CN201472361U - Mechanical vacuum booster with emergency braking function - Google Patents

Abstract

The utility model relates to a mechanical vacuum booster with an emergency braking function, belonging to the field of automobile brake. The mechanical vacuum booster comprises a control valve assembly that comprises a valve body, an input rod, a sieve spring base, a conical spring, a spring base, a compression spring, a vacuum leather cup, a trigger mechanism, a trigger mechanism spring, a plunger, a lock blade, a lock blade spring, a valve block, a proportion disc, a reaction disc, an output rod, an elastic retaining ring, a rubber sealing ring, a rear shell, a diaphragm, a diaphragm disc, a front shell, a large-return spring, and the like. The mechanical vacuum booster has the advantages that the structure is novel, the cost is low, when the driver applies emergency braking, as long as certain input power requirement is met, the vacuum booster outputs large force to a main braking cylinder and keeps the output pressure on the main cylinder even when the input force is reduced, thus shortening the braking distance of the whole vehicle, thereby being particularly effective for amateurish drivers and braking hesitators.

Description

A kind of mechanical vacuum booster with emergency braking function

Technical field

The utility model relates to a kind of vacuum booster, more specifically, relate to a kind of like this vacuum booster: this vacuum booster can be guaranteed under the situation of certain horsepower input under the emergency braking situation, and obtain the power output of an increasing, and obtain pressure and keep.

Background technology

Vacuum booster is the critical component in the brake system of car, and its effect is that the vacuum of utilizing engine intake manifold vacuum or aux. vacuum pump to produce is amplified brake pedal force, thereby alleviates the power that chaufeur is used to brake.The cardinal principle of vacuum booster is that servo-unit has former and later two epitrochoidal chambers, thereby two epitrochoidal chambers produce the effect of draught head realization power-assisted when servo-unit is worked, and two epitrochoidal chambers separate by valve body, diaphragm dish, diaphragm.

Conventional vacuum booster is when the chaufeur apply the emergency brake, and chaufeur only applies under the situation of less treadle effort, can not increase the power-assisted effect of vacuum booster rapidly, thereby makes the braking effect of car load not obvious.In addition, conventional vacuum booster needs chaufeur to apply bigger treadle effort and keeps a period of time when apply the emergency brake, so that braking rapidly, this is a test to small and weak or unskilled river, and it is tired that chaufeur is produced.

The utility model content

The utility model provides a kind of mechanical vacuum booster with emergency braking function, when carrying out emergency braking, need chaufeur to apply bigger treadle effort and the difficult shortcoming that keeps of required treadle effort to solve conventional vacuum booster, guarantee the sufficient power-assisted effect that has of vacuum booster, thereby guarantee the braking effect of car load.

The technical scheme that the utility model is taked is as follows:

A kind of mechanical vacuum booster with emergency braking function, its control valve assembly comprises valve body, the input bar, the filter screen spring perch, cone-shaped spring, spring perch, compression spring, the vacuum leather cup, trigger mechanism, the trigger mechanism spring, plunger, locking plate, the locking plate spring, the valve piece, the ratio dish, reaction plate, take-off lever, circlip and rubber seal, described input bar passes the filter screen spring perch successively, cone-shaped spring, spring perch, compression spring, the vacuum leather cup, its bulb partly stretches in the plunger counterbore, input bar and plunger link together by riveted joint, but the input bar can rotate relative to plunger, step on the described input bar is pressed in that the contact left-hand thread connects on the step of filter screen spring perch inwall, described spring perch is pressed on the first boss upper surface in the valve body, cone-shaped spring is between filter screen spring perch and spring perch, described vacuum leather cup one end has internal buckle ring to be positioned at valve body first boss inboard and is buckled in the circular groove of spring perch lower end, the other end end face of vacuum leather cup is connected with second boss contact in the valve body, forms vacuum valve between second boss in the end face of described vacuum leather cup and the valve body; It is characterized in that: described trigger mechanism is made up of two parts: outer wall have a plurality of free air diffusers, inwall have step cylindrical portions may and with the spring leaf of a plurality of symmetric arrangement of cylindrical portions may bonded assembly, the spring leaf centre portion has inwardly protruded boss, described boss both sides all have domatic, and the spring leaf end has hook; Described trigger mechanism, its cylindrical portions may is set in the plunger outside, has step to be buckled on the interior step of cylindrical portions may on the plunger outer wall, and its upper surface and vacuum leather cup were fitted when cylindrical portions may moved up; Between plunger outer wall and trigger mechanism cylindrical portions may inwall, set up rubber seal, seal; Described trigger mechanism spring one end withstands on interior the 3rd boss of valve body, and the other end withstands on the trigger mechanism cylindrical portions may end face, makes trigger mechanism that the trend of moving behind the relative valve body be arranged; Described plunger centre portion outer wall has annular groove, locking plate is a U-shaped, locking plate passes the radially slotted eye in the valve body, and be enclosed within on the annular groove of plunger outer wall, locking plate can move along plunger is upper and lower in the radially slotted eye in valve body, described locking plate spring housing is contained in the plunger outside, and an end contacts with the 4th raised head face in the valve body, and the other end withstands on the locking plate centre portion end face; When the servo-unit initial condition, described locking plate centre portion contacts with the boss of trigger mechanism spring leaf centre portion, and spring leaf is outwards opened; On the described valve piece outer wall step and groove are arranged, the valve piece contacts with the interior round boss end face of valve end by the step surface on the outer wall, and valve piece step outer wall and described in set up rubber seal between the round boss inner hole wall, the forward and backward epitrochoidal chamber of servo-unit is isolated; Described take-off lever one end has circular groove, is placed with reaction plate in the circular groove, and described reaction plate top is placed with the valve piece; On the groove on the described valve piece outer wall annular edge edge is arranged, the terminal hook of described trigger mechanism spring leaf can hang over when servo-unit is implemented emergency braking on the described annular edge edge; Have through hole in the described valve piece, the throughhole portions that external diameter is big is placed the ratio dish.

On the basis of conventional vacuum booster, parts such as trigger mechanism, valve piece, two compression springs and rubber seal have been increased, in initial condition or normal brake application operating process, the terminal hook of described trigger mechanism spring leaf is not hooked by the edge of the annular edge on the described valve piece, under the effect of trigger mechanism spring, trigger mechanism cylindrical portions may top has formed first air valve mouth to vacuum leather cup end face; In the emergency brake operations process, when trigger mechanism is driven forwards certain stroke with respect to valve body, the terminal hook of described trigger mechanism spring leaf is hooked by the edge of the annular edge on the valve piece, before this state is not disengaged, plunger will form second largest air valve mouth with the vacuum leather cup, and second largest air valve mouth will use as the atmosphere valve in the emergency braking releasing process.

In the emergency braking dispose procedure, along with vacuum valve is return and opened to the relative valve body of plunger, pressure reduction between the forward and backward epitrochoidal chamber rapidly disappears, valve body is under the effect of big pull back spring, rollback is to initial position, thereby locking plate touches back cover and is forced to the reach of relative valve body by rear housing is spacing, this moment, trigger mechanism spring leaf inner convex platform can be by locking plate jack-up, thereby make the annular edge edge on the terminal hook disengaging of the trigger mechanism spring leaf valve piece, under the effect of trigger mechanism compression spring, transfer from one place to another under escort lock behind the relative valve body of trigger mechanism, come back to incipient state.

Trigger mechanism is sleeved on the outside of plunger, and sets up rubber seal between plunger and trigger mechanism, plays the static seal effect, with epitrochoidal chamber behind the servo-unit and atmospheric isolation.

Between locking plate and valve body, set up a locking plate spring, its effect is: after locking plate leaves rear housing, this locking plate spring can promote to move behind the relative valve body of locking plate, thereby make the inwardly protruded boss at trigger mechanism spring leaf middle part leave locking plate, described spring leaf is released, for the locking and the release of trigger mechanism are prepared.

In normal brake application and emergency braking excitation process, trigger mechanism is with the same moved further of plunger, and in emergency braking and maintenance process, trigger mechanism can be moved behind the valve body relatively by valve piece locking, and plunger can order about mobile easily.In the normal brake application operating process, the atmosphere valve of the first air valve mouth that trigger mechanism and vacuum leather cup form during as the control valve assembly normal brake application uses, and servo-unit will be exported normal characteristic curve; In the emergency brake operations process, when trigger mechanism is driven forwards certain stroke with respect to valve body, the terminal hook of trigger mechanism spring leaf can be by valve piece annular edge along hooking, trigger mechanism is by locking, plunger will form second largest air valve mouth with the vacuum leather cup, and second largest air valve mouth will use as the atmosphere valve in the emergency braking releasing process.When trigger mechanism during by locking, first air valve mouth is opened by force and is held, and vacuum booster can respond and produce bigger power output fast, promptly produces a high jumping increment, thereby realizes that fast run-up presses, and reaches the purpose of rapid braking; Chaufeur only need apply less treadle effort just can maintain the state that this fast run-up is pressed, and both just can realize with less input force that pressure kept; The requirement that pressure keeps in the emergency braking process is satisfied in the unlatching of sluggish vacuum valve.

The utility model advantage is: novel structure, with low cost, chaufeur is when apply the emergency brake, as long as satisfy certain horsepower input requirement, vacuum booster can be exported bigger application force to master brake cylinder, and under the situation that input force reduces, pressure is kept, thereby shorten the stopping distance of car load, especially particularly effective to unskilled river and the braking person of hesitating.

Description of drawings

Fig. 1 is the utility model vacuum booster assembly incipient state revolved sectional view;

Fig. 2 is the utility model control valve assembly parts exploded drawingss;

Fig. 3 is the utility model valve body and control valve assembly partly cut-away 3-D view;

(a), valve body is cut 3-D view open; (b), control valve assembly partly cut-away 3-D view;

Fig. 4 is the utility model trigger mechanism 3-D view and section-drawing;

(a), 3-D view; (b), section-drawing;

Fig. 5 is the utility model valve piece 3-D view and section-drawing;

(a), 3-D view; (b), section-drawing;

Fig. 6 is the utility model plunger 3-D view and section-drawing;

(a), 3-D view; (b), section-drawing;

Fig. 7, the 8th, the utility model incipient state control valve assembly revolved sectional view;

Fig. 9 the utility model normal brake application mode control valve assembly revolved sectional view;

Figure 10 is the utility model emergency braking condition control valve assembly revolved sectional view;

Figure 11 is the utility model emergency braking hold mode control valve assembly revolved sectional view;

Figure 12 is the utility model emergency braking release position control valve assembly revolved sectional view;

Figure 13 is ideally input-output characteristic curve during different conditions of the utility model vacuum booster.

The specific embodiment:

All label declarations in the accompanying drawing:

1-imports bar, step on the 1a-input bar, the 2-inner filter core, the 3-cone-shaped spring, 4-spring perch, 5-compression spring, 6-vacuum leather cup, the end face of 6a-vacuum leather cup bottom, the internal buckle ring on the 6b-vacuum leather cup, 7-plunger, 7a-plunger outer lug boss, 7b-plunger outer wall first step face, 7c-plunger outer wall second step face, 7d-plunger outer wall annular groove left side, 7e-plunger outer wall annular groove right side, 7f-plunger head end face, 8-trigger mechanism spring, 9-locking plate, right side, 9a-locking plate middle part, 9b-locking plate end end face, left side, 9c-locking plate middle part, 10-rubber seal, 11-valve piece, step surface on the 11a-valve piece outer wall, the annular edge edge on the 11b-valve piece outer wall groove, step surface in the 11c-valve piece, 12-ratio dish, 12a-ratio dish end face, 12b-ratio dish step surface, 13-reaction plate, the 14-take-off lever, the 15-circlip, 16-locking plate spring, 17-trigger mechanism, 17a-trigger mechanism outer lug boss, step surface in the 17b-trigger mechanism, the outer step surface of 17c-trigger mechanism, the inner convex platform on the 17d-trigger mechanism spring leaf, the terminal hook of 17e-trigger mechanism spring leaf, the 18-rubber seal, first boss in the 19-valve body, 19a-valve body, second boss in the 19b-valve body, the 4th boss in the 3rd boss in the 19c-valve body, 19d-valve body, the 19e-valve block internal diameter is to the slotted eye left side, the 19f-valve block internal diameter is to the slotted eye right side, the interior round boss of 19g-valve end, 20-filter screen spring perch, the step on the 20a-filter screen spring perch inwall, the 21-rear housing, step surface in the 21a-rear housing, epitrochoidal chamber behind the 22-, 23-diaphragm, 24-diaphragm dish, epitrochoidal chamber before the 25-front case, 26-, the big pull back spring of 27-.

As shown in Figure 1, 2, the vacuum booster assembly with emergency braking function comprises parts such as input bar 1, filter screen spring perch 20, inner filter core 2, cone-shaped spring 3, spring perch 4, compression spring 5, vacuum leather cup 6, plunger 7, trigger mechanism 17, seal ring 18, trigger mechanism spring 8, locking plate 9, locking plate spring 16, rubber seal 10, valve piece 11, ratio dish 12, reaction plate 13, take-off lever 14, circlip 15, valve body 19, rear housing 21, diaphragm 23, diaphragm dish 24, front case 25 and big pull back spring 27.Rivet between diaphragm dish 24 and the valve body 19 and be connected, diaphragm 23 is enclosed within on the diaphragm dish, diaphragm 23 interstitial holes are connected with valve body 19 interference contact, diaphragm 23 marginal portions and front case 25, rear housing 21 marginal portion interference contacts connect, front case 25, rear housing 21 connects in its marginal portion riveted joint, the space that forms between front case 25 and the diaphragm 23 is an epitrochoidal chamber 26 (also can be described as vacuum chamber) before the servo-unit, the space that forms between rear housing 21 and the diaphragm 23 is epitrochoidal chamber 22 behind the servo-unit (also can be described as atmosphere chamber), big pull back spring 27 1 ends withstand on the shank portion of valve body 19, and the other end withstands on the front case 25.

With reference to figure 4,5,6,7, a kind of mechanical vacuum booster with emergency braking function, its control valve assembly comprises valve body 19, input bar 1, filter screen spring perch 20, cone-shaped spring 3, spring perch 4, compression spring 5, vacuum leather cup 6, trigger mechanism 17, trigger mechanism spring 8, plunger 7, locking plate 9, locking plate spring 16, valve piece 11, ratio dish 12, reaction plate 13, take-off lever 14, circlip 15 and rubber seal 10 and 18, described input bar 1 passes filter screen spring perch 20 successively, cone-shaped spring 3, spring perch 4, compression spring 5, vacuum leather cup 6, its bulb partly stretches in plunger 7 counterbores, input bar 1 and plunger 7 link together by riveted joint, but the input bar can rotate relative to plunger, the step 20a that step 1a on the described input bar 1 is pressed in filter screen spring perch inwall goes up the connection of contact left-hand thread, described spring perch 4 is pressed on the end face of the first boss 19a in the valve body 19, cone-shaped spring 3 is between filter screen spring perch 20 and spring perch 4, described vacuum leather cup 6 one ends have internal buckle ring 6b to be positioned at valve body first boss 19a inboard and are buckled in the circular groove of spring perch 4 lower ends, the other end end face 6a of vacuum leather cup is connected with second boss 19b contact in the valve body in the process of work, forms vacuum valve between the second boss 19b in the end face 6a of described vacuum leather cup and the valve body; Described trigger mechanism 17 is made up of two parts: outer wall have many free air diffusers, inwall have step cylindrical portions may and with the spring leaf of a plurality of symmetric arrangement of cylindrical portions may bonded assembly, the spring leaf centre portion has inwardly protruded boss 17d, described boss both sides all have domatic, and the spring leaf end has hook 17e; Described trigger mechanism 17, its cylindrical portions may are set in plunger 7 outsides, and first step face 7b is buckled on the interior step face 17b of cylindrical portions may on the plunger outer wall, and its exterior boss 17a and vacuum leather cup end face 6a fitted when cylindrical portions may moved up; And between plunger outer wall and trigger mechanism cylindrical portions may inwall, set up rubber seal 18, seal; Described trigger mechanism spring 8 one ends withstand on interior the 3rd boss 19c of valve body, and the other end withstands on the outer step surface 17c of trigger mechanism cylindrical portions may, makes trigger mechanism 17 that the trend of moving behind the relative valve body 19 be arranged; Described plunger 7 centre portion outer walls have annular groove, locking plate 9 is a U-shaped, locking plate 9 passes the radially slotted eye in the valve body 19, and be enclosed within on the annular groove of plunger outer wall, locking plate 9 can the radially slotted eye in valve body 19 in upper edge plunger 7 upper and lower moving, described locking plate spring 16 is sleeved on plunger 7 outsides, and an end contacts with the 4th boss 19d end face in the valve body, and the other end withstands on the locking plate 9 centre portion end face 9a; When the servo-unit initial condition, described locking plate centre portion contacts with the boss 17d of trigger mechanism spring leaf centre portion, and spring leaf is outwards opened; On described valve piece 11 outer walls step and groove are arranged, the valve piece contacts with the interior round boss 19g end face of valve end by the step surface 11a on the outer wall, and valve piece step outer wall and described in set up rubber seal 10 between the round boss 19g inner hole wall, with the forward and backward epitrochoidal chamber 26 of servo-unit and 22 isolated; Described take-off lever 14 1 ends have circular groove, are placed with reaction plate 13 in the circular groove, and described reaction plate 13 tops are placed with valve piece 11; An annular edge is arranged along 11b on the groove on the described valve piece outer wall, the terminal hook of described trigger mechanism spring leaf 17e can hang over described annular edge along on the 11b when servo-unit is implemented emergency braking; Have through hole in the described valve piece 11, the throughhole portions that external diameter is big is placed ratio dish 12.

1. incipient state (vacuum is arranged or do not have vacuum) balance position

Fig. 8 with reference to the accompanying drawings 7,, under the effect of valve body return big spring 27, locking plate 9 two end portions withstand on the rear housing 21, and promptly the end face 9b of locking plate 9 contacts with interior step surface 21a on the rear housing 21, simultaneously, in locking plate 9 centre portion right side 9a and the valve body 19 radially slotted eye right side 19f contact.Because the effect of cone-shaped spring 3, plunger middle part annular groove right side 7e contacts with locking plate middle part right side 9a.In incipient state, because the inner convex platform 17d on the trigger mechanism spring leaf is by locking plate 9 middle part jack-up, the trigger mechanism spring leaf outwards opens, the terminal hook of trigger mechanism spring leaf 17e is not contacted along 11b by the annular edge on the valve piece 11 outer wall grooves, be that the terminal hook of trigger mechanism spring leaf 17e is not hooked along 11b by the annular edge on the valve piece outer wall groove, thereby, trigger mechanism 17 is under the effect of trigger mechanism spring 8, its exterior boss 17a top is to vacuum leather cup 6, make the vacuum valve that forms between the second boss 19b in vacuum leather cup end face 6a and the valve body be in open mode, because step surface 17b contacts with plunger outer wall first step face 7b in trigger mechanism 17 cylindrical portions may, be that trigger mechanism 17 is spacing by plunger 7, trigger mechanism 17 can only back down vacuum leather cup 6 certain distances, thereby the aperture of vacuum valve is defined, and this aperture can be adjusted by designing.Form the atmosphere valve between trigger mechanism cylindrical portions may outer lug boss 17a and the vacuum leather cup end face 6a, this moment, the atmosphere valve was in closed condition.

2. normal brake application working process

With reference to the accompanying drawings 9, the beginning glancing impact, brake pedal force overcomes cone-shaped spring 3 drags, promoting input bar 1 moves forward, input bar 1 promotes plunger 7 again and moves forward, while plunger 7 promotes trigger mechanism 17 again and moves forward, thereby trigger mechanism cylindrical portions may outer lug boss 17a relative vacuum leather cup end face 6a is moved forward, vacuum leather cup end face 6a moves forward under the effect of compression spring 5, contact with the second boss 19b in the valve body up to vacuum leather cup end face 6a, vacuum valve, atmosphere valve all are in closed condition at this moment, and preceding epitrochoidal chamber 26 and back epitrochoidal chamber 22 are isolated.Along with input bar 1 continues reach, trigger mechanism cylindrical portions may outer lug boss 17a separates with vacuum leather cup end face 6a, the atmosphere valve open, and atmosphere enters valve body 19 inside along the dotted line direction among Fig. 9, enter into the back epitrochoidal chamber by the radially slotted eye on the valve body again then, servo-unit begins power-assisted.Under the epitrochoidal chamber pressure differential effect of front and back, the drag that valve body 19 overcomes big pull back spring 27 moves forward, locking plate 9 and then leaves rear housing 21, locking plate 9 moved up to locking plate 9 behind relative valve body 19 under the effect of locking plate spring 16 and contacted to slotted eye left side 19e with valve block internal diameter this moment, thereby make the inner convex platform 17d on the trigger mechanism spring leaf obtain to discharge, annular edge on the inclined-plane of the terminal hook of trigger mechanism spring leaf 17e and the valve piece outer wall groove contacts along the inclined-plane of 11b, and the inclined-plane along annular edge along 11b is to front slide, but trigger mechanism spring leaf hook 17e is not hooked along 11b by annular edge, in the process of normal brake application, as long as input force is no more than setting value, trigger mechanism spring leaf hook 17e just can not cross annular edge on the valve piece outer wall along 11b, so trigger mechanism 17 can not hooked by valve piece 11 in the process of front slide.

When keeping a certain power, brake pedal is worth when constant, it is motionless that plunger 7 and trigger mechanism 17 rest on a certain position, because valve body 19 mobile lags behind moving of plunger 7, so this moment, valve body 19 still can move forward under the pressure differential effect, vacuum leather cup end face 6a also moves forward under the effect of compression spring 5, the second boss 19b, trigger mechanism outer lug boss 17a contact in vacuum leather cup end face 6a and valve body, atmosphere valve, vacuum valve all are in closed condition at this moment, and servo-unit is in the brake compensation state.

Loosen the brake, input force diminishes, and input bar 1 moves under the effect of cone-shaped spring 3 backward, and it is mobile backward to drive plunger 7.Because the effect of trigger mechanism spring 8, trigger mechanism can move together backward in company with plunger, and then the cylindrical portions may outer lug boss 17a of trigger mechanism can back down vacuum leather cup 6 second boss 19b in the valve body, this moment, vacuum valve was opened, the atmosphere valve closing, the forward and backward epitrochoidal chamber of servo-unit begins pressure release.Under the effect of valve body return big spring 27, valve body 19 beginnings are moved backward, when locking plate 9 with after rear housing 21 contacts, locking plate is limited slack, and this moment, valve body 19 continues to move backward under the effect of return big spring 27, and the inner convex platform 17d on the trigger mechanism spring leaf is by locking plate 9 middle part jack-up, the trigger mechanism spring leaf outwards opens, and the hook 17e of trigger mechanism spring leaf end is separated along 11b with the annular edge on the valve piece outer wall groove.Valve body 19 continues to move backward, and right side 9a contacts (as shown in Figure 7) with valve block internal diameter to slotted eye right side 19f until the locking plate middle part, and this moment, servo-unit was got back to incipient state position shown in Figure 7 again.

Under the perfect condition, the input-output characteristic curve of servo-unit such as the abcd section among Figure 13 in the normal brake application process.

3. emergency braking working process

1) emergency braking excitation process

With reference to the accompanying drawings 10, during emergency braking, brake pedal is stepped on rapidly, drive input bar 1, plunger 7 move forward fast with trigger mechanism 17 relative valve bodies 19, under the effect of compression spring 5, the end face 6a of vacuum leather cup 6 withstands on the interior second boss 19b of valve body, close vacuum valve, preceding epitrochoidal chamber 26 and back epitrochoidal chamber 22 is isolated, form bigger gap between trigger mechanism cylindrical portions may outer lug boss 17a and the vacuum leather cup end face 6a, be that the atmosphere valve opening degree is bigger, atmosphere dotted line direction in the figure enters in the epitrochoidal chamber 22 of back, and is the same with the normal brake application process.Back epitrochoidal chamber 22 beginnings enter atmosphere fast, valve body 19 begins reach, locking plate 9 contacts to the slotted eye left side with valve block internal diameter under the effect of locking plate spring 16, thereby make the inner convex platform 17d on the trigger mechanism spring leaf obtain to discharge, annular edge on the inclined-plane of the terminal hook of trigger mechanism spring leaf 17e and the valve piece outer wall groove contacts along the inclined-plane of 11b, and the inclined-plane along annular edge along 11b is to front slide, and crosses valve piece annular edge along 11b.Under the situation that the input bar stands fast, the annular edge on trigger mechanism spring leaf terminal hook 17e inner end surface and the valve piece outer wall groove is along there being a gap e between the outer face of 11b.The aperture of atmosphere valve when limiting emergency braking, design has second step face 7c on plunger 7 outer walls, crossing urgent glancing impact, second step face 7c on the plunger outer wall can contact with the 3rd boss 19c in the valve body, thereby define plunger 7 and the distance that trigger mechanism 17 moves relative to valve body 19, also just define the maximum opening of atmosphere valve.When emergency braking, the second boss 19b is made as a to the distance between the trigger mechanism cylindrical portions may outer lug boss 17a in the valve body, and the distance between trigger mechanism cylindrical portions may outer lug boss 17a and the plunger outer lug boss 7a is made as b, and the size of a is the opening degree of atmosphere valve.

2) emergency braking keeps process

With reference to the accompanying drawings 11, in the process of emergency braking, if brake pedal pedal force deficiency, brake pedal can upwards lift, input bar 1 can drive plunger 7 and retreat, this moment is under the effect of trigger mechanism spring 8, trigger mechanism 17 also can be drawn back, disappear until above-mentioned gap e, be that trigger mechanism 17 is hooked by valve piece 11, if at this moment brake pedal continues upwards to lift, input bar 1 can drive plunger 7 to be continued to retreat, but trigger mechanism 17 is then opened by the atmosphere valve that forms between trigger mechanism cylindrical portions may outer lug boss 17a and the vacuum leather cup end face 6a owing to hooked and will can not retreat with plunger 7 by valve piece 11 always, move backward to its outer lug boss 7a up to plunger 7 and contact, then close by the second largest air valve that forms between plunger outer lug boss 7a and the vacuum leather cup end face 6a with vacuum leather cup end face 6a.If the distance in plunger outer lug boss 7a and the valve body between the second boss 19b is x, in the process that plunger is drawn back, as long as satisfy following condition apart from x:

0＜x＜a+b-e

Then the atmosphere valve is often opened, and atmosphere communicates with back epitrochoidal chamber 22, and servo-unit produces maximal servo power and is held, thereby makes the power output of servo-unit can produce the requirement of satisfying braking force required under the emergency braking situation.

A. little treadle effort realizes that braking force keeps

When implementing emergency braking, the feedback force part of reaction plate 13 is passed to valve body 19, and another part passing ratio dish 12 feeds back to plunger 7, and then pass to and import bar 1, also promptly in the process of emergency braking, the power that the people imposes on pedal should overcome the drag of cone-shaped spring 3, overcomes the part feedback force again.Feed back to plunger 7 power depend on the gap h of step surface 11c under emergency braking excited state situation in ratio dish step surface 12b and the valve piece.If the x value is greater than h, when then plunger 7 is return h, step surface 11c contacts in ratio dish step surface 12b and the valve piece, and this moment, the ratio dish 12 can not retreat again, and the distance that plunger 7 still can rollback x-h, along with further retreating of plunger 7, plunger head end face 7f and ratio dish end face 12a break away from, and to feed back to the power of plunger 7 be zero to reaction plate 13 like this, promptly in the maintenance process, treadle effort only need overcome the drag of cone-shaped spring 3, and all risk insurance of braking force is held process in the time of just keeping emergency braking.

B. the part treadle effort realizes that braking force keeps

If above-mentioned x value is less than the h value, when then plunger 7 was return x, plunger outer lug boss 7a contacted with vacuum leather cup end face 6a, and ratio dish 12 can also be return the distance of h-x, ratio dish step surface 12b just contacts with the interior step surface 11c of valve piece, and promptly reaction plate 13 also has the part feedback force to pass to plunger 7.Along with further returning of plunger 7, second largest air valve is closed, and vacuum valve is opened, and epitrochoidal chamber begins pressure release before and after the servo-unit.So, required servo force when being maintained emergency braking, the treadle effort that chaufeur applies must overcome the drag of cone-shaped spring 3 and the feedback force of part reaction plate 13, guarantees the distance that plunger 7 can not return x, the requirement of required braking force in the time of could satisfying emergency braking like this.Here it is, and the part treadle effort is realized the emergency braking pressure maintaining period, and the size of this part treadle effort can be adjusted at any time according to the requirement of different automobile types.

3) emergency braking dispose procedure:

With reference to the accompanying drawings 12, behind emergency braking, lift brake pedal in a flash, under the effect of cone-shaped spring 3, the terminal hook of trigger mechanism spring leaf 17e is hooked along 11b by the annular edge on the valve piece outer wall groove, along with further lifting of pedal, input bar 1 drives plunger 7 and moves backward together, but trigger mechanism 17 can be with moving behind the plunger 7.Along with moving behind the plunger 7, plunger outer lug boss 7a backs down vacuum leather cup end face 6a second boss 19b in the valve body, thereby opens vacuum valve, meanwhile, close by the second largest air valve that plunger outer lug boss 7a and vacuum leather cup end face 6a form, closed the plasmas channel of back epitrochoidal chamber 22.Along with the unlatching of vacuum valve, epitrochoidal chamber 26 and back epitrochoidal chamber 22 are by the dotted line channel connection among Figure 12 before the servo-unit, and servo-unit begins pressure release, under the effect of valve body return big spring 27, move after valve body 19 beginnings.When locking plate 9 with after rear housing 21 contacts, locking plate 9 stops to move, and valve body 19 moves after continuing, after sending out mechanism 17, move valve body 19 back shipper pole movable contacts, thereby the inner convex platform 17d on the trigger mechanism spring leaf is outwards backed down by locking plate 9, cause the terminal hook of trigger mechanism spring leaf 17e to break away from the annular edge of valve piece 11 along 11b, this moment is in the effect of trigger mechanism spring 8, trigger mechanism 17 can move backward, trigger mechanism cylindrical portions may outer lug boss 17a contacts and forms first air valve with vacuum leather cup end face 6a again, has replaced the second largest air valve that forms by between plunger outer lug boss 7a and the vacuum leather cup end face 6a.After pressure release reached state of equilibrium, whole servo-unit was got back to incipient state again, and as shown in Figure 7, first air valve is closed, vacuum break valve.

Under perfect condition: when above-mentioned x value during greater than the h value, under the emergency braking condition, the input-output characteristic curve of servo-unit is as figure abecd section; When above-mentioned x value during less than the h value, under the emergency braking condition, the input-output characteristic curve of servo-unit is as figure A Bo abfgcd section.

Claims (1)

1. mechanical vacuum booster with emergency braking function, its control valve assembly comprises valve body, the input bar, the filter screen spring perch, cone-shaped spring, spring perch, compression spring, the vacuum leather cup, trigger mechanism, the trigger mechanism spring, plunger, locking plate, the locking plate spring, the valve piece, the ratio dish, reaction plate, take-off lever, circlip and rubber seal, described input bar passes the filter screen spring perch successively, cone-shaped spring, spring perch, compression spring, the vacuum leather cup, its bulb partly stretches in the plunger counterbore, input bar and plunger link together by riveted joint, but the input bar can rotate relative to plunger, step on the described input bar is pressed in that the contact left-hand thread connects on the step of filter screen spring perch inwall, described spring perch is pressed on the first boss upper surface in the valve body, cone-shaped spring is between filter screen spring perch and spring perch, described vacuum leather cup one end has internal buckle ring to be positioned at valve body first boss inboard and is buckled in the circular groove of spring perch lower end, the other end end face of vacuum leather cup is connected with second boss contact in the valve body, forms vacuum valve between second boss in the end face of described vacuum leather cup and the valve body; It is characterized in that: described trigger mechanism is made up of two parts: outer wall have a plurality of free air diffusers, inwall have step cylindrical portions may and with the spring leaf of a plurality of symmetric arrangement of cylindrical portions may bonded assembly, the spring leaf centre portion has inwardly protruded boss, described boss both sides all have domatic, and the spring leaf end has hook; Described trigger mechanism, its cylindrical portions may is set in the plunger outside, has step to be buckled on the interior step of cylindrical portions may on the plunger outer wall, and its upper surface and vacuum leather cup were fitted when cylindrical portions may moved up; And between plunger outer wall and trigger mechanism cylindrical portions may inwall, set up rubber seal, seal; Described trigger mechanism spring one end withstands on interior the 3rd boss of valve body, and the other end withstands on the trigger mechanism cylindrical portions may end face, makes trigger mechanism that the trend of moving behind the relative valve body be arranged; Described plunger centre portion outer wall has annular groove, locking plate is a U-shaped, locking plate passes the radially slotted eye in the valve body, and be enclosed within on the annular groove of plunger outer wall, locking plate can move along plunger is upper and lower in the radially slotted eye in valve body, described locking plate spring housing is contained in the plunger outside, and an end contacts with the 4th raised head face in the valve body, and the other end withstands on the locking plate centre portion end face; When the servo-unit initial condition, described locking plate centre portion contacts with the boss of trigger mechanism spring leaf centre portion, and spring leaf is outwards opened; On the described valve piece outer wall step and groove are arranged, the valve piece contacts with the interior round boss end face of valve end by the step surface on the outer wall, and valve piece step outer wall and described in set up rubber seal between the round boss inner hole wall, the forward and backward epitrochoidal chamber of servo-unit is isolated; Described take-off lever one end has circular groove, is placed with reaction plate in the circular groove, and described reaction plate top is placed with the valve piece; On the groove on the described valve piece outer wall annular edge edge is arranged, the terminal hook of described trigger mechanism spring leaf can hang over when servo-unit is implemented emergency braking on the described annular edge edge; Have through hole in the described valve piece, the throughhole portions that external diameter is big is placed the ratio dish.

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