JP2724753B2 - Hydraulic pressure control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic control device provided in a brake of a vehicle.

(Prior Art) Generally, in a vehicle such as an automobile, a load applied to a front wheel is larger than a load applied to a rear wheel because a heavy object such as an engine is disposed at a front portion. For this reason, the braking force on the front wheel side greatly contributes to the braking of the vehicle,
The braking force distribution is set to be large on the front wheel side and small on the rear wheel side. This braking force distribution is normally set by the brake cylinder diameter of a brake device such as a disc brake or a drum brake, a hydraulic control valve, and the like.

When the brake fluid pressure input from the master cylinder or the like reaches a certain pressure (cut point pressure), the fluid pressure control valve outputs fluid pressure at a rate smaller than the rate of increase of the inputted fluid pressure. There is a load-sensitive type (LSPV) in which the cut point pressure increases as the load on the vehicle increases. Since the hydraulic pressure of the adaptive load type pressure control valve increases as the load applied to the rear wheel increases, the hydraulic pressure at which locking of the rear wheel begins to increase increases. This makes it possible to more effectively use the braking force of the wheels. Note that the adaptive load type hydraulic pressure control valve detects the relative displacement between the rear wheel and the vehicle body, and controls based on the detected relative displacement.

On the other hand, some vehicles are provided with an anti-skid device for controlling braking fluid pressure of a brake system during sudden braking to prevent wheels from locking, thereby ensuring braking performance and steering stability. This anti-skid device is usually provided on the left and right brake systems on the front wheel side, and is separately provided on the left and right sides or commonly on the rear wheel side.

Then, by using the hydraulic control valve and the anti-skit device in combination for the brake, the braking performance can be more efficiently performed. In the braking force distribution, the braking force is set to be larger on the front wheel side, and the front wheel side is likely to be locked, so that the front wheel anti-skid device normally operates first.

(Problems to be Solved by the Invention) However, the control of the hydraulic pressure control valve is started when the brake hydraulic pressure reaches a certain cut point pressure, and the supply of the hydraulic pressure to the rear wheel side brake device is started. When the vehicle is loaded, the braking force on the rear wheel side is reduced, and when the anti-skid device on the front wheel is activated, even if the brake pedal is depressed strongly, the hydraulic pressure of the brake device on the rear wheel side is reduced. However, there is a problem that the braking force is largely insufficient due to a low rise rate of the vehicle.

In addition, the above-mentioned problem can be solved by the adaptive load type hydraulic control valve, but since the control is performed by detecting the relative displacement between the rear wheel and the vehicle body, the mounting position is restricted to a position where the relative displacement can be detected. There were problems such as complicated mounting work.

The present invention has been made in view of the above problems, and it is an object of the present invention to be able to more efficiently secure the braking force of the rear wheels without using a variable pressure type hydraulic pressure control valve. It is to provide a hydraulic control device.

(Means for Solving the Problems) A hydraulic pressure control device according to the present invention includes a front wheel brake system for connecting a brake hydraulic pressure source and a front wheel side brake device, and a brake hydraulic pressure source and a rear wheel side brake device. An anti-skid device is provided in each of the connected rear wheel brake systems, and the downstream pressure receiving area is larger than the upstream pressure receiving area in the system connecting the rear wheel brake system anti-skid device and the rear wheel side brake device. Hydraulic control means comprising a valve mechanism for connecting and disconnecting the rear wheel brake system in accordance with the movement of the piston due to the difference in pressure receiving area due to the increase in the piston and the brake hydraulic pressure; A cut that urges the piston in a direction to maintain communication with the rear wheel brake system by a pressure difference between a brake hydraulic pressure and an output hydraulic pressure of the anti-skid device of the front wheel brake system. And point pressure changing means.

(Operation) With the above configuration, before the anti-skid device is activated, the hydraulic pressure control unit increases the hydraulic pressure from the brake hydraulic pressure generation source to reach a predetermined pressure (cut point pressure). The valve mechanism repeats communication and disconnection of the rear wheel brake system according to the movement of the piston due to the difference in area, suppressing the rise rate of the brake fluid pressure supplied to the brake device to a low level, and distributing the braking force between the front wheel side and the rear wheel side Set to act as a normal hydraulic pressure control valve.

Then, when the anti-skid device of the front wheel brake system operates to reduce the brake fluid pressure of the front wheel brake system, the pressure difference between the brake fluid pressure of the front wheel brake system and the brake fluid pressure of the rear wheel brake system is reduced by the cut point pressure changing means. Since the piston of the hydraulic pressure control means is urged in a direction to maintain the communication of the brake system, the cut point pressure is changed to be high, and the braking force by the rear wheel brake device is maintained. Also, even if the cut point pressure is changed to be high and the rear wheel side is likely to lock,
The anti-skid device is activated to prevent locking.

In this way, even if the anti-skid device of the front wheel brake system operates due to sudden braking or the like, the cut point pressure of the hydraulic pressure control means is changed to be high, so that the braking force on the rear wheel side can be used effectively. It is possible to ensure the maximum braking force of the vehicle.

Next, a first embodiment of the present invention will be described with reference to FIG. In the present embodiment, the brake system is X-pipe, and one of the two outputs of the master cylinder, which is a brake fluid pressure source, is piped to the right front wheel brake device and the left rear wheel brake device. The other is connected to the left front wheel brake device and the right rear wheel brake device. Also, since these two pipes have the same configuration,
Only one system will be described.

Front wheel brake system 3 for connecting the output side of master cylinder 1 and front wheel side brake device 2 and master cylinder 1
The anti-skid devices 6 and 7 are disposed in a rear wheel brake system 5 that connects the output side of the vehicle and the rear wheel side brake device 4. The anti-skid devices 6 and 7 are general devices, and the control unit determines a state in which locking is likely to occur based on the number of rotations of the wheels and the like, and the switching valve is controlled based on the determination to control the brake fluid pressure. The braking force is controlled by reducing or increasing the pressure to prevent the wheels from being locked.

The system connecting the anti-skid device 7 of the rear wheel brake system 5 and the rear wheel brake device 4 includes a pressure control means 8.
And a cut point pressure changing means 9 are provided.

To explain these means 8, 9, a cylinder 15 composed of a small-diameter cylinder portion 11, a large-diameter cylinder portion 12, a small-diameter cylinder portion 13, and a medium-diameter cylinder portion 14 is formed in the main body 10 from the right side in the figure. The piston 16 is slidably provided on the cylinder 15. The piston 16 has a large-diameter cylinder
The two piston portions 17 and 18 are formed in sliding contact with the large-diameter cylinder portion 12 and the medium-diameter cylinder portion 14, respectively.
Is divided into two chambers 19 and 20 by a piston portion 17, and similarly, the medium-diameter cylinder portion 14 is divided into two chambers 21 and 2 by a piston portion 18.
It is divided into two. The chambers 19, 20, 21, 22 are sealed by O-rings 23.

A spring member 24 is provided in one chamber 19 of the large-diameter cylinder section 12, and biases the piston 16 in one direction (left direction in the figure).

In addition, the piston portion 18 that slides on the medium-diameter cylinder portion 14,
The pressure receiving area of the hydraulic pressure received from one chamber 21 on the upstream side is set smaller than the pressure receiving area of the hydraulic pressure received from the other chamber 22 on the downstream side. Furthermore, the middle cylinder part 14-2
The two chambers 21 and 22 are provided with communication passages 25 formed in the piston 16.
The communication passage 25 communicates within the communication passage 25.
A shutoff valve mechanism 26 is provided. This valve mechanism 26
Is a ball valve that can be seated on a valve seat 27 formed in the communication passage 25.
28, a spring member 29 for urging the ball valve 28 in the direction of the valve seat 27, and a rod 30 fixed to the main body 10 and inserted into the communication passage 25, when the piston 16 is urged in one direction. When the ball valve 28 is pushed by the rod 30 and the communication path 25 is communicated, and the piston 16 moves in the other direction (right direction in the drawing), the ball valve 28 is seated on the valve seat 27 and the communication path 25 is cut off. In addition, the piston 16 and the valve mechanism 26
The hydraulic pressure control means 8 is configured.

The output side of the anti-skid device 7 provided in the rear wheel brake system 5 is connected to a large-diameter cylinder 12 through a port 31.
The one chamber 19 is connected to one chamber 21 of the medium-diameter cylinder portion 14 by a passage 32 formed in the main body 10. Then, the other chamber 22 of the medium-diameter cylinder portion 14
Is connected to the rear wheel brake device 4 via the port 33.

The output side of the anti-skid device 6 of the front wheel brake system 3 is connected to the other chamber 20 of the large-diameter cylinder portion 12 via a port 34, and further from the other chamber 20 via a port 35 to the front wheel side brake device 2 Connected to. The large-diameter cylinder part 12, the piston part 17, and the chambers 19 and 20 constitute the cut point pressure changing means 9.

 The operation according to the above configuration will be described.

When hydraulic pressure is generated in the master cylinder 1 during braking, in the front wheel brake system 3, hydraulic pressure is supplied from the anti-skid device 6 to the front wheel side brake device 2 through the other chamber 20 of the large diameter cylinder portion 12, In the rear wheel brake system 5, one chamber 19 of the large-diameter cylinder portion 12, the passage 32, one chamber 21 of the medium-diameter cylinder portion 14, the communication passage 25, and the other chamber 22 of the medium-diameter cylinder portion 14
, The hydraulic pressure is supplied to the rear wheel side brake device 4 to generate a braking force. In this state, the magnitude of the brake fluid pressure is the same until each of the anti-skid devices 6 and 7 operates, and the fluid pressure in one chamber 19 of the large-diameter cylinder portion 12 and the fluid pressure in the other chamber 20 are large. Is the same as

When the brake fluid pressure rises and reaches a certain fluid pressure (cut point pressure), the piston 16 resists the biasing force of the spring member 24 in the other direction due to the difference in the pressure receiving area of the piston portion 18 of the medium diameter cylinder portion 14. And the valve mechanism 26 shuts off the communication passage 25. Further, when the communication passage 25 is shut off, the hydraulic pressure in the one chamber 21 of the medium-diameter cylinder portion 14 increases due to the hydraulic pressure from the master cylinder 1, and the piston portion 18 is again pushed in one direction, and the valve mechanism 26 The communication passage 25 is communicated. In this way, the piston 16 reciprocates in response to an increase in the brake fluid pressure on the master cylinder 1 side, and the valve mechanism 26 repeatedly communicates and shuts off the communication passage 25, thereby providing the fluid to be supplied to the rear wheel brake device 4. Keep the rate of pressure rise low. Thus, the braking force distribution between the front wheels and the rear wheels is set such that the front wheels are locked earlier than the rear wheels from the viewpoint of vehicle stability.

Next, the anti-skid device 6 arranged in the front wheel brake system 3 is operated by sudden braking or the like, and the brake fluid pressure supplied to the front wheel side is reduced, so that the fluid in the other chamber 20 of the large-diameter cylinder portion 12 is reduced. The pressure becomes lower than the hydraulic pressure in one chamber 19, and the differential pressure generated in piston portion 17 urges piston 16 in one direction. The rear wheel brake system 5
Piston due to the difference in pressure receiving area due to increase in brake fluid pressure
The movement of 16 is suppressed by the differential pressure, and the cut point pressure is changed to a higher value. Thereby, the braking force on the rear wheel side is maintained. At this time, the hydraulic pressure supplied to the rear wheel side brake device 4 rises, and the rear wheel side is in a state where locking is likely to occur. However, the lock is activated by the operation of the anti-skid device 7 of the rear wheel brake system 5. Is prevented.

Here, the cut point pressure is set appropriately in the piston portion 17 in sliding contact with the large-diameter cylinder portion 12, the pressure receiving area of the hydraulic pressure received from one chamber 19 and the pressure receiving area of the hydraulic pressure received from the other chamber 20, The value can be changed to an arbitrary value by adjusting the force for urging the piston 16 in one direction by the differential pressure.

In this manner, the cut point pressure is changed to a higher value by utilizing the differential pressure generated between the front wheel brake system 3 and the rear wheel brake system 5 by the operation of the anti-skid device 6 of the front wheel brake system 3, thereby more effectively. The braking force of the vehicle can be secured.

In the first embodiment, in the rear wheel brake system 5, the output side of the anti-skid device 7 and one chamber 19 of the large-diameter cylinder portion 12 are connected. As shown, the output side of the master cylinder 1 is directly connected to one chamber 19 of the large-diameter cylinder section 12, and the output side of the anti-skid device 7 is directly connected to one chamber 21 of the medium-diameter cylinder section 14. Is also good. In this case, the operation is the same.

Next, a second embodiment of the present invention will be described with reference to FIG.

A front wheel brake system 36 that connects the output of the master cylinder 1 as a brake fluid pressure source and the front wheel side brake device 2
And output of master cylinder 1 and rear wheel side brake device 4
As in the first embodiment, general anti-skid devices 38 and 39 are connected to the rear wheel brake system 37 that connects the two. In the drawing, the front wheel and the rear wheel are integrated, but separate control is performed on the front wheel side and the rear wheel side (38, 38 on the front wheel side). 3 on rear wheel side
9).

Next, the anti-skid device of the rear wheel brake system 37
The hydraulic pressure control means 40 and the cut point pressure changing means 41 arranged on the path connecting the rear wheel side brake device 4 to the brake 39 will be described.

In the main body 42, a hydraulic pressure control means 40 a cut point pressure changing means
41 are provided. First, the hydraulic pressure control means 40 will be described. In the main body 42, a control cylinder 45 composed of a large-diameter cylinder portion 43 and a small-diameter cylinder portion 44 is formed. Part 43 in two rooms 46,4
A control piston 49 having a piston section 48 partitioned into 7 is slidably provided. In addition, each room 46,47
Are sealed by O-rings 50,50.

A spring member 51 is provided in one chamber 46 of the large-diameter cylinder section 43, and urges the control piston 49 in one direction (rightward in the drawing).

In the piston portion 48, the pressure receiving area of the hydraulic pressure received from the one chamber 46 on the upstream side is set smaller than the pressure receiving area of the hydraulic pressure received from the other chamber 47 on the downstream side. Further, the two chambers 46 and 47 communicate with each other through a communication passage 52 formed in the control piston 49, and a valve mechanism 53 that can shut off the communication passage 52 is provided in the communication passage 52. The valve mechanism 53 includes a ball valve 55 that can be seated on a valve seat 54 formed in the communication passage 52, and a spring member 56 that biases the ball valve 55 in the valve seat 54 direction.
And a rod 57 fixed to the main body 42 and inserted into the communication passage 52. When the control piston 49 is urged in one direction, the rod 57 pushes the ball valve 55 to communicate the communication passage 52. When the control piston 49 moves in the other direction (left direction in the drawing), the ball valve 55 is seated on the valve seat 54 and the communication passage 52 is shut off. The output side of the anti-skid device 39 of the rear wheel brake system 37 is connected to one chamber 46 of the large-diameter cylinder portion 43 via a cut-point pressure changing means 41, which will be described in detail later. The chamber 47 is connected to the rear wheel brake device 4.

Next, the cut point pressure changing means 41 will be described. In the main body 42, a differential pressure detecting cylinder 61 including a central large-diameter cylinder portion 58 and small-diameter cylinder portions 59 and 60 on both sides is formed. The pressure detecting cylinder 61 is provided with a differential pressure detecting piston 65 having a piston portion 64 for partitioning a large-diameter cylinder portion 58 into two chambers 62 and 63 slidably. The chambers 62 and 63 are sealed by O-rings 66.

A spring member 67 is provided in one chamber 62 of the large-diameter cylinder portion 58, and urges the differential pressure detection piston 65 in one direction (to the right in the drawing). The other chamber 63 of the large-diameter cylinder part 58
Is connected to the output side of the anti-skid device 39 of the rear wheel brake system 37 via a port 68, and further connected to one chamber 46 of the control cylinder 45 via a passage 69.

The differential pressure detecting piston 65 is provided with a communication passage 71 that communicates the other chamber 63 of the large-diameter cylinder chamber 58 with the chamber 70 formed in the one small-diameter cylinder 60. A valve mechanism 72 having the same configuration as the valve mechanism 53 and communicating / blocking the communication path 71 is provided in the communication path 71. Since the configuration of the valve mechanism 72 is the same as that of the valve mechanism 53, the description is omitted. When the differential pressure detecting piston 65 is urged in one direction, the valve mechanism 72 closes the communication passage 71, and the differential pressure detecting piston 65 moves in the other direction (left direction in the figure). Then, the communication path 71 is in communication.

An adjusting cylinder 73 is formed on the small-diameter cylinder portion 44 side of the control cylinder 45, and an adjusting piston 76 that partitions the adjusting cylinder 73 into two chambers 74 and 75 is formed in the adjusting cylinder 73. It is slidably provided. The one chamber 74 is provided with a spring member 77 for urging the control piston 49 in one direction, and the other chamber 75 includes
The chamber 70 of the small-diameter cylinder section 60 of the differential pressure detecting cylinder 61
Are connected via a passage 78 formed in the main body 42. The passage 78 branches off in the middle, and is connected to the output side of the master cylinder 1 via a passage 79 and a pipe 80 formed in the main body 42. The passage 78 has a room 70
A check valve 81 is provided to allow only the flow of the oil liquid to the other chamber 75 of the adjusting cylinder 73, and the passage 79 has an output of the master cylinder 1 from the other chamber 75 of the adjusting cylinder 73. A check valve 82 is provided to allow the oil liquid to flow to the side.

The output side of the anti-skid device 38 of the front wheel brake system 36 is connected to one chamber 62 of the differential pressure detecting cylinder 61 via a port 83, and the port 83 branches on the way and branches to the rear wheel side brake device 2. And a passage 84.

 The operation according to the above configuration will be described.

When hydraulic pressure is generated in the master cylinder 1 during braking, in the front wheel brake system 36, hydraulic pressure is supplied from the anti-skid device 38 to the front wheel side brake device 2 through the port 83,
In the rear wheel brake system 37, from the anti-skid device 39, the other chamber 63 of the large-diameter cylinder portion 58 of the differential pressure detection cylinder 61,
Hydraulic pressure is supplied to the rear wheel-side brake device 4 through the passage 69, the one chamber 46 of the large-diameter cylinder portion 43 of the control cylinder 45, the communication passage 52, and the other chamber 47 to generate a braking force. .
In this state, the brake fluid pressure is the same until each of the anti-skid devices 38 and 39 operates, and the fluid pressure in one chamber 62 of the large-diameter cylinder portion 58 of the cylinder 61 for differential pressure detection and the other The hydraulic pressure in the chamber 63 is the same.

When the brake fluid pressure rises and reaches a certain fluid pressure (cut point pressure), the control piston 49 moves in the other direction against the urging force of the spring member 51 due to the difference in the pressure receiving area of the piston part 48,
The valve mechanism 53 shuts off the communication passage 52. Further, when the communication passage 52 is shut off, the hydraulic pressure in the one chamber 46 of the large-diameter cylinder portion 43 increases due to the hydraulic pressure from the master cylinder 1, and the piston portion 48 is pushed again to one side to communicate with the valve mechanism 53. The passage 52 is communicated. In this way, the control piston 49 reciprocates in response to the increase in the brake fluid pressure on the master cylinder 1 side, and the valve mechanism
The communication passage 52 is repeatedly communicated / blocked by the 53, so that the rising rate of the hydraulic pressure supplied to the rear wheel brake device 4 is suppressed to a low level. Thus, the braking force distribution between the front wheels and the rear wheels is set such that the front wheels are locked before the rear wheels from the viewpoint of vehicle stability.

Next, the anti-skid device 38 arranged in the front wheel brake system 36 is operated by sudden braking or the like, and the brake fluid pressure supplied to the front wheel side is reduced.
Hydraulic pressure in one chamber 62 of the large-diameter cylinder portion 58
And the pressure difference detecting piston 65 moves in the other direction against the urging force of the spring member 67, and the valve mechanism
The communication path 71 is communicated with the communication path 72. Therefore, the brake fluid pressure on the rear wheel side is introduced into the other chamber 75 of the adjusting cylinder 73, and moves the adjusting piston 76 in one direction. As a result, the spring member 77 presses and biases the control piston 49 in one direction, and the movement of the control piston 49 due to the difference in the pressure receiving area accompanying the increase in the brake fluid pressure of the rear wheel brake system 37 is prevented. The pressure is reduced by the urging force of the spring member 77, and the cut point pressure increases. At this time, the hydraulic pressure supplied to the rear wheel side brake device 4 rises and the rear wheel side is likely to be locked, but the lock is activated by the activation of the anti-skid device 39 of the rear wheel brake system 37. As a result, the braking force can be effectively maintained.

Here, the cut point pressure adjusts the force for urging the control piston 49 in one direction by appropriately setting the resilient force of the spring member 77 provided in the one chamber 74 of the adjusting cylinder 73. This can be changed to an arbitrary value.

In the second embodiment, the hydraulic pressure introduced into the other chamber 75 of the adjusting cylinder 73 is controlled by the anti-skid device 38,3.
Regardless of the operation of 9, the brake fluid pressure is maintained until the master cylinder 1 stops generating the brake fluid pressure.

(Effects of the Invention) As described in detail above, after the front wheel side anti-skid device is operated, the communication between the rear wheel brake system and the rear wheel brake system is performed by the pressure difference between the front wheel brake system and the rear wheel brake system. , The cut point pressure is increased by biasing the piston in a direction to maintain the braking force, and the braking force on the rear wheel side can be effectively used, so that the braking force of the vehicle can be improved.

Further, since it is not necessary to use a conventional adaptive pressure type hydraulic pressure control valve, the degree of freedom of setting such as mounting is expanded.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the hydraulic pressure control device of the present invention, FIG. 2 is a schematic diagram showing a modification of the first embodiment shown in FIG. 1, FIG. FIG. 4 is a schematic view showing a second embodiment of the hydraulic control device of the present invention. DESCRIPTION OF SYMBOLS 1 ... Master cylinder (brake fluid pressure generation source) 2 ... Front wheel side brake device 3 ... Front wheel brake system 4 ... Rear wheel side brake device 5 ... Rear wheel brake system 6, 7 ... Anti-skid device 8 ... ... Hydraulic pressure control means 9 ... Cut point pressure changing means 12 ... Large diameter cylinder part 16 ... Piston 17 ... Piston part 19,20 ... Chamber 26 ... Valve mechanism

Claims (1)

(57) [Claims] An anti-skid device is provided for each of a front wheel brake system for connecting a brake fluid pressure source and a front wheel side brake device and a rear wheel brake system for connecting the brake fluid pressure source to a rear wheel side brake device. In the system that connects the anti-skid device of the rear wheel brake system and the rear wheel side brake device, the pressure receiving area on the downstream side is larger than the pressure receiving area on the upstream side. Communication with the rear wheel brake system according to the movement of the piston due to the difference in pressure receiving area
A fluid pressure control means comprising a valve mechanism for shutting off; and a direction for maintaining communication with the rear wheel brake system by a differential pressure between a brake fluid pressure of the rear wheel brake system and an output fluid pressure of the anti-skid device of the front wheel brake system. And a cut point pressure changing means for urging the piston.