阅读说明：本技术 活塞组件 (Piston assembly ) 是由 S·里奇 于 2019-08-27 设计创作，主要内容包括：本申请公开了一种用于气动制动系统的汽缸的活塞组件。该活塞组件包括：具有向外突出端部(111、112)的弹性环(110)；具有用于至少部分地接收弹性环(110)的外部圆周槽(122)的柱塞(120)；具有内部圆周槽(132)和开口(134)的外部活塞(130),内部圆周槽(132)适用于至少部分地接收弹性环(110),向外突出端部(111、112)布置在开口(134)中。弹性环(110)适于在弹性环(110)的默认状态下将柱塞(120)附接到外部活塞(130),在将向外突出的端部(131、132)相对彼此移动时,弹性环(130)移动到内部圆周槽(132)中或者另外一个圆周槽(122)中,直至使得柱塞(110)与外部活塞(120)能相互分开。(A piston assembly for a cylinder of a pneumatic braking system is disclosed. The piston assembly includes: an elastic ring (110) having outwardly projecting ends (111, 112); a plunger (120) having an outer circumferential groove (122) for at least partially receiving the resilient ring (110); an outer piston (130) having an inner circumferential groove (132) and an opening (134), the inner circumferential groove (132) being adapted to at least partially receive the resilient ring (110), the outwardly protruding end (111, 112) being arranged in the opening (134). The elastic ring (110) is adapted to attach the plunger (120) to the outer piston (130) in a default state of the elastic ring (110), the elastic ring (130) moving into the inner circumferential groove (132) or into the other circumferential groove (122) upon moving the outwardly protruding ends (131, 132) relative to each other until the plunger (110) and the outer piston (120) are allowed to separate from each other.)

1. A piston assembly for a cylinder of a pneumatic brake system,

characterized in that said piston assembly comprises:

-an elastic ring (110) having outwardly protruding ends (111, 112);

-a plunger (120) having an outer circumferential groove (122) for at least partially receiving the elastic ring (110);

-an outer piston (130) having an inner circumferential groove (132) and an opening (134), the inner circumferential groove (132) being adapted to at least partially receive the elastic ring (110), the outwardly protruding end portion (111, 112) being arranged in the opening (134),

wherein the resilient ring (110) is adapted to attach the plunger (120) to the outer piston (130) in a default state of the resilient ring (110), the resilient ring (110) moving into the inner circumferential groove (132) or the other circumferential groove (122) upon moving the outwardly protruding ends (111, 112) relative to each other until the plunger (120) and the outer piston (130) are separable from each other.

2. The piston assembly of claim 1,

the method is characterized in that:

the opening (134) of the outer piston (130) is adapted to define a structure (136) for applying forceps to move the outwardly projecting ends (111, 112) relative to each other.

3. The piston assembly of claim 2, wherein the piston is a single-piece piston,

the method is characterized in that:

the structure (136) for applying forceps is at least one of:

-a recess (136) at the opening (134) in the outer piston (130),

-one or more couplings for forceps at the ends (111, 112) of the elastic ring (110).

4. Piston assembly according to one of the preceding claims,

the method is characterized in that:

the opening (134) of the outer piston (130) is formed as a cutout portion extending from an axial end portion of the outer piston (130).

5. Piston assembly according to one of the preceding claims,

characterized in that said piston assembly comprises:

an inner piston (140) extending at least partially inside the outer piston (130) at an axial position opposite the plunger (120) and adapted to be coupled to the outer piston (130) to move axially together.

6. The piston assembly of claim 5, wherein the piston is a single-piece piston,

characterized in that said piston assembly comprises:

a spring (150) coupled between the plunger (120) and the inner piston (140) to provide axial pressure; and

the method is characterized in that:

the outer piston (130) and the inner piston (140) include abutments to limit relative axial movement due to the spring (150) and thereby provide axial coupling between the plunger (120) and the inner piston (140).

7. Piston assembly according to one of the preceding claims,

the method is characterized in that:

the plunger (120) includes a plunger body (124) and one or more tabs (126) to define the circumferential groove (122) between the plunger body (124) and the one or more tabs (126).

8. A piston assembly according to claim 7 when dependent on claim 6,

the method is characterized in that:

the one or more protrusions (126) are arranged to provide support for the spring (150).

9. A foot brake valve for a vehicle,

characterized in that the foot brake valve comprises:

a cylinder (160); and

the piston assembly of any one of the preceding claims, arranged in the cylinder (160) such that the plunger (120) and the outer piston (130) are axially movable together in the cylinder (160).

10. The foot brake valve according to claim 9,

characterized in that the foot brake valve comprises:

a cap (170) enclosing the cylinder (160) and a sleeve (180) adapted to move axially with the plunger (120), wherein the cap (170) extends within the sleeve (180) over the entire stroke of the plunger (120) to provide lateral guidance.

11. A vehicle, in particular a commercial vehicle, having a foot brake valve according to claim 9 or 10.

Technical Field

The present invention relates to a piston assembly for a cylinder, and in particular, to a piston stack design for a foot brake valve of a pneumatic brake system.

Background

These systems use foot brake valves to apply the correct pressurization upon request by the driver of the commercial vehicle. These valves comprise a different piston and at least one plunger, which are clamped to each other.

These different interacting components make assembly difficult, and there is a need for a design that allows for quick and cost-effective assembly and, if necessary, easy disassembly of the stack/assembly.

Disclosure of Invention

At least some of these problems are overcome by a piston assembly according to claim 1 and a foot brake valve according to claim 9. The dependent claims relate to further advantageous implementations of the subject matter of the independent claims.

The present invention relates to a piston assembly for a cylinder of a pneumatic brake system. The piston assembly includes an elastomeric ring having an outwardly projecting end, a plunger having an outer circumferential groove for at least partially receiving the elastomeric ring, and an outer piston having an inner circumferential groove and an opening. The inner circumferential groove is adapted to at least partially receive the resilient ring when the protruding end is located in the opening. The resilient ring is adapted to attach the plunger to the outer piston in a default state of the resilient ring. When the outwardly projecting ends are moved relative to each other, the elastic ring moves into the inner circumferential groove or into another circumferential groove until the plunger and the outer piston are allowed to separate from each other.

Axial direction may be defined as the direction of displacement/movement of the plunger inside the cylinder. The term "groove" shall include a recess or gap adapted to receive the resilient ring or a portion thereof. In particular, the circumferential groove may be realized as a recess formed in the body or as a gap between the two parts, as long as the groove can receive the elastic ring to enable the fixing of the respective component.

Optionally, the opening of the outer piston is adapted to define a structure for applying forceps to move the outwardly projecting ends relative to each other. For example, the structure for applying the forceps may be a recess at an opening in the outer piston, and/or one or more couplings for the forceps at the end of the elastic ring.

Alternatively, the opening of the outer piston is formed as a cutout portion extending from an axial end portion of the outer piston.

Optionally, the piston assembly further comprises an inner piston extending at least partially inside the outer piston at an axial position opposite the plunger. The inner piston is adapted to be coupled to the outer piston such that the two members move axially together. Additionally, the piston assembly may include a spring coupled between the plunger and the inner piston to provide axial compression. The outer piston and the inner piston may comprise abutments to limit relative axial movement due to the spring and thus provide axial coupling between the plunger and the inner piston. Since the outer piston and the plunger cannot move axially relative to each other in the default state of the resilient ring, the spring provides a biasing force that pushes the plunger and the inner piston away from each other.

Optionally, the plunger comprises a plunger body and one or more protrusions to define a circumferential groove between the plunger body and the one or more protrusions. One or more projections may be arranged to provide support for the spring. Optionally, the protrusion is an integral part of the plunger body. But it may also be a separate element arranged on the surface of the plunger facing the cylinder interior and held in abutment by the spring.

Embodiments of the present invention also relate to a foot brake valve for a vehicle, the foot brake valve including a cylinder and the piston assembly described above. The piston assembly is arranged in the cylinder such that the plunger is axially movable with the outer piston in the cylinder.

The foot brake valve may further comprise a cap for closing the cylinder and a sleeve adapted to move axially with the plunger. The cap may extend inside the sleeve over the full stroke of the plunger to provide lateral guidance.

Embodiments of the present invention also relate to a vehicle having the foot brake valve described above. The vehicle may be a commercial vehicle and the piston assembly may be part of a braking system of the vehicle.

Drawings

Some examples of the present system will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 shows a cross-sectional view through a piston assembly according to an embodiment of the invention.

Fig. 2 shows a perspective view of the piston assembly of fig. 1.

FIG. 3 illustrates a piston pack having a piston assembly for a foot brake valve according to another embodiment of the present invention.

Fig. 4 shows a cross-sectional view of the piston group of fig. 3 perpendicular to the axial displacement of the pistons.

Detailed Description

Fig. 1 shows a cross-sectional view through a piston assembly comprising an elastic ring 110, a plunger 120 defining an outer circumferential groove 122 for at least partially receiving the elastic ring 110, and an outer piston 130 having an inner circumferential groove 132 for at least partially receiving the elastic ring 110. Thus, the elastic ring 110 is arranged between the plunger 120 and the outer piston 130 to attach the two members to each other. Additionally, the piston assembly includes an inner piston 140 disposed inside the outer piston 130 and a spring 150 extending between the inner piston 140 and the plunger 120 to provide a biasing force that holds the inner piston 140 away from the plunger 120.

The plunger 120 includes a plunger body 124 and at least one protrusion 126, the protrusion 126 extending into the interior space of the outer piston 130 and providing a circumferential groove 122. The protrusion 126 may be formed integrally with the plunger body 124. However, according to other embodiments, the protrusion 126 may be a separate element formed as a step and defining the circumferential groove 122 at a radially outer position, and include a portion extending radially inward in the region between the spring 150 and the plunger body 124 such that the portion is pressed by the spring 150 onto the shoulder of the plunger body 124.

Fig. 2 shows a perspective view of a piston assembly with an outer piston 130 and an inserted plunger 120, which are joined together by an elastic ring 110 arranged between the plunger 120 and the outer piston 130. The outer piston 130 comprises an opening 134 into which the outwardly protruding ends 111, 112 of the resilient ring 110 protrude.

The resilient ring 110 is adapted to secure the plunger 120 to the outer piston 130 in a default state (e.g., an expanded state) of the resilient ring 110. As shown in fig. 1, the resilient ring 110 extends partially into the outer circumferential groove 122 and partially into the inner circumferential groove 132, whereby in this default state the plunger 120 is interlocked with the outer piston 130. Upon moving the outwardly projecting ends 111, 112 relative to each other, the resilient ring 110 moves into the outer circumferential groove 122 (when pressed together) or into the inner circumferential groove 132 (when pulled apart) to such an extent that the plunger 120 and the outer piston 130 can be separated from each other. The shoulder portion of the plunger body 124 may provide a cover over the outer piston 130.

FIG. 3 illustrates a piston pack having a piston assembly for an exemplary foot brake valve. The piston assembly with the resilient ring 110, the plunger 120, the outer piston 130 and the inner piston 140 is arranged inside a cylinder 160 closed by a cap 170 through which a stem portion of the plunger 120 extends. The plunger 120 is movable together with the outer piston 130 and the inner piston 140 in the axial direction M (linear displacement) relative to the cylinder 160. The cap 170 has an opening 175 for allowing linear displacement of the plunger 120 therethrough. More precisely, the plunger rod of the plunger 120 extends through the opening 175 and the shoulder portion (widened portion) is arranged in the inner space 162 of the cylinder 160.

The illustrated piston assembly also includes a sleeve 180. The sleeve 180 is disposed between the cap 170 and the cylinder 160 and also extends between the outer piston 130 and the cylinder 160. During linear displacement M through the interior space 162 of the cylinder 160, the sleeve 180 moves with the plunger 120 relative to the cap 170. The plunger 120 and the sleeve 180 cannot move relative to each other in the axial direction M, but can rotate relative to each other about the axial direction M. This axial coupling may be achieved by a slot/pin coupling structure 185 including, for example, a projection or projecting ring extending radially inward from the sleeve 180 and a corresponding recess or groove formed at the outer circumference of the plunger 120 (or its widening). The reverse could also be achieved, i.e. the groove/recess is formed in the sleeve 180 and the protrusion is formed on the plunger 120.

Optional sealing elements 137 may be formed between the cap 170 and the plunger 120, between the cap 170 and the cylinder 160, between the outer piston 130 and the cylinder 160, and between the inner piston 140 and the outer piston 130. During the linear displacement M of the plunger 120, these sealing elements 137 may be sealing rings that seal the inner space 162 against the outside.

Fig. 4 shows a cross-sectional view of the piston group of fig. 3 along a section a-a perpendicular to the axial displacement M. Thus, the cylinder 160 represents an outer housing in which the sleeve 180, the outer piston 130, the resilient ring 110, the outer circumferential groove 122, the protrusion 126, the spring 150, and the plunger body 124 are formed. The elastic ring 110 is formed such that the protruding ends 111, 112 extend radially outwards into the opening 134 of the outer piston 130 and the outer circumferential groove 122 remains partly empty.

A gap is provided between the outwardly projecting ends 111, 112. Thus, the two ends 111, 112 may be pushed together to push the resilient ring 110 into the outer circumferential groove 122 and out of the inner circumferential groove 132 of the outer piston 130. As a result, the plunger 120 can be separated from the outer piston 130. To simplify this decoupling, a recess 136 may be provided in the opening 134 of the outer piston 130, so that the outwardly projecting ends 111, 112 can be grasped with pliers and pushed together. It will be appreciated that decoupling of the outer piston 130 from the plunger 120 may be achieved when the resilient ring 110 in a default state leaves a portion of the inner circumferential groove 132 empty. The interlocking coupling can be opened by pulling the outwardly projecting ends 111, 112 apart (into the partially open inner circumferential groove 132).

Advantageous aspects of the embodiments may be summarized as follows:

the piston assembly may be part of a piston pack having a plunger 120, an outer piston 130, an inner piston 140, a spring 150, and an elastic ring 110. The piston set may be part of a foot brake valve and has the task of proportionally controlling and delivering the pressure of the first circuit of the commercial vehicle's pneumatic brake system with respect to the bias of the spring 150.

According to an embodiment of the present invention, a specially designed (steel) elastic ring 110 with 90 degree bent ends is used to couple the outer piston 130 to the plunger 120. These free ends of the elastic ring 110 may be sufficiently close to each other during the assembly process that the wires may be retracted inside the groove of the plunger 120 and both ends may be inserted inside the outer piston 130. The outer piston 130 is provided with an end-fittable opening 134 of the resilient ring 110 at the top side. The opening 134 is large enough to allow the resilient ring 110 to expand sufficiently in the groove of the outer piston 130 so that the two parts are locked together. The opening 134 in the outer piston 130 has side recesses 136 for gripping and tightening the ends of the elastic ring 110 using pliers and releasing the plunger 120 from the outer piston 130.

The specification and drawings merely illustrate the principles of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its scope.

Furthermore, although each embodiment may stand on its own as a separate example, it should be noted that the defined features may be combined differently in other embodiments, i.e. that a particular feature described in one embodiment may also be implemented in other embodiments. Such combinations are encompassed by the present disclosure unless a specific combination is not intended.

List of reference numerals:

110 elastic ring

111. 112 outwardly projecting end portion

120 plunger

122 outer circumferential groove

124 plunger body

126 plunger body projection

130 outer piston

132 inner circumferential groove

134 opening in the outer piston

136 Structure for applying forceps

137 sealing element

140 internal piston

150 spring

160 cylinder body

162 inner space

170 cover

175 opening in the lid

180 sleeve

185 slot/pin coupling arrangement

And (5) linearly displacing M.