JPS61149591A - Tandem type vane pump - Google Patents

Abstract

PURPOSE:To make it possible for at least one cylinder of a tandem type vane pump always to operate by providing a shaft to couple a main rotor with subrotor with a cutting section for separating the above rotors when the subrotor is subjected to an overload more than a specified value. CONSTITUTION:One cylinder 12 of the tandem type vane pump is coupled with a power steering device 27 for steering front wheels, and its other cylinder 13 also with a device 28 for steering rear wheels. The cylinders 12 for steering the front wheels accommodates a main rotor 2, and the cylinder 13 for steering the rear wheels also a subrotor 3, in addition both rotors 2, 3 are coupled through a main shaft 4. The main shaft 4 between both rotors has a part being smaller in diameter than the other part, and this part works as a cutting section to separate coupling between both rotors when the subrotor is subjected to an overload. Consequently, even if such an abnormal state as the subrotor is stopped would happen, only the main rotor for steering the front wheels can be continuously driven.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a tandem vane pump used in front and rear wheel power steering vehicles.

2. Description of the Related Art For example, in a vehicle with a front and rear wheel power steering system, the steering forces of the front and rear wheels are different from each other, so two hydraulic power sources corresponding to the steering forces are required. Therefore, in this type of vehicle, a tandem type vane pump as shown in FIG. 6, for example, is generally used. This vane pump is
A main rotor 2 and a sub-rotor 3, each of which is equipped with a number of vents so as to be retractable in a substantially radial direction, are mounted on a single drive shaft 4 via tin fin joints 5 and 6,
Housing with openings at both ends 7. Cover plates 8.
The main rotor 2 and the sub-rotor 3 are housed inside the main cam ring ratio and the sub-cam ring 13 closed at 10 and 11 (9 and 2 side plates), and the main rotor 2 and the sub-rotor 3 are housed and arranged, respectively. Working chambers 14, 14, . . . whose volumes increase and decrease are formed between adjacent vanes. 1jfr6, reference numerals 15 and 15 denote springs 17 stretched in high pressure chambers 16 and 16 to which discharged oil discharged from the respective working chambers 14 and 14, . . . are guided.

Reference numeral 17 denotes a seal ring for sealing the high pressure chambers 16 , 16 , is, 1 srx. Out of the oil discharged into the high pressure chambers 16 , 16 , excess oil is removed from the hydraulic oil suction holes 19 , 1
9 (A series of low-pressure passages are applied, and a flow rate control valve that returns to 20 and controls the amount of discharged oil discharged from a discharge hole (not shown) at a constant level, 21tff, one of the housings 6 and the drive shaft 4; A shaft seal, η,0, is a bearing that rotatably supports the drive shaft 4.

In this simple configuration, when the drive shaft 4 is driven to rotate and the main rotor 2 and sub-rotor 3 are rotated (b), the hydraulic oil flows through the suction holes 19, 19. It is introduced into each working chamber 14 through a 20° low pressure passage and suction port (not shown), and then the main rotor 2 and sub rotor 3
Pressure is applied due to the change in volume within each working chamber 14 due to the rotation of the work chambers 14. Therefore, the hydraulic oil pressurized in each of the working chambers 14 . Hyperbaric chamber 16, 1
6 and high pressure passages 25, 25 to the flow rate control valve chamber 26.
, 26, and the discharge flow rate is controlled to be constant by the flow rate control valves 18, 18 in the valve chambers 26, 26.

In this way, each C is separate and independent; among the discharged oil whose flow rate is controlled, the discharged oil discharged from the main rotor 2111 is supplied to the power steering device F27 for front wheel steering, and the other is discharged from the sub-rotor 3 side. The discharged oil is supplied to a power steering device for steering the rear wheels.

Problems to be Solved by the Invention By the way, in the conventional tandem vane pump having this L-shaped configuration, when a seizure phenomenon occurs in the sub-rotor 31m1 and the suction rotor 3ζ is subjected to an overload exceeding a predetermined value, , the drive shaft 4 becomes unrotatable. Then,
Both the sub rotor 3 and the main rotor 2 are rotationally driven by a single drive shaft 4 (:), so even if the main rotor 2 is not overloaded more than a predetermined amount, the main rotor 2 will also rotate at the same time. When this difficult situation occurs, the main rotor 2 becomes unable to rotate, and the supply of hydraulic oil to the power steering device for front wheel steering stops, making it impossible to assist front wheel steering. There were problems such as unstable steering.

Means for Solving the Problems In order to solve the above conventional problems, the present invention provides the following:
A cutting part is provided between the main rotor and the sub-rotor to separate the main rotor and the sub-rotor and drive only the main rotor to rotate when an overload of a predetermined level or higher is applied to the sub-rotor.

Function: The present invention, which has this L-shaped configuration, is configured such that when the main rotor and the sub-rotor are rotated by a single drive shaft and an overload of more than a predetermined value is applied to the sub-rotor, the main rotor and the sub-rotor are The main rotor is separated by a cutting portion provided between the main rotor and the main rotor.

Example Embodiments of the present invention will be described below based on the drawings.

Note that the same reference numerals are given to the same components as in the conventional example.

FIG. 1 is a sectional view showing an embodiment of a tandem vane pump according to the present invention.

I! In the construction shown in Fig. 1, a main rotor 2 and three sub-rotors, each having a plurality of vents attached so as to be retractable in an approximately radial direction, are connected to a single drive shaft 4 via a spline joint 59.6. The main cam ring 12 and the sub cam ring 13 are installed inside the main rotor 2 and the sub rotor 3. D. It is closed by the housing 9 and the side plate IO, and the openings at both ends of the sub cam ring 13 are closed by the cover grate 7 and the side grate 11. Adjacent vanes of the plurality of vents... Working chambers 14, 14, .

The hydraulic oil introduced into the working chambers 14 . . . as the main rotor 2 and sub-rotor 3 rotate.

14... Due to the change in volume of the discharge passages 24, 24,
Through the high pressure chambers 16, 16 and the high pressure passage device, 25, the flow rate control valve chamber 26°26 (=discharged into the valve chambers 26, 2
After the flow rate is controlled by flow control valves 18 and 18 in 6, it is supplied to a power steering device n for steering the front wheels and a power steering device 28 for steering the rear wheels.

On the other hand, between the main rotor 2 and the sub-rotor 3 (specifically, the tin line coupling part 5 on the main rotor 2 side and the tin line coupling part 6 on the sub-rotor 3 side of the drive shaft 4),
) between these main rotor 2 and sub rotor 3
A small-diameter part is formed as a cutting part that disconnects the main rotor 2 when an overload of a predetermined value or more is applied to the sub-rotor 3 and rotates only the main rotor 2. The other outer diameter area of the drive shaft 4 is also formed to have a small diameter on the outer diameter of this small diameter part, and if an overload of more than a predetermined value is applied to the sub rotor 3, this small diameter part will be twisted and the main Only the rotor 2 is driven to rotate.

If this tandem vane pump with this L-shaped configuration is constructed, if a seizure phenomenon occurs on the sub-rotor 3 side and an overload exceeding a predetermined level is applied to the sub-rotor 3,
Excessive torque also occurs on the drive shaft 4, but since the small diameter portion 29 is formed between the spline joint 5 on the main rotor 2 side and the tin line joint 6 on the sub rotor 3 side,
This small-diameter part is twisted, so that the rotational force of the drive shaft 4 is transmitted only to the main rotor 2, and only the main rotor 2 is rotationally driven. Therefore, since the rotation of the main rotor 2 continues, the hydraulic oil continues to be supplied to the power steering device a for front wheel steering, and the front wheel steering can be continuously assisted.

In addition, in the above embodiment, the small diameter 8 (1
For example, as shown in FIG. 2, the spline joint 5 of the main rotor 2I1M
The fitting length t1 of the spline 2-in that makes up the sub-rotor 3tl is also the fitting length t of the spline making up the spline joint 6 of the sub-rotor 3tl [! It is also possible to form the sub-rotor 3m short and form the cutting part at the spline joint part 6 of the sub-rotor 3m. When constructed in this manner, the mechanical strength of the spline joint 5 on the main rotor 2 side also increases with respect to the sub-rotor 3g1.
It is possible to weaken the mechanical strength of the spline joint 6 of l.

Therefore, as in the case of the embodiment described above, when an overload of a predetermined level or more is applied to the sub-rotor 3, the spline joint 6 on the sub-rotor 3 side is broken and separated, and only the main rotor 2 continues to be driven to rotate. I can do it.

Also, unlike the case of the above embodiment, the main rotor is 2ga
The number of peaks of splines constituting the spline joint 5 of the sub-rotor 3111 is also the same as that of the spline joint 6 of the sub-rotor 3111.
Even if the number of peaks of the tin twin constituting the structure is reduced, the same functions and effects as in the embodiment described above can be obtained.

Furthermore, unlike the case of the embodiment shown in FIG. 1,
As shown in FIG. 3, 29 through holes penetrating the drive shaft 4 in the diametrical direction may be formed as cutting portions, or a dovetail groove may be formed in the drive shaft 4 as shown in FIG. 29B, or even if the drive shaft 4 is divided into two halves and connected by a key member 29C as shown in FIG. It will be done.

Further, in each of the above-mentioned embodiments, an example was explained in which spline joints 5 and 6 were used as the joints, but the present invention is not limited to this, and the present invention can also be applied to those using serration joints.

Effects of the Invention As is clear from the above explanation, if this invention is implemented, a cutting portion is provided between the main rotor and the sub-rotor, so that
When an overload exceeding a predetermined level is applied to the sub-rotor, the cutting section disconnects and only the main rotor can continue to be rotated. Therefore, for example, hydraulic oil can be continuously supplied to a power steering device for steering the front wheels, etc. Effects such as being able to perform

[Brief explanation of drawings]

Fig. IIi is a sectional view showing one embodiment of the tandem vane pump according to the present invention, Fig. Wcz is a sectional view showing another embodiment of the invention, and Figs. The main part plan view showing the embodiment, Figure @6 is a sectional view showing a conventional tandem vane pump. DESCRIPTION OF SYMBOLS 1... Vane, 2... Main rotor, 3... Sub-rotor, 4... Drive shaft, 5, 6... Spline joint (joint part), 12... Main cam ring, 13...
・Sapcam ring, 14...Working chamber, Vessel...Small diameter part (cutting part), 4 pieces...Through hole (cutting l1l), 29B
...Dovetail groove part (cutting part), 29C...key part. 2 people outside

Claims (3)

[Claims] (1) A main rotor and a sub-rotor, each of which has a plurality of vanes that can be retracted and retracted in a substantially radial direction, are mounted on a single drive shaft via a coupling part, and inside the main cam ring and sub-cam ring with both end openings closed. In the tandem vane pump, the main rotor and the sub-rotor are respectively accommodated and a working chamber whose volume increases and decreases is formed between adjacent vanes of the plurality of vanes, wherein these are arranged between the main rotor and the sub-rotor. A tandem vane pump characterized in that a cutting portion is provided that disconnects the sub-rotor when an overload of a predetermined value or more is applied to the sub-rotor and rotates only the main rotor. (2) The tandem vane pump according to claim 1, wherein the cutting portion is a small diameter portion formed between a connecting portion on the main rotor side and a connecting portion on the sub-rotor side of the drive shaft. . (3) The tandem vane pump according to claim 1, wherein the cutting portion is a connecting portion on the sub-rotor side that is formed to have a mechanical strength weaker than the mechanical strength of the connecting portion on the main rotor side.