JP2016222116A - Negative pressure type booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative pressure type booster capable of suppressing increase of sliding resistance between a valve body and a filter.SOLUTION: A negative pressure type booster includes: an air introduction path 221 which is divided by a valve body 22 and connects the air and an air valve V2; and a filter 5 which is arranged on the air introduction path 221 slidably on the valve body 22 and is formed of an insertion hole 51 inserting an input shaft member 31 therethrough. Therein, at least a part of an inner circumferential surface 51a of the insertion hole 51 is departed from the input shaft member 31 so as to communicate one side of the filter 5 with the other side thereof, in such a state that the valve body 22 and the input shaft member 31 are parallel to each other or in the maximum inclined state of the input shaft member 31.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a negative pressure type booster.

  Generally, a negative pressure type booster is an air introduction path that is partitioned in a valve body and connects the atmosphere and the atmosphere valve, and a filter that is slidably disposed in the atmosphere introduction path and that filters the air flowing into the valve body. And an input member that moves forward in response to a driver's brake operation (pedal operation). An insertion hole through which the input member is inserted is formed at the axial center of the filter. The insertion hole is formed in the same shape (a perfect circle) as the shape of the input member so that the entire inner peripheral surface of the filter constituting the insertion hole is in contact with the outer peripheral surface of the input member. Such a negative pressure booster is described in, for example, Japanese Patent Application Laid-Open No. 2014-125134.

JP 2014-125134 A

  Here, when the input member is configured to be inclined with respect to the axis of the valve body in the arrangement state or the movement process, the filter is pressed against the valve body by the inclined input member. This increases the sliding resistance between the valve body and the filter. Due to the increase of the sliding resistance, in the operation of the negative pressure type booster, the movement of the valve body can be delayed at the initial stage of the operation, and the valve body can move forward from the middle of the operation. That is, there is a risk of giving the driver a discontinuous pedal feeling due to an increase in sliding resistance.

  This invention is made in view of such a situation, and it aims at providing the negative pressure type booster which can suppress the increase in the sliding resistance between a valve body and a filter.

  The negative pressure type booster of the present invention includes a movable partition that divides the inside of the housing into one negative pressure chamber and the other variable pressure chamber, and is assembled to the housing so as to be able to advance and retreat, and is connected to the movable partition at one end. A valve body, an input shaft member disposed in the valve body so as to be movable back and forth with respect to the valve body, and moving in response to an external operation force; and a relative position of the valve body and the input shaft member An atmospheric valve that communicates and blocks between the variable pressure chamber and the atmosphere, and a negative valve that communicates and blocks between the negative pressure chamber and the variable pressure chamber according to the relative position of the valve body and the input shaft member. A pressure valve, an air introduction path that is partitioned by the valve body and communicates the atmosphere and the air valve, and is arranged in the air introduction path so as to be slidable on the valve body, and the input shaft member is inserted through a central portion. Insertion hole is formed And at least a part of the inner peripheral surface of the insertion hole is inclined most when the valve body and the input shaft member are parallel or when the input shaft member is not operating and operating. In the maximum inclination state, the filter is separated from the input shaft member so that the one side and the other side of the filter communicate with each other.

  According to the negative pressure type booster of the present invention, at least a part of the inner peripheral surface of the insertion hole formed in the filter is separated from the input shaft member. For this reason, when the input shaft member is inclined with respect to the valve body, the input shaft member is moved by the space formed in the separated portion or by the deformation of the contact portion that is easily deformed by the separated portion. The radially outward force is absorbed. Therefore, the force with which the filter presses the valve body is reduced, and an increase in sliding resistance between the valve body and the filter is suppressed.

It is sectional drawing which shows the structure of the negative pressure type booster of a 1st Example. It is sectional drawing which shows the structure in the valve body of a 1st Example. It is explanatory drawing for demonstrating the brake pedal of a 1st Example. It is the front view seen from the axial direction which shows the filter of a 1st Example. It is explanatory drawing for demonstrating the relationship between an input and time. It is the front view seen from the axial direction which shows the filter of a 2nd Example. It is the front view seen from the axial direction which shows the filter of a 3rd Example. It is sectional drawing which shows the filter of 3rd Example.

  Below, the negative pressure type booster concerning an embodiment of the present invention is explained based on a drawing. Note that the filter 5 in FIGS. 1 and 2 is represented by a cross section taken along line II in FIG. 4, 6, and 7, the contact surface 52 represents only the inner peripheral line. In the description, one side (the left side in the figure) of the negative pressure booster is the front, the other side (the right side in the figure) is the rear, and the vertical direction in the figure is the vertical direction.

<First Example>
As shown in FIGS. 1 and 2, the negative pressure booster 1 mainly includes a housing 10, a power piston 20, a boot 19, an input member 30, a negative pressure valve V1, an atmospheric valve V2, and a retainer. 36 and a filter 5.

  A power piston 20 is assembled to the housing 10 so as to be movable in the front-rear direction. The power piston 20 includes a movable partition wall 21 and a valve body 22. The inside of the housing 10 is partitioned by a movable partition wall 21 into a front negative pressure chamber R1 and a rear variable pressure chamber R2. The housing 10 includes a front shell 11 disposed in front and a rear shell 12 assembled to a rear end portion of the front shell 11. The front shell 11 is provided with a negative pressure introduction pipe 11a for constantly communicating the negative pressure chamber R1 with a negative pressure source (for example, an intake manifold of an engine not shown). The front shell 11 is airtightly assembled with a rear end portion of a brake master cylinder (not shown). A piston (not shown) of the brake master cylinder projects rearward from the cylinder body and enters the negative pressure chamber R1, and is configured to be pushed forward by a distal end portion 35a of an output shaft 35 described later. ing. The housing 10 includes a mounting bolt 12a that hermetically penetrates the front shell 11 and the rear shell 12, and a mounting bolt 12b that hermetically penetrates the rear shell 12. The mounting bolts 12a and 12b fix the housing 10 to a stationary member (that is, a vehicle body) (not shown). The mounting bolt 12a supports a brake master cylinder (not shown) in the front.

  The movable partition wall 21 is composed of an annular plate 21a and an annular diaphragm 21b. The movable partition wall 21 is installed in the housing 10 so as to be movable in the front-rear direction (the axial direction of the power piston 20). The diaphragm 21b is airtightly sandwiched between the housing 10 by an annular outer peripheral bead portion 21a1 formed on the outer peripheral edge thereof. The diaphragm 21b is hermetically fixed to the outer peripheral portion of the valve body 22 together with the inner peripheral portion of the plate 21a by an annular inner peripheral bead portion 21a2 formed on the inner peripheral edge thereof.

  The valve body 22 is a resin hollow body connected to the inner peripheral portion of the movable partition wall 21. The valve body 22 is airtight and longitudinally (power piston 20) in the rear shell 12 of the housing 10 at an intermediate portion formed in a cylindrical shape. It is assembled so that it can move in the axial direction). The valve body 22 is urged rearward by a return spring 13 interposed between the valve body 22 and the front shell 11. The valve body 22 has a stepped shaft hole 22a penetrating in the front-rear direction. The rear portion of the shaft hole 22a constitutes an air introduction path 221 that connects a later-described vent hole 19a and the air valve V2. That is, the air introduction path 221 is formed in the valve body 22. In other words, the valve body 22 defines the air introduction path 221. The air introduction path 221 is a flow path that connects the atmosphere and the atmosphere valve V2 through the vent hole 19a.

  Further, the valve body 22 is formed with a pair of negative pressure communication passages 22b (only one is shown in the figure). The negative pressure communication path 22b is a flow path whose rear end opens to the intermediate step portion A of the shaft hole 22a and whose front end opens to the negative pressure chamber R1. Further, the valve body 22 is formed with a key attachment hole 22c that is substantially orthogonal to the front portion of the shaft hole 22a and into which a key member 39 described later can be inserted from the outer periphery.

  The boot 19 is a rubber covering member having a bellows-shaped front part 191 and a rear part 192. The boot 19 covers a projecting portion of the valve body 22 to the outside of the housing 10. The front end portion of the front portion 191 is engaged with the rear end portion of the rear shell 12. The rear portion 192 is formed integrally with the rear end portion of the front portion 191 and is disposed at the rear end portion of the valve body 22 so as to close the rear end opening of the valve body 22. The rear part 192 is provided with a plurality of vent holes 19a. The ventilation hole 19a is a hole for communicating the atmosphere with the atmosphere introduction path 221.

  The input member 30 is a shaft-like member that moves forward in response to a brake operation. Specifically, the input member 30 includes an input shaft (corresponding to an “input shaft member”) 31 and a plunger (air valve) 32. The input shaft 31 and the plunger 32 are coaxially assembled in the shaft hole 22a. Further, in front of the plunger 32, a coupling member 33, a reaction member 34, and an output shaft (output member) 35 are coaxially assembled with respect to the shaft hole 22a.

  The input shaft 31 can be moved back and forth with respect to the valve body 22, and is connected to the receiving connection portion 32c of the plunger 32 in a joint shape by a spherical tip portion 31a. The input shaft 31 can swing with respect to the plunger 32. That is, the input shaft 31 can be inclined with respect to the axial direction of the plunger 32 and the valve body 22. For example, the input shaft 31 is inclined so that the rear end is upward in the initial state.

  As shown in FIG. 3, the input shaft 31 is connected to the brake pedal P via a yoke Y at a rear end screw portion (not shown). The input shaft 31 moves forward according to the operation of the brake pedal P. It can be said that the input shaft 31 is an input member for inputting a pedaling force to the master cylinder. The input shaft 31 is engaged with a return spring 37 via a retainer 36 locked to the intermediate step A, and is urged rearward by the return spring 37. The plunger 32 connected to the input shaft 31 is also urged rearward by the return spring 37. The retainer 36 is a cylindrical member provided coaxially with the input shaft 31 with respect to the input shaft 31. The retainer 36 is in contact with the filter 5. The retainer 36 presses the input shaft 31 (input member 30) and the filter 5 toward the rear portion 192 of the boot 19 by the urging force of the return spring 37. The abutment surface 52 of the retainer 36 and the filter 5 has an annular shape (see FIG. 4). The retainer 36 has a function of returning the input shaft 31 to the initial position.

  The plunger 32 is arranged so that the front end portion 32 a can come into contact with the center portion of the rear surface of the reaction member 34 via the connecting member 33. The front end portion 32 a is a portion that partially receives a reaction force from the reaction member 34 with respect to the output via the connecting member 33. An annular groove 32 b is formed at an intermediate portion of the plunger 32. The annular groove portion 32 b is formed so as to be engageable with the key member 39. An annular atmospheric valve seat 32d constituting the atmospheric valve V2 is formed at the rear end portion of the plunger 32. The output shaft 35 is assembled together with the reaction member 34 in the front end portion of the shaft hole 22a of the valve body 22 so as to be movable in the front-rear direction. The distal end portion 35a of the output shaft 35 is in contact with an engaging portion (concave portion) of a piston in the brake master cylinder so as to be able to be pushed. The output shaft 35 transmits the reaction force received from the piston of the brake master cylinder to the reaction member 34 during the braking operation.

  The key member 39 can be brought into contact with and separated from the valve body 22, the plunger 32, and the housing 10 (contact portion 12 c), and defines a movement amount along the axial direction of the plunger 32 with respect to the valve body 22. The key member 39 has a function of defining the forward / backward movement of the plunger 32 with respect to the valve body 22 and a function of defining a rearward movement limit position of the power piston 20 with respect to the housing 10 (an initial position of the valve body 22). Yes. The key member 39 is assembled so as to be movable relative to the valve body 22 and the plunger 32 in the axial direction by a required amount.

  The negative pressure valve V <b> 1 is a valve mechanism that communicates and blocks between the negative pressure chamber R <b> 1 and the variable pressure chamber R <b> 2 as the plunger 32 advances and retreats with respect to the valve body 22. In other words, the negative pressure valve V1 communicates and blocks between the negative pressure chamber R1 and the variable pressure chamber R2 in accordance with the relative positions of the valve body 22 and the input shaft 31 (input member 30). The negative pressure valve V1 includes a negative pressure valve portion 41b1 and a negative pressure valve seat 22d. The negative pressure valve portion 41 b 1 is a part of the valve body 41 disposed in the valve body 22.

  The valve body 41 is a cylindrical member as a whole disposed in the shaft hole 22a. The valve body 41 connects the fixed portion 41a assembled to the inner peripheral surface of the valve body 22, the movable portion 41b that can move relative to the fixed portion 41a in the axial direction, and the fixed portion 41a and the movable portion 41b. 41d. The movable portion 41b is disposed on the front side of the fixed portion 41a. The movable portion 41 b is biased forward by the compression spring 43. The compression spring 43 is a compressed spring whose front end is in contact with the movable portion 41b and whose rear end is in contact with the retainer 36, and is formed to have a smaller diameter toward the rear end. The outer peripheral side of the front end portion of the movable portion 41b constitutes the negative pressure valve portion 41b1. In other words, the negative pressure valve portion 41b1 is formed at the front end portion of the movable portion 41b. The movable portion 41b includes an elastic movable portion 41e made of an elastic material, and a metal movable portion 41f formed in an annular plate shape made of a metal material fixed to the rear surface of the elastic movable portion 41e. . The elastic movable part 41e is integrally connected to the connection part 41d.

  The negative pressure valve seat 22d is formed at the rear end of the negative pressure communication path 22b. In other words, the rear end portion of the negative pressure communication path 22b constitutes the negative pressure valve seat 22d. The state in which the negative pressure valve portion 41b1 is in contact (seat) with the negative pressure valve seat 22d means that the negative pressure valve V1 is closed, and the state in which the negative pressure valve portion 41b1 is separated (separated) from the negative pressure valve seat 22d is the opening of the negative pressure valve V1. Means.

  The atmospheric valve V2 is a valve mechanism that communicates and blocks between the variable pressure chamber R2 and the atmosphere (vent hole 19a) in accordance with the advancement and retreat of the plunger 32 with respect to the valve body 22. In other words, the atmospheric valve V2 communicates and blocks between the variable pressure chamber R2 and the atmosphere (vent hole 19a) according to the relative position of the valve body 22 and the input shaft 31 (input member 30). The atmospheric valve V2 includes an atmospheric valve portion 41b2 and an atmospheric valve seat 32d. The atmospheric valve portion 41b2 is a part of the valve body 41, and is formed on the inner peripheral side of the front end portion of the movable portion 41b. In other words, the inner peripheral side of the front end portion of the movable portion 41b constitutes the atmospheric valve portion 41b2. The atmospheric valve portion 41b2 is formed in an annular shape so as to come into contact with the entire circumference in the circumferential direction of the rear end surface (the atmospheric valve seat 32d) of the plunger 32 at the initial position. The atmospheric valve seat 32 d is formed in an annular shape at the rear end portion of the plunger 32. In other words, the rear end portion (flange portion) of the plunger 32 constitutes the atmospheric valve seat 32d. The state where the atmospheric valve portion 41b2 is in contact (sitting) with the atmospheric valve seat 32d means that the atmospheric valve V2 is closed, and the state where the atmospheric valve portion 41b2 is separated (separated) from the atmospheric valve seat 32d is the opening of the atmospheric valve V2. Means.

  The filter 5 is a member that filters air flowing into the valve body 22. The filter 5 is disposed in the air introduction path 221 so as to be slidable on the valve body 22. The filter 5 has an insertion hole 51 through which the input shaft 31 is inserted at the center. As shown in FIG. 4, at least a part of the inner peripheral surface 51a of the insertion hole 51 (that is, the inner peripheral surface of the filter 5) is in a state where the valve body 22 and the input shaft 31 are parallel (hereinafter referred to as “parallel state”). Or one side (front side) and the other side (rear side) of the filter 5 are separated from the input shaft 31 in a maximum inclination state. In other words, at least a part of the inner peripheral surface 51a of the insertion hole 51 is separated from the input shaft 31 so as to form the through passage 51c in the axial direction. The maximum inclination state is a state in which the input shaft 31 is inclined most with respect to the valve body 22 in a series of brake operations including non-operation and operation. For example, the input shaft 31 in the initial state (when the brake is not operated: when not operating) may be in the maximum tilt state, or the input shaft 31 at a position where the brake is being operated (when operating) is in the maximum tilt state. In some cases. This invention includes what is the said separation | spacing state in both a parallel state and a maximum inclination state. Further, the contour line of the insertion hole 51 in the cross section viewed from the axial direction of the filter 5 (cross section cut by a plane orthogonal to the axial direction) is the contact surface 52 of the retainer 36 and the filter 5 in the parallel state or the maximum inclined state. It is located on the input shaft 31 side (radially inside).

  In the first embodiment, at least in a parallel state, a part of the inner peripheral surface 51a of the insertion hole 51 (a part in the circumferential direction) is separated from the input shaft 31 so as to form the through passage 51c in the axial direction. . The outline of the insertion hole 51 in the cross section when the filter 5 is viewed from the axial direction has a non-circular shape. In other words, the outline of the insertion hole 51 viewed from one axial side or the other axial side of the input shaft 31 has a non-circular shape. A plurality of projecting portions 51 b projecting toward the input shaft 31 and abutting on the input shaft 31 are formed on the inner peripheral surface 51 a of the insertion hole 51. In the first embodiment, four protrusions 51b are formed at equal intervals on the inner peripheral surface 51a. All the protrusions 51b are in contact with the input shaft 31 in a parallel state. The protruding portion 51b can be said to be a part of the inner peripheral surface 51a. In FIG. 4, the protrusions 51b are formed on the inner peripheral surface 51a on the top, bottom, left and right. Four portions (separated portions) where the inner peripheral surface 51a of the insertion hole 51 and the input shaft 31 are separated are formed in the circumferential direction. The through passage 51c formed by the separated portion does not overlap (does not overlap) the vent hole 19a when viewed from the axial direction.

  According to the negative pressure type booster 1 of the first embodiment, a gap (separated portion) is formed between the insertion hole 51 and the input shaft 31 except for the protruding portion 51b. The protrusion 51b is easily deformed, and the influence of the deformation on the outer side in the radial direction is small compared to the case where the inner peripheral surface 51a is in full contact with the input shaft 31. For this reason, when the input shaft 31 is inclined with respect to the valve body 22, the radially outward force due to the inclination is absorbed by the deformation of the protruding portion 51 b, and the force with which the filter 5 presses the valve body 22 decreases. Thereby, the increase in the sliding resistance between the valve body 22 and the filter 5 is suppressed.

  For example, as shown in FIG. 5, by suppressing the increase in sliding resistance, it is possible to suppress the occurrence of input load fluctuations (see broken lines in the figure) even if the initial swing of the input shaft 31 is large. When the sliding resistance between the filter 5 and the valve body 22 is large, the movement of the valve body 22 is inhibited by the sliding resistance. Thereby, a time lag may occur between the advance of the movable partition wall 21 and the advance of the valve body 22 due to the opening of the atmospheric valve V2. Then, as shown by the broken line in FIG. 5, the input load may vary due to a sudden advance of the valve body 22. That is, there is a concern about deterioration of the brake feeling. However, according to the present embodiment, occurrence of such a phenomenon can be suppressed.

  Further, the contour line of the insertion hole 51 in the cross section viewed from the axial direction is located radially inward (on the input shaft 31 side) from the contact surface 52 of the retainer 36 and the filter 5 in the parallel state and / or the maximum inclined state. Therefore, the through passage 51c does not directly open to the atmosphere introduction passage 221, and the air flowing in from the vent hole 19a can be more reliably filtered by the filter 5.

  In addition, by forming the contour line of the insertion hole 51 into a non-circular shape, a separated portion can be easily formed with respect to the input shaft 31 whose outer shape viewed from the axial direction is a circular shape. Moreover, since the protrusion 51b is formed in the insertion hole 51, the positioning of the input shaft 31 during assembly is facilitated. In the first embodiment, since the plurality of projecting portions 51b are provided, positioning becomes easier. Further, the protruding portion 51b is more easily deformed than the inner peripheral surface 51a in the case of the entire circumference contact with the input shaft 31, and an increase in sliding resistance is effectively suppressed. Further, according to the present embodiment, it is only necessary to change the filter 5, and the application to the conventional apparatus is easy.

<Second Example>
The negative pressure type booster of the second embodiment differs from the first embodiment in the shape of the insertion hole 51. Therefore, the different parts will be described, and descriptions of other parts will be omitted. The drawings can refer to the drawings of the first embodiment.

  As shown in FIG. 6, in the second embodiment, the outline of the insertion hole 51 in the cross section when the filter 5 is viewed from the axial direction is elliptical. Specifically, the outline of the insertion hole 51 has an elliptical shape having a major axis in the vertical direction (the same direction as the inclination direction of the input shaft 31). That is, the separated portion (through passage 51 c) is positioned in the vertical direction of the input shaft 31, and the portion where the inner peripheral surface 51 a and the input shaft 31 are in contact is positioned in the left-right direction of the input shaft 31. The short diameter part (left and right part) in the elliptical shape of the insertion hole 51 is in contact with the input shaft 31, and the positioning effect of the input shaft 31 is exhibited.

  The contour line of the insertion hole 51 is located on the radially inner side (input shaft 31 side) with respect to the abutment surface 52 of the retainer 36 and the filter 5. Further, the insertion hole 51 is formed so that the inner peripheral surface 51 a of the separated portion and the input shaft 31 do not come into contact with each other in the assumed maximum inclination state of the input shaft 31.

  According to the negative pressure type booster of the second embodiment, the same effect as the first embodiment is exhibited. Furthermore, in the second embodiment, in the maximum inclination state, the inner peripheral surface 51a of the separated portion of the insertion hole 51 does not contact the input shaft 31, so that the filter 5 is pressed against the valve body 22 by the inclination of the input shaft 31. And increase in sliding resistance is more effectively suppressed.

  Note that, when the filter 5 is assembled, it may be arranged in the valve body 22 such that the major axis of the ellipse is other than the vertical direction. Even when the separated portion (through passage 51c) is located in a direction other than the vertical direction of the input shaft 31, the presence of the separated portion reduces the force with which the filter 5 is pressed against the valve body 22 when the input shaft 31 is inclined. Increase in dynamic resistance is suppressed. It is also conceivable that the filter 5 rotates and the position of the separated portion moves while the brake operation is performed. For example, during the brake operation, the filter 5 rotates so that the inclination direction of the input shaft 31 and the major axis direction of the insertion hole 51 are the same direction. It is effective that the separated portion is positioned in the inclination direction (vertical direction) of the input shaft 31 when the brake is operated.

<Third embodiment>
The negative pressure booster of the third embodiment differs from the first embodiment in the shape of the insertion hole 51. Therefore, the different parts will be described, and descriptions of other parts will be omitted. The drawings can refer to the drawings of the first embodiment.

  As shown in FIGS. 7 and 8, the entire inner peripheral surface 51a of the insertion hole 51 of the third embodiment is separated from the input shaft 31 in the parallel state. Furthermore, in the third embodiment, the outline of the insertion hole 51 in the cross section viewed from the axial direction has a perfect circular shape, similar to the outline of the input shaft 31 viewed from the axial direction. The diameter of the contour line of the insertion hole 51 is larger than the diameter of the input shaft 31 and smaller than the diameter of the contact surface 52. Further, the filter 5 is formed so that the inner peripheral surface 51a of the insertion hole 51 and the input shaft 31 do not contact each other in the maximum inclined state. That is, the diameter of the outline of the insertion hole 51 is set to a length that does not allow the inner peripheral surface 51a and the input shaft 31 to contact each other in the maximum inclination state. According to the negative pressure type booster of the third embodiment, the same effect as the second embodiment is exhibited. In addition, since the entire circumference of the insertion hole 51 is a separated portion (or because the outline is a perfect circle), the operator does not need to pay attention to the direction (arrangement direction) of the insertion hole 51 and the filter 5 is assembled. Is easy. However, the first embodiment and the second embodiment are superior in terms of positioning of the input shaft 31 during assembly. The cross-sectional view of the second embodiment is the same as FIG. 8, and FIG. 8 can be referred to.

<Others>
The present invention is not limited to the above embodiment. For example, the outline of the insertion hole 51 may be a polygon such as a rhombus. One protrusion 51 b may be formed on the inner peripheral surface 51 a of the insertion hole 51. Further, the protruding portion 51b may be formed at a part of the inner peripheral surface 51a in the axial direction, such as formed at the front end portion, the axial center portion, and / or the rear end portion of the inner peripheral surface 51a. In the second and third embodiments, the insertion hole 51 may be formed so that the inner peripheral surface 51a and the input shaft 31 come into contact with each other in the maximum inclined state or before the maximum inclined state. Even in this case, when the input shaft 31 is inclined, the input shaft 31 moves in the separated portion (in the through passage 51c), thereby suppressing an increase in sliding resistance. The mounting bolt 12a may be a separate member for the front and rear, and the negative pressure booster 1 may not be a tie rod type.

  The brake pedal P connected to the input shaft 31 from the outside may be a link type. In the case of the link type, the input shaft 31 is likely to be inclined, and the application of the present invention is more effective. Even when the input shaft 31 is inclined with respect to the valve body 22 at the initial position of the brake pedal P, the same effect as the above embodiment is exhibited, and the present invention is effective. Further, the filter 5 may be formed of a plurality of layers (separable or fixed) overlapping in the axial direction. Further, the retainer 36 may be formed with a through hole. The contact surface 52 may be a partially cut ring. Further, the through passage 51 c of the first embodiment may be formed so that the inner peripheral surface 51 a excluding the protruding portion 51 b does not contact the input shaft 31 in the maximum tilt state of the input shaft 31. Moreover, the some protrusion part 51b may be formed so that the penetration path 51c of a 1st Example may be located up and down (or up and down left and right). Also in this case, the insertion hole 51 may be formed so that the inner peripheral surface 51a excluding the protruding portion 51b and the input shaft 31 do not come into contact with each other when the input shaft 31 is in the maximum inclined state. Also by this, the positioning of the input shaft 31 and the reduction of the sliding resistance can be effectively realized.

(Summary)
The negative pressure type booster of the present embodiment can be described as follows. That is, the negative pressure type booster of the present embodiment is assembled with a movable partition wall 21 that divides the inside of the housing 10 into one negative pressure chamber R1 and the other variable pressure chamber R2, and is movably assembled to the housing 10 at one end. A valve body 22 connected to the movable partition wall 21, an input shaft member 31 that is disposed in the valve body 22 so as to be movable back and forth with respect to the valve body 22, and moves according to an operating force from the outside, And the other end member 192 formed with a vent hole 19a for communicating the inside of the valve body 22 and the atmosphere with the other end portion, and the variable pressure chamber R2 according to the relative position of the valve body 22 and the input shaft member 31. According to the relative position of the atmospheric valve V2 that communicates and blocks between the atmosphere (vent 19a) and the valve body 22 and the input shaft member 31, the negative pressure chamber R1 and the variable pressure chamber R2 communicate and block. Negative pressure valve 1, an air introduction path 221 that is partitioned by the valve body 22 and communicates the atmosphere (vent hole 19 a) and the atmosphere valve V 2, and is arranged in the air introduction path 221 so as to be slidable on the valve body 22. And a filter 5 having an insertion hole 51 through which the member 31 is inserted. At least a part of the inner peripheral surface 51a of the insertion hole 51 is in a state in which the valve body 22 and the input shaft member 31 are parallel or input. The shaft member 31 is spaced apart from the input shaft member 31 so that the one side and the other side of the filter 5 communicate with each other in the maximum tilted state where the shaft member 31 is not operated and is most tilted during operation.
Further, the negative pressure booster includes a cylindrical retainer 36 that is arranged coaxially with the input shaft member 31 and presses the input shaft member 31 and the filter 5 toward the other end member 192, from the axial direction of the filter 5. The contour line of the insertion hole 51 in the viewed cross section indicates that the retainer 36 and the filter are in the state in which the valve body 22 and the input shaft member 31 are parallel or in the maximum inclination state in which the input shaft member 31 is most inclined during non-operation and operation. 5 may be located closer to the input shaft member 31 than the abutment surface 52.
Further, the outline of the insertion hole 51 in the cross section viewed from the axial direction of the filter 5 may be non-circular. In addition, a protruding portion 51 b that protrudes toward the input shaft member 31 and contacts the input shaft member 31 may be formed on the inner peripheral surface 51 a of the insertion hole 51. Moreover, the outline of the insertion hole 51 in the cross section seen from the axial direction of the filter 5 may be elliptical.

DESCRIPTION OF SYMBOLS 1 ... Negative pressure type booster, 10 ... Housing, 11 ... Front shell, 12 ... Rear shell, 19 ... Boot, 192 ... Back part (other end member), 19a ... Vent hole, 21 ... Movable partition, 22 ... Valve body, 221 ... Air introduction path, 31 ... Input shaft (input shaft member), 32 ... plunger, 36 ... retainer, 5 ... filter, 51 ... insertion hole, 51a ... inner peripheral surface, 52 ... contact surface, R1 ... negative pressure chamber , R2 ... transformer room, V1 ... negative pressure valve, V2 ... atmospheric valve.

Claims (5)

A movable partition that partitions the housing into one negative pressure chamber and the other variable pressure chamber;
A valve body assembled to the housing so as to be movable forward and backward and connected to the movable partition at one end;
An input shaft member disposed in the valve body so as to be movable back and forth with respect to the valve body, and moving in accordance with an operating force from the outside;
According to the relative position of the valve body and the input shaft member, an atmospheric valve that communicates and blocks between the variable pressure chamber and the atmosphere;
A negative pressure valve that communicates and blocks between the negative pressure chamber and the variable pressure chamber according to the relative position of the valve body and the input shaft member;
An atmosphere introduction path that is partitioned by the valve body and communicates the atmosphere and the atmosphere valve;
A filter that is slidably disposed on the valve body and is disposed in the atmosphere introduction path, and a filter having an insertion hole through which the input shaft member is inserted in a central portion;
With
At least a part of the inner peripheral surface of the insertion hole is in a state where the valve body and the input shaft member are parallel, or in a maximum inclination state where the input shaft member is most inclined during non-operation and operation. A negative pressure booster that is spaced apart from the input shaft member so as to communicate one side and the other side. A cylindrical retainer disposed coaxially with the input shaft member and abutting against the filter;
The outline of the insertion hole in the cross section viewed from the axial direction of the filter is a state in which the valve body and the input shaft member are parallel, or a maximum inclination state in which the input shaft member is most inclined during non-operation and operation. 2. The negative pressure booster according to claim 1, wherein the negative pressure booster is located closer to the input shaft member than a contact surface between the retainer and the filter.   3. The negative pressure booster according to claim 1, wherein a contour line of the insertion hole in a cross section viewed from an axial direction of the filter has a non-circular shape.   The negative pressure type magnification according to any one of claims 1 to 3, wherein a protruding portion that protrudes toward the input shaft member and contacts the input shaft member is formed on an inner peripheral surface of the insertion hole. Force device.   The negative pressure booster according to any one of claims 1 to 3, wherein a contour line of the insertion hole in a cross section viewed from the axial direction of the filter has an elliptical shape.

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