JP2016050624A - Spring brake chamber and seal ring for spring brake chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal ring capable of forcedly fixing a seal member against the first piston and provide a spring brake chamber.SOLUTION: A spring brake chamber comprises: a first case 4 constituting a primary side chamber 2; a first piston 21 forming a cylindrical shape, having a flange part 21a protruding in a radial outward direction and moving in the first case 4; a guide member 26 fixed to the first piston 21, and coming in slide contact with the inner circumferential surface of the first case 4 as the first piston 21 is moved; and a resilient seal member 27 held between the guide member 26 and the first piston 21 and fixed there.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a spring brake chamber and a seal ring of a spring brake chamber.

  Spring braking chambers controlled by air pressure are employed in braking devices for vehicles such as buses, trucks, and trailers. The spring brake chamber includes a primary chamber having a first piston and a secondary chamber having a second piston. In this spring brake chamber, for example, a wedge provided at the tip of the second piston protrudes toward the brake drum, and the brake shoe of the brake drum is expanded to operate the brake.

  The secondary chamber is provided with a diaphragm for moving the second piston forward and backward with respect to the brake drum. This diaphragm partitions the space in the secondary chamber into a second control chamber and a piston chamber.

  The primary chamber includes a first push rod that forcibly displaces the above-described diaphragm to the opposite side of the primary chamber. The first push rod is provided so as to be able to advance and retreat with respect to the secondary side chamber according to the operation of the first piston sliding in the case of the primary side chamber. The space inside the primary side chamber is partitioned by the first piston into a spring chamber and a first control chamber provided near the secondary side chamber. The spring chamber is provided with a compression spring that biases the first piston toward the secondary chamber.

  In the spring brake chamber configured in this way, the wedge provided on the second piston is driven by displacing the first piston and the diaphragm by controlling the pressure in the first control chamber and the second control chamber, Control the amount of braking.

  In addition, a seal ring (piston cup) is provided between the case of the primary chamber and the first piston in order to improve the airtightness of the first control chamber (see, for example, Patent Document 1). The seal ring includes an engaging portion formed in a concave shape. The seal ring is fixed to the first piston by fitting the engaging portion to a convex portion provided on the first piston. Moreover, this seal ring reduces sliding resistance by providing the 1st top part and 2nd top part which contact with respect to a case.

JP 2012-87870 A

  In the above-described seal ring, the sliding resistance with the case can be reduced and the sliding property of the first piston can be increased. However, the force for fixing the elastic seal member to the first piston side still has room for improvement. There is.

  This invention is made | formed in view of such a situation, The objective is to provide the spring brake chamber which can fix a sealing member to a 1st piston firmly, and its seal ring.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A spring brake chamber that solves the above problems includes a first case that constitutes a primary side chamber, a first piston that has a cylindrical shape and has a flange portion that protrudes radially outward, and moves in the first case. A guide member fixed to the first piston and slidably contacting the inner peripheral surface of the first case as the first piston moves, and having elasticity and being sandwiched between the guide member and the first piston And a sealing member fixed.

  The seal ring of the spring brake chamber that solves the above-described problem is sandwiched between the guide member and the first piston while having elasticity with a guide member fixed to the first piston moving in the primary side chamber. And a sealing member to be fixed.

  According to the above configuration, the seal member can be fixed to the first piston by being sandwiched between the guide member and the first piston. For this reason, a sealing member can be firmly fixed to the 1st piston compared with the sealing member provided with the structure directly engaged with the 1st piston.

  In the spring brake chamber, it is preferable that the first piston includes a closed end portion and an open end portion provided with the flange portion, and the guide member has a groove portion fitted to the flange portion.

  According to the above configuration, since the groove portion of the guide member is fitted to the flange portion provided at the opening end portion of the first piston, the convex portion for fitting the guide member to the outer peripheral surface of the first piston, The recess may not be provided. For this reason, restrictions on manufacturing the first piston can be reduced.

  With respect to the spring brake chamber, the seal member extends along the radial direction of the first piston by one end portion that is in sliding contact with the inner peripheral surface of the first case, the outer peripheral surface of the first piston, and the guide member. It is preferable to have the other edge part pinched | interposed from both sides.

  According to the said structure, since the other edge part of a sealing member is pinched | interposed by a 1st piston and a guide member, it does not contact with the internal peripheral surface of a 1st case. For this reason, the contact area of a sealing member and the internal peripheral surface of a 1st case can be reduced.

In the spring brake chamber, it is preferable that the other end portion of the seal member abuts on a flange portion provided at an opening end of the first piston.
According to the above configuration, the seal member is sandwiched between the first piston and the guide member, and the other end abuts against the flange portion of the first piston. When sliding inside, the axial displacement of the seal member is suppressed.

  With respect to the spring brake chamber, the first piston includes a closed end portion and an open end portion provided with the flange portion, and the guide member is fitted with a fitted portion provided in the first piston. The seal member has one end that is in sliding contact with the inner peripheral surface of the first case, and the axial direction of the first piston is formed by the flange portion and the guide member. It is preferable to be sandwiched from both sides.

  According to the said structure, a sealing member is pinched | interposed from the both sides of the axial direction of a 1st piston by a flange part and a guide member. For this reason, the seal member can be firmly fixed to the first piston while reducing restrictions such as the shape and thickness of the seal member.

About this spring brake chamber, it is preferable that the said sealing member and the said guide member have a fitting structure fitted to each other.
According to the above configuration, the force with which the seal member and the guide member are coupled to each other can be increased.

  According to the spring brake chamber and the seal ring of the present invention, the seal member can be firmly fixed to the first piston.

A sectional view of a spring brake chamber at the time of parking brake operation of one embodiment. The enlarged view of the primary side chamber of a spring brake chamber. Sectional drawing of the spring brake chamber at the time of brake cancellation | release. Sectional drawing of the spring brake chamber at the time of foot brake action | operation. The enlarged view of the primary side chamber of a modification. The enlarged view of the primary side chamber of a modification. The enlarged view of the primary side chamber of a modification. The enlarged view of the seal structure of a modification.

Hereinafter, an embodiment of the spring brake chamber will be described with reference to FIGS.
As shown in FIG. 1, the spring brake chamber 1 includes a cylindrical primary chamber 2 (piggyback) and a cylindrical secondary chamber 3 (service chamber) connected to the primary chamber 2. ing. Both ends of the primary chamber 2 are closed. One end of the secondary chamber 3 is open and the other end is closed. A cylindrical rod insertion portion 7 through which the second push rod 33 is inserted is provided at one end of the secondary chamber 3, that is, the end of the secondary chamber 3 opposite to the end near the primary chamber 2. It has been.

  The spring brake chamber 1 includes a cylindrical first case 4 constituting the primary chamber 2, a cylindrical second case 5 constituting the secondary chamber 3, and a connection case 6. The connection case 6 constitutes the primary chamber 2 in cooperation with the first case 4 and constitutes the secondary chamber 3 in cooperation with the second case 5. The first case 4 has an open end, a closed end located on the opposite side of the open end, and an open end 4a located near the open end. The second case 5 has open ends at both ends. The connection case 6 has an I-shaped cross section, and has an open end near the first case 4 and an open end located near the open end. The connection case 6 constitutes the primary side chamber 2 by closing the first case 4 and constitutes the secondary side chamber 3 by closing the second case 5. The second case 5 includes a large diameter portion 5 a that constitutes the secondary chamber 3 and a small diameter portion 5 b that constitutes the rod insertion portion 7.

  On the outer surface of the opening end of the connection case 6, a recess 6 a for installing an O-ring 8 having an O-shaped cross section as a seal member is formed. The concave portion 6 a is a holding portion formed by the two ridge portions 6 b and 6 c and is formed over the entire outer surface of the connection case 6. The first case 4 and the connection case 6 are connected by caulking the opening end 4a of the first case 4 in a state where one end of the connection case 6 is in contact with the opening end 4a of the first case 4. Has been.

  A rib 5 c is formed at the end of the second case 5 near the connecting case 6, and a rib 6 d is formed at the end of the connecting case 6 near the second case 5. The rib 5c of the second case 5 and the rib 6d of the connecting case 6 are fastened and fixed by a clamp ring 9.

  The connection case 6 is formed with a primary inflow / outflow hole 11 through which compressed air enters and exits the primary side chamber 2. The primary side inflow / outflow hole 11 is connected to a primary side outflow / inflow valve (not shown) for controlling the supply and discharge of compressed air. By this primary side inflow / outflow valve, compressed air is supplied to the primary side chamber 2 through the primary side outflow / inflow hole 11, and air in the primary side chamber 2 is discharged through the primary side outflow / inflow hole 11. .

  In addition, the connection case 6 is formed with a secondary inflow / outflow hole 12 through which compressed air enters and exits the secondary side chamber 3. The secondary-side inflow / outflow hole 12 is connected to a secondary-side inflow / outflow valve (not shown) that controls the supply and discharge of compressed air. By this secondary side inflow / outflow valve, compressed air is supplied to the secondary side chamber 3 through the secondary side outflow / inflow hole 12, and air in the secondary side chamber 3 passes through the secondary side outflow / inflow hole 12. Is discharged through.

  A cylindrical first piston 21 is accommodated in the primary chamber 2 so as to be movable in the axial direction of the primary chamber 2. The first piston 21 is manufactured by processing a sheet metal and has an open end and a closed end. A flange portion 21 a that protrudes radially outward is provided at the opening end of the first piston 21. The primary chamber 2 is partitioned by a first piston 21 into two chambers, a spring chamber 15 in which a compression spring 23 is accommodated and a first control chamber 13. The compression spring 23 biases the first piston 21 toward the secondary chamber 3 side.

  A cylindrical first push rod 22 that can advance and retreat in the axial direction integrally with the first piston 21 is fixed to the first piston 21. The first push rod 22 is inserted into the communication hole 41 of the connection case 6. The inside of the first push rod 22 is a cavity. A circulation mechanism 50 that circulates the air in the spring chamber 15 to the second control chamber 14 in the secondary side chamber 3 is provided inside the first push rod 22. The compression spring 23 installed in the primary side chamber 2 biases the first piston 21 toward the secondary side chamber 3.

  A diaphragm 31 is installed in the secondary chamber 3. The diaphragm 31 divides the inside of the secondary side chamber 3 into two chambers of the second control chamber 14 and the piston chamber 16 in which the second piston 32 is disposed. The entire periphery of the edge of the diaphragm 31 is fixed to the inner wall of the secondary chamber 3 by being sandwiched between the rib 5 c of the second case 5 and the rib 6 d of the connection case 6. The diaphragm 31 is a film made of an elastic material, and is displaced in the secondary side chamber 3 by the compressed air supplied to the second control chamber 14.

  In the secondary chamber 3, a second piston 32 that moves the rod insertion part 7 integrally with the movement of the diaphragm 31 is disposed. The second piston 32 includes a disc part 32 a attached to the diaphragm 31 and a rod-like part 32 b that moves through the rod insertion part 7. A cylindrical slot portion is formed at the end of the rod-like portion 32b. A rod-shaped second push rod 33 is inserted into the slot. A cylindrical rod guide 34 is attached to the tip of the second piston 32. The rod guide 34 slides on the inner peripheral surface of the rod insertion portion 7 and guides the second piston 32. A cylindrical dust cover 35 is attached inside the rod insertion portion 7.

  As shown by a broken line in FIG. 1, a wedge 10 for expanding the brake shoe of the brake drum is connected to the end of the tip of the second push rod 33. When the wedge 10 enters the brake drum, the brake shoe is expanded to operate the brake, and when the wedge 10 retracts from the brake drum, the brake shoe returns to a predetermined position and the brake is released.

  A resin first guide member 45 and a sealing member 49 are mounted on the inner peripheral surface of the communication hole 41 of the connection case 6 in order from the primary chamber side. The first guide member 45 guides the sliding of the first push rod 22. The sealing member 49 seals the gap between the communication hole 41 and the first push rod 22. Further, the sealing member 49 has an opening with a C-shaped cross section that opens toward the secondary chamber 3, and from the second control chamber 14 of the secondary chamber 3 to the first control chamber 13 of the primary chamber 2. Block the air flow.

  An annular seal ring 25 is provided on the outer peripheral surface of the first piston 21. The seal ring 25 seals the first control chamber 13. The seal ring 25 includes a resin guide member 26 and a seal member 27 made of an elastic material. The guide member 26 has an annular shape. Further, as the first piston 21 moves, the guide member 26 slides on the inner peripheral surface of the first case 4 on the outer peripheral surface to guide the sliding of the first piston 21. The seal member 27 is made of rubber, blocks air flow from the first control chamber 13 toward the spring chamber 15, and allows air flow from the spring chamber 15 toward the first control chamber 13.

The configuration of the seal ring 25 will be further described with reference to FIG.
The guide member 26 has an L-shaped cross section and is harder and more rigid than the seal member 27. An annular groove 26 c is formed on the inner peripheral surface of the guide member 26 over the entire circumference. The guide member 26 is fixed to the first piston 21 by fitting the groove portion 26c with the flange portion 21a of the first piston 21. Further, of the inner peripheral surface of the guide member 26, an end portion 26b opposite to the end portion 26a where the groove portion 26c is formed protrudes radially inward. In a state where the guide member 26 is fixed to the flange portion 21a, a gap is provided between the inner peripheral surface of the guide member 26 and the outer peripheral surface of the first piston 21.

  The seal member 27 includes a lip portion 27b at one end portion. The lip portion 27b has a shape in which the cross-section is bifurcated by forming a concave portion 27d at the end thereof. An outer lip portion 27e is provided on the radially outer side of the seal member 27, and an inner lip portion 27f is provided on the radially inner side.

  The fixed end 27a, which is the other end of the seal member 27, is sandwiched by a gap provided between the outer peripheral surface of the first piston 21 and the inner peripheral surface of the guide member 26, and the flange of the first piston 21. It is in contact with the portion 21a. That is, the fixed end portion 27 a is fixed by being sandwiched between the outer peripheral surface of the first piston 21 and the guide member 26 from both radial sides of the seal member 27. Accordingly, the fixed end portion 27 a does not contact the inner peripheral surface of the first case 4.

  Further, the seal member 27 is provided with a groove portion 27c. The groove portion 27c and the end portion 26b of the guide member 26 constitute a fitting structure for connecting the guide member 26 and the seal member 27 to each other. With this fitting structure, the guide member 26 and the seal member 27 are connected to each other.

  Further, in the outer peripheral surface of the seal member 27, an inclined surface 27g is provided in a region extending from the groove portion 27c to the lip portion 27b so as to project outward in the radial direction toward the lip portion 27b.

  As shown by the solid line in FIG. 2, when the first piston 21 to which the seal ring 25 is attached is accommodated in the first case 4, the lip portion 27 b is elastically deformed, and the outer lip portion 27 e is the first case 4. The inner lip portion 27f comes into contact with the outer peripheral surface of the first piston 21. As a result, in the lip portion 27b, the outer lip portion 27e and the inner lip portion 27f as shown by the solid line in FIG. Further, the outer peripheral surface of the guide member 26 contacts the inner peripheral surface of the first case 4.

  When the pressure in the spring chamber 15 is higher than that in the first control chamber 13, the seal member 27 is elastically deformed in a direction in which the outer lip portion 27 e and the inner lip portion 27 f are brought closer to each other to allow air flow. Further, when the pressure in the first control chamber 13 is higher than that in the spring chamber 15, the lip portion 27 b expands in the direction in which the concave portion 27 d is expanded, preventing the flow of air from the first control chamber 13 toward the spring chamber 15. To do.

  Further, a gap 28 is provided between the inclined surface 27 g of the seal member 27 and the inner peripheral surface of the first case 4. The grease applied to the inner peripheral surface of the first case 4 is stored in the gap 28. When the first piston 21 slides in the first case 4, the grease accumulated in the gap 28 is applied again to the inner peripheral surface of the first case 4.

Next, the operation of the spring brake chamber 1 configured as described above will be described.
First, an operation when the parking brake is operated will be described with reference to FIG. When the operation of the parking brake is performed, the primary side inflow / outflow valve connected to the primary side outflow / inflow hole 11 is opened, and the compressed air is discharged from the first control chamber 13. Moreover, the secondary side outflow / inflow valve connected to the secondary side outflow / inflow hole 12 is opened, and the second control chamber 14 is opened to the atmosphere.

  In the primary side chamber 2, the first piston 21 moves toward the secondary side chamber 3 by the urging force of the compression spring 23 and is fixed at the parking brake operating position. The first push rod 22 fixed to the first piston 21 protrudes into the secondary chamber 3 and forcibly presses the diaphragm 31 toward the rod insertion portion 7. Thereby, the 2nd piston 32 is hold | maintained in the state which moved toward the rod insertion part 7, and the wedge 10 is hold | maintained in the brake lock position which expands a brake shoe.

  Next, the operation when the parking brake is released will be described with reference to FIG. The operation when the foot brake is released is the same. When the operation of the parking brake or the foot brake is released, the primary side outflow / inflow valve connected to the primary side outflow / inflow hole 11 is opened, and the compressed air is supplied to the first control chamber 13. Further, the secondary side inflow / outflow valve connected to the secondary side outflow / inflow hole 12 is opened, and the compressed air is discharged from the second control chamber 14.

  In the primary chamber 2, the first piston 21 moves toward the opposite side of the secondary chamber 3 against the urging force of the compression spring 23 by the compressed air in the first control chamber 13, and the parking brake is not activated. Placed in position. Further, the first push rod 22 fixed to the first piston 21 is withdrawn from the secondary chamber 3. In the secondary chamber 3, the compressed air is discharged from the second control chamber 14, whereby the diaphragm 31 is displaced toward the primary chamber 2. Thereby, the 2nd piston 32 moves to the primary side chamber 2 side, and the wedge 10 retreats from the brake lock position which expands a brake shoe.

  Next, the operation when the foot brake is operated will be described with reference to FIG. When the foot brake is operated, the primary side inflow / outflow valve connected to the primary side outflow / inflow hole 11 is opened, and the compressed air is supplied to the first control chamber 13. Further, the secondary side inflow / outflow valve connected to the secondary side outflow / inflow hole 12 is opened, and the compressed air is supplied to the second control chamber 14.

  In the primary chamber 2, the first piston 21 moves toward the opposite side of the secondary chamber 3 against the urging force of the compression spring 23 by the compressed air in the first control chamber 13, and the parking brake is not activated. Placed in position. In the secondary chamber 3, the diaphragm 31 is displaced toward the rod insertion portion 7 by the compressed air in the second control chamber 14. Then, the second piston 32 moves toward the rod insertion portion 7 by the pressing force from the diaphragm 31. Thereby, the 2nd piston 32 is hold | maintained in the state which moved toward the rod insertion part 7, and the wedge 10 is hold | maintained in the brake operation position which expands a brake shoe. The brake operation amount is changed according to the amount of compressed air supplied to the second control chamber 14.

  The first piston 21 slides in the first case 4 while being guided by the guide member 26 of the seal ring 25 as the brake is activated and deactivated. Furthermore, when the first piston 21 slides, only the lip portion 27b of the seal member 27 is in sliding contact with the inner peripheral surface of the first case 4, and therefore, compared with the seal member 27 fitted to the first piston 21, The contact area with the inner peripheral surface of the first case 4 is reduced, and wear of the seal member 27 is suppressed. For this reason, the durability of the seal ring 25 can be improved and the life can be extended. Further, sliding resistance when the first piston 21 moves can also be reduced.

  Further, since the seal member 27 is sandwiched and fixed between the outer peripheral surface of the first piston 21 and the guide member 26 that is more rigid than the seal member 27, the seal member fitted to the first piston 21. Compared to 27, the seal member 27 can be firmly fixed to the first piston 21. Furthermore, the end 26b of the guide member 26 and the groove 27c of the seal member 27 are fitted, whereby the guide member 26 and the seal member 27 are firmly connected. For this reason, dropping of the seal member 27 can be further suppressed as compared with the conventional case.

According to the embodiment, the following effects can be obtained.
(1) The seal member 27 is sandwiched and fixed between the first piston 21 and the guide member 26 fixed to the flange portion 21a. For this reason, the seal member 27 can be firmly fixed to the first piston 21 as compared with a seal member provided with a structure that is fitted and fixed directly to the first piston 21.

  (2) Since the groove portion 26 c of the guide member 26 is fitted to the flange portion 21 a provided at the opening end portion of the first piston 21, the guide member 26 is fitted to the outer peripheral surface of the first piston 21. There is no need to provide convex portions or concave portions. Therefore, since restrictions on manufacturing the first piston 21 can be reduced, for example, the first piston 21 can be formed from a sheet metal.

  (3) The seal member 27 is sandwiched between the first piston 21 and the guide member 26 from both radial sides of the first piston 21. Accordingly, at least the fixed end portion 27 a of the seal member 27 does not come into contact with the inner peripheral surface of the first case 4. Accordingly, the contact area between the seal member 27 and the inner peripheral surface of the first case 4 is reduced, so that durability can be enhanced.

  (4) The seal member 27 is sandwiched between the first piston 21 and the guide member 26, and the fixed end portion 27 a comes into contact with the flange portion 21 a of the first piston 21. For this reason, when the first piston 21 slides in the first case 4, the axial displacement of the seal member 27 is suppressed.

  (5) Since the groove portion 27c of the seal member 27 and the end portion 26b of the guide member 26 are fitted to each other, the force with which the seal member 27 and the guide member 26 are coupled to each other can be increased. Therefore, the dropout of the seal member 27 is further suppressed.

(Other embodiments)
In addition, each said embodiment can also be implemented with the following forms.
As shown in FIG. 5, the seal ring 25 may be configured such that the seal member 27 is sandwiched between the flange portion 21 a of the first piston 21 and the guide member 26 fixed to the outer peripheral surface of the flange portion 21 a. Good. For example, the guide member 26 has an H-shaped cross section, and includes a fitting convex portion 26e as a fitting portion and a lightening portion 26f. In addition, the seal member 27 has a tip portion 27 i that is in sliding contact with the inner peripheral surface of the first case 4, and a recess portion 27 j provided in the tip portion 27 i. The guide member 26 is fitted to a fitting groove 21b as a fitted portion formed on the outer peripheral surface of the first piston 21 with the fitting convex portion 26e. Fixed. The fitting groove 21b is formed by cutting or the like when the first piston 21 is made of sheet metal. According to this configuration, the seal member 27 is sandwiched between the flange portion 21 a and the guide member 26 from both sides along the axial direction of the first piston 21, thereby restricting the thickness and shape of the seal member 27. The seal member 27 can be firmly fixed while reducing the number.

  As shown in FIG. 6, the seal ring 25 includes a seal member 27 sandwiched between a flange portion 21a of the first piston 21 and a guide member 26 fixed to the outer peripheral surface of the flange portion 21a. And the structure which has a connection structure which fixes the sealing member 27 mutually may be sufficient. For example, the guide member 26 includes a fitting convex portion 26e that fits in the fitting groove 21b of the first piston 21, and a connecting portion 26g. A connecting groove 26h is formed in the connecting portion 26g. The seal member 27 includes a sliding contact portion 27l that is in sliding contact with the inner peripheral surface of the first case 4, and a connecting portion 27k having a groove portion 27m. The guide member 26 and the seal member 27 are connected to the connecting groove 26h of the guide member 26 at the tip of the connecting portion 27k of the seal member 27, and connected to the groove 27m of the seal member 27 at the tip of the connecting portion 26g of the guide member 26. Are fixed to each other. According to this configuration, the seal member 27 is firmly fixed by being sandwiched between the flange portion 21a and the guide member 26 from both sides along the axial direction of the first piston 21. The force with which the seal member 27 and the guide member 26 are connected can be increased.

  As shown in FIG. 7, the seal ring 25 includes a seal member 27 sandwiched between a flange portion 21a of the first piston 21 and a guide member 26 fixed to the outer peripheral surface of the flange portion 21a. And the structure which has a connection structure which fixes the sealing member 27 mutually may be sufficient. For example, the guide member 26 includes a fitting convex portion 26e that fits in the fitting groove 21b of the first piston 21, and a connecting groove 26h that has an opening. The connecting groove 26h has a large diameter at the end opposite to the opening. The seal member 27 has a connecting projection 27 n, and the outer peripheral surface thereof is in sliding contact with the inner peripheral surface of the first case 4. The connecting convex part 27n protrudes from the main body of the seal member 27, and the tip part has a large diameter. By inserting the connecting convex portion 27n into the connecting groove 26h of the guide member 26, the guide member 26 and the seal member 27 are fixed to each other. According to this configuration, the seal member 27 is firmly fixed by being sandwiched between the flange portion 21a and the guide member 26 from both sides along the axial direction of the first piston 21. The force with which the seal member 27 and the guide member 26 are connected can be increased.

  As shown in FIG. 8, the seal structure provided on the inner peripheral surface of the communication hole 41 of the connection case 6 includes a first guide member 45, a rubber D-ring 46, and a rubber C-shaped cross section. 1C ring 47 may be comprised. The D ring 46 seals the gap between the communication hole 41 and the first push rod 22. The first C ring 47 has an opening with a C-shaped cross section that opens toward the secondary chamber 3, and air from the second control chamber 14 of the secondary chamber 3 to the first control chamber 13 of the primary chamber 2. Block the flow of

The sealing member 27 may prevent the flow of air from the spring chamber 15 toward the first control chamber 13 by adjusting its elastic modulus.
In the above embodiment, the seal member 27 is applied to the spring brake chamber 1 of the wedge brake system having the connection port made of the wedge 10, but may be applied to chambers of other brake systems. For example, it may be applied to a spring brake chamber of a so-called S cam brake system, or may be applied to a spring brake chamber of a disc brake system.

  DESCRIPTION OF SYMBOLS 1 ... Spring brake chamber, 2 ... Primary side chamber, 3 ... Secondary side chamber, 4 ... 1st case, 4a ... Open end part, 5 ... 2nd case, 5a ... Large diameter part, 5b ... Small diameter part, 5c ... Rib, 6 ... Connection case, 6a ... Recess, 6b ... Projection, 6c ... Projection, 6d ... Rib, 7 ... Rod insertion part, 8 ... O-ring, 9 ... Clamp ring, 10 ... Wedge, 11 ... Primary Side inflow / outlet hole, 12 ... Secondary inflow / outlet hole, 13 ... First control chamber, 14 ... Second control chamber, 15 ... Spring chamber, 16 ... Piston chamber, 21 ... First piston, 21a ... Flange portion, 21b ... fitting groove, 22 ... first push rod, 23 ... compression spring, 25 ... seal ring, 26 ... guide member, 26b ... ridge, 26c ... groove, 26e ... fitting convex part, 26f ... thinning part, 26g ... connecting part, 26h ... connecting groove, 27 ... seal member, 27a ... Fixed end part, 27b ... Lip part, 27c ... Groove part, 27d ... Recessed part, 27e ... Outer lip part, 27f ... Inner lip part, 27g ... Inclined surface, 27i ... Tip part, 27j ... Recessed part, 27k ... Connecting part, 27l ... Sliding contact portion, 27m ... groove portion, 27n ... coupling convex portion, 28 ... gap, 31 ... diaphragm, 32 ... second piston, 32a ... disc portion, 32b ... rod-like portion, 33 ... second push rod, 34 ... rod guide , 35 ... dust cover, 41 ... communication hole, 45 ... first guide member, 46 ... D ring, 47 ... first C ring, 50 ... circulation mechanism.

Claims (7)

A first case constituting a primary chamber;
A first piston that has a cylindrical shape, has a flange portion that protrudes radially outward, and moves in the first case;
A guide member fixed to the first piston and in sliding contact with the inner peripheral surface of the first case as the first piston moves;
A spring brake chamber, comprising: a seal member that has elasticity and is sandwiched and fixed between the guide member and the first piston. The first piston includes a closed end, and an open end provided with the flange.
The spring brake chamber according to claim 1, wherein the guide member has a groove portion that fits into the flange portion. The seal member is sandwiched from one end portion in sliding contact with the inner peripheral surface of the first case, the outer peripheral surface of the first piston and the guide member from both sides along the radial direction of the first piston. The spring brake chamber according to claim 1, further comprising: an end portion. The spring brake chamber according to claim 3, wherein the other end portion of the seal member abuts on a flange portion provided at an opening end of the first piston. The first piston includes a closed end, and an open end provided with the flange.
The guide member has a fitting portion that fits with a fitted portion provided in the first piston,
The seal member has one end that is in sliding contact with the inner peripheral surface of the first case, and is sandwiched from both sides along the axial direction of the first piston by the flange portion and the guide member. The spring brake chamber described in 1. The spring brake chamber according to any one of claims 1 to 5, wherein the seal member and the guide member have a fitting structure that fits to each other. In the seal ring of the spring brake chamber,
A guide member fixed to a first piston moving in the primary chamber;
A seal ring of a spring brake chamber having elasticity and a seal member that is sandwiched and fixed between the guide member and the first piston.

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