JPH0663884U - Vane pump - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to obtain a vane pump capable of preventing the oil film from becoming thin and seizure easily occurring even when the temperature of the hydraulic oil rises. [Structure] A temperature sensitive member having a large coefficient of thermal expansion is sandwiched between the cam ring 9 and the side plate 11.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a vane pump suitable for being applied to a hydraulic power source such as a power steering device of an automobile.

[0002]

[Prior art]

 In this type of vane pump, as disclosed in, for example, Japanese Patent Laid-Open No. 63-167089, a cam ring for accommodating a rotor in which a plurality of vanes are mounted so as to be retractable in the radial direction is provided with a plate member on the front side and the rear side. It has a structure that is sandwiched by and is rotated by a drive shaft connected to the rotor.

[0003]

[Problems to be solved by the device]

 The vane pump has a slight gap between it and a plate member that holds the cam ring from both sides in order to smooth the rotation of the rotor in the cam ring. The oil film formed in this gap lubricates the space between the rotor and the plate member.

However, when the temperature of the hydraulic oil rises during rotation, the gap decreases due to thermal expansion of each member, and the oil film becomes thin. If this state continues, the rotor and the plate material will come into metal contact with each other, and seizure is likely to occur.

Therefore, the present invention has been made in view of the above circumstances, and obtains a vane pump capable of preventing the oil film from becoming thin and seizure easily occurring even when the temperature of the hydraulic oil rises. The purpose is to

[0006]

[Means for Solving the Problems]

 In view of the above, the present invention provides a rotor in which a plurality of vanes are mounted so as to be retractable in a substantially radial direction and rotated by a drive shaft, a cam ring that rotatably accommodates the rotor, and a plate member that sandwiches the cam ring from both sides. In the vane pump provided with, a temperature sensitive member having a large coefficient of thermal expansion is sandwiched between the cam ring and the plate member.

[0007]

[Action]

 When the temperature of the hydraulic oil rises, the temperature sensitive member expands, increasing the gap between the rotor and the plate member. As a result, the suction section and the discharge section of the pump chamber communicate with each other through this gap, the work of the pump decreases, the temperature rise of the hydraulic oil is suppressed, and at the same time, the high pressure oil in the pump chamber enters the gap. As a result, an oil film sufficient for lubrication is formed. Therefore, metal contact of the sliding portion is prevented, and seizure is prevented.

[0008]

【Example】

 An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing the entire structure of a vane pump to which an embodiment of the present invention is applied. In the figure, 1 is a housing, 2 is a drive shaft, and 3 and 4 are bearings and bushes which respectively support the drive shaft 2. The housing 1 is formed with an annular recess 5 having one end open, and a pump unit 6 is housed in the annular recess 5. The pump unit 6 accommodates a rotor 8 having a plurality of vanes 7 mounted in a radial direction so that the vane 7 can be retracted and retracted in a cam ring 9, and the cam ring 9 serves as a cover plate (plate member) 10 that covers the open end of the annular recess 5. The structure sandwiched by the side plate (plate member) 11 is provided. The tip of the vane 7 attached to the rotor 8 is in sliding contact with the inner peripheral cam surface 9 a of the cam ring 9. A pump chamber 12 is formed by the cam ring 9, the rotor 8 and the two adjacent vanes 7. The volume of the pump chamber 12 changes due to the rotation of the rotor 8, and a suction section is formed in a portion where the volume increases due to this change, and a discharge section is formed in a portion where the volume decreases.

A temperature sensitive member 13 having a larger coefficient of thermal expansion than the cam ring 9 and the side plate 11 is provided between the cam ring 9 and the side plate 11. In this embodiment, the plurality of temperature sensitive members 13 are provided symmetrically with respect to the center of rotation of the rotor 8, but the present invention is not limited to this, and the temperature sensitive member 13 is formed into an annular plate shape. It may be sandwiched between the cam ring 9 and the side plate 11. Further, it may be arranged not only between the cam ring 9 and the side plate 11 but also between the cam ring 9 and the cover plate 10.

Reference numeral 14 is a high pressure chamber in which the discharge oil is discharged from the pump chamber 12. A suction port 15 communicates with a reserve tank (not shown), and guides the hydraulic oil to the pump chamber 12 via the low pressure passage 16. On the other hand, a flow rate control valve 18 is provided between the high pressure passage 17 and the low pressure passage 16 which communicate with the high pressure chamber 14, and the flow rate control valve 18 causes an excess amount of the discharged oil introduced into the high pressure chamber 14. Is recirculated to the low pressure passage 16, and the discharge amount discharged from the discharge port (not shown) communicating with the flow rate control valve 18 to the actuator is controlled to a constant amount.

According to such a configuration, the rotor 8 is rotationally driven via the drive shaft 2, so that the pump chamber 12 formed between the adjacent vanes 7 expands and contracts, and the hydraulic oil flows from the suction port 15 to the pump chamber 12. It is introduced into the pump chamber 12 through the low pressure passage 16 and is further discharged into the high pressure chamber 14. After that, the hydraulic oil in the high-pressure chamber 14 is guided from the high-pressure passage 17 to the flow rate control valve 18, and through the flow rate control valve 18 from a discharge port (not shown) to an actuator such as a power steering device.

When the vane pump is operated at high speed, the amount of oil discharged from the pump chamber 12 to the high pressure chamber 14 increases. Even if this amount of oil increases, the amount of oil discharged from the discharge port is controlled by the flow rate control valve 18, so a constant flow rate is discharged, but the working oil is pumped into the suction section of the pump chamber 12. Is transferred to the discharge section from where it is supplied with a high pressure and discharged into the high pressure chamber 14, so that the energy increases by that amount and the oil temperature rises. When the temperature of the oil rises, the oil film between the rotor 8 and the plate members 10 and 11, which are the sliding surfaces, becomes thin and seizure easily occurs. At this time, however, the seizure between the cam ring 9 and the side plate 11 is likely to occur. The expansion member 13 provided expands, and the gap between the rotor 8 and the side plate 11 increases.

As a result, the suction section and the discharge section of the pump chamber 12 are communicated with each other through the gap, the work amount of the pump, that is, the work amount for increasing the pressure of the hydraulic oil is reduced, and an increase in the temperature of the hydraulic oil is suppressed. At the same time, the high-pressure oil in the pump chamber enters the gap to form an oil film sufficient for lubrication. Therefore, metal contact of the sliding portion is prevented, and seizure is prevented.

[0015]

[Effect of device]

 As described in detail above, according to the present invention, a plurality of vanes are attached to be retractable in a substantially radial direction, a rotor that is rotated by a drive shaft, a cam ring that accommodates the rotor in a rotating manner, and a rotor that rotates. In a vane pump having a plate member that holds the cam ring from both sides, a temperature sensitive member having a large coefficient of thermal expansion is sandwiched between the cam ring and the plate member, so that the temperature of the hydraulic oil rises. Is suppressed, and high-pressure oil in the pump chamber enters into this gap to form an oil film sufficient for lubrication. Therefore, it is possible to easily obtain a vane pump with excellent durability by preventing metal contact of the sliding part and preventing seizure, and it is possible to obtain a great effect for practical use. To be

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along the line AA of FIG.

[Simple explanation of symbols]

 2 drive shaft 7 vane 8 rotor 9 cam ring 10 cover plate (plate member) 11 side plate (plate member) 13 temperature sensitive member

Claims (1)

[Scope of utility model registration request] 1. A rotor in which a plurality of vanes are mounted so as to be retractable in a substantially radial direction and which is rotated by a drive shaft, a cam ring which rotatably accommodates the rotor, and a plate member which sandwiches the cam ring from both sides. A vane pump comprising: a vane pump, wherein a temperature sensitive member having a large coefficient of thermal expansion is sandwiched between the cam ring and the plate member.