JP2017101788A - Air cylinder and, exhaust brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent water from entering a cylinder body.SOLUTION: An air cylinder is provided that comprises: a cylinder body 21; a piston 22; a first hollow chamber 24 defined within the cylinder body 21 across the piston 22; a second hollow chamber 25 defined within the cylinder body 21 across the piston 22; a spring 26 energizing the piston 22 toward the second hollow chamber 25; a first air vent 27 formed penetrating in an outer wall on the side of the first hollow chamber 24, of the cylinder body 21; a cover member 30 having a cylinder wall part 31 having a larger diameter than the cylinder body 21, and also forming an air flow passage F communicating with the first air vent 27 between the cylinder body 21 and cylinder wall part 31; a second air vent 34 formed penetrating a lower-side wall part of the cylinder wall part 31; and a third air vent 35 formed penetrating another part different from the lower-side wall part of the cylinder wall part 31.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an air cylinder and an exhaust brake device including the air cylinder.

  2. Description of the Related Art Conventionally, an exhaust brake device has been put into practical use in which a shutter valve provided in an exhaust pipe is opened and closed to enhance a braking effect when using an engine brake. In a general exhaust brake device, a braking effect is obtained by closing a shutter valve with an air cylinder to close an exhaust passage and increasing an exhaust pressure.

  For example, in Patent Document 1, a single-acting air cylinder applicable to an exhaust brake device is provided with a vent hole on a rod protruding end side of a cylinder body, and a bottomed cylindrical cover member is fitted on the outer periphery of the cylinder body. A configuration is disclosed in which a drain hole is provided in the lower wall portion of the cover member and a through hole is provided in the side wall portion of the cover member, so that negative pressure is prevented from being generated in the normal pressure chamber when the piston is returned. ing.

JP-A-11-201112

  By the way, in the structure in which the drain hole is provided in the lower wall portion of the cover member as in the above-described prior art, for example, when the water is collected around the lower portion of the cover member and the drain hole is submerged, the exhaust brake is turned off. When the piston is returned by the above, negative pressure is generated in the cover member and the normal pressure chamber, and water sucked into the cover member from the drain hole may enter the cylinder body, thereby causing a failure. .

  In general, since the exhaust brake device is attached adjacent to an exhaust pipe extending in the longitudinal direction of the vehicle body, the air cylinder is also arranged such that its axial direction is the longitudinal direction of the vehicle body. For this reason, in the above prior art, the side wall portion of the cover member provided with the through hole comes to face the front of the vehicle body, and the water that is rolled up and scattered by the tire directly hits the through hole, and from the through hole to the inside of the cylinder body. Intrusion of water into the water may cause failure.

  The disclosed technology aims to effectively prevent water from entering the cylinder body.

  The disclosed air cylinder includes a hollow cylindrical cylinder body, a piston slidably accommodated in the cylinder body, a rod having one end fixed to the piston and the other end protruding from the cylinder body. A first hollow chamber defined on the rod side in the cylinder body across the piston, and a first hollow chamber defined on the opposite side of the first hollow chamber in the cylinder body across the piston. A second hollow chamber to be supplied; a spring which is housed in the first hollow chamber and biases the piston toward the second hollow chamber; and penetrates the outer wall of the cylinder body on the first hollow chamber side. The formed first vent hole and the cylindrical wall portion having a diameter larger than that of the cylinder main body, and the outer peripheral surface of the cylinder main body and the inner surface of the cylindrical wall portion are brought into contact with the outer peripheral surface of the cylinder main body. Between A cover member that forms an air flow path that communicates with the first vent hole; a second vent hole that is formed through the lower wall portion of the cylindrical wall portion to communicate the air flow path with the outside; and the cylindrical wall And a third vent hole penetratingly formed in another portion different from the lower side wall portion of the portion to communicate the air flow path with the outside.

  The front third vent hole may be formed as an elongated hole extending in the axial direction of the cylinder body.

  The cover member may be formed in a cylindrical shape, and the third ventilation hole may be provided in a lateral side wall portion where the cylindrical wall portion protrudes most in the lateral direction when the cover member is viewed in the axial direction.

  The disclosed exhaust brake device includes the air cylinder, a valve housing provided in an exhaust pipe, a shutter valve pivotally supported by the valve housing and capable of closing an exhaust passage, and the shutter valve. It is provided with the link mechanism which connects the said rod, and the bracket to which the said cylinder main body is attached.

  The exhaust pipe may be extended in the longitudinal direction of the vehicle body, and the cylinder body may be attached to the bracket with its axial center direction directed in the longitudinal direction of the vehicle body.

  The housing further includes an outer cover member that is formed in a housing shape having an open side surface, and that has an opening edge abutted against the bracket and accommodates at least a part of the link mechanism and the cylinder body therein. Also good.

  According to the disclosed technique, it is possible to effectively prevent water from entering the cylinder body.

It is the typical fragmentary sectional view which looked at the exhaust brake device which concerns on this embodiment upward. It is the typical perspective view which looked at the exhaust brake device concerning this embodiment from the side in the state where the outside cover member was removed. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is a figure explaining the flow of air when a piston is extruded from a cylinder main body. It is a figure explaining the flow of air when a piston is returned to a cylinder body. It is a figure explaining the flow of the air at the time of a piston returning to a cylinder body in the state where the 2nd vent hole was flooded.

  Hereinafter, based on an accompanying drawing, an air cylinder and an exhaust brake device concerning one embodiment of the present invention are explained. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As shown in FIGS. 1 and 2, the exhaust brake device 10 includes a valve housing 11 interposed in exhaust pipes 2 </ b> A and 2 </ b> B extending in the longitudinal direction of the vehicle body, and a bush 12 (see FIG. 1) on a bearing portion of the valve housing 11. And a shutter valve 13 (see FIG. 1) pivotally supported, an air cylinder 20 operated by compressed air supplied from an air tank (not shown), a shaft 13A of the shutter valve 13 (see FIG. 1), and an air cylinder A link mechanism 14 that connects the rods 23 of the 20, a bracket 15 that is formed in a substantially U shape that opens laterally, and in which the air cylinder 20 is attached to the vertical plate portion, and a substantially housing that opens on one side. It is formed in a body shape, and its opening edge is brought into contact with the peripheral edge of the bracket 15 so that at least a part of the link mechanism 14 and the air cylinder 20 is accommodated therein. An outer cover member (16) for, and a target water preventing cover member 30 which is fitted on the outer periphery of the air cylinder 20.

  In either case, when the exhaust brake switch (not shown) is turned on and the accelerator pedal is released, compressed air is supplied to the air cylinder 20 to push out the rod 23, and the shutter valve 13 is rotated via the link mechanism 14. The exhaust brake is actuated by being moved and closing the exhaust passage.

  Next, a detailed configuration of the air cylinder 20 of the present embodiment will be described based on FIGS.

  The air cylinder 20 has a hollow cylindrical cylinder body 21, a piston 22 slidably accommodated in the cylinder body 21, one end fixed to the piston 22 and the other end projecting from the cylinder body 21. The normal pressure chamber (first hollow chamber) 24 defined on the rod 23 side in the cylinder main body 21 with the rod 23 therebetween and the normal pressure chamber 24 in the cylinder main body 21 opposite to the piston 22 is opposite to each other. A working pressure chamber (second hollow chamber) 25 partitioned on the side (piston head side), a return spring 26 housed in the normal pressure chamber 24 and biasing the piston 22 toward the working pressure chamber 25 side, A water-preventing cover member 30 having a diameter larger than that of the cylinder body 21 is provided.

  The cylinder main body 21 is fixed to the bracket 15 with bolts in a state where its axis is directed in the longitudinal direction of the vehicle body. A first vent hole 27 that allows air to flow into or out of the normal pressure chamber 24 is formed through the upper wall portion of the cylinder body 21 on the normal pressure chamber 24 side. An air tank (not shown) is connected to the working pressure chamber 25 via a supply pipe 19. When compressed air is supplied to the working pressure chamber 25, the piston 22 moves against the biasing force of the return spring 26 to the normal pressure chamber 24 side (forward) to push out the rod 23, while When the supply of compressed air is stopped, the piston 22 is pushed back to the working pressure chamber 25 side (rear side) by the urging force of the return spring 26 together with the rod 23.

  The waterproof cover member 30 has a substantially cylindrical shape having flanges at both opening edges so as to cover the outer peripheral surface of the cylinder body 21 in which the first vent holes 27 are formed in the circumferential direction. More specifically, the waterproof cover member 30 includes a cylindrical wall portion 31 that is spaced apart from the outer peripheral surface of the cylinder body 21 and faces the outer peripheral surface of the cylinder main body 21. An annular first flange portion 32 closely contacting the surface, and an annular second flange portion 33 protruding radially inward from the rear peripheral edge of the cylindrical wall portion 31 and closely contacting the outer peripheral surface of the cylinder body 21. ing. That is, on the outer periphery of the cylinder body 21, an annular air flow path F that is partitioned by the cylindrical wall portion 31, the first flange portion 32, and the second flange portion 33 and communicates with the first vent hole 27 is formed. .

  In the present embodiment, a second vent hole 34 that allows the air flow path F to communicate with the outside is formed through the lower wall portion of the cylindrical wall portion 31. In addition, a third vent hole 35 that allows the air flow path F to communicate with the outside is formed in the lateral side wall portion where the cylindrical wall portion 31 protrudes most in the lateral direction as viewed in the axial direction of the moisture prevention cover member 30 (as viewed from the front of the vehicle body). It is formed through. In the illustrated example, the third vent hole 35 is provided in the right side wall portion close to the outer cover member 16, but may be provided in the left side wall portion close to the opposite bracket 15. Good. Moreover, the 3rd ventilation hole 35 may be provided in both the right-and-left horizontal side wall part.

  In the present embodiment, the third vent hole 35 is preferably formed as a long hole extending substantially parallel to the axial direction (the vehicle body longitudinal direction) of the cylinder body 21 (see FIG. 1). In other words, the third vent hole 35 is formed so that the longitudinal direction thereof is the longitudinal direction of the vehicle body while opening in the lateral direction of the vehicle body. In this way, by opening the third ventilation hole 35 sideways, water that is scraped up and scattered by a tire (not shown) or water that passes through the outer cover member 16 and falls from above is transferred to the third ventilation hole 35. The direct contact is eliminated and water can be effectively prevented from entering the air flow path F from the third vent hole 35. Further, since the third ventilation hole 35 is a long hole extending in the longitudinal direction of the vehicle body, the opening area of the third ventilation hole 35 can be effectively ensured while preventing water from entering.

  Next, the operation of the exhaust brake device 10 according to the present embodiment will be described.

  When the compressed air is supplied to the working pressure chamber 25 by turning on the exhaust brake and the pressure in the working pressure chamber 25 rises, the piston 22 is integrated with the rod 23 against the urging force of the return spring 26 to the normal pressure chamber 24 side. Accordingly, the air in the normal pressure chamber 24 is discharged from the first vent hole 27 to the outside through the air flow path F through the second vent hole 34 and the third vent hole 35 (see FIG. 5). ). That is, when the piston 22 is pushed out, the second vent hole 34 and the third vent hole 35 function as air discharge holes.

  On the other hand, when the supply of compressed air to the working pressure chamber 25 is stopped and the pressure is reduced by turning off the exhaust brake, the piston 22 is pushed back to the working pressure chamber 25 side by the urging force of the return spring 26 together with the rod 23. At this time, since the outside air flowing into the air flow path F from the second vent hole 34 and the third vent hole 35 flows into the normal pressure chamber 24 through the first vent hole 27, the negative pressure in the normal pressure chamber 24 is reduced. Pressure generation is prevented (see FIG. 6). That is, when the piston 22 is returned, the second vent hole 34 and the third vent hole 35 function as air suction holes.

  By the way, when water that has entered from the gap between the bracket 15 and the outer cover member 16 accumulates around the lower portion of the water-proof cover member 30 and the second vent hole 34 is submerged, the second vent hole 34 is blocked by water. Therefore, the air suction hole cannot function. If the exhaust brake is turned off and the piston 22 is returned in such a state, in the structure having no air suction hole in addition to the second ventilation hole 34, a negative pressure is generated in the atmospheric pressure chamber 24, and the second passage There is a possibility that water is sucked up from the pores 34.

  In the present embodiment, since the third vent hole 35 is provided at a position higher than the second vent hole 34 of the water-preventing cover member 30, the second vent hole 34 is submerged as shown in FIG. However, the outside air flows into the air flow path F from the third vent hole 35 and flows into the normal pressure chamber 24 through the first vent hole 27. That is, even when the second vent hole 34 is submerged, the third vent hole 35 reliably functions as an air suction hole, thereby preventing the generation of negative pressure in the normal pressure chamber 24, thereby the second vent hole. The suction of water from 34 is effectively prevented.

  As described in detail above, in the present embodiment, the third ventilation hole 35 is provided at a position higher than the second ventilation hole 34 of the cylindrical wall portion 31, so that even when the second ventilation hole 34 is submerged, The third vent hole 35 functions as an air suction hole. Thereby, even if the piston 22 is returned in a state where the second ventilation hole 34 is submerged, the outside air flows into the air flow path F from the third ventilation hole 35, and the atmospheric pressure chamber 24 through the first ventilation hole 27. By flowing in, it becomes possible to effectively prevent the generation of negative pressure in the normal pressure chamber 24, and the suction of water from the second vent hole 34 can also be reliably prevented.

  Further, in the present embodiment, the third ventilation hole 35 is formed as a long hole extending in the axial direction of the cylinder body 21 (the vehicle longitudinal direction). That is, the third vent hole 35 is opened in the lateral direction of the vehicle body, and the longitudinal direction thereof is formed to be the longitudinal direction of the vehicle body, so that water that is scooped up and scattered by the tire or water that falls from above is the third. It is possible to prevent direct contact with the vent hole 35 and reliably prevent water from entering the cylinder body 21 from the third vent hole 35 through the air flow path F.

  In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably and can implement.

  For example, the third vent hole 35 is not limited to a long hole, and may be a circular or rectangular hole. Further, the position where the third vent hole 35 is provided is not limited to the lateral wall portion that protrudes most in the lateral direction of the cylindrical wall portion 31, and if it is a position that is higher than the flood level above the second vent hole 34, It can also be provided in other portions of the cylindrical wall portion 31.

  Moreover, in the said embodiment, although the air cylinder 20 is arrange | positioned so that the rod protrusion side may face the vehicle body front, you may arrange | position in the reverse direction. Further, the exhaust brake device 10 is provided in a portion where the exhaust pipes 2A and 2B extend in the longitudinal direction of the vehicle body, but the exhaust pipes 2A and B are provided in other portions such as a portion extending in the vehicle body width direction and a bent portion. It may be provided.

  The use of the air cylinder 20 is not limited to the exhaust brake device 10, and can be widely applied to other valve opening / closing devices such as an intake throttle valve, an exhaust throttle valve, and an EGR valve.

2A, B Exhaust pipe 10 Exhaust brake device 11 Valve housing 13 Shutter valve 14 Link mechanism 15 Bracket 16 Outer cover member 20 Air cylinder 21 Cylinder body 22 Piston 23 Rod 24 Normal pressure chamber 25 Operating pressure chamber 26 Return spring 27 First vent hole 30 Water-resistant cover member 31 Cylindrical wall portion 32 First flange portion 33 Second flange portion 34 Second vent hole 35 Third vent hole

Claims (6)

A hollow cylindrical cylinder body, a piston slidably accommodated in the cylinder body, a rod having one end fixed to the piston and the other end protruding from the cylinder body, and the piston separated A first hollow chamber defined on the rod side in the cylinder body, and a second hollow defined on the opposite side to the first hollow chamber in the cylinder body across the piston and supplied with operating pressure. A chamber, a spring housed in the first hollow chamber and biasing the piston toward the second hollow chamber, and a first passage formed through the outer wall of the cylinder body on the first hollow chamber side. The cylinder body has a pore and a diameter larger than that of the cylinder main body, and a peripheral edge is brought into contact with the outer surface of the cylinder main body so that the first wall is interposed between the outer surface of the cylinder main body and the inner surface of the cylindrical wall portion. 1 communication with vent A cover member that forms an air flow path, a second vent hole that is formed through the lower wall portion of the cylindrical wall portion to communicate the air flow channel with the outside, and the lower wall portion of the cylindrical wall portion, An air cylinder, comprising: a third vent hole that is formed through another different part to communicate the air flow path with the outside. The air cylinder according to claim 1, wherein the third ventilation hole is formed as a long hole extending in an axial direction of the cylinder body. The cover member is formed in a cylindrical shape, and the third ventilation hole is provided on a lateral side wall portion where the cylindrical wall portion protrudes most in the lateral direction when viewed in the axial direction of the cover member. The described air cylinder. An exhaust brake device comprising the air cylinder according to any one of claims 1 to 3,
A valve housing interposed in an exhaust pipe, a shutter valve pivotally supported by the valve housing and capable of closing an exhaust passage, a link mechanism connecting the shutter valve and the rod, and the cylinder An exhaust brake device comprising: a bracket to which the main body is attached. 5. The exhaust brake device according to claim 4, wherein the exhaust pipe extends in the vehicle body front-rear direction, and the cylinder body is attached to the bracket with its axial center direction directed toward the vehicle body front-rear direction. And further comprising an outer cover member that is formed in a housing shape with one side open, and that has an opening edge in contact with the bracket and accommodates at least a part of the link mechanism and the cylinder body therein. Item 6. The exhaust brake device according to Item 4 or 5.

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