JP3605489B2 - Load response type brake hydraulic control valve - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a load response type brake hydraulic pressure control valve used for controlling a brake hydraulic pressure of an automobile, a motorcycle or the like, and more particularly to an input chamber communicating with an output port of a master cylinder and an output chamber communicating with a wheel brake. And a valve piston that controls the opening and closing between the two chambers so that the oil pressure in the input chamber is proportionally reduced and transmitted to the output chamber, and the valve piston is fixed to determine the pressure reduction start point of the valve piston. The pressure adjustment spring that urges in the direction and the nut plate that supports the pressure adjustment spring on the side opposite to the valve piston are housed, and the load detection shaft screwed to this nut plate is freely rotatable on the casing and cannot move in the axial direction. The present invention relates to an improvement in which a load detection shaft is rotated forward and reverse so as to advance and retreat a nut plate with respect to a pressure adjusting spring in accordance with an increase or decrease in a loaded weight of a vehicle.
[0002]
[Prior art]
Such a load response type brake hydraulic control valve is already known, for example, as disclosed in Japanese Utility Model Publication No. 1-3578.
[0003]
[Problems to be solved by the invention]
In general, in such a load response type brake hydraulic control valve, the amount of advance and retreat of the nut plate with respect to the pressure adjusting spring is smaller than the amount of rotation of the load detection shaft due to a change in the loaded weight of the vehicle. The spring constant of the pressure adjusting spring is set to be relatively large so that the load of the pressure adjusting spring is largely changed according to the displacement. For this reason, when the load on the wheels is drastically reduced due to heavy bounce, such as when the vehicle is traveling on rough roads, the nut plate retreats greatly and the pressure adjusting spring is fully extended, and as a result, the pressure adjusting spring comes into contact with the valve piston. It may play with the nut plate. In such a state, since the valve-opening force of the pressure adjusting spring is not applied to the valve piston, when braking is performed, the pressure-reducing action of the valve piston starts from the beginning, and the braking response is somewhat reduced.
[0004]
The present invention has been made in view of such circumstances, even when the load on the wheels is drastically reduced and the nut plate is largely retracted, play of the pressure adjusting spring is prevented to secure a load of a predetermined minimum value, Accordingly, it is an object of the present invention to provide the load response type brake hydraulic control valve having a good braking response by delaying the pressure reducing operation start point of the valve piston to a necessary minimum.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides, in a casing, an input chamber communicating with an output port of a master cylinder and an output chamber communicating with a wheel brake, and reducing the hydraulic pressure of the input chamber proportionally. A valve piston that controls the opening and closing of the two chambers so that the pressure is transmitted to the output chamber, a pressure regulating spring that biases the valve piston in a certain direction to determine the pressure reduction start point of the valve piston, and a valve spring on the side opposite to the valve piston. A nut plate supporting the pressure adjusting spring is accommodated, and a load detection shaft screwed to the nut plate is rotatably supported on the casing so as to be immovable in the axial direction. regulating a load sensing axis so as to advance and retreat with respect to pressure springs so as to reverse rotation, the load-responsive brake pressure control valve, between the valve piston and the nut plate, and pressure control spring, load on the wheel And an auxiliary spring capable of imparting a load to extend the pressure regulating spring so as to suppress the play when trying to play the pressure control spring in the valve piston and the nut plates to each other in series by depleted, and the set load of the auxiliary springs A first feature is that the pressure regulating spring is interposed smaller than that of the pressure regulating spring .
[0006]
Thus, when the load on the wheels is drastically reduced due to severe bounce, etc., the nut plate retreats greatly and the pressure adjusting spring tries to play between the valve piston and the nut plate. In addition to suppressing it, it is possible to apply a minimum necessary load to it. Therefore, when braking is performed in such a state, a predetermined minimum pressure-reducing action start point is given to the valve piston, and the brake hydraulic pressure is not reduced to that point, so that braking responsiveness can be improved .
[0007]
According to the present invention, in addition to the above features, a retainer having a tubular portion housed in the pressure regulating spring is interposed between the nut plate and the pressure regulating spring, and an auxiliary spring is contained in the tubular portion. This is a second feature.
[0008]
According to this feature, the concentric arrangement of the pressure adjusting spring and the auxiliary spring can contribute to downsizing of the brake hydraulic control valve.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.
[0010]
First, a first embodiment of the present invention shown in FIGS. 1 to 5 will be described. FIG. 2 shows a brake device for an automobile. In the drawing, M is a tandem type master cylinder which is actuated by the brake pedal 1, a first output port P ₁ via the first oil passage L ₁ of the left front wheel brake Bfl wheel cylinders, and its second output right front wheel brake Bfr wheel cylinder to the port P ₂ through the second oil passage L ₂ are respectively connected. A third oil passage L ₃ and a fourth oil passage L ₄ branching from the first oil passage L ₁ and the second oil passage L ₂ , respectively, are piped to cross each other on the left and right sides, and a right rear part of the third oil passage L _3. wheel cylinders of the wheel brakes Brr are also left rear wheel brake Brl the wheel cylinders are respectively connected to the fourth oil passage L _4. And as to intervene in the middle of the third oil passage L ₃ and the fourth oil passage L _4, the load-responsive brake pressure control valve V of the present invention is provided.
[0011]
The brake hydraulic pressure control valve casing 3 of V is formed of a flange ₃ 1 a, _{3 2} the first and second casing half having a respective ₃ 1, _{3 2} facing each their flanges ₃ 1 a, 3 ₂ a is joined by a plurality of bolts 20. At that time, the first casing half 3 ₁ circular positioning recess 21 formed in the joint end face of the circular positioning tubular portion 22 formed in the second joining end face of the casing half 3 ₂ via the seal member 24 Mated.
[0012]
The first casing 3, a first pressure reducing valve 2 ₁ and the second pressure reducing valve 2 ₂ is provided to intervene respectively in the third oil passage L ₃ and the fourth oil passage L _4, also the second casing half 3 ₂ It is pressure control spring 25 to determine the action of vacuum starting point of the pressure reducing valve 2 _1, 2 ₂ are provided.
[0013]
Since the structure of the first and second pressure reducing valve 2 _1, 2 ₂ are identical, for the first pressure reducing valve 2 ₁ structure only, with reference to FIG.
[0014]
The first casing half 3 _1, inlet and outlet ports 4, 5, they enter, enter communicating respectively to the outlet ports 4, 5, and output chambers 6 and 7 are provided, the third oil passage to the inlet port 4 upstream of the L ₃ (in the second pressure reducing valve 2 ₂ upstream side of the fourth oil passage L ₄₎ is connected, also in the downstream side (second pressure reducing valve 2 ₂ Doaburaro L ₃ to the outlet port 5 downstream side of the fourth oil passage L ₄₎ is connected.
[0015]
Each of the input and output chambers 6 and 7 has a cylindrical shape. The output chamber 7 is formed to have a smaller diameter than the input chamber 6 and is coaxially connected to one end of the input chamber 6 via an annular step portion 8. Are arranged as follows.
[0016]
The first casing half 3 _1, Furthermore, the input chamber 6 with continuous via an annular stepped portion on the outer end, the large diameter of the mounting hole 26 which opening is provided on the bottom surface of the positioning recess 21, guide member 9 is fitted via a seal member 23.
[0017]
A valve seat member 11 formed of an elastic material such as rubber is mounted in the input chamber 6 so as to abut on the annular step portion 8. This valve seat member 11 is provided with a valve hole 12 having a diameter smaller than that of the output chamber 7, which communicates between the output chambers 6 and 7 at the center thereof, and has an annular arrangement on an end face facing the input chamber 6. A plurality of projections 13 are formed. Further, a one-way seal lip 14 is formed on the outer periphery of the valve seat member 11 and extends in a direction opposite to the annular step portion 8 and is in close contact with the inner peripheral surface of the input chamber 6.
[0018]
A valve piston 15 which cooperates with the valve seat member 11 to communicate between the input and output chambers 6 and 8 and shuts off is disposed over the input and output chambers 6 and 7. That is, the valve piston 15 includes a valve rod 16 and a piston-shaped valve portion 18 integrally connected to one end of the valve rod via a small-diameter neck portion 17. 11, a valve rod 16 is disposed in the input chamber 6 and is slidably supported by a guide member 9 via a seal member 10. It is arranged in. The valve hole 18 can be opened and closed by separating and seating the valve portion 18 on and from the valve seat member 11. The valve portion 18 is provided with a through hole 19 communicating between the front and rear end faces.
[0019]
Thus the first and second pressure reducing valve 2 _1, 2 ₂ are constructed, their guide members 9, 9 have a common retainer plate 27 which is held by the positioning tube 22 with the positioning recess within 21 departure from the first casing half _{3 1} of the mounting hole 26, 26 is prevented.
[0020]
First and second pressure reducing valve 2 _1, 2 ₂ of the valve stem 16 extends the end to the second casing half 3 in ₂ through the guide member 9 and the press plate 27. Inside of the second casing half 3 ₂ is a cylindrical chamber 28 having a bottom, in the center of its bottom wall, rotatable load sensing shaft 29 therethrough via the bush 30 and the seal member 31 It is supported by The load detection shaft 29 has a portion that protrudes into the cylindrical chamber 28 as an adjusting screw portion 29a, and a flange 29b that is in contact with the bottom surface of the cylindrical chamber 28 is formed at the base end.
[0021]
In the cylindrical chamber 28, and the adjusting fixing plate 32 which fits rotatably on the inner circumferential surface while being in contact on its bottom surface, a nut plate 33 screwed to the adjusting screw portion 29a, both the pressure reducing valve 2 _1, 2 A pressing plate 34 slidably fitted to the inner surface of the cylindrical chamber 28 while abutting on the end of the _second valve rod 16, and a pressing plate 34 interposed between the nut plate 33 and the pressing plate 34 to connect the pressing plate 34 to the valve rod 16. A plurality (two in the illustrated example) of pressure adjusting springs 25 biased toward the housing are housed. A connection pin 50 is erected on the adjustment fixed plate 32 in parallel with the load detection shaft 29. The connection pin 50 is slidably fitted in a pin hole 51 of the nut plate 33, and A connecting means 35 for connecting the adjustment fixing plate 32 and the nut plate 33 to each other in the rotational direction while allowing the axial displacement is provided.
[0022]
A retainer 36 is interposed between the nut plate 33 and each pressure adjusting spring 25. The retainer 36 has a cylindrical portion 36 a disposed in the corresponding pressure adjusting spring 25, and an auxiliary spring 52 for urging the retainer 36 toward the pressure adjusting spring 25 is accommodated therein. Thus, the pressure adjusting spring 25 and the auxiliary spring 52 are interposed between the pressing plate 34 and the nut plate 33 in series. The set load and the spring constant of the auxiliary spring 52 are set much smaller than those of the pressure regulating spring 25. Thus, in a state where a predetermined set load is applied to the pressure adjusting spring 25, the retainer 36 is sandwiched between the pressure adjusting spring 25 and the nut plate 33 by sufficiently contracting the auxiliary spring 52. . In addition, since the cylindrical portion 36a of the retainer 36 accommodating the auxiliary spring 52 is arranged in the pressure adjusting spring 25, the pressure adjusting spring 25 and the auxiliary spring 52 can be arranged concentrically and double, and the brake hydraulic pressure control valve V Can be made more compact.
[0023]
A lever 37 is fixed to an outer end of the load detection shaft 29 protruding outside the cylindrical chamber 28 by a nut 38. Temporary fixing means 39 which can temporarily fix the load detection shaft 29 to the casing 3 at a predetermined position via the lever 37 from the time of assembling the brake hydraulic pressure control valve V to the time of mounting on the vehicle is provided. The temporary fixing means 39 includes a locking hole 40 bored in the predetermined positions of the second casing half 3 ₂ of the bottom wall, the temporary fixing screw 41 screwed into the stop hole 40 through the lever 37 Consists of
[0024]
The second circumferential wall of the casing half 3 _2, a portion with an adjacent portion of the peripheral surface of the adjusting fixing plate 32 so as to a thin wall 42a, the recess 42 is formed, in the regulation fixing plate 32 and the thin walls 42a By caulking 43, the adjustment fixing plate 32 is fixed to the casing 3. Thereby, the fixing means 44 of the adjustment fixing plate 32 is configured.
[0025]
The second circumferential wall of the casing half 3 ₂ is formed with a pair of mounting bosses 45, by using these, as shown in FIG. 1, the brake hydraulic pressure control valve V is mounted to the vehicle frame 46 . The lever 37 is linked and connected to a suspension arm 48 of the rear wheel Wr via a link 47.
[0026]
Thus, when the load detection shaft 29 rotates in the direction of the arrow 49 via the link 47 and the lever 37 with the upward swing of the suspension arm 48 due to an increase in the load weight of the vehicle, the adjusting screw portion 29a is turned on. The load of the pressure adjusting spring 25 is increased by advancing the nut plate 33 toward the pressing plate 34, and conversely, the load detection shaft 29 rotates in the direction indicated by the arrow 49 with the downward swing of the suspension arm 48. Then, the adjusting screw portion 29a retreats the nut plate 33 to the side opposite to the pressing plate 34 to reduce the set load of the pressure adjusting spring 25.
[0027]
Next, the operation of this embodiment will be described.
[0028]
When assembling the brake hydraulic pressure control valve V, firstly the first casing half _{3 1} First, mounting the second pressure reducing valve ₂ 1, _{2 2} and the presser plate 27.
[0029]
On the other hand, the second casing half 3 _2, by mounting the load sensing axis 29 as shown in FIG. 4, which in mounting the lever 37, the lever 37, the temporary fixing screws 41 in place of the casing 3 Fix it. Next, the adjusting and fixing plate 32 having the connecting pin 50 is fitted to the bottom of the cylindrical chamber 28 of the second casing 3, and the nut plate 33 is screwed into the screw portion 29 a of the load detection shaft 29, and the nut plate 33 is moved from the nut plate 33 to the second. (2) The distance to the upper end surface of the casing 3 is adjusted to a predetermined value d, and the adjustment fixing plate 32 is fixed to the casing 3 by caulking 43 the thin wall 42a of the concave portion 42 to maintain the state. At this time, a sufficient space is secured between the nut plate 33 and the adjustment fixing plate 32, and between the nut plate 33 and the flange 29b of the load detection shaft 29 to allow the load detection shaft 29 to rotate in the direction indicated by the arrow 49. It has become so. Thereafter, on the nut plate 33, which is machined to the proper dimension extension spring 52, placing the retainer 36 and pressure control spring 25, from the fitted the pressing plate 34 to the cylinder chamber 28, the first and second casing 3 ₁ , mutually bolted to _{3 2.} Thus, a set load of the pressure control spring 25 is set to a predetermined value corresponding to the standard loading weight of the vehicle, the pressure reducing valve 2 _1, 2 ₂ of the pressure reducing action start point A (see FIG. 5) is determined precisely.
[0030]
Further, according to the caulking 43 of the thin wall 42a, the adjustment fixing plate 32 can be securely fixed while ensuring the airtightness of the cylindrical chamber 28.
[0031]
In the brake hydraulic control valve V thus configured, the lever 37 is fixed to a fixed position of the casing 3 by a temporary fixing screw 41 until the brake hydraulic control valve V is mounted on the vehicle. Therefore, it is possible to prevent the set load of the pressure adjusting spring 25 from being disordered due to the blind movement of the load detection shaft 29 during handling such as transportation.
[0032]
Finally, the brake hydraulic control valve V is mounted on the frame 46 of the automobile, the temporary fixing screw 41 is removed, and the lever 37 is connected to the link 47 connected to the suspension arm 48 of the rear wheel Wr. Thus, when the suspension arm 48 swings upward due to an increase in the load of the vehicle, the load detection shaft 29 rotates in the direction of arrow 49 to advance the nut plate 33 toward the pressing plate 34, so that the pressure adjustment is performed. On the contrary, when the suspension arm 48 swings downward due to a decrease in the weight of the vehicle, the load detection shaft 29 rotates in the direction indicated by the arrow 49 and the nut plate is rotated. Since the 33 is retracted to the side opposite to the pressing plate 34, the set load of the pressure adjusting spring 25 can be reduced.
[0033]
If operating the master cylinder M depress the brake pedal 1, together with the first output port output hydraulic pressure from P ₁ is fed directly to the left front wheel brake Bfl via the first oil passage L _1, the third oil passage L ₃ through, i.e. is supplied to the right rear wheel brake Brr via the first pressure reducing valve 2 _1. Also with the output hydraulic pressure from the second output port P ₂ is fed directly to the right front wheel brake Bfr through the second oil passage L _2, via the fourth oil passage L _4, namely via the second pressure reducing valve 2 ₂ It is supplied to the left rear wheel brake Brl.
[0034]
Thisゝthe first and second pressure reducing valve 2 _1, 2 ₂ operates as follows. Initially operation of the master cylinder M, the first and second pressure reducing valve ₂ 1, _{2 2} are in open state, the first and second output port _P 1, the _{P 2} first and second pressure reducing valve ₂ 1, 2 ₂ hydraulic pressure supplied to each of the input chamber 6 directly transmitted via the Kakuben'ana 12 to the output chamber 7. When the hydraulic pressure in the input chamber 6 is increased to a predetermined value, the cross-sectional area of the hydraulic by the downward valve closing force in Fig. 3 (a valve stem 16, the diameter D ₁ which is supported on the guide member 9 parts acting on the valve piston 15 And the output chambers 6 and 7 are multiplied by the hydraulic pressure), and overcomes the set load of the pressure adjusting spring 25 to move the valve piston 15 in the valve closing direction, and the valve portion 18 is seated on the valve seat member 11 to close the valve. The hole 12 is closed, thereby shutting off the space between the input and output chambers 6 and 7.
[0035]
Thisゝa, when an effective seal diameter to the valve unit 18 the valve seat member 11 and D _2, the pressing force valve piston in turn multiplied by the hydraulic pressure in the output chamber 7 to the area of a circle the effective sealing diameter D ₂ and the diameter The pressing force obtained by multiplying the area difference between the circles of the diameters D ₁ and D ₂ (D ₁ <D ₂ ) by the oil pressure of the input chamber 6 becomes the valve opening force of the valve piston 15. Therefore, when the oil pressure in the input chamber 6 further increases, the valve opening force by the oil pressure in the input chamber 6 overcomes the valve closing force by the oil pressure in the output chamber 7 to push back the valve piston 15 in the valve opening direction, and the valve portion 18 Is separated from the valve seat member 11 and the chambers 6 and 7 are again electrically connected. As a result, the increased hydraulic pressure in the input chamber 6 is supplied to the output chamber 7, and when the valve closing force exceeds the valve opening force, the valve piston 15 closes again and shuts off between the two chambers 6, 7. Thereafter, a similar operation is the first and second pressure reducing valve by repeated fast 2 _1, 2 _2, the first and second ports P _1, the output pressure of the P ₂ of the master cylinder M proportionally reduced pressure To the left and right rear wheel brakes Brr, Brl. Further, as described above, since the load of the pressure adjusting spring 25 is adjusted to increase or decrease according to the increase or decrease of the loaded weight of the vehicle, the depressurization start points of the left and right rear wheel brakes Brr, Brl are set as shown in FIG. The state changes from A to B and C, and the left and right rear wheel brakes Brr and Brl can be operated efficiently.
[0036]
By the way, in order to make the brake hydraulic control valve V compact, the swing of the suspension arm 48 is greatly reduced and transmitted to the nut plate 33, and the pressure adjusting spring 25 is moved in accordance with a relatively small displacement of the nut plate 33. The spring constant of the spring 25 is set relatively large so as to change the load as desired. For this reason, when the suspension arm 48 swings largely downward due to heavy bounding of the left and right rear wheels when the vehicle is traveling on a rough road, the nut plate 33 largely retreats due to the rotation of the load detection shaft 29 in the direction opposite to the arrow 49, The nut plate 33 and the pressure adjusting spring 25 may be separated from each other. In such a case, the auxiliary spring 52 having a small set load and a small spring constant is stretched so as to fill the gap, so that the pressure adjusting spring 25 is required. A minimum load can be applied. Therefore, even during braking in that state, as shown in FIG. 5, since the rear wheel brake hydraulic pressure does not decrease until the predetermined minimum pressure reducing operation start point D is reached, the right and left rear wheel brakes Brl, Brr are good. Responsiveness can be secured.
[0037]
Next, when the pedaling force on the brake pedal 1 is released to return the master cylinder M to the inoperative state, the left and right front wheel brakes Bfl, Bfr are immediately released from the braking hydraulic pressure. On the other hand, in the pressure reducing valve 2 _1, 2 _2, input occurs with the low oil pressure of the input chamber 6, the pressure difference between the output chamber 6, the one-way seal lip 14 of the valve seat member 11 radially inwardly The hydraulic pressure shifts from the output chamber 7 side to the input chamber 6 through the gap due to the bending to form a gap between the input chamber 6 and the inner peripheral surface of the input chamber 6. As a result, when the output chamber 7 approaches the pressure of the input chamber 6, the valve piston 15 opens with the elastic force of the pressure adjusting spring 25. Thus, the left and right rear wheel brakes Brl, Brr are also released from the braking hydraulic pressure.
[0038]
First output port P ₁ or the oil passage of the second one of the lines of the output port P ₂ of the master cylinder M, for example, failure in the fourth oil passage L ₄ it is assumed that occurs, during braking in this case, the 1 and hydraulic pressure is generated only in the third oil passage L _1, L _3, since only the first pressure reducing valve 2 ₁ will operate, (in the illustrated example two) plurality of set load of the pressure regulating spring 25 of the all join first pressure reducing valve 2 ₁ of one of the valve piston 15, pressure reducing action starting point of the first pressure reducing valve 2 ₁ comes to delayed significantly from the normal. Therefore, it is possible to suppress the pressure reduction of the hydraulic pressure of the right rear wheel brake Brr that normally operates as much as possible, and to compensate for the insufficient braking force due to the above-mentioned failure.
[0039]
6 and 7 show a second embodiment of the present invention. Casing 3 of the load-responsive brake pressure control valve V, together with the first and second pressure reducing valve 2 _1, 2 ₂ is mounted, a casing body 3a having a cylindrical chamber 28 having an open lower surface, of the cylindrical chamber 28 A lid 3b joined to the casing body 3a by bolts 53 to close the open surface is provided, and a load detection shaft 29 is attached to the center of the lid 3b. A thin annular wall 54 is integrally protruded from the lower surface of the adjusting and fixing plate 32 rotatably fitted to the cylindrical chamber 28, and a circular pedestal 55 is rotatably fitted to the inner periphery thereof. It is formed integrally on the upper surface of the body 3b. By caulking the annular wall 54 to the pedestal 55, the adjustment fixing plate 32 is fixed. In addition, the first and second pressure reducing valve ₂ 1, _{2 2,} the guide member 9 is secured by a clip 56 to the casing body 3a. Since other configurations are the same as those of the previous embodiment, the same reference numerals as in the previous embodiment denote the same parts in the drawings, and a description thereof will be omitted.
[0040]
At the time of assembling the brake hydraulic pressure control valve V, as shown in FIG. 7, the nut plate 33 is rotated while the load detection shaft 29 is fixed to a predetermined position of the lid 3 b by the temporary fixing means 39 while rotating the nut plate 33. After adjusting the distance h between the body 3a and the load detection shaft 29 to a predetermined value, the adjustment fixing plate 32 is fixed by the above-described caulking 43, so that when the assembly of the brake hydraulic control valve V is completed, As in the previous embodiment, a set load corresponding to the standard load weight of the vehicle can be accurately applied to the pressure adjusting spring 25.
[0041]
The present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the scope of the gist. For example, a load-responsive brake pressure control valve V, may be configured individually to the first and second pressure reducing valve 2 _1, 2 every _2.
[0042]
【The invention's effect】
As described above, according to the first aspect of the present invention, between the valve piston and the nut plate, the pressure adjusting spring tries to play between the valve piston and the nut plate due to a sharp decrease in the load on the wheel. Sometimes, an auxiliary spring that can extend and apply a load to the pressure adjusting spring to suppress the play is interposed in series with each other , and the set load of the auxiliary spring is set smaller than that of the pressure adjusting spring, so that it is severe. Even if the load on the wheels is drastically reduced due to bouncing, etc., and the nut plate retreats greatly and the pressure regulating spring tries to play between the valve piston and the nut plate, the pressure of the pressure regulating spring is increased by the action of the auxiliary spring that extends to suppress the play. along with suppressing play, it can give the minimum required load, therefore, at the time of braking in this state, it gives a predetermined minimum vacuum action starting point on the valve piston It is possible to improve the damping response.
[0043]
According to the second feature of the present invention, a retainer having a cylindrical portion housed in the pressure adjusting spring is interposed between the nut plate and the pressure adjusting spring, and the auxiliary spring is stored in the cylindrical portion. Therefore, the pressure adjusting spring and the auxiliary spring can be arranged concentrically and doublely, which can contribute to downsizing of the brake hydraulic control valve.
[Brief description of the drawings]
FIG. 1 is a rear view of a main part of an automobile equipped with a load response type brake hydraulic control valve according to a first embodiment of the present invention. FIG. 2 is a brake hydraulic circuit diagram of an automobile equipped with the above-described brake hydraulic control valve. FIG. 4 is an enlarged sectional view of a main part of the brake hydraulic control valve. FIG. 4 is an explanatory view of the brake hydraulic control valve at the time of adjusting the set load of a pressure adjusting spring. FIG. 5 is a characteristic diagram of the brake hydraulic control valve. FIG. 7 is a schematic diagram of a brake hydraulic circuit similar to FIG. 2 showing a second embodiment of the present invention. FIG. 7 is an explanatory diagram of the brake hydraulic control valve at the time of adjusting the set load of a pressure adjusting spring.
Brl: Left rear wheel brake as a wheel brake Brr: Right rear wheel brake as a wheel brake M: Master cylinder P _1: Output port (first output port)
P ₂ ··· Output port (second output port)
V ···· Load-responsive brake hydraulic control valve 3 ····· Casing 6 ····· Input chamber 7 ····· Output chamber 15 ···· Valve piston 25 ···· Pressure adjustment Spring 29: Load detection shaft 33: Nut plate 36: Retainer 36a: Cylindrical portion 52: Auxiliary spring

Claims (2)

The casing (3) to form an output port (P _1, P ₂₎ to communicate the input chamber of the master cylinder (M) and (6), wheel brakes (Brl, Brr) output chamber communicating with the (7) At the same time, a valve piston (15) for controlling the opening and closing of the two chambers (6, 7) so as to proportionally reduce the hydraulic pressure of the input chamber (6) and transmit the pressure to the output chamber (7), and the valve piston (15) A) a pressure regulating spring (25) for urging the pressure regulating action in a certain direction in order to determine the pressure reducing action start point, and a nut plate (33) for supporting the pressure regulating spring (25) on the side opposite to the valve piston (15). And a load detection shaft (29) screwed to the nut plate (33) is supported by the casing (3) so as to be rotatable and immovable in the axial direction, and the nut plate ( 33) Load detection to move the pressure spring (25) forward and backward (29) was to be reverse rotation, the load-responsive brake pressure control valve,
A pressure regulating spring (25) is provided between the valve piston (15) and the nut plate (33), and a pressure regulating spring (25) is provided between the valve piston (15) and the nut plate (33) due to a sharp decrease in the load on the wheels. When an attempt is made to play, an auxiliary spring (52) that extends to apply a load to the pressure adjusting spring (25) so as to suppress the play is connected in series with each other , and the set load of the auxiliary spring (52) is adjusted to the pressure adjusting spring (52). 25) A load response type brake hydraulic control valve, which is interposed smaller than that of the above 25) . Claim 1 wherein:
A retainer (36) having a cylindrical portion (36a) housed in the pressure adjusting spring (25) is interposed between the nut plate (33) and the pressure adjusting spring (25). A load-responsive brake hydraulic control valve, characterized in that an auxiliary spring (52) is housed in the above-mentioned configuration.

Images