JPS637278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil pump that includes two sets of pumps and a pair of spool valves that selectively supply pressurized fluid from both pumps to fluid equipment.

For example, in a power steering device mounted on an automobile to reduce the steering force of a driver, a pump that is a source of oil pressure generation is usually rotationally driven by the engine of the automobile. The amount of hydraulic oil discharged from this pump increases or decreases in proportion to the engine speed. Therefore, such a pump is required to have a capacity that can supply a sufficient flow rate to the operation of fluid equipment such as the power steering device even when the engine speed is low, that is, when the pump discharge amount is small. be done.

However, if you set the pump capacity like this,
In the high rotation range of the engine, an unnecessarily large amount of flow is supplied to the power steering device, resulting in a lot of waste.
In addition, the horsepower consumption of the engine for driving the pump increases, which is not preferable from the viewpoint of energy saving.
In particular, in recent years, there has been a call for improved fuel efficiency of automobile engines, and it is desired to minimize the horsepower consumption of the pump for the power steering device described above.

For this reason, devices have been proposed that are configured by combining two pumps with small capacities and a control section equipped with a flow path switching mechanism that operates according to the discharge amount of these pumps. With this device, when the discharge volume of each pump is small, it is possible to combine them and supply them to ensure the operational reliability of the fluid equipment, and when the discharge volume of each pump becomes large, one pump can be supplied. One of the pumps is used for hydraulic pressure supply, and the other is connected to the tank side for no-load status.This has the advantage of minimizing the horsepower required to drive the pump and reducing horsepower consumption. be.

However, in such conventional devices, 2
A common configuration is to use a flow control valve to control the pump supply amount at a constant level to switch the flow path between the pump and the fluid equipment. Not only is it troublesome to process, but there are also problems such as a tendency to adversely affect fluid supply during valve operation.

In other words, this type of flow control valve is generally composed of a spool valve, and in order to provide the flow control function and flow path switching function, the valve length is long, and there are many passages and the corresponding spool outer circumference. This requires a ring-shaped groove, etc., which is not preferable in terms of workability. In addition, during operation, the discharge flow rate tends to be disturbed or discontinuous, making it unstable and lacking in operational reliability.Furthermore, pressure is applied in different directions to the long spool, causing sliding failures.
It is also unfavorable from the viewpoint of durability.

In addition, this type of device is generally integrated with two sets of pumps in one pump housing, and the above-mentioned structural issues such as pump length have a large impact on pump design and manufacturing. It is also a problem from a cost perspective. In particular, in recent years, there has been a demand for pumps that are small, lightweight, and low cost, and it is desired to solve the above-mentioned problems.

The present invention has been made in view of the above circumstances, and includes a flow control valve that controls a control unit that selectively supplies pressure fluid from two sets of pumps to a fluid equipment side to keep the supply amount of pressure fluid below a predetermined value. and a pair of spool valves that operate as flow path switching valves that switch the flow path from each pump in conjunction with this, and these pair of spool valves are arranged in the axial direction around the pump storage space provided in the pump body. Manufacture and assembly are easy due to the simple structure of arranging the pumps in parallel and connecting the fluid passages using cast holes integrally formed in the pump body or drilled holes that can be formed by simple hole machining. To provide an oil pump that can be easily manufactured, has a low manufacturing cost, and can satisfy the demands for miniaturization and weight reduction.

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

1 to 4 show an embodiment of an oil pump according to the present invention, and in this embodiment, a case where the oil pump is applied to a power steering system for an automobile will be explained.

In these figures, reference numerals 1 and 2 are a front body and a rear body that constitute a pump body, and inside thereof there are first and second pumps 3 and 4 having different discharge capacities, and discharge from both pumps 3 and 4. First and second spool valves 5 and 6 constituting a control unit that controls the supply amount of pressure oil are integrally incorporated, and a fluid passageway is formed to appropriately connect these spool valves.

That is, as shown in FIGS. 2 and 3, a bottomed pump storage space 7 is formed in the center of the rear body 2 and opens toward the front body 1. First and second pumps 3, 4 are arranged side by side in the axial direction. These pumps 3 and 4 are rotationally driven by a common drive shaft 8 inserted through the central hole 1a of the front body 1, and perform pumping operations respectively.

Note that these first and second pumps 3 and 4 have a conventionally well-known vane pump configuration, and to briefly explain this, the first pump 3 is connected to the drive shaft 8.
The pump includes a rotor 9 having a plurality of vanes 9a fixed thereon, a cam ring 10, a side plate 11, a pressure plate 12, etc., and is disposed within a large diameter portion 7a formed on the opening side of the pump storage space 7. Ru. In this case, the side plate 11
is locked by a step 7b provided in the axial center of the storage space 7, and is connected to a second pump 4, which will be described later.
It also serves as a side plate. Further, the pressure plate 12 is disposed on the opening side of the storage space 7, and forms a pressure chamber 13 on the pump discharge side between it and the front body 1 that closes this opening.

On the other hand, the second pump 4 is also fixed on the drive shaft 8 and includes a rotor 14 having a plurality of vanes 14a, a cam ring 15, a pressure plate 16, etc., and the storage space 7 is formed on the bottom side. It is disposed within the small diameter portion 7c.

A spring 17 is disposed between the pressure plate 16 and the bottom of the storage space 7, and this part serves as the pressure chamber 1 on the discharge side of the second pump 4.
It has become 8. Although a spring 19 is also provided in the discharge side pressure chamber 13 of the first pump 3, these springs 17 and 19 are not necessarily necessary.

Also, the cam rings 10, 15 of both pumps 3, 4
Pressure chambers 20 and 21 on the pump suction side are formed on the outer periphery of the pump, and these pressure chambers 20 and 21 communicate with each other through a hole 22 formed in the side plate 11. And these suction side pressure chambers 20, 21
As is clear from Fig. 5, the rear body 2
Hydraulic oil is introduced from an oil tank (not shown) through an inlet passage 23 formed on the side of the spool valve and a passage 24 communicating with a valve hole of one of the spool valves, which will be described later. Furthermore, in the figure, 25 is a rod for positioning each of the above-mentioned pump components;
27 is a bearing that pivotally supports the drive shaft 8 within the front body 1, and an oil seal that prevents oil leakage to the outside.

In this case, according to the configuration described above, if the capacity of the first pump 3 is set smaller than that of the second pump 4, the energy saving effect can be further improved. Furthermore, it is desirable to arrange the components of both pumps 3 and 4 in parallel with different phases in the rotational direction, and to shift the phase of the pulsation of the discharge pressure from each pump so that smooth pumping action can be obtained. .

Further, the rear body 2 is connected to the pressure oil discharged from the first and second pumps 3 and 4 through an outlet passage 30 that opens to the side of the rear end of the rear body 2 to supply fluid to a power steering device or the like. A rotation speed sensing type control section consisting of a pair of spool valves 5, 6 and a fluid passage for selectively supplying equipment to the equipment is appropriately arranged around the pump housing space 7.

That is, in the figure, reference numerals 31 and 32 indicate a pair of valve holes arranged in parallel on the upper side of the rear body 2 so as to be close to each other. It opens at the joint surface on the body 1 side and is formed so that the axial direction is parallel to the pump storage space 7. These valve holes 31 and 32 are closed together with the pump storage space 7 by the front body 1 in a liquid-tight manner.

Further, reference numeral 33 denotes a passage hole bored from the rear end side of the rear body 2 so as to be located between the two valve holes 31 and 32, and the axis thereof is located between the two valve holes 31 and 32.
It is arranged so as to be located in substantially the same plane as the axis line of 32. As is clear from FIG. 6, the opening of this passage hole 33 is sealed by a blind plug 34, and a passage 35 opening from below in the vicinity of this opening connects the second pump 4. It communicates with the discharge side pressure chamber 18 of. Furthermore, the other end of this passage hole 33 extends to approximately the center of the rear body 2 in the axial direction, and is connected to a side passage hole 36 that is bored from the side of the rear body 2 through the one valve hole 31. It is connected.

Therefore, with such a configuration, the pressure oil discharged from the second pump 4 is guided to the center of the valve hole 31 via the passage 35, passage hole 33, and side passage hole 36 described above. You will be killed. In addition,
37 is a blind plug that seals the opening of this passage hole 36.

On the other hand, a common passage hole 38 is arranged on the side of the rear body 2 and is bored from the rear end side of the rear body 2 in parallel with the pump storage space 7, and a part of the common passage hole 38 opens into the outlet passage 30. ing. Furthermore, 39
is a ball that closes the opening of the common passage hole 38.

The pump storage space 7, the pair of valve holes 31 and 32, and the common passage hole 38 correspond to the discharge side pressure chamber 13 of the first pump 3 formed near the opening of the pump storage space 7. A rectangular passage groove 4 formed in the rear body 2 as shown in FIG.
0, 41; and 42, respectively.

Further, within the first valve hole 31, there is a passage hole 36 through which pressure oil from the second pump 4 is guided.
On the rear end side, there is a pump storage space 7 at a position corresponding to the suction side pressure chamber 21 of the second pump 4.
A return passage groove 43 communicating with is formed. On the other hand, on the second valve hole 32 side, a passage 24 that communicates with the inlet passage 23 from the side of the rear body 2 described above opens so as to be located on the front end side of the central part in the axial direction. 24 is connected to the pump storage space 7 at a position corresponding to the suction side pressure chamber 20 of the first pump 1, as shown in FIG. Note that the common passage hole 38 and the passage groove 4
2 is an orifice 44 for detecting the flow rate supplied to the fluid equipment and operating spool valves 5 and 6, which will be described later as flow path switching valves and flow rate control valves.

Now, in such a configuration, in the valve holes 31 and 32, the spools 45 and 46 constituting the first and second spool valves 5 and 6, which operate as a flow path switching valve and a flow rate control valve, respectively.
These spools 45 and 46 are operated in response to the fluid pressure difference generated before and after the orifice 44 provided in the middle of the common passage hole 38 to control the amount of fluid supplied to the fluid equipment. Maintain the value below the specified value.

That is, the spool 45 installed in the first valve hole 31 is always located at the front end on the front body 1 side due to the spring 47 installed in the bottom side of the valve hole 31. In this state, the check valve 48 provided at the front end of the spool 45 closes the through hole 45 in the spool 45.
a and an annular groove 45b on its outer periphery to the passage holes 33, 36 from the second pump 4, and these passage holes 33, 36 are separated from the return passage groove 43 by a land portion 45c. There is. Therefore, the check valve 48 is opened by the pressure oil from the second pump 4, and the pressure oil is transferred to the discharge side pressure of the first pump 3 through the passage groove 40 that opens to the front end of the valve hole 31. It is led into the chamber 13 and joined with the discharge pressure oil of the first pump 3. When the spool 45 moves toward the rear end, the passage hole 36 and the return passage groove 43 are connected with each other as the spool 45 moves toward the rear end, so that the pressure oil from the second pump 4 is transferred to the pump suction side. It is configured to allow the flow to flow back, and acts as a flow path switching valve. Note that this first spool valve 5
Then, the discharge side pressure chamber 1 of the first pump 3 is connected to the high pressure chamber 49 on the front end side of the spool 45 via the passage groove 40.
The hydraulic pressure on the 3rd side, that is, the upstream side of the orifice 44, is
Further, hydraulic pressure downstream of the orifice 44 is guided to the low pressure chamber 50 on the rear end side by a low pressure chamber of a second spool valve 6, a small diameter passage hole, etc., which will be described later.

On the other hand, the spool 46 incorporated into the second valve hole 32 constitutes a conventionally known flow control valve. That is, the hydraulic pressure on the discharge side pressure chamber 13 side, that is, on the upstream side of the flow sensing orifice 44, is introduced into the high pressure chamber 51 formed at the front end of the valve hole 32 by the spool 46 via the passage groove 41. On the other hand, hydraulic pressure downstream of the orifice 44 is guided to a low pressure chamber 52 on the rear end side through a passage 53 communicating with the outlet passage 30. The spool 46 is normally positioned on the front end side of the valve hole 32 by a spring 54 disposed in the low pressure chamber 52, and at this time, an annular groove 46a provided on the outer periphery of the central portion thereof is connected to the inlet passage 23. The discharge side pressure chamber 13 and the passage 24 are separated from each other. On the other hand, when the flow rate of the pressure oil sent out from the discharge side pressure chamber 13 increases and exceeds a predetermined amount, the spool 46 is moved to the valve hole 3 due to the differential pressure generated above the orifice 44 and on the downstream side.
2, connects the discharge side pressure chamber 13 and the passage 24 as appropriate, and returns a predetermined amount or more of pressure oil to the pump suction side.

The first and second spool valves 5 and 6, which operate as described above, are associated with each other in the following manner and are configured to operate in conjunction with each other.

That is, as is clear from FIGS. 1 and 3, the upper part of the passage hole 33 formed between the pair of valve holes 31 and 32 has an axis parallel to the upper part of the passage hole 33 formed between the pair of valve holes 31 and 32, from the rear end of the rear body 2. A small diameter passage hole 55 is bored, and the opening side of the small diameter passage hole 55 communicates with the first valve hole 31 through a small hole 56 bored diagonally from the upper end of the rear body 2, while the bottom side Similarly, the second valve hole 3 is formed by a small hole 57 diagonally bored from the upper end of the rear body 2.
It is connected to 2. Of course, the openings of the small diameter passage hole 55 and the pair of small holes 56 and 57 are formed by the ball 55.
a; Sealed by 56a and 57a. Further, the small hole 56 is located in the low pressure chamber 5 on the right side of the spool 45.
It opens in 0.

On the other hand, in the spool 46 incorporated in the second valve hole 32, the land portion 46b forming the low pressure chamber 52 normally opens the small hole 57 to the low pressure chamber 52 side, and during operation. Small hole 57
It is configured to pass over the opening of the tank and communicate with the passage 24 on the tank side via the annular groove 46a.

According to such a configuration, when the rotation speed is small and the discharge amount from each pump 3, 4 is small, the pressure oil from the second pump 4 opens the check valve 48 and flows to the first pump 3. It is supplied by combining with pressure oil from. Further, when the combined supply amount exceeds a predetermined amount, the second spool valve 6, which functions as a normal flow rate control valve, is activated and returns the excess flow rate to the tank side, while the land portion 46b of the spool 46 is activated. The small diameter 57 is switched from pump discharge pressure to tank pressure. Then, the first spool valve 5 moves to the right, and the annular groove 45b,
The through groove 45a is connected to the return passage groove 43, and the second
Pressure oil from the pump 4 is separated from the main supply passage side and returned to the tank side via the return passage groove 43.
That is, according to such a configuration, in the high rotation range of the pump where the supply amount is guaranteed only by the discharge amount from the first pump 3, the second pump 4 is disconnected and placed in an unloaded state, thereby reducing consumption. Operates to reduce horsepower.

Note that, as shown in FIGS. 3 and 7, the passage 53 that communicates the outlet passage 30 with the low pressure chamber 52 is formed by a hole bored from outside the body forming the outlet passage 30. The structure is such that it can be easily processed. in this case,
In the figure, 53a is an orifice for preventing oscillation of the spool 46, and 53b is a ball that seals the opening of the passage 53. Furthermore, a well-known relief valve 58 is provided within the spool 46.

Further, on both sides of the front body 1, fourth
As is clear from the figure, a pair of mounting brackets 59a and 59b are provided, and the front body 1 and rear body 2 are integrally connected by four bolts 60. In addition, the symbol 6 in the figure
1 is an outlet member for connection to the fluid equipment side, and 62 is an inlet member connected to the oil tank side, which are attached to the outside of the rear body 2 in correspondence with the aforementioned outlet passage 30 and inlet passage 23, respectively.

In the oil pump configured as described above, the pair of spool valves 5 and 6, which operate as flow path switching valves and flow rate control valves, have their axes aligned around the pump storage space 7 formed at the center of the pump body. The valve holes 31 and 32 are arranged in parallel and close to each other, and the pump storage space 7 is connected to the valve holes 31 and 32.
The passage that connects the pump body and the passage that connects to the fluid outlet and inlet are constructed of cast holes that are formed integrally with the pump body and drilled holes that are formed by simple hole machining, making the entire structure simple and compact. It has the advantage that it has a simple pump configuration, is easy to manufacture and assemble, and is inexpensive to manufacture.

In particular, as shown in the embodiment described above, the pump storage space 7 and the pair of valve holes 31, 32 are opened at the joint surface of the divided rear body 2 on the front body 1 side, and each pump is opened from this opening side. Since it is configured to incorporate valve component parts such as component parts, spools, and springs, it is excellent in terms of ease of assembly, and is also advantageous in terms of sealing performance of each opening.

Further, the opening sides of the respective valve holes 31 and 32 are defined as high pressure chambers 49 and 51, passage grooves 40 and 41 are formed therein, and a discharge side pressure chamber of the first pump 3 is formed on the side of the pump housing space 7. 13, and further communicates this pressure chamber 13 with the common passage hole 38 side on the output side via the passage groove 42, whereby the discharge side pressure chamber 13 of the first pump 3 is connected to the second pump 3. Since it is used as the main supply passage including the merging section where the pressure oil from 4 is merged, the pump structure is simpler and it is advantageous in terms of manufacturing.

As explained above, according to the oil pump according to the present invention, it is possible to rationally supply pressure fluid to two sets of pumps and pressure fluid equipment from these two pumps, reduce pump horsepower consumption, and save energy. A flow rate sensing type control unit with a pair of spool valves that can be connected to the pump storage space, a pair of valve holes formed around the space so that their axes are parallel, and a cast hole or simple hole machining that communicates these. Since it is integrated into one pump body using the drilled holes formed, the overall structure is simple, manufacturing and assembly are easy, the manufacturing cost is low, and it is also smaller. It also has various excellent effects such as being able to satisfy the demand for weight reduction.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of an oil pump according to the present invention, FIG. 2 is a vertical cross-sectional view, and FIG.
The figures are cross-sectional views taken along the - line in Figures 1 and 2, and Figure 4.
5 is a detailed view of the vicinity of the inlet passage, FIG. 6 is a detailed view of the passage hole formed between the valve holes, and FIG. 7 is a detailed view of the vicinity of the outlet passage. 1...Front body, 2...Rear body, 3
...First pump, 4...Second pump, 5...
First spool valve, 6...Second spool valve, 7...Pump storage space, 8...Pump drive shaft, 30...Outlet passage, 31...First valve hole, 32...Second spool valve Valve hole, 33...passage hole,
36... Side passage hole, 40, 41... Passage groove, 4
5, 46...Spool, 48...Check valve, 55...
...Small diameter passage hole, 56, 57...Small hole.

Claims (1)

[Claims] 1 A pump body that integrally incorporates two sets of pumps that discharge pressure fluid separately, and a pair of spool valves that switch the flow paths of the pressure fluid from these pumps and control the amount of supply to the fluid equipment. In the oil pump, the pump body includes a pump storage space in which the two sets of pumps are arranged side by side on a common drive shaft, and a space around the pump storage space so that the axial direction is parallel to the pump storage space. valve holes of the pair of spool valves formed close to each other, and one end side of both valve holes formed between these valve holes and the pump storage space to the discharge side pressure chamber of the one pump. and a passage hole located between the two valve holes to which pressure fluid from the other pump is guided and communicating with the one valve hole via a side passage hole, The pair of valve holes are formed by a small diameter passage hole formed in the upper part so that the axial direction is parallel to the passage hole, and a pair of small holes bored from the small diameter passage hole to each valve hole. An oil pump characterized by being connected.