JPH0537894Y2 - - Google Patents

Description

[Detailed description of the invention] "Field of industrial application" The present invention relates to a brake booster, and more specifically, a key member that prevents a valve plunger constituting a valve mechanism from falling off from a valve body, and a key member that prevents the valve plunger from falling off from the valve body. The present invention relates to a retaining device for a key member of a brake booster, which includes a retaining member that prevents the key member from falling off from a valve.

"Prior Art" Conventionally, the following brake boosters are known. In other words, it consists of a valve body slidably provided within the shell, a valve mechanism disposed within the valve body that controls switching of the fluid circuit in response to forward and backward movement of the input shaft, and a part of this valve mechanism. , a valve plunger slidably provided on the valve body; a key member inserted through the valve body and engaged with the valve plunger to prevent the valve plunger from falling off from the valve body; and a C-shape surrounding the valve body. a retaining member that is formed in a shape and that engages engaging portions formed at both ends of the key member with the key member to prevent the key member from falling off from the valve body; a bifurcated first engaging part that engages with the valve body; a bent part bent into a crank shape from the base of the first engaging part and formed in an arc shape along the circumferential direction of the valve body; A C-shaped circular arc portion extending along the circumferential direction of the valve body from the end of the bent portion, and a C-shaped arc portion located at both ends of the bent portion in the circumferential direction and engaged with the engaging portion of the retaining member. A structure comprising a second engaging portion that fits together is known.

"Problem to be Solved by the Invention" By the way, in the conventional brake booster described above, the second engaging part of the key member is constituted by the outer periphery of both ends of the arc-shaped bent part. Ori,
In this case, both engaging portions of the hook-shaped retaining member are caused to engage with each other by their own elasticity. Therefore, when the key member is urged in the direction of falling off from the valve body with a relatively strong force, both engaging portions of the retaining member are expanded, thereby preventing the retaining member from coming off. There was a risk that both engaging portions of the member would fall off from the second engaging portion of the key member, and that the key member would fall off from the valve body.

"Means for Solving the Problems" In view of the above circumstances, the present invention provides the brake booster described above, in which the second engaging portion of the key member is constituted by a concave portion recessed toward the center of the valve body. , the engaging portion of the retaining member is constituted by a convex portion that engages with the recess, and the second engaging portion of the key member and the engaging portion of the retaining member engage with each other, The key member has an inclined surface that is inclined with respect to the direction in which the key member falls off from the valve body, and when the key member is biased in the direction that the key member falls off from the valve body, both of the retaining members engage with each other by the inclined surface. The parts are arranged close to each other.

"Operation" According to such a configuration, even if the key member is biased in the direction of falling off from the valve body, both engaging parts of the retaining member come close to each other due to the above-mentioned inclined surface, thereby further preventing the key member from falling off from the valve body. This will forcefully engage the key member. Therefore, the key member can be reliably prevented from falling off from the valve body by the retaining member.

"Example" The present invention will be explained below with reference to the illustrated example.
In FIG. 1, a center plate 3 is provided within a shell composed of a front shell 1 and a rear shell 2, and a valve body 4 is disposed to slidably penetrate the center plate 3 and rear shell 2.

The valve body 4 has a center plate 3.
The front power piston 5 is located on the front shell 1 side, and the rear power piston 6 is located on the rear shell 2 side.
A pair of constant pressure chambers A, A' and a variable pressure chamber B, It forms a section with B′.

A valve mechanism 11 is provided within the valve body 4, and this valve mechanism 11 communicates with a constant pressure passage 12 communicating with the constant pressure chamber A', a variable pressure passage 13 communicating with the variable pressure chamber B', and further communicating with the atmosphere. Pressure passage 14
It is now possible to switch and control the communication state between the two.

The constant pressure chamber A' communicates with the other constant pressure chamber A via a constant pressure passage 15, and the constant pressure chamber A communicates with an intake manifold (not shown) via a negative pressure introduction pipe 16 attached to the front shell 1. .
Further, the variable pressure chamber B' communicates with the other variable pressure chamber B via a variable pressure passage 17.

Furthermore, a hub 2 is attached to the shaft portion of the valve body 4.
1 is fixed, and the valve mechanism 1 is fixed in the hub 21.
A valve plunger 22 constituting a part of the engine 1 is slidably fitted therein, and the right end of the valve plunger 22 is connected to an input shaft 23 that is linked to a brake pedal (not shown). The left end of the valve plunger 22 is opposed to the right end surface of a reaction disk 24 in the hub 21, and the left end surface of the reaction disk 24 is connected to the right end surface of a push rod 25 that is slidably fitted in the hub 21. It is in contact with the

The tip of the push rod 25 passes through the seal member 26 and projects outward from the front shell 1, and is interlocked with a piston of a master cylinder (not shown).

A key member 31 that prevents the valve plunger 22 from coming off the hub 21 is interlocked with the valve plunger 22 by passing through the valve body 4 and the hub 21 from the radial direction thereof, and
The retaining member 32 prevents the valve body from falling off from the valve body 4.

As shown in FIGS. 2 and 3, the key member 31 includes a bifurcated first engaging portion 31a that communicates with the valve body 4 and the hub 21 and engages with the small diameter portion of the valve plunger 22; It includes a bent part 31b bent into a crank shape from the base of the first engaging part 31a, and a C-shaped arc part 31c extending from the distal end of the bent part 31 along the circumferential direction of the valve body 4. There is.

The bent portion 31b is formed in an arc shape along the circumferential direction of the valve body 4, and second engaging portions 31d with which the retaining member 32 engages are formed on both sides of the bent portion 31b. This second engaging portion 31d
are in opposite directions with respect to the direction in which the key member 31 comes off from the valve body 4 (arrow direction in FIG. 2),
Further, the two second engaging portions 31d have inclined surfaces that are inclined so that adjacent sides thereof are toward the center of the valve body 4, thereby forming a recess that is recessed toward the center of the valve body.

On the other hand, the retaining member 32 is a C-shaped main body portion 3 made of spring steel and surrounding the valve body.
2a, and second engagement portions, i.e., recesses 31 formed on both ends of the main body portion 32a on the side of the key member 31.
Each of these engaging portions 32b is formed of a wedge-shaped protrusion with its tip protruding toward the center of the valve body 4, and each protrusion is formed along each of the second engaging portions 31d of the key member 31 and has an inclined surface that engages with them.

Therefore, according to the above configuration, each of the second engaging portions 31d of the key member 31 and the engaging portion 32b of the retaining member 32 are engaged with each other by the inclined surfaces of both members. I come to do it. Therefore, even if the key member 31 is biased in the direction of falling off, the distance between the engaging parts 32b of the retaining member 32 is reduced, so that the engaging parts 31d, 32
b does not come off, and therefore the locking member 32 can reliably prevent the key member 31 from falling off from the valve body 4.

"Effect of the invention" As described above, according to the invention, even if the key member is biased in the direction of falling off from the valve body, the retaining member reliably prevents the key member from falling off the valve body. The effect of being able to do this is obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
This figure is a front view showing the main part of FIG. 1, and FIG. 3 is a sectional view taken along the - line in FIG. 2. 1...Front shell, 2...Rear shell, 4
... Valve body, 11 ... Valve mechanism, 12, 15
... Constant pressure passage, 13, 17... Variable pressure passage, 14...
... Pressure passage, 22 ... Valve plunger, 23 ... Input shaft, 25 ... Push rod, 31 ... Key member, 31d ... Engagement part (recess), 32 ... Removal prevention member, 32b ... Engagement part (Protrusion).

Claims (1)

[Scope of claim for utility model registration] A valve body slidably provided within the shell,
a valve mechanism disposed within the valve body that controls switching of the fluid circuit according to forward and backward movement of the input shaft;
A valve plunger that constitutes a part of the valve mechanism and is slidably provided on the valve body, and a key that is inserted through the valve body and engages with the valve plunger to prevent the valve plunger from falling off from the valve body. and a retaining member formed in a C-shape surrounding the valve body and configured to engage engaging portions formed at both ends of the key member with the key member to prevent the key member from falling off from the valve body. , the key member includes a bifurcated first engaging portion that engages with the valve plunger, and a crank-shaped first engaging portion that is bent from the base of the first engaging portion and has an arc shape along the circumferential direction of the valve body. a C-shaped circular arc portion extending along the circumferential direction of the valve body from the distal end of the bent portion;
A brake booster comprising second engaging portions located at both ends of the bent portion in the circumferential direction and engaging with the engaging portion of the retaining member, wherein the second engaging portion of the key member a concave portion recessed toward the center of the valve body, an engaging portion of the retaining member comprising a convex portion that engages with the concave portion, and a second engaging portion of the key member and the retaining member. The portion of the member that engages with the engaging portion has an inclined surface inclined with respect to the direction in which the key member falls off from the valve body, and when the key member is biased in the direction in which it falls off from the valve body. A key member slip-out prevention device for a brake booster, characterized in that both engaging portions of the slip-off prevention member are brought close to each other by the inclined surface.