JPS6052015B2 - Pedal actuation booster for vehicle brake equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a housing with a hole, an inlet connected to a source of fluid pressure, an outlet connected to a reservoir of fluid, an inlet piston, and a power increasing actuator operating in the hole. The boost piston advances into the bore in response to fluid pressure from a pressure source that compresses a boost chamber in the bore behind the boost piston, and the compression of the chamber by the fluid pressure is compressed by the boost chamber. For vehicles of the type controlled by a control valve device that operates to cut off communication between the outlet and to open communication between the inlet and the boost chamber when the input piston moves in the braking direction. This invention relates to a pedal actuation booster for a brake device.

In the most well-known boosters of the type mentioned above, the power output from the booster is used to absorb the force motion in the braking system before it can be used to actuate the brake system. You have to move the pedal quite a bit at first.

Strain motion in a brake system exists not only in the gaps between the mechanical parts of the system, but also in the elasticity of less rigid parts such as seals, hoses, and brake actuator springs. One attempt to solve this problem is shown in UK Patent Application No. 2013296, in which an input piston is coupled to exert fluid under pressure on the face of a control valve arrangement, A portion of the apparatus is moved relative to the inlet piston in a brake control direction to isolate the boost chamber from the outlet and to place the boost chamber in communication with the inlet.

With this idea, less initial pedal movement is required to cause the initial movement of the input piston, and the remainder of the stroke motion in the system is absorbed by movement of the portion of the control valve system relative to the input piston. A portion of the control valve system moves a fixed distance relative to the input piston. This is configured to absorb the thrust motion and compress the braking device to a relatively low threshold level so that further travel of the pedal activates the brake braking. However, in off-the-shelf boosters, all of the strain motion is not absorbed by the movement of the control valve to create tolerance, or the compression threshold level is too high. Furthermore, when using a tandem master cylinder, if one of the circuits fails, the additional stroke motion caused by the failure must be absorbed by the pedal movement. Similarly, excess brake motion caused by automatic brake regulator failure must be absorbed by pedal movement. According to the invention, in a pedal actuated booster of the type described above, the control valve includes mutually movable parts including a bore and a valve mechanism housed between the bore, a part of the valve mechanism being relative to the input piston. is movable relative to the brake system and has a pressure-responsive surface, the actuation of the control valve is dependent on the pressure of the braking device;
The control valve arrangement is operable upon initial movement of the input piston in the braking direction to compress the brake arrangement to a threshold level and fluid pressure is exerted on a pressure-responsive surface to displace a portion of the valve arrangement relative to the input piston. The boost chamber is placed in communication with the inlet. Since the operation of the control valve system is dependent on the pressure in the brake system, in any booster the control valve system will compress the brake system to a threshold level at which the strain motion in the brake system will be absorbed, thus causing the pedal to depress. By further moving the brake, the braking operation is ensured.

Preferably, the control valve system is operative to compress a chamber in the booster to a predetermined level in order to compress the brake system to a threshold level.

Advantageously, the control valve mechanism includes a two-part valve assembly including an inner spool member that is a part with an outer sleeve member and a pressure responsive surface.

Advantageously, the control valve mechanism operates within the bore of the boost piston. In one configuration of the booster, the control valve mechanism is operable on the first movement of the input piston to cause compression of the boost chamber to a predetermined level and act on the boost chamber to compress the brake system to a threshold level.

In this configuration, the control valve mechanism as a whole is associated with the input piston to accommodate the reaction force applied to the booster from the pressure in the brake system in response to the application of fluid pressure during the initial movement of the input piston. The boost chamber can be moved until a predetermined level of pressure is achieved. It is therefore possible to make the total stroke length of the control valve mechanism equal to the stroke motion that occurs when, for example, the master cylinder circuit fails, and the control valve mechanism therefore compensates for the excess stroke motion with respect to the input piston. I can do things. The control valve mechanism operates into a control chamber where fluid pressure enters from the inlet during the initial movement of the input piston, and the pressure in the control chamber acts on the valve mechanism to transfer it relative to the input piston and into the control chamber. When the boost chamber is compressed to a predetermined level, the valve mechanism operates to trap fluid in a portion of the control chamber, causing the input piston to brake. It is advantageous to prevent further mutual movement of the input piston and the valve mechanism during further movement in the braking direction.

In the valve mechanism, when a predetermined pressure in the boost chamber is reached, the pressure in the control chamber acts on the pressure-responsive surface of the part of the valve mechanism, overcomes the force of the spring, and moves that part relative to the input piston, causing the fluid to flow can be configured to trap in the control room.

Advantageously, this part moves in the braking direction with respect to the input piston. A control chamber is preferably formed in the input piston, and movement of a portion of the valve mechanism preferably closes a valve of the control valve mechanism controlling the association of the control chamber and the inlet.

However, while this configuration has the advantage of shortening the overall length, compressing the boost chamber to a predetermined level does not necessarily compress the brake system to a certain threshold level; changes.

This is because the inlet is normally connected to the control valve via a chamber formed between sealing members spaced around the boost piston, and the forces generated by the pressure in the boost chamber are This is because the frictional forces created by these or other sealing members on the boost piston must be overcome before they can act to compress the brake system.
This frictional force varies depending on the pressure of the fluid supplied from the pressure source. Accordingly, a preferred arrangement includes an auxiliary pressure chamber between the boost chamber and the output piston, and upon initial movement of the input piston, the control valve mechanism opens communication between the auxiliary chamber and the inlet to open the auxiliary chamber. At a predetermined pressure level that acts on the output piston to compress the brake system and is also supplied to the auxiliary chamber, the auxiliary valve closes to trap the fluid in the auxiliary chamber, and then the control valve operates to boost the boost. Open communication between the chamber and the inlet.

This configuration means that the threshold level at which the brake system is compressed is approximately constant.

The forces that must be overcome before compressing the brake system depend on the properties of the auxiliary valve and the auxiliary chamber seal, since they are constant for a given booster. Preferably the auxiliary chamber is located within the boost piston.

The auxiliary valve may include a valve member adapted to close when a predetermined pressure is applied to the auxiliary chamber, which is dependent on the reaction exerted on the booster from the pressure within the brake system. The valve member may include a member urged in a closing direction by a spring and held in an opening direction by a spring-loaded auxiliary piston;
The piston responds to the pressure supplied to the chamber and allows the valve to close when a predetermined pressure is reached. In this configuration, one member of the control valve mechanism is coupled to the input piston, and only the portion having the pressure responsive surface is movable relative to the input piston. Closure of the auxiliary valve increases the pressure of the fluid supplied to the pressure responsive surface, displacing this section relative to the input piston and bringing the inlet into communication with the boost chamber.

Alternatively, occlusion of the auxiliary valve acts directly on and displaces that portion of the valve mechanism, placing the inlet in communication with the boost chamber.

In this case, an auxiliary piston can be connected to that part, so that the piston is provided with a pressure-responsive surface and the piston responds to a predetermined pressure level supplied to the auxiliary chamber so that the auxiliary valve can close. Due to the movement, the part moves slightly to the input piston, connecting the inlet to the boost chamber. Some embodiments of the invention are illustrated in the accompanying figures.

The booster shown in FIG. 1 includes a housing 1 having a longitudinally extending step hole 2. The booster shown in FIG.

An input piston 3 operates into a small diameter section 4 of the stepped bore 2.
The boost chamber 5 is located between the input piston 3 and the large diameter portion 7 of the stepped hole 2.
The boost piston 6 is formed between two operating boost pistons 6, and the boost piston 6 is adapted to operate a master cylinder (not shown). An inlet 8 in the housing connects via a one-way valve 9 to a hydraulic pressure source suitable for an accumulator (not shown) and via a groove 11 and a radial passage 12 of the boost piston 6 to the inlet 10 of the boost piston 6. is connected to. Similarly, an outlet 13 in the housing 1 connects to a tank for liquid fluid (not shown) and a transverse hole 15 in the housing, a localized casting groove 1 in the front end of the housing.
6 and through respective axial and radial passages 18, 19 in the boost piston 6 and the boost piston outlet 1.
is connected to. A control valve arrangement 20 forming part of the control valve arrangement operates in holes 21, 22 formed in the input piston 3 and the boost piston 6, respectively. The movement of the pedal (not shown) is transmitted via the input rod 23 to the input piston 3, which is sealed to its outer end by a sealing member 24.

The input piston 3 has a hole 21 at its inner end, and the piston 3
It is completed with a head 25 having a threaded connection 26 with the inner end of the head. This threaded connection is sealed by a sealing member 27 of a flexible metal material such as rubber or copper. The head 25 has an opening 28 through which the control valve arrangement 20 operates, and the head 25 is provided with a sealing member 29 to form a control chamber 30 within the inlet piston 3 . In the illustrated position, the input piston 3 has an inclined passage 31 providing communication between the control chamber 30 and the outlet 30 via a radial passage 32 and a transverse bore 15 . An annular shingle member 33 sealed at 34 is held between the step shoulder 35 of the step hole 2 and the circlip 36 of the hole section 7, so that even a slight movement of the input piston in the direction of braking will cause the discharge from the tank. The passage 31 is cut off.

In the illustrated retracted position, the boost piston 6 is in contact with the break member 33.

The boost piston 6 has a step hole 37 extending in the longitudinal direction, the inner end of which is closed, and a radial passage 38 communicating with the front chamber 17. The boost piston 6 is held between the shoulder 40 of the step of the bore 37 in the boost piston 6 and the circlip 41 on the boost piston 6, and the control valve 20
The inlet 10 and outlet 14 of the aperture assembly are provided with a aperture assembly 39 constituting the aperture 22 in which the apertures operate.
an annular member 42 having a radial passageway 4 therefrom;
4 extends inward. The annular member 42 has an annular sealing member 45 whose inner diameter is smaller than the inner diameter of the annular member 42.
located between. Sealing member 45 carries each seal 46 to prevent leakage between holes 10 and 14. Boost piston 6 carries seals 47, 48 at each end. The control valve arrangement includes a control valve mechanism 2 operating within the bore assembly 39 and the bore portion 21.
0 and openings in the input piston 3 and in the bore assembly 39 of the boost piston 6.

The control valve mechanism includes an outer open end sleeve 49 and a sleeve 49.
It is a two-part assembly including an inner spool 50 that is movable relative to each other a limited distance.

Sleeve 49 is provided with three opposing holes. The first hole 51 at the inner end of the sleeve 49 is the inlet 10 or the outlet 14.
The second intermediate hole 52 is in communication with the boost chamber 5, and the third outer hole 53 is in communication with the piston head 25.
The control chamber 3 is located between the upper seal 29 and the seal 55 carried by the enlarged head 56 of the sleeve 49 acting on the bore portion 21.
It communicates with an annular space 54 formed at 0. Sleeve 49 is provided with an outer helical groove 57 that controls communication between outlet 14 and boost chamber 5 . A circlip 58 is also located on the outer surface of sleeve 49 at second counterbore 52. A circlip 58 is connectable to the hole assembly 39 to limit movement of the sleeve 49 in the braking direction and
ensures communication with the boost chamber 5 at all times. Spool 5
0 slides inside the sleeve 49.

Spool 50 is a one-piece piece having a conical head at its outer end. Sleeve 49 and spool 50 are pushed rearward by spring 60. A spring 60 acts between the inner end of the boost piston 6 and the plate 61. plate 6
1 is in contact with a circlip 62 provided adjacent to the inner end of the spool 50. The circlip 62 abuts the sleeve 49. The spring 60 determines the pressurization level at which the control valve mechanism 20 moves to pressurize the boost chamber 5 . The spool 50 is provided with an axial blind hole 63 that opens at the outer end of the control chamber 30 . The first one provided at the inner end
A diametric boat 64 controls communication between the blind bore 63 and a first boat 51 of the sleeve 49, and a second diametric boat 65 controls communication between the blind bore 63 and a boat 52 of the sleeve 49. The outer annular recess 66 controls the sleeve 49
The boat 53 and the control room 30 are communicated with each other. The conical head 59 of the spool is provided with a seal 67 which can seat against a corresponding conical surface 67 of the sleeve 49 to trap a quantity of fluid in the annular space 54 . A seal 69 is provided on the spool 50 in front of the first boat 51. In the inoperative state of FIG. 1, with all parts retracted, the control chamber 30 is connected to the tank through an inclined passage 31 and a radial passage 32, and to the discharge boat 14 through a blind hole 63 and boats 64, 51. It is connected.

The boost chamber 5 is also connected to the discharge boat 14 through a helical recess 57 in the sleeve 49 . When applying the brakes, the pedal is depressed and the movement is transmitted to the input piston 3 by the rod 23.

The input piston 3 acts directly on the sleeve 49 and the sleeve 4
9 acts on the spool 50 via the circlip 62;
These three initially move together against the force of spring 60.
The first movement causes the helical groove 57 on the sleeve 49 to break the communication between the boost chamber 5 and the discharge hole. Therefore, the boost chamber 5 is insulated from the tank pressure. At the same time, inclined passage 3
1 moves and joins with the shrunk member 33 to shred the communication between the control chamber and the tank via the passageway 32. This movement also connects the first sleeve hole 51 with the inlet 10,
It allows pressurized liquid to flow into the chamber 30 through the bore 64 and the blind bore 63 and into the annular space 54 through the groove 66 and the third sleeve bore 53. The pressure in the compression chamber 30 acts on the entire area of the control valve mechanism 20 against the force of the spring 60, so that when the pressure is sufficient, the sleeve 49 also pushes against the spool 50.
also moves in the brake control direction and relative to the input piston 3.

Circlip 58 of sleeve 49 mates with hole assembly 39, thereby preventing further movement of sleeve 49. The pressure in chamber 30 continues to rise and acts on the reduced area of the control valve mechanism, spool 50, causing it to move forward against the force of spring 60 in relation to sleeve 49 and input piston 3. A second spool hole 65 is brought into communication with the second sleeve hole 52 and the boost chamber 5 . Therefore, fluid from the inlet 10 can flow to the boost chamber 5. Initially, due to the depressurization of the chamber 30 caused by opening the hole 65 into the boost chamber 5 through the hole 52, the hole 65
Although the opening between the hole 65 and the hole 52 is small, as the pressure in the boost chamber gradually increases, the hole 65 opens completely to the hole 5. Compression of the boost chamber 5 moves the rib-stir piston 6 and starts compression of the brake system.

Sleeve 49 and spool 50 also move with the ribbed piston due to the pressure in chamber 30. Compression of the brake system is initiated by cutting off communication between the first master cylinder pressure space and the tank. This compression creates a reaction force from the master cylinder, which
An increase in the pressure in the boost chamber 5 and the control chamber 30 is caused. When the pressure in the boost chamber 5 reaches a certain level determined by the force of the spring 60 and the cross-sectional area of the spool 50,
The seal 67 on the head 59 of the spool 50
9 to trap a large amount of fluid in the annular space 54. The sleeve 49 is now unable to move forward relative to the input piston 3. This stage of operation is illustrated in FIG. Obviously, the control valve mechanism 20 moves relative to the piston 3 until a predetermined pressure exists in the boost chamber 5, which depends on the pressure of the brake system. This predetermined
The pressure is selected to correspond to the pressure in the brake system at which approximately the full stroke motion is absorbed. If the input piston 3 does not move further, the pressure in the boost chamber will cause the boost piston 6 to move slightly further forward with respect to the control valve mechanism 20, and the introduction hole 10 will be cut off from the first sleeve hole 51 and will not be retained or It becomes an equilibrium position. When the input piston 3 moves further in the brake application direction, the piston moves to the control valve mechanism 2.
0, reconnecting the communication between the inlet 10 and the first sleeve hole 51, and allowing the introduction of pressure fluid into the boost chamber, which is the same as the input piston 3 since there is no stroke motion to absorb. , causing the movement of the boost piston 6.

This stage of operation is illustrated in FIG. Input piston 3
If the force remains constant, the booster will move to the above equilibrium position. When the force of the input piston 3 decreases, the boost pressure acts on the input piston 3 and moves it backwards, the control valve mechanism 20 also moves backwards with the piston 3, and the boost chamber 5 is moved through the helical groove 57. The sleeve is returned to its position relative to the hole assembly shown in FIG. The pressure in the boost chamber decreases, but rather slowly as the rib thrust piston 6 moves rearward due to the reaction from the master cylinder due to the decrease in boost pressure, so the boost chamber 5 is alternately opened and closed. be done. The boost piston 6 returns to the position shown in FIG. When the force on the input piston 3 is completely released, the input piston 3 absorbs the pressure in the chamber 30, the pressure remaining in the boost chamber 5 and the spring 6.
Move backwards by a force of 0.

When the inclined passage 31 again communicates with the tank, the chamber 30
pressure decreases and spring 60 returns sleeve 49, spool 50, and if necessary piston 3 to its retracted position. Normally, the pressure in the boost chamber 5 required to produce the maximum speed reduction is less than the accumulator shear break pressure.

However, if a larger force is applied to the input piston 3, the pressure in the boost chamber 5 will increase. If the force applied to the pedal is large enough, the boost pressure will equalize the pressure in the accumulator. When the input piston 3 moves further, the fluid is moved by the piston 3 to the boost chamber 5,
The boost piston 6 continues to move forward, but the movement of the boost piston is faster than the movement of the input piston. small.
The input piston 3 therefore gradually catches up with the boost piston 6. However, initially the circlip 58 joins the bore assembly 39, so that as the input piston moves further,
The piston moves forward relative to the control valve mechanism 20. The fluid trapped in space 54 thus expands, creating a temporary vacuum. The inner surface 70 of the piston head 25 joins the surface 71 on the boost piston 6, and further movement of the input piston 3 causes the output to increase in proportion to the input. If the boost hydraulic pressure source fails, the control valve 20 will not be able to move relative to the input piston, so further movement of the input piston 3 will cause the face 70 of the head 25 to contact the face 71 of the boost piston 6, causing the master cylinder to operate directly. Obviously, if the master cylinder circuit fails during the initial movement of the input piston 3, the control valve mechanism will operate to absorb the excess stroke motion created.

However, when the booster is in the position shown in Figure 3,
Due to the reduction in the reaction force from the master cylinder felt by the pedal, the pressure in the rib strike chamber is also reduced, and the seal 67 of the spool 50 is opened from the surface 68, allowing the control valve mechanism to operate, resulting in additional stroke motion. Adjust. The seal 24 on the input piston 3 must be leak-tight and is therefore preferably made of a suitable elastomeric material such as rubber.

However, the seals 47, 48 on the boost piston 6
Moving seals, such as seals 55 and 69 on the sprues and sprues, do not need to be leak-tight since there is liquid on both sides of them. These seals are therefore advantageously made of non-elastomeric, low friction materials such as polytetrafluoroethylene (P.T.F.E.) which reduces the sliding friction of the seal and thus the hysteresis of the booster. . FIG. 4 shows a modification of the booster of FIGS. 1 to 3, with corresponding reference numbers being given to corresponding parts. Only the changed parts will be explained below. In the booster shown in FIG. 4, the introduction hole 8 in the housing 1 is connected to the groove 11 and the radial passage 12 in the boost chamber
and is connected to the introduction hole 10 of the hole assembly 39 via the annular groove 72 of the hole assembly 39 . The housing exhaust hole 13 is connected to the exhaust hole 14 of the hole assembly 39 through another annular groove 73, an angled passage 74 of the boost piston, an axial passage 75 of the hole assembly 39, and an annular groove 76. The front chamber 17 is not connected to the tank via the discharge hole 13. The configuration of the input piston is similar to that of FIG. 1, but the inclined passage 31 is replaced by a radial passage 77 connected to the passage 32 and the transverse bore 15 via an annular groove 78 in the housing.

The cutting member 33 is omitted and a seal 79 is provided to facilitate communication between the passage 77 and the groove 78 as the input piston 3 moves in the braking direction. Another seal 80 is provided to seal passage 77 from boost chamber 5 when passage 77 crosses seal 79 due to movement of the input piston. In its retracted position, the boost piston 6 rests against the shoulder 36 of the housing 1.

The boost piston 6 has a stepped through hole 8 extending in the longitudinal direction.
1 and the hole 81 and closes it at its front end, and is sealed from the chamber 17 by a seal 83.
has. Hole assembly 39 includes an integrally molded sleeve member with opposing holes 10 and 14 and grooves 72 and 76;
It is held between the closing member 82 and the shoulder 84 at the stepped portion of the hole 81 . The hole assembly has seals 85, 86 and the hole 10,
14 and the boost chamber 5, the boost piston 6 also has another seal 8 to seal the groove 73 from the chamber 17.
7. Control valve mechanism 20 also includes an outer sleeve and an inner sleeve 50.

The sleeve 49 joins the receiving surface member 88 at its front end, and the sleeve 49 is urged rearwardly by a spring 89 acting between the receiving surface member 88 and the closing member 82 . The receiving surface member 88 is provided with a circlip 90, and a second spring 91 is attached to the circlip 90.
0 and the spool receiving surface member 92 joined to the spool 50, and presses the spool 50 backward. Sleeve member 49 has a stepped hole 93 and three opposing sets of holes.

A first pair of holes 94 at the front end of the sleeve controls communication with the discharge port 14, a second hole 95 controls communication with the introduction hole 10, and a third pair of holes 94 controls communication with the inlet hole 10.
The pair of holes 96 controls communication with the boost chamber 5 . A further radial hole 97 is always in communication with the boost chamber 5. Spool 50 has a stepped profile and operates within hole 93.

Spool 50 carries at its forward end a seal 98 that seals the spool in hole 93 and seals abutment member 92 to the spool. Behind the seal 98 is the spool 5.
0 comprises a first outer annular groove 99, which is connected to a second annular groove 101 via a transverse hole 100, and the second annular groove is connected to the transverse hole 10.
2 to the bore 93 and to the control chamber 30 via a valve formed by the head 59 of the spool 50 which seats on the seat 90 of the sleeve 49 and is capable of trapping fluid into the control chamber 30. ing. In the operating position shown in FIG.
Groove 99, holes 94, 14, passages 76, 75, 74 and groove 7
It is connected to the discharge port 13 via 3.

The boost chamber 5 also has a hole 96, a groove 99, a horizontal hole 100, and a groove 10.
1, horizontal hole 102, chamber 30 and passages 77, 78, 32, 1
It is connected to the discharge port 13 via 5. The chamber 103 formed by the closing member 82 is connected to the outlet 13 via the passage 75.
is connected to. When the brake is applied, rod 23
The movement of the pedal is transmitted to the input piston 3, and the piston 3 is transmitted to the sleeve 49, and between the sleeve 49 and the receiving surface member 8.
8, 92 on the spool 50, so that the three move together.

The initial movement causes the boost chamber 5 to pass through holes 96 and 94.
and the discharge hole 13 are cut off. At the same time, aisle 7
7 moves to break communication between chamber 30 and discharge hole 13. Sleeve 49 is then moved to bring hole 95 into communication with the inlet and pressurized fluid flows through groove 99, hole 100, groove 101, hole 10.
2 to chamber 30. control room 3
A zero pressure acts on sleeve 49 and spool 50, moving them against the force of spring 89 and starting to increase.

At a given pressure in the chamber 30, the force exerted on the spool 50 is sufficient to move it relative to the input piston against the force of the spring 91, putting the groove 101 in communication with the bore 97 and the boost chamber 5 is connected to the inlet 10. Groove 101 of first hole 97
The opening to the chamber 30 is caused by connection with the boost chamber 5.
Although the pressure in the boost chamber 5 increases, the hole 98 opens completely to the groove 102, although it is small due to the pressure decrease in the boost chamber 5.
The rest of the brake braking cycle is the same as that in Figure 1,
The mutual movement of the input piston and the boost piston is accompanied by a corresponding compression of the boost chamber 5 controlled by a control valve arrangement.

When the force on the input piston 3 decreases, the pressure in the boost chamber 5 moves the piston 3 and the valve mechanism 20 to the latter, so that the sleeve hole 94 connects with the discharge hole 14 and the boost chamber 5 connects with the hole 97 and the groove. The discharge holes are connected through holes 99 and 94.

The reduction in pressure in the boost chamber 5 causes the piston 6 to move rearward and alternately open and close communication between the boost chamber 5 and the exhaust hole 14 until an equilibrium position is reached. When the force on the input piston 3 is completely released, the pressure in the boost chamber and the spring 89 causes it to move backwards, and when the passage 77 reconnects with the tank, the pressure in the control chamber 30 decreases and springs 89 and 9
1 returns the sleeve 49 and spool 50 to their retracted position.

When the pressure in the boost chamber 5 becomes equal to the pressure in the accumulator due to the large pressure on the pedal, the input piston 3 moves to the boost piston 6 and the abutment member 88 connects to the closure member 82, thus reducing the input For further movement of the piston 3, the input is mechanically coupled to the boost piston 6 via the fluid in the chamber 30 and the valve mechanism 20.

When the master cylinder circuit fails, the operation of the control valve system to absorb the stroke motion is similar to that of FIG.

FIG. 5 shows a modification of the booster of FIG. 4, with corresponding reference numbers being given to corresponding parts.

In FIG. 5, the length of the booster is reduced by reducing the length of the input piston 3. In the retracted position shown, the control chamber 30 is connected to the passageway 3 via a valve 104 which controls communication with a chamber 105 which is connected to the groove 78 via an inclined passageway 106.
2. Valve 104 includes a valve seat 107 on input piston 3 , which cooperates with a valve member 108 connected to inlet rod 23 . The valve member 108 is pushed rearward by a spring 109 acting between the input piston 3 and the valve member 108 . The remaining configuration of the booster is the same as that in FIG. In operation, the first movement of the inlet rod 23 is transmitted to the input piston 3 via the spring 109 and the fourth
Activate the booster as described in connection with the booster in the figure.

When the inlet rod 23 moves further, the spool 5 suddenly
0 approaches sleeve 49 and traps fluid in chamber 30;
Gradually the force of spring 109 closes valve 104 so that the movement of rod 23 is transmitted via valve member 108 to input piston 3 . The subsequent operation of the booster is the same as described in connection with FIG. Upon brake release, spring 109 opens valve 104 and chamber 30 becomes connected to the tank. In the configurations of FIGS. 1 to 5, compressing the boost chamber 5 to a predetermined level does not necessarily result in compressing the brake system to a certain threshold level. The force generated by the pressure in the boost chamber must overcome the frictional force generated by the spring 1 on the boost piston 6 before it can compress the brake device, and this frictional force is supplied by the accumulator. This is because it changes depending on the pressure of the fluid being used. Figure 6 to 1
Another embodiment of the invention, shown in FIG. 1, is designed to overcome this drawback.

Where appropriate, parts corresponding to those in FIGS. 1 to 5 are provided with corresponding reference numbers. The booster shown in FIGS. 6 and 4 has an input piston 3 and a boost piston 6 operating in a stepped hole in a housing 1, with a boost chamber 5 formed therebetween. In the large diameter section 110 of the stepped throughbore 111 of the boost piston 6 operates an output piston 112 adapted to actuate a master cylinder (not shown). The housing inlet 8 is connected to a suitable hydraulic pressure source, such as an accumulator (not shown), and is also connected to the inlet hole 10 of the boost piston 6 via an annular groove 11 and a radial passage 12 in the boost piston 6. There is. Similarly, the discharge hole 13 of the housing is connected to a tank for hydraulic fluid (not shown), an annular groove 113 of the boost piston 6, an axial passage 115 of the inclined passage 11 and an axial passage 115 of the inclined passage 11.
6 to the discharge hole 14 of the boost piston 6. The inclined passage 114 also provides communication between the portion 117 of the bore 111 and the discharge bore 13 via the annular groove 113. The control valve mechanism 20 is located in the intermediate diameter section 22 of the stepped through bore 111 and in the blind bore 118 of the boost piston 3. The auxiliary pressure chamber 119 and the auxiliary valve 120 are also connected to the boost piston 6.
It is located within the hole 111 of. The input piston 3 is actuated by movement of a pedal (not shown) and is sealed within the bore portion 4 with a seal 24.

In the retracted position shown, the boost piston 6 rests against the rear end 35 of the housing.

The boost piston 6 includes a hole 121 that communicates with the boost chamber 5 via an axial passage 122. The holes 121 are opposed to the discharge holes 14 and, as shown in FIG. prevent it from getting stuck.
Another groove 123 in the boost piston 6 opens into a passage 124 that communicates with the auxiliary chamber 119 . boost piston 6
It also carries seals 1215, 126, 127.
The control valve mechanism 20 is a two-part assembly including an outer sleeve member 49 with a blind bore 128 within which an inner spool member 50 is operated.

The rear end of the sleeve 49 is co-located with the bore 118 of the input piston 3 by a circlip 129 and is provided with three axially spaced bores. A first hole 130 at the front end of the sleeve 49 communicates with a groove 123 in the boost piston 6. The second intermediate hole 131 controls communication with the introduction hole 10 or the discharge hole 14, and also controls the communication between the hole 21 and the discharge hole 14, and controls the communication between the boost chamber 5 and the discharge hole 13. . The third hole 132 communicates with the boost chamber 5. Spring 133 connects boost piston 6 and circlip 1
Receiving surface member 1 held on sleeve member 49 by 35
34 to press the sleeve member 49 rearward. Inner spool member 50 slides within hole 128 and
8 is pushed rearward by a spring 136 acting on a receiving surface member 137 located near the open end.

The spool member 50 includes an axially extending blind hole 138 that opens rearwardly. The first pair of holes 139 at the front end are holes 13
8 and a first hole on the sleeve 49, a second pair of holes 140 controls communication between the hole 138 and an intermediate hole 131 on the sleeve, and a third pair of holes 141 at the rear end controls communication between the hole 138 and the first hole on the sleeve 49. Controls communication between hole 138 and third sleeve hole 132. The sleeve 49 also carries a seal 142 at its forward end, separating the bore portion 117 communicating with the exhaust bore 13 from the bore of the control valve mechanism. A member 143 is connected to the hole 1 of the boost piston 6 in front of the control valve mechanism.
It is located at 11.

Member 143 is located between shoulder 144 of the diameter step of bore 111 and circlip 145 and receives auxiliary valve 120. Valve 120 has an axially extending bore 1 in member 143.
46 and includes a valve member 147 with a seal 148 adapted to seat on a conical portion 149 of bore 146. The valve member 147 is connected to the receiving surface member 1 at the front end of the hole 146.
It has a rearward extension 152 which is urged in the closing direction by a spring 150 acting on bore 146 and which joins to a piston 153 located at the rear end of bore 146 . piston 15
3 is pushed forward by a spring 154 that is stronger than the spring 150 and joins an extension 152 on the valve member 147 to close the valve 1.
20 is held open. The auxiliary chamber 119 is the valve member 14
7 and a seal 155 between the output piston 112 and the portion 110 of the bore 111 of the boost piston 6
formed between. Fluid communication to the auxiliary chamber 119 is provided via an annular groove 156 in the member 143, which communicates with the passage 124 of the boost piston 6 and the radial passage 157 via the auxiliary valve 120. Member 143 also carries seals 158 and 159 and connects groove 156 to auxiliary chamber 119.
and hole portion 117, respectively. Seal 160 on valve piston 153 similarly seals groove 156 from bore 117. In the operating position shown in FIG. 6, all parts are retracted and the boost chamber 5 and the auxiliary chamber 119 are connected to the exhaust hole 13. Hole portion 117 also connects to drain hole 13 . When the brake is applied, the pedal movement is transmitted to the input piston 3 via the input rod.

The input piston 3 acts on the sleeve 49, which acts on the spool 50, so that all three parts act on the spring 133.
At first they move together against the force of. The first movement causes the intermediate hole 131 of the sleeve 49 to move out of alignment with the holes 14 and 121, cutting off the communication between the exhaust hole 13 of the boost chamber 5, so that the boost chamber 5 is arced up under tank pressure. be done. Communication between bore 131 and inlet bore 110 is thus opened, whereby pressurized fluid flows through bores 140, 138, 139 and 130.
, groove 123 , channel 2 channel 156 , channel 157 and opening valve 120 to allow flow to auxiliary chamber 119 .
The pressure in the auxiliary chamber 119 acts on the output piston 112, which moves forward to actuate the master cylinder and begin compression of the brake system.

Initially, the pressure supplied to the auxiliary chamber 119 is slightly low, but as the brake system compresses, a reaction force is applied to the output piston 119.
12, thereby increasing the pressure in chamber 119. The front end of the valve piston 153 is also exposed to this pressure at a predetermined value corresponding to the required threshold level of pressure in the brake system, the pressure acting on the piston 153 overcomes the force of the spring 154, and the piston 153 It moves rearwardly to allow the auxiliary valve 120 to close, trapping fluid in the auxiliary chamber 119 and subsequently acting as a hydraulic strut. When the valve 120 closes, the pressure of the fluid flowing through the valve arrangement increases and the spool 50 is closed at a second predetermined pressure.
The pressure acting on the rear end overcomes the force of spring 136 and spool 50 moves forward, bringing bore 141 into communication with bore 132 and allowing pressurized fluid to flow into boost chamber 5.

Since the total area of the boost piston 6 is larger than that of the output piston 112, the boost chamber 5 is supplied with fluid at a lower pressure than the fluid pressure trapped in the chamber 119 while the reaction load from the master cylinder remains unchanged. Valve 120 is therefore exposed to a pressure differential, thereby keeping the valve closed. Due to the compression of the boost chamber 5, the boost piston 6
advances, the inlet hole 10 moves out of alignment with the hole 131, and if the input piston 3 has not moved past the first stage, the communication between the boost chamber 5 and the inlet hole is interrupted. do. The booster is therefore in a holding or equilibrium position. When the input piston 3 moves further in the braking direction, the piston 3 and the control valve arrangement move together to reestablish communication between the inlet hole 10 and the intermediate sleeve hole 131 and to admit fluid to the boost chamber 5. When the force on the input piston is held constant, the booster moves to the above-mentioned equilibrium position and the pressure in the booster chamber acts over the entire area of the input piston 3, giving a reaction load or sensation to the pedal. . Auxiliary room 11
The pressure at 9 rises and falls with the boost chamber pressure, but at a higher level determined by the area ratio of pistons 6 and 112. Leaking high pressure fluid from chamber 119 through valve 120 or seal 155 only increases piston stroke and does not adversely affect booster operation. As the force on the input piston 3 decreases, the input piston and control valve mechanism move rearwardly, bringing the bore 131 of the sleeve 49 into alignment with the bores 14 and 121, directing fluid from the boost chamber 5 to the passageway 122 to the bore 121. ,131,134
and passages 113, 114, 115, and holes 132, 14
1,140 to the discharge hole 13.
When the pressure in the boost chamber 5 drops to k-bels where the reaction it exerts on the input piston 3 is less than the force exerted on the piston 3 from the pedal, the booster returns to its equilibrium position. When the force on the input piston is completely released, the boost chamber 5 connects with the exhaust hole 13 as described above, and the spring 136 forces the spool 50 rearward, closing the communication between the holes 132 and 141. , the boost chamber 5 still has a passage 122 and a hole 121.
, 131, 14 to the discharge hole 13.

The boost pressure continues to decrease, causing spring 154 to move valve piston and force valve 1 against the pressure in spring 150 and chamber 119.
20 will be released. Fluid from chamber 19 then flows to drain hole 13 via control valve mechanism 120 . Obviously, if the master cylinder circuit fails when the booster is in the inactive position or during the initial movement of the piston 3,
The control valve mechanism 20 operates to absorb the excess mouth motion generated.

If the circuit fails when the booster is activated, the reduction in reaction force causes a decrease in pressure in the auxiliary and boost chambers, allowing the auxiliary valve 120 to reopen and the control valve mechanism to actuate to remove the excess Mouth stroke motion can be corrected. Once compression of the brake system is started by compressing the auxiliary chamber 119, in this embodiment the force that must be overcome before the brake system begins to compress depends solely on the characteristics of the auxiliary valve 120 and the seal of the auxiliary chamber 119. Since it is approximately constant for a given booster, it is certain that the threshold level of the brake system is approximately constant.

FIG. 8 shows a modification of the booster of FIG. 6 in which the booster is connected to a master cylinder 161 and the output piston also acts as a piston for the master cylinder 161.

The booster and master cylinder share a common tank, from which a master cylinder pressure space 162 is supplied via a recovery hole 163. The initial movement of piston 112 moves seal 164, which acts as seal 125 in FIG. 6 to break communication between space 162 and bore 163 and initiate compression of the brake system. The construction and operation of the embodiment of FIG. 8 is otherwise similar to that of FIGS. 6 and 7. 9 and 10 show a modification of the booster shown in FIG. 6, in which the configurations of the spool and auxiliary valve have been changed, and corresponding numbers are attached to corresponding parts.

In the modification shown in FIGS. 9 and 10, the introduction hole 10 is provided in the same axial plane as the hole 1, and is equiangularly spaced around the three holes 10 and the sleeve 49, as shown in FIG. Three holes 123 are provided to prevent the sleeve 49 from getting stuck in the holes 22.

The discharge structure has also been changed, and the discharge hole 14 is replaced by passages 115 and 116.
The groove 113 is replaced by an inclined passage 165 and an axial passage 166.
, and the hole portion 117 is fed by the passageway 114 . The first hole 130 in the upper part of the sleeve 49 controls the communication between the holes 123 and 10, and the second hole 131 controls the communication between the hole 121 and the discharge hole 14.
It controls the communication between. The third hole 132 is connected to the boost chamber 5 as in the previous example. Sleeve 49 also has passage 12
4 and the hole 167 which controls the hole portion 117. The spool itself has also been changed, with three holes 139,
140 and 141 are all connected to annular groove 168. Instead of the bore 138 , a further radial bore 169 is provided which opens into the bore part 117 , so that the bore 138 always communicates with the discharge bore 13 . In this embodiment, spring 136 is omitted and spool 50 is instead located at the forward end of the blind bore of valve piston 153 by pin 170. Auxiliary valve 12
The configuration of the valve piston 153 has also been changed, with the valve piston 153 replacing the bore 146 of the member 143 with the bore 11 of the boost piston 6.
Valve piston 153 operating within 1 is urged into engagement with valve member extension 152 by spring 171 acting against a bearing surface 172 within bore portion 117 .

Booster accumulator 173 and tank 174
The connection to is also shown.

In the non-operating position shown, all parts are retracted and the input piston 3 rests against a circlip on the boost piston 6.

The boost chamber 5, the auxiliary chamber 119 and the hole portion 117 are connected to the discharge hole 13. When the brake is applied, the input piston moves due to the pedal, and the sleeve 49 also moves.
Spool 50 does not move.

In the first movement, hole 131 is severed from holes 14 and 121, the boost chamber 5 is severed from exhaust hole 13, and hole 167 is severed.
is closed to sever communication between passageway 124 and hole 117. Further movement brings aperture 130 into alignment with apertures 10 and 123 to allow fluid to flow from inlet aperture 10 along passageway 124 and through valve 120 into auxiliary chamber 119 . Pressure fluid also flows into the annular groove 168 of the spool 50.
As shown in FIG. 6, when the pressure in the auxiliary chamber 119 increases,
Valve piston 153 moves rearwardly to enable closure of valve 120 and thereby moves spool 50 rearwardly to connect inlet hole 10 to boost chamber 5 via hole 130, groove 168, and hole 132. Make it a continuous relationship. The boost piston 6 then advances to the equilibrium position. The remainder of the operation of this embodiment is similar to that of FIG. 6, with the spool 50 and piston 15
3 returns to its retracted position as soon as the boost piston 6 is fully retracted. In the embodiment shown in FIG. 9, the spool 50
is actuated by a valve piston corresponding to the pressure in the chamber 119, and the hole 138 acts to counteract the force of the spring.
This has the advantage that it is not dependent on internal fluid pressure. This means that compressed fluid cannot enter boost chamber 5 until the pressure in chamber 119 reaches a predetermined level. The embodiment of FIG. 9 is such that the bore 138 of the spool 50 is permanently connected to the tank; therefore, in the embodiment of FIG. 49 and avoids the reaction felt on the pedal sent via the input piston 3. In FIG. 9, only the reaction generated during the initial compression is in chamber 19, which is sent to the housing by boost piston 6. FIG. 11 shows the booster of FIG. 9 connected to master cylinder 161.

In this configuration, the booster and master cylinder have separate fluid supplies, ie, the booster has mineral fluid while the master cylinder uses the vegetable or synthetic fluid of conventional brake systems. Since it is important to keep the two fluids separate, the seal on the boost piston 6 and the master cylinder piston/output piston combination 112
A space 176 is provided between the further fixed seals 177 on which the two slides slide. The space 176 is provided with a drain hole 178 from which fluids leaking into the space 176 through the seals 125, 155 or 177 can be drained, so that the fluids do not contaminate each other. The construction and operation of FIG. 11 is otherwise the same as that of FIG.

[Brief explanation of drawings]

1 is a longitudinal cross-sectional view of the pedal-actuated booster with the booster shown in the retracted position; FIG. 2 is a view of the booster of FIG. 1 in one stage of operation; and FIG. 3 is a view of the booster in another stage of operation. FIG. 4 is a view similar to FIG. 1 of a modified example, FIG. 5 is a partial sectional view of the booster of FIG. 4 showing a modified example, and FIG. 6 is a different booster. 7 is a sectional view taken along line 7-7 in FIG. 6, and FIG. 8 is a partial sectional view showing the booster in FIG. 6 combined with a master cylinder. , FIG. 9 is a diagram similar to FIG. 6 showing a modification, and FIG. 10 is a diagram 10-10 of FIG. 9.
FIG. 11 is a partial sectional view showing the booster of FIG. 9 combined with a master cylinder. 1...Housing, 2...Step hole in housing, 3...
...Input piston, 5...Boost chamber, 6...Boost piston, 8...Housing inlet, 13...
- Discharge port, 20... Control valve mechanism, 22... Control valve hole, 31... Input piston, 50... Control valve mechanism inner spool, 112... Output piston, 119...
Auxiliary pressure chamber, 120... auxiliary valve.

Claims (1)

[Scope of Claims] 1. A housing having a hole, an inlet connected to a fluid pressure source, an outlet connected to a fluid tank, an inlet piston, a boost piston operating within the hole, and the hole. a boost chamber formed behind a boost piston, the boost piston advancing into the bore in response to fluid pressure from a pressure source compressing the boost chamber; The brake system for a vehicle is controlled by a control valve device to disconnect the inlet and the boost chamber when the inlet piston moves in the brake braking direction. In the pedal actuated booster, the control valve device 20, 22 is connected to the hole 2
2 and a valve mechanism 20 housed within the bore, a portion 50 of the valve mechanism being movable relative to the input piston 31 and having a pressure responsive surface;
, 22 is dependent on the pressure in the braking device, and the control valve device 20, 22 is operable on the first movement of the input piston in the direction of braking, compressing the braking device to a threshold level and increasing the fluid pressure to said pressure. A booster characterized in that a portion 50 of a valve mechanism 20 is moved relative to an input piston over a response surface to communicate a boost chamber 5 with an inlet 8. 2. In the booster according to claim 1, the control valve devices 20, 22 operate to compress the booster chambers 5, 119 to a predetermined level, thereby compressing the brake device to a threshold level. A booster featuring. 3. In the booster according to claim 1 or 2, the control valve device 20, 22 is actuable by the initial movement of the input piston 3, and compresses the boost chamber 5 to a predetermined level. and acts on the boost piston 6,
A booster characterized by compressing the brake system to a threshold level. 4. In the booster according to claim 1 or 2, an auxiliary pressure chamber 119 is added between the boost piston 6 and the output piston 112, and on the first movement of the input piston the control valve device 20, 22 operates and the auxiliary pressure chamber 11
9 and the inlet 8, the auxiliary pressure chamber 119 is compressed to act on the output piston, the brake device is compressed, and the auxiliary valve 120 is activated at a predetermined pressure level supplied to the auxiliary pressure chamber 119. occlusion, trapping fluid in the auxiliary pressure chamber 119, and enabling the control valve device to operate the boost chamber 5.
A booster characterized in that communication between the and inlet 8 is opened.