JPH0596502U - Piston type accumulator - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention provides a piston with a small-diameter bearing mounting part, and by mounting a linear rotary bearing on this part, the rolling element holds the clearance of the cylinder piston. The weight of the piston is not added to the seal member and the seal member is protected from wear due to wear. [Structure] A cylinder is fitted with a piston having a sliding portion and a bearing mounting portion having a diameter smaller than that of the piston, an annular groove is provided in the sliding portion of the piston, and a sealing member is inserted thereinto to mount the bearing. A plurality of oblong circulation grooves are provided in the retainer in the gap between the cylinder and the cylinder, and a linear rotary bearing in which rolling elements are arranged in rows is inserted in these circulation grooves. And the load is applied to the rolling element and not to the seal member.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a piston type accumulator. Specifically, a piston is equipped with a small-diameter bearing mounting part, and a linear rotary bearing is mounted in this part, and the rolling element holds the gap between the cylinder and piston so that the seal load does not bear the piston load. Type accumulators.

[0002]

[Prior Art]

 Conventionally, in order to prevent a phenomenon in which a piston fitted in a cylinder receives a lateral load to cause galling of the cylinder, a piston provided with a seal member and a wear ring is disclosed in Japanese Patent Application No. 54-95240 and No. Japanese Patent Application No. 58-107784 has a microfilm of Japanese Patent Application No. Sho 54-88184, and a microfilm of Japanese Patent Application No. 58-107784, which reduces sliding resistance by installing a linear bush between the cylinder rod and the rod cap. Furthermore, linear rotary bearings that are mounted between the sliding shaft and the bearing tube to reduce the sliding resistance of the shaft are disclosed in JP-B-40-12564, JP-B-37-23909, and JP-B-47-19416. It is known from each of the publications.

However, in the cylinder using the wear ring described above, since the wear ring has elasticity to perform a damper action, the cylinder is crushed when the weight of the piston is applied and the weight of the piston is negatively applied to the seal member. The seal member not only wears due to strong friction with the cylinder, but also the piston has a large resistance to movement.In addition, for cylinders with a linear bush attached to the rod, the rod bends due to the piston weight and the seal member Since it is impossible to prevent friction with the roller, this also causes wear of the seal member, and the piston has a large resistance to movement. Furthermore, the known linear bearing mounted between the sliding shaft and the bearing has its rolling element It only makes rolling contact with the shaft and bearing to reduce sliding resistance, and it is combined with the seal member between the shaft and bearing. In addition, it does not have the function of preventing the weight of the piston from being added to this seal member.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of this situation.By providing a sliding portion and a bearing mounting portion having a smaller diameter than that on the piston, a known linear bearing is inserted between the piston and the rolling element, and An object of the present invention is to provide a piston-type accumulator that maintains the distance between the cylinder and the piston so that the piston load is not applied to the seal member and protects the seal member from wear due to uneven wear.

[0005]

[Means for Solving the Problems]

 According to the present invention, a piston having a sliding portion and a bearing mounting portion having a diameter smaller than that of the piston is fitted into a cylinder, an annular groove is provided in the sliding portion of the piston, and a sealing member is inserted. In the gap between the bearing mounting part and the cylinder, a cage is provided with a plurality of oblong circulation grooves, and linear roller bearings containing rolling elements are installed in these annular grooves. The problem is solved by a structure in which a gap is maintained between a cylinder and a piston, and the load of the piston is loaded on the rolling element and not the sealing member.

[0006]

[Action]

 In the piston type accumulator with the above-mentioned configuration, a well-known seal member is inserted in the annular groove provided in the cylinder sliding part of the piston, and the elliptical circulation groove is formed in the piston mounting part formed with a diameter smaller than the sliding part. If a plurality of cages are provided, and the cages in which the rolling elements are housed are installed in the annular grooves, respectively, and the pistons are fitted into the cylinders, a known linear rotary bearing is constructed between the pistons and the cylinders. The rolling element makes rolling contact with both the piston and the cylinder to maintain the distance between them, so that even if the weight of the piston is large, the weight of the piston is not added to the above-mentioned sealing member and therefore the seal is not applied. Since the member causes only a slight friction on contact with the cylinder due to the seal pressure, uneven wear of the seal member is significantly reduced.

Further, since the rolling element of the linear rotary bearing described above makes rolling contact with the piston and the cylinder, the resistance against the movement of the piston becomes slight, and the piston operation is performed very efficiently.

[0008]

【Example】

 An embodiment of a piston type accumulator according to the present invention will be described below with reference to the drawings.

FIG. 1 is a partial vertical sectional side view showing an embodiment of a piston type accumulator according to the present invention. FIG. 2 is a vertical sectional front view of a part of the above. FIG. 3 is a partial plan view showing the structure of the linear rotary bearing used in the above. FIG. 4 is a side view showing the whole of the above-mentioned accumulator.

In FIG. 1, reference numeral 1 denotes a cylinder for an accumulator for accumulating and buffering a pressure liquid. As shown in FIG. 4, a piston 2 is fitted inside the cylinder, and a gas chamber 3a on one side and a gas chamber 3a on the other side are provided. The liquid chamber 3b is partitioned, a gas sealing valve 4 is attached to the outer end of the gas chamber 3a, and a liquid inlet / outlet 5 is provided at the outer end of the liquid chamber 3b. As shown in FIG. 1, there are provided a sliding portion 2a for the cylinder 1 and a bearing mounting portion 2b formed to have a diameter smaller than that of the sliding portion 2a by the diameter of the rolling element, which will be described later.

The positional relationship between the sliding portion 2a and the bearing mounting portion 2b is not limited to that in the above embodiment, but can be appropriately changed according to the size of the piston 2, operating conditions, and the like. ..

Reference numeral 6 denotes an annular groove provided around the sliding portion 2a of the piston 2 as shown in FIG. 1, and is made of a material such as rubber and has a seal member 7 that comes into contact with the cylinder 1 by elasticity, and this seal. A back-up ring 8 for preventing the seal member 7 from protruding is fitted to one side or both sides of the member 7.

LB is a linear rotary bearing mounted on the outer circumference of the piston 2 as shown in FIGS. 1 and 2. The cage 9 is provided with a plurality of oblong circulation grooves 10 and the circulation grooves 10 have rigidity. The rolling elements 11 are housed in a row and are fitted into the bearing mounting portion 2b of the piston 2, and the outside of the rolling element 11 is held by the holding ring 12 screwed into the piston 2 to be supported by the piston 2. When the piston 2 is fitted into the cylinder 1, it is mounted between the piston 2 and the cylinder 1, and its rolling element 11 makes rolling contact with the piston 2 and the cylinder 1 to maintain the space between the piston 2 and the cylinder 1. Let Ston 2 move smoothly and lightly.

When the rolling element 11 of the linear rotary bearing LB makes a circulating motion in the circulation groove 10 shown in FIG. 2, the rolling element 11 on the load range L side comes into contact with both the cylinder 1 and the piston 2 and has a space. It is desirable that the one that has a holding function but is on the non-load range L'side contacts the cylinder 1 or the piston 2 and does not contact the other and does not receive its weight. As shown in FIG. 2, a concave portion 13 is provided in a portion corresponding to the load range L to satisfy this condition.

In the device shown in the above embodiment, when the cylinder 1 is used laterally or obliquely, the rolling element 11 of the linear rotary bearing LB is in contact with both the cylinder 1 and the piston 2 to maintain the space, and the piston 2 The load between the seal member 7 and the cylinder 1 is not carried by the seal member 7, and the friction between the seal member 7 and the cylinder 1 is small, and even if the piston 2 is moved frequently, the seal member 7 is almost completely worn. Since it does not wear, even if a general accumulator causes a decrease in the filled gas pressure in a short time due to the worn-down seal member, it is possible to maintain the specified filled gas pressure for a long time. It was proved that the durability of the material 7 was improved 10 times or more.

[0016]

[Effect of the device]

 As described above, in the piston type accumulator according to the present invention, the rolling element of the linear rotary bearing holds the distance between the piston and the cylinder to bear the load of the piston and not the seal member. Since it only rubs against the cylinder with the seal pressure and hardly wears evenly, the durability of the seal member is more than 10 times higher than that of general accumulators, while the cylinder keeps the specified filled gas pressure. Therefore, it greatly contributes to improvement of accumulator operation rate and reduction of maintenance cost.

The rolling element of the linear rotary bearing is in rolling contact with the piston and the cylinder to smoothly and smoothly move the piston while maintaining the distance between the rolling element and the piston, which is particularly effective in improving the operating performance of the accumulator. It is what is done.

[Brief description of drawings]

FIG. 1 is a partial vertical sectional side view showing an embodiment of a piston type accumulator according to the present invention.

FIG. 2 is a vertical sectional front view of a part of the above.

FIG. 3 is a plan view of a part of the linear rotary bearing used in the above.

FIG. 4 is a side view showing the whole of the above accumulator.

[Explanation of symbols]

 1 Cylinder 2 Piston 2a Sliding part 2b Bearing mounting part 6 Annular groove 7 Sealing member 9 Cage 10 Circulation groove 11 Rolling element LB Linear rotary bearing

Claims (1)

[Scope of utility model registration request] 1. A piston having a sliding portion and a bearing mounting portion having a diameter smaller than that of the piston is fitted into a cylinder, an annular groove is provided in the sliding portion of the piston, and a sealing member is inserted into the cylinder. In the gap between the bearing mounting part and the cylinder, a cage is provided with a plurality of oblong circulation grooves, and linear roller bearings accommodating rolling elements are installed in these annular grooves. The piston type accumulator is characterized in that a gap is maintained between the piston and the piston so that the load of the piston is loaded on the rolling element and not the sealing member.