WO2008126941A1

WO2008126941A1 - Vacuum boosting device

Info

Publication number: WO2008126941A1
Application number: PCT/JP2008/057461
Authority: WO
Inventors: Satoru Watanabe
Original assignee: Bosch Corporation
Priority date: 2007-04-11
Filing date: 2008-04-10
Publication date: 2008-10-23
Also published as: JP2008260362A; CN101652281A

Abstract

Provided is a vacuum boosting device (1), in which a BA cylindrical member (33) is held at an inactive position, when at a BA inaction time, by a cylindrical member holding member (35). At an emergency braking time, a retention releasing portion (10a) of a valve plunger (10) pushes the cylindrical member holding member (35) so that the cylindrical member holding member (35) is elastically deformed in a plane normal to the axial direction of the BA cylindrical member (33). Then, the retention of the BA cylindrical member (33) by the cylindrical member holding member (35) is released, and the BA cylindrical member (33) is moved to a predetermined extent by a BA action spring (34), so that a vacuum valve seat member (30) and a valve member (12) move backward to predetermined extents. As a result, an atmospheric valve has a larger opening than that of the ordinary time thereby to have a higher output.

Description

Specification

Negative pressure booster

[0001] The present invention relates to a technical field of a negative pressure booster used for a brake booster or the like. In particular, when an emergency brake is operated, the same input (brake operating force) as that during a normal operation is used. The present invention relates to the technical field of negative pressure boosters that can obtain a large output. In the claims and the description of the claims, “forward” refers to the direction in which the input shaft advances (ie, the operating direction) by input, and “rearward” refers to the direction in which the input shaft returns due to the disappearance of input.

Conventionally, in a brake system for automobiles such as passenger cars, a negative pressure booster using negative pressure is used as a brake booster. In such a conventional general negative pressure booster, when the input shaft moves forward during normal braking by normal depression of the brake pedal, the valve plunger connected to this input shaft also moves forward, and the valve body The valve body of the control valve arranged in the valve seat is also seated on the vacuum valve seat formed on the valve body and the vacuum valve is closed, and the atmospheric valve seat formed on the valve plunger is The air valve opens away from the body, and the variable pressure chamber in which negative pressure is introduced when not in operation is shut off from the constant pressure chamber in which negative pressure is always introduced and communicated with the atmosphere. Then, the air is introduced into the variable pressure chamber through the open atmospheric valve, and a differential pressure is generated between the variable pressure chamber and the constant pressure chamber, so that the power piston moves forward, and the valve body and the output shaft move forward, resulting in negative pressure. The booster boosts the input of the input shaft (ie, pedaling force) with a predetermined servo ratio and outputs it. By the output of this negative pressure booster, the mass cylinder cylinder biston moves forward, the master cylinder generates mass cylinder pressure, the wheel cylinder operates with this mass cylinder pressure, and the normal brake is activated.

[0003] At this time, as shown in FIG. 6 in normal operation, the negative pressure booster generally does not transmit the reaction force from the output shaft to the input shaft when the input is small. When the reaction force is transmitted to the input shaft by the reaction force mechanism, it is substantially predetermined It has an input / output characteristic that has a so-called “Jambling” (JP) characteristic.

[0004] By the way, in an emergency braking, it may be necessary to generate a desired braking force more quickly and more quickly than when normal braking is activated from the start of depression of the brake pedal during emergency braking. Therefore, as a negative pressure booster used in the brake system, a negative pressure booster equipped with a BA mechanism for brake assist (hereinafter also referred to as BA) control that quickly generates a large brake force with a small pedal effort. A force device is proposed in Japanese Patent Application Laid-Open No. 2 0 0 4-1 7 7 4 0.

In the negative pressure booster disclosed in Japanese Patent Laid-Open No. 2 0 0 4-1 7 7 4 0, a cylindrical member having a vacuum valve seat is provided on a valve body so as to be slidable relative to the valve body. The cylindrical member is always urged by a spring in the direction in which the atmospheric valve opens, and the cylindrical member is normally held in the non-operating position by the holding means. Then, the sudden movement of the pedal, which is faster than the normal speed, causes the valve plunger to move forward at a speed faster than the normal speed and release the holding of the cylindrical member by the holding means. Move the air valve in the opening direction to open it larger than usual. As a result, the amount of jeaming of the negative pressure booster increases from the normal time, and the output increases rapidly. In this way, BA control during emergency braking is performed.

[0006] Incidentally, the BA mechanism in the negative pressure booster disclosed in Japanese Patent Laid-Open No. 2 00 4-1 7 7 40 has a holding means for holding the cylindrical member in a non-operating position during normal operation. However, the holding means is provided on the cylindrical member and pressed by the valve plunger. The cylindrical member is provided on the cylindrical member so as to be positioned axially forward of the pressed portion. It consists of a member-side hook and a holder-side hook provided on a holder fixedly supported on the valve body. In the normal state, the tubular member side hook is engaged with the holder side hook, and the tubular member is held in the non-operating position. Also, when the valve plunger moves forward at a faster speed than usual during an emergency brake operation, the valve plunger presses the pressed part so that the pressed part and the cylindrical member side hook are provided. Part of member Since the minute elastically crawls in the plane passing through the central axis of the cylindrical member (that is, the central axis of the valve body 4), both hooks are disengaged, and the cylindrical member opens with the spring as the atmospheric valve. To move to.

However, in this negative pressure booster, as described above, the engagement position between the tubular member side hook and the holder side hook is located in front of the pressed portion and passes through the central axis of the tubular member. Since it is partially and elastically held in the plane, the holding means becomes longer in the axial direction, resulting in a larger structure. Further, the cylindrical member not only has a vacuum valve seat but also has a pressed portion and a cylindrical member side hook, and a cylindrical shape in which these pressed portion and the cylindrical member side hook are provided. Since the member portion is elastically deformed, the cylindrical member has a complicated structure. As described above, the B A mechanism of the negative pressure booster disclosed in Japanese Patent Application Laid-Open No. 2 044 _ 1 7 7 40 has a large and complicated structure. Disclosure of the invention

[0008] An object of the present invention is to provide a negative pressure booster capable of making the BA mechanism more compact and compact and with a simple structure.

[0009] In order to achieve this object, a negative pressure booster according to the present invention includes a valve body disposed in a shell so as to freely advance and retreat, the valve body being provided with the shell. A power piston that partitions a constant pressure chamber into which negative pressure is introduced and a variable pressure chamber into which air is introduced during operation; a valve plunger that is connected to the input shaft and is slidably disposed within the valve body; A vacuum valve that has a valve body and a vacuum valve seat on which the valve body can be seated and separated, and that controls communication or blocking between the constant pressure chamber and the variable pressure chamber by operation of the valve blanker; And an atmospheric valve seat on which the valve body can be seated / separated, an atmospheric valve that controls or communicates between the variable pressure chamber and at least the atmosphere by the operation of the valve plunger, and the input shaft is usually When moving faster than the moving speed during operation In the negative pressure booster comprising at least an operation assisting mechanism that moves to increase the output from the normal time, the atmospheric valve is provided in the valve body and can be separated from and seated on the atmospheric valve seat The vacuum valve is provided on the valve body and The vacuum valve seat has a vacuum valve portion that can be attached to and detached from the vacuum valve seat, the vacuum valve seat is provided to be movable relative to the valve body, and the vacuum valve portion and the atmospheric valve portion are moved to the body. A cylindrical member configured to move the vacuum valve portion and the atmospheric valve portion rearward with respect to the valve body by a predetermined amount via the vacuum valve seat during operation, and A cylindrical member holding member that holds the cylindrical member in a non-operating position, and the cylindrical member is slidably provided on the valve body and is always urged rearwardly, When the cylindrical member holding member is pressed by the valve plunger when the input shaft is moved faster than the moving speed during normal operation, the cylindrical member holding member is in a plane perpendicular to the axial direction of the cylindrical member or The axial direction of the cylindrical member In orthogonal plane by elastic deformation is characterized in a release child holding the inoperative position of the tubular member.

In addition, a negative pressure booster according to the present invention includes a valve body that is disposed so as to be movable forward and backward with respect to the inside of the shell, and a constant pressure chamber that is provided in the valve body and into which the negative pressure is introduced into the shell. A power piston that is partitioned into a variable pressure chamber into which air is introduced during operation, a valve plunger that is connected to the input shaft and is slidably disposed within the valve body, and a valve body and the valve body A vacuum valve seat that can be separated, and a vacuum valve that controls communication or blocking between the constant pressure chamber and the variable pressure chamber by operation of the valve plunger, and the valve body and the valve body are seated and separated An atmospheric valve seat that is capable of shutting off or controlling communication between the variable pressure chamber and at least the atmosphere by the operation of the valve plunger, and the input shaft is faster than the moving speed during normal operation. Operates when moved and outputs greater than normal In the negative pressure booster comprising at least a squeezing operation assist mechanism, the atmospheric valve includes an atmospheric valve portion provided in the valve body and separable from and seated on the atmospheric valve seat, and the vacuum A valve provided on the valve body and having a vacuum valve portion that can be separated from and seated on the vacuum valve seat; the vacuum valve seat is provided to be movable relative to the valve body; and the vacuum valve portion And the atmospheric valve portion are movable to the body, and the operation assist mechanism moves the vacuum valve portion and the atmospheric valve portion rearward with respect to the valve body via the vacuum valve seat during operation. Moved by a certain amount And a cylindrical member holding member that normally holds the cylindrical member in a non-operating position, and the cylindrical member is slidably provided on the valve body. The cylindrical member holding member force is always urged rearward, and when the input shaft is moved faster than the moving speed during normal operation, the cylindrical member is elastically deformed by being pressed by the valve plunger. The holding of the non-operating position of the member is released, and further, the pressed portion of the cylindrical member holding member pressed by the valve plunger and the holding of the cylindrical member in the cylindrical member holding member The first and second portions are provided at positions near each other in the axial direction of the cylindrical member.

[0011] Further, in the negative pressure booster according to the present invention, the cylindrical member holding member is made of an elastic rod-shaped member formed in a U-shape, and the rod-shaped member is a shaft of the cylindrical member. The holding of the non-operating position of the cylindrical member is released by elastic deformation in a plane orthogonal to the direction or in a plane substantially perpendicular to the axial direction of the cylindrical member.

[0012] According to the negative pressure booster according to the present invention configured as described above, a cylindrical member holding member separate from the cylindrical member is provided, and the cylindrical member holding member is attached to the cylindrical member. The cylindrical member holding member can be further shortened in the axial direction because it is elastically deformed in a plane orthogonal to the axial direction or almost in the plane, and the brake assist mechanism is effectively reduced accordingly. In addition, it can be formed into a compact package.

[0013] Further, since the cylindrical member holding member is elastically deformed, it is not necessary to elastically deform the cylindrical member, and it is only necessary to simply hold the cylindrical member by the cylindrical member holding member. The cylindrical member can have a simpler structure. In addition, the cylindrical member can be further simplified by not providing the vacuum valve seat on the cylindrical member.

[0014] Also, a cylindrical member holding member separate from the cylindrical member is provided, and a pressed portion of the cylindrical member holding member pressed by the valve plunger and a holding portion of the cylindrical member in the cylindrical member holding member Are disposed near each other in the axial direction of the cylindrical member, so that the cylindrical member holding member can be shortened in the axial direction of the cylindrical member. Therefore, the brake assist mechanism can be effectively made compact and compact.

[0015] Further, since the cylindrical member holding member is elastically deformed, it is not necessary to elastically deform the cylindrical member, and it is only necessary to simply hold the cylindrical member by the cylindrical member holding member. The cylindrical member can have a simpler structure. In addition, the cylindrical member can be further simplified by not providing the vacuum valve seat on the cylindrical member.

[0016] In particular, since the cylindrical member holding member is composed of an elastic rod-shaped member formed in a U-shape, it can be formed in a more compact and simpler structure. Brief Description of Drawings

[0017] FIG. 1 is a cross-sectional view showing an example in which the negative pressure booster according to the present invention is applied to a brake booster in a non-operating state.

FIG. 2 is a partially enlarged cross-sectional view showing the vacuum valve and the atmospheric valve in FIG.

FIG. 3 is a diagram for explaining the operation of the vacuum valve seat member in the negative pressure booster of the example shown in FIG. 1 and showing a mechanically equivalent state.

4A and 4B illustrate the characteristics of the negative pressure booster of the example shown in FIG. 1. FIG. 4A is a diagram illustrating the input stroke output stroke characteristics, and FIG. 4B is a diagram illustrating the input-output characteristics.

5A is a partial cross-sectional perspective view showing the BA mechanism of this example, and FIG. 5B is a perspective view of a cylindrical member holding member.

FIG. 6 is a partially enlarged sectional view similar to FIG. 2 showing another example of the embodiment of the negative pressure booster according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example in which a negative pressure booster according to an embodiment of the present invention is applied to a brake booster used in a brake system in a non-operating state.

2 is an enlarged partial sectional view showing the vacuum valve and the atmospheric valve in FIG. In the following description, “front” and “rear” indicate “left” and “right” in each figure, respectively.

First, in the negative pressure booster of this example, the same components as the conventional negative pressure booster described in Patent Document 1 and the configuration of the negative pressure booster described in Patent Document 1 are different. Components that are not directly related will be briefly described. In FIGS. 1 and 2, 1 is a negative pressure booster, 2 is a front shell, 3 is a rear shell, 4 is a valve body, 5 is a valve attached to the valve body 4 —piston member 6 and valve body 4 and both A single piston consisting of a diaphragm 7 provided between the shells 2 and 3, 8 is one of two chambers divided by the power viston 5 in the space inside the shells 2 and 3, and a negative pressure is normally introduced. 9 is the other of the above two chambers, a variable pressure chamber in which atmospheric pressure is introduced when the negative pressure booster 1 is operated, 10 is a valve plunger, and 11 is connected to a brake pedal (not shown). , And an input shaft for controlling the operation of the valve plunger 1 0, 1 2 is provided in the valve body 4 so as to be airtight and slidable, and the atmospheric valve portion 1 2 a and the vacuum valve portion 1 2 b are integrated with each other. A valve body having a coupling 1 2 c for movably coupling, 1 3 An annular vacuum valve seat, 14 is an annular atmospheric valve seat formed on the valve plunger 10, 15 is a vacuum valve composed of the vacuum valve section 1 2 b and the vacuum valve seat 1 3, 16 is Atmospheric valve composed of atmospheric valve section 1 2 a and atmospheric valve seat 1 4, 17 consists of vacuum valve 15 and atmospheric valve 16 arranged in series with each other, A control valve that selectively switches between chamber 8 and the atmosphere, 1 8 is the first valve control that always urges the valve body 1 2 in the direction in which the vacuum valve section 1 2 b is seated on the vacuum valve seat 1 3. A spring, 19 is an air introduction passage composed of an outer peripheral passage 19a of valve valve 4 and an inner peripheral passage 19b communicating with this, and 20 is attached between Riyashiel 3 and the input shaft 11 And a boot having an air inlet 20 0 a, 2 1 is a silencer provided at the air inlet 20 0 a to reduce noise generated by the control valve 17, 2 2 is a vacuum passage, 2 3 is a valve body 4 The relative movement of the valve plunger 10 with respect to the valve body 4 by being inserted into the key hole 4a formed in the valve is restricted to a predetermined amount defined by the axial width of the key hole 4a, and the valve body 4 and valve plunger 10 Key members that define the retreat limit, 2 4 Spacing member, 2 5 Reaction disk, 2 6 Output shaft, 2 7 Return spring, 2 8 shown This is a negative pressure inlet for introducing the negative pressure from the negative pressure source into the constant pressure chamber 8.

[0020] When the negative pressure booster 1 is not in operation, there is a shaft between the front end face of the spacing member 24 and the rear end face of the reaction disk 25 facing the front end face of the spacing member 24. A predetermined gap C in the direction is set.

Although not shown, like the conventional general negative pressure booster, the rear end of the mass cylinder passes through the front shell 2 and enters the constant pressure chamber 8, and the mass cylinder piston outputs. Actuated on axis 26. Note that the through-hole portion of the front shell 2 of the mass cylinder is sealed by an appropriate sealing means (not shown), and the constant pressure chamber 8 is hermetically shut off from the atmosphere. Further, as in the prior art, the valve body 4 penetrates the lyezel 3 so as to be movable, and the variable pressure chamber 9 is hermetically shut off from the atmosphere by the seal member 29 shown in the penetration portion.

Next, the configuration of the characteristic part of the negative pressure booster 1 of this example will be described.

As shown in FIG. 2, in the negative pressure booster 1 of this example, a vacuum valve seat member 30 that is a cylindrical member is slidably fitted in the axial inner hole 4 b of the valve body 4. The vacuum valve seat 13 is provided on the inner peripheral side of the rear end of the vacuum valve seat member 30. Therefore, the vacuum valve seat 1 3 can also be moved relative to the valve body 4.

[0022] And, by a seal member 31 such as a cup seal provided on the outer peripheral surface of the vacuum valve seat member 30, the inner peripheral surface of the inner hole 4b of the valve body 4 and the vacuum valve seat member 30 are The space between the outer peripheral surface and the outer peripheral surface is kept airtight so as to prevent air flow from at least the front end to the rear end of the vacuum valve seat member 30. Further, the front end face 30 a of the vacuum valve seat member 30 is always in communication with the variable pressure chamber 9, and the pressure of the variable pressure chamber 9 is always applied to these front end faces 30 a. [0023] Further, in a state where the vacuum valve portion 12b of the valve body 12 is seated on the vacuum valve seat 13, the vacuum valve portion 12b on the rear end face 30b of the vacuum valve seat member 30 The annular outer rear end surface portion on the outer peripheral side from the seating position is in communication with the constant pressure chamber 8 at all times, and the pressure (negative pressure) of the constant pressure chamber 8 always acts on the outer rear end surface. Accordingly, when the negative pressure booster 1 is in operation, if a pressure difference occurs between the pressure in the variable pressure chamber 9 and the pressure in the constant pressure chamber 8, force due to this pressure difference is applied to the vacuum valve seat member 30 backward. It becomes like this.

[0024] Further, the vacuum valve seat member 30 is provided with an extension arm portion 30c so as to extend axially forward from the front end surface 30a of the vacuum valve seat member 30. The extension arm portion 30 c is formed with an axial hole 30 d.

Between the outer peripheral side of the rear end face 30 b of the vacuum valve seat member 30 and the valve body 4, there is a second valve control spring 3 2 (corresponding to the urging means of the present invention) composed of an annular leaf spring. The vacuum valve seat member 30 is contracted in series with the vacuum valve seat member 30, and the second valve control spring 32 always urges the vacuum valve seat member 30 forward.

Next, the operation of the vacuum valve seat member 30 of this example will be described. The operation of the vacuum valve seat member 30 is the same as that of the vacuum valve seat member described in the above-mentioned Japanese Patent Laid-Open No. 2 00 4-1 7 Since it can be easily understood by referring to the gazette, it will be briefly described here.

When the negative pressure booster 1 is not in operation, the vacuum valve seat member 30 is positioned at the position shown in FIG. 2 where the front end face 30 a abuts against the stepped portion 4 c of the valve body 4. The vacuum valve seat 13 in such a positioned state is set so as to be in the same state as the vacuum valve seat formed on the valve body 4 of the conventional general negative pressure booster. Therefore, at this position of the vacuum valve seat member 30 when the negative pressure booster 1 is not in operation, the vacuum valve section 1 2 b does not sit on the vacuum valve seat 1 3 and the vacuum valve 15 opens. Become.

[0026] In addition, when an input is applied to the input shaft 11 by depressing the brake pedal and the negative pressure booster 1 is activated, the atmosphere is introduced into the variable pressure chamber 9 as in the case of a conventional general negative pressure booster. Thus, a pressure difference is generated between the variable pressure chamber 9 and the constant pressure chamber 8. For this reason, a force due to this pressure difference is also applied to the vacuum valve seat member 30 backward. It comes to be. This force has a magnitude corresponding to the pressure difference between the variable pressure chamber 9 and the constant pressure chamber 8, that is, the magnitude of the input applied to the input shaft 11. When the negative pressure booster 1 is in operation, the vacuum valve portion 1 2 b is seated on the vacuum valve seat 13.

[0027] The force due to the pressure difference is equal to or less than the sum of the spring load of the second valve control spring 32 and the spring load of the first valve control spring 18 of the valve body 12 at this time (that is, the input The input applied to the shaft 1 1 is the preset setting input F. The following (F. is shown in FIG. 4) and the vacuum valve seat member 30 does not move relative to the valve body 4. FIG. And the inactive position shown in Fig. 2 is maintained. When the force due to the pressure difference becomes larger than the sum of the two spring loads (that is, the input applied to the input shaft 1 1 becomes larger than the set input F.), the vacuum valve seat member 30 becomes the valve body 1 The vacuum valve part 1 2 b of 2 is moved backward relative to the valve body 4 while pushing. Therefore, when the vacuum valve seat member 30 moves rearward, the vacuum valve seat 13 protrudes backward from the normal position.

[0028] By the way, when the vacuum valve seat member 30 makes a stroke relative to the valve body 4, the atmospheric valve portion 1 2a of the atmospheric valve 16 also has a vacuum valve seat member 30 with respect to the valve body 4. Relative strokes are made backward as much as the relative stroke amount of. Therefore, the balance position of the control valve 17 where both the vacuum valve 15 and the atmospheric valve 16 are closed moves backward. Therefore, the input stroke amount of the input shaft 1 1 compared to the case where the opening amount between the atmospheric valve section 1.2a and the atmospheric valve seat 14 is not relative to the vacuum valve seat member 30. Are the same, the relative stroke amount of the vacuum valve seat member 30 increases. That is, in the intermediate load state where both the vacuum valve 15 and the atmospheric valve 16 are closed and balanced, if the input stroke amount of the input shaft 1 1 is the same, the valve body 4 and the piston-biston member 6 of the piston 5 Each stroke is increased by the relative stroke amount of the vacuum valve seat member 30 as compared with the case where the vacuum valve seat member 30 is assumed not to move relative to each other. In other words, it is assumed that the stroke amount of the valve body 4 and the piston member 6 of the part biston 5 is the same when the relative stroke of the vacuum valve seat member 30 is assumed and when the relative stroke is not assumed. Then, when the relative stroke of the vacuum valve seat member 30 is made, the stroke of the input shaft 11 is shortened by the relative stroke amount of the vacuum valve seat member 30.

[0029] On the other hand, when the above-mentioned vacuum valve seat member 30 has a relative stroke, the output shaft 26 of the output shaft 26 also has the same input stroke amount of the input shaft 11 as described above. Increased as the strokes of the valve body 4 and the piston member 6 of the power piston 5 increase. However, in the intermediate load state, the reaction disk 25 expands toward the spacing member 24 as in the case of the conventional negative pressure booster, and the thickness of the reaction disk 25 decreases in the axial direction. It becomes smaller than the increased relative stroke amount of each stroke of the piston member 6 of the body 4 and the part piston 5.

[0030] Since the vacuum valve seat member 30 protrudes backward while pushing the vacuum valve portion 1 2 b of the valve body 12 2, the valve body 12 moves backward, and the valve body 12 The atmospheric valve section 1 2 a also moves backward. For this reason, the atmospheric valve portion 1 2 a is further separated from the atmospheric valve seat 14 than when the atmospheric valve 16 is closed during normal braking operation. That is, the opening amount of the atmospheric valve 16 is increased. In this way, the operation of the vacuum valve seat member 30 is controlled by the pressure difference between the pressure in the variable pressure chamber 9 and the pressure in the constant pressure chamber 8.

[0031] The movement of the vacuum valve seat member 30 will be specifically described. Due to the pressure difference applied to the vacuum valve seat member 30 when the vacuum valve seat member 30 is moved and the vacuum valve 15 and atmospheric valve 16 are both closed and the control valve 17 is in a balanced state. Think of power. The balanced state of the control valve 17 is that the vacuum valve seat member 30 and the valve body 12 are brought into contact with each other and integrated with each other, so that the vacuum valve seat member 3 integrated with each other as shown in FIG. It can be regarded as an equivalent state of the force applied to 0 and the valve body 1 2.

[0032] Now, in Fig. 3, FP is the force due to the pressure difference applied to the vacuum valve seat member 30 and the valve body 12, PVQ is the pressure in the constant pressure chamber 8, and P v is the pressure in the variable pressure chamber 9. The force FP due to the pressure difference applied to the vacuum valve seat member 30 and the valve body 12 is FP

FP = - given by (P v P vo) · (effective pressure receiving area difference between the vacuum valve seat member 3 0), toward the force F _P is the vacuum valve seat member 3 0 and the valve body 1 2 to the rear And come to press.

On the other hand, the spring load Fs of the second valve control spring 32 and the spring load f _{s of} the first valve control spring 18 are pressed forward. Therefore, the sum of the previous the mosquito F _P predicates is less than the sum of these spring load (Fs + fs), the vacuum valve seat member 30 is not moved relative to the valve body 4, also the force F _P spring load ( When it becomes larger than Fs + fs), the vacuum valve seat member 30 moves rearward with respect to the valve body 4. Here, the absolute value of the spring load fs of the first valve control spring 18 is small, and is extremely small compared to the spring load Fs of the second valve control spring 32 (Fs >> f _s ). When the force F _P is greater than the spring load Fs (F _P > FS), the vacuum valve seat 30 moves backward with respect to the valve body 4 and the force F _P is less than the spring load Fs (F _P ≤FS), the vacuum valve seat member 30 does not move backward with respect to the valve body 4. That is, the operation start of the vacuum valve seat member 30 is substantially determined by the second valve control spring 32. Thus, varying the pressure of the pressure chamber 9 is increased, the force F _P is greater than the set spring load, so that vacuum valve seat member 30 starts moving backward.

[0034] Then, as shown in FIG. 4, the area of the pressure Pv in the region, that the variable pressure chamber 9 of the force F _P vacuum valve seat member 30 is not moved rearward relative to the valve body 4 is applied to the input shaft 1 1 The input to be set is input F. The following areas. The saturation ratio S in this region is small, and therefore the output is relatively small as shown by the solid line in FIG.

[0035] Further, in the region of force FP in which the vacuum valve seat member 30 moves rearward with respect to the valve body 4, that is, the region of pressure Pv in the variable pressure chamber 9, the input applied to the input shaft 11 is the setting input F. It is a larger area. The servo ratio SR ₂ in this region is larger than that during normal braking when the opening amount of the atmospheric valve 16 is the same, so the servo ratio SR ₂ (SR ₂ > SRi) It becomes. Therefore, in the intermediate load state of the negative pressure booster 1, the output becomes larger than that at the saturation ratio SRi as shown by the solid line in FIG.

In the negative pressure booster 1 of this example, the vacuum valve seat member 30 is moved and opened as described above. Both the spring constant and set spring load of the second valve control spring 3 2 that determines the start can be set arbitrarily. Therefore, in the input / output characteristics of the negative pressure booster 1 in this example shown in FIG. 4, the change point (ratio point) at which the small servo ratio S changes to the large servo ratio SR ₂ is reached. Setting input F which is input of. Can be raised and lowered by changing the set spring load of the second valve control spring 3 2. In addition, it is possible to change the magnitude ratio SR of the negative pressure booster 1 by changing the spring constant of the second valve control spring 3 2.

[0037] Therefore, the negative pressure booster 1 in this example sets various types of vehicles in one form by setting the spring constant of the second control valve spring 3 2 and the set spring load according to the vehicle on which it is mounted. The brake booster can be applied easily and more accurately according to the type of vehicle.

As shown in FIGS. 1, 2 and 5 (a) and (b), a brake assist mechanism (BA mechanism) which is an operation assist mechanism of the present invention is placed in the axial hole of the valve body 4. 3) is provided. The B A mechanism 36 includes a B A cylindrical member 33 disposed so as to be slidable relative to the valve body 4. An annular flange 3 3 a protruding outward is formed at the rear end of the BA tubular member 3 3, and an axial hole 3 3 b is formed in the central portion of the BA tubular member 3 3. Further, an axial hole 33c is also formed in the front end portion of the BA tubular member 33. Between the flange 3 3 a and the valve body 4, a BA actuating spring 3 4 is contracted and the BA tubular member 3 3 is always attached rearward by the spring force of the BA actuating spring 3 4. It is energized. When the BA tubular member 3 3 strikes the valve body 4 backward for a predetermined stroke or more, the rear end surface 3 3 e of the BA tubular member 3 3 becomes the front end surface 3 0 of the vacuum valve seat member 30. By abutting against a and pressing the vacuum valve seat member 30 backward against the spring force of the second valve control spring 3 2, the BA tubular member 3 3 moves the second valve control spring 3 2 The vacuum valve seat member 30 is moved rearward with respect to the valve body 4 by being reduced.

[0039] Then, the key member 23 is connected to the axial hole 33b of the BA tubular member 33 and the extension. The long arm portion 30 c is also provided through the axial hole 30 d. As shown in FIG. 2 in an enlarged manner, when the negative pressure booster 1 is not in operation, the axial member 3 in the vacuum valve seat member 30 is connected to the key member 23 that is in contact with the rear shell 3 and is positioned at the retreat limit. The front end part 30 d ahead of d and the axial part 3 3 d in front of the axial hole 3 3 c in the BA cylindrical member 3 3 contact the vacuum valve seat member 30 and BA cylinder Both members 33 are positioned at their retracted limits.

[0040] Furthermore, a cylindrical member holding member 35 for positioning and holding the BA cylindrical member 33 in the non-operating position with respect to the valve member 4 at the time of normal brake operation is provided at a position ahead of the key member 23. Yes. This tubular member 33 for BA is inserted into the key hole 4a of the valve body 4 and the axial hole 33c of the tubular member 33 for BA, and then fitted into the radial hole 4d of the valve body 4. · It is fixed.

As shown in FIG. 5 (b), this cylindrical member holding member 35 is an elastic material and is formed in a substantially U shape from a rectangular bar having a rectangular cross section. In this case, the cylindrical member holding member 35 includes a curved annular portion 35 a through which the valve plunger 10 passes, a key hole 4 a of the nozzle body 4, and an axial hole of the BA cylindrical member 33. It consists of a pair of linear engagement parts 3 5 b and 3 5 c that penetrate 3 3 c. And the curved bottom of the bay curved ring 3 5 a 3 5 a! Is fitted and fixed in the radial hole 4 d of the valve body 4. Further, in normal times, the pair of linear engagement portions 3 5 b and 3 5 c are parallel or substantially parallel to each other.

Further, as shown in FIG. 5 (a), the BA cylindrical member 33 is provided with an engaging recess 33 f that opens in the axial hole 33 c. One of the linear engaging portions 35 b of the cylindrical member holding member 35 is normally engaged with the engaging recess 33 f. Although not shown in the figure, the BA tubular member 3 3 has another engaging recessed portion that is the same as the engaging recessed portion 3 3 f in line with the engaging recessed portion 3 3 f in the axial direction of the BA tubular member 3 3. Is provided. Then, the other linear engagement portion 35 c of the cylindrical member holding member 35 is normally engaged with the other engagement recess.

[0043] Thus, the engagement recesses (3 3 f) (the engagement recesses to which the linear engagement portions 35 c are engaged are respectively shown in the figure, where the pair of linear engagement portions 3 5 b, 3 5 c correspond to each other. Therefore, for convenience of explanation, parentheses are attached to the symbol 3 3 f on behalf of both engaging recesses. The BA tubular member 3 3, which is always urged rearward by the BA actuation spring 3 4, is not normally shown in FIGS. 1, 2 and 5 (a). It is positioned and held in the operating position. In this way, the BA cylindrical member 3 3 is normally provided by the radial hole 4 d of the valve body 4, the engagement recess (3 3 f) of the BA cylindrical member 33, and the cylindrical member holding member 3 5. Holding means for holding in the non-operating position is configured. In that case, the engaging portion of the pair of linear engaging portions 35b, 35c with the engaging recess (33f) is the holding portion of the present invention. During normal braking operation, the BA tubular member 33 is held in the non-actuated position, so that the rear end surface 3 3 e of the BA tubular member 33 is connected to the front end surface 30 of the vacuum valve seat member 30. It is prevented from coming into contact with a.

The valve plunger 10 includes an engagement recess (3 3 f) of the BA tubular member 3 3 and a pair of linear engagement portions 3 5 b and 3 5 c of the tubular member holding member 35. An unlocking portion 10a for releasing the engagement is provided. The unlocking portion 10 a is formed in a tapered shape having a frustoconical side surface. If the brake pedal is depressed more quickly than normal brake operation due to emergency brake operation, and the valve plunger 10 moves forward more than a predetermined amount with respect to the valve body 4 than during normal brake operation, this locking will occur. by releasing unit 1 0 a to press the tubular member holding member 3 at two locations of the curved annular portion 3 5 a of the edge portion 3 5 a ₂ in 5 of contact and these two places the edge section 3 5 a ₂ The curved annular portion 35 a is elastically deformed in a direction to open in a plane orthogonal to the axial direction of the BA tubular member 33. Then, the pair of linear engaging portions 35 b and 35 c is shown in FIG.

As indicated by the arrows in (b), they move away from each other in a plane perpendicular to the axial direction of the BA tubular member 33. Thus, the _two portions of the edge portion 35 a ₂ of the curved annular portion 35 a correspond to the pressed portion that is pressed by the locking release portion 10 a of the valve plunger 10.

[0045] When the pair of linear engagement portions 35b, 35c move in a direction away from each other by a predetermined amount, the linear engagement portions 35b, 35c are removed from the engagement recess (33f). It escapes and the engagement between the tubular member 33 for BA and the tubular member holding member 35 is released. As a result, the BA tubular member 33 is moved backward by the biasing force of the BA actuating spring 34. As described above, the BA tubular member 33 presses the vacuum valve seat member 30 to move the valve body 2 backward relative to the valve body 4 as described above. This rearward movement of the BA tubular member 33 ends when the front end portion 33g forward of the axial hole 30c abuts against the pair of linear engagement portions 35b, 35c. Therefore, the rearward movement amount of the valve body 2 with respect to the valve body 4 by the vacuum valve seat member 30 is limited to a fixed amount.

[0046] When the valve plunger 10 is retracted and its unlocking portion 10 0a is separated from the edge portion 3 5a ₂ of the curved annular portion 3 5a, the curved annular portion 3 5a returns to elasticity. It becomes possible. However, since the pair of linear engagement portions 35 b and 35 c remain in contact with the edges of the axial hole 33 c of the BA tubular member 33, the curved annular portion 35 a is elastically deformed. Will remain. Then, from the state where the front end portion 3 3 g of the BA tubular member 33 is in contact with the pair of linear engagement portions 35 b, 35 c, the BA tubular member 33 is in contact with the valve body 4. And move forward relatively, engaging recess

When (3 3 f) is at a position facing the corresponding pair of linear engaging portions 3 5 b, 3 5 c, the curved annular portion 3 5 a is closed in its elastic restoring force, that is, in the original shape. The pair of linear engaging portions 35 b, 35 c move in a direction approaching each other and fit into the engaging recess (33 f). In this way, the B A cylindrical member 3 is held at the initial non-operating position.

By the way, in the negative pressure booster 1 of this example, the engagement position between the pair of linear engagement portions 35 b, 3.5 c and the engagement recess (3 3 f) is the pressed portion. From the two positions of the edge portion 3 5 a ₂ of the curved annular portion 3 5 a, it is a position near the front in the axial direction.

Next, the operation of the negative pressure booster 1 of this example will be described.

(Non-operating negative pressure booster)

Negative pressure is always introduced into the constant pressure chamber 8 of the negative pressure booster 1 through the negative pressure inlet port 28. Further, in the non-operating state of the negative pressure booster 1 shown in FIGS. 1 and 2, the key member 23 abuts against the reciprocal 3 and is in a retreat limit. Therefore, the key member 2 3 limits the valve body 4 and the valve plunger 1 to the retreat limit, and further power piston 5, input shaft 1 1 and output shaft 2 6 is also the retreat limit. Further, the front end face 30a of the vacuum valve seat member 30 is brought into contact with the step 4c of the valve body 4 by the spring force of the second valve control spring 32, and the vacuum valve seat member 30 is shown in FIG. The intermediate portion 3 3 d of the BA tubular member 3 3 is in contact with the key member 2 3 by the spring force of the BA actuating spring 3 4 and the BA tubular member 3 3 is shown in FIG. Positioned as shown in. ,

[0049] In this non-operating state, the atmospheric valve portion 1 2a of the valve body 12 is seated on the atmospheric valve seat 14 and the atmospheric valve 16 is closed, and the vacuum valve portion 1 2b of the valve body 12 is The vacuum valve 1 5 is open after being separated from the vacuum valve seat 1 3. Therefore, the variable pressure chamber 9 is shielded from the atmosphere and communicates with the constant pressure chamber 8 so that a negative pressure is introduced into the variable pressure chamber 9, and a substantial differential pressure is generated between the variable pressure chamber 9 and the constant pressure chamber 8. Absent. For this reason, a force due to a pressure difference is not applied to the vacuum valve seat member 30 backward.

In addition, the BA mechanism 36 has a pair of linear engagement portions 35 b and 35 c engaged with the engagement recess (33 f) of the BA tubular member 33 and held in the non-operating position. Yes.

[0050] (Negative pressure booster setting input F. Normal brake operation ¾j in the following input area) When the brake pedal is depressed at the normal brake operation speed to perform normal braking, input Axis 1 1 moves forward and valve plunger 1 0 moves forward. As the valve plunger 1 0 moves forward, the vacuum valve section 1 2 b of the valve body 1 2 is seated on the vacuum valve seat 1 3, the vacuum valve 1 5 is closed, and the atmospheric valve seat 1 4 is the atmospheric valve of the valve body 1 2. Apart from part 1 2 a, atmospheric valve 16 opens. That is, the variable pressure chamber 9 is disconnected from the constant pressure chamber 8 and communicated with the atmosphere. Therefore, atmospheric pressure air is transformed through the air inlet 20 0a, outer peripheral passage 19a, inner peripheral passage 19b, open atmospheric valve 16 and keyhole 4a. Introduced into Chamber 9. As a result, a differential pressure is generated between the variable pressure chamber 9 and the constant pressure chamber 8, the power piston 5 moves forward, the output shaft 26 advances further through the valve body 4, and the piston of the mass cylinder (not shown) moves forward. To do. At this time, the members supported by the valve body 4 such as the valve body 12, the vacuum valve seat member 30, and the BA tubular member 33 move together with the valve body 4.

[0051] Further, when the valve plunger 10 advances, the spacing member 2 4 also advances. The spacing member 24 does not reach the reaction disk 25 due to the gap C. Accordingly, since the reaction force is not transmitted from the reaction disk 25 to the spacing member 24 from the output shaft 26, this reaction force is not transmitted to the brake pedal via the valve plunger 10 and the input shaft 11. When the input shaft 11 further advances, the power piston 5 further advances, and the piston of the mass cylinder further advances through the valve body 4 and the output shaft 26.

[0052] When the loss stroke of the brake system after the mass cylinder disappears, the negative pressure booster 1 substantially generates an output, and the mass cylinder generates the mass cylinder pressure (hydraulic pressure) with this output. The wheel cylinder operates with this mass cylinder pressure to generate braking force.

At this time, the reaction disk 25 bulges back by the reaction force applied to the output shaft 26 from the mass cylinder, the gap C disappears, and the reaction disk 25 abuts against the spacing member 24. . As a result, the reaction force from the output shaft 26 is transmitted from the reaction disk 25 to the spacing member 24, and further transmitted to the brake pedal via the valve plunger 10 and the input shaft 11 to sense the driver. Will come to be. That is, as shown in FIG. 4, the negative pressure booster 1 exhibits a jumping characteristic having a jumping amount J s during normal braking operation.

[0054] Setting input F. When the normal brake is operated with the following inputs, the output of the negative booster 1 (that is, the pedal depression force) is relatively small, so the output is in the output range below the predetermined output. Therefore, as described above, the pressure PV in the variable pressure chamber 9 and the pressure P v in the constant pressure chamber 8. Differential pressure by the force F _P that presses the vacuum valve seat member 3 0 is smaller than the sum of the first and second valve control spring 1 8, 3 each spring forces of the second and.

For this reason, the vacuum valve seat member 30 does not move backward with respect to the valve body 4 and the servo ratio becomes a comparatively small servo ratio that is substantially the same as that in the conventional normal brake operation. Therefore, when the output of the negative pressure booster 1 becomes the magnitude obtained by boosting the input of the input shaft 1 1 by the pedal depression force with this small servo ratio SR i, the large air valve section 1 2 a becomes the atmospheric valve seat 1 4 is closed and the atmospheric valve 1 6 is also closed to achieve a balance state with an intermediate load. (Vacuum valve 1 5 has vacuum valve section 1 2 b attached to vacuum valve seat 1 3. Sitting and already closed). Thus, as shown in Fig. 4, in the input area below the set input F'Q, the normal brake is operated with the brake force that is boosted by the servo ratio SR.

[0056] Further, when the brake pedal is depressed at the depression speed at the time of normal brake operation, even if the valve plunger 10 moves forward, the unlocking portion 10 0a is not in the cylindrical member holding member 35. It does not come into contact with the edge 3 5 a ₂ of the curved bottom 3 5 a! Of the curved annular part 3 5 a. Therefore, the BA mechanism 36 does not operate.

[0057] When the brake pedal is released to release the normal brake from the state where the atmospheric valve 1 6 and the vacuum valve 1 5 of the negative pressure booster 1 are both closed during normal brake operation, the input shaft 1 1 and the valve plunger 10 both move backward, but the valve body 4 and the vacuum valve seat member 30 do not move immediately because air (atmosphere) is introduced into the variable pressure chamber 9. As a result, the atmospheric valve seat 14 of the solenoid plunger 10 presses the atmospheric valve portion 1 2 a of the valve body 1 2 backward, so the vacuum valve portion 1 2 b is separated from the vacuum valve seat 13 g. Sit down and vacuum valve 1 5 opens. Then, since the variable pressure chamber 9 communicates with the constant pressure chamber 8 via the open vacuum valve 15 and the vacuum passage 22, the air introduced into the variable pressure chamber 9 is opened with the open vacuum valve 15, the vacuum passage 22, It is discharged to the vacuum source through the constant pressure chamber 8 and the negative pressure inlet 2 8.

[0058] As a result, the pressure in the variable pressure chamber 9 becomes low and the differential pressure between the variable pressure chamber 9 and the constant pressure chamber 8 becomes small. Therefore, the spring force of the return spring 2 7 causes the power piston 5, the valve body 4 and the output shaft. 2 6 moves backward. As the valve body 4 moves backward, the spring force of the return spring of the piston of the mass cylinder also retracts the piston of the mass cylinder and the output shaft 26, and the normal brake starts to be released.

[0059] When the key member 2 3 comes into contact with the rear shell 3 as shown in FIGS. 1 and 2, the key member 23 stops and does not retract further. However, the valve body 4, the valve plunger 10 and the input shaft 1 1 are further retracted. Then, the valve plunger 10 abuts against the key member 23 and does not move any further, and further, the front end 4 a of the key hole 4 a of the valve body 4 a! Is the key member 2 3 In contact with it, the valve body 4 will not retract any further. Thus, the negative pressure booster 1 is in the initial inoperative state shown in FIGS. Accordingly, the mass cylinder is deactivated and the mass cylinder pressure disappears, and the wheel cylinder is deactivated and the brake force disappears, so that the normal brake is released.

(Negative pressure booster setting input F. During normal brake operation in a larger input range)

Normal brake pedal depression speed during normal brake operation and negative pressure booster 1 setting input F. When normal braking is performed in a larger input range, if the input of the negative pressure booster 1 (that is, corresponding to the pedal depression force) increases, the output becomes an output range larger than the predetermined output, and The pressure P v in chamber 9 also increases.

Setting input F. In the larger input area, the pressure PV in the variable pressure chamber 9 and the pressure P v in the constant pressure chamber 8. Since the force F _P that presses the vacuum valve seat member 3 0 is greater than the sum of the first and second valve control spring 1 8, 3 each spring force of 2 due to the pressure difference between, vacuum valve seat member 3 0 The first and second valve control springs 1 8 and 3 2 are contracted and moved backward with respect to the valve body 4 while pushing the valve body 1 2. For this reason, the atmospheric valve section 1 2 a is farther away from the atmospheric valve seat 14 than usual, and the atmospheric valve 16 opens greatly. Therefore, as shown in FIG. 4, in this large input area, the servo ratio SR ₂ is larger than the servo ratio SR! As described above. That is, when the output of the negative pressure booster 1 becomes the magnitude obtained by boosting the input of the input shaft 11 with this large servo ratio SR ₂ , the atmospheric valve section 1 2 a is connected to the atmospheric valve seat 14 as described above. Sit down and close atmospheric valve 1 6 and control valve 17 becomes balance position of intermediate load (Vacuum valve 1 5 is already closed with vacuum valve section 1 2 b seated on vacuum valve seat 1 3 )

Therefore, the balance position of the control valve 17 moves backward. Thus, in such a large input area, the brake is operated by boosting the large braking force to the pedal effort in a large Sapo ratio SR _2. In that case, the negative pressure booster 1 has a large pedal input force, that is, the input of the negative pressure booster 1 is large in this large input region. However, with the same input as when normal brake is operating with small servo ratio SR!, A larger output can be obtained than when normal brake is operating.

[0063] Further, when the large input area is operated, the vacuum valve seat member 30 is moved backward by the stroke amount with respect to the valve body 4 than when the vacuum valve seat member 30 is operated in the small input area (setting input F, the following input area). Since it moves, the output stroke increases according to the amount of stroke. That is, the stroke of the input shaft 11, that is, the stroke of the brake pedal is shortened. In addition, the input port of this input shaft 1 1

The details of the shortening are disclosed in International Publication No. 2 0 0 4-1 0 1 3 4 0 and can be understood by referring to this publication.

[0064] When the vacuum valve seat member 30 is activated, the brake pedal is released to release the normal brake from the state that both the atmospheric valve 1 6 and the vacuum valve 15 of the vacuum booster 1 are closed. Then, the vacuum valve 15 opens as in the case of normal brake operation in the low input region described above, and the air introduced into the variable pressure chamber 9 opens the vacuum valve 15, the vacuum passage 2 2, the constant pressure chamber. 8 and negative pressure inlet 2 8 are discharged to a vacuum source.

[0065] As a result, the pressure in the variable pressure chamber 9 decreases as described above, and the power piston 5, valve body 4, and output shaft are driven by the spring force of the return spring 27.

2 6 moves backward. As the valve body 4 moves backward, the piston of the mass cylinder and the output shaft 26 move backward due to the spring force of the return spring of the mass cylinder cylinder, and the brake starts to be released.

[0066] As the differential pressure between the variable pressure chamber 9 and the constant pressure chamber 8 becomes small, the force Fp that presses the vacuum valve seat member 30 is the pressure PV of the variable pressure chamber 9 is the first and second valve control springs 18,

When the spring load F s, f _s of 3 2 becomes smaller, the vacuum valve seat member 30 moves relatively forward with respect to the valve body 4, and the vacuum valve seat member 30 becomes non-shown in FIG. Becomes working position. As a result, the vacuum valve section 1 2 b is greatly separated from the vacuum valve seat 1 3 g and the vacuum valve 15 opens widely, so that a large amount of air in the variable pressure chamber 9 is exhausted, The brake is activated. From this point on, it is the same as in the case of normal brake operation in the small input area described above. Finally, all the moved members of the negative pressure booster 1 are in the non-operating position shown in FIG. Rake is released.

[0067] During the return process of the vacuum valve seat member 30 to the non-operating position (the forward movement of the vacuum valve seat member 30 with respect to the valve body 4), the vacuum valve seat member 30 raises a stick to control the second valve. When the spring force of the spring 3 2 stops moving forward, the key body 2 3 that does not move backward due to contact with the rear shell 3 3 0 e force due to the backward movement of the valve body 4 Abut. Therefore, the vacuum valve seat member 30 is also prevented from moving backward. However, when the valve body 4 is further moved backward, the vacuum valve seat member 30 that raises the stick is forcibly moved forward with respect to the valve body 4. For this reason, the vacuum valve seat member 30 is surely brought into the inoperative position shown in FIG. 2 and the vacuum valve is opened, and the negative pressure booster 1 is surely brought into the inoperative position, and the brake is released.

[0068] (At the time of B A operation of negative pressure booster)

If the brake pedal is depressed at a higher depressing speed than during normal braking and an emergency braking operation is performed, the forward movement of the input shaft 11 and the valve plunger 10 relative to the valve body 4 will increase. Then, the unlocking portion 10 0 a of the valve plunger 10 is in contact with the edge portion 3 5 a ₂ of the cylindrical member holding member 35 5 to push open the cylindrical member holding member 35. The engagement between the pair of linear engaging portions 35 b, 35 c of the member holding member 35 and the engaging recess (33 f) of the BA tubular member 33 is released.

Then, as described above, the BA tubular member 3 3 moves backward by a predetermined amount with respect to the valve body 4 while pressing the vacuum valve seat member 30 backward by the biasing force of the BA actuating spring 3 4. Therefore, the vacuum valve seat member 30 and the valve body 12 also move backward by a predetermined amount and stop.

[0070] At this time, the pedal depression force, that is, the input of the negative pressure booster 1 is the setting input F. In the following small input area, the servo ratio of the negative pressure booster 1 becomes the small servo ratio SR i. The reaction disk 25 is not yet in contact with the spacing member 24, but when the reaction disk 25 expands and contacts the spacing member 24 due to the reaction force from the output shaft 26, negative pressure Booster 1 output increases. Therefore, as shown in Fig. 4, the jamming characteristic during BA operation Jumbing amount J e becomes larger than the amount of shampooing J s during normal brake operation (J e> J s). As a result, a large braking force is generated with a small pedal effort.

[0071] In the same manner as in the normal brake operation described above, a balanced state is obtained with an intermediate load in which both the vacuum valve 15 and the atmospheric valve 16 are closed. The balance position of the vacuum valve 15 and atmospheric valve 16 at this time is the setting input F described above. The vacuum valve seat member 30 and the valve body 12 move backward by a predetermined amount from the normal brake operation in the following small input area. Thus, as shown by the two-dot chain line in Fig. 4, set input F. In the following small input areas, the emergency brake is operated with the brake force that is boosted by the small ratio S R of the pedal depression force when the emergency brake is activated and increased by the large amount of jerk Je. Further, since the balance position where both the atmospheric valve 16 and the vacuum valve 15 are closed moves backward, the stroke of the input shaft 11 is shortened accordingly, and as a result, the pedal stroke is shortened. In this way, a large braking force is generated with a small pedal effort and a small pedal stroke. In this way, BA operation is performed during emergency braking operation.

[0072] Also, when the brake pedal is stepped on at a faster stepping speed than during normal braking, the input of negative pressure booster 1 is the setting input F. If the input area is larger, the setting input F mentioned above. As in the case of BA operation in the following small input area, the BA tubular member 33 moves to a predetermined amount rearward with respect to the valve body 4 and stops, so the vacuum valve seat member 30 and the valve The body 12 also moves a predetermined amount backward with respect to the valve body 4 and stops.

[0073] And setting input F. In the larger large input region, the pressure P v in the variable pressure chamber 9 and the pressure P v in the constant pressure chamber 8 are the same as in the case of normal braking operation in the large input region larger than the set input F o described above. Differential pressure by the force F _P that presses down the vacuum valve seat member 3 0 is greater than the sum of the first and second valve control spring 1 8, 3 each spring force of 2, the vacuum valve seat member 3 0 and valves with Body 1 2 moves backward relative to valve body 4. For this reason, the atmospheric valve 16 opens further. Therefore, as shown by the two-dot chain line in Fig. 4, Thus, the servo ratio SR ₂ is larger than the servo ratio SR!. Therefore, the emergency brake is activated with a larger braking force by the BA operation.

[0074] (When negative pressure booster B A operation is released)

Setting input F. When the brake pedal is released after the BA operation in the following small input area, the valve body 4, power piston 5, valve plunger 1 0, input shaft 1 1, output shaft 2 6 etc. are retracted and the normal brake operation described above is performed. Return to the non-operating position shown in Fig. 1 and Fig. 2 in the same way as the release of. In that case, since the unlocking portion 10 0 a of the valve plunger 10 is separated from the edge portion 3 5 a _{2 of} the cylindrical member holding member 3 5, the pair of linear engagement portions 3 of the cylindrical member holding member 3 5 5 b, 35 c become engageable with the engaging recess (33 f) of the BA tubular member 33. On the other hand, the BA tubular member 33 is brought into contact with the non-removing member 23, where the intermediate portion 3 3 d of the BA tubular member 33 is brought into contact with the reciprocal 3 by the backward movement of the valve body 4. . Therefore, the BA tubular member 33 is also prevented from moving backward. However, when the valve body 4 is further moved backward, the BA tubular member 33 is forcibly moved forward with respect to the valve body 4 by the key member 23 and returned to the inoperative position. As a result, the pair of linear engaging portions 3 5 b, 3 5 c are engaged with the engaging recesses (3 3 f) of the BA tubular member 33 by the elastic restoring force of the tubular member holding member 35, The BA tubular member 33 is held in the non-operating position.

[0075] Also, setting input F. When the brake pedal is released after BA operation in a larger large input area, normal brake operation in the input area larger than the above-mentioned set input F and emergency brake operation in the small input area below the above-mentioned set input F The emergency brake is released in the same way as when releasing.

[0076] According to the negative pressure booster 1 of this example applied to the brake system in this way, the tubular member holding member 35 is provided separately from the BA tubular member 33, and a pair of The positions of the engagement between the straight engagement portions 3 5 b, 3 5 c and the engagement recess (3 3 f) at the two positions of the edge portions 3 5 a ₂ of the curved annular portion 3 5 a which is the pressed portion Therefore, the holding means can be shortened in the axial direction, and the BA mechanism 36 can be made compact and compact accordingly. [0077] Also, since the curved annular portion 35a of the tubular member holding member 35 is elastically deformed in a plane perpendicular to the axial direction of the BA tubular member 33, the holding The means can be further shortened in the axial direction, and accordingly, the eight-eight mechanism 3 6 can be more effectively formed into a compact body.

[0078] Further, since the cylindrical member holding member 35 is elastically deformed, it is not necessary to elastically deform the BA cylindrical member 33, and the BA cylindrical member 33 is provided with a cylindrical member. The BA tubular member 33 can have a simpler structure by simply forming an engaging recess having a simple shape with which the holding member 35 is engaged. Moreover, since the BA tubular member 3 3 is configured separately from the vacuum valve seat member 30, there is no need to provide a vacuum valve seat on the BA tubular member 3 3, and the BA tubular member 3 3 Can be made simpler.

[0079] Further, since the cylindrical member holding member 35 is formed of a square bar made of an elastic material formed in a U shape, it can be formed into a more compact and simpler structure. .

In this way, according to the negative pressure booster 1 of this example, the B A mechanism 36 can be made compact and compact with a simple structure.

FIG. 6 is a partially enlarged sectional view similar to FIG. 2, showing another example of the embodiment of the negative pressure booster according to the present invention. The same components as those in the previous example are denoted by the same reference numerals, and detailed description thereof is omitted.

In the BA mechanism 36 of the above example, the cylindrical member holding member 35 is disposed in front of the key member 23. However, in the BA mechanism 36 of the negative pressure booster 1 of this example, As shown in FIG. 6, a cylindrical member holding member 35 is arranged behind the key member 23. In that case, the pair of linear engaging portions 35 b, 35 c of the cylindrical member holding member 35 does not extend to the valve body 4, and extends only to the B A cylindrical member 35.

[0081] Further, the BA tubular member 33 is formed with a step portion 33h for defining the amount of transfer. The amount of movement when the BA tubular member 33 moves relative to the valve body 4 backward is defined as a predetermined amount. Furthermore, the unlocking portion 10 0 a of the valve plunger 10 is connected to the atmospheric valve seat 14 of the valve plunger 10 and the valve The valve plunger 10 is provided between the plunger 10 and the connecting portion of the input shaft 14.

Thus, in the BA mechanism 36 of this example, since the cylindrical member holding member 35 is disposed behind the partial member 23, the cylindrical member holding member 35 is connected to the atmospheric valve. It can be efficiently arranged in the dead space portion of the valve plunger 10 between the seat 14 and the connecting portion between the valve plunger 10 and the input shaft 14. Therefore, the B A mechanism 36 can be further shortened in the axial direction, and more effectively formed into a compact compact cage.

Other configurations and other functions and effects of the negative pressure booster 1 in this example are the same as those in the above example.

In the above-described example, the cylindrical member holding member 35 is formed in a U shape, but the cylindrical member holding member 35 is an unlocking portion 10 0 a of the valve plunger 10. Any shape can be used as long as it can be elastically deformed in a plane perpendicular to the axial direction of the BA tubular member 33 when pressed by.

[0084] In the above example, the vacuum valve seat member 30 is provided, but the vacuum valve seat member 30 is not always necessary and can be omitted. In that case, the BA tubular member 33 is provided with a vacuum valve seat 13 on which the vacuum valve portion 1 2 b can be seated, and the vacuum valve seat 13 is attached to the valve body 4 by holding means when the BA is not operating. In contrast, when the BA is activated, the holding means is released, the vacuum valve seat 13 is moved relative to the valve body 4 by a predetermined amount, and then the valve body 4 is stopped. In this case, the servo ratio of the negative pressure booster 1 is only the small servo ratio S R.

Furthermore, in the above example, the operation of the vacuum valve seat member 30 is controlled by the pressure difference between the pressure in the variable pressure chamber 9 and the pressure in the constant pressure chamber, but the present invention is not limited to this. The operation of the vacuum valve seat member 30 can be controlled only by the pressure in the variable pressure chamber 9 or the pressure difference between the pressure in the variable pressure chamber 9 and another constant pressure. Furthermore, the operation of the vacuum valve seat member 30 can be controlled by a pressure corresponding to the input applied to the input shaft 11 instead of the pressure in the variable pressure chamber 9.

[0086] Further, in the above-described example, the present invention is applied to a single power piston 5 The present invention is also applicable to a tandem negative pressure booster having a plurality of power pistons 5.

Furthermore, in the above-described example, the negative pressure booster of the present invention is applied to the brake system, but it can be applied to other systems and devices that use the negative pressure booster.

Industrial applicability

The negative pressure booster according to the present invention can be used for a negative pressure booster used in a brake booster or the like. In particular, when an emergency brake is operated, the same input (brake operating force) as that during normal operation is used. It can be suitably used for a negative pressure booster capable of obtaining a larger output than that during normal operation.

Claims

The scope of the claims

1. A valve body that is disposed so as to be movable back and forth with respect to the inside of the shell, a constant pressure chamber that is provided in the valve body and into which negative pressure is introduced, and a variable pressure chamber into which air is introduced during operation. A partitioning power piston, a valve plunger connected to the input shaft and slidably disposed in the valve body, and a valve body and a vacuum valve seat on which the valve body can be seated and separated, A vacuum valve that controls communication or blocking between the constant pressure chamber and the variable pressure chamber by the operation of the valve plunger; and the valve body and an atmospheric valve seat on which the valve body can be seated and separated. An atmospheric valve that shuts off or controls communication between the variable pressure chamber and at least the atmosphere by the operation of the plunger, and operates when the input shaft is moved faster than the movement speed during normal operation to output more than normal. If you increase the operation assist mechanism to increase, In the negative pressure booster which is equipped,

The atmospheric valve has an atmospheric valve part that is provided on the valve body and can be separated from and seated on the atmospheric valve seat,

The vacuum valve has a vacuum valve portion that is provided on the valve body and can be separated from and seated on the vacuum valve seat,

The vacuum valve seat is provided so as to be movable relative to the valve body, and the vacuum valve portion and the atmospheric valve portion are movable to the body,

The operation assist mechanism includes: a cylindrical member that moves the vacuum valve portion and the atmospheric valve portion rearward with respect to the valve body by a predetermined amount via the vacuum valve seat during operation; A cylindrical member holding member that is held in an operating position, and the cylindrical member is slidably provided on the valve body and is always urged rearwardly,

The cylindrical member holding member is pressed by the valve plunger when the input shaft is moved faster than the moving speed during normal operation, so that the cylindrical member holding member is in a plane perpendicular to the axial direction of the cylindrical member or the cylinder. A negative pressure booster characterized in that the cylinder member is elastically deformed in a plane substantially orthogonal to the axial direction of the cylindrical member to release the non-operating position of the cylindrical member.

2. A valve body arranged to be able to move forward and backward with respect to the inside of the shell, a constant pressure chamber provided in the valve body, into which negative pressure is introduced, and air is introduced during operation. A power piston partitioned into a variable pressure chamber, a valve plunger connected to the input shaft and slidably disposed in the valve body, a valve body and a vacuum valve seat on which the valve body can be seated and separated A vacuum valve that controls communication or blocking between the constant pressure chamber and the variable pressure chamber by operation of the valve plunger, and an atmospheric valve seat on which the valve body and the valve body can be seated and separated. And an atmospheric valve that controls or communicates at least between the variable pressure chamber and the atmosphere by the operation of the valve plunger, and operates when the input shaft is moved faster than the moving speed during normal operation. In a negative pressure booster equipped with at least an operation assist mechanism that makes the output larger than normal,

The actuation assist mechanism includes a tubular member that moves the vacuum valve portion and the atmospheric valve portion backward by a predetermined amount with respect to the valve body via the vacuum valve seat during operation, and the tubular member during normal operation. A cylindrical member holding member that is held in a non-operating position, and the cylindrical member is slidably provided on the valve body and is always urged rearwardly,

The cylindrical member holding member is elastically deformed by being pressed by the valve plunger when the input shaft is moved faster than the moving speed during normal operation, and releases the holding of the non-operating position of the cylindrical member. And

Further, the pressed portion of the cylindrical member holding member pressed by the valve blanker and the holding portion of the cylindrical member in the cylindrical member holding member are provided at a position near the axial direction of the cylindrical member. A negative pressure booster characterized by that.

3. The cylindrical member holding member is made of a U-shaped elastic rod member, and the rod member is in a plane perpendicular to the axial direction of the cylindrical member or the axial direction of the cylindrical member. 3. The negative pressure booster according to claim 1, wherein the cylindrical member is elastically deformed in a substantially orthogonal plane to release the non-operating position of the cylindrical member.