JP2008284941A - Cylinder mechanism and stroke simulator having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder mechanism in which the quantity of disc springs in use is effectively reduced and which can provide stable spring characteristics and a stroke simulator having the cylinder mechanism. <P>SOLUTION: This cylinder mechanism 11 comprises a housing 70, a piston 72 slidably held in the housing 70 and forming a fluid chamber 73 to which a hydraulic fluid is guided, and the disc springs 90, 92 for biasing the piston 72 to the fluid chamber 73 side. Inner slits 94 as cuts radially extending from the inner peripheral side to the outer peripheral side and outer slits 96 as cuts radially extending from the outer peripheral side to the inner peripheral side are formed in each of the disc springs 90, 92. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cylinder mechanism that urges a piston for forming a liquid chamber through which hydraulic fluid is guided by a disc spring, and a stroke simulator including the cylinder mechanism.

  2. Description of the Related Art In recent years, a motor cylinder or a hydraulic pump for applying hydraulic pressure to a braking force generator provided on a wheel based on operation information such as a pedaling force of a brake pedal (hereinafter also simply referred to as a pedal) input to an ECU of a vehicle Brake devices have been proposed that electrically control the drive. In this type of electronic control of brakes using electrical signals, the so-called brake-by-wire system, braking that is more faithful to pedal operation than the hydraulic control system in which a pedal and a master cylinder are directly connected has been widely used. And smooth braking can be realized.

  Usually, a brake device employing a brake-by-wire is provided with a stroke simulator (pedal simulator) for obtaining a reaction force against the depression of the pedal, and thereby, between the pedal depression amount (stroke, operation amount) and the depression force, Predetermined characteristics (stroke-pedal force characteristics) are given.

  Patent Document 1 discloses a stroke simulator including a cylinder mechanism that includes a piston that forms (defines) a fluid chamber through which hydraulic fluid is guided and a plurality of disc springs that bias the piston toward the fluid chamber. Yes.

Japanese Patent Laid-Open No. 6-211124

  In this type of stroke simulator, the second-curve spring characteristic of the disc spring is used to make the stroke-treading force characteristic non-linear, that is, the pedal operating torque (stepping rigidity) is small at the beginning of the pedal depression, and the pedal is As the pedal is depressed, the operating torque (step rigidity) can be increased, and the driver can feel a pedal operation without feeling uncomfortable. In this case, since the disc spring has a small displacement amount of one structural member, for example, in the conventional technique described in Patent Document 1, the overall displacement amount is increased by stacking a large number of disc springs. As a result, desired spring characteristics are secured.

  However, as the number of stacked disc springs increases in this way, the variation in the characteristics of each disc spring increases, so individual differences among products increase and the overall spring characteristics stabilize. Since it becomes difficult, it becomes difficult to create a fine pedal feeling. Furthermore, when the number of disc springs used is increased or a large disc spring is used, there is a problem that the manufacturing cost increases.

  The present invention has been made to solve the above-described conventional problems, and includes a cylinder mechanism that can effectively reduce the number of disc springs used, and that can obtain stable spring characteristics, and the cylinder mechanism. An object is to provide a stroke simulator.

  A cylinder mechanism according to the present invention includes a housing, a piston that is slidably held in the housing and forms a liquid chamber through which hydraulic fluid is guided, and a disc spring that biases the piston toward the liquid chamber. It is a cylinder mechanism provided, The notch which follows the radial direction is formed in the said disc spring, It is characterized by the above-mentioned.

  A stroke simulator according to the present invention is a stroke simulator that is connected to a master cylinder and generates a reaction force on a brake pedal by a hydraulic pressure generated by the master cylinder. The stroke simulator includes a housing, And a piston that forms a liquid chamber through which hydraulic fluid is guided by being driven forward and backward by the hydraulic pressure generated by the master cylinder, and a notch along a radial direction. And a disc spring for urging the liquid chamber toward the liquid chamber.

  According to such a configuration, the disc spring has a non-linear characteristic and has a sufficient amount of displacement due to the cutting, so that a desired amount of displacement of the piston, a stroke simulator, and the like using a small number of disc springs are provided. It is possible to obtain optimum spring characteristics. Furthermore, since the number of disc springs used can be reduced, it is possible to effectively prevent the variation in the characteristics of each disc spring from increasing due to the increase in the number of layers, and to suppress individual differences between products and stabilize It is possible to obtain the spring characteristics. In addition, since the number of disc springs used can be effectively reduced, the cylinder mechanism and the stroke simulator can be reduced in size and weight, and the cost can be reduced.

  According to the present invention, by using a disc spring having a cut, it is possible to obtain a non-linear spring characteristic and a sufficient amount of displacement that are optimal for a stroke simulator or the like while effectively reducing the number of disc springs used. Furthermore, since the number of disc springs used can be reduced, it is possible to effectively prevent the variation in the characteristics of each disc spring from increasing due to an increase in the number of stacks, while ensuring a sufficient amount of displacement, It is possible to obtain a stable desired spring characteristic by suppressing individual differences. In addition, since the number of disc springs used is reduced, it is possible to reduce the size and weight of the cylinder mechanism and the stroke simulator, and to reduce the cost.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a cylinder mechanism according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to a brake device equipped with a stroke simulator as an application example of the cylinder mechanism.

  First, a brake device for a vehicle equipped with a stroke simulator (pedal simulator) to which a cylinder mechanism according to the present invention is applied will be described. FIG. 1 is a block circuit diagram of a brake device 10 equipped with stroke simulators 13L and 13R to which a cylinder mechanism 11 according to an embodiment of the present invention is applied.

  The brake device 10 is mounted on a vehicle such as an automobile, and based on the operation of a pedal (brake pedal) 12 by a driver (operator), a braking force generator (caliper, wheel cylinder, Brake cylinder) is a device that brakes the vehicle by holding the disks 15L and 15R with 14L and 14R to generate a braking force. In FIG. 1, only the left wheel LW and the right wheel RW constituting the front wheel side of the automobile are shown, and the rear wheel side is not shown, but the front wheel side (left wheel LW) is also shown on the rear wheel side. And the right wheel RW) and other configurations can be provided. Further, in the brake device 10, reference numerals for components provided on the left wheel LW side are denoted by “L”, reference numerals for components provided on the right wheel RW side are denoted by “R”, and the left wheel LW side and When collectively explaining the right wheel RW side, the above-mentioned “L” and “R” are omitted.

  The brake device 10 generates a braking force by a pedal 12 that is operated by a driver according to a driving condition, a master cylinder 16 that is driven in conjunction with the operation of the pedal 12, and the braking force generators 14L and 14R. Motor cylinders (hydraulic pressure generating units, caliper cylinders) 18L and 18R for applying a hydraulic pressure for the purpose. Each component of the brake device 10 is electrically connected to and controlled by the ECU 20 that is a control unit. That is, the brake device 10 includes a hydraulic pressure (hydraulic pressure) system that connects hydraulic pressure (hydraulic pressure) between the components and an electric system that electrically connects the components and the ECU 20. The In FIG. 1, a path (flow path) constituting the hydraulic system is indicated by a solid line, and a path (signal line) constituting the electrical system is indicated by a broken line. Examples of the liquid filled in the hydraulic system include brake fluid.

  As shown in FIG. 1, the pedal 12 includes a pedal operation information detection unit 22 that detects a force by which the driver depresses the pedal 12 (stepping force) and an amount (operation amount, stroke) of the pedal 12 operated by the driver. The detected value of the pedal operation information detection unit 22 is input to the ECU 20. For example, a torque sensor provided on the tread surface of the pedal 12 is used to detect the pedal force, and a potentiometer is used to detect the stroke. Note that the pedal operation information detection unit 22 may be configured to detect only the pedal effort.

  An electric actuator (reaction force motor) 24 is connected to the vicinity of the swing shaft on the base end side of the pedal 12. The electric actuator 24 adjusts the reaction force against the depression of the driver's pedal 12 under the control of the ECU 20, and can also be used for adjusting the position of the pedal 12. Since the electric actuator 24 can apply torque to the pedal 12, the electric actuator 24 may also serve as the function of the pedal operation information detection unit 22 that detects the depression force of the pedal 12.

  The master cylinder 16 includes two pistons 26L and 26R arranged in order in the axial direction, a rod 28 whose rear end is connected to the pedal 12 to drive the pistons 26L and 26R forward and backward, and the inside of the cylinder 16a is the piston 26L, It is composed of two pressurizing chambers 30L and 30R formed by being partitioned by 26R. The pressurizing chambers 30L and 30R are provided with return springs (elastic members) 32L and 32R that return the pistons 26L and 26R that have been moved by the depression of the pedal 12 to their original positions. The pressurizing chambers 30L and 30R are connected to the braking force generators 14L and 14R by main paths 33L and 33R.

  The motor cylinders 18L and 18R are configured such that the pistons 38L and 38R can be driven forward and backward in the cylinders 40L and 40R by connecting the rear ends of the rods 34L and 34R to brake motors (caliper motors) 36L and 36R. . The pressurizing chambers 42L, 42R constituting the motor cylinders 18L, 18R are connected to the main paths 33L, 33R via the paths 44L, 44R. That is, the pressurizing chamber 42 of the motor cylinder 18 is connected to the braking force generator 14.

  In the main paths 33L and 33R, a stroke simulator (SS) in which the cylinder mechanism 11 according to the present embodiment is applied to the master cylinder 16 side of the paths 44L and 44R via the paths 46L and 46R. 13L and 13R are connected.

  Further, passages 54 </ b> L and 54 </ b> R connected to the reserve tank 52 communicate with the pressurizing chambers 30 </ b> L and 30 </ b> R of the master cylinder 16. The reserve tank 52 functions to adjust the hydraulic pressure (fluid amount) of the hydraulic system of the brake device 10. Furthermore, auxiliary paths 56L and 56R communicating with the pressurizing chambers 42L and 42R of the motor cylinders 18L and 18R are connected to the reserve tank 52. The paths 54L and 54R and the auxiliary paths 56L and 56R join together before being connected to the reserve tank 52.

  In the path 54 connected to the reserve tank 52, the opening communicating with the pressurizing chamber 30 is formed close to the original position of the piston 26. As a result, when the pistons 26L and 26R advance from their original positions, that is, when the pistons 26L and 26R move even slightly, the opening is closed, and a path 54L is formed between the pressurizing chambers 30L and 30R and the reserve tank 52. , 54R are shut off. Further, the auxiliary route 56 is configured in substantially the same manner as the route 54 described above. That is, the auxiliary paths 56L and 56R are blocked between the pressurizing chambers 42L and 42R and the reserve tank 52 at the same time as the pistons 38L and 38R advance from their original positions.

  In such a brake device 10, master cylinder pressure sensors 58L, 58R, fail-safe valves 60L, 60R, brake pressure sensors (caliper pressure sensors) are provided in the main paths 33L, 33R in order from the pressurizing chambers 30L, 30R side. ) 62L and 62R are disposed. Further, brake valves (caliper valves) 64L and 64R are disposed in the paths 44L and 44R, and simulator valves 66L and 66R are disposed in the paths 46L and 46R.

  The fail-safe valve 60 is provided between the main path 33 and the connecting part of the path 44 and the connecting part of the path 46. When the solenoid 60a is excited under the control of the ECU 20, the fail-safe valve 60 communicates with the main path 33. Cut off. Similarly, under the control of the ECU 20, the brake valve 64 communicates or blocks the path 44 when the solenoid 64a is excited, and the simulator valve 66 communicates or blocks the path 46 when the solenoid 66a is excited.

  In FIG. 1, for the sake of simplicity, the signal lines connected from the master cylinder pressure sensor 58 and the brake pressure sensor 62 to the ECU 20 and the signal lines connected from the solenoids 60a, 64a, 66a to the ECU 20 are omitted. Yes.

  In the brake device 10 configured as described above, the operation information of the pedal 12 is normally detected by the pedal operation information detection unit 22 and input to the ECU 20 at the normal time. Then, the motor cylinder 18 is driven based on a command from the ECU 20, the braking force is generated by the braking force generator 14, and a braking operation is performed. That is, the brake device 10 is configured as a so-called brake-by-wire system that employs the by-wire technology.

  Therefore, at the normal time when the brake device 10 is driven and controlled as brake-by-wire (when the system is turned on), first, the brake valve 64 and the simulator valve 66 are opened under the control of the ECU 20, and the fail-safe valve 60 is closed. To do.

  When the driver operates the pedal 12 in this state, the hydraulic pressure generated in the pressurizing chamber 30 of the master cylinder 16 by the operation of the pedal 12 is given to the stroke simulator 13, and the reaction force is obtained by the stroke simulator 13. Can do. Note that the reaction force generated by the stroke simulator 13 can be corrected by the electric actuator 24 based on the pedaling force detected by the pedal operation information detection unit 22, for example, so that even better characteristics can be obtained.

  At the same time, operation information (stepping force and stroke) of the pedal 12 is input to the ECU 20 from the pedal operation information detection unit 22, and the motor cylinder 18 is driven and controlled by the ECU 20 based on the operation information. As a result, the hydraulic pressure generated in the motor cylinder 18 is applied to the braking force generation unit 14, and the braking force generation unit 14 generates braking force to brake the left wheel LW and the right wheel RW.

  On the other hand, when the brake device 10 is not driven and controlled as a brake-by-wire (when the system is off), for example, when the system is stopped when the ignition is off, the fail-safe valve 60 is first opened under the control of the ECU 20. Then, the brake valve 64 and the simulator valve 66 are closed (see FIG. 1).

  When the driver operates the pedal 12 in this state, the hydraulic pressure generated in the pressurizing chamber 30 of the master cylinder 16 by the operation of the pedal 12 is applied to the braking force generation unit 14 and is controlled by the braking force generation unit 14. Power is generated and the left wheel LW and the right wheel RW are braked. At this time, the reaction force to the pedal 12 can be obtained by the master cylinder 16.

  Thus, in the brake device 10, the reaction force at the pedal 12 when the system is on is applied by the stroke simulator 13. That is, the pedaling force and stroke characteristics of the pedal 12 reflect the characteristics of the cylinder mechanism 11 constituting the stroke simulator 13. Therefore, in the cylinder mechanism 11, for example, the stable characteristics that are substantially the same in the same vehicle type on which the brake device 10 is mounted and that do not change with time, and the characteristics of the stroke and the pedaling force are nonlinear, that is, at the start of the pedal 12 being depressed. It is important to have a characteristic that the operation torque (stepping rigidity) can be reduced, the operation torque (stepping rigidity) can be increased as the pedal 12 is depressed, and the driver can feel the pedal operation without feeling uncomfortable. .

  Then, next, the cylinder mechanism 11 which concerns on this embodiment is demonstrated. FIG. 2 is a schematic cross-sectional view along the axial direction of the cylinder mechanism 11 according to the present embodiment.

  As shown in FIG. 2, the cylinder mechanism 11 includes a cylindrical housing 70 and a piston 72 slidably held in the housing 70. The opening 70a on one end side (arrow X1 side) of the housing 70 is closed by inserting a plug (lid member) 74 having a communication hole 74a formed in the axial direction (arrow X direction in FIG. 2). Yes.

  The communication hole 74a opens (communicates) with a hole 74b having a diameter larger than that of the communication hole 74a in the direction of the arrow X2, and the piston 72 extends in the axial direction (the direction of the arrow X in FIG. 2). ) Is slidably inserted. In other words, the hole 74b functions as a cylinder for driving the piston 72 forward and backward, and hydraulic fluid (for example, brake fluid of the brake device 10) from the path 75 connected to the outer end surface of the plug 74 to the communication hole 74a. Is introduced, the hydraulic pressure of the hydraulic fluid is transmitted to the tip surface (operation surface) 72a of the piston 72. As a result, the piston 72 is retracted in the direction of the arrow X2 by the hydraulic pressure of the hydraulic fluid supplied from the communication hole 74a, or advanced in the direction of the arrow X1 by the urging force of the first and second spring members 82a and 84a described later. By being moved, a liquid chamber 73 into which hydraulic fluid is introduced is formed (defined) between the distal end surface 72a and the plug 74 (see FIGS. 8A and 8B).

  A slightly larger diameter recess 72b is opened on the surface of the piston 72 on the arrow X2 side, and a recess 72c having a smaller diameter than the recess 72b is opened on the bottom surface of the recess 72b.

  In the plug 74, the hole 74b that holds the piston 72 is formed as an inner peripheral surface of a cylindrical portion 74c that protrudes in the direction of the arrow X2. The outer peripheral surface of the cylindrical portion 74c is slidably held in a recess 76a of a transmission member 76 that partitions the inside of the housing 70 in the arrow X direction. The transmission member 76 has a bottomed cylindrical shape having the concave portion 76a that is recessed on the arrow X2 side, and has a flange portion 76b that is provided along the diameter direction from the peripheral portion of the concave portion 76a.

  A disc-shaped support member 78 is seated on the bottom of the recess 76a constituting the transmission member 76, and a support shaft (support bar) 80 oriented in the direction of the piston 72 (arrow X1 direction) is located at the center thereof. Is protruding. The support shaft 80 holds a first spring member 82a that urges the piston 72 toward the arrow X1 between the recess 72b of the piston 72.

  On the other hand, a second spring member 84a that urges the transmission member 76 to the arrow X1 side is disposed on the arrow X2 side of the flange portion 76b constituting the transmission member 76. The second spring member 84a is held at its axial end by a plug (lid member) 86 that closes the opening 70b on the other end side (arrow X2 side) of the housing 70 and the flange portion 76b. The diameter direction is held by the housing 70 and the transmission member 76. In the case of this embodiment, the spring constant of the second spring member 84a is set higher than that of the first spring member 82a.

  In the center of the plug 86, when the transmission member 76 is largely displaced to the arrow X2 side, a buffer member 88 is fitted to suppress abnormal noise and breakage due to bottom thrust on the plug 86. The buffer member 88 is formed of an elastic material such as rubber, for example.

  Here, the structure of the 1st and 2nd spring members 82a and 84a which urge the piston 72 is demonstrated with reference to FIGS. 3A is a cross-sectional view schematically showing the structure of the first spring member 82a, and FIG. 3B is a cross-sectional view schematically showing a state in which the first spring member 82a shown in FIG. 3A is contracted. FIG. 4 is a partially omitted cross-sectional perspective view along the axial direction of the cylinder mechanism 11. 5A is a perspective view of a disc spring 90 provided in the cylinder mechanism 11, and FIG. 5B is a front view of the disc spring 90 shown in FIG. 5A. The first spring member 82a and the second spring member 84a have substantially the same basic structure except that their inner and outer diameters, spring constants, holding forms, and the like are different. Therefore, the first spring member 82a will be specifically described below. The description of the second spring member 84a will be omitted.

  As shown in FIGS. 3A and 4, the first spring member 82 a (second spring member 84 a) has a plurality of disc springs 90 and 92 each having a truncated cone shape having an open top surface and a bottom surface. The support shaft 80 (in the case of the second spring member 84a, the transmission member 76) is inserted with the upper surfaces facing each other. That is, as shown in FIG. 3A, one disc spring 90 is arranged so that its conical shape is upward, and the other disc spring 92 is arranged so that its conical shape is downward (opposite to the disc spring 90). A plurality of sets of disc springs 90 and 92 are laminated (in the case of this embodiment, two sets are provided for the first spring member 82a and four sets are provided for the second spring member 84a). Note that the disc spring 90 and the disc spring 92 have the same shape, spring constant, and the like except that the arrangement directions are different.

  As shown in FIGS. 5A and 5B, such a disc spring 90 (92) has a truncated cone shape whose upper surface and bottom surface are open, and is formed along a radial direction from the inner peripheral side toward the outer peripheral side. And an outer slit 96 that is a cut formed along the radial direction from the outer peripheral side toward the inner peripheral side. As shown in FIG. 5A, in the case of the present embodiment, 22 inner slits 94 and 22 outer slits 96 are formed, but the number of the slits depends on the use conditions of the disc spring 90 and the like. Of course, it is possible to change the number of the springs 90 so that a desired spring characteristic can be obtained from the relationship with the plate thickness, inner and outer diameters, etc., for example, one inner slit 94 and one outer slit 96, respectively. Also good.

  FIG. 6 is a graph showing the relationship between the load (load) of the disc spring 90 and the displacement. In FIG. 6, line A <b> 1 indicates the spring characteristics at the slit portion (inner slit 94 or outer slit 96) of the disc spring 90, and line A <b> 2 indicates the disc spring portion (plate portion) without the disc spring 90 slit. The line A3 shows the spring characteristic of the whole disc spring 90 in which the spring characteristic at the slit portion shown by the line A1 and the spring characteristic at the disc spring portion shown by the line A2 are combined. Yes.

  As shown in FIG. 6, the slit portion does not function as a disc spring, in other words, does not have a spring characteristic as a disc spring, and has a linear characteristic similar to a cantilever (line A1). reference). Moreover, the said disc spring part has the characteristic which draws the curve of the quadratic curve which is the characteristic of a disc spring (refer line A2). And the disc spring 90 provided with these slit parts and a disc spring part has a large displacement as a whole, and also has the non-linear spring characteristic of the quadratic curve which is the characteristic of a disc spring (refer line A3). .

  Therefore, in the cylinder mechanism 11 according to the present embodiment, as shown in FIG. 3B, when the first spring member 82a is contracted by the pressing action of the piston 72, the disc springs 90 and 92 generate a sufficiently large amount of displacement. can do. Therefore, according to the present embodiment, it is possible to obtain a desired displacement amount while reducing the number of stacked disc springs 90 (92) as compared to the conventional cylinder mechanism using a disc spring without slits. It becomes. In this case, in the 1st spring member 82a (2nd spring member 84a), since the bottom face (upper surface) of the disc springs 90 and 92 which comprise the said set is arrange | positioned mutually facing, the upper surface of each disc spring The side is not buried in the bottom side, and a sufficient amount of displacement can be obtained with a smaller number of sheets.

  In the cylinder mechanism 11 according to the present embodiment, since the disc spring 90 (92) having the inner slit 94 and the outer slit 96 and capable of obtaining a large displacement amount is used, for example, as shown in FIG. Even if each disc spring 90 is configured as the first spring member 82b or the second spring member 84b stacked in the same direction, a desired displacement amount can be obtained with a relatively small number of stacked layers. That is, as shown in FIG. 7, when the disc springs 90 (92) are stacked in the same direction, the conventional disc springs without slits have stable spring characteristics, but the displacement amount is insufficient, which is a practical problem. However, in the case of this embodiment, by using the disc spring 90 having the inner slit 94 and the outer slit 96, a sufficient amount of displacement can be secured and desired spring characteristics can be obtained. It becomes like this.

  Basically, in the cylinder mechanism 11 configured as described above, when hydraulic fluid is supplied from the path 75 into the communication hole 74a and the hydraulic pressure of the hydraulic fluid is transmitted to the tip surface 72a of the piston 72, The piston 72 moves backward (slids) in the direction of the arrow X2 against the urging force of the first spring member 82a (first spring member 82b). Along with the retraction of the piston 72, a liquid chamber 73 into which hydraulic fluid is introduced is formed between the distal end surface 72a and the plug 74 (see FIG. 8A). The hydraulic fluid is, for example, the hydraulic pressure from the master cylinder 16 in the case of the stroke simulator 13 constituting the brake device 10, and in this case, the path 75 corresponds to the path 46 (see FIG. 1).

  Subsequently, when the piston 72 is further retracted in the direction of the arrow X2 by the hydraulic pressure of the hydraulic fluid and the piston 72 comes into contact with the support member 78 (see FIG. 8A) (see FIG. 8A), this time, via the transmission member 76. The biasing force of the second spring member 84a (second spring member 84b) acts on the piston 72, and the piston 72 moves backward (slids) in the direction of the arrow X2 against the biasing force of the second spring member 84a. (See FIG. 8B).

  In this case, in the cylinder mechanism 11 according to the present embodiment, the disc spring 90 (92) having a nonlinear quadratic curve characteristic and having a sufficient amount of displacement due to the formation of the inner slit 94 and the outer slit 96. Are stacked to form the first spring member 82a and the second spring member 84a. For this reason, when each disc spring 90 (92) bends, in addition to the repulsive force by each disc spring 90, the sliding resistance between the disc springs 90 increases so that each disc spring 90 contracts. In addition, a sufficient amount of displacement is secured even with a relatively small number of stacked sheets.

  Therefore, according to the stroke simulator 13 according to this embodiment to which such a cylinder mechanism 11 is applied, for example, the pedal force (reaction force) of the pedal 12 can be increased as the stroke of the pedal 12 increases in the brake device 10. (See line B1 in FIG. 9). Further, when the pedal 12 is returned, the sliding resistance between the disc springs 90 and 92 decreases as the disc springs 90 and 92 extend, and the disc springs 90 and 92 are sufficiently contracted. For this reason, at the time of the return operation of the pedal 12, a hysteresis characteristic is added to the characteristics of the stroke and the depression force (see line B2 in FIG. 9). Therefore, in the stroke simulator 13, the characteristics of the stroke and the pedaling force are optimal non-linear as shown in FIG. 9, and it is possible to give the driver a feeling of pedal operation without feeling uncomfortable. In addition, since the number of disc springs 90 (92) used is effectively reduced, the stroke simulator 13 can be reduced in size and weight, and the cost can be reduced.

  Further, in the disc spring 90 (92), the slit portion (the inner slit 94 and the outer slit 96) can obtain linear characteristics similar to a cantilever (see the line A1 in FIG. 6), so that the stroke simulator 13 Then, the non-linear characteristic and the linear characteristic can be mutually used, and the range of setting of the pedal characteristic can be expanded.

  In the case of the present embodiment, the number of stacked plate springs 90 is effectively reduced by using the disk springs 90 (92) in which the inner slits 94 and the outer slits 96 are formed. For this reason, it is possible to effectively prevent the variation in the characteristics of the disc springs 90 from increasing due to an increase in the number of stacked layers, and it is possible to obtain stable spring characteristics while suppressing individual differences between products.

  Further, the cylinder mechanism 11 (stroke simulator 13) includes, in addition to the first spring members 82a and 82b, second spring members 84a and 84b having a larger spring constant than the first spring members 82a and 82b. By urging the piston 72, the characteristics of the stroke and the pedaling force of the pedal 12 can be further improved.

  In the above embodiment, the disc spring 90 (92) has been described as having the inner slit 94 and the outer slit 96. However, for example, only the inner slit 94 or only the outer slit 96 can be provided.

  Further, the application example of the cylinder mechanism 11 according to the present invention is not limited to the stroke simulator 13, and it is needless to say that the brake device 10 is not limited to that shown in FIG. 1.

  As described above, the present invention has been described with the embodiment. However, the present invention is not limited to this, and it is naturally possible to adopt various configurations without departing from the gist of the present invention.

It is a block circuit diagram of a brake device carrying a stroke simulator to which a cylinder mechanism according to an embodiment of the present invention is applied. It is a schematic sectional drawing in alignment with the axial direction of the cylinder mechanism which concerns on one Embodiment of this invention. 3A is a cross-sectional view schematically showing the structure of the first spring member, and FIG. 3B is a cross-sectional view schematically showing a state in which the first spring member shown in FIG. 3A is contracted. FIG. 3 is a partially omitted cross-sectional perspective view along the axial direction of the cylinder mechanism shown in FIG. 2. 5A is a perspective view of a disc spring provided in the cylinder mechanism shown in FIG. 2, and FIG. 5B is a front view of the disc spring shown in FIG. 5A. It is a graph which shows the relationship between the load and displacement of a disc spring shown in FIG. It is a perspective view which shows the other laminated structure of the 1st or 2nd spring member provided in the cylinder mechanism shown in FIG. FIG. 8A is a schematic cross-sectional view showing a state in which the piston is retracted by a hydraulic pressure and a liquid chamber is formed in the cylinder mechanism shown in FIG. 2, and FIG. 8B is a further piston retracted from the state shown in FIG. 8A. It is a schematic sectional drawing which shows the state moved. It is a graph which shows the relationship between the stroke of a pedal, and a pedal effort.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Brake apparatus 11 ... Cylinder mechanism 12 ... Pedal 13L, 13R ... Stroke simulator 26L, 26R, 38L, 38R, 72 ... Piston 70 ... Housing 72a ... End surface 73 ... Liquid chamber 74, 86 ... Plug 74a ... Communication hole 76 ... Transmission member 78 ... support member 80 ... support shafts 82a and 82b ... first spring members 84a and 84b ... second spring members 90 and 92 ... disc spring 94 ... inner slit 96 ... outer slit

Claims (2)

A housing;
A piston that is slidably held in the housing and forms a fluid chamber through which hydraulic fluid is guided;
A cylinder mechanism comprising a disc spring for biasing the piston toward the liquid chamber,
The disc mechanism is characterized in that a cut along the radial direction is formed in the disc spring. A stroke simulator connected to a master cylinder and generating a reaction force on a brake pedal by a hydraulic pressure generated by the master cylinder,
The stroke simulator includes a housing,
A piston that is slidably held in the housing and that is driven forward and backward by the hydraulic pressure generated by the master cylinder to form a fluid chamber into which hydraulic fluid is guided;
A disc spring having a notch along a radial direction and biasing the piston toward the liquid chamber;
A stroke simulator comprising:

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