JPH046574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an assembly of a master cylinder and a hydraulic booster, and more particularly, to a master piston that is connected to a cylinder hole of the master cylinder in order to generate hydraulic pressure. and a booster piston that is slid into the cylinder hole of the booster cylinder and is actuated with boost according to the input, an output rod that contacts the back surface of the master piston, and a reaction mechanism that feeds back the operational reaction force of the master cylinder to the input side. It relates to an assembly formed by connecting via.

Traditionally, in such assemblies, the master and booster cylinders were provided with dedicated cylinder holes that individually guided the master and booster pistons of different diameters through their entire sliding strokes, so that the assembly The overall length is very long, so when installing it in the narrow engine room of a car, for example, to operate the hydraulic brake of a car,
Sometimes they interfered with the engine or its accessories, making its installation difficult.

SUMMARY OF THE INVENTION Therefore, the present invention provides an assembly having a short overall length by shortening the cylinder hole of the booster cylinder so that a part of the cylinder hole of the master cylinder can accommodate the front end of the advancing booster piston. With the goal.

In order to achieve this object, the present invention comprises a cylinder hole of a master cylinder consisting of a small diameter hole at the front and a large diameter hole at the rear whose diameter is larger than the front end of the booster piston, and the master piston is configured by The booster piston is comprised of a small-diameter piston part that slides into the small-diameter hole and a large-diameter piston part that slides into the large-diameter hole, and when the booster piston moves forward, it enters the large-diameter hole where the large-diameter piston part moves forward. It is characterized in that it is arranged close to the large diameter piston part so as to

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. First, in FIG.
This is a tandem type master cylinder for systematic hydraulic brakes, and an oil tank 2 is formed on the upper side of the cylinder body 1. The inside of the oil tank 2 is divided into a front oil sump 2 ₁ and a rear oil sump ₂ 2 by a partition wall 2 a in its lower half. It is divided into

The cylinder hole 3 of the cylinder body 1 is formed in a stepped manner by a small diameter hole 3a passing directly under the oil tank 2 and a large diameter hole 3b continuous to the rear end of the small diameter hole 3a. Small diameter hole 3
A shows the entire front master piston 4 that defines a front hydraulic chamber (not shown) that is supplied with oil from the front oil sump 2 ₁ between the front end wall of the cylinder hole 3 and the rear oil sump 2 ₂ . A rear master piston 5 defines a rear hydraulic chamber 6, which is supplied with oil, between the front master piston 4 and the rear hydraulic chamber 6.
The front end of the rear master piston 5, that is, the small diameter piston portion 5a, is slidably engaged with the large diameter hole 3b, and the rear end of the rear master piston 5, that is, the large diameter piston portion 5b is slidably engaged with the large diameter hole 3b. Therefore, the rear master piston 5 is composed of a small diameter piston part 5a and a large diameter piston part 5b having a larger diameter than the small diameter piston part 5a.

Both piston portions 5a and 5b provide a large diameter hole 3b.
A replenishment oil chamber 7 is defined in the area, and this oil chamber 7 is connected to an oil passage 8.
It communicates with the rear oil sump ₂₂ via.

An elastic piston cup 9 is attached to the front surface of the small-diameter piston portion 5a, and a relief port opens just before the piston cup 9 at the retraction limit of the rear master piston 5 and communicates between the rear hydraulic chamber 6 and the oil passage 8. 10 is bored in the cylinder body 1, and a through hole 11 is bored in the small diameter piston portion 5a to communicate the supply oil chamber 7 with the back of the piston cup 9.

The front hydraulic chamber (not shown) and the rear hydraulic chamber 6
A return spring 12 that urges the front and rear master pistons 4 and 5 in the backward direction is housed in the .

When the rear master piston 5 is pushed forward and the piston cup 9 crosses the opening of the relief port 10, hydraulic pressure is generated in the rear hydraulic chamber 6, and this hydraulic pressure is the brake hydraulic pressure communicating with the rear hydraulic chamber 6. A circuit (not shown) is supplied.

When the rear master piston 5 retreats from the forward position and the rear hydraulic chamber 6 is depressurized, the outer periphery of the piston cup 9 bends forward due to the pressure difference between the front and rear, creating a gap between it and the inner surface of the cylinder hole 3. result,
The oil in the rear oil sump ₂₂ flows into the rear hydraulic chamber 6 through the oil passage 8, the replenishment oil chamber 7, and the through hole 11 to replenish the hydraulic oil. The oil is returned to the rear oil sump ₂₂ through the relief port 10.

The front master piston 4 moves forward as the pressure in the rear hydraulic chamber 6 increases, generates hydraulic pressure in the front hydraulic chamber, and supplies this to the corresponding brake hydraulic circuit. Furthermore, when the piston 4 retreats, the oil in the front oil reservoir ₂₁ is replenished into the front hydraulic chamber, and the mechanism for generating this oil pressure and the oil replenishment mechanism are almost the same as those on the rear hydraulic chamber 6 side. Therefore, detailed explanation thereof will be omitted.

As clearly shown in FIG. 2, a booster cylinder 16 of a hydraulic booster B is connected to the rear end of the cylinder body 1 of the master cylinder M with a guide ring 15 in between, and the cylinder body 1 and the booster cylinder 16 are connected by bolts 17. tied together.

Here, the diameter of the small diameter hole 3a of the cylinder hole 3 of the master cylinder M is D ₁ , the diameter of the large diameter hole 3b is D ₂ ,
The inner diameter of the guide ring 15 is D ₃ and the booster cylinder 16 is
Assuming that the diameter of the cylinder hole 18 is _D4 , these dimensions are set in the following relationship.

D ₁ <D ₃ <D ₄ <D ₂ The small-diameter piston portion 19a and the large-diameter piston portion 19b of the booster piston 19 are slid into the guide ring 15 and the cylinder hole 18 of the booster cylinder 16, respectively, and the rear of the large-diameter piston portion 19b The rod portion 19c protruding from the end face is the booster cylinder 16.
It penetrates the rear end wall in an oil-tight manner and projects to the outside.
In order to define the retraction limit of the booster piston 19, a stepped portion 18a capable of supporting the rear end surface of the large diameter piston portion 19b is formed at the rear end of the cylinder hole 18.

Therefore, in the cylinder hole 18, the guide ring 15
The large diameter piston portion 19b and the rear end wall of the booster cylinder 16 define an output hydraulic chamber 21 therebetween. The output hydraulic chamber 21 is naturally formed to have a larger pressure receiving area than the input hydraulic chamber 20. Also, the large diameter piston portion 5b of the rear master piston 5 of the master cylinder M and the booster piston 1
The small diameter piston portion 19a of No. 9 has an outlet chamber 22 therebetween.
Define.

The input hydraulic chamber 20 is connected to the oil tank 2 by a supply oil passage 23, and the oil passage 23 is connected to a hydraulic pump 24 that pumps the oil stored in the oil tank 2 to the input hydraulic chamber 20.
is interposed, and a pressure accumulator 25 is connected downstream of the pump 24.

An inlet valve 26 and an outlet valve 27 are arranged in parallel on the booster piston 19 .

The inlet valve 26 has a booster piston 19 in the middle of an oil passage 28 that communicates between the input and output hydraulic chambers 20 and 21.
a cylindrical valve chamber 29 formed along the axial direction of the valve chamber 29; a spherical valve body 30 that opens and closes the oil passage 28 in cooperation with a valve seat formed on the rear end wall of the valve chamber 29; A valve spring 31 biases the valve body 30 in the closing direction within the valve spring 31.
and an operating rod 32 that can open the valve body 30 against the force of the valve spring 31. The operating rod 32, which is configured as a normally closed type, is fitted into the booster piston 19 so as to be slidable in its axial direction. The rear end portion protrudes into the output hydraulic chamber 21 .

The outlet valve 27 is composed of a valve cylinder 33 fitted to the booster piston 19 on the axis of the piston 19, and a valve piston 35 slidably engaged with the inner hole of the valve cylinder 33, that is, the valve hole 34. The rear end of the piston 35 is connected to a brake pedal 37 via a push rod 36. The valve cylinder 33 is the output hydraulic chamber 21
It has an outlet port 38 communicating with the valve piston 35.
has an annular groove 39 that blocks and communicates with the outlet port 38 according to its advance/retreat, and an oil passage 40 continuous with the annular groove 39. This oil passage 40 is communicated with the outlet chamber 22 via an oil passage 41 formed in the booster piston 19, and the outlet chamber 22 is connected to a radial groove 42 (fourth
(see figure), is communicated with the oil tank 2 via an annular oil passage 43 formed at the rear end of the cylinder body 1 and a return oil passage 44 connected to the oil passage 43.

In the output hydraulic chamber 21, a pin 45 is fitted into the valve piston 35 so as to be perpendicular to its axis. Both ends of the pin 45 pass through long holes 46 and 47 in the axial direction formed in the valve cylinder 33 and the rod portion 19c of the booster piston 19, respectively, and are connected to the rod portion 19c.
The projecting ends 45a, 45 protrude from the outer circumferential surface of the
a is formed into a truncated conical shape. Both protruding ends 4
5a, 45a, as shown in FIG.
8 connection holes 49, 49 are fitted, and this pin 45
A coil spring 50 is wound around the outer periphery of the interlocking ring 48 in order to maintain the connected state of the interlocking ring 48. The interlocking ring 48 is disposed opposite to the rear end of the inlet valve 26 so as to push the operating rod 32 of the inlet valve 26 forward in response to the advance of the valve piston 35.

In order to define the retracting limit of the valve piston 35, a circlip 51 capable of supporting the rear end surface is engaged with the inner circumferential surface of the rod portion 19c, and a return spring 52 that biases the valve piston 35 in the retracting direction is attached to the rod portion. 19c and the valve piston 35. This return spring 52 is connected to the booster piston 19 of the valve cylinder 33.
It also has the function of maintaining a fixed position.

Here, when the booster piston 19 and the valve piston 35 are at their respective backward limits, the forward stroke of the valve piston 35 required to close the outlet valve 27 is _L1 , and the forward stroke of the valve piston 35 required to open the inlet valve 26 is L1. If the forward stroke of is L ₂ , then
It is set as L ₁ /L ₂ .

The booster piston 19 has a large-diameter hole 53 that opens on its front surface, and a large-diameter hole 53 that connects the valve hole 3 to the large-diameter hole 53.
4, a small diameter hole 54 is bored, and a rubber elastic piston 55 and a pressure receiving piston 56 of the same diameter are slid into the large diameter hole 53 in order from the back thereof, and a valve piston 35 is inserted into the small diameter hole 54. A reaction piston 57 whose both ends can come into contact with the opposing surface of the elastic piston 55 is slidably connected thereto.

An output rod 58 is integrally bored in the front surface of the pressure receiving piston 56, and this output rod 58 deeply penetrates into a recess 59 on the rear surface of the rear master piston 5 and comes into contact with the piston 5. Piston 5 and booster piston 19 are arranged as close as possible.

The depth of the recess 59 is determined by the depth of the rear master piston 5.
The radius is selected to be equal to or larger than the radius of the large diameter piston portion 5b. In this way, when the rear master piston 5 is pushed by the output rod 58, an alignment effect can be applied to the piston 5.

In the above, the pressure receiving piston 56, the elastic piston 55 and the reaction piston 57 are connected to the master cylinder M
A reaction mechanism R is configured to transmit the actuation reaction force to the valve piston 35.

Next, the operation of this embodiment will be explained.

When the brake pedal 37 is not actuated, the valve piston 35 is held at the retracting limit by the force of the return spring 52 together with the interlocking ring 48, as shown in the figure, and the annular groove 3
9 occupies a position communicating with the outlet port 38,
The outlet valve 27 is in an open state. On the other hand, in the inlet valve 26, the operating rod 32 is released from the interlocking ring 48, and the valve body 30 is seated on the valve seat of the valve chamber 29 with the force of the valve spring 31, so that the valve is in the closed state. ing. Therefore, the input and output hydraulic chambers 20, 21
The output hydraulic chamber 21 is connected to the outlet port 38, the annular groove 39, the oil passage 40, the outlet chamber 22, the radial groove 42, and the annular oil passage 43.
The front and rear master pistons 4 and 5 and the booster piston 19 are moved to their retracting limits by the force of the return spring 12 of each master piston. is maintained.

Furthermore, in this case, hydraulic pressure from the hydraulic pump 24 or the pressure accumulator 25 is introduced into the input hydraulic chamber 20, and this hydraulic pressure acts on the front surface of the large diameter piston portion 19b of the booster piston 19. Booster piston 19 is held at the backward limit. Further, since the spherical valve body 30 has a high obstructing property, leakage of pressure oil from the input hydraulic chamber 20 to the output hydraulic chamber 21 can be reliably prevented.

Now, to brake the car, brake pedal 37 is pressed.
When the brake pedal 37 is depressed, the valve piston 35 and the interlocking ring 48 are
is pushed forward, and due to the relationship L ₁ <L ₂ , the annular groove 39 is first shut off from the outlet port 38, that is, the outlet valve 27 is closed. The interlocking ring 48 then comes into contact with the rear end of the operating rod 32 and pushes it forward, thereby separating the valve body 30 from the valve seat, ie, closing the inlet valve 26. As a result, the communication between the output hydraulic chamber 21 and the oil tank 2 is cut off, and the hydraulic pressure introduced into the input hydraulic chamber 20 from the hydraulic pump 24 or the pressure accumulator 25 passes through the oil passage 28 and the valve chamber 29 to the output hydraulic chamber 2.
1, the booster piston 19 moves forward in response to the hydraulic pressure on its rear end surface, and moves the rear master piston 5 forward via the reaction mechanism R and the output rod 58. That is, the master cylinder M is actuated with boost.

Then, the booster piston 19 advances its front end into the large diameter hole 3b of the master cylinder M so as to follow the rear master piston 5. In this way, the large-diameter hole 3b not only guides the large-diameter piston part 5b of the rear master piston 5, but also guides the booster piston 19, which moves forward following the forward movement trace of the large-diameter piston part 5b.
It also serves to receive the front end of the.

The booster piston 19 is the rear master piston 5
While pushing , the pressure receiving piston 56 receives the actuation reaction force of the master cylinder M from the rear master piston 5 and operates to compress the elastic piston 55 , and a part of the compression force acts on the reaction piston 57 . Feedback is then fed back to the valve piston 35 via the brake pedal 37 via the push rod 36, so that the driver can sense the magnitude of the braking force. The boost ratio at this time is S _{1 /S 2 where the cross-sectional area of the pressure receiving piston 56 is S 1 and the} cross-sectional area of the reaction piston 57 is S ₂ .

In the illustrated example, the oil tank 2 of the master cylinder M is used as the oil tank of the hydraulic booster B, but an oil tank exclusively for the hydraulic booster B may be provided.

As described above, according to the present invention, the cylinder hole of the master cylinder is composed of a small diameter hole in the front part and a large diameter hole in the rear part with a diameter larger than the front end of the booster piston, and the master piston is slidably fitted into the small diameter hole. The booster piston is configured to include a small-diameter piston portion that slides into the large-diameter hole, and a large-diameter piston portion that slides into the large-diameter hole. Since the master piston is placed close to the large-diameter piston part, the small-diameter piston part and the large-diameter piston part at the front and rear ends of the master piston are both supported in the cylinder hole of the master cylinder, ensuring a sufficient support length and sliding. It is possible to stabilize the movement. Moreover, even though a relatively long master piston is used in this way, during boost operation, the front end of the booster piston is received in the cylinder hole where the large-diameter piston moves forward, so that the front end of the booster piston is received in the cylinder hole where the large-diameter piston moves forward. The length of the cylinder hole of the booster cylinder is shorter than that of the conventional one, and as a result, an assembly with a shortened overall length can be obtained, and can be easily installed in a narrow engine room of an automobile.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional side view showing one embodiment of the assembly of the present invention, FIG. 2 is an enlarged view of its main parts, and FIG.
Figure 4 is an enlarged cross-sectional view of Figure 1.
FIG. M...Master cylinder, B...Hydraulic booster,
R...Reaction mechanism, 1...Cylinder body, 3...Cylinder hole, 3a, 3b...Small, large diameter hole, 5...Master piston, 5a, 5b...Small, large diameter piston part, 16... Booster cylinder, 15...Guide ring, 18...Cylinder hole, 19...Booster piston, 19a, 19b...Small and large diameter piston parts,
20, 21... Input, output hydraulic chamber, 24... Hydraulic pump, 25... Pressure accumulator, 26, 27... Input, outlet valve, 35... Valve piston, 37... Brake pedal, 48... Interlocking ring , 58...output rod.

Claims (1)

[Claims] 1 A booster cylinder 16 is connected to the rear of the master cylinder M, and the cylinder hole 3 of the master cylinder M is
The master piston 5 is slid together to generate hydraulic pressure.
and the booster piston 19 which is slid into the cylinder hole 18 of the booster cylinder 16 and is actuated with boost according to the input, the output rod 58 which contacts the back surface of the master piston 5, and the operational reaction force of the master cylinder M are input. In an assembly of a master cylinder and a hydraulic booster, which are connected via a reaction mechanism R that feeds back to the side, the cylinder hole 3 of the master cylinder M has a diameter larger than that of the small diameter hole 3a at the front and the front end of the booster piston 19. Large diameter hole 3b at the rear of
The master piston 5 includes a small-diameter piston portion 5a that is slidably fitted into the small-diameter hole 3a, and a large-diameter piston portion 5b that is slidably fitted into the large-diameter hole 3b.
The booster piston 19 is arranged close to the large-diameter piston part 5b so that when the booster piston 19 moves forward, it enters the large-diameter hole 3b in the forward movement trace of the large-diameter piston part 5b. ,
Master cylinder and hydraulic booster assembly.