JPH0454074B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in vane pumps used as power sources for vehicle power steering systems and the like.

First, a conventional vane pump will be explained with reference to FIGS. 1 to 3. In the figure, reference numeral 1 denotes a housing that rotatably supports a drive shaft 4 through bearings 2 and 3. This housing 1 is formed with an annular recess 5 that is open at one end. A cam ring 7 that accommodates a rotor 6 splined to the drive shaft is disposed therein. A plurality of vanes 8...8 are attached to the rotor 6 so as to be freely protrusive and retractable approximately in the radial direction, and the tips of the vanes 8...8 are in sliding contact with the inner peripheral cam surface 7a of the cam ring 7, so that adjacent vanes A work room 9...9 is formed between them. This working chamber 9 changes its volume as the rotor 6 rotates,
Two suction sections where the volume increases and two compression sections where the volume decreases are formed.

Reference numeral 10 denotes a side plate, which is disposed in contact with one side of the cam ring 7 in an annular recess 5 of the housing 1, and forms a high pressure chamber 11 for discharge oil in the annular recess 5. There is. This side plate 10 is provided with a discharge port 12 recessed facing the discharge section of the working chamber 9 and a discharge passage 13 connected to the discharge port 12. is guided to the high pressure chamber 11, and therefore, the side plate 10 is pressed against the cam ring 7 by the discharge pressure in the high pressure chamber 11 and the spring force of the spring 14 tensioned in the high pressure chamber 11. ,
Oil-tightness is ensured within the work chamber 9. In addition, a plurality of through holes 15 are bored in this side plate 10, and communicate the annular groove 16 which is not continuous in the circumferential direction formed on the sliding surface with the rotor 6 and the high pressure chamber 11. Through the through hole 15 and the annular groove 16, a part of the discharged oil in the high pressure chamber 11 is guided to the base end of a plurality of vane slots 8a formed in the rotor 6, and is directed in the radial direction with respect to the vanes 8...8. It's starting to give you power. Note that 17 and 18 are seal rings for sealing the high pressure chamber 11.

19 is a flow control valve, and this flow control valve 19 is
It is provided between a high-pressure passage 20 led from the high-pressure chamber 11 and a low-pressure passage 22 connected to the suction hole 21, and the excess oil of the discharged oil collected in the high-pressure chamber 11 is transferred to the low-pressure passage 22. The discharge amount discharged from the discharge hole 23 is controlled to be constant.

A cover plate 24 is attached to the housing 1 by bolts (not shown) and closes the open end of the housing 1. The cover plate 24 includes a suction passage 25 connected to the low pressure passage 22, and a suction passage 25 connected to the low pressure passage 22. A branch passage 27 is formed that branches from the suction passage 25 and communicates with a suction port 26 that opens facing the suction section of the working chamber 9.
A portion of the suction port 26 is connected to the cam ring 7.
It opens into a through passage 28 formed through the side plate 10, and communicates with a suction port (not shown) formed as a recess in the side plate 10 through the through passage 28, thereby allowing suction into the working chamber 9 from both sides at the same time. It is designed to increase inhalation efficiency. Further, in the sliding contact surface of the cover plate 24 with the rotor 6, a discharge port 29 and an annular groove 30 which is not continuous in the circumferential direction are formed as depressions, similarly to the side plate 10. The outer shape of the cover plate 10 is approximately the same as that of the housing 1 at the joint with the housing 1. In addition, 31 is housing 1
32 is a pulley spline-coupled to the drive shaft 4; 33 is a seal between the annular recess 5 of the housing 1 and the low pressure passage at the joint between the housing 1 and the cover plate 10; 22, and this seal ring 33 is housed in a seal groove 34 formed in the housing 1 to prevent leakage of hydraulic oil.

In such a configuration, by rotating the rotor 6 via the pulley 32 and the drive shaft 4 by an engine or the like, hydraulic oil stored in a reservoir (not shown) is transferred to the suction hole 21, the low pressure passage 22, the suction passage 25,
The oil is introduced into the working chamber 9 through the branch passage 27 and the suction port 26, and then the sucked oil is transferred to the discharge ports 12, 29, the high pressure chamber 11, and the flow control valve 1.
9 and is discharged from the discharge hole 23.

In a vane pump having such a configuration, it is necessary to non-rotatably attach the cam ring 7 to the housing 1 so that the center of the inner cam surface 7a coincides with the center of the rotor 6.

Conventionally, pin holes 1a and 7b that are continuous in the radial direction are formed in the housing 1 and the cam ring 7 as shown in FIG. 4, and positioning pins 35 are inserted into these pin holes 1a and 7b to rotate the cam ring 7. However, this method had the following drawbacks.

(1) During assembly, the center of the rotor 6 and the center of the inner cam surface 7a of the cam ring 7 are offset, causing the rotor 6 to locally contact the inner cam surface 7a, causing abnormal wear of the contact portion. This may impair durability or cause vibration or noise.

This is because each component such as the housing 1, rotor 6, cam ring 7, etc. is manufactured with predetermined dimensional tolerances allowed, so when a vane pump is assembled from components that have these dimensional tolerances, Although the centers of the rotor 6 and cam ring 7 tend to shift due to synergistic dimensional tolerances, when the pin holes 1a and 7b are formed in the radial direction of the housing 1 and cam ring 7 as in the past, the positioning pin 35 is This is because it is difficult to adjust the center of the rotor 6 and cam ring 7 using the cam ring.

(2) The deviation between the rotor 6 and the cam ring 7 can be determined by performing so-called selective assembly in which the combination of each component is selected and assembled while measuring the gap between the outer circumference of the rotor 6 and the inner circumferential cam surface 7a of the cam ring 7. Although this problem can be solved to some extent by using selective assembly, the workability of selective assembly is poor.

(3) The tension of a belt (not shown) is applied to the drive shaft 4 via the pulley 32, and since there is a bearing clearance between the drive shaft 4 and the bearings 2 and 3, the drive shaft 4 The roller 6 attached to one end of the drive shaft 4 is eccentric in the tension direction, and the rotor 6 and cam ring 7 are displaced.

(4) The problem mentioned in item (3) above can be solved by making the cam ring 7 eccentric in the direction of the belt tension in advance in anticipation of eccentricity due to the tension of the belt, but in the selective assembly as described above, It is very troublesome to make the cam ring 7 eccentric in the direction of belt tension in advance.
Assembly man-hours increase significantly.

Furthermore, the tension direction may vary depending on the vehicle model, and changing the eccentric direction for each applicable vehicle model confuses the assembly worker.

The present invention has been made for the purpose of providing a centering mechanism that can eliminate the above-mentioned conventional drawbacks. While providing
A substantially semicircular axial groove is provided on the inner periphery of the housing that accommodates the cam ring, corresponding to the axial groove provided in the cam ring, and a substantially circular groove formed by these corresponding axial grooves is provided. A centering mechanism is constituted by a positioning pin insertion hole and a positioning pin that is inserted into the positioning pin insertion hole to prevent relative rotation between the cam ring and the housing, and to align the center positions of the cam ring and the housing by its diameter. There is a particular thing.

Next, the present invention will be explained based on the drawings from FIG. 5 onwards. Note that parts that are the same as those in the prior art are designated by the same reference numerals and redundant explanations will be omitted.

In the figure, 36 and 36' are semicircular axial grooves formed at two axially symmetrical locations on the outer circumference of the cam ring 7;
Reference numerals 37 and 37' denote semicircular axial grooves formed on the inner periphery of the housing 1 to correspond to the axial grooves 36 and 36' provided in the cam ring 7, and these two pairs of corresponding axial grooves 36, 37, 36', 3
7' provides two circular positioning pin insertion holes 3.
8,38' are formed.

39, 39' are inserted into the positioning pin insertion holes 38, 38', and the cam ring 7 is inserted into the positioning pin insertion holes 38, 38'.
This is a positioning pin that prevents relative rotation between the cam ring 7 and the housing 1, and also centers the cam ring 7 and the housing 1 based on its diameter.

The positioning pin insertion holes 38, 38'
and the positioning pins 39, 39' constitute the centering mechanism of the present invention, and these positioning pin insertion holes 38, 3
8' and positioning pins 39, 39', the cam ring 7 is fixed to the housing 1, that is, relative rotation is prevented, and the fixed position is adjusted, that is, the center alignment of the cam ring and the housing is performed.

That is, when the cam ring 7 is inserted into the annular recess 5 of the housing 1 to fix the cam ring 7, the inner circumferential cam surface 7a of the cam ring 7 will move in the direction of the line a of the positioning pin insertion holes 38, 38'. It was discovered that the cam ring was slightly eccentric, and if it was fixed to the housing 1 as it was, the clearance between the rotor 6 and the cam ring 7 near the positioning pin insertion hole 38 would increase, and conversely the positioning pin insertion hole 3 would be slightly eccentric.
If the clearance between the rotor 6 and the cam ring 7 near 8' decreases, and there is a risk that the rotor 6 will come into contact with the cam ring 7 and cause different normal wear, etc., depending on the amount of eccentricity of the cam ring 7, Then, if a positioning pin 39 having a diameter larger than the hole of the positioning pin insertion hole 38 is selected from a large number of pins prepared in advance, and the pin 39 is inserted into the positioning pin insertion hole 38, the cam ring 7 moves slightly in the direction opposite to the direction of the line segment a, and is fixed to the housing 1 with the center of the rotor 6 and the center of the content cam surface 7a aligned. Note that the other positioning pin insertion hole 38' is provided with the conventional
A positioning pin 39' having a diameter matching the diameter of the hole 38' may be inserted.

According to the present invention, the following effects are achieved.

(1) Correcting the deviation of the rotor and center and the center of the cam ring during assembly, which is a simple task of selecting the diameter of the positioning pin and inserting the pin into the positioning pin insertion hole, and correctly aligning the centers of the rotor and the cam ring. It can be adjusted as desired, making selection and assembly easier.

(2) When driving the rotor with a belt suspended from the rotor's drive shaft, experimentally determine the direction of deflection of the rotor when belt tension is applied.
If the configuration is configured so that this direction matches the line segment direction connecting the two positioning pin insertion holes, it is easy to slightly move the cam ring in anticipation of rotor deviation due to belt tension by selecting the diameter of the positioning pin. can be done.

[Brief explanation of the drawing]

Fig. 1 is a sectional view taken along the - line in Fig. 2 showing a conventional vane pump, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a sectional view taken along the - line in Fig. FIG. 5 is a partially cutaway sectional view showing the cam ring fixing structure, FIG. 5 is a view similar to FIG. 2 of the vane pump of the present invention, and FIG. 6 is a sectional view taken along the line -- in FIG. DESCRIPTION OF SYMBOLS 1... Housing, 5... Annular recess, 6... Rotor, 7... Cam ring, 8... Vane, 36,
36', 37, 37'...Axial groove, 38, 38'
...Positioning pin insertion hole, 39, 39'...Positioning pin.

Claims (1)

[Claims] 1 Approximately semicircular axial grooves are provided at axially symmetrical positions on the outer circumference of the cam ring, while approximately semicircular axial grooves are provided on the inner circumference of the housing that accommodates the cam ring, corresponding to the axial grooves provided in the cam ring. axial grooves are provided, and approximately circular positioning pin insertion holes formed by these corresponding axial grooves are inserted into these positioning pin insertion holes to prevent relative rotation between the cam ring and the housing, and the diameter thereof is A centering mechanism for a vane pump, comprising a positioning pin for aligning the center positions of the cam ring and the housing.