JP2001065510A - Hydrostatic pressure cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sufficient cushion action at a stroke end by generating such a cushion action with a meter-in at a head side cylinder chamber. SOLUTION: In a hydraulic cylinder device 1 having a cylinder tube 11, a piston 12, piston rod 13, a head cover 14, and a rod cover 15, wherein a feed- tube 16 provided to the head cover 14 to protrude into a cylinder is inserted in a hole 17 formed in the piston rod 13 and piston 12, a throttle passage with a meter-in is formed between the inner surface around the inlet of the hole 17 and the outer surface around the point of the feed-tube 16 so as to generate a cushion action with the meter-in when the piston rod 13 reaches around the stroke end of the rod side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In general, 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 pressurized oil is often used.

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

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

[0005]

However, as described above, since the piston rod operates at a high speed and the effective pressure receiving area on the rod side is usually set to be small,
The pressure of the pressure oil confined 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 reducing the maximum pressure generated in the cylinder chamber on the rod side. However, in this case, the flow rate of the return pressure oil at the time of the operation of the piston rod increases, so that a load is applied to a filter or the like provided in the return line of the hydraulic unit, which may cause damage.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem, and is configured so that a cushion action by meter-in occurs in a cylinder chamber on a head side, and a fluid pressure capable of obtaining a sufficient cushion action at a stroke end. It is an object to provide a cylinder device.

[0008]

An apparatus according to the present invention comprises 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 for closing the rod side end surface of the cylinder tube, and an oil feed pipe provided in the head cover so as to protrude into the cylinder chamber, in a hole provided in the piston rod and the piston. A fluid pressure cylinder device configured to be inserted, wherein a throttle flow path by meter-in is formed between an inner peripheral surface near an inlet of the hole and an outer peripheral surface near a tip of the oil feed pipe, and the piston When the rod reaches the vicinity of the stroke end on the rod side, the cushioning action by the meter-in occurs. It is.

[0009] In the apparatus according to the second aspect of the present invention, the throttle flow path includes a small-diameter throttle hole provided on a side near the inlet of the hole, and a large-diameter throttle hole provided on a side far from the inlet of the hole. ,
A large-diameter throttle boss provided on the side near the tip of the oil pipe and fitted in the large-diameter throttle hole, and a small-diameter throttle provided on the side near the tip of the oil pipe and fitted in the small-diameter throttle hole A pressure liquid formed by a boss and discharged from the oil supply pipe flows into the hole from a flow path provided between the large-diameter throttle boss and the small-diameter throttle boss, and is throttled by the throttle flow path. It is configured as follows.

In the apparatus according to the third aspect of the present invention, the position of the oil supply pipe in the axial direction can be adjusted, and the adjustment adjusts the stroke position at which the cushion action occurs.

In the apparatus according to the fourth aspect of the present invention, the cushioning action by meter-out is also generated when the piston rod reaches the vicinity of the stroke end on the rod side.

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. In the case of a single-acting cylinder, this is not necessarily the case, so the same diameter may be used when the cushioning effect by meter-out is not used.

[0013]

FIG. 1 is a front view showing a cross section of a part of a fluid pressure cylinder device 1 according to the present invention, and FIG.
3 and FIG. 4 are simplified front views for explaining the operation principle of the hydraulic cylinder device 1.

In these figures, a hydraulic 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 particularly in FIG. 1, thick annular connecting members 21,
22 are integrated by welding. These connecting members 2
A plurality of bolts penetrating the head cover 14 and the rod cover 15 are screwed into the screw holes provided in the first and second 22 to integrally connect the cylinder tube 11, the head cover 14, and the rod cover 15. Further, the rod cover 15 is provided with a bolt insertion hole for mounting the entire hydraulic cylinder device 1.

A port hole 23 is formed in the connecting member 22 on the rod side.
Is provided, and a 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 flow path with a plunger 31 described later,
A small-diameter diaphragm member 41 and a large-diameter diaphragm member 42 are provided at two places, that is, a side near the entrance and a side far from the entrance.

Referring also to FIG. 2, oil feed pipe 16 has a plunger 3 provided to project into cylinder chamber CB1.
1. an attachment portion 32 connected at the root of the plunger 31 and fixed to the head cover 14 by bolts; It consists of a plurality of spacers 33. The mounting portion 32 is provided with a port hole 34 that is continuous with the oil supply passage 31b of the plunger 31, and a pipe joint 35 is mounted to the port hole 34 by a bolt.

On the outer peripheral surface near the tip of the plunger 31, the above-described small-diameter diaphragm member 41 and large-diameter diaphragm member 42 are provided.
In order to form a throttle flow path between them, a small-diameter throttle boss portion 51 and a large-diameter throttle boss portion 52 are provided at two places, a side far from the tip and a side near the tip. Between the small diameter boss portion 51 and the large diameter boss portion 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 supply passage 31b and the cylinder chamber CB1, and between the oil supply passage 31b
Check valves 54 and 55 are provided between the cylinder chamber CB1 and the chamber CB1b on the tip side of the cylinder chamber CB1 so as to communicate only in opposite directions.

Various packings (not shown) are attached to the parts of each part where a seal is required. Therefore, as shown in FIG. 3, in a 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 front end side chamber CB1b, and these are one. The pressure oil which can be regarded as the cylinder chamber CB1 and has come out of the oil supply passage 31b through the hole 53 can freely flow into the cylinder chamber CB1.

However, when the piston 12 is extended by supplying the pressure oil from the port hole 34, and the piston 12 reaches the vicinity of the stroke end as shown in FIG. 42 approach or face the small-diameter boss portion 51 or the large-diameter boss portion 52, respectively, thereby forming a throttle channel at each location. Are throttled in the respective throttle channels, where a cushioning action is generated by meter-in control.

Further, at the same time, a part of the port hole 23 is closed by the piston 12, and a cushioning action by the meter-out control occurs here. That is, two cushion effects of meter-in control and meter-out control occur simultaneously.

Therefore, even when the piston 12 and the piston rod 13 extend and move at a high speed, the cushioning action of the piston 12 and the piston rod 13 sufficiently reduces the speed at the stroke end, so that the shock at the time of stoppage is sufficiently reduced.

The supply of pressurized oil from the port hole 23 causes the piston rod 13 to contract and move. At this time, the pressurized oil in the cylinder chamber CB1 and the chamber CB1b on the distal end side moves the check valves 54 and 55 through the check valves 54 and 55. It can flow through the oil feed passage 31b as a free stream. Therefore, the movement of the piston rod 13 in the contraction direction is performed without any trouble at the start.

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

As described above, according to the fluid pressure cylinder device 1 of the present embodiment, when the piston rod 13 is extended and moved, two cushion effects of meter-in control and meter-out control are simultaneously generated near the stroke end. Therefore, a sufficient cushion effect can be obtained.
Therefore, like an injection cylinder, the piston rod 1
Even when the actuator 3 is used for an operation at an extremely high speed, the impact can be sufficiently absorbed at the stroke end and the operation can be smoothly stopped.

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

When used for an injection cylinder,
Normally, a load is applied to the piston rod, which decelerates the speed of the piston rod. Therefore, the meter-out cushion mechanism can be omitted, and the shock can be absorbed only by 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 adjustment mechanism for adjusting the stroke position, the stroke position can be adjusted steplessly by, for example, configuring the head cover 14 and the mounting portion 32 to be screw-engaged. It is possible to adjust continuously.

In the above embodiment, the small-diameter diaphragm member 4
1. The large-diameter drawing member 42, the small-diameter drawing boss portion 51, and the large-diameter drawing boss portion 52 are formed so as to protrude in the radial direction more than their peripheral portions. A portion between the portion 51 and the root of the plunger 31 is set at 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. Various known structures can be applied to the check valves 54 and 55.

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]

According to the present invention, it is possible to obtain a sufficient cushioning function at the stroke end by forming the cushioning function by meter-in in the cylinder chamber on the head side.

Therefore, even when the piston rod is used for a high-speed operation, such as an injection cylinder, the impact can be sufficiently absorbed at the stroke end and the operation can be smoothly stopped.

According to the third aspect of the present invention, the cushion effect can be easily adjusted, and the fluid pressure cylinder device can be adapted to various uses or use conditions. According to the fourth aspect of the present invention, a further cushioning effect can be obtained, and the present invention can be applied to higher-speed applications.

[Brief description of the drawings]

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

FIG. 2 is a right side view of a mounting portion of the 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]

 DESCRIPTION OF SYMBOLS 1 Fluid pressure cylinder device 11 Cylinder tube 12 Piston 13 Piston rod 14 Head cover 15 Rod cover 16 Oil supply pipe 17 Hole 33 Spacer 41 Small diameter throttle member (Small diameter throttle hole) 42 Large diameter throttle member (Large diameter throttle hole) 51 Small diameter Aperture Boss 52 Large Diameter Aperture Boss 53 Hole (Flow Path)

Claims (4)

[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 a 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 for closing, wherein an oil feed pipe provided in the head cover so as to protrude into the cylinder chamber is inserted into a hole provided in the piston rod and the piston. When a throttle flow path is formed by meter-in between the inner peripheral surface near the inlet of the hole and the outer peripheral surface near the tip of the oil supply pipe, when the piston rod reaches near the rod-side stroke end, A fluid pressure cylinder device, characterized in that a cushion effect by the meter-in is generated. 2. The throttle passage according to claim 1, wherein the throttle passage is provided with a small-diameter throttle hole provided on a side near the inlet of the hole, a large-diameter throttle hole provided on a side far from the inlet of the hole, and near a tip of the oil feed pipe. A large-diameter throttle boss provided on the side of the oil feed pipe and a small-diameter throttle boss provided on the side close to the tip of the oil feed pipe and fitted in the small-diameter throttle hole. The pressure liquid discharged from the oil pipe flows into the hole from a flow path provided between the large-diameter throttle boss and the small-diameter throttle boss, and is throttled by the throttle flow path. Item 2. The hydraulic cylinder device according to Item 1. 3. The fluid pressure according to claim 1, wherein an axial position of the oil feed pipe is adjustable, and a stroke position at which the cushioning action occurs is adjusted by the adjustment. Cylinder device. 4. The hydraulic cylinder device according to claim 1, wherein when the piston rod reaches the vicinity of the stroke end on the rod side, a cushioning action by meter-out also occurs. .