JPS5930933B2 - Datsushi pot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semi-rotary type damper or dashpot which provides a damping effect by the movement Q of liquid within a chamber by a rotatable vane rotor.

When this type of dashpot is subjected to a torque that rotates the rotor relative to the chamber, the resistance to fluid movement provides a damping effect, but the fluid pressure in the chamber acting on one side of each vane increases. and the pressure acting on the opposite side decreases.

If a significant pressure drop occurs due to the action of a large torque, voids will form in the liquid.

When the suction force ceases to act, the voids disappear, but it cannot be expected that the liquid will completely return to its original state.

This is because the voids will contain gas that has already been dissolved in the liquid.

Even when gas is removed from the liquid by pre-vacuum treatment, it is very difficult or impossible to avoid the formation of bubbles.

Complete removal of dissolved gases, such as air, is not possible under industrial conditions, and gases can also be generated in the liquid from other sources, such as from outgassing on the inner surfaces of dashpots.

The presence of air bubbles in the dashpot liquid has a significant effect on the operation of the dashpot.

In particular, a rattling vibrational movement (jerky movement) occurs, and if the movement of the dashpot is a return stroke, a backlash will occur.

The creation of a void means that liquid has been displaced from the dashpot chamber.

In particular, it is known to provide a reservoir region that can compensate for differences in thermal expansion coefficients.

This reservoir area is capable of receiving the volume of liquid transferred as expressed by the volume of the void, from which liquid returns to the chamber of the dashpot when the void is filled.

However, since this reservoir is intended to compensate for fairly slow volume changes, and the damping effect is provided by pressure changes caused by the movement of the dashpot rotor, it is difficult to Only very limited communication paths are provided with the reservoir.

Therefore, the reservoir is unable to respond to instantaneous pressure changes, and the maximum suction pressure, which is the cause of void formation, is not affected by the presence of the reservoir.

Therefore, it is an object of the present invention to eliminate the problems described above when high torques are applied.

The invention includes filling a chamber within the housing with a liquid;
A rotor having at least one vane is rotatably disposed in the chamber and configured to provide a damping effect by forced fluid flow between opposite sides of the vane, and a hollow boss is disposed on the rotor to provide a fluid reservoir. a semi-rotary device configured to define a functional interior space and provide fluid communication within the rotor to permit substantially unrestrained fluid flow from the reservoir through the rotor to a pressure reduction region of the chamber; type dashpot, a flexible sealing sleeve is provided between the bousing and the vane, at least a portion of the sealing sleeve extending into the boss of the rotor, and the sealing sleeve extending within the radially inner wall of the reservoir. The structure is such that it forms a .

According to such a structure, it is possible to prevent or limit the generation of suction pressure of an undesirable magnitude, and also to prevent the generation of high pressure peaks during dashpot operation, thereby ensuring an appropriate buffer response.

This makes it possible to avoid the above-mentioned problems caused by the effects of high torque.

In such a construction, the sealing sleeve performs a dual function.

One seals the interior space of the dashpot without the use of sliding piston seals that are prone to wear and leakage.

The other is to quickly respond to fluid pressure drops to prevent voids from forming.

In one embodiment of the invention, the communication mechanism includes a valve-controlled passageway, which passageway is configured to open when a predetermined pressure drop relative to ambient pressure occurs in the chamber region.

This is particularly suitable for double-acting dashpots.

In this case, the vanes of the rotor dividing the individual chamber regions can be provided with a communication mechanism with oppositely directed valves controlling the flow from the reservoir to the chamber regions via a common conduit, and both valves Each can be biased in opposite directions to the normally open position by springs.

In another embodiment of the invention, in the case of a single-acting dashpot, the vanes of the rotor are provided with a communication mechanism having passages communicating between the opposite sides of the vane, allowing interconnection of the chamber areas on both sides of the vane. to obtain free movement in the direction of return.

The passageway is also connected to a reservoir, and a valve is provided in the passageway.

The position of the valve is such that it can prevent flow from the high pressure side of the vane to the reservoir during movement of the rotor in the working direction.

In a preferred embodiment, the fluid communication mechanism within the rotor has at least one passageway opening directly into the reservoir opposite the sealing sleeve.

In addition, when the rotor is a die-cast component having a plurality of vanes, the communication mechanism can be provided with a slot-shaped passage communicating from each vane to the hollow boss.

These passages can be easily obtained by forming grooves with both ends open during die-casting of the rotor, and closing the ends of these grooves by inserting filling members.

Hereinafter, the present invention will be described in detail based on embodiments with reference to the accompanying drawings.

The dashpot shown in FIGS. 1 and 2 is of the double-acting type and has a hollow casing 2 consisting of two parts.

In the casing 2 a rotor 4 is fixed by splines 12 to a shaft 10 which is supported by bearings 6 and 8.

The rotor 4 has a hollow circular boss 14.

This boss is fitted into the casing close to the inner arcuate surface of a fastening part 16 and together with the fastening part forms two diametrically opposed sector-shaped chambers 18 .

The vanes 20 of the rotor can be angularly displaced within each chamber 18 as the rotor rotates.

A buffer liquid is filled into the casing through a filling hole closed by a screw 22, and this liquid is introduced into the casing by the 0-IJ song 4 between the two die-cast casing parts;
It is sealed by a torsionally flexible sealing sleeve 26.

The sealing sleeve is connected and fixed at one end to a hollow plug 30 of the casing by a first catch 28 and at its other end to the shaft 10 on which the rotor 4 is fixed by a second catch 32. And it is fixed.

In use, a small gap 34 (best shown in FIG. 2) between the edge of each vane and the chamber wall adjacent to the vane edge allows each vane to be closed as the rotor rotates within the casing. Limited fluid flow between regions on either side of the vane is allowed.

This resistance to liquid movement provides a damping effect.

It is clear that a change in temperature results in a relative change in the volumes of the chamber and the liquid, so that the annular space 36 between the rotor hollow boss 14 and the flexible sleeve 26
(Ambient pressure or atmospheric pressure naturally acts on the inside of the flexible sleeve via the bearing 8)
.

This space 36 serves as a variable volume reservoir to adjust volume changes of the liquid.

Although the sleeve is shown at its maximum displacement against the backing ring 38 over its entire length, at relatively low temperatures the sleeve is elastically deformed by atmospheric pressure and separates from the backing ring 38. Some liquid then escapes from the gap 40 between the casing end wall and the rotor top into the space 36 due to thermal expansion of the liquid relative to the chamber volume.

However, the path through the gap 40 to the space 36 is naturally very limited so that the damping function provided by the movement of the vanes is not reduced.

It therefore has little or no effect on the instantaneous changes that occur in the chambers when large torques are applied to the rotor, and therefore there is little or no effect on the expanding space behind the vanes in the individual chambers. A severe pressure drop will occur.

As previously discussed, this creates voids in the liquid, resulting in bubbles in the liquid within the chamber, with attendant performance degradation of the dashpot.

This drawback, in the illustrated construction, allows for free flow from the inner annular space into the expansion space in the event of a pressure drop in the expansion space behind the trailing surface of each rotating individual vane. It can be solved by

For this purpose, each vane has a passageway 4 communicating between its opposite sides.
4 is formed, and a slot-shaped hole 46 connects the annular space 36 to the passage 44 via the boss.

Further, backflow prevention valves 48 are provided in the passage 44 on both sides of the hole 46, respectively.

The valve in each vane has a pair of opposed frusto-conical valve discs, each having a spring 52.
is pressed against the valve seat 50 in the vicinity of the hole 46.

These two springs 52 are attached in compression to a common coupling member 54.

The coupling member passes through the spring and the valve body, and has two flaps 5 at both ends.
6, against which the outer end of the spring rests.

That is, the valve body is pressed firmly against the valve seat by the spring force and positive fluid pressure to prevent any flow from the high pressure region on either side of the vane into the inner annular space 36.

However, when a negative pressure develops in the associated chamber area, the valve body lifts against the elastic force of the springs, allowing free flow of fluid from the annular space 36 into the relevant chamber area.

This prevents the formation of voids and the resulting formation of air bubbles.

The test confirmed that there was no formation of bubbles caused by the separation of gases already dissolved in the buffer liquid.

Therefore, it is no longer necessary to degas the liquid before use, which is essential in the conventional dashpot structure, contributing to cost reduction.

Additionally, tests have shown that even if some air is mixed in in the form of bubbles at the beginning, in the dashpot with the structure shown, the bubbles tend to dissolve into the liquid and have little or no effect. .

The slot-shaped holes 46 between the annular space 36 and each valve passage 44 have a sufficiently large cross-sectional area to prevent flow restriction, allowing flow to flow through the relatively large valve passages.

If die-cast or cast, these slots and passageways 44 can conveniently be formed integrally with the main body of the rotor, provided that they are allowed to open into one end of the rotor and into the boss.

The hole at the end of the rotor body of the slot is closed with an auxiliary stuffing member 62.

The padding member has an inner circular ring 64 and integral diametrically opposed arms 66 which fit snugly into complementary grooves in the end of the rotor body.

The stuffing member 62 itself can also be made by die casting or casting.

The embodiment shown in FIGS. 3 to 5 is a single-acting dashpot that provides a damping function only in one direction of rotation.

This dashpot has the same basic structure as shown in FIGS. 1 and 2, except for the rotor 70 and associated valves.

The rotor 70 shown in FIGS. 3 to 5 also has a hollow boss 72 similar to that of the first embodiment shown in FIGS. 1 and 2.
It also has similar splines 74 for securing the rotor to the rotor shaft and a padding member 76 that fits into the die-cast body.

In this example, since the torque acts in only one direction, and only one side 78 of each vane is subjected to the low pressure, the chamber space associated with it is in free communication with the inner annular space via the slot 80. Just that is fine.

That is, a circular cross-section passage 82 passing through each vane is closed by a frusto-conical valve body 84 slidable on a spindle 86.

The spindle 86 has a bent end 88 which is secured to the vane near the passageway by a screw 90.

With the valve body pressed against the valve seat as shown in Figure 4, one side of the vane is shielded from the slot 80 and the other side 78 is in free communication with the slot, creating a pressure drop on this side of the vane. and allow suction of liquid from the inner annular space.

During the return rotational movement to perform the non-acting return stroke, the valve body is lifted off the valve seat by the changed pressure differential, allowing free flow between the sides of the vane.

The diametrically opposed valves are oriented in opposite directions, such that during the working stroke both valves are pressed against the valve seat.

In both of the illustrated embodiments, the free flow passageway allows near instantaneous liquid delivery at a flow rate sufficient to prevent undesirable pressure drops, and the mechanism is within the thickness of the vane. It's settled.

In this way, a given function can be achieved independently of the position of the rotor within its range of motion and without any restriction of this range of motion.

The present invention is not limited to the illustrated embodiment, but can be modified in many ways.

For example, the annular space serving as a reservoir for the buffer liquid may be part of a large-volume reservoir or may be formed as one of a number of reservoirs, or in the case of the illustrated die-cast loaf as a stuffing member. Even if it is removed, there is no significant decrease in efficiency.

Furthermore, the illustrated example is a dashpot having a rotor with two diametrically opposed vanes, or is applicable to a single vane rotor or a rotor having two or more vanes.

[Brief explanation of drawings]

1 and 2 are views showing a double-acting dashpot according to the present invention, in which FIG. 1 is a plan view showing a partial cross section with the cover of the casing removed, and FIG. 2 is a sectional view in the axial direction;
3 is a side view of a rotor for a single-acting dashpot according to the present invention, and FIGS. 4 and 5 are lines A in FIG. 3, respectively.
- person, sectional view along line B-B; In the figure, 2...Casing, 4...
・Rotor, 6.8...Bearing, 10...
...Axis, 12...Subline, 14...
・Hollow boss, 20... Vane, 26...
・Sealing sleeve, 28, 32... Clasp, 3
4... Gap, 36... Annular space, 38
・・Kunpatsukinkling, 40・・・・Gap, 44
... circulation passage, 46 ... hole, 48 ... valve body, 52 ... control, 62 ... filling member,
70... Loaf, 72... Hollow Boss,
76... Filling member, 80... Slot, 84... Valve body, 86... Spindle.

Claims (1)

[Claims] 1. Filling the chamber 18 in the housing 2 with a liquid,
A rotor 4, 70 having at least one vane 20 in the chamber is rotatably provided and configured to provide damping by forced fluid flow between opposite sides of the vane, and a hollow boss 14, 72 is provided on the rotor. is provided to form an inner space 36 that serves as a reservoir for fluid, and a fluid communication mechanism 46.80 is provided within the rotor to provide substantially unrestricted fluid communication from the reservoir through the rotor to the pressure drop region of the chamber 18. In a semi-rotary dashpot configured to permit fluid flow, a flexible sealing sleeve 26 is provided between the housing 2 and the rotor 4° 70 so that at least a portion of the sealing sleeve is within the boss of the rotor. A dashpot characterized in that the sealing sleeve extends over the reservoir and forms a radially inner wall of the reservoir. 2. The dashpot of claim 1, wherein the fluid communication mechanism has a passage controlled by a valve, and the sealing sleeve 26 is exposed to ambient pressure;
Dashpot characterized in that the passage opens when a predetermined pressure drop relative to ambient pressure occurs in the chamber region. 3. A dashpot according to claim 1 or 2, wherein the fluid communication mechanism of the rotor has at least one passageway 46.80 opening directly into the reservoir on the opposite side of the sealing sleeve. A dashpot characterized by: 4. In the dashpot according to any one of claims 1 to 3, the rotor is a die-cast part having a plurality of vanes 20, and the fluid communication mechanism is formed during die-cast molding of the rotor. A dashpot characterized in that it has a slot-shaped passage 46.80 extending from each vane into the hollow boss, shaped as an open-ended groove. 5. In the dashpot according to claim 4, a filling member 62 is provided at the end of the groove of the die-cast rotor.
．． 76 is inserted to close the end portion. 6. The dashpot according to claim 1, wherein the vane of the rotor is provided with a communication mechanism having passages 80, 82 communicating between both sides of the vane to allow interconnection of chamber regions on both sides of the vane; To allow free movement of the rotor in the return direction, the dashpot is preferably constructed as a single-acting type, and the passages 80, 82 are also connected to the reservoir 36, and a valve 84 is fitted in the passage to the rotor. When the rotor moves in the direction of action, the flow from the high pressure side of the vane to the reservoir can be blocked, but when the rotor moves in the opposite direction, the high pressure side of the vane is opened so as to communicate with both the opposite side of the vane and the reservoir. A dashpot characterized by being installed in.