle braking can be maintained.

Further, according to the present invention, by controlling the hydraulic pressure characteristics of the control means, it is possible to provide a braking hydraulic pressure control device having various different hydraulic pressure characteristics. It has the advantage of.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a cover 2 is integrally connected to a rear portion of a body 1 through a seal ring 3,
The body 1 is formed with a plunger fitting hole 4 in the vehicle front-rear direction.

A front end of the plunger fitting hole 4 is closed by a plug 5, and a rear end of the plunger fitting hole 4 extends into the cover 2 by a cylindrical portion 1a protruding from a rear surface of the body 1.

A first chamber 7 is provided in the front part of the plunger fitting hole 4, and a first chamber 7 is defined in the middle part by seal rings 12, 12 of a plunger 11 fitted in the plunger fitting hole 4 so as to be movable back and forth. Two chambers 8 are provided, and a third chamber 9 including a hollow portion in the cover 2 is provided at the rear part, and the seal ring 12 and the seal cup 25 are provided between the second chamber 8 and the third chamber 9. An air chamber 10 partitioned by is provided.

A hydraulic pressure inlet portion 14 communicating with a master cylinder (not shown) is provided on a side portion (see FIG. 2) of the body 1, and a first branch leading from the hydraulic pressure inlet portion 14 to the second chamber 8 is provided. Passage 15
And a second branch passage 16 reaching the third chamber 9 is formed.

Further, a hydraulic pressure outlet 17 communicating with a rear wheel cylinder (not shown) is provided in the upper portion of the body 1, and the third branch passage 18 and the third chamber 9 from the hydraulic pressure outlet 17 to the first chamber 7 are provided.
And a fourth branch passage 19 is formed.

The fourth branch passage 19 opens at the rear surface of the body 1, and the seat 20 is fitted into the opening.

The plunger 11 is biased forward by a main spring 13 that is compressed in the air chamber 10.

The plunger 11 has a large-diameter pressure receiving surface portion 11 inside the second chamber 8.
a is formed, and a small diameter pressure receiving surface portion 11b is formed in the third chamber 9.

Further, the plunger 11 is formed with an internal passage 21 that communicates the first chamber 7 and the second chamber 8, and a front portion of the internal passage 21 is urged forward by a spring 22 so that the valve seat 23 is closed. A poppet valve 24 that closes the internal passage 21 when seated is provided, and the poppet valve 24 moves backward from the valve seat 23 as the plunger 11 moves forward and the tip 24a abuts the front wall 7a of the first chamber 7. The inner passage 21 is designed to open when the seat is separated.

On the other hand, a sleeve-shaped inertial sensor 26 is fitted in the third chamber 9 via the ball bearings 31, ...

The inertia sensor 26 is compacted between a spring holder 28 that is stopped by a seal retainer 27 that is fitted into the inner diameter (stepped portion) of the tubular portion 1a and a spring seat 29 that closes the rear end of the inertia sensor 26. Sensor spring 3
The rear end portion 26a is urged rearward by 0 and the third chamber 9
It is in contact with the rear wall 9a.

A rear end portion 26a of the inertia sensor 26 has a rear wall 9a of the third chamber 9.
The while abutting, a gap t ₁ has not been formed between the seat 20 of the front end portion 26b and the fourth branch passage 19 of the inertial sensor 26, an inertial sensor 26 is moved by _a minute gap t forward At this time, the inertial sensor 26 closes the fourth branch passage 19.

In the plunger 11, a shoulder portion 11c that separates the gap t ₂ is provided between the wall 7b after the first chamber 7, the shoulder 11 that separates a clearance t ₃ between the spring holder 28 of the third chamber 9
d is provided and the gap t ₂ > t ₃ is set, and when the plunger 11 moves rearward by the gap t ₃ , the plunger 11 compresses the sensor spring 30 via the spring holder 28. There is.

By the way, the braking hydraulic pressure control device according to the present embodiment maintains the valve closed state at the hydraulic pressure inlet portion until the input hydraulic pressure reaches a predetermined set value, and opens when the input hydraulic pressure exceeds the above set value. A metering valve 50 having a valve characteristic is incorporated.

The metering valve 50 will be described below.

As shown in FIG. 2, a casing 51 having a communication hole 51a in the center is liquid-tightly fitted in the cavity of the body 1 forming the fluid pressure inlet, and a valve is provided on the inlet side of the casing 51. The seat body 52 is fluid-tightly fitted to the side wall of the fluid pressure inlet 14. On the inlet side of the valve seat body 52, an inlet plug 57 having a hydraulic pressure inlet 59 communicating with a master cylinder (not shown) is attached to the packing 5
It is screwed to the body 1 via 8.

In the center portion of the valve seat body 52, a ball storage portion 56 for storing the ball valve 53, and a seat hole 5 for communicating the ball storage portion 56 with the hydraulic pressure inlet 59.
2a is provided, and the ball storage portion 5 of the seat hole 52a is provided.
A valve seat portion to be combined with the ball valve 53 is provided at the opening to 6. The ball valve 53 accommodated in the ball accommodating portion 56 so as to be vertically movable is biased toward the valve seat side (downward in the drawing) by a plate-shaped leaf spring 54. In addition to the seat hole 52a, the valve seat body 52 has at least one communication passage 52b for communicating the inlet side and the outlet side of the valve seat body 52.
Provided on the inlet side of the communication passage 52b.
A reed valve 55 that opens and closes b is mounted so as to be vertically movable.

When the input hydraulic pressure acts on the metering valve having the above structure, first, the communication passage 52b is closed by the reed valve 55, and the leaf spring 54 is attached until the input hydraulic pressure reaches the set value. The ball valve 53 is pressed against the valve seat by the force, and the seat hole 52a is also closed. Therefore, in this state, the input hydraulic pressure is not transmitted to the output side, and the output hydraulic pressure is 0. Then, when the input hydraulic pressure is increased and exceeds the set value, the urging force of the leaf spring 54 is overcome, the ball valve 53 is separated from the valve seat, and the seat hole 52a is opened. At this point, the input side and the output side are communicated with each other for the first time, and thereafter, the downstream pressure of the metering valve 50 is increased as the input hydraulic pressure rises.

The operation of the braking hydraulic pressure control device having the metering valve 50 built in the hydraulic pressure inlet will be described with reference to the graph of FIG. 4 showing the change in hydraulic pressure.

While the input hydraulic pressure Pi is between 0 and the valve-opening set pressure Pm of the metering valve 50, the input side and the output side are shut off, so the output hydraulic pressure Po is maintained at 0. Input hydraulic pressure Pi
When exceeds the set pressure Pm, the normal deceleration sensing type braking hydraulic pressure control device is operated.

That is, the plunger 11 is moved forward by the main spring 13 from the input hydraulic pressure Pi to the vicinity of the break point Pke at the time of light loading (state of FIG. 1), and the tip end portion 24 a is moved to the front wall of the first chamber 7. 7a, the poppet valve 24 retracts,
Separated from the valve seat 23, the internal passage 21 of the plunger 11 is opened.

Therefore, the hydraulic pressure Pi of the master cylinder is changed from the hydraulic pressure inlet portion 14 to the first branch passage 15 → the second chamber 8 → the internal passage 21 →
First chamber 7 → third branch passage 18 → first hydraulic pressure outlet 17
From the flow path a and the hydraulic pressure inlet portion 14 to the second branch passage 16 → the third
It acts on the rear wheel cylinder through the chamber 9 → the fourth branch passage 19 → the second flow path b reaching the hydraulic pressure outlet 17.

In the case of light load, when the inertial sensor 26 moves forward due to the deceleration of the biasing force G ₁ of the sensor spring 30 or more due to the hydraulic pressure near the break point Pke during light load, the front end portion 2 of the inertial sensor 26
Since the fourth branch passage 19 is closed by 6b, the second flow passage b is closed and only the first flow passage a is formed.

Then, the plunger 11 moves back and forth within the range of the clearance t ₄ (see FIG. 1) to act as a proportional pressure reducing valve (PCV).

In the case of medium and heavy products, at the hydraulic pressure near the break point Pke during light product,
Since the deceleration exceeding the urging force (G ₁ ) of the sensor spring 30 does not occur, the second flow path b remains open.
When exceeding the break point Pke during light loading, the second flow path b remains open, and the plunger 11 causes the main spring 1 to move due to the working fluid acting on the large diameter pressure receiving surface portion 11a of the plunger 11.
3 is moved backward against the urging force of the sensor spring 30.
And at the same time the poppet valve 24 moves forward and seats on the valve seat 23,
Will come to close.

Therefore, the hydraulic pressure Pi of the master cylinder is equal to the second flow path b.
To act on the rear wheel cylinder.

Next, the deceleration more than the urging force (G ₂ ) of the compressed sensor spring 30 is generated by the hydraulic pressure near the break point Pke at the time of middle loading or the break point Pkf at the time of heavy loading, and the inertial sensor 26 moves forward. When it moves, the fourth branch passage 19 is closed by the front end portion 26b of the inertia sensor 26, so that the second flow path b is also closed.

As described above, according to the present embodiment, at the hydraulic pressure inlet portion of the braking hydraulic pressure control device, the metering valve that shuts off the input side and the output side until the input hydraulic pressure Pi exceeds the set value Pm. Since 50 is provided, the input hydraulic pressure Pke corresponding to the light product break point Pke can be increased. Therefore, the movement start deceleration G ₁ of the inertial sensor 26 at the time of light product is increased, and the deceleration is supported. Input hydraulic pressure P during stacking and intermediate stacking
It is possible to increase the difference in i and the difference in the input hydraulic pressure Pi between the medium product and the light product. As a result, the light load rear lock area is surely avoided, stable running is maintained during the braking operation, and the loading condition is reliably sensed even in the low hydraulic pressure area near the light load break point Pke, so that the braking force is increased. It is possible to obtain stable hydraulic pressure characteristics against variations and to maintain safe drivability during vehicle braking.

Further, according to the present invention, it is possible to provide a braking hydraulic pressure control device having various different hydraulic pressure characteristics by controlling the hydraulic pressure characteristics of the metering valve, so that the applicable vehicle types can be expanded. You can

That is, in the above embodiment, the input hydraulic pressure Pi is set to the set value Pm.
Meter valve 50 having a characteristic that, after opening the valve to shut off the input side and the output side, the output hydraulic pressure Pi is increased at an increasing rate equal to the increasing rate of the input hydraulic pressure Po until it reaches Therefore, not only the light product break point Pke but also the heavy product break point Pkf are designed to move in a direction in which the input hydraulic pressure Pi increases by Pm. When a metering valve is used that has a characteristic that the output hydraulic pressure is increased at an increase rate that is larger than the input hydraulic pressure increase rate until the pressure reaches a predetermined value, the stacking point is changed. It is possible to change only the light-weight folding point without changing.

The second embodiment of the present invention will be described below.

In the following description, the same parts as those in the first embodiment are designated by the same reference numerals and further description will be omitted.

As shown in FIG. 3, the hydraulic pressure inlet 14 and the second branch passage 1
A metering plunger 62 is inserted into a cavity 61 provided between the metering plunger 62 and the No. 6 so that the metering plunger 62 can move back and forth. An O-ring 63 is attached to the outer peripheral portion of the front part of the metering plunger 62. It is supported by a plug 64 fixed to the body 1 by a ring 65. In front of the plug 64, a cap 66 that closes the cavity 61 is fixed to the body.

Spring holder 6 that abuts the rear end of the plug 64
7 and the collar portion 62a of the metering plunger 62, a set spring 68 for urging the metering plunger 62 rearward (input side) is contracted, and the input side end surface of the collar portion 62a has a body A ring valve 71 is mounted between the valve seat 69 and the valve seat 69 formed on the first step.
In the rear portion of the metering plunger 62, a ball storage portion 73 for storing the ball valve 72, and a seat for connecting the ball storage portion 73 and the second branch passage 16 through the communication passage 62b and the cavity 61. A hole 62c is provided, and a valve seat portion to be combined with the ball valve 72 is provided at the opening of the seat hole 62c to the ball storage portion 73. The ball valve 72 accommodated in the ball accommodating portion 73 so as to be movable back and forth is biased forward (valve seat side) by a valve spring 74.

In front of the metering plunger 62, a cap 66, an O-ring 63, and a metering plunger 6 are provided.
The atmosphere chamber 76 defined by the seal ring 75 mounted on the outer peripheral part of
A gap is formed between the front end face of the plug 64 and the guide portion end face 64a of the plug 64 in a state in which the braking hydraulic pressure does not act.

In the metering valve 60 having the above structure, the ring valve 71 is urged by the urging force of the set spring 68 and the valve spring 74 when the input hydraulic pressure is not applied.
Both the ball valve 72 and the ball valve 72 are closed. Even if the input hydraulic pressure acts, the valves 71 and 72 are kept closed and the output hydraulic pressure remains 0 until the input hydraulic pressure reaches the set value. Then, when the input hydraulic pressure is increased and exceeds the set value, the urging force of the set spring 68 is overcome, the ring valve 71 starts to separate from the valve seat 69, and the output hydraulic pressure starts to rise. When the input hydraulic pressure is further increased, the metering plunger 62 contacts the guide portion end surface 64a of the plug 64, the gap between the ring valve 71 and the valve seat 69 is secured, and the input hydraulic pressure and the output hydraulic pressure are equal. Become.

FIG. 5 is a graph showing changes in hydraulic pressure of the braking hydraulic pressure control device according to the second embodiment. As can be seen from this figure, in the present embodiment, the input hydraulic pressure Pi is the metering valve 60. Of the output hydraulic pressure Po is higher than the increase rate of the input hydraulic pressure Pi until the pressure is increased over the valve opening set pressure Pm ₁ and reaches the second set value Pm ₂ which is lower than the stacking break point Pkf. The pressure is increased at a high rate of increase, and the input hydraulic pressure Pi is the second set value P.
When m ₂ is exceeded, the input hydraulic pressure Pi and the output hydraulic pressure Po become equal. Therefore, it is possible to change only the light product break point Pke ′ without changing the heavy product break point Pkf.

As described above, according to the present invention, for vehicle models having different required hydraulic characteristics, by selecting the hydraulic characteristics of the metering valve in accordance with the respective requirements, it is possible to meet the respective requirements. Thus, it is possible to provide a braking hydraulic pressure control device having excellent hydraulic pressure characteristics.

In each of the above embodiments, the metering valve was incorporated on the input side, but the same purpose can be achieved by incorporating it on the output side.

Further, in any of the above embodiments, the metering valve was built in the braking fluid pressure control device, but the metering valve is configured as a valve independent of the above device, and the inlet side of the braking fluid pressure control device or Needless to say, the same effect can be obtained even if the outlet side is connected in series.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a deceleration sensing type braking hydraulic pressure control device according to a first embodiment of the present invention, FIG. 2 is a plan sectional view of a metering valve in the first embodiment, and FIG. FIG. 4 is a plan sectional view of a metering valve according to an embodiment, FIG. 4 and FIG. 5 are graphs showing hydraulic characteristics of a deceleration sensing type braking hydraulic pressure control device according to the first embodiment and the second embodiment, respectively. FIG. 6 is a graph showing the hydraulic pressure characteristic of the conventional deceleration sensing type hydraulic pressure control device. 1 ... Main body, 4 ... Plunger fitting hole, 7 ... First chamber, 11 ...
Plunger, 14 ... Liquid pressure inlet, 17 ... Liquid pressure outlet, 23 ...
Valve seat, 24 ... Poppet valve, 26 ... Inertial sensor, 30 ... Sensor spring, 50, 60 ... Metering valve.

Claims (1)

[Scope of utility model registration request] 1. A main body having a hydraulic pressure inlet communicating with a master cylinder and a hydraulic pressure outlet communicating with a rear wheel brake cylinder, and a chamber provided in the main body so as to be movable back and forth in a vehicle longitudinal direction. A plunger, an inertial sensor that is arranged behind the plunger so as to be movable back and forth, and moves forward by the deceleration of the vehicle, and the inertial sensor is biased rearward, and the inertial sensor starts to move due to a change in the biasing force. When the sensor spring for controlling the deceleration and the input hydraulic pressure from the master cylinder exceed a predetermined value that causes the vehicle to have a movement start deceleration of the inertial sensor, the input hydraulic pressure is reduced and the pressure reducing means is transmitted to the rear wheel brake. In a deceleration-sensing type braking hydraulic pressure control device including a valve seat and a valve body and the valve body in the valve seat direction on the hydraulic pressure inlet side or the hydraulic pressure outlet side of the braking hydraulic pressure control device. A urging means for urging is provided, and a valve mechanism that maintains a closed state until the pressure difference between the front and rear reaches a set value is provided.
A deceleration-sensing braking hydraulic pressure control device, characterized in that the master cylinder and the rear wheel brake cylinder are cut off until the input hydraulic pressure exceeds the set value.