JPH106972A - Reaction force mechanism of booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reaction force which is unnecessarily large from being transmitted to a driver when a vehicle is operated abruptly by preventing reac tion force applied on an output shaft from being transmitted to a valve plunger and providing a pseudo-reaction force providing means which gives necessary pseudo-reaction force to the driver. SOLUTION: An input shaft 19 and a valve plunger are advanced by stepping a braking pedal 21 in, and an output shaft advances to generate brake liquid pressure in a master cylinder. All brake reaction force due to the brake liquid pressure is received by a valve body through the output shaft, an elastic body, and a spacer and is not transmitted to the valve plunger. On the other hand, the brake pedal 21 pulls a first spring 36 of a pseudo-reaction force providing means 31 at first and then a second spring 42. Consequently, pseudo-reaction force which corresponds to its pulling force is generated in the brake pedal 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster used for a brake of an automobile, and more particularly to a reaction mechanism of a booster for applying a reaction force to an operating rod for operating the booster.

[0002]

2. Description of the Related Art Conventionally, a brake booster generally includes a valve body slidably provided in a shell, a power piston provided in the valve body, a constant pressure chamber and a variable pressure chamber formed before and after the power piston. An input shaft, which is interlocked with a valve mechanism provided in the valve body and a brake pedal as an operating rod, moves a valve plunger that constitutes the valve mechanism to switch the flow path of the valve mechanism, and moves forward by advancement of the valve body. And an output shaft for advancing the piston of the master cylinder to generate brake fluid pressure. The conventional general reaction mechanism has a rubber reaction disk disposed between the output shaft and the valve plunger. When the brake booster operates, the valve body and the valve plunger simultaneously contact the reaction disk. Then, a part of the brake reaction force applied to the output shaft is received by the valve body, and the remainder is transmitted to the valve plunger so that the driver can sense the brake reaction force applied to the valve plunger via the input shaft and the brake pedal. I have to. At this time, the ratio between the reaction force received by the valve body and the reaction force received by the valve plunger,
More specifically, the servo ratio of the brake booster can be changed by changing the ratio of the pressure receiving areas of the two.

[0003]

The servo ratio of the above-mentioned brake booster is generally set to a large value so that a large brake fluid pressure can be generated with a small brake pedal depression force. The expected large servo ratio could not be obtained due to the delay of the operation of the power device, and it was found that it was difficult for a weak driver such as an old man or a woman to perform sudden braking. That is, when the brake pedal is depressed, the flow path of the valve mechanism is switched via the input shaft, whereby the pressure fluid is introduced into the variable pressure chamber, and the power piston and the valve body are advanced. When the valve body advances, the output shaft advances through the reaction disk. When the output shaft advances, a brake fluid pressure is generated and the reaction force is applied to the output shaft. As described above, the brake reaction force applied to the output shaft is increased. Is distributed to the valve body and the valve plunger. However, at the time of sudden braking, before the power piston and the valve body are advanced by the pressure fluid introduced into the variable pressure chamber,
Since the valve plunger interlocked with the brake pedal via the input shaft is advanced, most of the brake reaction force applied to the output shaft is transmitted to the valve plunger,
As a result, the brake reaction force transmitted to the driver becomes abnormally large. As a result, when sudden braking is performed, the brake pedal must be depressed by overcoming the abnormally large brake reaction force. As compared with the case, a large braking force required for sudden braking could not be obtained unless the brake pedal was depressed with a much larger force.
The present invention has been made in view of such circumstances, and provides a reaction mechanism of a booster in which a large output can be obtained with a light pedaling force even during a sudden operation without impairing the operation feeling of a normal booster. It is.

[0004]

That is, the present invention provides a valve body slidably provided in a shell, a power piston provided in the valve body, a constant pressure chamber and a variable pressure chamber formed before and after the power piston. An input shaft that is interlocked with a valve mechanism provided in the valve body, is operated by an operating rod, and moves a valve plunger that constitutes the valve mechanism to switch the flow path of the valve mechanism; and an output shaft that is advanced by advancing the valve body. In this case, the reaction force applied to the output shaft during the operation of the booster is prevented from being transmitted to the valve plunger, and the pseudo-reaction having a small increase rate when the movement amount of the operating rod is small. A pseudo reaction force applying means for applying a force to the operation rod at a large increase rate when the movement amount of the operation rod is large is provided.

[0005]

According to the above construction, the reaction force applied to the output shaft during operation of the booster is prevented from being transmitted to the valve plunger. Even if the valve plunger interlocked with the operation rod via the input shaft is advanced before the valve body is advanced, the reaction force applied to the output shaft is transmitted to the driver via the valve plunger, the input shaft and the operation rod. It is not transmitted. On the other hand, the pseudo reaction force applying means transmits the pseudo reaction force corresponding to the moving amount of the operation rod to the driver via the operation rod, so that the reaction force becomes abnormally large during a sudden operation as in the related art. Thus, even during a sudden operation, a large output can be obtained with a light operating force, as in a normal operation. In particular, the pseudo reaction force applying means applies the pseudo reaction force having a small increase rate when the movement amount of the operation rod is small, and the pseudo reaction force having a large increase rate when the movement amount of the operation rod is large. , So that the same operation feeling as that of the conventional ordinary operation can be obtained irrespective of the time of sudden braking and the time of gentle braking. In other words, for example, when the operating lever is a brake pedal, the pseudo reaction force increases little when the brake pedal is depressed relatively large in the initial stage of braking, but after a certain amount of braking force is generated, the amount of depressing the brake pedal is reduced. Even if it is small, the pseudo reaction force relatively increases. The pseudo reaction force applying means having the above characteristics is effective in realizing such a conventional operation feeling.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a brake booster will be described below. Referring to FIG. 1, a substantially cylindrical valve body 3 is slidable in a sealed container formed by a front shell 1 and a rear shell 2. The sealed container is partitioned into a constant pressure chamber 6 on the front side and a variable pressure chamber 7 on the rear side by a power piston 4 provided on the outer peripheral portion of the valve body 3 and a diaphragm 5 attached to the rear side thereof. . The valve body 3 houses a valve mechanism 9 for switching a fluid circuit. The valve mechanism 9 includes an annular first valve seat 10 formed on the inner periphery of the valve body 3 and a valve body 3.
An annular second valve seat 12 formed at the right end of a valve plunger 11 slidably fitted therein;
0 and 12 are provided with a valve element 14 which is seated by a poppet return spring 13 from the right side in FIG. An outer peripheral side of the first valve seat 10 communicates with the constant pressure chamber 6 through an axial constant pressure passage 15 formed in the valve body 3, and the constant pressure chamber 6 is connected to a negative pressure introducing pipe 16 provided in the front shell 1. A negative pressure is always introduced into the constant-pressure chamber 6 by communicating with the intake manifold of the engine via the. An intermediate portion between the first valve seat 10 and the second valve seat 12 is communicated with the variable pressure chamber 7 through a radial variable pressure passage 17 formed in the valve body 3,
The inner peripheral side of the valve seat 12 communicates with the atmosphere via a pressure passage 18 formed in the valve body 3.

[0007] The right end of the valve plunger 11 is pivotally connected to the tip of an input shaft 19, and a larger repulsive force than the poppet return spring 13 is provided between the input shaft 19 and the valve body 3. A valve return spring 20 having a resilient force is mounted thereon, and the valve plunger 1 is usually mounted.
The valve body 14 is seated on the first second valve seat 12 and the valve body 14
From the first valve seat 10 of the valve body 3.
The distal end of the input shaft 19 is linked to a brake pedal 21 as described later in detail. Further, the valve plunger 11 is prevented from being pulled out of the valve body 3 by the key member 22. The key member 22
Although not shown, it is formed in a forked shape from the center portion to the tip portion, and the key member 22 is inserted into an insertion hole 23 formed in the diametrical direction of the valve body 3, and the base of the forked portion is inserted. The small diameter portion 11a of the valve plunger 11 is engaged. At this time, the insertion hole 23 and the variable pressure passage 17
Are integrally formed adjacent to each other in the axial direction of the valve body 3, but are orthogonal to the width of the insertion hole 23, that is, orthogonal to the axial direction of the valve body 3 and orthogonal to the insertion direction of the key member 22 into the insertion hole 23. The width in the direction is set wider than the width in the same direction of the variable pressure passage 17, whereby the key member 22
Can be displaced in the axial direction of the valve body 3 only in the insertion hole 23. Also, the key member 22 and the valve plunger 1
1 means that the key member 22 can be displaced in the axial direction of the valve body 3 within the range of the axial length of the small diameter portion 11a.
Of the key member 22 and the valve plunger 1
1 is held in the forward position with respect to the valve body 3, the input shaft 1 at the start of operation of the brake booster is started.
9 can be reduced. Further, a concave portion 24a is formed in the right base of the output shaft 24 disposed on the left side of the valve plunger 11, and a rubber elastic body 25 and a spacer 26 formed of a metal disk are sequentially fitted in the concave portion 24a. And the recess 2
An annular protruding portion 3a formed at the right end of the valve body 3 is slidably fitted in 4a. The left end portion of the output shaft 24 is protruded from the front shell 1 to the outside while maintaining airtightness by a sealing member 27, and the end portion is linked to a piston of a master cylinder (not shown) connected to the front shell 1 (not shown). I have. The valve body 3 and the power piston 4 are normally held at a non-operating position by a return spring 28.

Conventionally, the spacer 26 is omitted, and the left side surface of the valve plunger 11 is opposed to the elastic body 25 as a reaction disk with a small gap.
When the brake booster is operated, the valve body 3 and the valve plunger 11 receive the brake reaction force transmitted from the output shaft 24 via the elastic body 25, and
The brake reaction force received in 1 is transmitted to the driver via the input shaft 19 and a brake pedal (not shown). On the other hand, in this embodiment, the output shaft is provided by providing the spacer 26 and setting a relatively large space between the spacer 26 and the valve plunger 11 so as not to come into contact with each other even during sudden braking. All of the brake reaction force transmitted from the valve body 24 is received by the valve body 3 via the elastic body 25 and the spacer 26 so that the brake reaction force is not transmitted to the valve plunger 11 and therefore to the brake pedal. . In this embodiment, the elastic body 25 is used as a shock absorbing member. The elastic body 25 and the spacer 26
May be omitted, and the hole into which the left end of the valve plunger 11 is slidably fitted may be closed at the left end opening as long as the sliding of the valve plunger 11 is not hindered.

On the other hand, since the driver cannot obtain a feeling of operating the brake with the above configuration, the provision of the pseudo reaction force applying means 31 shown in FIG. A pseudo reaction force can be applied to the driver. That is, as shown in FIG. 2, one end of the brake pedal 21 is swingably connected to the vehicle body 33 by a connecting pin 32, and a first clevis 34 attached to one end of the input shaft 19 is provided.
The clevis pin 35 penetrates between the input shaft 19 and the brake pedal 21.
And are connected. As shown in FIGS. 2 and 3, a first spring 36 having a small elastic force is stretched between the clevis pin 35 and the vehicle body 33, and the brake pedal 21 is pulled by the tensile force of the first spring 36. Is normally brought into contact with a first stopper 37 (FIG. 2) provided on the vehicle body 33. The first spring 36 includes a clevis pin 35
Instead, it may be connected directly to the brake pedal 21 or to the first clevis 34 or the input shaft 19. The first clevis 34 has the input shaft 1 in the second clevis 41.
9 is provided so as to be able to advance and retreat in the axial direction, and both ends of the clevis pin 35 are
By engaging the first clevis 34 and the second clevis 41 with the long hole 41a formed in the axial direction of the
The relative movement can be made within the range of the length a. Further, between the second clevis 41 and the vehicle body 33, a second spring 42 having an elasticity greater than that of the first spring 36 is disposed in parallel with the first spring 36. The second clevis 41 is normally brought into contact with a second stopper 43 provided on the vehicle body 33 by the tensile force of the second spring 42. In this state, the clevis pin 35 is located on the rear side of the elongated hole 41a.

In the above configuration, the brake pedal 21
When the input shaft 19 and the valve plunger 11 are advanced by stepping on, the flow path of the valve mechanism 9 is switched and the atmosphere is introduced into the variable pressure chamber 7 as in the conventionally known brake booster. The power piston 4 and the valve body 3 are advanced by the pressure difference between the pressure chamber 6 and the variable pressure chamber 7, and the output shaft 24 is advanced accordingly, so that brake fluid pressure is generated in the master cylinder. The brake reaction force due to the brake fluid pressure is applied to the output shaft 24, the elastic body 25 and the spacer 26.
Are all received by the valve body 3 via the valve body 3 and are not transmitted to the valve plunger 11. On the other hand, when the brake pedal 21 is depressed, the brake pedal 21 first pulls the first spring 36 and then the second spring 42, so that the brake pedal 21 has a pseudo reaction corresponding to the pulling force. Power will be created. More specifically, when the brake pedal 21 is depressed, first, the elastic force of the first spring 36 acts on the brake pedal 21. And then the brake pedal 21
When the clevis pin 35 integral with the brake pedal 21 moves to the tip of the long hole 41a of the second clevis 41, the clevis pin 35 advances the second clevis 41 against the second spring 42. Because
The resilient force of the first spring 36 and the second spring 42 arranged in parallel act on the brake pedal 21 at the same time. FIG. 4 shows the relationship between the stroke of the brake pedal 21 and the pedaling force at this time. In the figure, a straight line A is a straight line obtained by the first spring 36, and its inclination is the spring constant k ₁ of the first spring 36.
And the intersection B between the straight line A and the horizontal axis can be set by the set load of the first spring 36. As can be understood from the straight line A, since the resilience of the first spring 36 is set to be small, the stroke greatly increases due to a small increase in the pedaling force of the brake pedal 21 at the beginning of braking. Next, point C in FIG.
The point is that the resilient force of the first spring 36 and the second spring 42 simultaneously act on the brake pedal 21, and the straight line D is a straight line obtained by the first spring 36 and the second spring 42. tilt can be set by the combined spring constant k of the spring constant k ₂ of the spring constant k ₁ and the second spring 42 of the first spring 36. The composite spring constant k is obtained by k = k ₁ + k ₂ , and the resilience of the second spring 42 is set to be larger than that of the first spring 36. Even if is greatly increased, the stroke will increase slightly. With the combination of the straight lines A and B described above, it is possible to obtain a better brake operation feeling than setting the relationship between the stroke and the pedaling force with one straight line, that is, one spring. The pseudo reaction force applied by the pseudo reaction force applying means 31 to the brake pedal 21 is substantially the same both at the time of sudden braking and at the time of normal braking, and is abnormally large at the time of sudden braking like the braking reaction force of the conventional device. Therefore, a large braking force can be obtained with a relatively light pedaling force even in the event of sudden braking, so that even a weak driver such as an elderly person or a woman can reliably perform the sudden braking operation.

FIG. 5 shows a second embodiment of the present invention. In the above embodiment, the first spring 36 and the second spring 42 are arranged in parallel, whereas in this embodiment,
Two springs are arranged in series. That is, the pseudo reaction force applying means 131 in the present embodiment includes two first springs 136 and second springs 1 arranged in series between the brake pedal 121 and the vehicle body 133 and connected to each other.
42. And both springs 136,
A stopper plate 151 is attached to a connecting portion of the 142, and the stopper plate 151 comes into contact with a stopper 152 provided on the vehicle body 133. In the non-operation state, the stopper plate 151 is
When the brake pedal 121 is depressed from this state, the two springs 13
6, 142 are pulled and the stopper plate 151 is pulled.
Comes into contact with the stopper 152, and in this state, only the first spring 136 on the brake pedal 121 side is pulled. The composite spring constant k when two springs connected in series are pulled is k = k ₁ ·, where the spring constants of each spring are k ₁ and k _2.
It is given by k ₂ / (k ₁ + k ₂ ). As is clear from this equation, the composite spring constant k is set so that the spring constant of each spring is smaller than k ₁ and k ₂ , and the straight line A in FIG. 4 can be obtained by the small composite spring constant k. Can be. On the other hand, after the stopper plate 151 abuts against the stopper 152, only the first spring 136 is pulled, so that by the spring constant k ₁ is the straight line D in FIG. 4 is obtained. In each of the above embodiments, one spring 36, 42,
Each of the 136 and 142 can be replaced by a plurality of springs connected in series or in parallel, so that the required composite spring constant can be obtained more flexibly.

FIG. 6 and FIG. 7 show a third embodiment of the present invention.
In 31, the valve return spring 20 shown in FIG. 1 is used as the first spring, and the torque spring 242 is used as the second spring. The torque spring 242 is wound around a connection pin 232 connecting the brake pedal 221 to the vehicle body 233, and one end 242 a of the torque spring 242 is provided on the brake pedal 221.
55, and the other end 242b is engaged in an arc-shaped groove 256a formed in a bracket 256 constituting a part of the vehicle body 233. The arc-shaped groove 256a is formed in an arc with the connection pin 232 as a center. The brake pedal 221 is normally held in a state where the stopper 255 is in contact with a stopper 257 provided on the vehicle body 233 side.
Is located at a position separated from the end of the arc-shaped groove 256a by a predetermined distance δ. When the brake pedal 221 is depressed from this state, the input shaft is advanced against the valve return spring 20, and when the other end 242b of the torque spring 242 contacts the end of the arc-shaped groove 256a, the brake is released. The elastic force of the torque spring 242 acts on the pedal 221. Therefore, the straight line A in FIG. 4 can be obtained by the valve return spring 20, and the straight line D in FIG. 4 can be obtained by the valve return spring 20 and the torque spring 242.

In the above embodiment, the brake pedals 21, 121, 221 are used as operating rods. However, the operating rod may be a manual brake lever used for a physically handicapped person. Further, the present invention can be applied to a clutch booster, in which case a clutch pedal can be used as an operating rod.

[0014]

As described above, according to the present invention, the reaction force applied to the output shaft is prevented from being transmitted to the valve plunger, and the required pseudo reaction force is applied to the driver by the pseudo reaction force applying means. Therefore, an unnecessary large reaction force is not transmitted to the driver at the time of sudden operation unlike the related art, and an effect that a large output required at the time of sudden operation can be obtained with a light pedaling force can be obtained. The pseudo reaction force applying means applies the pseudo reaction force having a small increase rate to the operation rod when the movement amount of the input shaft is small and the pseudo reaction force having a large increase rate when the movement amount of the operation rod is large. As a result, an effect is obtained that it is easy to realize the same operation feeling as in the conventional normal operation irrespective of the time of sudden braking and the time of gentle braking.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is an enlarged view showing a main part of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a characteristic diagram of the embodiment.

FIG. 5 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 6 is a front view showing a third embodiment of the present invention.

FIG. 7 is a side view of FIG. 6;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 front shell 2 rear shell 3 valve body 4 power piston 6 constant pressure chamber 7 variable pressure chamber 9 valve mechanism 11 valve plunger 19, 119, 219 input shaft 21, 21, 221 brake pedal 31, 131, 231 simulated reaction force applying means 33, 133, 233 Body 20, 36, 136, 42, 142, 242 Spring 34, 41 Clevis 35 Clevis pin 37, 43, 152 Stopper 151 Stopper plate

Claims (6)

[Claims] 1. A valve body slidably provided in a shell, a power piston provided on the valve body, a constant pressure chamber and a variable pressure chamber formed before and after the power piston.
An input shaft that is interlocked with a valve mechanism provided in the valve body, is operated by an operating rod, and moves a valve plunger that constitutes the valve mechanism to switch the flow path of the valve mechanism; and an output shaft that is advanced by advancing the valve body. A booster device comprising: a booster device that prevents a reaction force applied to the output shaft from being transmitted to the valve plunger when the booster device is operated, and that has a small increase rate when the amount of movement of the operating rod is small. A reaction force mechanism of a booster, comprising: a pseudo reaction force applying means for applying a large reaction rate of a pseudo reaction force to the operation rod when the movement amount of the operation rod is large. 2. The input shaft is interlocked with an operating rod via a first clevis and a clevis pin, and a first spring constituting pseudo reaction force applying means is provided between the input shaft and a vehicle body. The second that can move forward and backward within a certain range with respect to the rod
A clevis, and a second clevis between the second clevis and the vehicle body.
A spring is provided to normally contact the second clevis with a stopper, and when the operating rod is operated and advanced by a predetermined amount, the operating rod and the second clevis are integrally advanced. 3. A reaction force mechanism of the booster according to 2. 3. The input shaft is interlocked with an operating rod via a first clevis and a clevis pin, and a first reaction shaft is connected between the first and second clevis and a vehicle body.
2. The booster according to claim 1, wherein a spring and a second spring are provided, and a stopper plate provided at a connecting portion between the two springs can contact a stopper provided on the vehicle body. Power mechanism. 4. The booster according to claim 2, wherein at least one of the first spring and the second spring includes a plurality of springs connected in parallel. Reaction force mechanism. 5. The device according to claim 2, wherein at least one of the first spring and the second spring includes a plurality of springs connected in series. Reaction mechanism of booster. 6. The operating rod comprises a pedal that is swingably connected to the vehicle body with a connecting pin. A torque spring is wound around the connecting pin, and one end of the torque spring is applied to the pedal, and the other end is applied to the vehicle body. 2. The double according to claim 1, wherein the first and second contact portions are in contact with each other, and one of the contact portions has a fixed gap so that the contact is made after the pedal is depressed by a fixed amount. 3. Reaction mechanism of power device.