JPH06200967A - Brake cylinder with clearance adjusting mechanism - Google Patents

Abstract

PURPOSE:To curtail sliding places, shorten a sliding time, and reduce drive loss of a piston. CONSTITUTION:A pressing body 12 movable in the direction of the axis and rotationally unmovable around the axis, and a feed body 13 unmovable in the direction of the axis and rotationlly movable around the axis are arranged on the outer circumferential side of a sheath bar 7, the tubular body 6 of a piston 5, the sheath bar 7, the pressing body 12, and the feed body 13 are respectively provided with a first - a fourth ratchet teeth 21, 22, 23, 24, and the second and third ratchet teeth 22, 23 are pressed against the fourth ratchet teeth 24 by means of spring members 10, 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake cylinder with a clearance adjusting mechanism, and more particularly, to a space between a brake shoe and a wheel working surface in a brake slack state automatically linked to the movement of a fluid pressure responsive piston. The present invention relates to a brake cylinder adapted to adjust the clearance.

[0002]

2. Description of the Related Art As is well known, in brake cylinders for railway vehicles and the like, the brake shoe wears due to the frequent braking action, and the brake shoe and the wheel action surface in the brake slack state accordingly. Since the clearance between them gradually increases and the stroke of the piston becomes too large, in order to avoid this, the brake cylinder is equipped with a clearance adjustment mechanism that automatically keeps the clearance within a predetermined error range. To be

A conventional structure of a brake cylinder with a clearance adjusting mechanism of this type is known from, for example, Japanese Utility Model Publication No. 62-8444.

The basic structure disclosed in the publication is, as shown in FIG. 8, a cylinder body 53 having a pressure fluid supply / discharge hole 52,
An air pressure responsive piston 55 fitted in the inner peripheral side of the cylinder body 53 and urged by a return spring 54 in the brake slackening direction (reverse movement direction), and the rear end of the piston 55 rotates about the axis. A linear key groove 56 movably attached and extending in the axial direction and a spiral key groove having a helix angle with respect to the axial direction.
A cylindrical sheath rod 58 with 57 formed on the outer peripheral surface, and this sheath rod
Push rod support 59 screwed to the inner circumference of 58 so as to be rotatable about its axis.
And a push rod 61 having a rear end attached to the push rod receiver 59 and a brake shoe (not shown) coupled to the front end.

A first ratchet gear 63, which is held immovably in the axial direction and rotatable about the axial center, is disposed on the outer peripheral side of the sheath rod 58. The first ratchet gear 63 A first key 62 that engages with the linear key groove 56 of the sheath rod 58 is provided on the inner peripheral surface of the first ratchet gear 63, and a first pressing spring 64 is provided on the outer side of the first ratchet gear 63. A first pawl 65 is provided which contacts the tooth surface of the first ratchet gear 63 by the biasing force and limits the reversal thereof. Further, a second ratchet gear 67, which is held immovably in the axial direction and rotatable about the axial center, is disposed on the outer peripheral side of the sheath rod 58, and the inner periphery of the second ratchet gear 67 is arranged. A second key 66 that engages with the spiral key groove 57 of the sheath rod 58 is provided on the surface so as to project, and on the outer side of the second ratchet gear 67,
A second pawl 69 is provided which abuts against the tooth surface of the second ratchet gear 67 by the biasing force of the second presser spring 68 and limits the reversal thereof.

According to the above construction, from the brake slackened state shown in the same figure, the pressure fluid is supplied and exhausted by the pressure fluid for the braking action.
When the piston 55 is supplied to the inside of the cylinder body 63 from 62, the piston 55 moves in a protruding manner with respect to the cylinder body 63 together with the sheath rod 58, the push rod receiver 59 and the push rod 61, and is connected to the tip of the push rod 61. The wheel is pressed against the wheel working surface to provide a braking effect. During this protruding movement, the second ratchet gear 67 engaged with the spiral key groove 57 of the sheath rod 58 rotates in the forward direction, and during this forward rotation, the sheath rod 58 receives its reaction force and tries to rotate in the reverse direction.
Since the first pawl 65 is in contact with the tooth surface of the first ratchet gear 63 engaged with the linear key groove 56 of the sheath rod 58 by the urging force of the first pressing spring 64, Reversal is blocked.

In this case, when the stroke of the piston 55 is within the reference stroke, the second ratchet gear
Since 67 does not rotate forward beyond the specified angle, the second pawl 69 that is in contact with the tooth surface of this second ratchet gear 67 cannot ride over one tooth of this gear 67, and therefore when the brake is loosened. When the sheath rod 58 moves backward together with the piston 55, the second ratchet gear 67 reverses along the spiral key groove 57 and returns to its original position.

On the other hand, when the stroke of the piston 55 is equal to or greater than the reference stroke, the second ratchet gear 67 normally rotates beyond the specified angle, so that the second pawl 69 is set to 1
It will get over the tooth and mesh with the next tooth, so if the sheath rod 58 moves backward when the brake is loosened,
The second ratchet gear 67 is prevented from reversing due to the meshing between the next tooth and the second pawl 69, so that the sheath rod 58 moves along its own spiral key groove 57 for one tooth of the second ratchet gear 67. Forward only by angle. At this time, the first ratchet gear
63 also rotates forward at the same time.

By the rotation of the sheath rod 58 in this manner, the push rod receiver 59 screwed on the sheath rod 58 and thus the push rod 61.
However, it will project in the axial direction relative to the sheath rod 58 and then the piston 55, and therefore, each time the stroke of the piston 55 exceeds the reference stroke due to wear of the brake shoe, one tooth of the second ratchet gear 67 The push rod 61 projects relative to the piston 55 by a dimension corresponding to the angle of minutes, and the gap between the brake shoe and the wheel working surface is automatically adjusted.

[0010]

However, according to the above-mentioned conventional brake cylinder with a clearance adjusting mechanism, the sheath bar is used.
The second ratchet gear along the spiral keyway 57 formed in 58
Since the second key 66 of 67 moves while sliding, the sliding resistance is large, and the sliding time is long because both of them are always sliding while the piston 55 is moving. Therefore, there is a problem that the driving loss increases due to the sliding of the piston 55 when the piston 55 moves, and that the above-mentioned wear between the two is premature.

If the sheath rod 58 is to be rotated by a predetermined angle in response to a slight change in the stroke of the piston 55, the twist angle of the spiral key groove 57 with respect to the axial direction must be increased. This leads to an increase in sliding resistance and drive loss.

The present invention has been made in view of the above circumstances, and provides a brake cylinder with a clearance adjusting mechanism that can reduce sliding resistance and sliding time, and can be used when a piston moves. The technical issue is to significantly reduce the drive loss in the.

[0013]

The present invention is characterized in that it has the following structure in order to achieve the above technical objects. That is, a push rod having a connecting portion for a brake shoe at its tip, a sheath rod screwed on the outer peripheral side of the push rod so as to be rotatable around an axis, and the sheath rod and the push rod housed in the cylinder body and the cylinder rod. With respect to the axial direction of the fluid pressure responsive piston, and the movement of the piston causes the sheath rod to rotate relative to the push rod relative to the axial center of the piston. In a brake cylinder having a clearance adjusting mechanism that changes a relative position with respect to the axial direction, a tubular body is provided so as to project on the projecting movement side of the piston, and the sheath rod and the sheath rod outer cylinder are axially provided on the inner peripheral side of the tubular body. The sheath rod outer cylinder is biased toward the backward movement side by the main spring member while being fitted so as to be rotatable about the center and relatively movable in the axial direction by a predetermined dimension, and at the outer peripheral side of the sheath rod outer cylinder. To be movable in the axial direction A pressing body that is held so as not to be rotatable about its axis and biased toward the backward movement side by an auxiliary spring member; and a feeding body that is held so as to be rotatable about its axis and immovable in its axial direction. And a first ratchet tooth is formed at the protruding end of the tubular body, and the first ratchet tooth meshes with the outer circumference of the sheath rod outer cylinder when the piston moves by a predetermined dimension. A second ratchet tooth is formed, a third ratchet tooth is formed at the retreat side end of the pressing body, and a fourth ratchet tooth that meshes with the second ratchet tooth and the third ratchet tooth at the protruding side end of the feed body. A ratchet tooth is formed, and the second ratchet tooth is normally rotated until the first ratchet tooth moves along the tooth surface on one side with respect to the second ratchet tooth and contacts the tooth surface on the other side. Moreover, if this contact prevents the normal rotation of the second ratchet teeth, In addition, the fourth ratchet tooth is reversed until the second ratchet tooth or the third ratchet tooth moves along the tooth surface on one side with respect to the fourth ratchet tooth and contacts the tooth surface on the other side. Further, the tooth profile of each ratchet tooth is set such that the reversal of the fourth ratchet tooth is restricted by this abutment, and the first ratchet tooth meshes with the second ratchet tooth and the second ratchet tooth meshes with the second ratchet tooth.
Under the state where the ratchet teeth mesh with the fourth ratchet tooth, the third ratchet tooth is set to be in a semi-meshing state in which it can move along the tooth surface on one side with respect to the fourth ratchet tooth. .

[0014]

According to the above means, when the brake is released, the first ratchet tooth of the tubular body protruding from the piston is separated from the second ratchet tooth of the sheath rod outer cylinder. And the third ratchet teeth of the pressing body by the biasing force of the main spring member and the auxiliary spring member
It meshes with the ratchet teeth.

From such a state, when the piston is moved by the fluid pressure to perform the braking action,
First, the first ratchet tooth engages with the second ratchet tooth when the piston moves by a predetermined amount. At this time, the second ratchet tooth and the third ratchet tooth have a fourth
The meshing state with the ratchet teeth is maintained, but the third ratchet tooth is in the half meshing state. After this, the first,
When the piston further projects while the meshing of the second ratchet teeth is maintained, the brake shoe connected to the tip of the push rod is pressed against the wheel action surface to obtain the braking force.

In this case, when the second ratchet tooth is not separated from the fourth ratchet tooth when the piston reaches the projecting end, that is, when the stroke is within the reference stroke, the third ratchet tooth is the fourth ratchet tooth. Since the second ratchet tooth is in a half meshing state in which it can move along the tooth surface on one side, the fourth ratchet tooth tends to reverse due to the biasing force of the auxiliary spring member pressing the third ratchet tooth. When an urging force in the reverse rotation direction acts on the fourth ratchet tooth, the fourth tooth is formed on the other tooth surface that restricts movement in the reverse rotation direction.
Since the ratchet tooth and the second ratchet tooth are in contact with each other, the reverse rotation of the fourth ratchet tooth is restricted, and at the same time, the second ratchet tooth cannot cross over one tooth of the fourth ratchet tooth. Therefore, when the piston moves backward to release the brake from such a state, each ratchet tooth returns to the initial state.

On the other hand, when the second ratchet tooth separates from the fourth ratchet tooth at the time when the piston reaches the projecting end, that is, when the stroke exceeds the reference stroke, the fourth ratchet tooth meshes with the fourth ratchet tooth. Since only the third ratchet tooth is present, and the third ratchet tooth is not rotatable about the axis and is in a half meshed state, the third ratchet tooth causes the fourth ratchet tooth to move to the other side by the biasing force of the auxiliary spring member. Reverse until it contacts the tooth surface of. The second ratchet tooth meshes with the fourth ratchet tooth during the backward movement of the piston in order to release the brake from such a state. At this point, however, the fourth ratchet tooth is reversed as described above. The second ratchet tooth is in a state in which it can move over one tooth of the fourth ratchet tooth and move along the tooth surface on one side of the next tooth, that is, the state in which the fourth ratchet tooth can be reversed. At this time, the fourth ratchet tooth is meshed with the third ratchet tooth, so that the reverse rotation of the fourth ratchet tooth is restricted. Therefore, the second ratchet tooth is applied to the tooth surface on one side by the urging force of the main spring member. Along with that reaction, it rotates normally. As a result, the relative positions of the sheath rod outer cylinder and the push rod with respect to the axial direction change, and the gap between the brake shoe connected to the tip of the push rod and the wheel action surface is automatically adjusted.

[0018]

Embodiments of the brake cylinder with a clearance adjusting mechanism according to the present invention will be described below with reference to the drawings. Figure 1
1 shows a first embodiment of the present invention, in which a brake cylinder 1 includes a cylinder body 3 having a pressure fluid supply / discharge hole 2.
And is slidably fitted into the cylinder body 3 and is biased to the backward movement side (left side) by the return spring 4 so that the supply / discharge hole 2
A piston 5 that responds to the supply and discharge of pressure fluid from the piston 5, a tubular piston rod 6 that projects from the protruding movement side (right side) of the piston 5, and an axial center that is fitted on the inner peripheral side of the piston rod 6. A sheath rod 7 that is held so as to be rotatable about its axis and relatively movable in the axial direction by a predetermined dimension and has a tip projecting outward from the cylinder body 3, and a rear end portion screwed to the inner peripheral side of the sheath rod 7. And a push rod 8 to which a brake shoe (not shown) is connected. A cup packing P for maintaining airtightness is attached to the rear end of the piston 5.

The sheath rod 7 has a sheath rod outer cylinder 9 fitted and fixed by a key member K on the outer periphery thereof, and between the tip of the sheath rod outer cylinder 9 and the cylinder body 3. Is provided with a main spring member 10 and a thrust bearing 11 for urging the sheath rod outer cylinder 9 toward the backward movement side. Further, a ring-shaped pressing body 12 and a feeding body 13 are arranged on the outer peripheral side of the sheath rod outer cylinder 9. The pressing body 12 is movable in the axial direction and is biased to the backward movement side by the auxiliary spring member 14, and the pin member 15 fixed to the pressing body 12 is attached to the partition wall portion 3a of the cylinder body 3. By being inserted into the formed long hole 16, the pressing body 12 is not rotatable about the axis.
The feed body 13 is held by a partition wall portion 3a of the cylinder body 3 via a thrust bearing 17 so as to be rotatable about its axis and immovable in its axis direction.

FIG. 2 shows a disassembled arrangement state of the piston rod 6, the sheath rod outer cylinder 9, the pressing body 12, and the feeding body 13. The first ratchet teeth 21 are formed at the tip of the piston rod 6. The sheath rod outer cylinder 9 is formed with the second ratchet teeth 22 that mesh with the first ratchet teeth 21, the pressing body 12 is formed with the third ratchet teeth 23, and the feeding body 13 is formed with the second ratchet teeth 23.
4th that meshes with ratchet teeth 22 and 3rd ratchet teeth 23
Ratchet teeth 24 are formed.

The first to fourth ratchet teeth 21, 22, 23, 24
The tooth profile and meshing condition are set so as to perform the operations shown in FIGS. 3 to 6 described below.
It should be noted that FIGS. 3 to 6 are plan views of each component for convenience.

As shown in FIG. 3, the initial ratchet teeth 21 of the piston rod 6 and the second ratchet teeth 22 of the sheath rod outer cylinder 9 are set to a predetermined dimension m (predetermined rotation) in the brake slack state as an initial setting. Angle) and the second ratchet tooth 22 of the sheath rod outer cylinder 9 and the third ratchet tooth 23 of the pressing body 12 are urged by the urging force of the main spring member 10 and the auxiliary spring member 14 It is in full engagement with the thirteenth fourth ratchet tooth 24. And each ratchet tooth 21,22,23,2
The tooth surface on one side is inclined with respect to the axial direction, while the tooth surface on the other side is formed substantially along the axial direction.

From this state, when the piston rod 6 is projected to perform the braking action, the first ratchet tooth 21 is moved to the second ratchet tooth 21 when the piston rod 6 first projects by a predetermined dimension. One flank to ratchet tooth 22
When it moves along the (slope) and comes into contact with the tooth surface on the other side, as shown in FIG. 4, both ratchet teeth 21, 22 are in a completely meshed state. At this time, the second ratchet tooth 22 is normally rotated by the predetermined dimension m, and accordingly, the fourth ratchet tooth 22 is in contact with the second ratchet tooth 22 on the tooth surface on the other side.
The ratchet teeth 24 also rotate forward by a predetermined dimension m. Along with the normal rotation of the fourth ratchet tooth 24, the third ratchet tooth 23 is in a semi-engaged state in which the third ratchet tooth 23 is movable along the tooth surface on one side with respect to the fourth ratchet tooth 24, that is, the fourth ratchet tooth 24.
24 is in a half meshing state in which the predetermined size m can be reversed.

In this case, when the stroke of the piston rod 6 is less than the reference stroke S, the contact between the second ratchet tooth 22 and the fourth ratchet tooth 24 by the tooth surface on the other side is not released. When the piston rod 6 moves backward to loosen the brake from the state shown in FIG. 4 and the first ratchet tooth 21 separates from the second ratchet tooth 22,
When the auxiliary spring member 14 biases the third ratchet tooth 23 in the half meshed state, the fourth ratchet tooth 24 and the second ratchet tooth 24
The ratchet teeth 22 are reversed by the predetermined dimension m, and the state shown in FIG. 3 is restored. If the spring force of the main spring member 10 is made larger than that of the auxiliary spring member 14, the piston rod 6 moves backward from the state shown in FIG. 4 and the second ratchet teeth 22 separate from the first ratchet teeth 21. In such a case, the second ratchet tooth 22 and the fourth ratchet tooth 24 are meshed with each other without reversing, the third ratchet tooth 23 is still half meshed with the fourth ratchet tooth 24, and thereafter the piston rod Even if 6 moves in the protruding and retracting directions, the second ratchet teeth 22 do not rotate forward or backward by the predetermined dimension m as long as the movement is within the reference stroke S.

Next, when the stroke of the piston rod 6 exceeds the reference stroke S as shown in FIG. 5 due to the wear of the brake shoe, the second ratchet tooth 22 is separated from the fourth ratchet tooth 24. Because of the separation, the third ratchet tooth that was in the half meshed state is moved to the fourth position by the urging force of the auxiliary spring member 14.
The ratchet teeth 24 are reversed by the predetermined dimension m so that they are completely meshed with each other.

As the piston rod 6 moves backward from such a state, as shown in FIG.
22 is in a state where it can move over one tooth of the fourth ratchet tooth 24 and move along the tooth surface on one side of the next tooth. After that, when the first ratchet tooth 21 separates from the second ratchet tooth 22 due to the further backward movement of the piston rod 6, the second ratchet tooth 22 is attached to the tooth surface on one side of the fourth ratchet tooth 24. It moves along, but at this time, the 4th ratchet tooth
Since the third ratchet teeth 23 prevent the reverse rotation of 24, only the second ratchet teeth 22 are normally rotated by about one tooth due to the biasing force of the main spring member 10, and the sheath rod outer cylinder 9 and the sheath rod 7 are The piston rod 6 is relatively retracted. As a result, the stroke of the piston rod 6 becomes smaller than the reference stroke S again, and the clearance is automatically adjusted.

FIG. 7 shows a second embodiment of the present invention. The brake cylinder with a clearance adjusting mechanism 1 according to the second embodiment is substantially different from the first embodiment described above in that the outside of the sheath rod. The cylinder 9 and the sheath rod 7 are integrated, and the piston 5 is supported by the membrane plate 30. The other basic structure is the same as that of the first embodiment. Therefore, in the figure, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Although not shown in the drawing, the piston rod 6 has the first ratchet teeth, the sheath rod 7 has the second ratchet teeth, the pressing body 12 has the third ratchet teeth, and the feeding body 13 has the same ratchet teeth. Has a fourth ratchet tooth. Also in this second embodiment, as shown in FIG.
~ The same operation as in the state shown in Fig. 6 is performed.

[0028]

As described above, according to the brake cylinder with a clearance adjusting mechanism of the present invention, the first ratchet teeth formed on the tubular body of the piston (piston rod) and the sheath rod (sheath rod outer cylinder) are provided. The meshing condition of each of the formed second ratchet tooth, the third ratchet tooth formed on the pressing body, and the fourth ratchet tooth formed on the feed body is appropriately set from the time when the piston protrudes by a predetermined amount or more. Since the gap is automatically adjusted by changing it, only the ratchet teeth slide with the movement of the piston, and most of them have extremely small dimensions within one tooth. This is a corresponding portion, and therefore, the sliding resistance and the sliding time can be reduced, and the driving loss of the piston can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view showing the overall configuration of a first embodiment of a brake cylinder with a clearance adjusting mechanism according to the present invention.

FIG. 2 is a perspective view of parts disassembled arrangement showing the main components of the first embodiment.

FIG. 3 is a schematic view showing the action of the first embodiment in plan view.

FIG. 4 is a schematic view showing the action of the first embodiment in plan view.

FIG. 5 is a schematic plan view showing the operation of the first embodiment.

FIG. 6 is a schematic view showing the action of the first embodiment in plan view.

FIG. 7 is a vertical sectional front view showing the overall configuration of a second embodiment of the brake cylinder with a clearance adjusting mechanism according to the present invention.

FIG. 8 is a vertical cross-sectional view showing the overall structure of a conventional brake cylinder with a clearance adjusting mechanism.

[Explanation of symbols]

 1 Brake Cylinder with Gap Adjustment Mechanism 3 Cylinder Body 5 Piston 6 Tubular Body (Piston Rod) 7 Shear Rod 8 Push Rod 10 Main Spring Member 12 Pressing Body 13 Feeding Body 14 Auxiliary Spring Member 21 1st Ratchet Tooth 22 2nd Ratchet Tooth 23 23rd 3 ratchet teeth 24 4th ratchet teeth

Claims (1)

[Claims] 1. A push rod having a connecting portion for a brake shoe at its tip, a sheath rod screwed onto an outer peripheral side of the push rod so as to be rotatable around an axis, and a sheath rod housed in a cylinder body and the push rod. A fluid pressure responsive piston that causes the cylinder to project and retract in the axial direction with respect to the cylinder body, and in association with the movement of the piston, the sheath rod is rotated relative to the push rod about the axial center. In a brake cylinder having a clearance adjusting mechanism that changes the relative position of both of them with respect to the axial direction, a tubular body is provided so as to project on the protruding movement side of the piston, and the sheath rod is provided around the axial center on the inner peripheral side of the tubular body. Rotatably and axially relative to each other by a predetermined distance so that the sheath rod is urged toward the backward movement side by the main spring member, and the sheath rod is axially centered on the outer peripheral side. Movable and around the axis A pressing body that is held immovably and is urged toward the backward movement side by an auxiliary spring member, and a feeding body that is held so as to be rotatable about the axis and immovable in the axis direction are provided. A first ratchet tooth is formed at the end of the tubular body on the projecting side, and a second ratchet tooth that meshes with the first ratchet tooth when the piston projects by a predetermined dimension on the outer peripheral portion of the sheath rod.
A ratchet tooth is formed, a third ratchet tooth is formed at an end portion of the pressing body on the backward movement side, and a fourth ratchet tooth is meshed with the second ratchet tooth and the third ratchet tooth at an end portion of the feed body on the protruding movement side. And the second ratchet tooth is normally rotated until the first ratchet tooth moves along the tooth surface on one side with respect to the second ratchet tooth and contacts the tooth surface on the other side. The normal rotation of the second ratchet tooth is restricted by the abutment, and the second ratchet tooth or the third ratchet tooth moves along the tooth surface on one side with respect to the fourth ratchet tooth, and the tooth surface on the other side. The tooth profile of each ratchet tooth is set so that the fourth ratchet tooth reverses until it comes into contact with the first ratchet tooth, and the reverse rotation of the fourth ratchet tooth is restricted by this abutment. Mesh with ratchet teeth and Under the condition that the 2 ratchet teeth mesh with the 4th ratchet tooth, the 3rd ratchet tooth is set to be in a semi-meshing state in which it can move along the tooth surface on one side with respect to the 4th ratchet tooth. A characteristic brake cylinder with a clearance adjustment mechanism.