JP2001173610A - Rodless cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rodless cylinder at low cost with a small number of parts in addition capable of preventing a bad influence on an equipment by relaxing a shock in case a shock absorber is inoperative due to any reason. SOLUTION: A pair of scrapers 7 are provided in both ends of a driven unit 5 driven by a piston by a driving magnet 41 arranged in the piston, each scraper 7 comprises a plate abutting to an end face of an annular slide member 53 fitted to both end internal peripheries of the driven unit 5 and a rubber-state elastic member connected to this plate to be capable of elastically abutting to an end member 3, a lip part into slide contact with an external peripheral surface of a cylinder tube 1 and a buffer protrusion part protruded to a side of the end member 3 from this lip part are formed in this rubber-state elastic member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure driven rodless cylinder used for driving equipment, transporting objects, and the like.

[0002]

2. Description of the Related Art A typical prior art of a rodless cylinder which eliminates the need for a piston rod by using a magnet is disclosed, for example, in Japanese Utility Model Publication No. 6-25684.

In the rodless cylinder according to the prior art, end members are fixed to both ends of a cylinder tube and a guide shaft which are parallel to each other, and a piston having a driving magnet is slidably inserted into the cylinder tube.
A driven magnet is provided outside the cylinder tube, and a driven body guided by the guide shaft is slidably provided.When a piston in the cylinder tube is slid under the action of a pressure fluid, The driven body is configured to move by the magnetic force of the driving magnet and the driven magnet.

A shock absorber having a retractable plunger for receiving a stopper receiver provided on the driven body is disposed on the end member. That is, when the driven body reciprocated between the two end members reaches a position short of the stroke end, the impact is absorbed by the stopper receiver being elastically received by the plunger. Stops when it comes into contact with the end face of the shock absorber.

[0005]

However, the following problems are pointed out in the rodless cylinder according to the prior art. That is, this kind of rodless cylinder includes a driven magnet row in which driven magnets and an outer yoke are alternately arranged, and the driven magnet row is a holding member on which a scraper and an annular sliding member are mounted. In the driven body, is fitted into the cylinder insertion hole of the driven body, and the holding member is locked by a retaining ring for a hole via a pressing plate. Therefore, since a scraper and a holding member for arranging the annular sliding member that are in sliding contact with the outer peripheral surface of the cylinder tube are required, the number of components is large, the assembly is complicated, and the manufacturing cost is high.

Further, as described above, when the driven body approaches the stroke end, the shock absorber absorbs the impact, and then the stop surface comes into contact with the end surface of the stopper receiver and the end surface of the shock absorber. If the shock absorber is mounted at a position retracted from a predetermined position or is not mounted, the end surface of the end member collides with the end surface of the driven body at the stroke end. For this reason, a large inertial force acts on the rodless cylinder, which may cause a malfunction in the equipment.

Such a situation occurs, for example, when a worker at the site adjusts the equipment when the shock absorber is retracted due to a short stroke or when the shock absorber is removed in order to increase the cycle time. As a result, the rodless cylinder itself is often damaged by the above-mentioned collision. Further, in the case where the test operation is performed in a state where the position of the shock absorber is retracted, even a single collision may cause looseness in the linear bearing that supports and guides the driven body.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a main technical problem thereof is to provide an inexpensive rodless cylinder with a reduced number of parts. Another technical problem is to provide a rodless cylinder that can reduce impact and prevent adverse effects on equipment even when the shock absorber does not operate for some reason.

[0009]

As a means for effectively solving the above-mentioned technical problems, a rodless cylinder according to the present invention comprises: a cylinder tube made of a non-magnetic material;
A pair of end members respectively attached to both ends of the cylinder tube, a piston inserted axially movably on an inner periphery of the cylinder tube, a driving magnet disposed on the piston, and the cylinder tube A driven body externally movably inserted in the outer periphery of the driven body and driven by the piston by the magnetic force of the driving magnet, a pair of scrapers are provided at both ends of the driven body, Each of the scrapers is a plate that comes into contact with an end surface of an annular sliding member fitted into the inner periphery of both ends of the driven body, and is joined to this plate and slidably contacts the outer peripheral surface of the cylinder tube, and is elastically connected to the end member It is made of a rubber-like elastic member that can be brought into contact with each other.

In the above structure, more preferably, the rubber-like elastic member of the scraper is formed with a lip portion that is in sliding contact with the outer peripheral surface of the cylinder tube and a buffer projection that protrudes toward the end member beyond the lip portion. .

[0011]

1 to 5 show a rodless cylinder according to the present invention. In these figures, reference numeral 1 denotes a cylinder tube, 2 denotes a guide rail, and these cylinder tube 1 and guide rail 2
The end members 3, 3 arranged at both ends in the longitudinal direction are fixed in a state parallel to each other.

A piston 4 is provided on the inner periphery of the cylinder tube 1.
Is inserted so as to be movable in the axial direction, and the cylinder tube 1 is
A driven body 5 driven by the piston 4 is externally movably mounted on the outer periphery of the body. A guide block 6 is fixed to the driven body 5 so as to be relatively displaceable with respect to the guide rail 2 in the longitudinal direction.

The cylinder tube 1 is a cylindrical member made of a non-magnetic material, and both ends in the axial direction are loosely fitted into fitting holes 31 formed in the end member 3, respectively. Are sealed by an O-ring 32 between the inner circumferential surface of the cylinder tube and both end portions of the cylinder tube 1 inserted therein.

An orifice 33 and a pressure supply / discharge port 34 extend coaxially from the insertion holes 31 into which the both ends of the cylinder tube 1 are inserted.
A pressure fluid (for example, compressed air) supply source (not shown) is connected to the pressure supply / discharge ports 34 and 34 via a switching valve and piping (not shown).

The piston 4 has a plurality of annular or cylindrical driving magnets 41 and a plurality of inner yokes 42 each having a hole penetrating in the axial direction at an axial center portion, and the driving magnets 41 are alternately arranged in the axial direction to form a driving magnet row. A pair of piston members 44, 44 are provided at both ends of a tie rod 43 inserted through the center hole of the driving magnet row.
Are integrated by screwing and binding.
A piston seal 45 and a wear ring 46, which are in close contact with the inner peripheral surface of the cylinder tube 1, are mounted on the outer peripheral surfaces of the piston members 44, 44, respectively.

The driven body 5 is made of a magnetic material. As shown in FIG. 3, the driven body 5 is annularly protruded from the inner peripheral surface of the cylinder insertion hole 51 through which the cylinder tube 1 is freely inserted, and has an inner diameter of the above-mentioned. Outer yokes 52 that are close to the outer peripheral surface of the cylinder tube 1 with a small gap are formed with the same number and the same intervals as the inner yokes 42 of the piston 4. A pair of annular sliding members 53 are fitted to the inner peripheral surfaces of both ends of the cylinder insertion hole 51 so that the outer yoke 52 and the cylinder tube 1 are held concentrically with each other via a predetermined gap. Has been inserted.

That is, the driven body 5 is guided by the guide rail 2 via the guide block 6, and an outer yoke 52 formed on the inner peripheral surface of the cylinder insertion hole 51.
Inner yoke 42 of driving magnet array in piston 4
Are moved together with the piston 4 by a magnetic attraction force acting between them.

As shown in FIG. 1, a required number of taps 5 for fixing a work or a tool are provided on the upper surface of the driven body 5.
4 are provided. Further, a circular hole 55 and a long hole 56 for inserting a positioning pin provided on the workpiece or the tool.
Is provided so that when the work or tool is removed from the driven body 5 and then mounted again, reproducibility of the mounting position can be ensured.

The end members 3 and 3 and the guide rail 2 are provided with mounting holes 21 and 35 for mounting the rodless cylinder to equipment and the like.

A cylinder insertion hole 5 into which the cylinder tube 1 is inserted is provided at both end surfaces 5a and 5b in the moving direction of the driven body 5.
1, a pair of scrapers 7, 7
Are fixed respectively. Each of the scrapers 7 includes a plate 71 made of a metal plate such as SPCC and a rubber-like elastic member 72 made of urethane rubber or the like baked on one side of the plate 71, as shown more clearly in FIGS. The rubber-like elastic member 72 has an inner peripheral lip portion 72a that slides on the outer peripheral surface of the cylinder tube 1.
And a buffer protrusion 72b on the outer peripheral side protruding outward from the lip 72a.

The lip portion 72a of the scraper 7 is continuous in the circumferential direction and has a tapered protruding shape. Dust and foreign matters adhering to the outer peripheral surface of the cylinder tube 1 enter the driven body 5. To prevent The buffer protrusions 72b are formed so as to be intermittent at regular intervals in the circumferential direction, that is, a groove 72c extending radially around the axis of the cylinder tube 1 is formed between the buffer protrusions 72b, 72b. ing.

Each of the scrapers 7 is provided with a small screw 73 (see FIG. 4 and the like) in small holes 71a, 71a formed at a pair of projecting ends of the plate 71, and the end faces 5a, 5
b is attached to the driven body 5 by screwing into a female screw hole formed in the hole b or by a hole retaining ring (not shown). Therefore, as in the case of the prior art, there is no need for a housing member or the like that holds the scraper made of a single rubber-like elastic body together with the annular sliding member at both ends of the cylinder insertion hole, which reduces the number of assembling steps. Also, parts costs are reduced. Further, compared to a scraper made of a single rubber-like elastic body, the length can be reduced in the longitudinal direction, so that the overall length of the rodless cylinder can be shortened.

Further, the scraper 7 has a function of preventing intrusion of dust and foreign matter by the lip portion 72a as described above,
In addition to the buffering function of the buffering projection 72b, as shown in FIG. 3, the plate 71 is provided with an annular sliding member 5 mounted on the inner peripheral surfaces of both ends of the cylinder insertion hole 51 of the driven body 5.
3 and 53, the annular sliding member 5
It also has a function to prevent the dropping of No.3. Therefore,
There is no need to separately provide a means for holding the annular sliding member 53 in the cylinder insertion hole 51.

Each end member 3 is provided with a screw hole 36 penetrating in a direction parallel to the moving direction of the driven body 5, and the shock absorber 8 is screwed into the screw member 36 so as to pass through the screw hole 36. ing. That is, a screw groove is formed on the outer periphery of the shock absorber 8, and the shock absorber 8 is fixed to the screw hole 36 by a lock nut 81 so that the position can be adjusted.

The shock absorber 8 includes the driven body 5
And a plunger 82 which can be protruded and retracted from the opposite end of the plunger 82. The plunger 82 is always elastically urged in a projecting direction toward the driven body 5 by an internal urging means (not shown). On the other hand, a stopper receiver 9 is provided at a position in the driven body 5 opposite to the shock absorber 8 in the axial direction.

The rodless cylinder configured as described above operates as follows.

First, in FIGS. 1 to 3, compressed air as a working fluid is supplied from a compressed air supply source (not shown) by the operation of a switching valve to the right end member 3 (3
L), the pressure is supplied to the right cylinder chamber 1R in the cylinder tube 1 through the pressure supply / discharge port 34 and the orifice 33, and the left cylinder chamber 1
L is released to the atmosphere through the orifice 33, the pressure supply / discharge port 34, and the switching valve in the left end member 3 (3L) in the figure, so that the piston 4 moves inside the cylinder tube 1 to the left. Is stopped at the stroke end position where it comes into contact with the end face 8a of the shock absorber 8 on the left side in the figure.

Here, a load from a work or a tool mounted on the upper surface of the driven body 5 is applied to a guide block 6 fixed to the driven body 5 and a guide block mounted on a frame such as equipment. Since the driven body 5 is supported by the ball bearing, the driven body 5 is not displaced even when an external force acts on the driven body 5 at the stroke end. Further, even if the rodless cylinder is operated in this load supporting state, the driven body 5 can be smoothly displaced relative to the guide rail 2 in the longitudinal direction.

Next, by a switching operation of a switching valve (not shown), the left side cylinder chamber 1L in the cylinder tube 1 in the cylinder tube 1 is passed through the pressure supply / discharge port 34 and the orifice 33 in the left end member 3 (3L) in the figure. And the cylinder chamber 1R on the right side in the figure is opened to the atmosphere through the orifice 33, the pressure supply / discharge port 34, and a switching valve (not shown) in the end member 3 (3R) on the right side in the figure. 4 moves rightward in the cylinder tube 1. The driven body 5 externally inserted into the cylinder tube 1 includes outer yokes 52 formed on the inner peripheral surface of the cylinder insertion hole 51 and an inner yoke 42 provided on the driving magnet row of the piston 4. Driven by the movement of the piston 4 by the magnetic attraction force acting between
Move to the right.

When the driven body 5 reaches near the stroke end, the stopper receiver 9 provided on the right end face 5b of the driven body 5 allows the shock absorber 8 provided on the end member 3 to come and go. The impact is absorbed by contacting the tip of the plunger 82. Thereafter, the driven body 5 moves while pushing the plunger 72 into the interior of the shock absorber 8 against the urging force of the urging means, and the stroke in which the stopper receiver 9 and the end face of the shock absorber 8 come into contact with each other. Stop by reaching the end.

Further, for example, when a worker at the site adjusts the equipment, the shock absorbers 8, 8 may be fixed at a position retracted from a predetermined position due to a short stroke.
Shock absorber 8,8 to increase cycle time
When the driven body 5 reaches the stroke end, the rubber-like elastic member 72 of the scraper 7 is removed.
Of the end member 3 comes into contact with the end surface of the end member 3. Then, the shock-absorbing protrusion 72b is elastically deformed, thereby reducing the inertial force of the driven body 5 and absorbing a shock. Further, the cushioning projection 72b is connected to the cylinder tube 1
Since it is provided coaxially, no moment load is generated by the cylinder thrust at the time of stop.

Therefore, at the stroke end,
When the end face of the end member 3 collides with the end face of the driven body 5, a large inertia force acts on the rodless cylinder,
It is possible to effectively prevent problems such as malfunctioning of the equipment, rattling of the linear bearing that supports and guides the driven body 5, and damage to the rodless cylinder itself.

When the cushioning projection 72b of the scraper 7 is in contact with the end surface of the end member 3, a gap interposed between the cushioning projection 72b and the cylinder tube 1 on the inner periphery thereof is formed by each cushioning projection. Radial groove 72c between portions 72b
The end member 3 is not adsorbed to the external space since the end member 3 is communicated with the external space through the interface. Therefore, when the piston 4 starts moving from the stop state, the driven body 5 is driven with good responsiveness.

Note that the buffer protrusion 7 of the scraper 7
The number of 2b, in other words, the number of grooves 72c is not particularly limited, and various shapes such as a columnar shape of the buffer protrusion 72b can be considered.

Similar effects can be obtained by using a conventional structure in which a driven magnet array in which driven magnets and outer yokes are alternately arranged is fitted to the driven body 5 as in the conventional case. In this case, there are many components, the assembly is complicated, and the manufacturing cost is high. On the other hand, according to the configuration of the above embodiment, the magnetic attraction force is obtained between the outer yoke 52 formed on the inner peripheral surface of the cylinder insertion hole 51 and the inner yoke 42 of the driving magnet row in the piston 4. Therefore, the number of parts of the driven body 5 can be significantly reduced.

[0036]

As described above, according to the rodless cylinder of the present invention, a housing member for holding the scraper together with the annular sliding member at both ends of the cylinder insertion hole is not required, and the scraper plate is not required. However, since it also has the function of preventing the annular sliding members attached to the inner peripheral surfaces at both ends of the cylinder insertion hole of the driven body from falling off, the number of assembly steps is reduced, and the cost of parts is also reduced. Also, compared to a case where a rubber scraper is mounted in a housing or the like,
Since the mounting length can be shortened, the overall length of the rodless cylinder can be shortened accordingly.

If the shock absorber at the stroke end cannot provide a shock-absorbing function because the shock absorber is mounted at a position retracted from a predetermined position or is not mounted, In this case, since the end surface of the end member and the rubber-like elastic member of the scraper come into contact with each other, it is possible to prevent a large inertial force from acting on the rodless cylinder and to prevent troubles in the equipment. Moreover,
Since the scraper, more specifically, the cushioning protrusion of the rubber-like elastic member is provided coaxially with the cylinder tube, an effect that no moment load is generated by the cylinder thrust at the time of stopping is realized.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a rodless cylinder according to the present invention.

FIG. 2 is a side view in the direction of arrow II in FIG.

FIG. 3 is a sectional view taken along the line III-III ′ in FIG. 1;

FIG. 4 is a sectional view taken along the line IV-IV 'in FIG.

FIG. 5 is a sectional view taken along line V-V 'in FIG.

FIG. 6 is a perspective view of the scraper in the embodiment.

FIGS. 7A and 7B show the scraper according to the embodiment, wherein FIG. 7A is a view seen from the axial direction, and FIG. 7B is a cross-sectional view taken along the line BB ′ in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder tube 2 Guide rail 21, 35 Mounting hole 3 End member 31 Fitting insertion hole 32 O-ring 33 Orifice 34 Pressure supply / discharge port 4 Piston 41 Driving magnet 42 Inner yoke 43 Tie rod 44 Piston member 45 Piston seal 46 Wear ring 5 Cover Driver 51 Cylinder insertion hole 52 Outer yoke 53 Annular sliding member 54 Tap 55 Circular hole 56 Long hole 6 Guide block 7 Scraper 71 Plate 71a Small hole 72 Rubber-like elastic member 72a Lip portion 72b Buffer protrusion 72c Groove 8 Shock absorber 81 Lock nut 82 Plunger 9 Stopper receiver

Claims (2)

[Claims] 1. A cylinder tube (1) made of a non-magnetic material, a pair of end members (3, 3) attached to both ends of the cylinder tube (1), and an inner periphery of the cylinder tube (1). A piston (4) inserted in the piston (4) so as to be movable in the axial direction, and a driving magnet (41) disposed on the piston (4)
And a driven body (5) externally movably mounted on the outer circumference of the cylinder tube (1) and driven by the piston (4) by the magnetic force of the driving magnet (41). In the cylinder, a pair of scrapers (7,
7), wherein each of the scrapers (7) comprises: a plate (71) abutting on an end face of an annular sliding member (53) fitted into the inner periphery of both ends of the driven body (5); A rod-less cylinder, which is made of a rubber-like elastic member (72) which is joined to the outer peripheral surface of the cylinder tube (1) and which is elastically contactable with the end member (3). . 2. A rubbery elastic member (7) of a scraper (7).
2), a lip portion (72a) that is in sliding contact with the outer peripheral surface of the cylinder tube (1), and a buffer protrusion (72b) that protrudes toward the end member (3) beyond the lip portion (72a). The rodless cylinder according to claim 1, wherein: