JPS61271103A - Ball caster - Google Patents

Abstract

PURPOSE:To make it possible to always form a sufficient oil film on the outer surface of a ball, by attaching an outer cylinder slidably to a receiving bed, and by forming an oil chamber among the receiving bed, the outer cylinder and a ball receiver with the oil chamber being communicated with the spherical surface of the ball receiver through an oil feed port. CONSTITUTION:Oil is filled in an oil chamber 9 and an air vent hole 10 by being charged from a hydraulic unit fitted into a connector 13 through a hole 12, after removal of a plug 11, to engage an outer cylinder 5 with a stopper 8, and thereafter, the plug 11 is reinstalled. In this condition, when a load is exerted to a ball 2, a force effected in the oil chamber 9 is in such a condition that the force acting upon the oil from the ball 2 through a ball receiver 1 balances with its reaction force. Further, the oil in the oil chamber 9 is always fed to the spherical surface 3 of the ball receiver 1 through an oil feed port 4. If the volume of oil in the oil chamber 9 is reduced, being consumed as an oil film on the ball 2, due to use for a long period, the outer cylinder 5 and the ball receiver 1 descend when any load is exerted to the ball 2. Accordingly, it is possible to always continue the supply of oil from the oil chamber 9.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ball caster, and in particular to a ball caster that is capable of forming a sufficient oil film on the surface of the ball without constantly supplying oil from the outside, and that allows the ball to remain stable even under high loads. Regarding ball casters that can rotate smoothly.

[Prior art and its problems] Conventionally, in Japanese Utility Model Publication No. 39-1152, a ball receiver having a spherical cutout surface capable of supporting the ball from below is provided on a pedestal, and the ball receiver is A ball caster is described in which a ball is mounted and an outer cylinder for holding the shoulder of the ball is screwed into the ball receiver.

However, this ball caster requires some kind of oil supply means to supply oil to the oil supply port provided in the ball receiver. Therefore, the ball caster itself becomes an oversized piece of equipment, and there is also a drawback that the service cost increases because a predetermined amount is constantly supplied from the outside. Furthermore, if the means for supplying oil from the outside breaks down and a failure occurs such that a predetermined amount of oil cannot be supplied, an oil film cannot be formed and the ball cannot rotate smoothly.

Therefore, the present invention makes it possible to form a sufficient oil film on the surface of the ball without constantly supplying oil from the outside as in the past, and to ensure smooth rotation of the ball even when a high load is applied. The technical challenge is to provide a ball caster that can.

[Means for Solving the Problem] A ball caster of the present invention that solves the above technical problem has a spherical surface on a pedestal that can rotatably support a ball from below, and the spherical surface is oil-filled. It has a ball receiver in which an oil supply port is drilled, and the ball is placed on the ball receiver,
In a ball caster in which an outer cylinder that holds the shoulder of the ball is screwed to the ball receiver, the outer cylinder is slidably fitted to the holder, and the holder, the outer cylinder, and the ball receiver An oil chamber is formed between the oil chamber and the spherical surface, and the oil chamber and the spherical surface are electrically connected through an oil supply port.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view showing an oil reservoir formed on a spherical surface of a ball receiver.

In FIG. 1, l is t whose upper surface supports the ball 2 from below.
The ball receiver 1 has a spherical surface 3, and an oil supply port 4 for supplying oil to the spherical surface 3 is bored approximately in the center of the ball receiver 1.

Reference numeral 5 denotes an outer cylinder for holding the shoulder portion of the ball 2 on which the ball 2 is placed on the ball receiver 1, and is screwed onto the outer surface of the ball receiver 1. The outer cylinder 5 is slidably fitted onto the pedestal 6. That is, for example, the outer cylinder 5 is inserted into the inner side of the outer frame 7 constituting the pedestal 6, and then stopped by a stopper 8, and is slidably fitted into the outer frame 7. The stopper 8 is connected to the oil chamber 9
This member regulates the maximum amount of oil in the oil chamber 9, and is configured to prevent the outer cylinder 5 from rising any further when the oil chamber 9 is filled with oil.

On the other hand, when the amount of oil is low, the pedestal 6 moves to the ball 2.
It functions as a stopper that regulates the minimum allowable amount of oil that can be supplied at all times. That is, the amount of oil in the oil chamber 9 gradually decreases, and the outer cylinder 5 and the ball receiver 1 also descend accordingly.

It is configured so that it finally hits the pedestal 6.

Reference numeral 9 denotes an oil chamber, which consists of a space surrounded by a pedestal 6 on the lower side, an outer frame 7 constituting the pedestal 6 on the side, and an outer cylinder 5 and a ball holder l on the upper side. The core oil chamber 9 and the spherical surface 3 are connected to the oil supply port 4
Conducted through.

An air vent hole 10 is bored in the pedestal 6 below the oil chamber 9,
A blind stopper 11 is attached to it. Above oil chamber 9
is a high-pressure container with the blind stopper 11 attached. For example, with the blind stopper 11 removed, a high-pressure container that can apply high hydraulic pressure to the oil chamber 9 using general hydraulic equipment. It is. And the air vent hole 1 of the blank plug 11
0 screwing force is also designed to withstand the above-mentioned high pressure.

In this embodiment, when oil is supplied to the oil chamber 9 in advance, there is a hole 2 in the pedestal 6 leading to the oil chamber 9, and a connector 13 (with a check valve) for communicating hydraulic equipment, etc. to the chain hole 12. Although it is preferable to provide oil so that oil can be supplied from outside the ball caster l, it is also possible to supply oil from the air vent lO without providing this.

In this embodiment, it is preferable that the spherical surface 3 of the ball receiver l in contact with the ball 2 is provided with a radially grooved oil reservoir 14 as shown in FIG. Therefore, it goes without saying that the shape of the oil reservoir 14 is not limited to a radial shape. The oil reservoir 14 communicates with the oil supply port 4 so that oil can be supplied from the oil chamber 9.

Note that an adhesive layer with a release paper, a rubber plate, or the like may be provided on the lower surface of the pedestal 6, if necessary, or the lower surface may be formed into an arbitrary non-slip shape such as a corrugated shape.

The usage of the above embodiment is described below.

First, the ball caster is placed upside down as shown in FIG. 1, the blank stopper 11 is removed, and oil is filled from the hydraulic equipment attached to the connector 13 through the hole 12 to the oil chamber 9 and air vent hole 10. In this case, it is important to put enough oil into the oil chamber 9 so that the outer cylinder 5 engages with the stopper 8. Also, care must be taken to prevent air from getting into the oil chamber 9, since letting compressible air mix in will not work well for backing up the ball. When it is filled with oil, screw on the blind stopper 11 and tighten the blind stopper it with a screwdriver or the like to make it blank.

When a load is applied to the ball 2 filled with oil as described above, the force acting in the oil chamber 9 is the force exerted from the ball 2 on the oil via the ball receiver 1, and the reaction force. It is in a state of balance. That is, since the compressibility of the oil in the oil chamber 9 can be ignored, the force applied to the oil directly acts as a reaction from the internal pressure.

The oil in the oil chamber 9 is constantly supplied from the oil supply port 4 to the spherical surface 3 of the ball receiver 1, and over a long period of use, the oil in the oil chamber 9 may increase, for example, as the ball 2 rotates. When the oil film gradually decreases, when a load is applied to the ball 2, the outer cylinder 5 and the ball receiver 1 move downward in the drawing. Therefore,
Even if the amount of oil decreases, there is no need to supply oil from the outside, and the oil in the oil chamber continues to be supplied at all times, so the ball can always rotate smoothly even when a high load is applied.

[Effect J] According to the present invention, it is possible to form a sufficient oil film on the surface of the ball without constantly supplying oil from the outside as in the conventional case, and the ball always rotates smoothly even when a high load is applied. It can be done.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view showing an oil reservoir formed on a spherical surface of a ball receiver. In the figure, l is a ball receiver, 2 is a ball, 3 is a spherical surface, 4 is an oil supply port, 5 is an outer cylinder, 6 is a pedestal, and 9 is an oil chamber.

Claims (2)

[Claims] (1) A ball receiver having a spherical surface that can rotatably support the ball from below and having an oil supply port for supplying oil to the spherical surface is provided on the pedestal, and the ball receiver In a ball caster in which a ball is placed on a ball, and an outer cylinder that holds the shoulder of the ball is screwed to the ball receiver, the outer cylinder is slidably fitted to the holder, and the holder and the outer cylinder are screwed together. A ball caster characterized in that an oil chamber is formed between the tube and the ball receiver, and the oil chamber and the spherical surface are electrically connected through an oil supply port. (2) A radially grooved oil reservoir is provided on the spherical surface of the ball receiver that contacts the ball, and the oil reservoir and the oil chamber are electrically connected through an oil supply port. A ball caster according to claim 1.