WO2019188144A1

WO2019188144A1 - Negative-pressure-type booster

Info

Publication number: WO2019188144A1
Application number: PCT/JP2019/009472
Authority: WO
Inventors: 健太石川
Original assignee: 株式会社アドヴィックス
Priority date: 2018-03-30
Filing date: 2019-03-08
Publication date: 2019-10-03
Also published as: JP2019177817A

Abstract

A negative-pressure-type booster 100 is provided with an annular seal member 170 that is interposed between an inner peripheral surface 112c of a tube part 112a provided to a booster shell 110 and an outer peripheral surface 131b of a valve body 130, and that blocks communication between a pressure-changing chamber and the atmosphere. The seal member 170 has a tubular base part 171, a seal part 172 that is provided to an inner peripheral surface 171a of the base part 171 and that slides against the outer peripheral surface 131b to block communication between a pressure-changing chamber R2 and the atmosphere, a circumferential recess 174 that is provided to an outer peripheral surface 171b of the base part 171 and that allows the seal part 172 to be displaced in a radial direction while the seal part 172 is sliding against the outer peripheral surface 131b, and a circumferential contact part 175 that is provided to the outer peripheral surface 171b of the base part 171 and that presses against the inner peripheral surface 112c.

Description

Negative pressure booster

The present invention relates to a negative pressure type booster.

Conventionally, for example, a negative pressure booster disclosed in Patent Document 1 below is known. This conventional negative pressure booster is provided with a seal member that is attached to the tip of a cylindrical portion provided so as to be able to communicate with the shell and that is in sliding contact with the outer peripheral surface of the valve body. The seal member has an inner peripheral seal portion that is disposed inside the cylindrical portion and is in sliding contact with the outer peripheral surface of the valve body on the inner peripheral surface. Further, the seal member has an outer peripheral seal portion that is in sliding contact with the inner peripheral surface of the cylindrical portion on the outer peripheral surface. In the conventional negative pressure booster, the seal member hermetically blocks the inside and the outside of the shell by the inner peripheral seal portion and the outer peripheral seal portion.

JP-T-3-502565 Publication

However, in the above-described conventional negative pressure type booster, the inner peripheral seal portion (protrusion) is worn by moving the valve body relative to the seal member, and the seal surface of the inner peripheral seal portion with respect to the valve body There is a possibility that the pressure is lowered and the airtightness cannot be maintained. Considering such wear of the inner seal part, if the seal surface pressure of the inner seal part (projection) is set high during assembly, even if wear occurs on the inner seal part (projection), the minimum Although airtightness can be maintained, a high sealing surface pressure increases sliding resistance with the valve body during assembly or until wear occurs on the inner peripheral seal portion (protrusion). As a result, in the conventional negative pressure booster described above, there is a concern that the responsiveness deteriorates during the operation in which the valve body moves relatively, and the operational feeling perceived by the driver via the brake pedal.

The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a negative pressure type booster capable of maintaining hermeticity without hindering operation feeling and responsiveness when a seal member is operated.

In order to solve the above problems, the invention of the negative pressure booster according to claim 1 includes a hollow booster shell, a constant pressure chamber that communicates the inside of the booster shell with a negative pressure source, and the negative pressure source or A movable partition wall that is hermetically partitioned and movable in a variable pressure chamber that can communicate with the atmosphere, and a cylindrical portion that is connected at one end so as to communicate with the variable pressure chamber of the booster shell and open at the other end to the atmosphere A cylindrical valve body that is inserted so as to be relatively movable with respect to the movable partition and moves together with the movable partition, a valve mechanism that is housed in the valve body and switches inflow of negative pressure or atmospheric pressure into the variable pressure chamber, and valve body An input member that is provided so as to be relatively movable in the inside thereof, inputs an operating force, an output member that outputs a propulsive force of the valve body, a pressure contact portion provided inside the cylindrical portion, and an outer peripheral surface of the valve body, Interchangeable between the transformer room A negative pressure booster having a circumferential seal member that blocks communication with the atmosphere, the seal member being provided on the cylindrical base and the inner peripheral surface of the base, Projected toward the outer peripheral surface and slidably contacted, a circumferential protrusion that blocks communication between the variable pressure chamber and the atmosphere, and a state where the protrusion is slidably contacted with the outer peripheral surface of the valve body. In the direction along the axis, a circumferential and concave gap portion that forms a gap with the pressure contact portion so as to allow displacement of the protrusion in the radial direction orthogonal to the direction of the axis of the base portion And a circumferential contact portion that is provided on the outer peripheral surface of the base portion and is in pressure contact with the pressure contact portion.

According to this, in the state where the seal member is interposed between the pressure contact portion and the outer peripheral surface of the valve body, the protrusion of the seal member can be displaced in the radial direction by the gap portion. Thereby, it is suppressed that the seal surface pressure in a protrusion becomes high too much, and it is suppressed that the sliding resistance accompanying the movement of a valve body becomes large. Further, the protrusion is displaced in the radial direction, whereby the contact portion is pressed toward the pressed contact portion. For this reason, in the situation where wear occurs in the protrusion and the seal surface pressure decreases, the contact portion exhibits a restoring force against the pressing, and the sealing surface pressure of the protrusion is appropriately maintained by this restoring force. Accordingly, since the seal surface pressure at the protrusion is appropriately maintained, the seal member can maintain the airtightness without hindering the operation feeling and the responsiveness during the operation of the negative pressure booster. .

It is the schematic which shows the structure of the brake device provided with the negative pressure type booster which concerns on embodiment of this invention. FIG. 2 is an overall view showing a configuration of the negative pressure booster of FIG. 1. It is sectional drawing which shows the assembly | attachment state of the sealing member of FIG. It is sectional drawing which shows the sealing member of FIG. It is sectional drawing for demonstrating the state before the assembly | attachment of the sealing member of FIG. It is sectional drawing for demonstrating the state before abrasion after the assembly | attachment of the sealing member of FIG. It is sectional drawing for demonstrating the state after abrasion after the assembly | attachment of the sealing member of FIG. It is sectional drawing which shows the sealing member which concerns on the modification of embodiment. It is sectional drawing which shows the assembly | attachment state of the sealing member which concerns on the modification of embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments and modifications, the same or equivalent parts are denoted by the same reference numerals in the drawings. Each figure used for explanation is a conceptual diagram, and the shape of each part may not necessarily be exact.

The negative pressure booster 100 of this embodiment constitutes a vehicle brake device 10 as shown in FIG. The vehicle brake device 10 includes a cylinder mechanism 20. The cylinder mechanism 20 includes a master cylinder 21,

master pistons

22 and 23, and a master reservoir 24. The

master pistons

22 and 23 are slidably disposed in the master cylinder 21. The

master pistons

22 and 23 partition the master cylinder 21 into a first master chamber 21a and a second master chamber 21b. The master reservoir 24 is a reservoir tank having a conduit communicating with the first master chamber 21a and the second master chamber 21b. The master reservoir 24 and the

master chambers

21a and 21b are communicated or blocked by the movement of the

master pistons

22 and 23.

The cylinder mechanism 20 includes a wheel cylinder 25, a wheel cylinder 26, a wheel cylinder 27, and a wheel cylinder 28. The wheel cylinder 25 is disposed on the left rear wheel RL of the vehicle. The wheel cylinder 26 is disposed on the right rear wheel RR of the vehicle. The wheel cylinder 27 is disposed on the left front wheel FL of the vehicle. The wheel cylinder 28 is disposed on the right front wheel FR of the vehicle. The master cylinder 21 and the wheel cylinders 25 to 28 are connected via an actuator 30. As a result, each of the wheel cylinders 25 to 28 applies a braking force to the left rear wheel RL, the right rear wheel RR, the left front wheel FL, and the right front wheel FR. In addition, although detailed description is abbreviate | omitted, the actuator 30 is comprised from the pipe line of illustration abbreviation, an electric pump, a solenoid valve, a non-return valve, etc.

In the vehicle brake device 10, when the driver depresses the brake pedal 11, the pedaling force is boosted by the negative pressure booster 100 airtightly connected to the master cylinder 21, and the master piston 22 in the

master cylinder

21, 23 is pressed. Thereby, the same master cylinder pressure is generated in the first master chamber 21a and the second master chamber 21b. The master cylinder pressure is transmitted to the wheel cylinders 25 to 28 via the actuator 30.

As shown in FIG. 2, the negative pressure booster 100 includes a hollow booster shell 110, and the movable partition wall 120 and the valve body 130 are assembled to the booster shell 110 so as to be movable in the front-rear direction. It has been. The inside of the booster shell 110 is communicated with a constant pressure chamber R1 communicating with a negative pressure source (for example, an intake manifold of an engine not shown) at the front and a negative pressure source or the atmosphere at the rear by a movable partition 120. Is divided into a variable pressure chamber R2.

The booster shell 110 includes a front shell member 111 and a rear shell member 112 formed of, for example, iron, aluminum, resin (reinforced plastic), or the like. The front shell member 111 is formed with a negative pressure introduction port 111a for communicating the constant pressure chamber R1 with a negative pressure source. The rear shell member 112 is provided with a cylindrical portion 112a through which the valve body 130 is inserted so as to be relatively movable in the front-rear direction along the direction of the axis J. The cylindrical portion 112a is connected so that one end communicates with the variable pressure chamber R2, and the other end is open to the atmosphere. Further, the cylindrical portion 112a is directed outward at a radial direction orthogonal to the direction of the axis J at the opening end of the other end, more specifically, an angle of 0 ° to 90 ° with respect to the axis J. The flange portion 112b is extended so as to have. As will be described later, the flange portion 112b locks the seal member 170 and the boot 160.

Further, a check valve 113 is provided at the negative pressure introduction port 111a. The check valve 113 is configured to permit air communication from the constant pressure chamber R1 side to the negative pressure source side and to block air communication from the negative pressure source side to the constant pressure chamber R1 side. Yes.

Further, the booster shell 110 has tie rod bolts 114 penetrating the front shell member 111 and the rear shell member 112 in two places in the radial direction. In FIG. 2, only one tie rod bolt 114 is shown. The two tie rod bolts 114 support the master cylinder 21 on the front shell member 111 side. Therefore, the retainer 115 is disposed between the inner surface 111 b of the front shell member 111 and the enlarged diameter portion 114 a of the tie rod bolt 114. The booster shell 110 has a rear bolt 116 that penetrates the rear shell member 112 in an airtight manner. The rear bolt 116 is fixed to the vehicle body (for example, a cowl) of the vehicle.

The movable partition 120 is provided in the booster shell 110 so as to be movable in the front-rear direction along the direction of the axis J of the valve body 130. The movable partition 120 includes an annular plate member 121 and an annular diaphragm 122 supported by the plate member 121. The plate member 121 is made of metal (for example, iron) or resin, and faces a flange portion 131a (described later) of the valve body 130 on the front side (front shell member 111 side) with respect to the diaphragm 122. Be placed.

The diaphragm 122 is formed of an annular elastic member (for example, an annular rubber material) and can be expanded and contracted, and the outer peripheral edge is hermetically fixed to the booster shell 110 (the front shell member 111 and the rear shell member 112). In addition, the inner peripheral edge is hermetically fixed to the valve body 130 together with the plate member 121. Specifically, as shown in FIG. 2, the diaphragm 122 includes an outer peripheral bead portion 122a, an inner peripheral bead portion 122b, and a seat portion 122c. The outer peripheral bead portion 122 a is provided in an annular shape on the outer peripheral edge of the diaphragm 122, and is airtightly held at the connection portion between the front shell member 111 and the rear shell member 112. The inner peripheral bead portion 122 b is annularly provided on the inner peripheral edge of the diaphragm 122 and is airtightly fixed to the outer peripheral surface 131 b of the valve body 130 together with the plate member 121. The sheet part 122c connects the outer peripheral bead part 122a and the inner peripheral bead part 122b to each other.

As shown in FIG. 2, the tubular valve body 130 is inserted so as to be relatively movable with respect to the tubular portion 112 a of the booster shell 110 (more specifically, the rear shell member 112), and is integrated with the movable partition wall 120. Next, the vehicle moves forward toward the front shell member 111 and moves backward toward the rear shell member 112. The valve body 130 includes a main body 131 made of resin and formed in a cylindrical shape. The main body part 131 has a flange part 131a extending outward in the radial direction at the opening end part on the front side (one end side). The main body 131 is engaged with a return spring S provided between the flange 131 a and the front shell member 111, and is urged rearward by the return spring S.

The main body 131 is assembled at the central portion to the cylinder portion 112a of the rear shell member 112 of the booster shell 110 so as to be relatively movable in the front-rear direction along the direction of the axis J. Further, a portion of the main body 131 (that is, the valve body 130) protruding outside the booster shell 110 (more specifically, the cylindrical portion 112a of the rear shell member 112) is covered and protected by a bellows-like boot 160. .

A pair of negative pressure communication paths 132 are provided inside the main body 131. In FIG. 2, only one negative pressure communication path 132 is shown. The negative pressure communication path 132 communicates with the constant pressure chamber R1 of the booster shell 110 at the front end, and communicates with the inside of the main body 131 at the rear end. In addition, the input shaft 141 and the plunger 142 are assembled in the main body 131 so as to be coaxial, and the valve mechanism 150 and the filter member 147 are assembled so as to be coaxial. Furthermore, a reaction member 144 made of an elastic member (for example, a rubber material) and an output shaft 145 are assembled in the main body 131 in front of the plunger 142 so as to be coaxial.

An input shaft 141 serving as an input member is provided in the valve body 130 (main body 131) so as to be relatively movable in the front-rear direction along the direction of the axis J, and inputs an operating force. To be connected to the connecting portion of the plunger 142 in an articulated manner. The input shaft 141 is connected to the brake pedal 11 via a yoke (not shown) by a screw portion provided at the rear end, and is configured to receive a pedal force acting on the brake pedal 11 as an operation force toward the front. Yes. The input shaft 141 is urged rearward by a spring engaged with the valve mechanism 150.

The plunger 142 is in contact with the central portion of the rear surface of the reaction member 144 at the tip 142a. The plunger 142 engages with the key member 143 in an annular groove formed in the central portion. Furthermore, the plunger 142 is provided with an annular atmospheric valve seat in the valve mechanism 150 at the rear end. The key member 143 has a function of restricting the movement of the plunger 142 in the front-rear direction with respect to the main body 131 of the valve body 130 and a movement limit position of the valve body 130 with respect to the booster shell 110 (returning back of the valve body 130 to the rear) (Position) is a member having a function of defining.

The reaction member 144 is accommodated in the rear cylindrical portion 145a of the output shaft 145, and is assembled to the main body 131 of the valve body 130 together with the rear cylindrical portion 145a of the output shaft 145. The reaction member 144 is pressed by the tip end portion 142a of the plunger 142 while being accommodated in the rear cylindrical portion 145a, so that the central portion of the rear surface bulges and deforms toward the front.

The output shaft 145 serving as an output member outputs the driving force of the valve body 130, and although not shown, the

master pistons

22 and 23 of the master cylinder 21 are pushed at the tip. Further, the output shaft 145 transmits the reaction force received from the

master pistons

22 and 23 of the master cylinder 21 to the reaction member 144 during the braking operation.

The valve mechanism 150 is disposed inside the valve body 130 and switches inflow of negative pressure or atmospheric pressure into the variable pressure chamber R2. The valve mechanism 150 includes a negative pressure valve seat integrally formed at the rear end portion of the negative pressure communication path 132 in the main body portion 131 of the valve body 130, and an atmospheric valve seat integrally formed at the rear end portion of the plunger 142. I have. The valve mechanism 150 includes a cylindrical valve body 151 disposed so as to be coaxial with the atmospheric valve seat. The valve body 151 includes an annular mounting portion and a cylindrical movable portion that is integrally formed with the mounting portion and is movable along the direction of the axis J. The attachment portion of the valve body 151 is airtightly assembled in the main body 131 of the valve body 130 and is held by the main body 131 by the annular member 146.

The movable portion of the valve body 151 is a negative pressure control valve that constitutes a negative pressure valve that communicates or blocks between the constant pressure chamber R1 and the variable pressure chamber R2 together with the negative pressure valve seat by being seated or separated from the negative pressure valve seat. With parts. The movable portion of the valve body 151 is an atmospheric control valve portion that constitutes an atmospheric valve that communicates or blocks between the variable pressure chamber R2 and the atmosphere together with the atmospheric valve seat by being seated or separated from the atmospheric valve seat. Have

Further, as shown in FIGS. 2 and 3, the negative pressure booster 100 includes an inner peripheral surface 112 c of the cylindrical portion 112 a as a pressure contact portion of the rear shell member 112 and an outer peripheral surface 131 b of the main body portion 131 of the valve body 130. And a circumferential seal member 170 interposed therebetween. The seal member 170 is assembled to the cylindrical portion 112a and blocks communication between the variable pressure chamber R2 and the atmosphere.

The seal member 170 is made of an elastic material (for example, a rubber material) and has a cylindrical base 171 as shown in FIGS. 3 and 4. The base portion 171 has an outer diameter that is set so as to have a tightening margin with the inner peripheral surface 112c of the cylindrical portion 112a as the pressed contact portion, and has an inner diameter that is larger than the outer diameter of the main body portion 131. . The base portion 171 is provided with a seal portion 172 as a protrusion on the inner peripheral surface 171a side, and before and after the seal portion 172 along the direction of the axis J (that is, sandwiching the seal portion 172). A) a guide part 173 is provided. Further, the base 171 is provided with a circumferential recess 174 as a gap on the outer peripheral surface 171b side, and before and after the circumferential recess 174 along the direction of the axis J (that is, the circumferential recess 174). A contact portion 175 is provided (so as to sandwich 174).

Here, the formation position of the seal portion 172 and the formation position of the circumferential recess 174 with respect to the base portion 171 are more adjacent to each other in the radial direction perpendicular to the axis J of the base portion 171 arranged coaxially with the main body portion 131. Specifically, as shown in FIG. 3, the protruding end portion of the seal portion 172 and the valley bottom portion of the circumferential recess 174 are provided so as to exist on a virtual line Js orthogonal to the axis J. Thereby, the circumferential recessed part 174 is provided outside in the radial direction perpendicular to the axis J with respect to the seal part 172.

The seal portion 172 as a protrusion is formed so as to protrude from the inner peripheral surface 171a toward the outer peripheral surface 131b of the main body 131 of the valve body 130, and is in sliding contact with the outer peripheral surface 131b of the main body 131. The seal portion 172 has an inner diameter that is smaller than the outer diameter of the main body portion 131, and blocks communication between the variable pressure chamber R <b> 2 and the atmosphere (outside) while the main body portion 131 is inserted. Further, the seal portion 172 has a substantially U-shaped cross section in a plane including the axis J, and has a vertex.

The guide portion 173 includes a first guide portion 173a and a second guide portion 173b that are positioned forward and backward with respect to the seal portion 172 in the direction along the axis J and extend along the axis J. The first guide portion 173a is provided in front of the seal portion 172 in the direction along the axis J on one end side of the base portion 171, that is, on the variable pressure chamber R2 side. The first guide portion 173 a protrudes from the inner peripheral surface 171 a of the base portion 171 toward the main body portion 131 so as to be in sliding contact with the outer peripheral surface 131 b of the main body portion 131 of the valve body 130, and compared with the outer diameter of the main body portion 131. And has a slightly smaller inner diameter. As a result, the first guide portion 173a swings in the radial direction of the main body 131 when the main body 131 is relatively moved in the front-rear direction along the direction of the axis J with the main body 131 inserted. The main body 131 is guided along the direction of the axis J. Further, the first guide portion 173a is provided with a negative pressure communication groove 173a1 that communicates the space formed between the seal portion 172 and the first guide portion 173a and the variable pressure chamber R2.

The second guide portion 173b is provided on the other end side of the base portion 171, that is, on the air side, behind the seal portion 172 in the direction along the axis J. The second guide portion 173 b is formed so as to extend in the direction along the axis J of the valve body 130, and has an inner diameter that is slightly smaller than the outer diameter of the main body portion 131. Thereby, the second guide portion 173b suppresses the swing of the main body portion 131 in the radial direction when the main body portion 131 relatively moves in the front-rear direction in a state where the main body portion 131 is inserted, and the main body portion 131 is axially moved. Guide along the direction of J. The second guide portion 173b is provided with an atmosphere communication groove 173b1 that communicates the space formed between the seal portion 172 and the second guide portion 173b and the atmosphere.

The circumferential recess 174 as a gap is provided in a concave shape from the outer peripheral surface 171b toward the seal portion 172 in a circumferential and concave shape. Here, as shown in FIG. 3 and FIG. 4, the seal portion 172 as the protrusion and the circumferential recess 174 as the gap portion have a cross-sectional shape in a plane including the axis J symmetrical with respect to the radial direction, It is provided so as to have a similar shape (substantially the same shape) as the portion 172.

The outer diameter of the abutting portion 175 is set larger than the inner diameter of the cylindrical portion 112a so as to be in pressure contact with the inner peripheral surface 112c of the cylindrical portion 112a as the pressed portion. Thus, the contact portion 175 presses the seal portion 172 toward the outer peripheral surface 131b of the main body portion 131 of the valve body 130 via the base portion 171 in a state where the seal member 170 is assembled to the cylindrical portion 112a. It has become.

Further, the seal member 170 includes an extending portion 176 and a locking portion 177 provided integrally with the base portion 171. The extension portion 176 is provided to be annular at one end side of the base portion 171, that is, the end portion on the side of the variable pressure chamber facing the variable pressure chamber R2, and in a state where the seal member 170 is assembled to the cylindrical portion 112a, It is arranged between the inside of the booster shell 110 (rear shell member 112) and the key member 143. The extended portion 176 is continuous in the circumferential direction as a slit provided along the circumferential direction so as to reduce the rigidity of the extended portion 176 in a state of being fixed inside the booster shell 110 (rear shell member 112). A plurality of concave grooves 176a are provided. The concave groove 176a as a slit is provided so as to face the inside of the booster shell 110 (rear shell member 112). Accordingly, the concave groove 176a is formed in the rear shell based on the pressure difference between the atmospheric pressure and the negative pressure when the variable pressure chamber R2 becomes negative pressure and the pressure inside the groove becomes negative pressure when the variable pressure chamber R2 communicates with the atmosphere. It is adsorbed and fixed inside the member 112.

The locking portion 177 is provided to be annular at the other end side of the base portion 171, that is, the atmosphere-side end portion, and the flange portion of the cylindrical portion 112 a in a state where the seal member 170 is assembled to the cylindrical portion 112 a. Locked to 112b. As shown in FIG. 3, the locking portion 177 protrudes toward the flange portion 112 b along the direction of the axis J from the virtual line Js along the radial direction passing through the contact position P that contacts the flange portion 112 b. It has a protrusion 177a. As a result, the locking portion 177 has the protruding portion 177a engaged with the flange portion 112b, and when the main body portion 131 of the valve body 130 moves forward in the direction along the axis J, the seal member 170 is moved to the cylindrical portion 112a. To prevent it from being pulled into the interior.

In the negative pressure booster 100 configured as described above, when the driver depresses the brake pedal 11, the input shaft 141 and the plunger 142 are positioned with respect to the main body 131 of the valve body 130 as shown in FIG. It moves forward from the original position and non-returning position. Thereby, the negative pressure control valve portion is seated on the negative pressure valve seat, the atmospheric valve seat is separated from the atmospheric control valve portion, and the variable pressure chamber R2 communicates with the atmosphere. Therefore, the atmosphere flows into the variable pressure chamber R2 through the filter member 147, the inside of the valve body 151, the gap with the atmosphere valve seat, the communication path provided in the main body 131, and the like. As a result, a pressure difference is generated between the constant pressure chamber R1 and the variable pressure chamber R2 so that the pressure in the constant pressure chamber R1 increases, and the movable partition 120 is moved forward (front shell) as the input shaft 141 moves forward. The member 111 moves toward the flange 131a of the main body 131.

In this case, the movable partition 120 moves forward (toward the front shell member 111) together with the main body 131 of the valve body 130 by engaging with a flange 131a provided on the main body 131 of the valve body 130. . As a result, the output shaft 145 moves forward (toward the front shell member 111) to press the

master pistons

22 and 23 of the master cylinder 21, and the master cylinder pressure is transmitted to the wheel cylinders 25 to 28 via the actuator 30. Is done.

On the other hand, when the stepping operation on the brake pedal 11 is released by the driver, the input shaft 141 and the plunger 142 return to the return non-operating position (original position) shown in FIG. When the input shaft 141 and the plunger 142 are returned to the original positions, the atmospheric control valve portion is seated on the atmospheric valve seat, and the negative pressure control valve portion is separated from the negative pressure valve seat. In this case, the communication between the variable pressure chamber R2 and the atmosphere is blocked, and the constant pressure chamber R1 and the variable pressure chamber R2 communicate with each other, whereby the variable pressure chamber R2 communicates with the negative pressure source.

In this case, air is supplied from the variable pressure chamber R2 to the constant pressure chamber R1 through the communication passage provided in the main body 131 of the valve body 130, the gap between the negative pressure control valve portion and the negative pressure valve seat, the negative pressure communication passage 132, and the like. Is sucked. As a result, since the pressure in the variable pressure chamber R2 and the pressure in the constant pressure chamber R1 become equal, the movable partition 120 and the valve body 130 are moved rearward by the urging force of the return spring S, and the output shaft 145 is moved rearward. Thereby, the pressing of the

master pistons

22 and 23 of the master cylinder 21 by the output shaft 145 is released, and the master cylinder pressure is reduced.

Here, when the driver depresses the brake pedal 11 or releases the depressing operation, the valve body 130 has an axis line with respect to the cylindrical portion 112a and the seal member 170 locked to the cylindrical portion 112a. Relative movement along the direction of J. In this case, since the seal portion 172 of the seal member 170 is in sliding contact with the outer peripheral surface 131b of the main body portion 131 of the valve body 130, sliding resistance is generated as the valve body 130 moves.

Incidentally, the seal member 170 is provided with a circumferential recess 174 as a gap on the outer peripheral surface 171b of the base 171 so as to be adjacent to the seal 172 as a protrusion along the radial direction. The circumferential recess 174 allows the seal portion 172 to be displaced in the radial direction. As a result, as shown in FIG. 5, before the seal member 170 is assembled to the cylindrical portion 112a, the seal portion 172 is not pressed by the outer peripheral surface 131b of the main body portion 131 and is not displaced in the radial direction. As a result, the maximum length L of the valley portion in the radial direction of the circumferential recess 174 is the largest.

As shown in FIG. 6, the seal member 170 is assembled between the cylindrical portion 112a and the valve body 130 (main body portion 131). More specifically, the seal portion 172 is not yet worn at an initial stage. In the state, the seal portion 172 is pressed outward in the radial direction by the outer peripheral surface 131b of the main body portion 131 and is displaced in the radial direction. As a result, the maximum length L of the circumferential recess 174, that is, The gap with the inner peripheral surface 112c is the smallest. Thus, when the length L of the circumferential recess 174 is reduced, in other words, when the seal member 172 is displaced in the radial direction, the seal member 172 is sealed in the state where the seal member 170 is assembled. The surface pressure is suppressed from becoming excessively high, and airtightness that blocks communication between the variable pressure chamber R2 and the atmosphere inside the cylindrical portion 112a is exhibited.

Here, when the seal portion 172 is pressed outward in the radial direction by the outer peripheral surface 131b of the main body portion 131, the contact portion 175 is pressed toward the inner peripheral surface 112c of the cylindrical portion 112a. Thus, the contact portion 175 pressed against the inner peripheral surface 112c of the cylindrical portion 112a is pressed against the outer peripheral surface 131b of the main body 131 as shown in FIGS. An elastic restoring force F acting on is generated.

When the main body 131 of the valve body 130 is repeatedly relatively moved in the front-rear direction, the seal portion 172 that is in sliding contact with the outer peripheral surface 131b of the main body 131 may be worn, and the seal surface pressure at the seal portion 172 may be reduced. . When the seal portion 172 is worn, as shown in FIG. 7, the seal portion 172 is pressed toward the outer peripheral surface 131 b of the main body portion 131 by the elastic restoring force F of the contact portion 175. Thereby, even if it is a case where abrasion arises in seal part 172, the seal surface pressure in seal part 172 is maintained appropriately.

Here, even when the valve body 130 moves along the direction of the axis J by the extending portion 176 and the locking portion 177, the seal member 170 is maintained in a state of being fixed to the cylindrical portion 112a. In this case, the extending portion 176 has a recessed groove 176a as a slit adsorbed inside the rear shell member 112 due to a pressure difference between negative pressure and atmospheric pressure, and the recessed groove 176a has reduced rigidity. On the other hand, the locking portion 177 prevents the protruding portion 177a from being engaged with the flange portion 112b and the seal member 170 from being pulled into the cylindrical portion 112a. Accordingly, the contact portion 175 has the influence that the extension portion 176 and the locking portion 177 fix the seal member 170 to the cylindrical portion 112a regardless of the movement of the main body portion 131 of the valve body 130. The elastic restoring force F can be applied to the seal portion 172 without receiving it. When wear occurs in the seal portion 172 in this way, the length L, that is, the gap, of the circumferential recess 174 increases in accordance with the amount of wear that occurs in the seal portion 172.

As can be understood from the above description, the negative pressure booster 100 according to the present embodiment uses the hollow booster shell 110 (the front shell member 111 and the rear shell member 112) and the booster shell 110 as a negative pressure source. A constant pressure chamber R1 that communicates with the variable pressure chamber R2 that can communicate with the negative pressure source or the atmosphere, and a movable partition wall 120 that is movable in an airtight manner, and the variable pressure chamber R2 of the booster shell 110 so as to communicate with each other. A cylindrical valve body 130 that is connected to one end and connected to the cylindrical portion 112a that is open to the atmosphere so that the other end is movable, and moves integrally with the movable partition wall 120, and is accommodated in the valve body 130. The valve mechanism 150 that switches inflow of negative pressure or atmospheric pressure into the variable pressure chamber R2 and the valve body 130 are provided so as to be movable relative to each other and input an operating force. An input shaft 141 as an input member, an output shaft 145 as an output member that outputs the propulsive force of the valve body 130, an inner peripheral surface 112c as a pressure contact portion provided inside the cylindrical portion 112a, and the valve body 130. A negative pressure type booster including a circumferential seal member 170 interposed between the outer peripheral surface 131b and the communication between the variable pressure chamber R2 and the atmosphere. The base portion 171 and the inner peripheral surface 171a of the base portion 171 are provided so as to protrude toward the outer peripheral surface 131b of the valve body 130 (main body portion 131) and slidably contact with each other to block communication between the variable pressure chamber R2 and the atmosphere. A seal portion 172 as a circumferential protrusion and an outer peripheral surface 171b of the base portion 171 are provided, and the seal portion 172 is in sliding contact with the outer peripheral surface 131b of the valve body 130 (main body portion 131). A circumferential concave portion as a circumferential and concave gap portion that forms a gap with the inner peripheral surface 112c so as to allow displacement of the seal portion 172 in the radial direction orthogonal to the direction of the axis J of the portion 171 174, and a circumferential contact portion 175 that is provided on the outer peripheral surface 171b of the base portion 171 and is in pressure contact with the inner peripheral surface 112c. Have.

According to this, in a state where the seal member 170 is interposed between the inner peripheral surface 112c of the cylinder portion 112a and the outer peripheral surface 131b of the main body portion 131 of the valve body 130, the seal portion 172 of the seal member 170 has a circumferential shape. The recess 174 can be displaced in the radial direction. Thereby, it is suppressed that the seal surface pressure in the seal part 172 becomes excessively high, and the sliding resistance accompanying the movement of the valve body 130 in the direction along the axis J is suppressed.

Further, the contact portion 175 is pressed toward the inner peripheral surface 112c of the cylindrical portion 112a by the displacement of the seal portion 172 in the radial direction. For this reason, in a situation where the seal portion 172 wears and the seal surface pressure decreases, the contact portion 175 exhibits an elastic restoring force F against the pressure, and the seal surface pressure of the seal portion 172 is appropriately maintained by this restoring force. Is done. Therefore, since the seal surface pressure in the seal portion 172 is appropriately maintained, the seal member 170 has a simple configuration and does not hinder the operation feeling and responsiveness during the operation of the negative pressure booster 100. Airtightness can be maintained.

In this case, the circumferential concave portion 174 is provided outside in the radial direction of the seal portion 172, and is initially assembled between the inner peripheral surface 112c of the cylindrical portion 112a and the outer peripheral surface 131b of the main body portion 131 of the valve body 130. In this state, the maximum length L in the radial direction of the circumferential recess 174 is the smallest.

According to this, in a state where the seal member 170 is interposed between the inner peripheral surface 112c of the cylindrical portion 112a and the outer peripheral surface 131b of the main body 131 of the valve body 130 (assembled state), the seal portion 172 is , It can be reliably displaced in the direction along the radial direction. As a result, the length L in the radial direction of the circumferential recess 174 in the case where the seal member 172 is not yet worn in the initial stage of assembly of the seal member 170 and in the case where the seal member 172 is worn. By changing so that it may become large from an initial state, it can suppress that the seal surface pressure of the seal part 172 changes. Therefore, the seal member 170 can maintain airtightness without hindering the operation feeling and responsiveness.

In these cases, the seal portion 172 and the circumferential recess 174 have a cross-sectional shape in a plane including the axis J symmetrical with respect to the radial direction, and have a similar shape (substantially the same) as the seal portion 172.

According to this, in a state where the seal member 170 is interposed between the inner peripheral surface 112c of the cylindrical portion 112a and the outer peripheral surface 131b of the main body 131 of the valve body 130 (assembled state), the seal portion 172 is When pressed against the outer peripheral surface 131b, the contact portion 175 can be pressed evenly, and the contact portion 175 can equally apply an elastic restoring force to the seal portion 172. Thereby, it can suppress that uneven wear arises in the seal part 172, and can maintain the seal | sticker surface pressure of the seal part 172 favorably. Therefore, airtightness can be maintained over a long period of time.

Further, in these cases, the seal member 170 is positioned forward and backward with respect to the seal portion 172 in the direction along the axis J, is provided on the inner peripheral surface 171a of the base portion 171 and extends along the axis J. Circumferential guide portions 173 (first guide portion 173a and second guide portion 173b) that guide the valve body 130 that is in sliding contact with the outer peripheral surface 131b of the valve body 130 (main body portion 131) and moves relative to the cylindrical portion 112a. Have

According to this, the guide part 173 (the first guide part 173a and the second guide part 173b) has a valve body 130 (main body part 131) that moves relative to the cylinder part 112a along the direction of the axis J in the radial direction. Can be suppressed. Thereby, it can suppress that the seal surface pressure of the seal part 172 changes (decreases), and can maintain favorable airtightness.

Further, in these cases, the cylindrical portion 112a has a circumferential flange portion 112b extending outward in the radial direction at the other end, and the seal member 170 is opposed to the atmosphere of the base portion 171. It has the latching | locking part 177 extended toward the outward in radial direction in the atmospheric | air-end side part of the side to carry out, and latches to the flange part 112b. In this case, the flange portion 112b extends with an angle larger than 0 ° and smaller than 90 ° with respect to the direction along the axis J.

According to these, the locking portion 177 is locked to the flange portion 112b of the cylindrical portion 112a extending outward in the radial direction, so that the valve body 130 (main body portion 131) is in the direction of the axis J. When moving forward toward the variable pressure chamber R2, the seal member 170 can be prevented from moving forward (withdrawn) together with the valve body 130. Thereby, since the sealing member 170 is fixed with respect to the cylinder part 112a and the contact part 175 can provide the elastic restoring force F to the sealing part 172, favorable airtightness can be maintained.

Further, the flange portion 112b is extended outward in the radial direction, more specifically, extending so as to have an angle larger than 0 ° and smaller than 90 ° with respect to the direction along the axis J. Can be provided. Accordingly, for example, the flange portion 112b can be easily formed as compared with the case where the flange portion 112b is provided inward in the radial direction, and the manufacturing cost of the negative pressure booster 100 can be reduced. . Further, since the flange portion 112b extends outward in the radial direction, the seal member 170 can be easily assembled.

In this case, the locking portion 177 has a protruding portion 177a that protrudes toward the flange portion 112b along the direction of the axis J from the imaginary line Js along the radial direction passing through the contact position P that contacts the flange portion 112b. .

According to this, when the seal member 170 is going to move forward together with the valve body 130, the protruding portion 177a can be engaged with the flange portion 112b. Thereby, it is possible to more reliably prevent the seal member 170 from moving forward (withdrawn) together with the valve body 130. Therefore, since the seal member 170 is securely fixed to the cylindrical portion 112a, it is possible to maintain good airtightness.

Further, in these cases, the seal member 170 is provided at the end of the base 171 facing the variable pressure chamber R2 on the side of the variable pressure chamber, and the inside of the booster shell 110 (rear shell member 112) and the interior of the rear shell member 112. And a key member 143 that restricts the movement of the valve body 130 in the direction along the axis J. The extension portion 176 is disposed inside the rear shell member 112. A concave groove 176a is provided as a slit facing the surface.

According to this, the extending portion 176 is fixed (adsorbed) to the rear shell member 112 by the concave groove 176a, and the valve body 130 (main body portion 131) advances toward the variable pressure chamber R2 in the direction of the axis J. Alternatively, the seal member 170 can be prevented from moving forward or backward together with the valve body 130 when moving backward from the variable pressure chamber R2. Thereby, since the sealing member 170 is fixed with respect to the cylinder part 112a, it can hold | maintain favorable airtightness. Further, the concave groove 176a can reduce the rigidity of the extending portion 176. Thereby, the contact part 175 can give the elastic restoring force F with respect to the seal part 172 in the state in which the seal member 170 was assembled | attached to the cylinder part 112a.

The implementation of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.

For example, in the above embodiment, the seal portion 172 and the circumferential recess 174 of the seal member 170 are provided so as to be symmetrical with respect to the radial direction. Instead, as shown in FIG. 8, a seal portion 178 as a circumferential protrusion that is asymmetric with respect to the radial direction is, for example, a so-called lip shape extending from the inner peripheral surface 171 a of the base portion 171 ( It can also be a tongue. In this case, in order to maintain an appropriate seal surface pressure when the lip-shaped seal portion 178 is worn, the circumferential recess 174 corresponds to the connection position between the inner peripheral surface 171a and the lip-shaped seal portion 178. Provided. As a result, the seal surface pressure is maintained because the seal portion 178 is pressed toward the outer peripheral surface 131b of the main body 131 of the valve body 130 by the elastic restoring force F of the contact portion 175, as in the above embodiment. be able to.

Further, in the above embodiment, the concave groove 176 a provided in the extending portion 176 of the seal member 170 is opposed to the inside of the rear shell member 112 of the booster shell 110 and is fixed (adsorbed) inside the rear shell member 112. . Instead, as shown in FIG. 9, the concave groove 176 a is provided so as to face the key member 143, so that the key member 143 comes into contact with the inside of the seal member 170 and the rear shell member 112. The hitting sound can be reduced.

Further, in the above embodiment, the extending portion 176 is provided with the recessed groove 176a provided so as to reduce the rigidity of the extending portion 176 in a state of being fixed (adsorbed) inside the booster shell 110 (rear shell member 112). It was made to extend continuously in the circumferential direction. It can replace with this and can also provide the ditch | groove 176a as a slit so that it may extend intermittently in the circumferential direction. In this case, the extended portion 176 can be fixed (adsorbed) to a part of the groove 176a with respect to the key member 143. Therefore, the same effect as in the above embodiment can be obtained.

In the above embodiment and the above-described modification, the seal portion 172 has a shape having a substantially U-shaped cross section in the plane including the axis J, and the seal portion 178 has a cross section in the plane including the axis J. A lip shape (tongue shape) was formed. Instead of this, it is also possible to make the inner side (the surface in sliding contact with the outer peripheral surface 131b of the main body 131) along the axis line J in the radial direction of the seal portion 172. Thereby, it can suppress that an operation feeling changes before and after the seal part 172 is worn.

Furthermore, in the said embodiment, the to-be-contacted part to which the contact part 175 of the sealing member 170 is press-contacted was used as the internal peripheral surface 112c of the cylinder part 112a. Instead, for example, when a cylindrical reinforcing member that holds the seal member 170 is hermetically disposed inside the cylindrical portion 112a, the pressed contact portion can be used as the reinforcing member. Even in this case, the same effect as the above-described embodiment can be obtained.

Claims

With a hollow booster shell,
A constant pressure chamber that communicates with the interior of the booster shell to a negative pressure source, and a movable partition wall that is movable in an airtight manner in a variable pressure chamber that can communicate with the negative pressure source or the atmosphere;
One end of the booster shell is connected so as to communicate with the variable pressure chamber, and the other end is inserted so as to be relatively movable with respect to the cylindrical portion opened to the atmosphere, and moves integrally with the movable partition. A valve body;
A valve mechanism housed in the valve body and switching inflow of negative pressure or atmospheric pressure into the variable pressure chamber;
An input member that is provided so as to be relatively movable inside the valve body and inputs an operating force;
An output member for outputting the propulsive force of the valve body;
A circumferential seal member interposed between a pressure contact portion provided inside the cylindrical portion and an outer peripheral surface of the valve body, and blocking the communication between the variable pressure chamber and the atmosphere. Negative pressure booster,
The sealing member is
A tubular base,
A circumferential projection provided on an inner circumferential surface of the base, projecting and slidingly contacting the outer circumferential surface of the valve body, and blocking the communication between the variable pressure chamber and the atmosphere;
Provided on the outer peripheral surface of the base, and allowing the protrusion to be displaced in a radial direction perpendicular to the direction of the axis of the base in a state where the protrusion is in sliding contact with the outer peripheral surface of the valve body. A circumferential and concave gap that forms a gap with the pressure contact portion, and
A circumferential abutting portion that is positioned forward and backward with respect to the gap portion in a direction along the axis, and is provided on the outer peripheral surface of the base portion and press-contacts the pressure-contacting portion. Pressure booster.
The gap is
The maximum length in the radial direction of the gap portion is the smallest in the initial state that is provided outside in the radial direction of the protrusion and is assembled between the pressure contact portion and the valve body. The negative pressure type booster according to claim 1.
The protrusion and the gap are
The negative pressure type booster according to claim 1 or 2, wherein a cross-sectional shape in a plane including the axis is symmetrical with respect to the radial direction and is similar to the protrusion.
The sealing member is
It is located forward and backward with respect to the protrusion in the direction along the axis, is provided on the inner peripheral surface of the base, extends along the axis, and slidably contacts the outer peripheral surface of the valve body. The negative pressure type booster according to any one of claims 1 to 3, further comprising a circumferential guide portion that guides the valve body that moves relative to the cylindrical portion.
The cylindrical portion is
It has a circumferential flange extending outward in the radial direction at the other end,
The sealing member is
2. The device according to claim 1, further comprising a locking portion that extends outward in the radial direction at an atmospheric air side end portion of the base portion that faces the atmospheric air and that locks the flange portion. The negative pressure type booster according to claim 4.
The locking portion is
The negative pressure type booster according to claim 5, further comprising a projecting portion projecting toward the flange portion along the direction of the axis rather than an imaginary line along the radial direction passing through a contact position in contact with the flange portion. apparatus.
The sealing member is
The valve body of the valve body in the direction along the axis in the inside of the booster shell and the inside of the booster shell A key member that restricts movement, and an extending portion disposed between the key member and
The extending portion is
The negative pressure type booster according to any one of claims 1 to 6, further comprising a slit facing the inside of the booster shell.