Pump device unifying a reservoir and method for attaching the reservoir to the pump device

Abstract

A pump device unifying a reservoir is disclosed. The pump device comprises a pump housing, a bracket, bolts and nuts. The pump housing comprises a front and a rear housing. The bracket is attached to the reservoir at one end thereof. The bolt has a bolt head at an intermediate portion thereof, a first thread portion formed on one side thereof and a second thread portion formed on the other side thereof, which a diameter of the first thread portion is larger than the same of the second thread portion. The nut engages to the second thread portion. The rear housing is secured to the front housing by screwing the first thread portion to the front housing through the rear housing. The nut is screwed to the second thread portion so that the other end of the bracket is fixed between the bolt head and the nut.

Description

INCORPORATION BY REFERENCE

[0001] The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2002-50873, filed on Feb. 27, 2002. The contents of that application are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a pump device on which a reservoir is attached being unified and a method for attaching the reservoir to the pump device.

[0004] 2. Discussion of the Background

[0005] A pump device that a reservoir is unified with in order to simplify a pipe arrangement thereof is known as using for a power steering apparatus of an automobile. A conventional pump device shown by FIG. 1 consists of a pump 2, a reservoir 3 attached with the pump 2 and attaching elements which comprise a bracket 4 and a couple of bolts 5. The bracket 4 consists of a main body 4a which is integrated with an undersurface of the reservoir 3 and a pair of arm portions 4b which are bent like a L-shape at the ends of the main body 4a. As shown by FIG. 2, each arm portion 4b is inserted between a rear housing 7 of the pump 2 and head 5a of each bolts 5, and fixed with the rear housing 7 and a front housing 6 of the pump 2 by the bolts 5 in order to unify the reservoir 3 to the pump 2. In this way, the bolts 5 work used for both of securing the rear housings 7 to the front housing 6 and fixing the bracket 4 to the pump 2. Then, since both of through holes 9 formed on the arm portion 4a and through holes 7a formed on the rear housing 7 are loose hole, it is difficult to tighten the bolt 5 with positioning both of rear housing 7 and the bracket 4 exactly. Therefore, it is possible that rear housing 7 or the bracket 4 is not secured in exact position. Further, a performance inspection of the pump 2 is usually executed after the pump 2 is assembled, but before the bracket 4 is fixed to. Therefore, the bolts 5 have to be pulled out in order to fix the bracket 4 after the performance inspection, and be screwed again after being inserted into the through hole 9 of the arm portions 4b. Then, it is possible that extraneous substances are put into the pump 2 and performance of the pump 2 changes because the bolts 5 which secures the rear housing 7 to the front housing 6 are loosened and pulled out. When the reservoir 3 has to be exchanged for new one in aftermarket, the same problems are concerned.

SUMMARY OF THE INVENTION

[0006] In view of the foregoing, it is an object of the present invention to provide an improved pump device. In order to achieve the above and other objects, a first aspect of the present invention provides a pump device unifying a reservoir. The pump device comprises a pump housing, a bracket, a bolt and a nut. The bracket is attached to the reservoir. The bolt has a bolt head in an intermediate portion thereof. A first thread portion is formed at one side of the bolt and a second thread portion is formed at the other side of the bolt. The first thread portion is screwed into the pump housing. The nut screwed to the second thread portion so as to secure the bracket with the bolt head.

[0007] A second aspect of the present invention provides a method for attaching a reservoir to a pump device. The method comprises preparing a bolt, a bracket and a nut. The bolt has a bolt head at an intermediate portion thereof, a first thread portion formed on one side thereof and a second thread portion formed on the other side thereof. The bracket is attached to the reservoir at one end thereof. The nut engages to the second thread portion. The bolt is secured to the pump device so as to screw the first thread portion. The nut is screwed to the second thread portion so that the other end of the bracket is fixed between the bolt head and the nut.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various other objects, features and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiments when considered in connection with the accompanying drawings, in which:

[0009] FIG. 1 is a front view of a conventional pump device;

[0010] FIG. 2 is a cross sectional view along II-II of FIG. 1;

[0011] FIG. 3 is a front view of a pump device unifying a reservoir according to an embodiment of the present invention; and

[0012] FIG. 4 is a cross-sectional view along IV-IV of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Embodiment of the present invention will be described with reference to the drawings. FIG. 3 and FIG. 4 show a pump device as the embodiment of the present invention. The pump device, for instance that is used for a power steering apparatus, consists of a pump 10 such as vane pump, a reservoir 11 and attaching elements which are a bracket 12 and a couple of bolts 13. The bracket 12 consists of a main body 12a which is integrated with an undersurface of the reservoir 11 and a pair of arm portions 12b which are bent like a L-shape at the end of the main body 12a. Each bolt 13 comprises a bolt head 13a which is located at an intermediate portion thereof and is shaped into a hexagon for being engaged with a wrench. A first thread portion 13b is formed on one side of the bolt 13, and a second thread portion 13c is formed on the other side of the bolt 13, which a diameter of the first thread portion 13b is larger than the same of the second thread portion 13c and a length of the first thread portion 13b is longer than the same of the second thread portion 13c. The first thread portion 13b is screwed into a front housing 16 of the pump 10 through a through hole 17 of a rear housing 15 of the pump 10 in order to secure the rear housing 15 to the front housing 16 so as to be turned by the wrench engaging the bolt head 13a. A nut 18 is screwed to the second thread portion 13c in order to fix the arm portion 12b of the bracket 12 between the bolt head 13a and the nut 18 so that the second thread portion 12c goes through a U-shape slot 12c formed at each end of the arm portion 12b. The U-shape slot 12c is formed with the arm portion 12b in this embodiment, however a through hole can be adapted instead of the U-shape slot 12c.

[0014] An order of an assembling and a performance inspection for the aforementioned pump device will be described. First, the pump 10 is assembled so that the rear housing 15 is secured to the front housing 16 after components of the pump 10 is put together into the front housing 16. Then, the bolts 13 and other bolts 14 are used. The first thread portion 13b of the bolt 13 is screwed into the front housing 16 through the through hole 17 of the rear housing 15 in order to secure the rear housing 15 to the front housing 16. Next, the performance inspection of the pump 10 is executed. After the inspection, each arm portion 12b of the bracket 12 is inserted so that the second thread portion 12c goes through the U-shape slot 12c, and the bracket 12 is fixed to the pump 10 to screw the nut 18 to the second thread portion 13c.

[0015] According to the aforementioned embodiment, performance of the pump 10 does not change and there is no fear that extraneous substances are put into the pump 10 after the inspection or when the reservoir 11 is exchanged in aftermarket, because it is not necessary that the bolts 13 are pulled out. Further, assembling time of the reservoir 11 can be reduced and it becomes easily that the rear housing 15 and the bracket 12 are secured in exact position, because the rear housing 15 and the bracket 12 are not secured simultaneously. Furthermore, the bolts 13 are not turned when the nuts 18 are screwed if the bolt head 13a and the nut 18 are tightened by same power, because the diameter of the first thread portion 13b is larger than the same of the second thread portion 13c.

[0016] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is thereby to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

Claims

1. A pump device unifying a reservoir comprising: a pump housing; a bracket attached to the reservoir: a bolt having a bolt head at an intermediate portion thereof, and formed a first thread portion on one side thereof and a second thread portion on the other side thereof, wherein the first thread portion is screwed into the pump housing; and a nut screwed to the second thread portion so as to fix the bracket with the bolt head.

2. A pump device unifying a reservoir according to claim 1, wherein: the bracket has a U-shape slot which the second thread portion goes through.

3. A pump device unifying a reservoir according to claim 1, wherein: the bracket has a through hole which the second thread portion goes through.

4. A pump device unifying a reservoir according to claim 1, wherein: a diameter of the first thread portion is larger than a diameter of the second thread portion.

5. A pump device unifying a reservoir according to claim 1, wherein: a length of the first thread portion is longer than a length of the second thread portion.

6. A method for attaching a reservoir to a pump device, comprising: preparing a bolt which has a bolt head at an intermediate portion thereof, a first thread portion formed on one side thereof and a second thread portion formed on the other side thereof; preparing a bracket which is attached to the reservoir at one end thereof; preparing a nut which engages to the second thread portion; securing the bolt to the pump device so as to screw the first thread portion; and screwing the nut to the second thread portion so that the other end of the bracket is fixed between the bolt head and the nut.

7. A method for attaching a reservoir to a pump device according to claim 6, wherein: the pump device comprises a front housing and a rear housing; and the rear housing is secured to the front housing by screwing the first thread portion to the front housing through the rear housing.

8. A method for attaching a reservoir to a pump device according to claim 7, wherein: a performance inspection of the pump device is executed after the rear housing is secured to the front housing and before the bracket is fixed.