JP2006009580A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump hardly causing erosion by cavitation even in severe conditions of higher pressure and larger capacity than conventional ones. <P>SOLUTION: In a passage communicating with a low pressure side passage 3 via a return passage 4 from a high pressure side passage 2 of a flow regulating valve 1, a part around a projecting part 5 formed at the low pressure side passage 2 to balance the fluid force of an operating fluid flowing in at high pressure from the return passage 4, is formed of material harder to erode than the material of a vane pump body 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vane pump used when supplying a working fluid to a supply / discharge destination (actuator) using hydraulic pressure, represented by a power steering device of an automobile.

  Normally, this type of vane pump has a large pressure difference of, for example, a maximum of 7.84 to 16.2 MPa (80 to 165 kgf / Cm 2) between the low-pressure suction side and the high-pressure discharge side, and a maximum of 10,000 revolutions / Suction-discharge of 2 times / rotation is repeated according to the rotor rotating at high speed in minutes.

  Recently, this type of vane pump is not limited to a power steering device, but may be used in parts that have not been controlled symmetrically in the past in order to ensure driving stability and comfort of an automobile. Yes, at that time, regardless of the number of rotations of the vane pump, the working fluid may always be used or not used with a large capacity. Corrosion caused by cavitation in the low-pressure channel (bypass channel) into which the high-pressure working fluid flows This is an important solution.

  The situation will be described using the technique of the flow control valve described in Patent Document 1.

  FIG. 3A is a longitudinal sectional view showing an example of a vane pump provided with this flow control valve, and FIG. 3B is a sectional view taken along the line X1-X and X2-X.

  The vane pump 20 is a flow control valve 11 shown in FIG. 3B, a high-pressure side passage 12 that is a discharge passage for the working fluid pressurized by the pump, an inflow passage for the working fluid, and sucks excess oil. A low pressure side flow path 13 that functions as a flow path returning to the side, a reflux path 14 from the high pressure side flow path 12 to the low pressure side flow path 13, and a low pressure side flow path 13 into which a high pressure working fluid flows from the reflux path 14. The overhang part 15 provided and the sleeve 16 used for the flow control valve 11 part are provided, and these are the principal part parts relevant to the present invention.

  3B, the X1-X cross section in which the low pressure side flow path 13 can be seen and the X2-X cross section in which the high pressure side flow path 12 can be seen overlap each other as shown in FIG. It is a thing.

  In addition, the vane pump 20 includes a rotor 17 that is the basis of the pump function, a vane 17a that is accommodated so as to be able to enter and exit the rotor 17, a cam ring 17b that forms an inner peripheral surface with which the vane 17a protruding from the rotor 17 abuts. A cover 18a that restricts both sides of the rotor 17 and the like, a side plate 18b, and a main body 18 that accommodates these are provided, and functions as a vane pump. Since this pump function is not different from that of a normal vane pump, detailed description thereof is omitted.

  As shown in FIG. 3B, the flow control valve 11 of the relevant part includes a valve pipe 11a that accommodates the valve, a plunger 11b that is a valve body, a spool 11c that is integrated with the plunger 11b, A check valve 11d that is installed in the spool 11c and controls the flow of the working fluid from the left to the right in the spool 11c, a spring 11e that urges the spool 11c to the right, and a right opening of the valve line 11a are sealed. An orifice member 11f that serves as a valve seat for the tip of the plunger 11b is provided. Reference numeral 18d is a connection member for connecting a load device as a supply / discharge destination.

  Since this exemplary pump is a high-pressure, high-speed rotary pump, the spool is made of a material that is hard to be eroded (for example, iron) in order to prevent erosion of the internal portion due to cavitation.

  On the other hand, the main body 18 is manufactured from aluminum (usually aluminum die cast) which is a soft material for the purpose of reducing the cost and weight of the pump itself.

  If the main body 18 and the spool are slid, the material soft side of the main body 18 is worn, and therefore, it is necessary to interpose a sleeve having the same hardness as the spool.

  Thus, the sliding surface is not easily worn by sliding of the spool. The reflux path 14 and the overhang part 15 will be described later.

  In the vane pump 20, the power flow control valve 11 is a power steering device in which the working fluid discharged to the high-pressure side flow path 12 by the rotor 17 that constantly rotates in response to the rotational force from the engine of the automobile is connected to the connecting member 18d. 3 (a) and 3 (b) show the normal operation state in which control is performed so that only an appropriate amount of pressure is supplied as required by the load equipment.

  In this state, the spool 11c including the plunger 11b is biased by the spring 11e to the spool 11c, the pressure of the working fluid in the high-pressure side passage 12, and the pressure of the working fluid on the load device acting on the tip of the plunger 11b. 3 (b), it is possible to supply an appropriate amount of the working fluid.

  At this time, the surplus working fluid returns from the high-pressure channel 12 to the low-pressure channel 13 as shown as a flow FC in FIGS. Therefore, the portion where the reflux occurs is conceptually referred to as the reflux path 14.

  In this reflux path 14, as a knowledge of hydrodynamics, when the center of the spool 11 c is set as the axis of symmetry, the plunger 11 b existing in the reflux path 14 is recirculated from the high pressure side channel 12 to the low pressure side channel 13 in only one direction. Therefore, it is known that an unbalanced fluid force is generated, and the spool 11c is slid in the sleeve 16 in a biased state.

  For this reason, the overhanging portion 15 is provided with a certain overhang at a position facing the low pressure side flow path 13, whereby the fluid force is balanced and the spool 11 c is not biased in the sleeve 16. It can be slid.

  The overhanging portion 15 is formed by simultaneously processing the low pressure side flow path 13 after the sleeve 16 has been inserted into the valve line 11a first. In the case of the sleeve 16 having a thickness that allows for wear, it is inevitable that the overhanging portion 15 reaches the vane pump main body 18.

Therefore, since this overhanging part 15 is a part of the low-pressure side flow path 13, the high-pressure working fluid from the high-pressure side flow path 12 suddenly becomes a low pressure and cavitation tends to occur. The material is also easily eroded (aluminum die-casting, which is the material of the main body 18), and is easily eroded by cavitation. Improvement of the vane pump that can be used for high pressure and large capacity has been desired. .
Japanese Patent Laid-Open No. 9-170569 (FIG. 1)

  The present invention is intended to improve the above situation, and an object of the present invention is to provide a vane pump that is less likely to cause erosion due to cavitation even under severe conditions of higher pressure and larger capacity than before.

  The vane pump of the present invention is a flow path that communicates from the high pressure side flow path of the flow rate adjustment valve to the low pressure side flow path via the return path, and balances the fluid force of the working fluid that flows in at a high pressure from the return path. For the purpose of illustration, the vicinity of the overhang portion formed in the low-pressure channel is made of a material that is less eroded than the material of the vane pump body.

  In the vane pump of the present invention, the vicinity of the overhang portion formed in the low-pressure side flow path through which the high-pressure working fluid flows from the high-pressure side flow path of the flow rate adjustment valve via the reflux path is compared with the material of the vane pump main body. Since it is made of a material that is not easily eroded, it can avoid erosion of parts that cannot be eroded by cavitation, and can cope with severe conditions such as high pressure and large capacity.

  Embodiments (examples) of the present invention will be described below with reference to the drawings.

  Fig.1 (a) is a longitudinal cross-sectional view which shows an example of the vane pump of this invention, (b) is arrow sectional drawing cut | disconnected by the X1-X and X2-X.

  A vane pump 10 of FIG. 1 is used when supplying a working fluid to a power steering device such as an automobile, and discharges the working fluid pressurized by the flow control valve 1 and the pump shown in FIG. A high pressure side flow path 2 that is a flow path, a low pressure side flow path 3 that is an inflow path of a working fluid after use, a reflux path 4 from the high pressure side flow path 2 to the low pressure side flow path 3, and the low pressure side flow path 3 The overhanging portion 5 and the sleeve 6 used for the flow rate control valve 1 portion are provided, and these are the main portions of the present invention.

  In addition, the cross-sectional view of FIG. 1B overlaps the X1-X cross section in which the low pressure side flow path 3 can be seen and the X2-X cross section in which the high pressure side flow path 2 can be seen, as shown in FIG. It is a thing.

  In addition, the vane pump 10 includes a rotor 7 that is the basis of the pump function, a vane 7a that can enter and exit the rotor 7, a cam ring 7b that forms an inner peripheral surface on which the vane 7a protruding from the rotor 7 abuts, a rotor 7, and the like. A cover 8a for restricting both sides of the plate, a side plate 8b, and a main body 8 for housing them are provided, and the function as a vane pump is exhibited. Since this pump function is not different from that of a normal vane pump, detailed description thereof is omitted.

  As shown in FIG. 1 (b), the flow control valve 1, which is a relevant part of the main part, includes a valve line 1a for accommodating the valve, a plunger 1b as a valve body, a spool 1c integrated with the plunger 1b, A check valve 1d that is installed in the spool 1c and controls the flow of the working fluid from left to right in the spool 1c, a spring 1e that urges the spool 1c to the right, and a right opening of the valve pipe line 1a are sealed. An orifice member 1f serving as a valve seat for the distal end portion of the plunger 1b is provided. Reference numeral 8d is a connection member for connecting a load device as a supply / discharge destination.

  The sleeve 6 is a cylindrical body made of a material (for example, iron) that is harder and less worn than the main body 8 (usually made of aluminum die cast), and is interposed between the valve line 1a and the spool 1c, The sliding surface of the spool 1c is not easily worn by sliding, but the wall thickness is larger than that of the conventional example, and the reason and effect will be described later.

  In the vane pump 10, the function of the flow control valve 1 and the configuration and function of the other parts excluding the sleeve 6 are the same as those of the conventional example of FIG.

  The overhanging portion 5 of the vane pump 10 is also formed by simultaneously processing the low pressure side flow path 3 after the sleeve 6 has been inserted into the valve pipe 1a first. However, it is different from the conventional example in that the entire overhang portion 5 is formed so as to be formed only within the sleeve 6.

  Therefore, since this overhang part 5 is a part of the low pressure side flow path 3, even if the high pressure working fluid from the high pressure side flow path 2 suddenly becomes a low pressure and generates bubbles, the cavitation is severe. Since the material in the vicinity of the overhang portion 5 is made of a material (for example, iron) that is much harder than the material of the vane pump 10 and hard to be eroded, the erosion is very unlikely or hardly occurs. .

  Therefore, this vane pump can be used without worrying about the problem of erosion due to cavitation even in the case of high pressure and large capacity.

  Further, in this case, since the sleeve 6 itself has been conventionally used, the number of processing steps is almost the same and the cost is not increased.

  Fig.2 (a) is principal part sectional drawing of the other example of the vane pump of this invention. This sectional view is a sectional view of the same portion as FIG. 1B in a vane pump of another example.

  Compared with the vane pump 10 in FIG. 1, the vane pump 10A is such that the length of the sleeve 6A is the length of only the portion where the overhanging portion 5 is provided, and extends to the portion where the spool 11c of the flow control valve 1A is in sliding contact. There is no difference.

  Thus, in order to avoid erosion due to cavitation of the overhanging portion 5, the length of the sleeve 6A is sufficient as shown in the figure, and the effect is not changed. On the other hand, the problem of wear of the sliding contact portion between the spool 11c and the main body 8 can be solved, for example, by making the portion to the same degree of hardness as the material of the main body 8 by surface treatment or material change. .

  FIG. 2B is a cross-sectional view of a main part of another example of the vane pump of the present invention. This sectional view is a sectional view of the same portion as FIG. 1B in a vane pump of another example.

  The vane pump 10B is different from the vane pump 10 of FIG. 1 in that the overhanging portion 5 is not provided on the sleeve, but is provided at the distal end portion of the plug 6B extending from the outside of the main body 8 to this portion. The material of the plug 6B may be a material that is less likely to be eroded than the material of the main body 8, for example, iron.

  The stopper 6B can be a male screw with a hexagonal hole that is oil-tight with an O-ring 6a interposed therebetween. Even in this case, the same effect as that of the sleeve 6 of FIG. 1 can be obtained, and in this case, instead of forming the overhang portion 5 at the tip of the plug 6B, the plug 6B is correspondingly provided. It is possible to cope with this by simply making the length shorter, and the processing man-hours can be reduced.

  The problem of wear of the sliding contact portion with the spool 11c can be dealt with by the same method as in the second embodiment.

  The vane pump of the present invention can be used in all industrial fields such as control equipment that requires severe conditions of higher pressure and larger capacity, in addition to power steering devices such as automobiles.

(A) is a longitudinal sectional view showing an example of the vane pump of the present invention, (b) is a sectional view taken along the line X1-X, X2-X. (A), (b) is principal part sectional drawing of the other example of the vane pump of this invention. (A) is a longitudinal sectional view showing an example of a conventional vane pump, (b) is an arrow sectional view cut along X1-X, X2-X.

Explanation of symbols

1-1B Flow control valve 2 High-pressure side flow path 3 Low-pressure side flow path 4 Recirculation path 5 Overhang 6 Sleeve 6A Main sleeve 6B Plug 7 Rotor 7a Vane 7b Cam ring 8 Body 8a Cover 8b Side plate 10-10B Vane pump

Claims (4)

  A flow path communicating from the high pressure side flow path of the flow rate adjusting valve to the low pressure side flow path via the return path, and in order to balance the fluid force of the working fluid flowing in from the return path at high pressure, A vane pump characterized in that the vicinity of the overhang formed in the flow path is made of a material that is less susceptible to erosion than the material of the vane pump body.   The said overhang | projection part is formed in the sleeve inserted by the accommodation hole of the said flow control valve, This sleeve was comprised with the material which is harder to corrode than the raw material of a vane pump main body. Vane pump.   3. The vane pump according to claim 2, wherein the sleeve is inserted into a receiving hole of the flow rate adjusting valve and integrated with a main sleeve that protects the valve body sliding portion.   The vane pump according to any one of claims 1 to 3, wherein a material that is less likely to be eroded than a material of the vane pump main body is iron.

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