JPS59101593A - Pump for power steering device - Google Patents

Abstract

PURPOSE:To reduce number of the parts used, compact the whole construction, facilitate fabrication and to suppress the cost, by supplying the pressure fluid discharged selectively by two pumps, to the power steering device from a high pressure chamber formed in the middle of the two pumps. CONSTITUTION:When a small-capacity pump P1 is driven by a drive shaft 8, the fluid in a reserver tank 56 is taken in the small-capacity pump P1 from a suction pipe 17 to be discharged in the form of pressure fluid, which then flows into a high pressure chamber 18 formed between two pressure plates 6, 12. A large-capacity pump P2 is driven by a drive shaft 9 when an electromagnetic clutch 2 is put in engagement, and the fluid discharged therefrom converges at said high pressure chamber 18 with the fluid discharged by the small-capacity pump P1. While the car is running at extra-low speed, both pumps P1, P2 are driven, and the combined flow from two pumps is fed to the power steering device PS from a feed port 39. When the car speed increases thereafter, the large-capacity pump P2 stops rotating, while the small-capacity pump P1 is solely driven in continuity.

Description

[Detailed Description of the Invention] This invention relates to a pump device for a power steering device, and its purpose is to reduce the number of parts, make the whole compact, and facilitate assembly. This was done to reduce costs.

As conventionally disclosed in Japanese Unexamined Patent Publication No. 57-38068, it has a first pump that is directly driven by the engine of an automobile, and a second pump that is interlocked with the first pump via a clutch means, A device is known in which the operation of the clutch is controlled according to the operation status of the vehicle and pressure fluid is supplied to the power steering device to assist the steering force, but this conventional device has the following features. It has its drawbacks.

(a) The first pump and the second pump are built into one housing, but in order to supply pressure fluid from both pumps to the power steering device, there is
Since the supply ports provided in the nozzle are formed in each of the two pumps, two supply paths for pressurized fluid from the pump device to the power steering device are formed. The road structure becomes complicated.

(b) Both pumps are held between pressure plates biased by springs, and the pressurized fluid discharged from both pumps is passed through passages provided in the respective pressure plates to the high pressure chamber housing the springs. The high-pressure chambers housing the nozzles and springs are installed in two locations within the nozzle, which increases the size of the pump device itself. Put it away.

The present invention eliminates the drawbacks of the conventional system by forming a high pressure chamber between two pumps and supplying the pressure fluid selectively discharged from both pumps to the power steering device from the high pressure chamber. be.

Next, an embodiment of the present invention shown in the accompanying drawings will be described. Reference numeral 1 denotes a substantially cylindrical pump housing, which has a pump chamber 41 on one side and a bearing mounting portion 4''2 on the other side through a partition wall 40 inside. , rotor 8, cam ring 4 and vane 3
4 and an end plate 5 that closes the opening of the pump chamber.
and a large discharge capacity vane pump P formed by sandwiching the rotor 10, cam ring 11, and vane 85 between the partition wall 40 and the pleat/yaar plate 12. The vane type pump P2 is incorporated and separated. Reference numeral 9 denotes a cylindrical drive shaft for driving the large-capacity pump P2, which is formed through a sealed bearing 48 mounted on the inner circumferential surface of the bearing mounting portion 42 and lubricated with grease, and a central portion of the partition wall. Insertion hole 4
4 is supported by a bearing bushing 45 attached to the inner peripheral surface of the bearing bushing 45. One end of the drive shaft 9 is fitted with a serration into the center hole formed in the rotor 10 of the large-capacity pump described in 11. The drive plate 28 is connected to the drive plate 28 by bolts 32. A labyrinth is completely formed between the flange 46 and the end face of the opening of the bearing mounting part 42, and the bearing mounting part 42
It prevents dust from entering the interior and enhances the sealing effect.

A drive shaft 8 is inserted into the inside of the drive shaft 9, and bearing bushings 47, 48 are provided in the center hole formed in the side plate 6 of the small capacity pump P and on the inner peripheral surface of the drive shaft 9, respectively.
Supported through. One end of the drive shaft 8 is still serrated fitted into the center hole formed in the rotor 3 of the small capacity pump P, and the other end is keyed to the boss 71. Reference numeral 80 designates an excitation coil for the electromagnetic clutch 2, and the coil 30 is fixed to the outer surface of the housing 1 with bolts 38 while being fitted onto the outer circumference of the bearing mounting portion 42. A pulley 25 is formed to cover the electromagnetic clutch 2, and is fixed by a rivet 81 to the side surface of a flange formed on the outer periphery of the boss 71, together with a spring 26 that is integrally fixed to the drive plate 27 of the electromagnetic clutch 2. ,
The rotational force of the pulley 25 is transmitted to the drive shaft 8 and the drive shaft 9 via the electromagnetic clutch 2, respectively.

7 is a retaining ring that prevents the end cover 5 from coming out, 15
1 is a spring that urges the pressure plates 6 and 12 in the direction away from each other and presses them against the rotors 3 and 10, respectively. The inner periphery of the cylindrical portion 12α is molded so that it can slide in a sealing manner with the cylindrical portion 6a integrally formed on the side surface of the sight plate 6.

Next, the effect will be explained. Now, the small capacity pump P1 is
When driven by the drive shaft 8, the fluid in the reservoir tank 56 flows through the suction pipe 1 attached to the housing 1.
7 to the suction port 6 through passages 20, 21 and 22a bored in the peripheral wall of the pump chamber 41 of the housing 1.
3 into the small capacity pump P1. The flow rate of the sucked fluid increases in proportion to the rotational speed of the pump, and is discharged from the discharge port 65 as pressure fluid. A passage 50 communicating with the discharge port is formed in the pressure plate 6, and the discharge fluid flows into the high pressure chamber 18 formed between the pressure plate 6 and another pressure plate 12 through the passage 50. do. Note that the suction pipe 17 and the passage 20 are connected diagonally as shown in FIG. 2 so that fluid can be easily sucked from the pipe 17 to the passage 20, and a return passage 20' to be described later is connected. The fluid flowing back from the passage 20 smoothly joins the fluid flowing through the passage 20, thereby preventing dynamic pressure from being generated at the connection part of the passage, resulting in insufficient suction, cavitation, or noise. ing. 6? 6 is a valve chamber formed by drilling a straight hole in the axial direction in the circumferential wall of the pump chamber 410 and sealing it with a plug 68;
A flow rate control valve 16 is mounted to be movable in the axial direction inside the valve chamber 67, and a return passage 20 and a passage 19 into which the pressure fluid from the high pressure chamber 18 flows are formed on the wall surface of the valve chamber 67. A spring 88 is interposed between one end of the flow rate control valve 16 and the plug 68, and the spring 38 biases the flow rate control valve 16 in one direction (to the right in the figure), thereby opening the return passage. 20' and the passage 19 are blocked off. The pressure fluid that has flowed into the pressure chamber 18 flows into the right side of the flow rate control valve 16 of the valve chamber 67 in the figure through the passage 19, and the flow rate increases, and the fluid pressure at the variable throttle section 69 increases. When the flow rate control valve 16 rises, the flow rate control valve 16 resists the biasing force of the spring 38.
Move to the left in the figure. When the inflow amount of pressure fluid is specified l'
When the flow rate control valve 16 exceeds it, the flow control valve 16 moves further and communicates with the MiJ passage 19 and the return passage 20 at full speed, causing the surplus flow to flow back through the return passage 20.

Therefore, the flow meter supplied to the power steering device 1) S through the passage 52 formed from the throttle 69 to the valve chamber 67 and the supply port 39 indicates that when the pump discharge flow rate increases at a constant tt, the supply flow rate remains constant thereafter. Become. The inner surface of the end of the plug 68 ft1l of the flow rate control outlet valve I6 is l)
l) - A valve 55 is installed, and a passage 58 formed between the passage 52 and the supply port 39 allows the pressure inside the power steering device PS to be transferred to the IJI via the passage 53.
Act on the J-fu valve. The IJ IJ-F valve 55 opens when the pressure inside the power steering system rlps exceeds a predetermined value, and connects the power steering system PS and the return passage 20' through a through hole 72 formed in the flow control valve. The pressure is returned to a predetermined direction, thereby preventing damage to the device due to abnormal pressure rise.

When the electromagnetic winter latch 2 is connected, the large-capacity pump P2 is driven by the drive shaft 9 and sucks the fluid in the reservoir tank 56 from the pipe 17 to the passages 20, 21, 22, . '5
The water is sucked into the pump P2 from the suction port 64 through the suction port 64.

The suction pipe of the large capacity pump P2 and the small capacity pump P1 is common, and as shown in FIG.
The fluid that has flowed in through the passage 20 formed in the housing 1.
It branches into a passage 22α and a passage 22b via the force/reverse passage 21, and the passage 22a communicates with the 1v'-inlet 63 of the small capacity pump P1, and the passage 221I communicates with the suction port 64 of the large capacity pump P2. From the circuit, it is sucked into the respective pump PI + P2. The fluid sucked in from the suction port 64 is discharged as pressure fluid from the discharge port 66, and is discharged into the high pressure chamber 18 through a passage 51 that communicates with the discharge port 66 formed in the pressure plate 12, where it is discharged into the high pressure chamber 18. It joins the discharge fluid from the volumetric pump P1. Reference numeral 18 denotes a check valve installed in the passage 51 formed in the Brella gloss pump 12, and when the large-capacity pump P2 does not rotate and no pressure fluid is discharged, the discharge fluid of the small-capacity pump P is kept at the high pressure. This is to prevent backflow from the chamber 18 into the inside of the dog waste pump P2.

Note that when the small capacity pump P1 and the large capacity pump P2 are driven at the same time, the pressure in the high pressure chamber 1-8 becomes extremely high, and there is concern about the pressure resistance of the small capacity pump that is not provided with a check valve. In the present invention, one small-capacity pump (vane type pump) is used, and since the vane type pump itself has excellent pressure resistance, there is no problem.

In addition, when using a pump with poor pressure resistance such as a trochoid type pump as the small-capacity pump, it is recommended to provide a check valve on the small-capacity pump side for safety.

23 and 24 are train holes, respectively, for draining a portion of the pressure fluid inside the pump chamber 41 to the suction port 64 when the bearing bushes 44, 48 and 47 use a portion of the pressure fluid inside the pump chamber 41 as lubricating oil. It is. Reference numeral 70 denotes an oil seal that prevents the pressure fluid to be drained from leaking to the outside, and prevents the fluid from getting mixed into the bearing 48 that is lubricated with grease, or from oil adhering to the electromagnetic clutch, which may cause problems in torque transmission. Prevents it from becoming a hindrance. The electromagnetic clutch 2 uses a battery 62 as a power source, and responds to electric signals obtained from a vehicle speed detection sensor 59 that generates an electric signal corresponding to the traveling speed of the vehicle and a pressure sensor 60 that generates an electric signal corresponding to the circuit pressure. The connection/disconnection is controlled by the control device 61 so as to operate,
The drive of the large capacity pump P2 is controlled. When the vehicle is stationary or running at an extremely low speed, the vehicle speed detection sensor 59 outputs a signal indicating the state of the vehicle to the control device 61, which excites the excitation coil 30 of the electromagnetic clutch 2 and drives the drive plate 27. and the driven plate 28 are connected.

Therefore, the rotation of the engine is controlled by the drive shaft 8 via the pulley 25.
and 9, small capacity pump P.

and large capacity pump P2 are both driven. Therefore, the combined flow rate of the two pumps is supplied to the power steering system PS.

Next, when the vehicle speed increases, the control device 6 receives the signal from the vehicle speed detection sensor 59 and cuts off the current flowing to the excitation coil 80 of the electromagnetic clutch 2. Separate.

As a result, the rotation of the large capacity pump P2 is stopped, only the small capacity pump P1 is driven, and only the fluid discharged from the small capacity pump P1 is supplied to the power steering device PS.

At this time, due to the function of the check valve 13, the fluid discharged from the small capacity pump P1 does not flow back into the gage pump P2. The circuit pressure sensor 60 is the vehicle speed detection sensor 59
It outputs the signal to the control device 61 independently from and outputs it to the control device 61,
The control device 61 excites the excitation coil 80 of the electromagnetic clutch 2, connects the drive plate 27 and the driven plate 28, drives both the small-capacity pump P1 and the large-capacity pump P2, and connects the two to the power steering device PS. Provides the combined flow rate of two pumps.

According to the present invention, the pressure fluid selectively discharged from the two pumps is introduced into the high pressure chamber formed between the two pumps, and the introduced pressure fluid is supplied to the power steering device. It is only necessary to form a pressure fluid in one place, and the supply path for supplying pressure fluid from the pump device to the power steering device only needs to be provided in the high pressure chamber, so the configuration of the supply path is simplified, and it is possible to install the pressure fluid in the high pressure chamber. Only one spring is required for the pump, and the number of parts is small, making the whole compact. Furthermore, the cylindrical parts integrally formed on the sides of the pressure plates of both pumps are slidably fitted to the sides of the pressure plates of both pumps. The two bullet saw plates and springs can be temporarily assembled in advance, reducing assembly man-hours and reducing costs.

[Brief explanation of drawings]

Figure 1 is a front view of one embodiment of the present invention, and Figure 2 is A of Figure 1.
OA side sectional view, FIG. 3 is a BB sectional view of FIG. 1, and FIG. 4 is a system diagram of the present invention. ■... Housing, 2... Electromagnetic clutch, 3.10.
...D-tar, 4. ], 1...Cam ring, 5...End play 1, 6.12...Side plate, 8゜9...Drive shaft, 18...Check valve, 15...Flip, 16...・I & quantity control valve, 17.. Suction pipe, 18-.. High pressure chamber, 19.20.21.22+2.
221L...Aisle, 20'...Return passage, 25.
・Pulley, 26... Spring, 27... Drive plate, 28
...Target, drive plate, 80...Excitation coil, 84.85
... Vane, 39 ... Supply port, 40 ... Bulkhead, 4
1... Pump chamber, 42... Bearing mounting part, 48... Bearing, 45.47.48... Bearing bushing, 50.51
, 52. 58... Passage, 55... Relief valve, 56
...Reservoir tank, 57...Power control pulp, 58...Fluid cylinder, 59...Engine speed sensor, 60...Circuit pressure sensor, 61
...Control device, 62...Batch IJ-167...
Valve chamber, 68...Plug, 69...Variable throttle, Pl.
...Small capacity pump, P2...Large capacity pump'I P
S...Power steering device. Patent issued 1 Koyo Automatic Machine Co., Ltd. Koyo Seiko Co., Ltd. Figure 1 Figure 3 Figure 2

Claims (4)

[Claims] (1) In a pump device that includes two pumps in a housing and selectively supplies pressure fluid discharged from one or both of the two pumps to a power steering device, the pressure fluid discharged from the two pumps is A pump device for a ζ power steering device, characterized in that the pressure fluid is introduced into a high pressure chamber formed between the two pumps, and the introduced pressure fluid is supplied to the power steering device. (2) The two pumps are held against both end walls of the housing by the two pressure pumps facing each other and the springs installed between the plates, and the pumps are discharged from the two pumps. The pressure fluid is introduced into the spring housing space between the two plates through fluid introduction ports formed in each of the pressure plates, and the introduced fluid is supplied from the space to the power steering device. A pump device for a power steering device according to claim 1. (3) A pump device for a power steering device according to claim 1, wherein a check valve for preventing backflow of fluid is installed in each of the fluid inlets formed in the two pressure plates. (4) The two pump means are a first pump that is constantly driven and a second pump that is selectively driven, and the backflow of fluid is prevented only through the fluid inlet formed in the pressure plate that clamps the second pump. 2. A pump device for a power steering device according to claim 1, further comprising a check valve for preventing such damage.