JP6120486B2 - Vane wear prediction structure of vane machine - Google Patents

Description

  The present invention relates to a vane wear prediction structure of a vane machine that enables prediction of vane wear by deterioration operation.

  In an electric vehicle (electric vehicle) that runs on a motor using a secondary battery as an electric power source, an electric vacuum pump represented by a vane mechanism is used to secure the negative pressure required for the assist brake system (ensuring assist force). Is adopted.

  The vacuum pump (vane mechanism) employs a structure in which a circular cylinder chamber having a suction hole and a discharge hole, a rotor rotatably accommodated in the cylinder chamber, and a plurality of vanes (plate shape) are combined. In many cases, a plurality of vane grooves are formed radially on the outer peripheral surface of the rotor, and the base end side of the vane is retractably retracted into these vane grooves so that the tip of the vane contacts the inner peripheral surface of the cylinder chamber. (By centrifugal force or a spring member) is used, and the negative pressure is generated by sliding the vane along the inner peripheral surface of the cylinder chamber as the rotor rotates.

  When such negative pressure is generated, the tip of the vane wears because it is in sliding contact with the inner peripheral surface of the cylinder chamber. Normally, as the wear progresses, the vane is gradually drawn out from the inside of the vane groove. However, when the vane is drawn out until the wear limit is reached, the vane is not sufficiently strong (because the total length of the vane becomes short). May break.

  Vacuum pumps used in braking systems wear vanes in proportion to their operating time, so if the vane reaches the wear limit, the vacuum pump function suddenly fails, greatly affecting the braking system. . In particular, a vacuum pump that uses a vane formed of a carbon member and lubricates around the vane without using lubricating oil is susceptible to such wear.

For this reason, the vacuum pump employs a vane that can withstand the normal use period, thereby extending the life of the vane so that the pump function is not lost. Nevertheless, it is conceivable that the wear of the vane reaches the wear limit depending on the usage situation beyond the expected.
Conventionally, as disclosed in the cited documents 1 and 2, only a technique has been proposed in which a groove is formed on the side surface of the vane to increase the airtightness of the vane or to improve the lubricity of the vane. .

Japanese Utility Model Publication No. 62-108582 Japanese Patent Laid-Open No. 2-11885

For this reason, there was no reason to know the situation before the vane wear limit was reached.
Accordingly, an object of the present invention is to provide a vane wear prediction structure for a vane machine that can predict that the wear of the vane is close to the wear limit due to the rapid performance deterioration.

  In order to achieve the above object, the invention of claim 1 penetrates through a predetermined position of the vane portion accommodated in the vane groove in the thickness direction of the vane, and the opening is normally closed by the wall surface of the vane groove. When the wear of the vane proceeds by a predetermined amount, the penetrating part appears outside the vane groove.

With this configuration, when the vane wears up to a predetermined amount due to the operation of the vane machine, the through portion appears outside the vane groove. Thereby, the cylinder chambers on both sides of the vane that should be partitioned by the vanes communicate with each other through the penetrating portion. Then, it will be changed to a driving whose performance is considerably deteriorated rather than the driving that has exhibited normal performance so far.
From this deliberately induced degradation operation, it is predicted that the current situation has approached a situation where performance degradation may occur rapidly due to vane wear, that is, the vane is approaching the wear limit. Can be done.

According to the invention of claim 2, the penetrating portion is arranged in the region immediately before the wear limit of the vane so that the prediction that the vane is approaching the wear limit can be accurately performed.
In the invention of claim 3, further, the penetrating portion is arranged in a triangular shape with the apex angle portion facing the vane tip and the bottom portion facing the vane base end so that the performance of the vane machine does not deteriorate rapidly. Was made.

In the invention of claim 4, the penetrating part is formed by a hole or a notch so that the penetrating part can have a simple structure.
According to the invention of claim 5, the vane is formed of a carbon member so that the vane can be effectively exhibited in a vane machine (non-lubricating type) using a carbon vane, in which wear of the vane is likely to appear remarkably. Was used.
The invention of claim 6 is applied to a vacuum pump for supplying negative pressure in the assist brake system of the vehicle so that the prediction function is sufficiently exhibited in the assist brake system of the vehicle that requires high safety and reliability.

According to the first aspect of the invention, by using the penetrating portion formed in the vane to intentionally induce the deterioration operation of the vane machine, it approaches a situation in which performance deterioration may occur suddenly due to vane wear. That is, it can be predicted that the vane wear is approaching the wear limit.
That is, it is possible to predict that the vane has approached the wear limit that causes rapid performance deterioration from the determination of the operation state of the vane mechanism. Moreover, the prediction can be made with a simple structure in which a penetration is provided in the vane.

According to the invention of claim 2, it is possible to accurately predict that the vane wear is approaching the wear limit.
According to the third aspect of the present invention, it is possible to predict without any problem that the vane machine is immediately before the vane wear limit due to the gradual deterioration of operation without abruptly degrading the performance of the vane machine.
According to the invention of claim 4, the penetrating portion can be a simple structure.

According to the invention of claim 5, it is effective for a vane mechanism using a carbon vane that does not use lubricating oil and lubricates around the vane by itself.
According to the invention of claim 6, in the vehicle assist brake system that requires high safety and reliability, the prediction function can be sufficiently exhibited.

The front view which carried out the partial cross section which shows the electric vacuum pump (vane mechanism) which concerns on the 1st Embodiment of this invention with the assist brake system of the electric vehicle which employ | adopted the vacuum pump. The disassembled perspective view which shows the structure of each part in the pump part of the same electric vacuum pump. The perspective view which shows the vane of a pump part with the penetration part formed in the vane. The side view of the pump part which shows the driving | running state in the normal time of the pump part. The side view of the pump part which shows the driving | running state at the time of the wear limit of the same pump part. The principal part of the 2nd Embodiment of this invention is shown, (a) is a front view of a vane, (b) is a bottom view of a vane. The principal part of the 3rd Embodiment of this invention is shown, (a) is a front view of a vane, (b) is a bottom view of a vane.

Hereinafter, the present invention will be described based on a first embodiment shown in FIGS.
FIG. 1 shows an electric vacuum pump (corresponding to the vane mechanism of the present application) to which the present invention is applied, together with an assist brake system of an electric vehicle (electric vehicle) incorporating the pump, and FIGS. 2 and 3 show the components of the electric vacuum pump. The structure is shown.

  First, an outline of the assist brake system a will be described with reference to FIG. 1. In the figure, 1 is a dash panel that partitions the inside and outside of a compartment 2 of an electric vehicle (electric vehicle), and 4 is installed on the lower side of the dash panel 1. The negative pressure booster 5 is a hydraulic master cylinder device connected to the output side of the booster 4. A brake pedal 8 is provided at the end of the operating rod 6 extending from the booster 4 to the vehicle compartment 2 through the diaphragm plate 4a built in the same.

  In addition, a brake device (not shown) such as a disc brake or a drum brake that applies a braking force to each wheel (front and rear wheels) of the electric vehicle is connected to the hydraulic output portion 5a of the master cylinder device 5 via a hydraulic pipe 9. When the brake pedal 8 is connected and the brake pedal 8 is depressed, the hydraulic pressure can be supplied to the brake device of each wheel through the booster 4 and the master cylinder device 5 (applying brake force).

  Since an electric vehicle does not have an engine that is a source of negative pressure unlike a vehicle equipped with an engine, a vacuum pump that is a vane machine, such as an electric vacuum pump 10, is usually provided at the negative pressure inlet 4 b of the booster 4. Is connected. Thus, the negative pressure required for assisting the brake operation is supplied from the electric vacuum pump 10 to the booster 4. Incidentally, the electric vacuum pump 10 and the booster 4 are connected by a connection hose 11 to constitute the entire assist brake system a.

The electric vacuum pump 10 includes, for example, a rotary vane type pump unit 14 connected (directly connected) to an output shaft 12a (rotary shaft) of a horizontally oriented motor unit 12, and a bottomed cylindrical pump cover 15 around the pump unit 14. The structure covered with is used.
Specifically, as shown in FIG. 2, the pump portion 14 is provided with flat pump covers 18 a and 18 b on both sides of the pump ring 16 to form a circular cylinder chamber 19 therein. A circular rotor 21 connected to the output shaft 12 a of the motor unit 12 is accommodated in the cylinder chamber 19. The rotor 21 is arranged at a position eccentric from the center of the pump ring 16 (cylinder chamber 19), and is configured to be rotationally driven around this eccentric position.

  A plurality of vanes 23 are installed on the outer peripheral surface of the rotor 21 so as to advance and retreat. Specifically, a plurality of vane grooves 25 are formed on the outer peripheral surface of the rotor 21 in the width direction. Each vane 23 uses a vane formed in a plate shape with a carbon member so that smooth sliding can be performed without using lubricating oil (non-lubricating oil type). Each vane 23 is formed in a square shape having a dimension corresponding to the width dimension (pump ring width) of the vane groove 25. The base end side of each vane 23 is slidably accommodated in each vane groove 25 so that each vane 23 can be ejected from the distal end side to the periphery (can be advanced and retracted). That is, each vane 23 protrudes outward by the centrifugal force generated by the rotation of the rotor 23.

  The tip of each vane 23 comes into contact with the inner peripheral surface of the pump ring 16 to partition the cylinder chamber 19, and each vane 23 moves in contact with the inner peripheral surface of the cylinder chamber 19 as the rotor 21 rotates. (Sliding), for example, from a suction hole 27 formed in the pump cover 18a, for example, a negative pressure outlet portion 16a (shown in FIG. 1) provided in the pump ring 16, and a connecting hose connected to the negative pressure outlet portion 16a 11, the air in the booster 4 is scraped out. That is, the scraped air is discharged to the outside (outside air) from, for example, a discharge hole 28 formed in the pump cover 18a, and the negative pressure generated by the electric vacuum pump 10 is negative pressure chamber 4c partitioned by the diaphragm plate 4a. Supplied to. Thus, the negative pressure generated by the electric vacuum pump 10 is supplied to the booster 4 using the brake operation as an assist force.

  Here, as each vane 23, a vane having a performance that can sufficiently withstand a normal assumed usage period is employed. In other words, each vane 23 strives to extend its life and prevent breakage in an assumed use situation. Even so, it is conceivable that the wear of each vane 23 reaches the wear limit and causes breakage depending on the usage situation more than expected. The non-lubricated type has a high tendency because carbon vanes are used as a lubricant.

  Therefore, each vane 23 is provided with a vane wear prediction structure that makes it possible to predict that the wear limit of the vane 23 has been approached, as shown in FIG. When the wear of the vane 23 approaches the wear limit, the electric vacuum pump 10 is intentionally brought into an operation in which the performance is considerably deteriorated rather than an operation in which normal normal performance is exhibited. The vane wear prediction structure is the same for each vane 23.

  Explaining the vane wear prediction structure, as shown in FIGS. 3A and 3B, the penetrating portion 30 penetrates the vane portion of the vane 23 in the thickness direction at a predetermined position of the vane groove 25. It is provided and configured. Here, for example, a combined structure of a circular hole 30 a provided in the center in the width direction of the vane 23 and a square notch 30 b formed at both ends in the width direction of the vane 23 is used for the through portion 23. ing. The through portion 30 may be only the hole 30a, the notch 30b, or another through structure.

  When the penetrating portion 30 has a position from the tip of the vane 23 to the plate portion separated by a predetermined dimension L1, the point α of the wear limit (a portion where a sudden pump function failure occurs due to vane wear) is a point α. It is provided at a point in front of the wear limit. For example, the penetrating portion 30 is provided immediately before the wear limit. When the vicinity of the wear limit of the vane 23 reaches the inner peripheral surface of the cylinder chamber 19, the opening of the penetrating portion 30 opens with respect to the cylinder chamber 19 at the initial stage of suction. The structure starts to be exposed.

  Thus, as the wear of the vane 23 approaches the wear limit, the through portion 30 (hole 30a, notch portion 30b) appears outside the vane groove 25, that is, inside the cylinder chamber 19, and is partitioned by the vane 23. The chambers on both sides of the vane that are supposed to be communicated with each other through the penetrating portion 23, and the operation is changed to an operation in which the pump performance is intentionally deteriorated.

With this structure, it is predicted that the wear of the vane 23 is approaching the wear limit.
That is, as shown in FIG. 4, in the electric vacuum pump 10, as the rotor 22 is driven (rotated) by the motor unit 12, each vane 23 on the outer peripheral surface protrudes outward by centrifugal force, The portion is pressed against the inner peripheral surface of the cylinder chamber 19.

  Then, each vane 23 moves while being in contact with the inner peripheral surface of the cylinder chamber 19. At this time, due to a change (small) in the space volume of the chamber partitioned by each vane 23, air is scraped out from the suction hole 27 and exhausted from the discharge hole 28 to the atmosphere. Thereby, the negative pressure generated by the electric vacuum pump 10 is applied to the booster 4.

By the operation of the electric vacuum pump 10 (normal operation), wear at the tip of each vane 23 gradually proceeds.
At this time, it is assumed that the wear has progressed until the tip of the vane approaches the wear limit (assuming that the pump performance is suddenly lost) due to the operation of the pump function exceeding the assumption (blade total length: small).
Then, as shown in FIG. 5, the holes 30 a and 30 b (penetrating portion 30) arranged in the vane groove 25 appear outside from the vane groove 25 according to the progress of wear of the vane 23. Come (initially).

  As a result, as shown in FIG. 5, the initial-stage chamber that should be partitioned by the vane 23 starts to communicate with the adjacent chamber through the hole 30 a and the notch 30 b that appear in the cylinder chamber 19. Then, the air that should be trapped in the chamber 19a (state A1 in FIG. 4) leaks into the adjacent chamber through the hole 30a and the notch 30b (state A2 in FIG. 5). Due to the occurrence of this leakage, the electric vacuum pump 10 is not an operation that exhibits the normal pump performance until then, but a considerably deteriorated pump operation in which the performance of scraping air is inferior.

  From the deterioration operation of the electric vacuum pump 20 that is intentionally induced by the through-hole 30, the current operation state of the electric vacuum pump 20 may be a situation in which the pump function may be lost due to vane wear (abrupt performance It can be recognized that the situation is approaching. That is, it is possible to determine, that is, to predict that the vane 23 is approaching the wear limit from the change in the operating state of the electric vacuum pump 20 caused by the through portion 30.

  Therefore, from this prediction, it is possible to avoid an unexpected situation in the electric vacuum pump 10 (vane machine). Moreover, it is possible to know the replacement time of the vane 23, and it is possible to improve safety and reliability. In addition, the vane wear prediction structure can be a simple structure by simply providing the vane 23 with the through-holes 30 such as the hole 30a and the notch 30b. It is effective for the electric vacuum pump 10 (vane machine) that uses the vane 23 made of carbon and does not require lubricating oil (non-lubricating oil type).

In particular, by forming the penetrating portion 30 near the wear limit of the vane 23, it can be accurately predicted that the vane 23 is in a state immediately before the wear limit.
Moreover, the assist brake system a using the electric vacuum pump 20 can avoid a situation in which the assist function is damaged even if the electric vacuum pump 20 is operating beyond the assumption. High safety and reliability can be achieved.

FIG. 6 shows the main part of the second embodiment of the present invention.
In the present embodiment, a hole 30c having a triangular shape, for example, an isosceles triangular shape, is used as the penetrating portion 30. Specifically, the triangular hole portion 30c is arranged such that the apex angle portion is directed to the vane tip and the side portion serving as the base is directed to the vane base end, and the opening area gradually increases from the vane tip portion toward the vane base portion. The opening shape changes greatly, and the opening area gradually appears in the cylinder chamber from the small side as the vane 23 approaches the wear limit.

  In this way, the deterioration operation of the electric vacuum pump that is performed to notify that the vane 23 has approached the wear limit is not performed rapidly, and the performance gradually deteriorates, that is, the operation gradually deteriorates. As a result, the function of the electric vacuum pump and the assist brake system using the electric vacuum pump can be prevented from changing suddenly, and the influence on the electric vacuum pump and the assist brake can be avoided as much as possible. It can be predicted that the vane 23 is just before the wear limit.

FIG. 7 shows the main part of the third embodiment of the present invention.
This embodiment is a modification of the second embodiment, and is not a triangular hole, but is formed from an elliptical hole 30d arranged with its long axis direction directed toward the full length direction of the vane 23.
Even with such an opening shape, the same effects as in the second embodiment can be obtained.
However, in FIG. 6, 7, the same code | symbol was attached | subjected to the same part as 1st Embodiment mentioned above, and the description was abbreviate | omitted.

  Of course, the vane wear prediction structure of the present invention is not limited to the first to third embodiments described above, and may be implemented in various ways without departing from the gist of the present invention. For example, in the first to third embodiments, the present invention is applied to an electric vacuum pump for vehicle braking. However, the present invention is not limited to this, and the present invention may be applied to a vane machine using other vanes. Of course, the present invention may be applied to a vane machine such as a vane compressor in which the vane is not provided in the rotor but the vane is provided in the cylinder chamber and the vane tip is in contact with the outer peripheral surface of the rotor.

10 Electric vacuum pump (vane machine)
19 Cylinder chamber 22 Rotor 23 Vane 25 Vane groove 27 Suction hole 28 Discharge hole 30 Through part a Assist brake system

Claims (6)

A circular cylinder chamber, a rotor provided in the cylinder chamber, and a base end side is housed in a vane groove formed on one of an inner peripheral surface of the cylinder chamber and an outer peripheral surface of the rotor so as to freely advance and retract. A vane that is in contact with the other peripheral surface, and the vane is fed out of the vane groove due to wear at a tip portion.
In a predetermined position of the vane portion accommodated in the vane groove of the vane, a penetrating portion is provided that penetrates in the thickness direction of the vane and is normally closed by the wall surface of the vane groove;
The vane wear prediction structure for a vane machine, wherein when the wear of the vane proceeds by a predetermined amount, the through portion appears outside the vane groove. The vane wear prediction structure for a vane machine according to claim 1 , wherein the penetrating portion is disposed near a wear limit of the vane. The through portion toward an apex angle portion to the vane tip, the side portions comprising a base disposed towards the vane base end, to claim 1 or claim 2, characterized in that it Na triangular Vane wear prediction structure of the described vane machine.   The vane wear prediction structure for a vane machine according to any one of claims 1 to 3, wherein the through portion is formed by a hole or a notch.   The vane wear prediction structure for a vane machine according to any one of claims 1 to 4, wherein the vane is formed of a carbon member.   The vane wear prediction structure for a vane machine according to any one of claims 1 to 5, wherein the vane machine is a vacuum pump that supplies a negative pressure in an assist brake system of a vehicle.

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