JPH0143338Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a brake fluid pressure control device for a vehicle equipped with a vehicle height adjustment mechanism.

In recent years, a vehicle height adjustment mechanism has been installed between a sprung member and an unsprung member of a vehicle, and the supply and discharge of pressurized fluid to the fluid pressure chamber of the vehicle height adjustment mechanism is controlled according to increases and decreases in vehicle load. 2. Description of the Related Art Vehicles whose vehicle height is maintained at a predetermined height have become popular. In addition, as a vehicle brake fluid pressure control device, the housing of the fluid pressure control valve that is interposed in the fluid pressure line between the master cylinder and the wheel cylinder and controls the fluid pressure applied to the wheel cylinder is attached to the sprung member of the vehicle. The valve body of the hydraulic pressure control valve is connected to an unsprung member of the vehicle, and the biasing force of a spring assembled to the valve body is adjusted in accordance with the relative displacement between the sprung member and the unsprung member. Vehicle load responsive brake fluid pressure control devices have also become popular.

By the way, this type of brake fluid pressure control device described above adjusts the biasing force of a spring attached to the valve body of a fluid pressure control valve in accordance with the relative displacement between the sprung member and the unsprung member of the vehicle. Therefore, for vehicles equipped with a vehicle height adjustment mechanism, in which the vehicle height is always maintained at a predetermined height regardless of increases or decreases in vehicle height load, it is necessary to Since there is no relative displacement, it will not function as a vehicle load response type.

The present invention was developed based on the above-mentioned circumstances, and its main purpose is to fix either a cylinder or a piston slidably fitted inside the cylinder to a sprung member, and to fix the cylinder to a sprung member. Alternatively, a spring is interposed between either one of the pistons and an unsprung member of the vehicle, and the vehicle height is controlled to a predetermined height by controlling the supply and discharge of pressure fluid to the cylinder according to increases and decreases in vehicle load. The present invention focuses on a vehicle equipped with a vehicle height adjustment mechanism that maintains the height of the vehicle, and provides a vehicle load responsive brake fluid pressure control device suitable for the vehicle.

Therefore, in order to achieve the above object, the present invention provides a vehicle equipped with the above-mentioned vehicle height adjustment mechanism, in which the hydraulic pressure applied to the wheel cylinder is controlled by intervening in the hydraulic pressure conduit between the master cylinder and the wheel cylinder. attaching a housing of a hydraulic pressure control valve to be controlled to a movable member of the cylinder or piston;
and a spring whose one end is attached to the unsprung member is connected directly or indirectly to the valve element of the hydraulic pressure control valve, so that the biasing force of the spring assembled to the valve element is applied to the movable side with respect to the unsprung member. This feature is characterized in that the adjustment is made according to the displacement of the member.

Hereinafter, the present invention will be explained based on the drawings. FIG. 1 shows a part of a vehicle with a vehicle height adjustment mechanism equipped with a brake fluid pressure control device according to a first embodiment of the present invention. This vehicle height adjustment mechanism is conventionally known, and includes a rear suspension 10a and a hydraulic control mechanism 1.
0b. The rear suspension 10a includes a fixed piston 11 fixed to a part of the vehicle body, which is a sprung member _A1 of the vehicle, and a movable cylinder 12 into which the fixed piston 11 is slidably inserted to form a hydraulic chamber R therein. , a compression spring 14 interposed between the movable cylinder 12 and a swinging arm 13 attached to a part of the vehicle body so as to be swingable in the vertical direction.
It is composed of: The fixed piston 11 has a cylindrical shape with a bottom, and supplies pressure oil from the hydraulic pump 15 constituting the hydraulic control mechanism 10b into the hydraulic chamber R through the hydraulic control device 16.
The pressure oil inside is discharged through the hydraulic control device 16. A top support 12a for locking the compression spring 14 is formed at the lower end of the movable cylinder 12, and a lower support 13a is formed at an intermediate portion between the top support 12a and the swing arm 13.
A compression spring 14 is interposed between the two.
As a result, the compression spring 14 elastically receives the movable cylinder 12 and increases or decreases the amount of deflection in response to an increase or decrease in the vehicle load. Note that the swing arm 13
An axle that is part of the unsprung member _A2 to which the rear wheel is attached is supported at the rear end of the rear end. on the other hand,
A hydraulic control mechanism 10 is located in the middle of the swing arm 13.
Lever portion 17a of vehicle height sensor 17 constituting b.
One end of the is attached. This vehicle height sensor 1
7 is a sprung member that occurs depending on the increase or decrease in vehicle load.
The relative displacement between A ₁ and the unsprung member A ₂ is detected, and the detection signal is provided to the electric control device 18 . Thereby, the electric control device 18 controls the hydraulic control device 16 according to the detection signal from the vehicle height sensor 17, and the hydraulic control device 16 controls the supply and discharge of pressure oil from the hydraulic pump 15 into the hydraulic chamber R. to maintain the vehicle height at a predetermined height. For example, if the amount of deflection of the compression spring 14 increases due to an increase in the vehicle load and the rear of the vehicle sinks, a predetermined amount of pressure oil from the hydraulic pump 15 is supplied into the hydraulic chamber R, thereby causing the fixed piston 11 relatively slides upward, and the vehicle height is adjusted to a predetermined height. Furthermore, after the vehicle height has been adjusted in this way, if the amount of deflection of the compression spring 14 becomes smaller due to a decrease in the vehicle load and the rear of the vehicle becomes higher, a predetermined amount of the pressure oil in the hydraulic chamber R is discharged. As a result, the fixed piston 11 relatively slides downward, and the vehicle height is adjusted to a predetermined height. Therefore, in this vehicle, when the vehicle load increases or decreases, the sprung member
A predetermined distance is maintained between A ₁ and unsprung member A ₂ ,
Moreover, the movable cylinder 12 is displaced with respect to the unsprung member _A2 according to an increase or decrease in the vehicle load.

Next, the brake fluid pressure control device 20, which is the main part of the present invention, will be explained. The brake fluid pressure control device 20 includes a fluid pressure control valve 20a and a tension spring 20.
It is composed of b.

The hydraulic pressure control valve 20a is a known valve that is interposed in a hydraulic line between the master cylinder and the rear wheel cylinder to control the hydraulic pressure applied to the rear wheel cylinder, and is connected to the valve housing 21 as shown in FIG. , a rod-shaped valve body 22 and a compression spring 2
3 is the main component. The valve housing 21 has a first port 21a connected to the master cylinder and a second port 21a connected to the rear wheel cylinder.
Port 21b and both ports 21a, 21
The inner hole 21c is provided with an inner hole 21c that communicates with the inner hole 21c.
A valve body 22 is slidably inserted therein, and its lower end protrudes downward. The valve body 22 is urged upward in the figure by the elastic force of the compression spring 23, and is separated from the valve seat 21d provided in the inner hole 21c, thereby communicating between the ports 21a and 21b. As a result, in the hydraulic pressure control valve 20a, when hydraulic pressure is generated in the master cylinder by pressing the brake pedal, this hydraulic pressure is applied to the rear wheel cylinder through both ports 21a and 21b, and the master cylinder hydraulic pressure reaches the set pressure. When the valve body 22 reaches this point, it starts operating, slides against the compression spring 23, and seats on the valve seat 21d, cutting off communication between the ports 21a and 21b. If the master cylinder oil pressure further increases, the valve body 22 moves up and down, repeatedly seating and separating from the valve seat 21d, controlling the increase in the oil pressure applied to the rear wheel cylinder, and adjusting the braking characteristics of the rear wheel. Get closer to the ideal curve.

Therefore, in this embodiment, the hydraulic pressure control valve 2
A valve housing 21 0a is attached to the outer periphery of a movable cylinder 12 constituting a rear suspension 10a of the vehicle height adjustment mechanism, and the lower end of the valve body 22 protrudes toward the unsprung member _A2 .
In addition, this unsprung member A ₂ has a tension spring 2
The lower end of 0b is locked, and its upper end is the valve body 2.
It is locked at the lower end of 2. The tensile force of the tension spring 20b is set to be smaller than the biasing force of the compression spring 23, and acts on the valve body 22 so as to reduce the biasing force of the compression spring 23.

Brake fluid pressure control device 20 configured in this way
, a valve housing 21 of a hydraulic pressure control valve 20a is attached to a movable cylinder 12 that is displaced with respect to an unsprung member _A2 according to an increase or decrease in vehicle load, and a compression spring 23 of the hydraulic pressure control valve 20a
Since the tension spring 20b that acts to reduce the biasing force of is locked to the unsprung member _A2 ,
The urging force acting on the valve body 22 can be adjusted according to the displacement of the movable cylinder 12. For example, when the vehicle load increases, the movable cylinder 1
2 is displaced downward, and at the same time, the valve housing 21 of the hydraulic control valve 20a is also displaced downward. Therefore, the tensile force of the tension spring 20b decreases as the displacement of the movable cylinder 12 increases, that is, as the vehicle load increases, and the biasing force applied to the valve body 22 increases as the vehicle load increases. As a result,
The hydraulic pressure at which the valve body 22 starts operating increases as the vehicle load increases. Additionally, when the vehicle load decreases, the movable cylinder 12 reduces its downward displacement, and at the same time, the downward displacement of the valve housing 21 also decreases. Therefore, the tensile force of the tension spring 20b increases as the displacement of the movable cylinder 12 decreases, that is, as the vehicle load decreases, and the biasing force applied to the valve body 22 decreases as the vehicle load decreases. As a result, the hydraulic pressure at which the valve body 22 starts operating becomes lower as the vehicle load decreases. Therefore, the brake fluid pressure control device 20 according to this embodiment can perform vehicle load responsive brake fluid pressure control in a vehicle equipped with the vehicle height adjustment mechanisms 10a, 10b.

FIG. 3 shows a part of a vehicle with a vehicle height adjustment mechanism equipped with a brake fluid pressure control device according to a second embodiment of the present invention. This vehicle height adjustment mechanism is composed of a rear suspension 10a and a hydraulic control mechanism 10b, as in the first embodiment. A valve housing 31 of a component hydraulic control valve 30a is attached. The hydraulic pressure control valve 30a functions in exactly the same way as the hydraulic pressure control valve 20a of the first embodiment, and as shown in FIG. A moving arm 34 is attached. Further, the valve body 32 is assembled into the inner hole 31c while being urged upward by the compression spring 33, and is spaced apart from the valve seat 31d. It is in contact with the middle part of. On the other hand, the upper end of the tension spring 30b is engaged with the tip of the push arm 34, and the lower end thereof is engaged with the unsprung member _A2 . The tensile force of the tension spring 30b is set to be smaller than the biasing force of the compression spring 33, and acts via the push arm 34 to reduce the biasing force of the compression spring 33.

Therefore, also in the brake fluid pressure control device 30 configured in this way, the biasing force acting on the valve body 32 can be adjusted according to the displacement of the movable cylinder 12, and as in the first embodiment, Vehicle load-responsive brake fluid pressure control can be performed in a vehicle equipped with the vehicle height adjustment mechanisms 10a and 10b.

In each of the above embodiments, a coil spring was used as the compression spring 14 of the rear suspension 10a constituting the vehicle height adjustment mechanism, but in the present invention, a plate spring, a plate spring, An example has been described in which a torsion spring or the like can be used, and a hydraulic control mechanism 10b is provided as a vehicle height adjustment mechanism to automatically adjust the vehicle height using hydraulic pressure. It is possible to adopt a vehicle height adjustment mechanism that allows the vehicle height to be adjusted automatically or manually. Furthermore, in each of the above embodiments, an example has been described in which the piston 11 constituting the rear suspension 10a is fixed to the sprung member _A1 and the cylinder 12 is used as a movable (displacement) member. cylinder 12
may be fixed to the sprung member _A1 , and the piston 11 may be used as a movable (displacement) member. In addition, in the present invention, the hydraulic pressure control valves 20a and 30a constituting each brake hydraulic pressure control device 20 and 30 are also used as a proportioning valve, a load sensing valve, etc., and are used as a master cylinder and a wheel cylinder. It is possible to employ various types of hydraulic pressure control valves that are interposed in the hydraulic conduit between the wheel cylinder and the wheel cylinder to control the hydraulic pressure applied to the wheel cylinder.

As explained above, according to the present invention, the valve body of the hydraulic pressure control valve is adjusted according to the displacement of the movable side member of the cylinder or piston that constitutes the vehicle height adjustment mechanism, which is displaced in response to an increase or decrease in the vehicle load. Since the biasing force of the assembled spring can be adjusted, the hydraulic pressure at which the valve body starts operating can be adjusted according to increases and decreases in vehicle load. Responsive brake fluid pressure control can be performed.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view of a main part of a vehicle showing a first embodiment of the present invention, Fig. 2 is an enlarged longitudinal sectional view of a hydraulic pressure control valve adopted in the same embodiment, and Fig. 3 is a longitudinal sectional view of a hydraulic control valve adopted in the same embodiment. 2
FIG. 4 is an enlarged longitudinal sectional view of a hydraulic pressure control valve employed in the embodiment. Explanation of codes, 10a...Rear suspension,
10b...Hydraulic control mechanism, 11...Fixed piston, 12...Movable cylinder, 13...Swing arm, 14...Compression spring, 20, 30...Brake fluid pressure control device, 20a, 30a...Hydraulic pressure Control valve, 20b, 30b... tension spring, 2
1, 31... Valve housing, 22, 32...
Valve body, 23, 33... Compression spring, 34...
Pushing arm, A ₁ ... sprung member, A ₂ ... unsprung member, R ... hydraulic chamber.

Claims (1)

[Scope of utility model registration request] Either a cylinder or a piston slidably fitted into the cylinder is fixed to a sprung member, and a spring is interposed between the other of the cylinder or piston and the unsprung member. In a vehicle equipped with a vehicle height adjustment mechanism that maintains the vehicle height at a predetermined height by controlling the supply and discharge of pressure fluid to the cylinder, there is a hydraulic pressure pipe in the master cylinder and the wheel cylinder. A housing of a hydraulic pressure control valve intervening to control the hydraulic pressure applied to the wheel cylinder is attached to the movable member of the cylinder or piston, and one end is attached to the valve body of the hydraulic pressure control valve under the spring. The spring attached to the member is directly or indirectly linked to adjust the biasing force of the spring attached to the valve body in accordance with the displacement of the movable member with respect to the unsprung member. brake fluid pressure control device.