JP3474490B2 - Fluid pressure cylinder device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure cylinder device used as an injection cylinder of an injection molding machine.

[0002]

2. Description of the Related Art Generally, an injection cylinder used in an injection molding machine operates at a very high speed when a piston rod moves forward. Therefore, an accumulator for supplying a large amount of pressure oil is often used.

Since the piston rod operates at high speed, it is necessary to use a cushion mechanism having a sufficient cushion action at the stroke end in order to absorb the impact at the stroke end.

Conventionally, a cushion mechanism by meter-out control has been adopted in which the pressure oil in the cylinder chamber at the stroke end is confined and the pressure oil is discharged through the throttle passage.

[0005]

However, as described above, since the piston rod operates at high speed and the effective pressure receiving area on the rod side is usually set small,
The pressure of the pressure oil trapped in the cylinder chamber on the rod side due to the cushioning action becomes extremely high. Therefore, it is necessary to make the cylinder tube, the rod cover, and the like strong enough to withstand high pressure, and the shape and weight tend to increase.

On the other hand, it is conceivable to reduce the diameter of the piston rod to increase the effective pressure receiving area on the rod side, thereby lowering the maximum pressure generated in the cylinder chamber on the rod side. However, in that case, the flow rate of the return pressure oil during the operation of the piston rod increases, so that a load may be applied to the filter or the like provided in the return pipe line of the hydraulic unit, which may cause damage.

The present invention has been made in view of the above-mentioned problems, and is configured so that a cushioning action due to meter-in occurs in the cylinder chamber on the head side, and a fluid pressure capable of obtaining a sufficient cushioning action at the stroke end. An object is to provide a cylinder device.

[0008]

According to a first aspect of the present invention, there is provided a cylinder tube, a piston that slides in the cylinder tube, a piston rod that moves integrally with the piston, and a head-side end surface of the cylinder tube. A head cover that closes the rod side end surface of the cylinder tube, and an oil feed pipe provided in the head cover so as to project into the cylinder chamber is provided in a hole provided in the piston rod and the piston. a fluid pressure cylinder device that is configured to be inserted, to form a throttle channel by meter between the outer peripheral surface of the distal end near the oil feed tube and the inner peripheral surface near the entrance of the hole, the diaphragm The flow path is provided on the side close to the entrance of the hole.
Diameter small throttle hole, diameter provided on the side far from the entrance of the hole
Large throttle hole, provided on the side close to the tip of the oil feed pipe
Large-diameter boss that fits in the large-throttle hole, and the oil feed pipe
Diameter that is provided on the side far from the tip and that fits into the small diameter throttle hole
Formed by a small throttle boss and delivered from the oil pipe
Of the pressure liquid between the large-diameter throttle boss and the small-diameter throttle boss.
It is configured to flow into the hole from a flow passage provided between and when the piston rod reaches the vicinity of the stroke end on the rod side, it is throttled by the throttle flow passage to generate a cushioning action by the meter-in. It

[0009]

In the device according to the second aspect of the present invention, the axial position of the oil feed pipe can be adjusted, and the stroke position at which the cushioning action occurs is adjusted by the adjustment.

According to the third aspect of the present invention, when the piston rod reaches the vicinity of the stroke end on the rod side, a cushion action due to meter-out is also generated.

When the fluid pressure cylinder device is a double-acting cylinder, the diameter of the piston is set larger than the diameter of the piston rod. If the cylinder is a single-acting cylinder, it does not necessarily have to do so, so that the same diameter may be used when the cushion action by meter-out is not used.

[0013]

1 is a front view showing a part of a fluid pressure cylinder device 1 according to the present invention in section, and FIG.
6 is a right side view of the mounting portion 32 of FIG. 6, and FIGS. 3 and 4 are simplified front views for explaining the operating principle of the fluid pressure cylinder device 1.

In these figures, a fluid pressure cylinder device 1 includes a cylinder tube 11, a piston 12, a piston rod 13 connected to the piston 12, a head cover 1.
4, a rod cover 15, an oil feed pipe 16 and the like.

The piston 12 slides on the inner peripheral surface of the cylinder tube 11. Piston 12 and piston rod 1
3 is provided with a hole 17, and the oil feed pipe 16 is inserted into the hole 17 as the piston 12 moves.

As shown in particular in FIG. 1, a thick annular connecting member 21, is provided at both ends of the cylinder tube 11.
22 is integrated by welding. These connecting members 2
The cylinder tube 11, the head cover 14, and the rod cover 15 are integrally connected by screwing a plurality of bolts penetrating the head cover 14 and the rod cover 15 into the screw holes provided in the rods 1 and 22. Further, the rod cover 15 is provided with a bolt insertion hole for mounting the entire fluid pressure cylinder device 1.

A port hole 23 is formed in the connecting member 22 on the rod side.
Is provided and the pipe joint 24 is attached thereto by bolts. On the inner peripheral surface near the entrance of the hole 17, in order to form a throttle channel with the plunger 31 described later,
A small-diameter throttle member 41 and a large-diameter throttle member 42 are provided at two locations, one near the inlet and the other far from the inlet.

Referring also to FIG. 2, the oil feed pipe 16 is provided with a plunger 3 provided so as to project into the cylinder chamber CB1.
1. A mounting portion 32 that is connected at the base of the plunger 31 and is fixed to the head cover 14 by a bolt, and one piece for inserting the mounting portion 32 between the mounting portion 32 and the head cover 14 to adjust the axial position of the plunger 31, or It is composed of a plurality of spacers 33. The mounting portion 32 is provided with a port hole 34 which is continuous with the oil feed passage 31b of the plunger 31, and the pipe joint 35 is mounted thereto by a bolt.

On the outer peripheral surface near the tip of the plunger 31, the small-diameter throttle member 41 and the large-diameter throttle member 42 described above are provided.
In order to form a narrowed flow path between and, a small-diameter throttle boss portion 51 and a large-diameter throttle boss portion 52 are provided at two positions, a far side and a near side to the tip. Between the small-diameter throttle boss 51 and the large-diameter throttle boss 52, the oil feed passage 31b and the cylinder chamber C are provided.
A hole 53 communicating with B1 is provided. Further, between the oil feed passage 31b and the cylinder chamber CB1, and between the oil feed passage 31b.
And check chambers CB1b on the front end side of the cylinder chamber CB1 are provided with check valves 54 and 55 that communicate with each other only in opposite directions.

Various packings (not shown) are attached to the respective portions where the sealing is required. Therefore, as shown in FIG. 3, in the contracted state in which the piston 12 and the piston rod 13 enter the cylinder tube 11, the cylinder chamber CB1 can freely flow between the cylinder chamber CB1 and the chamber CB1b on the front end side. It can be seen as the cylinder chamber CB1, and the pressure oil that has flowed out of the oil supply passage 31b through the hole 53 can freely flow into the cylinder chamber CB1.

However, when the piston 12 extends by supplying pressure oil from the port hole 34 and the piston 12 reaches the vicinity of its stroke end as shown in FIG. 4, the small diameter throttle member 41 and the large diameter throttle member 41. 42 approaches or faces the small-diameter throttle boss portion 51 or the large-diameter throttle boss portion 52, respectively, whereby throttle passages are formed at the respective positions, and the pressure oil discharged from the oil feed passage 31b through the hole 53 is discharged. Are squeezed in their respective squeezing channels, and a cushioning action is generated here by meter-in control.

At the same time, a part of the port hole 23 is blocked by the piston 12, and a cushion action by the meter-out control occurs there. That is, two cushion functions of meter-in control and meter-out control occur at the same time.

Therefore, even when the piston 12 and the piston rod 13 are extended and moved at a high speed, the cushioning action of the piston 12 and the piston rod 13 causes sufficient deceleration at the stroke end, and the impact at the time of stopping is sufficiently mitigated.

Further, by supplying the pressure oil from the port hole 23, the piston rod 13 contracts and moves, but at that time, the pressure oil in the cylinder chamber CB1 and the chamber CB1b on the tip end side has the check valves 54 and 55. It can flow through the oil passage 31b as a free flow. Therefore, the movement of the piston rod 13 in the contracting direction is performed without any trouble at the start of the movement.

By adjusting the thickness and the number of spacers 33, the axial position of the plunger 31, that is, the stroke position at which the cushioning action occurs can be adjusted. Therefore, the speed of the piston rod 13,
The most appropriate cushioning action can be obtained according to the load condition and the like.

As described above, according to the fluid pressure cylinder device 1 of the present embodiment, when the piston rod 13 extends and moves, two cushion actions of meter-in control and meter-out control occur simultaneously near the stroke end. Therefore, a sufficient cushioning effect can be obtained.
Therefore, like the injection cylinder, the piston rod 1
Even when 3 is used for an application that operates at an extremely high speed, it is possible to sufficiently absorb the impact at the stroke end and smoothly stop the stroke.

Since the high pressure is not generated by the cushion action by the meter-in control, and the high pressure generated in the meter-out control part can be suppressed to a low level, the strength of each part of the fluid pressure cylinder device 1 is reduced by that much. It is possible to reduce the weight and size of the fluid pressure cylinder device 1, and it is safe.

When used in an injection cylinder,
Usually, a load is applied to the piston rod, which slows down the speed of the piston rod. Therefore, it is possible to omit the meter-out cushion mechanism and absorb the shock only with the meter-in cushion mechanism.

In the above embodiment, the plunger 31
Although one or a plurality of spacers 33 are used as a position adjusting mechanism for adjusting the stroke position of, the stroke position can be continuously changed by, for example, configuring the head cover 14 and the mounting portion 32 to engage with each other by a screw. It is possible to adjust continuously.

In the above embodiment, the small-diameter diaphragm member 4
1, the large-diameter aperture member 42, the small-diameter aperture boss portion 51, and the large-diameter aperture boss portion 52 have a shape protruding in the radial direction from their peripheral portions. A portion between the portion 51 and the root of the plunger 31 is set to have the same height (diameter), and a groove for generating a free flow is formed on the outer peripheral surface or the inner peripheral surface of the portion other than the portion forming the throttle channel. You may keep it. The check valves 54 and 55 may have various known structures.

In addition, the structure, shape, material, number, etc. of each part or the whole of the fluid pressure cylinder device 1 can be appropriately changed in accordance with the gist of the present invention.

[0032]

As described above, according to the present invention, it is possible to obtain a sufficient cushioning action at the stroke end by constructing a cushioning action by meter-in in the head side cylinder chamber.

Therefore, even when the piston rod is used for a high speed operation such as an injection cylinder, it is possible to sufficiently absorb the impact at the stroke end and smoothly stop the stroke.

According to the second aspect of the present invention, the cushioning action can be easily adjusted, and the fluid pressure cylinder device can be adapted to various uses or usage conditions. According to the invention of claim 3 , a further cushioning effect can be obtained, and the invention can be applied to higher speed applications.

[Brief description of drawings]

FIG. 1 is a front view showing a partial cross section of a fluid pressure cylinder device according to the present invention.

FIG. 2 is a right side view of an attachment portion of an oil feed pipe.

FIG. 3 is a simplified front view for explaining the operation principle of the fluid pressure cylinder device.

FIG. 4 is a simplified front view for explaining the operation principle of the fluid pressure cylinder device.

[Explanation of symbols]

1 Fluid pressure cylinder device 11 cylinder tube 12 pistons 13 Piston rod 14 head cover 15 Rod cover 16 Oil pipe 17 holes 33 Spacer 41 Small diameter drawing member (small diameter drawing hole) 42 Large diameter drawing member (large diameter drawing hole) 51 small diameter boss 52 Large diameter boss 53 holes (flow path)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-149604 (JP, A) JP-A-60-184704 (JP, A) JP-A-3-229005 (JP, A) Actual development Sho-58- 135506 (JP, U) Actual development Sho 51-158565 (JP, U) Japanese patent 48-32550 (JP, B1) Japanese patent 48-31185 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F15B 15/22

Claims (3)

(57) [Claims] 1. A cylinder tube, a piston that slides in the cylinder tube, a piston rod that moves integrally with the piston, a head cover that closes the head-side end surface of the cylinder tube, and a rod-side end surface of the cylinder tube. A fluid pressure cylinder device having a rod cover that closes, and an oil feed pipe provided in the head cover so as to project into the cylinder chamber is configured to be inserted into a hole provided in the piston rod and the piston. A metering channel is formed between the inner peripheral surface near the inlet of the hole and the outer peripheral surface near the tip of the oil feed pipe, the throttle channel being provided on the side closer to the inlet of the hole. Small diameter squeezing hole, said hole
Large throttle hole provided on the side far from the inlet of the oil supply pipe
The diameter that is provided on the side close to the tip of the
Provided on the side far from the large throttle boss and the tip of the oil feed pipe
Is formed by a small-diameter boss that fits in the small-diameter throttle hole.
The pressure liquid produced from the oil supply pipe is transferred to the large diameter boss.
From the flow path provided between the small-diameter throttle boss and the hole
It flows within and the piston rod down by the restriction passage when it reaches the vicinity of the stroke end of the rod-side
The fluid pressure cylinder device is configured so that a cushioning action is generated by the meter-in. Wherein adjustable axial position of said oil feed tube, the stroke position of occurrence of the cushioning by adjusting is configured to be adjusted, according to claim 1 Symbol placement of the fluid-pressure cylinder device. Wherein said piston rod is configured to produce cushioning action by the meter-out when it reaches the vicinity of the stroke end of the rod side, the fluid pressure cylinder apparatus according to claim 1 or claim 2, wherein.