JPH03295746A - Brake hydraulic control device - Google Patents

Abstract

PURPOSE:To simplify a structure by communicating a non-pressure chamber to the outside via ac connection section between the first and second main bodies, and utilizing the dust seal of the connection section as a drain valve in a brake hydraulic control device formed with the non-pressure chamber between a block member and the step section of the main body on the periphery of a piston. CONSTITUTION:A brake hydraulic control device 10 is arranged with a hydraulic control valve 20 and a pulsation damping device 50 in series, and it has a housing 11 constituted of the first main body 111 functioning as the housing of the hydraulic control valve 20 and the second main body 112 functioning as the housing of the pulsation damping device 50. A piston 34 and a pre-load spring 39 are assembled in the main body 111, a piston guide 36 is pressed into it to form the hydraulic control valve 20, and a stepped piston 60 is inserted into a stepped inner hole 51 to form the pulsation damping device 50. A rubber valve element (dust seal) 75 is fitted to seal the connection section of both main bodies 111, 112, and a through hole 77 communicating a non-pressure chamber 76 on the outer periphery of the piston 60 to the outside is opened at this fitting portion.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a technology used in brake circuits of vehicles, etc., and in particular, to increase the braking fluid pressure supplied to the wheel cylinders of a wheel brake device to a predetermined pressure or higher. This invention relates to a brake fluid pressure control device that has both a function of reducing pressure at the wheel brake device side and a function of attenuating the transmission of hydraulic pressure pulsations generated on the wheel brake device side or hydraulic pressure pulsations caused by the pump discharge of the anti-skid brake device to the master cylinder. .

(Prior Art) In general, in the brake circuit of a vehicle, in order to ensure safety during braking, when a predetermined pressure is exceeded, the pressure increase in the wheel cylinder on the rear wheel side is changed to the brake fluid pressure on the front wheel side. Performs control to reduce pressure compared to the corresponding master cylinder side,
The hydraulic pressure control valve is a control device for this purpose, and the screw-in type that is installed by screwing into the discharge part of the master cylinder is well known (for example, see Japanese Utility Model Application Publication No. 1-76362). It is sometimes installed in the middle of the piping connecting the master cylinder and the rear wheel brake actuation device.

For example, a hydraulic control valve includes a main body having an inner hole formed in communication with an inlet and an outlet, a piston slidably inserted into the inner hole of the main body, and an inlet side and an outlet side of the piston. The piston includes a communicating passage, a valve device that closes the passage in response to movement of the piston, and a spring that biases the piston in a direction to open the valve device.

(Problems to be Solved by the Invention) When such a hydraulic pressure control valve is provided in a brake circuit, the piston of the hydraulic pressure control valve may generate abnormal noise due to hydraulic pressure pulsations occurring on the rear wheel brake actuation device side, or There is a problem that damage to the valve device is accelerated. Furthermore, regardless of whether a hydraulic pressure control valve is installed or not, there is a problem in that the hydraulic pressure pulsations can cause discomfort and anxiety to the driver through the brake pedal.

Hydraulic pressure pulsations are noticeable due to the discharge pressure of the pump when an anti-skid device is installed in the rear wheel brake actuating device, but they sometimes occur even when an anti-skid device is not installed. For example, when the left and right suspensions move differently, which affects the operation of the left and right wheel cylinders differently, or when dirt gets caught between the brake drum and the shoe, which affects the wheel cylinders. In such cases, hydraulic pulsations may occur. Therefore, a pulsation damping device is necessary regardless of whether an anti-skid device is installed.

Therefore, in addition to the hydraulic pressure control valve, we considered installing a pulsation damping device to dampen the hydraulic pulsations.

As the pulsation damping device, we decided to use a device that utilizes pulsation damping through a throttle, and to place it in series with the hydraulic control valve. In that case, it is preferable to install the pulsation damping device between the hydraulic pressure control valve and the wheel cylinder side in order to effectively dampen the transmission of hydraulic pressure pulsations from the wheel cylinder side to the master cylinder side. For example, even if an anti-skid device is installed, the rear wheel brake actuation device
Anti-skid control can be performed based on the hydraulic pressure reduced by the hydraulic pressure control valve, and the control becomes easy.

By the way, when both a hydraulic pressure control valve and a pulsation damping device are provided in a brake circuit, it is preferable to integrate the two in order to simplify piping or installation work.

However, if the two are simply integrated, there is a problem in that the integrated device becomes larger. Particularly with screw-in type devices, the larger the size, the more difficult it becomes to install. In addition, in order to fully utilize both the functions of pressure reduction control and pulsation damping, it is necessary to be able to individually inspect the performance of each part of the hydraulic control valve and pulsation damping device when they are still semi-finished products. is desired. Hydraulic pressure control valves can be tested using oil, but the pulsation damping device has a small restriction, and there is a risk that oil may adhere to the restriction and harden and remain. This is because testing using air usually has to be performed.

Based on the results of the above studies, the present applicant has developed a technology that integrates a hydraulic control valve and a pulsation damping device, which allows individual inspection despite being integrated into one body, and which also allows for miniaturization. We first proposed a technology that could also achieve
No. 997), and in the subsequent technology, a cylindrical portion is formed concentrically with each main body of a hydraulic control valve and a pulsation damping device to integrate the two, and necessary parts are installed inside each main body. I try to assemble it in advance.

When implementing the technology related to such a proposal,
A stopper is provided at the opening of each cylindrical portion to prevent internal parts from flying out. Of these stoppers, the side facing the hydraulic control valve is formed of a block member,
Preferably, the member guides the movement of the piston and also defines the return position of the piston.

However, when the block member is used as a stopper on the hydraulic pressure control well side, a pressureless chamber is defined between the block member and the stepped portion of the first main body on the side periphery of the piston. Therefore, in addition to the dust seal provided at the joint between the first main body and the second main body, a drain valve must be provided at the entrance of the passage connecting the pressureless chamber to the outside.

With the above-mentioned background as a background, it is an object of the present invention to provide a technique in which a drain valve communicating with a pressureless chamber is omitted and a dust seal is used as a drain valve.

(Summary of the Invention) In the present invention, the cylindrical portion of the second main body is located inside the first main body and assembled, and is closely engaged with the block member, so that the pressureless chamber is formed between the block member and the first main body. The first body and the second body communicate with each other through a passage formed between the first body and the second body.

Thereby, the pressureless chamber can be communicated with the outside through the joint between the first body and the second body, and the dust seal essential to the joint can also be used as a drain valve.

(Embodiment) First, with reference to FIG. 1, the position of a brake hydraulic pressure control device 10, which is an embodiment of the present invention, in a brake circuit and its basic structure will be explained.

The housing 11 of the brake hydraulic pressure control device 10 is a cylinder extending in the axial direction, and has an inlet 12 at one end and an outlet 13 at the other end. The inlet 12 side communicates with a master cylinder 14 , and the outlet 13 side communicates with a rear wheel brake actuation device 15 . The rear wheel brake actuation device 15 includes not only a wheel cylinder 16 that drives the wheel brake device, but also an anti-skid device 17 that controls the driving pressure of the wheel cylinder 16 to prevent the wheels from locking.

Braking fluid pressure control device! 10 is a hydraulic pressure control valve 20 and a pulsation damping device [50] arranged in series and integrated, with the hydraulic pressure control valve 20 part on the inlet 12 side and the pulsation damping device N50 part on the outlet 13 side. located respectively. The brake hydraulic pressure control device 10 is of a screw-in type, and a thread 12a is cut on the outer periphery of an end 11a of the housing 11 located on the inlet 12 side, and the end 11a is screwed to the discharge part of the master cylinder 14. By this, the master cylinder 14
The 0-
The ring 49 is a seal ring for sealing the joint with the master cylinder 14. On the other hand, the other end 11b of the housing 11 located on the outlet 13 side has a connection port 13a for connecting a pipe, and the connection port 13a is used to connect the pipe 18.
Communication with the rear wheel brake actuation device 15 is performed by.

The housing 11 has a two-part structure including a first main body 111 that functions as a housing for the hydraulic pressure control valve 20 and a second main body 112 that functions as a housing for the pulsation damping device 50. The first body 111 has an outer cylindrical portion 111a on the side opposite to the inlet 12, and an inner cylindrical portion that fits the inner diameter of the outer cylindrical portion 111a is provided on the side opposite to the outlet 13 of the second body 112. There is 112a. The inner periphery of the outer cylindrical portion 111a and the outer periphery of the inner cylindrical portion 112a have a female threaded portion 113f and a male threaded portion 113m, respectively, which are threadedly connected to each other. are integrated with each other by the combination of Of course, in the integrated state, the inner cylinder part 112a and the outer cylinder part 111a are concentrically combined.

Here, before integrating the first and second main bodies 111 and 112, in order to check the performance of the hydraulic pressure control valve 20 and the pulsation damping device 50 individually, the hydraulic pressure control valve 20 and the pulsation damping device 50 are checked individually.
0 and the pulsation damping device [50] can be handled individually as semi-finished products. Next, by sequentially explaining each part of the hydraulic control valve 20 and the pulsation damping device 50, Clarify the point.

The outer cylindrical portion 11 is inserted into the first body 111, which is the housing of the hydraulic control valve 20 of the fIl 120, from the end 11a side where the inlet 12 is located.
There is a stepped first inner hole 21 that penetrates to the inner circumference of 1a. In the middle of the first inner hole 21, there is an inward protrusion or flange 21a on the side closer to the inlet 12. The diameter of the first inner hole 21 increases from the flange 21a toward the inlet 12 side and toward the inner peripheral side of the outer cylindrical portion 111a. Towards the inlet 12 is a medium-diameter groove 23 into which the O-ring 22 is attached. Next, there is a large diameter hole 25 through the stepped portion 24, and the poppet valve body 2 is placed inside the hole 25.
It contains 6. The poppet valve body 26 is biased by the valve spring 28, and the large diameter bottom side is attached to the flange 27a of the cylindrical member 27.
It's hitting the top. The cylindrical member 27 fits into the inner periphery of the hole 25, and the inward flange 27a prevents the O-ring 22 from coming out of the groove 23. Furthermore, one end of the valve spring 28 is supported by the poppet valve body 26, while the other end is supported by a cap member 29. The cap member 29 is made of plastic, and has a plurality of claws 29a on the inner periphery of the outer flange portion, and these claws 29a engage with protrusions on the outer periphery of the housing end portion 11a.

This cap member 29 includes a plurality of auxiliary holes 31 in addition to a central hole 30 that serves as a liquid passage. Cap member 2
In addition to the communication hole 32, the poppet valve body 26 inside the valve 9 has a communication hole 32,
There is a hemispherical protrusion 33 in the center of the bottom side. This protrusion 3
3 faces the valve seat 35 at one end of the piston 34, and can be seated on the valve seat 35 according to the movement of the piston 34.

The piston 34 is a stepped piston with a small diameter portion 3
4a fits into the inner periphery of the flange 21a, and the large diameter portion 34b fits into the center hole 37 of a piston guide 36 made up of a block member. Thereby,
The piston 34 is movable within the first inner hole 21 in the axial direction. The O-ring 22 around the small diameter portion 34a and the O-ring 38 attached to the large diameter portion 34b define the pressure reduction ratio of the hydraulic pressure control valve 20. Under normal conditions, the piston 34 receives the force of the preload spring 39, and the flange portion 3 in the middle of the piston 34
4c- hits the stepped portion 40 provided on the piston guide 36 and is in a stationary state. In other words, the piston guide 36 made of a block member supports the piston 34 by the preload spring 39.
However, when the pressure fluid supplied from the master cylinder 14 side exceeds a predetermined hydraulic pressure value, the difference in pressure acting on both ends of the piston 34 causes the force of the preload spring 39 to The piston 34 is moved toward the poppet valve body 26, and the protrusion 33 of the poppet valve body 26 is seated on the valve seat 35 at the end. From then on, the hydraulic control valve 20
The free flow of liquid through the through hole 34d inside the piston 34 is regulated, and the liquid pressure on the outlet 13 side is reduced at a predetermined rate compared to the inlet 12 side.

Now, if we pay attention to the piston guide 36 which is a block member, the piston guide 36 has a large diameter part 44 on the outer periphery of its central part, and the inlet 1
There is a press-fitting part 45 on the 2 side, and step parts 46 and 47 in two stages on the outlet 13 side. , the two step portions 46 and 47 have a smaller diameter than the one closer to the outlet 13, and an O-ring 48 is attached around the smaller diameter step portion 46. This O-ring 48 is a seal ring for sealing the joint between the first body 111 and the second body 112. The O-ring 48 is stably supported inside a groove formed by a larger-diameter step portion 47 adjacent to the step portion 46 and a stopper plate 70 to be described later.

The piston guide 36 is inserted into the first body 1 by press-fitting the tip 45 into the inner wall 111b around the pressureless chamber 41.
Fixed at 11. For this press fit, the piston guide 36
Some considerations have been made. The first consideration is
By making the tip portion 45 tapered and deformable, deformation due to press fitting is prevented from affecting the stepped portion 40. As a result of the first consideration, the piston guide 36 is press-fitted so that the position of the stepped portion 40 is constant, the amount of compression of the preload spring 39, and the amount of movement of the piston 34 until it hits the poppet valve body 26 (that is, the amount of movement of the piston 34 until it hits the poppet valve body 26) Stabilize the performance of decompression control by eliminating variations in lift amount). The second consideration is the large diameter portion 4 of the piston guide 36.
4 is made larger than the diameter of the inner wall portion 111b which is the press-fitted portion, and the female threaded portion 11 on the first main body 111 side
This point is made slightly smaller than the inner diameter of the prepared hole 21h for 3f. Due to the second consideration, when the piston guide 36 is inserted into the inner periphery of the first main body 111, the female threaded portion 113f is not damaged, and the large diameter portion 44 can be used as a guide for insertion. Can be done. That is, the large diameter portion 44 of the piston guide 36 and the pilot hole 21h on the first main body 111 side surrounding the outer periphery together constitute a guide portion when the piston guide 36 is inserted.

Note that the stepped surface 44 a located at the boundary between the large diameter portion 44 and the stepped portion 47 of the piston guide 36 functions as a stopper when the second main body 112 is screwed to the first main body 111 side.

Such a hydraulic control valve 20 becomes a semi-finished product when necessary parts such as the piston 34 and the preload spring 39 are assembled inside the first main body 111 and the piston guide 36 is press-fitted. Since the semi-finished product independently functions as a hydraulic pressure control valve, its performance can be checked.

Here, please pay attention to the pressureless chamber 41 that is located on the side circumference of the piston 34 and is partitioned between the piston guide 36 and the step formed by the flange 21a of the first main body 111. It must be communicated with the outside atmosphere while preventing the intrusion of dirt and other substances.

Generally, a through hole is provided through the wall of the first body 111,
A drain valve is provided at the opening of the through hole, but in this invention, a drain valve is provided at the press-fit portion 45 of the piston guide 36.
A notch passage 90 is provided to communicate the pressureless chamber 41 and the screw joint. Thereby, the pressureless chamber 41 can be communicated with the outside atmosphere through the notch passage 90 and the threaded joint portion, through which the dust seal 75 is attached, which will be described later. Therefore, a drain valve is not required around the outer periphery of the first main body 111 surrounding the pressureless chamber 41.

゛ 50 pulsation damping devices [2nd body 112 which is a housing of 50
Inside, there is a second inner hole 51 with one step that communicates with the connection port 13a on the outlet 13 side. In the second inner hole 51, the communication hole 52 adjacent to the connection port 13a+ has the smallest diameter, and the diameter gradually increases from there toward the opening on the inner cylindrical portion 112a side.

That is, there is a small diameter hole 53 following the communication hole 52, a medium diameter hole 55 via a stepped portion 54, a first large diameter hole 57 via an inclined portion 56, and a first large diameter hole 57 via a stepped portion 58. It continues with the second large diameter hole 59.

A stepped piston 60, which is a movable body, is inserted into the stepped second inner hole 51.

The stepped piston 60 has a small diameter portion 60a, a medium diameter portion 60b, and a large diameter portion 60cz, depending on the shape of the second inner hole 51 side. Then, an O-ring 61 and a cup seal 62 are placed around the small diameter portion 60a and the large diameter portion 60C.
are held respectively.

The piston 60 also has a through hole 63 passing through the center. The through hole 63 has a large diameter at a large diameter portion 60c, and a poppet type valve body 64 is disposed there. The valve body 64 is biased toward the opening side by a valve spring 68 with a small spring force, and a large diameter portion 64a is seated on the seat member 65.

A notch passage 66 is provided in the large diameter portion 64a of the valve body 64, and the notch passage 66 functions as a throttle for damping pulsation. The seat member 65 is caulked to the opening side end of the large diameter portion 60C of the stepped piston 60.

It is integrated with the piston 60.

Now, normally, the stepped piston 60 is in the state shown in FIG. 1 under the force of the return spring 67, that is, the middle diameter portion 60b
The end portion of is in contact with the stepped portion 54. At this time, the valve body 64 is in contact with the seat member 65. However, the pressure fluid supplied from the master cylinder 14 through the hydraulic pressure control valve 20 pushes the valve body 64 and flows freely, so the notch passage 6
The aperture by 6 does not work. Then, even when the brake fluid pressure increases and control by the anti-skid device 17 starts, the stepped piston 60 remains in the state shown in the figure due to the difference in pressure receiving area defined by the O-ring 61 and the cup seal 62. , so that the pump pulsations of the anti-skid device 17 are effectively damped by the throttling action of the cutout passage 66.

By the way, after the brake operation is finished, the master cylinder 1
When the pressure fluid on the 4 side is relaxed, the pressure on the fluid pressure control valve 20 side becomes negative pressure or a low pressure close to it, while the pressure on the outlet 1
The pressure on the third side is high pressure.

Due to the large pressure difference, the stepped piston 60 deforms the return spring 67 and moves toward the second large diameter hole 59.

As a result of this movement of the stepped piston 60, the tip of the shaft portion 64b of the valve body 64 hits one surface of the stopper plate 70, which is a stopper member, and the valve body 64 separates from the seat member 65. As a result, the throttling effect of the notch passage 66 is released, and the pressure fluid on the wheel cylinder 16 side is quickly relaxed.

Here, attention will be paid to the stopper plate 70, which is a stopper member. As shown in FIG. 2, the stopper plate 70 has a disc shape, and there are a plurality of holes 71 in the disc for passing liquid, and a plurality of holes 71 on the outer periphery of the disc for press fitting. There is a small protrusion 72. This stopper plate 70 is press-fitted into the second main body 112 side so that its negative side is in contact with the stepped portion 58 . Of course, prior to press-fitting the stopper plate 70, the stepped piston 60, the valve body 64, and other internal parts are assembled into the second body 112. Therefore, the press-fitting of the stopper plate 70, that is, the installation Once completed, the pulsation damping device 50 can be handled independently as a semi-finished product.

After press-fitting the stopper plate 70, the pulsation damping device 50
After performing necessary performance checks, it is integrated with the hydraulic pressure control valve 20. The integration is such that the inner cylindrical portion 11 of the second main body 112 is attached to the inner periphery of the outer cylindrical portion 111a of the first main body 111.
This is done by screwing 2a together. At the time of connection, the screwing position is determined by the fact that the tip of the inner cylindrical portion 112a comes into contact with the stepped surface 44a of the piston guide 36.

At this time, in order to avoid unnecessary deformation of the stopper plate 70, the dimensions are set so that a slight gap S remains between the stopper plate 70 side and the end surface of the piston guide 36. Even if such a gap S is provided, since the stopper plate 70 is sandwiched between the piston guide 36 and the stepped portion 58 on the second main body 112 side, there will be no problem even if the press-fit comes off. In order to seal the joint between the first and second main bodies 111 and 112, a belt-shaped rubber valve body (dust seal) 75 is attached, and the outer periphery of the stepped piston 60 is attached to the attached part. No-pressure chamber 76
It is also possible to open a through hole 77 that communicates with the outside.
A notch 8 is provided at the tip of the inner cylindrical portion 112a of the main body 112.
0, but the notch 80 is connected to the hydraulic pressure control valve 20.
After integrating the and pulsation damping device 50, the first body 1
0- for sealing the joint between 11 and the second main body 112
This is a notch for checking whether or not the ring 48 is attached. For example, by closing the outlet 13 side and supplying air from the inlet 12 side, it is possible to check whether or not the O-ring 48 is attached.

If the O-ring 48 were not present, air would escape from the housing 11 through the notch 80 and the threaded joint, so that it is possible to know if the O-ring 48 has been forgotten to be attached.

Although the embodiment shown in FIG. 1 has been described above, the present invention is not limited thereto. A passage corresponding to the cutout passage 90 may also be provided.

In addition, in the example shown in the figure, the piston guide 36 is press-fitted around the entire circumference, but □ Protrusions are provided at multiple locations separated from each other on the outer periphery, and press-fitting is performed at the portions of these multiple protrusions. You can also do that. In that case, the gap between each protrusion functions as a passage corresponding to the notch passage 90. Therefore, there is no need to separately process the notch passage 90.

(Effect of the invention) In this invention, the pressureless chamber 41 on the side circumference of the piston 34 is
Since the dust seal 75 at the joint can be used as a drain valve, the pressureless chamber 41 is communicated with the outside through the joint between the main body 111 and the second main body 112. The configuration for this becomes very simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a brake circuit including a brake hydraulic pressure control device according to an embodiment of the present invention, and FIG. 2 is a front view showing an example of a stopper plate. DESCRIPTION OF SYMBOLS 10... Brake hydraulic pressure control device, 111... First main body, 1lla... Outer cylinder part, 1
12... Second main body, 112a... Inner cylinder part, 11
1b...Inner wall part (press-fitting part). 12... Inlet, 13... Outlet, 14... Master cylinder, 15... Rear wheel brake actuation device, 16... Wheel cylinder, 20... Hydraulic pressure control valve, 21h... Bottom Hole, 36...
Piston guide (block member), 44...large diameter part,
50... Pulsation damping device, 60... Stepped piston (
movable body). 66... Notch passage (aperture), 70... Stopper plate (stopper member), 75...
...Dust seal, 90...Notch passage (passage).

Claims (1)

[Claims] 1. A first body having a cylindrical portion with one end open and the other end serving as a connecting portion connected to a master cylinder, and a piston movably inserted into the first body;
A passage that connects one end of the piston with the other end, a valve provided in the passage that opens and closes in response to the movement of the piston, and limits the rise in pressure at the other end; a preload spring that biases the piston; a block member that is fixed within the cylindrical portion of the first body and guides the movement of the piston and defines the return position of the piston by the preload spring; A second main body is formed as a cylindrical part that is combined with the cylindrical part of the main body, and the other end is a connection part that is connected to the wheel cylinder side, and a second main body that is formed inside the second main body and that is connected to the master from the wheel cylinder side. a throttle that restricts liquid movement toward the cylinder; a movable body that is movably inserted into the second body and releases the function of the throttle when moved toward the master cylinder; a stopper member fixed therein to define a limit of movement of the movable body toward the master cylinder, and a pressureless chamber is defined between the block member and the stepped portion of the first body on the side periphery of the piston; In the brake hydraulic pressure control device, the cylindrical portion of the second main body is positioned inside the first main body and assembled, and is tightly engaged with the block member, so that a pressureless chamber is formed between the block member and the first main body. A brake hydraulic pressure control device that communicates between a first body and a second body through a passage formed between the first body and the second body.