JPH0137238Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a braking device that prevents relative movement between a shaft and a bearing body that are relatively movable in the axial direction.

Background of the invention A shaft that moves in the axial direction is stopped at a predetermined position,
In various technical fields, it is often necessary to stop an object moving along an axis at a predetermined position on the axis. One of the typical examples is the air cylinder. Air cylinders use compressible air as the working fluid, so even if the air supply is cut off, the piston rod will not stop immediately.
The piston rod cannot be stopped at the correct position. Therefore, it cannot be stopped at an accurate position. Therefore, when it is necessary to stop the piston at an accurate position, conventionally, a fixed stopper has generally been provided, and the piston rod or a fixed member has been brought into contact with this stopper. However, in this case, it is difficult to arbitrarily change the stopping position, which is why a braking device is needed. In addition, in order to make the moving platform guided by the guide rod in the same state as if it were fixed to the frame at an arbitrary position,
A braking device is required in various fields, such as when preventing relative movement between a guide rod and a moving table.

Purpose of the invention In view of these needs, the present invention was made with the purpose of providing an axial braking device that has a simple structure, can be constructed in a small size, and can provide sufficient response speed and braking force. It is.

Structure of the Invention In order to achieve this object, an axial braking device according to the present invention is a braking device that prevents relative movement between a shaft that is relatively movable in the axial direction and a bearing body, and includes:
(1) a tubular cylinder that is provided immovably relative to the bearing body and through which the shaft passes through with a clearance; (2)
(3) at least one piston having an annular shape and having an outer circumferential surface fitted into the cylinder and an inner circumferential surface fitting into the shaft in an airtight and slidable manner; and (3) at least one piston having a cylindrical shape and formed in the axial direction. (4) a brake shoe having a radially retractable slit, which is fitted onto the shaft and fixed to the cylinder so as not to be relatively movable in the axial direction; and (4) having a disc spring shape as a whole. None, the inner circumferential edge is fitted onto the outer circumferential surface of the brake shoe and compressed in the axial direction by the piston to tighten the brake shoe, and the inner circumferential edge of the brake shoe is fitted onto the outer circumferential surface of the shaft. (5) a spring member that biases the piston in a direction in which the clamping member is compressed; (6) a spring member that biases the piston in a direction in which the clamping member is compressed; (7) a first cam section provided on the piston; (8) an operating section and a second cam section; The second cam part engages with the first cam part by the operating force applied to the operating part, and moves the piston in a direction in which the compression action on the tightening member is released. A cam member.

Note that the term "bearing body" here includes not only a literal bearing device that supports a shaft so that it can slide in the axial direction, but also a part that is fitted with the shaft of an object that is guided by a fixed shaft. Used as a term for a broad concept. In addition, the tubular cylinder that is immovable relative to the bearing body is not limited to a cylindrical body.
There are also cylinders that are constructed independently with a cover that closes both ends and are used by being attached to a separately provided bearing body, and furthermore, cylinders that are constructed so that one or both of the covers also serve as the bearing body. shall mean.

Effects of the invention In the braking device configured in this way, the brake shoe is pressed against the shaft by a compact and simple-structured tightening member, so the overall structure is simple, compact, and inexpensive. A braking device is obtained. Furthermore, since the tightening member can tighten the brake shoe in response to an extremely small operating stroke of the piston, a highly responsive braking device can be obtained, and the volume of the pressure chamber in the cylinder can be reduced. Even when the working fluid is gas, the delay in actuation due to compressibility is reduced, and a braking device with sufficient response speed can be obtained.

Furthermore, in such a device, even if pressure fluid is not normally supplied to the cylinder,
When the cam member is operated, the piston is moved against the biasing force of the spring member, and the brake on the shaft is released. Therefore, since the shaft can be moved manually, the braking action can be canceled even in the event of a failure of the pressure fluid supply device, piping system, power outage, etc.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an example of a braking device for stopping a piston rod of an air cylinder at an arbitrary position. In the figure, reference numeral 10 denotes a cylinder forming the main body of the braking device, which is detachably attached to a rod cover 12 of the air cylinder. The cylinder 10 has a square outer shape and a circular bottomed hole in the center, and includes a first tube 14 and a second tube 16, which are arranged with the opening sides of the bottomed holes facing each other. An annular first piston 18 and an annular second piston 20 are fitted in the respective tubes 14 and 16 in an airtight and slidable manner. Between the open ends of the pair of tubes 14 and 16 is a port member 24 equipped with a first port 22 for letting air in and out of the cylinder, and on the bottom side of the second tube 16 is a rod cover 2.
6 are arranged respectively. The radial position of the rod cover 26, the port member 24, the first tube 14, and the second tube 16 is determined by the fitting between the respective fitting holes and the fitting protrusions, and the rod cover 26, the port member 24, and the first tube 14 and the second tube 16 are provided through the fitting hole and the fitting protrusion. It is fixed to the rod cover 12 of the air cylinder by bolts 28 and nuts 30, thereby forming an integral cylinder 10. In this example, the end faces of each of these members are ground flat and the end faces are brought into close contact to maintain airtightness between the members, but packing, O-rings, etc. Of course, it is also possible to maintain airtightness using a sealing member.

The piston rod 32 of the air cylinder extends through the cylinder 10 and both pistons 18 and 20;
Air cylinder air cylinder rod cover 12
It is held by seal members 34 and 36 provided on the rod cover 26 of the cylinder 10 and seal members 38 and 40 provided on the rod cover 26 of the cylinder 10.

A through hole 42 is formed in the center of the bottom of the second tube 16 . The inner diameter of the through hole 42 is made larger than the outer diameter of the piston rod 32, and an annular gap is formed between the inner circumferential surface of the through hole 42 and the outer circumferential surface of the piston rod 32, and the brake shoe 44 is inserted into the gap. It is arranged. As is clear from FIG. 3, the brake shoe 44 is a cylindrical member with a single axial slit 46 formed therein so that the diameter can be reduced by elastic deformation. The brake shoe 44 usually has an outer peripheral surface formed by the second tube 16.
The piston rod 32 is in close contact with the inner circumferential surface of the through hole 42, and a minute clearance is formed between its inner circumferential surface and the outer circumferential surface of the piston rod 32. This brake shoe 44 is equipped with an annular projection 48 at one end,
This protrusion 48 is fitted into a counterbore formed at one end of the through hole 42. The protrusion 48 is sandwiched between the bottom surface of the counterbore and the end surface of the fitting protrusion 50 of the rod cover 26 on both front and rear surfaces, thereby making it impossible to move relative to the cylinder 10.

The end of the brake shoe 44 opposite to the side on which the protrusion 48 is formed is pushed a certain length into the front pressure chamber 52 formed on the front side of the second piston 20. A tightening member 54 in the shape of a disc spring is fitted onto the outer circumferential surface of the secured portion.
As shown in FIG. 4, the tightening member 54 has a plurality of notches 56 radially formed at equal angular intervals on its inner circumferential edge, and also has radial notches 5 formed from its outer circumferential edge.
8 are formed at equal angular intervals. The larger diameter side of the tightening member 54 is fitted into a counterbore hole 60 formed in the front end surface of the second piston 20. As shown in FIG. 5, a shallow annular groove 62 is formed on the outer periphery of the bottom surface of the counterbore hole 60.
When the peripheral edge of the tightening member 54 is fitted into the second piston 20 and the second piston 20 moves in the axial direction, the tightening member 5
The periphery of 4 can be moved together.

The brake shoe 44 and the tightening member 54 constitute the second braking part 64 together with the second piston 20 and the second tube 16, but the brake shoe 66 and the tightening member are also provided on the first piston 18 side. 68 is disposed to constitute the first brake section 70 together with the first tube 14.

Rear pressure chambers 72 and 74 are formed in the pair of pistons 18 and 20, and these pressure chambers 7
One end of each compression coil spring 76, which is disposed with a predetermined preload, is brought into contact with the bottom surface of each of the pistons 18, 20.
is biased toward the front. This pressure chamber 72, 74
is communicated with the first port 22 via a communication passage 78 formed between the pistons 18 and 20, and air pressure for pushing the pistons 18 and 20 forward is introduced. It's summery.

On the other hand, the first tube 14 and the second tube 1
6 is provided with a second port 80, and air pressure is introduced from this second port 80 into the front pressure chambers 52, 82 in order to move the pistons 18, 20 rearward.

At the rear portions of the pistons 18 and 20, semicircular cam portions 84 and 86 are provided so as to protrude rearward from each other, and a semicircular cam member 88 is provided opposite to the cam portions 84 and 86. is installed. At both circumferential ends of the cam portions (first cam portions) 84 and 86, cam members 8 are disposed as they move toward the rear side.
Inclined cam surfaces 90 and 92 extending toward the side of 8 are formed, and the cam member 88 has a cam portion having cam surfaces 94 and 96 that face and are substantially parallel to these cam surfaces 90 and 92. (Second cam part) 97
is formed. A small diameter end portion of a bolt 98 screwed into the port member 24 is fixed to the cam member 88 in a relatively rotatable state by a snap spring 100. By rotating the bolt 98, the cam member 88 is rotated as shown in the figure. It is designed to be moved up and down. That is, the bolt 98 is configured as an operating portion of the cam member 88. In addition, the snap spring 100 is a bolt 98.
It is elastically fitted into an annular groove formed at the tip of the 101 is a lock nut.

The braking device configured as described above is used by being connected to an air source 104 via the electromagnetic directional valve 102. As the air source 104, an air source for operating an air cylinder to which this braking device is attached can be used, and in this case, a braking force proportional to the operating force of the piston rod 32 will be obtained. . This is because both the actuation force and the braking force are proportional to the pressure of the air supplied from the air source 104. The electromagnetic directional valve 102 normally connects the rear pressure chambers 72 and 74 to the air source 104,
The front pressure chambers 52, 82 are in a state of being opened to the atmosphere. Therefore, in such a state, the air source 104
When air is supplied from the pistons 18 and 2
0 is the biasing force of the spring 76 and the rear pressure chamber 7
It is pushed forward by the air pressure acting on 2 and 74. As a result, on the second piston 20 side, the tightening member 54 is compressed in the axial direction between the second tube 16 and the second piston 20. The tightening member 54 originally has a property that when compressed in the axial direction, the outer diameter expands and the inner diameter contracts. Since it is regulated by the bottom surface of the annular groove 62 formed on the circumferential surface, more precisely on the inner circumferential surface, the inner diameter is particularly reduced. Therefore, due to the contraction of the inner diameter, the brake shoe 44 is contracted and pressed against the outer peripheral surface of the piston rod 32 to prevent relative movement of the piston rod 32 with respect to the brake shoe 44. Moreover, this brake shoe 4
As described above, since the piston rod 32 is attached in such a manner that it cannot move relative to the cylinder 10 in the axial direction, the piston rod 32 is ultimately prevented from moving relative to the cylinder 10 in the axial direction.

On the other hand, the tightening member 6 is also
8 is axially compressed and tightens the brake shoe 66 to prevent axial movement of the piston rod 32. In other words, the braking device of this embodiment is a constant braking type device.

Note that if the braking force applied to the piston rod 32 does not need to be so large, the supply of air to the rear pressure chambers 72 and 74 can be omitted. In this case, there is an advantage that the switching valve 102 can be a 3-port, 2-position switching valve.

On the other hand, when it is necessary to move the piston rod 32, the electromagnetic directional control valve 102 is switched to introduce air pressure from the air source 104 into the front pressure chambers 52, 82, and the rear pressure chambers 72, 7.
4 air pressure is released into the atmosphere. As a result, the pistons 18 and 20 are moved backward against the biasing force of the spring 72, and the tightening members 54 and 68
Remove the compression effect on. As a result, the small diameters of both clamping members 54, 68 are enlarged, allowing the piston rod 32 to move freely. The operating strokes of the pistons 18 and 20 required for this purpose are extremely small, so that the front pressure chamber 5
2 and 82 can be made small in volume, and a delay in the operation of the braking device due to the compressibility of air can be eliminated.

When the piston rod 32 has moved to a predetermined position and it becomes necessary to stop it again, the power supply to the solenoid of the switching valve 102 is cut off and the switching valve 102 is switched again to the state shown in FIG. It will be done. As a result, the front pressure chambers 52 and 82 are opened to the atmosphere, air is supplied to the rear pressure chambers 72 and 74, the pistons 18 and 20 are moved forward, and the tightening members 54 and 68 are compressed. do. Compression of the clamping members 54, 68 causes the brake shoes 44, 66 to contract, bringing the piston rod 32 to rest again. This braking device also has excellent responsiveness in this case.

The effect of braking and releasing the braking on the piston rod 32 using air pressure has been explained above, but this device controls the biasing force of the coil spring 76 and the pistons 18 and 20 by screwing in and operating the bolt 98. It has a feature that the braking of the piston rod 32 can be released regardless of the driving force based on the applied fluid pressure. That is, when the bolt 98 is screwed in, the cam member 8
8 engages with piston cam portions 84 and 86 to forcibly move pistons 18 and 20 toward each other, thereby releasing the brake on piston rod 32. Therefore, in this device, even if the piston rod 32 is automatically braked by the biasing force of the spring 76 due to a failure of the switching valve 102, a failure of the piping for circulating air, a power outage, etc. , the braking action is released by operating the bolt 98, and the piston rod 32
can be moved to a desired position.

In addition, the cam shape of the cam member and piston cam part,
Alternatively, the operating section can be configured in various other ways, and the present invention can be implemented with various modifications based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing a constantly braking type braking device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken from the side in FIG. 1. 3 and 4 are diagrams showing the brake shoe and the tightening member in FIG. 1, respectively, and FIG. 5 is a cross-sectional view of the main part showing the tightening member and its surroundings in FIG. 1 on an enlarged scale. It is a diagram. 10...Cylinder, {18...First piston,
20...Second piston} (piston), 44, 66
... Brake shoe, 54, 68 ... Tightening member,
76... Coil spring, 84, 86... Cam part (first cam part), 88... Cam member, 97...
Cam part (second cam part) 98... Bolt (operating part).

Claims (1)

[Claims for Utility Model Registration] A braking device that prevents relative movement between a shaft that is relatively movable in the axial direction and a bearing body, the braking device being provided so as not to be movable relative to the bearing body, and the shaft having a play. a tubular cylinder penetrated by a cylinder; a piston having an annular shape and having an outer circumferential surface fitted into the cylinder and an inner circumferential surface fitting into the shaft in an airtight and slidable manner; a brake shoe having at least one slit formed in the radial direction, the brake shoe being retractable in the radial direction, fitted to the shaft and fixed to the cylinder so as not to be relatively movable in the axial direction; The inner circumferential edge is fitted into the outer circumferential surface of the brake shoe and tightens the brake shoe by being compressed in the axial direction by the piston, and the inner circumferential surface of the brake shoe a clamping member that presses the piston against the outer peripheral surface of the shaft; a spring member that biases the piston in a direction in which the clamping member is compressed; and a spring member that biases the piston against the biasing force of the spring member to compress the clamping member. a pressure fluid supply device that supplies pressure fluid to the cylinder in order to move the piston in a direction to release the compression effect on the piston; a first cam portion provided on the piston; an operating portion and a second cam portion; a cam member that causes the second cam portion to engage with the first cam portion and move the piston in a direction in which the compressive action on the tightening member is released by an operating force applied to the operating portion; An axial braking device characterized by: