JPH09164286A - Oil feeding device for sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the attenuation effect of oil film and to reduce bearing noises by finishing one end part of helical groove, which is formed between a shaft and bearing, a little inside the other end of bearing and increasing oil film pressure between the shat and the bearing. SOLUTION: An oil feeding hole 27 connected to a supply tube is provided at the upper part of one terminal part on the right side of bearing 24a, and an oil discharge hole 28 connected to a collection tube is provided at the lower part. Besides, a helical groove 26 is formed within the range shorter than the bearing width of a bearing 24a on the peripheral surface of upper shaft 31, and the direction of the helical groove 26 is set so that oil can be supplied from one terminal part 26b of helical groove 26 to another terminal part 26a by revolving the upper shaft 31. The other terminal part 26a of helical groove 26 is finished a little inside the other terminal part on the left side of the bearing 24a, and a ring-shaped groove 29 provided at the position of bearing 24a corresponding to one terminal part 26b of helical groove 26 is connected through an oil supply pipe 63 to the oil supply hole 27. Further, oil seals 25a and 25b are fitted on inner peripheral parts at both the bearing terminals of bearing 24a and, between inside small diameter section of the seals and the bearing part end face of bearing 24a, a small gap is set in axial line direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil supply device for a sewing machine, which reduces vibration and noise generated in the machine frame of the sewing machine during operation of the sewing machine.

[0002]

2. Description of the Related Art A sewing machine generally found in the past has an upper shaft which is supported by a sewing machine frame through a plurality of bearings and which is rotationally driven by a motor, and the needle shaft is rotated by rotating the upper shaft. A moving mechanism such as a balance or a balance is reciprocated or rocked. The inertial force due to the reciprocating motion or the oscillating motion of the motion mechanism becomes a vibrating force for vibrating the sewing machine arm through the bearing of the upper shaft, and vibration and noise are generated in the sewing machine arm and the bed.

Generally, a sliding bearing is better than a rolling bearing for such vibration and noise. This is because the squeeze film effect of the oil film formed on the bearing surface of the bearing acts to damp the vibration. However, this squeeze film effect absorbs vibration by the pressure fluctuation of the oil film, and the amount of oil supply to the bearing must be appropriately large in order to effectively act.

On the other hand, the needle bar and the balance attached to the end of the arm are members that come into direct contact with the sewn product or the thread, and oil must not adhere to them to contaminate them. Not not. Similarly, for the bearing on the arm tip side of the upper shaft, either an unlubricated rolling bearing is used or a very small amount of lubrication is used for the sliding bearing in order to prevent oil stains on the sewing materials and threads. It was

Further, a spiral groove is formed on the upper shaft, and oil is supplied by utilizing the screw pump effect of the spiral groove.
An oil supply device for a sewing machine described in Japanese Utility Model Publication No. 34-11952 is known.

[0006]

However, the squeeze film effect does not work effectively in rolling bearings and sliding bearings with a very small amount of oil. Therefore, in the conventional bearing device of the sewing machine, large vibration and noise are generated, which gives the operator uncomfortable feeling. Further, in the oil supply device for a sewing machine described in Japanese Utility Model Publication No. 34-11952, the spiral groove of the upper shaft is formed up to the end of the bearing so that the oil is supplied to the end of the bearing. Although the amount was large, the oil film pressure did not increase at the end of the bearing, so the noise reduction effect was small.

The present invention has been made to solve the above-mentioned problems, and the other end of the spiral groove formed between the shaft and the bearing is terminated slightly inside the other end of the bearing. ,
An object of the present invention is to provide an oil supply device for a sewing machine in which the oil film pressure between the shaft and the bearing is increased to increase the damping effect of the oil film and reduce the bearing noise.

[0008]

In order to achieve this object, an upper shaft lubrication device for a sewing machine according to claim 1 of the present invention is supported by a machine frame of a sewing machine through a bearing and is rotationally driven by a motor. Which has a shaft formed with a spiral groove for supplying oil between the peripheral surface of the shaft and the inner peripheral surface of the bearing, and in particular, on the one end side of the bearing, One end of the spiral groove is provided and the other end of the spiral groove is terminated slightly inside the other end of the bearing.
Therefore, when the shaft is rotated by the motor, oil is supplied from the one end to the end end side due to the screw pump effect of the spiral groove, and the oil is filmed in the minute gap between the shaft and the bearing. It spreads out evenly and the oil film pressure increases. Therefore, the damping effect of the oil film is increased, and the noise generated from the bearing portion is reduced.

In the oil supply device for a sewing machine according to a second aspect, the oil introduction hole of the spiral groove is communicated with the oil sump.
Therefore, the oil is sequentially supplied from the oil sump each time the sewing machine is operated, the oil is not interrupted, and the oil supply operation can be reliably performed.

In the oil supply device for a sewing machine according to a third aspect of the invention, oil seals are provided at both ends of the bearing. Therefore, oil does not leak from both ends of the bearing, and the thread and the sewn product are not contaminated.

Further, in the oil supply device for a sewing machine according to a fourth aspect of the present invention, oil recovery means for returning the oil passing through the spiral groove to the oil reservoir is provided between the both oil seals. Therefore, the oil used for the lubricating action between the shaft and the bearing is recovered by the oil recovery means and returned to the oil sump,
Used repeatedly for lubrication.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the oil supply device for a sewing machine according to the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, a pair of left and right bearings 24a and 24b mounted inside the sewing machine frame 22 are
The upper shaft 31, which is the shaft of the present invention, is rotatably supported. The upper shaft 31 has a pulley 3 attached to one end thereof.
Rotational power is transmitted from a motor (not shown) via a V-belt 32 attached to 0 and its pulley 30, and is rotationally driven. A balance crank 34 is fixed to the other end of the upper shaft 31, and the balance crank 3
A balance 36 is operably connected to the needle 4, and a needle bar 40 is movably connected to the needle 4 via a needle bar crank 42, a needle bar crank rod 44, and the like. Therefore,
When the balance crank 34 rotates together with the upper shaft 31, the needle bar 40 reciprocates up and down, and the balance 3
6 performs a reciprocating rocking motion.

An oil tank 90 as an oil sump for storing oil is disposed below the upper shaft 31 of the inner lower part of the arm of the sewing machine frame 22. The oil tank 90
And the bearings 24a, 24b are vinyl supply tubes 92a, 92b for supplying oil and vinyl recovery tubes 94a, 9 for collecting oil, respectively.
4b.

FIG. 2 is a view showing details of the inside of the bearing 24a. In the figure, the bearing 24a has an oil supply hole 27 connected to the supply tube 92a at the upper part of the right end thereof, and the recovery tube 94 at the lower part of the same end.
Oil drain holes 28 connected to a are provided respectively.

A spiral groove 26 is formed on the peripheral surface of the upper shaft 31 within a range shorter than the bearing width of the bearing 24a. The direction of the spiral groove 26 is the same as that of the upper shaft 31. By rotation, one end 26b of the spiral groove 26 to the other end 26a
The oil is set to be supplied (from right to left in the figure). The other end 26a of the spiral groove 26 terminates slightly inside the other end on the left side of the bearing 24a, as is apparent from FIG.

One end 26 of the spiral groove 26 of the bearing 24a
A ring-shaped groove 29 is provided at a position corresponding to b,
The ring-shaped groove 29 and the oil supply hole 27 are connected by an oil supply pipe 63. Oil seals 25a and 25b are attached to the inner peripheral portions of both ends of the bearing 24a, and the inner small diameter portion of each oil seal 25a and 25b and the bearing 24 are attached.
A slight gap is set in the axial direction between the end surface a of the bearing a and the flow of the used oil for recovery is improved. The lip portions of the oil seals 25a and 25b are formed of nitrile butadiene rubber (NBR) having excellent oil resistance, and are in contact with the outer peripheral surface of the upper shaft 31. In particular, in the oil seal 25a, the lip portion is pressed against the outer peripheral surface of the upper shaft 31 by the elastic force of the coil spring 33 to reliably prevent oil leakage to the balance crank 34 and the needle bar 40 side. The oil seal 25b on the right side is used for the balance crank 34 and the needle bar 40.
Since the thread and the sewn product are not directly contaminated even if some oil leakage occurs, the one having a slightly low sealing property and a small sliding resistance is attached.

Further, the spiral groove 26 is provided between the oil seals 25a and 25b inside the lower side of the bearing 24a.
An oil discharge pipe 64 is provided as an oil recovery means for recovering the oil used for lubrication. The oil drain pipe 64 is connected to the oil drain hole 28.

On the other hand, with respect to the internal structure of the right bearing 24b, the spiral grooves are formed not at the upper shaft 31 but at the inner peripheral surface of the bearing 24b at the same pitch, as opposed to the left bearing 24a. The rest of the structure is exactly the same as that of the left bearing 24a, and the description thereof is omitted.

Next, referring to FIG. 2, the operation according to the present embodiment configured as described above will be described with reference to FIG.
a will be described.

When the upper shaft 31 is rotationally driven by a motor, the upper shaft 31 rotates in the direction of the arrow in FIG. 2, and the screw pump effect of the spiral groove 26 formed in the upper shaft 31 causes an oil tank 90. The oil is sucked from and is supplied to the bearing 24a via the supply tube 92a. The oil supplied to the bearing 24 a is supplied from the oil supply hole 27 to the oil supply pipe 63.
And is supplied to the ring-shaped groove 29 via. Since the ring-shaped groove 29 is connected to the one end portion 26b of the spiral groove 26, the oil supplied to the ring-shaped groove 29 is
Regardless of the rotation angle of the upper shaft 31, it is always supplied to the spiral groove 26 and spreads on the inner peripheral surface of the bearing 24a, and most of it is transferred from the other end 26a of the spiral groove 26 to the needle bar side end of the bearing 24a. And is guided to the oil drain hole 28 through the oil drain pipe 64. The oil discharged from the oil drain hole 28 is returned to the oil tank 90 via the recovery tube 94a.

By the rotational driving of the upper shaft 31, oil is supplied in proportion to the number of rotations thereof. Therefore, during the operation of the sewing machine, a proper amount of oil is constantly supplied to the bearing 24a, and an oil film is formed on the bearing surface. In particular, since the spiral groove 26 is not formed in the upper shaft 31 on the left side portion of the bearing 24a,
The oil film pressure increases due to the oil passing through the minute gap between the upper shaft 31 and the bearing 24a, and the oil film damping effect increases.

On the other hand, in the bearing 24b on the right side, the oil tank 90 is exactly the same as the bearing 24a on the left side.
Oil is supplied from the supply tube 92b and returned from the recovery tube 94b to the oil tank 90, and during this time, the lubricating action of the upper shaft 31 is performed in exactly the same manner.

The present invention is not limited to the one shown in the above-mentioned embodiment, but various modifications can be made without departing from the scope of the invention.

For example, although the spiral groove is formed on the upper shaft or the bearing in this embodiment, the spiral groove is formed in cooperation with both the outer peripheral surface of the upper shaft and the inner peripheral surface of the bearing. May be. Further, although the upper shaft is taken up as the shaft to be refueled, the lower shaft for driving the shuttle is not limited to the upper shaft,
Alternatively, the oil supply device of the present invention can be applied to various shafts used in addition to the above. Further, although the oil supply hole and the oil discharge hole of the bearing are provided in the upper portion and the lower portion of the bearing end surface in the present embodiment, they may be provided in other portions.
Furthermore, since oil leakage does not cause much problem except for oil leakage to the needle bar side end of the sewing machine arm tip side bearing, an oil seal may be used only there. As a result, the sliding resistance of the upper shaft 31 is reduced, and a drive motor with low power can be used.

[0026]

As is apparent from the above description,
According to the oil supply device for a sewing machine according to claim 1 of the present invention,
A sewing machine frame has a shaft supported by a bearing and driven to rotate by a motor, and a spiral groove for supplying oil is formed between a peripheral surface of the shaft and an inner peripheral surface of the bearing. In particular, since the one end of the spiral groove is provided on the one end side of the bearing and the other end of the spiral groove is terminated slightly inside the other end of the bearing,
When the shaft is rotated by a motor, oil is supplied from the one end to the end end side by the screw pump effect of the spiral groove, and the oil forms a film in the minute gap between the shaft and the bearing. It spreads evenly and the oil film pressure can be increased. For this reason, the damping effect of the oil film is increased, and the noise generated from the bearing portion can be reduced.

Further, according to the oil supply device for a sewing machine of the second aspect, since the oil introduction hole of the spiral groove is communicated with the oil sump, oil is sequentially supplied from the oil sump every time the sewing machine is operated. Therefore, the oil will not be interrupted, and the refueling action can be surely performed at any time.

According to the oil supply device for a sewing machine of the third aspect, since oil seals are provided at both ends of the bearing, oil leakage does not occur from both ends of the bearing. Does not stain threads or sewn items.

Further, according to the oil supply device for a sewing machine of the fourth aspect, oil recovery means for returning the oil passing through the spiral groove to the oil sump is provided between the both oil seals. The oil used for lubrication between the shaft and the bearing is
It can be recovered by the oil recovery means and returned to the oil sump for repeated lubrication.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an oil supply device for a sewing machine of the present embodiment.

FIG. 2 is a sectional view of a main part of a bearing portion of the oil supply device for a sewing machine according to the present embodiment.

[Explanation of symbols]

 22 sewing machine frame 24a, 24b bearings 25a, 25b oil seal 26 spiral groove 26a other end 26b one end 31 upper shaft 64 oil drain pipe 90 oil tank

Claims (4)

[Claims] 1. A sewing machine frame having a shaft supported by a bearing and rotationally driven by a motor, for supplying oil between a peripheral surface of the shaft and an inner peripheral surface of the bearing. In the oil supply device of the sewing machine having the spiral groove formed, the one end of the spiral groove is provided on one end side of the bearing, and the other end of the spiral groove is terminated slightly inside the other end of the bearing. Refueling device for sewing machines. 2. The oil supply device for a sewing machine according to claim 1, wherein one end of the spiral groove is communicated with an oil sump. 3. The oil supply device for a sewing machine according to claim 1, wherein oil seals are provided at both ends of the bearing. 4. The oil supply device for a sewing machine according to claim 3, wherein an oil recovery means for returning the oil passing through the spiral groove to the oil reservoir is provided between the both oil seals.