JPS5943158Y2 - G valve - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a G valve installed in a hydraulic control circuit in a vehicle brake system.

The control characteristics of a vehicle vary depending on the type of vehicle or the amount of load on the vehicle. For example, when there are large fluctuations in the load, the ideal brake oil pressure setting for the front and rear wheels may be activated when the load is low.
This is significantly different from that when the vehicle is heavily loaded, and it is known that in the former case the rear wheel braking force is significantly reduced, whereas in the latter case the reduction rate may be small.

In order to obtain heavy braking force for the front and rear wheels of the vehicle in accordance with such braking characteristics, for example, the brake oil pressure transmitted to the wheel cylinder of the rear wheel brake system is adjusted by the oil pressure increase rate from a predetermined oil pressure value (break point). Various types of proportioning valves are available, including a combination of a proportioning valve that changes the hydraulic pressure and gradually raises the hydraulic pressure, and a load response mechanism that further changes the hydraulic pressure turning point in accordance with the load capacity of the vehicle.

The present invention relates to G pulp, which has a relatively simple structure and is used for such hydraulic control.

This type of G pulp is produced by a ball valve that is interposed between a mask cylinder and a rear wheel side wheel cylinder, and that moves inertially in the forward direction of the vehicle in the valve chamber due to deceleration during vehicle braking, and comes into contact with the valve seat. This is used in a hydraulic control circuit that cuts hydraulic communication and, if necessary, slowly increases the brake hydraulic pressure in the rear wheel cylinder after the cut by operating a proportional control valve connected by bypass.

However, conventional G valves do not directly measure changes in the vehicle's load carrying capacity, but always cut hydraulic pressure at a constant deceleration, and indirectly measure changes in the load carrying capacity. By changing the correlation between brake oil pressure and deceleration, it is possible to obtain a certain degree of oil pressure cut when the load is high.

For this reason, in vehicle types such as freight cars that have large load fluctuations, there is a problem in that the deviation from the ideal brake force distribution that changes as described above becomes large.

Therefore, when the load is low, the brake oil pressure can be cut at a relatively low deceleration, and when the load is high, the brake oil pressure can be cut at a relatively high deceleration. At times of high loading when only a low brake force increase rate can be obtained, there is also a system that secures a brake force close to the ideal brake force on the rear wheel side without cutting the hydraulic pressure at a sufficiently high brake oil pressure value 1. For example, this was proposed in Japanese Patent Publication No. 44-5063.

However, since the proposed G-valve rotates the bushing that supports the ball within the circular cavity of the cylinder body, it has a large sliding area and requires strict machining accuracy to ensure smooth operation. There are also difficulties from this perspective.

The present invention has been made with the object of solving these difficulties and providing a G-pulp having a structure that is relatively simple and easy to assemble and ensures smooth operation.

The gist of the present invention, which has been made to achieve such an object, is that the ball valve in the valve chamber inertia moves approximately in the forward direction of the vehicle due to deceleration during vehicle braking and comes into contact with the valve seat. , a guide surface button that guides the inertial movement of the ball valve toward the valve seat and a valve seat to which the ball valve is abutted, for a G valve that cuts hydraulic communication between the mask cylinder and the rear wheel side wheel cylinder. A ball support base with By providing a spring that tilts the end of the support base opposite to the valve seat upward in the direction of decreasing the elevation angle of the guide surface, and sliding it approximately in proportion to the increase in the oil pressure of the mask cylinder, the valve of the ball support base A piston is installed whose end opposite to the seat is tilted downward in the direction of increasing the elevation angle against a spring force, and the vehicle deceleration required for the inertial movement of the ball valve to come into contact with the valve seat is masked. The G pulp is characterized in that it is configured to increase as the oil pressure of the cylinder increases.

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 shows a hydraulic control circuit including a vertical cross-sectional view of G Pulp, and 1 is a cylinder body, which includes a cylinder part 3 in which a piston 2 is slidably fitted in an axially slidable manner, and a pulp chamber 4. ing.

Reference numeral 5 designates a ball support stand (hereinafter referred to as the pedestal) which is disposed within the valve chamber 4 and has a U-shaped cross section with an upward opening, and the outside portion on the front side of the vehicle is rotatably attached to the cylinder body 1 through an arcuate connection portion 6. connected.

Reference numeral 7 denotes a valve seat provided on the inner side of the vehicle front side of the pedestal 5, and a flow path 8 opened to the valve seat 7 is communicated with a port 9 of the cylinder body 1 via the connecting portion 6, and the button is connected to the valve seat 7. port 9
is connected to a wheel cylinder 11 of a rear wheel brake device via a hydraulic path 10.

A connecting member 12 made of an elastic body is attached to the connecting portion 6 between the cylinder body 1 and the pedestal 5, and is sealed from the inside of the valve chamber 4 except for the opening at the valve seat 7.

A spring 13 is stretched between the inner wall of the pulp chamber 4 and the pedestal 5, and presses the pedestal 5 toward the front of the vehicle and also presses the rear portion of the pedestal 5 upward.

Reference numeral 14 denotes a guide surface forming the bottom surface of the recess of the pedestal 5, which guides the ball valve 15 housed in the recess toward the valve seat 7.

Further, the upper part of the pedestal 5 on the rear side of the vehicle abuts the small diameter portion 16 of the piston 2 protruding into the pulp chamber 4 as shown in the figure, and the piston 2 is prevented from moving upward by a stopper 17. It is held still at the position shown in the figure by the pressing force of the spring 13.

Therefore, the guide surface 14 that guides the ball valve 15 of the pedestal 5 forms an angle of elevation α with respect to the vehicle forward direction C2 shown by the arrow in the figure, and is moved downward against the pressing force of the spring 13 of the biston 2. The pedestal 5 is configured to swing around the connecting portion 6 and tilt at a maximum elevation angle α2 (α2>α, )1.

A flow path 18 is formed in the axial center of the piston 2, and communicates the inside of the pulp chamber 4 with a port 20 that communicates with a mask cylinder (not shown) via a hydraulic path 19.

21 is a proportional control valve, which is bypass-connected to the G pulp by a hydraulic line 22.23.

Next, the operation will be explained.

Since there is no deceleration before the vehicle is braked, the ball valve 15
is biased toward the lowest portion (vehicle rear side position) of the guide surface 14 that is inclined with respect to the vehicle forward direction.

When brake hydraulic pressure is generated in the mask cylinder during vehicle braking, the hydraulic pressure is transmitted from the port 20 to the valve chamber 4 via the flow path 18 of the piston 2, and further from the opening of the valve seat 7 to the flow path 8.
, and is transmitted to the rear wheel cylinder 11 via the port 9.

Therefore, the same oil pressure is generated not only on the front wheel side but also on the rear wheel side, and the braking force increases as the oil pressure increases.

This braking force brakes the vehicle and causes deceleration, but the value of the brake oil pressure P and the value of the deceleration change in correlation with the load capacity of the vehicle as described above, and the ball valve 15 The deceleration required to contact the valve seat 7 is gc
Then, the deceleration ge also changes in correlation with a change in the inclination angle α of the guide surface 14, that is, the pedestal 5 with respect to the vehicle forward direction (shown by line C1 in the figure).

From the above relationship, if the inclination angle of the guide surface 14 in the initial state of zero brake oil pressure is α1, and the inclination angle that increases as the brake oil pressure increases is αX, then gc = G (C
1 sin αx + c2 cos αX)…1°1 (however, G =
Weight acceleration, C0 = cos α1, C2 = sin α1) Also, if we ignore the displacement in the C0 line direction in the figure due to the tilting of the guide surface 14 (however, C3 = the elastic coefficient of the spring 13 and the value of the brake oil pressure) constant, C4=distance from the center of tilting to the end of tilting 1) Also, the pressing force of the spring 13 at the initial stage is ignored.

Because it is becomes.

gc shown in equation 3 has an inflection point P=a)0 (a: constant), and in the range a>P>0 it shows an upwardly convex curve, a)P=b)0 (b : constant) has a maximum value at point b, so by setting the constants C1 to C4 in accordance with the actual vehicle characteristics, the curve of deceleration gc shown in FIG. 2 can be obtained.

Therefore, as the load capacity of the vehicle changes from zero (empty) to maximum load (constant load), the actual deceleration g whose rate of increase is inversely proportional to the brake oil pressure, as shown in Figure 2. The structure is such that the brake hydraulic pressure is cut when the deceleration exceeds the deceleration gc, which increases as the brake hydraulic pressure increases (g>gc), and the brake hydraulic pressure is cut at a constant deceleration regardless of the conventional load capacity. Compared to the conventional G-pulp, the G-valve of the present invention can correct the hydraulic cut point in relation to the load carrying capacity, so even in the case of a vehicle with variable load, the ideal brake for the front and rear wheels can be maintained. The practical benefits are extremely significant, such as being able to obtain pre-braking characteristics that approximate force distribution, expanding the range of application, and improving safety during vehicle braking.

In addition, the G-valve according to the present invention has a simple structure, good assembly workability, and has excellent effects in that the guide surface can be tilted extremely smoothly.

The present invention is not limited to the embodiments described above, and can also control the brake hydraulic pressure in the same way as a so-called limiting valve, so that the hydraulic pressure is not cut when the load is high, such as when the load is broken. It is also possible to configure

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a brake hydraulic pressure control circuit diagram including a vertical cross-sectional view of the G valve, and FIG. 2 is a diagram showing a characteristic curve of deceleration gc required for hydraulic cut. 1... Valve body, 2... Piston, 3... Cylinder, 4... Valve chamber, 5... Pedestal, 6... ...Connection part, 7...
...Valve seat, 8...Flow path, 9...Port, 10...Hydraulic pressure path, 11...Rear wheel side wheel cylinder, 12・・・・・・Elastic body, 13・
...Spring, 14...Guide surface, 15...
... Ball valve, 16 ... Piston small diameter section,
17... Stopper, 18... Channel, 1
9...Hydraulic path, 20...Port, 2
1... Proportional control valve, 22.23... Hydraulic path.

Claims (1)

[Scope of utility model registration request] In the G valve of the type in which the ball valve in the valve chamber inertia moves substantially in the forward direction of the vehicle due to deceleration during vehicle braking and comes into contact with the valve seat, cutting off hydraulic communication between the mask cylinder and the rear wheel side wheel cylinder. A ball support base, which is equipped with a guide surface that guides the inertial movement of the ball valve toward the valve seat and a valve seat to which the ball valve is abutted, is placed at a constant angle in the forward direction of the vehicle with the end on the valve seat side as the center. The ball support is accommodated in the valve chamber so as to be tiltable within an elevation angle range, and the ball support is supported in a floating manner, and the end of the ball support on the opposite side from the valve seat is moved upward in the direction of decreasing the elevation angle of the guide surface. A piston is provided with a spring and further slides in approximately proportion to the increase in oil pressure of the mask cylinder, thereby causing the end of the ball support base opposite to the valve seat to tilt downward in the direction of increasing elevation angle against the spring force. A G-balun characterized in that the G-balun is configured such that the deceleration of the vehicle required for the inertial movement movement that comes into contact with the valve seat of the pol valve increases as the oil pressure of the mask cylinder increases.