JP2009030510A - Gear pump and brake device provided with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear pump capable of providing high volumetric efficiency even with low viscosity fluid such as high temperature brake fluid and of reducing friction resistance. <P>SOLUTION: This device is provided with two gears 31, 32 of which rotary shafts 51, 52 are arranged substantially in parallel and which rotate while being meshed mutually, a pair of side plates 34A, 34B which are externally inserted on the rotary shafts 51, 52 and which rotatably grip the two gears from both sides in an axial direction of the rotary shaft, and a seal block 33 which seals parts between parts of tooth tip of the gears 51, 52 and the side plates 34A, 34B. A part where the gears 31, 32 and the seal block 33 contact and diameter Dc of an outer circumferences 49 of contact surfaces of the gears 31, 32 and the side plates 34A, 34B which are in a range outside of a gear meshing parts are set not greater than a tooth bottom diameter Dd of the gears. Diameter Da of an inner circumference of a contact surface of the side plates 34A, 34B and the gears 31, 32 is set same as or slightly larger than outer diameter Dd of the rotary shafts 51, 52. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gear pump, and more particularly to a gear pump suitable for pressurizing and discharging a low-viscosity fluid such as gasoline and high-temperature brake oil as well as a fluid pressure source such as a hydraulic device and a brake device including the gear pump. About.

  In the rotary gear pump, as a prior art that can reduce the side clearance as much as possible without incurring excessive torque loss or seizure, and particularly improve the discharge efficiency at the time of high pressure discharge, it is described in Patent Document 1. Things are known. The apparatus described in Patent Document 1 is an internal gear pump, and is provided with a resin coating layer on each side plate portion side sliding surface which is a surface on the side plate portion side facing the outer rotor and the inner rotor.

  As a conventional technology that can reduce the friction energy when shearing the oil film in the gap between the gear and the side plate and the friction energy when the gear and the side plate are in contact with each other, and can reduce the loss of rotational torque of the gear The thing of patent document 2 is known.

  The device described in Patent Document 2 is an external gear pump, and is provided with an oil reservoir that retains and retains hydraulic oil in the gear chamber, thereby reducing the frictional energy between the gear and the side plate and reducing the loss of rotational torque of the gear. Thus, the time required for increasing the pressure to the predetermined pressure can be shortened.

Japanese Patent Laid-Open No. 10-299669 Japanese Patent Laid-Open No. 11-218084

  However, the above prior art has the following problems. That is, in the apparatus described in Patent Document 1, resin coating layers are provided on the side plate portion side sliding surfaces, respectively, but it is difficult to ensure long-term durability due to wear of the resin coating layers. It is done.

  When the brake device on which this inscribed gear pump is mounted is designed to drive the pump only when the brake hydraulic pressure is electronically controlled as in ABS (anti-lock brake device) control, Can only be used for a short time throughout the life of the vehicle, so long-term durability is not required.

  However, in recent years, electronic control of automobiles has progressed, and even in brakes, there is no mechanical connection between the brake pedal and the wheel cylinder (the part that receives the hydraulic pressure by the piston to operate the brake), and the braking force is generated by an electrical signal. The spread of BBW (brake-by-wire) systems for control is expected. In this system, it is necessary to generate the brake fluid pressure during normal braking without relying on the driver's pedaling force, so it is necessary to drive the pump even during normal braking. For this reason, both the pump operation time and the number of on / off operations are large, and high durability is required for the pump. However, the device described in Patent Document 1 has a problem that it is difficult to apply the system to the system because it is difficult to ensure durability for a long time.

  Further, the device described in Patent Document 2 is an external gear pump, and an oil reservoir for retaining and retaining hydraulic oil in the gear chamber is provided to reduce the frictional energy between the gear and the side plate. It is considered that the frictional energy increases due to the contact between the oil reservoir edge and the gear. The contact between the oil reservoir edge and the gear is only in the initial stage of operation, and it is expected that the edge portion will be worn out immediately, but in this case, the wear powder is mixed in the system, which is not preferable. Further, it is conceivable to remove the oil reservoir edge at the time of processing, but this is not preferable because the number of processing steps increases and the cost increases.

  The present invention has been made in consideration of the above problems, and the object of the present invention is to obtain a high volumetric efficiency even with a low-viscosity fluid such as a high-temperature brake fluid and to provide a frictional resistance. An object of the present invention is to provide a gear pump that can be reduced as much as possible.

  Another object of the present invention is to provide a brake device using a gear pump excellent in durability and the like suitable for a BBW system that controls a braking force by an electric signal every time a normal brake is applied.

  In order to achieve the above object, one of the gear pumps according to the present invention basically has two rotating gears that are arranged substantially parallel to each other and rotated in mesh with each other, and is extrapolated to the rotating shaft. And a pair of side plates that sandwich the two gears so as to be rotatable from both sides in the axial direction of the rotary shaft, and a seal block that seals fluid between a part of the gear teeth and the side plates.

  Further, the diameter of the outer periphery of the contact surface of the side plate with the gear other than the portion where the gear and the seal block are in contact with each other and the meshing portion of the gear is equal to or smaller than the diameter of the root circle of the gear. It is said.

  In a preferred embodiment, the diameter of the inner periphery of the contact surface of the side plate with the gear is the same as or slightly larger than the outer diameter of the rotating shaft.

  In another preferred embodiment, a case that houses the rotating shaft, gears, side plate, and seal block, and a seal member that is inserted between the case and the side plate to divide the inside of the case into a low pressure portion and a high pressure portion. The side plate and the gear are supported by the case via the seal member, and the seal member is attached to an installation portion provided in the case.

  The other one of the gear pumps according to the present invention basically includes two gears whose rotational shafts are disposed substantially in parallel and mesh with each other, and the two gears that are extrapolated to the rotational shafts. And a seal block that seals fluid between a part of the tooth tips of the gear and the side plate.

  And, on the inner peripheral portion of the side plate on the contact surface side with the gear, a concave contact portion made of a curved surface such as a conical surface or a spherical surface is provided, and on the inner peripheral portion of the gear on the contact surface side with the side plate, A convex contact portion having a curved surface such as a conical surface or a spherical surface that is in partial contact with the concave contact portion is provided, and a seal portion is configured by partial contact between the concave contact portion of the side plate and the convex contact portion of the gear. It is characterized by being.

  In this case, preferably, the convex contact portion of the gear is manufactured separately from the main body portion of the gear.

  On the other hand, the brake device according to the present invention includes the above-described gear pump. Specifically, the gear pump, the electric motor that rotationally drives the gear pump, and the pedaling force according to the pedaling force on the pedal A pedal force signal generating device that generates a signal; and an electric motor control unit that generates a brake fluid pressure signal based on the pedal force signal and supplies the brake hydraulic pressure signal to the electric motor, wherein the gear pump is supplied from the electric motor control unit. A brake fluid pressure corresponding to a brake fluid pressure signal supplied to the electric motor is generated.

  In the gear pump according to the present invention, the diameter of the outer periphery of the contact surface between the gear and the side plate where frictional resistance is generated is equal to or less than the root diameter of the gear, and more preferably, the inner diameter of the contact surface is the rotational shaft. Since the diameter is equal to or greater than the outer diameter, high volumetric efficiency can be obtained even with a low-viscosity fluid such as high-temperature brake fluid, and frictional resistance can be effectively reduced.

  In addition, it is possible to provide a highly durable gear pump suitable for a BBW system that controls a braking force by an electric signal every time a normal brake is applied.

  Further, a concave contact portion made of a curved surface such as a conical surface or a spherical surface is provided on the inner peripheral portion of the side plate, and a convex surface having a curved surface such as a conical surface or a spherical surface partially contacting the concave contact portion is provided on the inner peripheral portion of the gear. Since the contact portion is provided, and the concave contact portion of the side plate and the convex contact portion of the gear are in partial contact to form a seal portion, a high-precision part is not required and the contact surface becomes easy to adapt. Further, since the sealing performance is improved and the sealing surface is closer to the rotating shaft side, the radius of the contact surface can be reduced, and the frictional resistance of the gear pump can also be reduced.

Hereinafter, embodiments of the gear pump of the present invention will be described with reference to the drawings.
FIG. 1 is a transverse sectional view showing an embodiment of a gear pump of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. FIG. 3 is a perspective view of internal components of the gear pump according to the present embodiment.

  In FIG. 1, a drive gear 31 that is externally fitted and fixed to a rotary shaft (drive shaft) 51 via a bearing 39 is pivotally supported by a casing 37 and a cover 41. An electric motor (not shown) is connected to the drive shaft 51, and the drive shaft 51 and the drive gear 31 rotate as the motor rotates. The driven gear 32 that is externally fitted and fixed to the rotary shaft (driven shaft) 52 has a tooth width substantially equal to that of the drive gear 31 and is disposed so as to mesh with each other, and the drive gear 31 and the driven gear 32 rotate. Perform pump operation.

  The seal side plates 34A and 34B are extrapolated to the drive shaft 51 and the driven shaft 52, slidably contact the side surfaces of both gears 31 and 32, and a side seal that is a seal between the gears 31 and 32 and the seal side plates 34A and 34B. In addition, it also functions as a bearing for the drive shaft 51 and the driven shaft 52 that serve as the rotation shaft. Both shafts of the drive gear 31 and the driven gear 32 are supported in parallel and at a predetermined interval by the seal side plates 34A and 34B. As shown in FIGS. 2 and 3, the seal side plates 34A and 34B have a suction port 35 (IN) serving as a suction hole, and the outer edge R in the vicinity of the suction port 35 of the seal side plates 34A and 34B is: It is formed substantially equal to the diameter of the tip circle of both gears 31 and 32.

  As shown in FIG. 2, the casing 37 has a cylindrical shape inside and has a predetermined gap so that the drive gear 31 and the driven gear 32 do not come into contact with each other. The cylindrical portion depth of the casing 37 is slightly deeper than the thickness of the seal side plates 34A and 34B and the drive gear 31 or the driven gear 32 overlapped, so that the seal side plate 34A and the cover 41, the seal side plate 34B and the casing 37 The seal side plates 34A and 34B and the gears 31 and 32, which are internal components of the gear pump, are not in direct contact with each other, and the elastic force of the seal members 38A and 38B that are elastic bodies inserted between the cover 41 and the casing 37, respectively. Is supported through.

  As shown in FIGS. 3 and 4, the seal members 38 </ b> A and 38 </ b> B are fitted to convex portions 44 provided on the seal side plates 34 </ b> A and 34 </ b> B. The convex portions 44 of the seal side plates 34A and 34B are made slightly smaller than the inner peripheral shape of the seal members 38A and 38B.

  The seal block 33 is a component that minimizes the gap between the gears 31 and 32 and the gear tips 31 and 32 in the vicinity of the suction port 35. The seal block 33 has seal surfaces 46A and 46B (see FIG. 2) opposed to the tooth tips of the gears 31 and 32. The seal surfaces 46A and 46B each have an inner diameter of the tooth tip circle of the gears 31 and 32. Are formed almost equally. The seal block 33 is supported in a state where the seal surfaces 46A and 46B are joined to the outer edges R of the seal side plates 34A and 34B, thereby reducing the gap between the gears 31 and 32 and the tooth tip seal. It is carried out. As described above, the seal block 33 includes the seal surfaces 46A and 46B that seal between the gear tips 31 and 32 and the side plates 34A and 34B.

  The seal block 33 has a predetermined gap with respect to the cover 41 and the casing 37 so as not to contact the cover 41 and the casing 37. The seal block 33 is held by the cover 41 and the casing 37 via seal members 38A and 38B installed on the seal side plates 34A and 34B, and the movement of the seal block 33 in the direction of the drive shaft 51 is restricted. In this way, the seal block 33, the cover 41, and the casing 37 are sealed by the seal members 38A and 38B.

  The suction port 35 is formed in the seal side plates 34 </ b> A and 34 </ b> B, the seal block 33, and the casing 37. The fluid sucked from the suction port 35 by the pump action of the gears 31 and 32 passes between the gears 31 and 32 and the seal block 33 and is discharged into the casing 37 at a high pressure. When the fluid is filled in the casing 37, the fluid is discharged to the outside of the gear pump 3 from a discharge port 36 (OUT) formed in the casing 37.

The gear pump 3 of the present embodiment is a so-called movable side plate type seal block type gear pump. The side surfaces of the gears 31 and 32 are sealed with seal side plates 34A and 34B, and the tooth tips of the gears 31 and 32 are sealed with a seal block 33 to minimize internal leakage of the pump.
The role of the seal side plates 34A and 34B is to keep the gap between the side surfaces of the gears 31 and 32 constant regardless of the discharge pressure, and is basically in contact with the gears 31 and 32. There is no macroscopic gap.

  The sealing members 38 </ b> A and 38 </ b> B seal between the suction port 35, which is a low pressure part, and the high pressure part in the casing 37. That is, the inner side (inner peripheral side) of the seal members 38A and 38B is a low pressure part, and the outer side (outer peripheral side) of the seal members 38A and 38B is a high pressure part. Further, the seal members 38A and 38B determine the pressure distribution on the back surface (the surface on the cover 41 or the casing 37 side) of the seal side plates 34A and 34B, and balance the pressure in the direction of the drive shaft 51. If the inner surfaces (the surfaces on the gears 31 and 32 side) of the seal side plates 34A and 34B become high pressure, the fluid led to the gap between the back surfaces of the seal side plates 34A and 34B (the surface on the cover 41 or casing 37 side) also becomes high pressure. Therefore, as a result of maintaining the pressure balance in the direction of the drive shaft 51, the seal side plates 34A, 34B always keep contact with the side surfaces of the gears 31, 32. Further, an appropriate pressing force is applied to the gears 31 and 32 via the seal side plates 34A and 34B by the elastic force of the seal members 38A and 38B, and a side seal as a seal between the gears 31 and 32 and the seal side plates 34A and 34B is provided. Do well.

  The seal block type gear pump 3 limits the low pressure region in the vicinity of the suction port 35 to the inner surface of the seal block 33 by limiting the tooth tip seal by the seal block 33 to one or two tooth tips of the gears 31 and 32. The pressure is limited to a very narrow range, and all the remaining portions are set as a high pressure region to achieve pressure balance on the outer circumferences of the gears 31 and 32. As a result, the load that the drive shaft 51 acts on the bearing portions of the bearing 39 and the seal side plates 34A and 34B and the load that the driven shaft 52 acts on the bearing portions of the seal side plates 34A and 34B can be reduced.

  As described above, the seal side plates 34 </ b> A and 34 </ b> B are in contact with the gears 31 and 32 in order to prevent internal leakage of the gear pump 3. The seal side plates 34A and 34B are always kept in contact with the fluid introduced into the gap between the inner surfaces of the seal side plates 34A and 34B (the surfaces on the gears 31 and 32 side) and the back surfaces of the seal side plates 34A and 34B (the surface on the cover 41 or casing 37 side) A fluid force acts in the direction of the drive shaft 51 so as to maintain contact with the side surfaces of the gears 31 and 32. Further, an appropriate pressing force is applied to the gears 31 and 32 via the seal side plates 34A and 34B by the elastic force of the seal members 38A and 38B. Thus, since the pressing force is applied to the gears 31 and 32 from the seal side plates 34A and 34B, a frictional resistance (friction torque) is generated between the seal side plates 34A and 34B and the gears 31 and 32. When this frictional resistance is large, the mechanical efficiency of the gear pump 3 is lowered. Further, when the frictional resistance is large, it is not preferable because it leads to an increase in size and cost of the motor for driving the gear pump 3, and thus it is necessary to keep the frictional resistance small.

  The frictional resistance (friction torque) is determined by the product of the load acting on the contact surface, the coefficient of friction between the contact surfaces, and the radius of the contact surface. The frictional resistance can be reduced by reducing the radius of the contact surface. On the other hand, a seal width is necessary in order to prevent fluid leakage from the outer diameter of the high-speed gears 31 and 32 to the inner diameter direction of the low-speed gears 31 and 32.

  Therefore, in this embodiment, as shown in FIGS. 5 and 6, the gears 31, 32 and the gears 31, 32 and the seal side plates 34 </ b> A, 34 </ b> B are secured in order to reduce the frictional resistance. The diameter Da of the inner periphery 48 of the contact surface 47 between the seal side plates 34A and 34B is the same as or slightly larger than the outer diameter Db of the drive shaft 51 and the driven shaft 52, and the diameter Dc of the outer periphery 49 of the contact surface 47 is a gear. The diameter Dd is 31 or less of the root circle 50 of 31 and 32. The diameter Dc of the outer periphery 49 of the contact surface 47 is appropriately set so as to suppress fluid leakage from the outer periphery of the gears 31 and 32 to the inner peripheral direction of the gears 31 and 32 due to the pressure used by the gear pump 3. . In addition, the diameter Dc of the outer periphery 49 of the contact surface 47 is preferably as small as possible in order to reduce the frictional resistance.

  Note that reducing the seal width, which is the difference between the diameter Da of the inner periphery 48 of the contact surface 47 and the diameter Dc of the outer periphery 49 of the contact surface 47, does not necessarily lead to a decrease in sealing performance. Since the contact surfaces 47 are in contact with each other, a slight gap is left due to the processing accuracy of the surfaces. When the contact surface 47 is small, a gap is less likely to occur because the contact area is smaller than when the contact surface 47 is large. In order to eliminate the gap between the contact surface 47 and the gears 31 and 32, it is not preferable to process the plane of the component with high accuracy because it costs processing costs. When the area of the contact surface 47 is small, not only is the gap difficult to form because the contact area is small, but also the flatness management of the parts at the time of processing becomes easy, and the cost can be reduced.

  Moreover, the reason why the diameter Dc of the outer periphery 49 of the contact surface 47 is set to be equal to or smaller than the root diameter Dd of the gears 31 and 32 is as follows. When the diameter Dc of the outer periphery 49 of the contact surface 47 is made larger than the diameter Dd of the root circle 50, the tooth edge portions of the gears 31 and 32 come into contact with the contact surface 47. This is because if the burrs remain on the edge portions of the gears 31 and 32, the frictional resistance between the contact surface 47 and the gears 31 and 32 increases. In addition, the edge portions of the gears 31 and 32 start to scrape the fluid on the contact surface 47 toward the casing 37, and the oil film between the contact surface 47 and the gears 31 and 32 is cut, which causes an increase in frictional resistance. is there.

  Note that the contact surface 47 in the vicinity of the suction port 35 of the seal side plates 34A and 34B (both are denoted by reference numeral 34), that is, the portion where the gears 31, 32 and the seal block 33 are in contact and the meshing portion of the gears 31, 32 are as follows. The entire side surfaces of the gears 31 and 32 are in contact with each other. This is because the fluid sucked from the suction port 35 enters a small chamber formed by the tooth spaces of the gears 31 and 32, the seal block 33, and the seal side plate 34, and efficiently moves toward the discharge port 36 as the gears 31 and 32 rotate. This is because it is carried out. The portion of the seal side plate 34 that contacts the entire side surfaces of the gears 31 and 32 is made to coincide with the contact width of the seal block 33 so as to correspond to one or two teeth of the gears 31 and 32.

  As described above, in the present embodiment, the diameter Dc of the outer periphery of the contact surface 47 between the gears 31 and 32 and the seal side plate 34 is set to be equal to or smaller than the root diameter Dd of the gears 31 and 32. The frictional resistance can be reduced while ensuring the sealing performance between the side plates 34.

  In the above embodiment, the seal member 38 is installed on the convex portion 44 of the seal side plate 34, but it may be installed on the casing 37 and the cover 41. Hereinafter, an embodiment in which the seal member 38 is installed on the casing 37 and the cover 41 will be described.

  As shown in FIG. 7, the casing 37 is provided with a convex portion 53. The convex portion 53 is made slightly smaller than the inner peripheral shape of the seal members 38A and 38B. In addition, although the convex part is similarly provided in the cover 41 side, description is abbreviate | omitted. As shown in FIG. 8, the seal members 38 </ b> A and 38 </ b> B are fitted to the cover 41 and the convex portion 53 of the casing 37. Since the seal member 38 is installed on the cover 41 and the casing 37, the convex portion of the seal side plate 34 which is the first embodiment can be removed as shown in FIG.

  In the present embodiment, the diameter Dc of the outer periphery 49 of the contact surface 47 of the seal side plate 34 is made smaller than the diameter Dd of the root circle 50 of the gears 31 and 32 in order to reduce the frictional resistance. As a result, the high pressure partial area on the inner surface of the seal side plate 34 increases, so that the pressure balance in the direction of the drive shaft 51 is maintained and the high pressure partial area on the back surface of the seal side plate 34 is adjusted so that the seal side plate 34 and the gears 31 and 32 are in contact. Need to increase. That is, the convex portion 44 of the seal side plate 34 needs to be shaved in the direction of the drive shaft 51 and the driven shaft 52. In order to hold the seal member 38, the convex portion 44 of the seal side plate 34 needs to have a predetermined thickness, and when this thickness cannot be secured on the seal side plate 34 side, It is effective to install the seal member 38. In FIG. 8, the configuration and operation other than the attachment portion of the seal member 38 are the same as those in the above-described embodiment, and thus the description thereof is omitted.

  In the above embodiment, the seal member 38 is installed on the cover 41 and the convex portion 53 of the casing 37, but the convex portion for installing the seal member 38 may be a separate member. Hereinafter, an embodiment in which the member on which the seal member 38 is installed is a separate member will be described.

  FIG. 10 shows the seal member bracket 54 of the present embodiment. The seal member bracket 54 is provided with a positioning convex portion 55 and a suction port 35. The positioning convex portion 55 is fitted into a positioning concave portion 56 installed in the casing 37 shown in FIG. 11 and regulates the position of the seal member bracket 54. A positioning recess 56 is similarly provided on the cover 41 side and a seal member bracket 54 is installed, but the description thereof is omitted. The seal member bracket 54 is made slightly smaller than the inner peripheral shape of the seal members 38A and 38B, and the suction port 35 of the seal member bracket 54 has a slightly larger hole than the suction port 35 of the casing 37. Even if 54 is slightly deviated, fluid suction is not hindered. The seal member bracket 54 may be a metal or a resin. Depending on the set pressure of the gear pump 3, the material can be selected in consideration of the material strength.

  As described above, in the present embodiment, as shown in FIG. 7, since the convex portion 53 is not provided on the casing 37, the processing of the casing 37 is facilitated, and an increase in cost can be suppressed. Further, if the seal member bracket 54 is manufactured by resin molding, the cost increase can be further suppressed. The configuration and operation other than the attachment portion of the seal member 38 are the same as those in the first embodiment described above, and a description thereof will be omitted.

  Next, other embodiments of the gear pump according to the present invention, in particular, the gears 31 and 32 and the seal side plate 34 will be described.

  FIG. 12 is a cross-sectional view of the vicinity of the contact surface between the seal side plates 34A and 34B (both are denoted by reference numeral 34) and the gears 31 and 32 of the present embodiment. In FIG. 12, only the vicinity of the driven shaft 52 is shown, but the vicinity of the drive shaft 51 is the same. As shown in FIG. 12, a concave contact portion 58 formed of a conical surface is provided on the inner peripheral portion of the seal side plate 34 on the contact surface side with the gear 32, and the inner peripheral portion on the contact surface side of the gear 32 with the side plate 34. Further, a convex contact portion 57 having a conical surface that is in partial contact with the concave contact portion 58 is provided, and the concave contact portion 58 of the side plate 34 and the convex contact portion 57 of the gear 32 are in partial contact with each other to provide a seal. A portion (seal surface 59) is formed. As shown in FIG. 13, the concave contact portion 58 of the seal side plate 34 is a spherical surface, and the surface of the convex contact portion 57 of the gear 32 is a conical surface. May be other curved shapes.

  By doing in this way, a highly accurate part is not required and a contact surface becomes easy to adapt, Therefore Sealing property improves.

  As described above, by providing the seal side plate 34 and the gears 31 and 32 with the concave contact portion 58 and the convex contact portion 57 respectively, the seal surface 59 approaches the driven shaft 52 side as shown in FIG. The radius r of the surface can be reduced. Therefore, the frictional resistance of the gear pump 3 can be reduced.

  Moreover, although the convex contact part 57 is produced integrally with the gears 31 and 32 main body part in the above, as shown in FIG. 14, the gear 31, 32 main body part and the convex contact part 60 are produced separately. May be. As a result, the gears 31 and 32 can be easily processed, so that an increase in cost can be suppressed.

  Then, the example which used the gear pump 3 demonstrated above for the hydraulic brake device for vehicles is demonstrated.

  FIG. 15 is a system configuration diagram illustrating an example of a vehicle brake device in which the gear pump 3 according to the embodiment of the present invention is used. When the driver steps on the brake pedal 6, the pedaling force is converted into an electric signal by the signal generator 7, and the electric motor 2 and the gear pump of the embodiment are connected to the electric motor 2 via the controller 8 which is an electric motor control means. 3 is driven. The controller 8 includes a calculation block 81, a control block 82 and a monitor block 83. In the controller 8, necessary brake fluid pressure and motor rotation speed are calculated by the calculation block 81 from the input from the signal generation device 7, wheel speed, battery voltage, etc., and an output signal (brake fluid pressure signal) from the control block 82. To control the electric motor 2. At this time, the control accuracy is improved by feeding back information on the brake fluid pressure and the motor rotation number via the monitor block 83 as necessary. The gear pump 3 sucks the brake fluid from the reservoir tank 1, pressurizes and supplies the brake fluid to the wheel cylinder 4, and gives the brake fluid pressure, whereby the brake acts on the vehicle. The brake fluid pressure can be reduced by removing the brake fluid to the reservoir tank 1 side by the pressure reducing device 5 indicated by a dotted line, but it is also possible to perform the pressure reducing operation only by the gear pump 3 without using the pressure reducing device 5. .

  The pressure reduction by the gear pump 3 can be performed very quickly by rotating the pump in the reverse direction, and can also be performed only by stopping the pump or reducing the rotational speed. This is because there is a so-called internal leak in which the brake fluid leaks from the discharge port side to the suction port side due to a minute gap in the gear pump 3. By applying pressure and depressurization only with the gear pump 3, a brake device having a simple structure and being inexpensive can be provided.

  In the brake device described above, since the gear pump 3 is driven every time the driver steps on the brake pedal, the operation time is longer than that of the pump used in the ABS unit, and the number of on / off times is larger. Desired. In addition, since the pump is normally used for braking, it is important that the pump has little pulsation and can smoothly control the brake fluid pressure.

  For this reason, in the brake device of this example, the circumscribed gear pump of the above-described embodiment is adopted as the pump. A plunger pump used as a pump for a normal ABS unit is inexpensive and relatively easy to ensure durability, but has a disadvantage in that pressure pulsation is large because suction and discharge are intermittent. On the other hand, the gear pump has the advantages of low pulsation and low cost, and is usually suitable for a pump for braking.

The cross-sectional view which shows one Embodiment of the gear pump of this invention. The longitudinal cross-sectional view which shows one Embodiment of the gear pump of this invention. The perspective view which shows the internal component of the gear pump shown by FIG. The figure which looked at the seal side board of the gear pump shown in FIG. 1 from the back side. The figure explaining the contact surface with the gearwheel of the seal side plate of the gear pump shown in FIG. The figure which looked at the seal side plate of the gear pump shown in FIG. 1 from the inner surface side. The figure which shows other embodiment of the casing of the gear pump of this invention. The cross-sectional view which shows other embodiment of the gear pump of this invention. The figure which shows other embodiment of the seal side plate of the gear pump of this invention. The figure which shows embodiment of the sealing member bracket of the gear pump of this invention. The figure which shows other embodiment of the casing of the gear pump of this invention. The figure which shows other embodiment of the seal side plate and gearwheel of the gear pump of this invention. The figure explaining the sealing surface of the gear pump of this invention. The figure which shows other embodiment of the seal side plate and gearwheel of the gear pump of this invention. The figure which shows an example of the brake device which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reservoir tank, 2 ... Motor, 3 ... External gear pump, 4 ... Wheel cylinder, 5 ... Decompression device, 6 ... Brake pedal, 7 ... Signal generation device, 8 ... Controller, 31 ... Drive gear, 32 ... Drive gear 33 ... Seal block, 34, 34A, 34B ... Seal side plate, 35 ... Suction port, 36 ... Discharge port, 37 ... Casing, 38, 38A, 38B ... Seal member, 39 ... Bearing, 41 ... Cover, 42 ... O-ring 43 ... Rotating shaft seal, 44 ... Convex part, 46A, 46B ... Sealing surface, 47 ... Contact surface, 48 ... Contact surface inner periphery, 49 ... Contact surface outer periphery, 50 ... Dental root circle, 51 ... Drive shaft, 52 ... Drive shaft, 53 ... convex part, 54 ... sealing member bracket, 55 ... positioning convex part, 56 ... positioning concave part, 57 ... convex contact part, 58 ... concave contact part, 59 ... sealing surface, 60 ... convex contact member 81 ... operation block, 82 ... control block 83 ... monitor block.

Claims (7)

A pair of side plates that are arranged substantially parallel to each other, rotate in mesh with each other, and a pair of side plates that are extrapolated to the rotation shaft and sandwich the two gears from both sides in the axial direction of the rotation shaft. And a gear block including a seal block that seals fluid between a part of the tooth tips of the gear and the side plate,
The diameter of the outer periphery of the contact surface of the side plate with the gear other than the portion where the gear and the seal block are in contact with each other and the meshing portion of the gear is equal to or less than the diameter of the root circle of the gear. Gear pump.   2. The gear pump according to claim 1, wherein an inner diameter of a contact surface of the side plate with the gear is the same as or slightly larger than an outer diameter of the rotating shaft.   A case housing the rotating shaft, gears, side plate, and seal block; and a seal member inserted between the case and the side plate to divide the inside of the case into a low pressure portion and a high pressure portion, the side plate and The gear pump according to claim 1 or 2, wherein the gear is supported by the case via the seal member, and the seal member is attached to an installation portion provided in the case.   A pair of side plates that are arranged substantially parallel to each other, rotate in mesh with each other, and a pair of side plates that are extrapolated to the rotation shaft and sandwich the two gears from both sides in the axial direction of the rotation shaft. And a seal block that seals fluid between a part of the tooth tips of the gear and the side plate, a conical surface on an inner peripheral portion of the side plate on the contact surface side with the gear, A convex contact portion having a curved contact surface, such as a spherical surface, is provided with a concave contact portion having a curved surface such as a spherical surface, and a conical surface partially contacting the concave contact portion, a spherical surface or the like on the inner peripheral portion of the gear on the contact surface side with the side plate Is provided, and the seal portion is configured by the partial contact between the concave contact portion of the side plate and the convex contact portion of the gear.   The gear pump according to claim 4, wherein the convex contact portion of the gear is formed separately from the main body portion of the gear.   The brake device provided with the gear pump as described in any one of Claim 1 to 5.   The gear pump according to any one of claims 1 to 5, an electric motor that rotationally drives the gear pump, a pedaling force signal generation device that generates a pedaling force signal corresponding to a pedaling force on a pedal, and the pedaling force signal An electric motor control unit that generates a brake hydraulic pressure signal based on the electric motor control unit and supplies the brake hydraulic pressure signal to the electric motor, wherein the gear pump responds to the brake hydraulic pressure signal supplied from the electric motor control unit to the electric motor. Brake device characterized by generating brake fluid pressure.

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