Slide valve

Abstract

Slide valve (V3) comprising a valve element (111) and a cylinder (112) with a bore (112a) that accommodates the valve element (111) to be movable in an axial direction, and designed such that when the valve element (111) moves in an initial position in the axial direction relative to the cylinder (112), a supply valve port (Vi) formed between the valve element (111) and the cylinder (112) opens, thereby introducing a working fluid from a hydraulic pressure source (31) through the supply valve port (Vi) into a hydraulic chamber, wherein a throttle section (O3) is provided in a fluid channel formed between the supply valve port (Vi) and the hydraulic pressure source (31), or in a fluid channel formed between the supply valve port (Vi) and the hydraulic chamber, wherein the throttle section (O3) is designed such that the area of ​​an opening formed between the valve element (111) and the cylinder (112) is constant in a throttle effectiveness range extending from the initial position to a position where the magnitude of an axial movement of the valve element (111) from the initial position becomes equal to a predetermined value, and the area of ​​the opening increases in a throttle ineffective range where the magnitude of an axial movement of the valve element (111) exceeds the predetermined value. characterized by the fact that the throttle section (O3) is provided at a position axially offset by a predetermined amount from one end of a wall surface of the bore (112a) of the cylinder (112), the end of which forms the feed valve port (Vi); wherein the throttle section (O3) is formed by an outer circumferential surface of the valve element (111) and a cylindrical projection (112e1) having a predetermined thickness and extending along the entire circumference of an inner end of a connecting hole (112e) formed in the cylinder (112) and communicating with the bore (112a) of the cylinder (112) at its inner end; and wherein a recess (112g) is formed between the cylindrical projection (112e1) and the end of the wall surface of the bore (112a) of the cylinder (112), the end of which forms the feed valve port (Vi), and the connecting hole (112e) and the cylindrical projection (112e1) are formed by a tube (P) which is fluid-tightly joined to the cylinder (112).

Description

TECHNICAL AREA

[0001] The present invention relates to a slide valve or coil valve; for example, a slide element suitable for a hydraulic brake device of a vehicle. STATE OF THE ART

[0002] A slide valve suitable for a vehicle's hydraulic braking system is disclosed, for example, in JP 2002 - 310 309 A. The disclosed slide valve comprises a valve element (slide) and a cylinder (sleeve) which has a bore for accommodating the valve element so that it can move axially. This slide valve is designed such that when the valve element moves in an initial position in the axial direction relative to the cylinder, a supply valve port formed between the valve element and the cylinder opens, thereby introducing a working fluid from a hydraulic pressure source through the supply valve port into a hydraulic chamber.

[0003] JP 2006-183811A relates to a slide valve according to the preamble of claim 1. US 5682744A and US 4128112A relate to similar valves. SUMMARY OF THE INVENTION

[0004] Furthermore, in the slide valve disclosed in JP 2002-310309A, the flow rate of the working fluid, which is introduced from the hydraulic pressure source through the supply valve port into the hydraulic chamber, gradually increases as the opening area of ​​the supply valve port, formed between the valve element and the cylinder, gradually increases in accordance with the axial movement of the valve element. Therefore, when the degree of filling of the hydraulic chamber with working fluid reaches a certain level, a so-called oil impact (which causes various adverse effects on the device) can occur.

[0005] The present invention was made to limit the occurrence of the oil impact described above and provides a slide valve according to claim 1, comprising a valve element and a cylinder with a bore that accommodates the valve element to be movable in an axial direction, and designed such that when the valve element moves in an initial position in the axial direction relative to the cylinder, a supply valve port formed between the valve element and the cylinder opens, thereby introducing a working fluid from a hydraulic pressure source through the supply valve port into a hydraulic chamber, wherein a throttle section is provided in a fluid channel formed between the supply valve port and the hydraulic pressure source, or in a fluid channel formed between the supply valve port and the hydraulic chamber.wherein the throttle section is designed such that the area of ​​an opening formed between the valve element and the cylinder is constant in a throttle validity or effectiveness range extending from the initial position to a position where the magnitude of an axial movement of the valve element from the initial position becomes equal to a predetermined value, and the area of ​​the opening increases in a throttle invalidity or ineffectiveness range where the magnitude of an axial movement of the valve element exceeds the predetermined value.

[0006] In the spool valve of the present invention, the throttle section described above is provided in the fluid channel formed on the hydraulic pressure source side of the supply valve port or in the fluid channel formed on the hydraulic chamber side of the supply valve port. Therefore, if the spool valve is adjusted such that the fill level of the working fluid within the hydraulic chamber reaches a certain level within the throttle section's effective range, the flow rate of the working fluid supplied to the hydraulic chamber at the time the fill level of the working fluid within the hydraulic chamber reaches the certain level can be reduced compared to the case where the throttle section is not provided, thereby limiting the occurrence of oil impact within the hydraulic chamber.

[0007] In the slide valve of the present invention, the occurrence of an oil impact within the hydraulic chamber is limited by the throttle section, and in the throttle invalidity range, in which the axial movement of the valve element from the initial position exceeds the predetermined value, the opening area or the opening surface of the throttle section described above is increased.Therefore, it is possible to limit the increase in the amount of axial movement of the valve element relative to the cylinder when, compared to the case where a fixed throttle is provided in the fluid channel formed on the hydraulic pressure source side of the supply valve port, or in the fluid channel formed on the hydraulic chamber side of the supply valve port, in order to reduce the flow rate of the working fluid supplied to the hydraulic chamber at the time when the fill level of the working fluid within the hydraulic chamber reaches a certain level, so that no oil impact occurs (in this case, since the supply flow rate is reduced by the fixed throttle at all times, the amount (time) of axial movement of the valve element relative to the cylinder must be increased as needed to ensure the fluid supply quantity required in the hydraulic chamber).Therefore, it becomes possible to limit the increase in the overall length of the slide valve to a possible extent.

[0008] The present invention described above can be implemented such that the throttle section is provided at a position that is axially offset by a predetermined amount from one end of a wall surface of the bore of the cylinder, which end forms the feed valve port; wherein the throttle section is formed by an outer circumferential surface of the valve element and a cylindrical projection having a predetermined thickness and extending along the entire circumference of an inner end of a connecting hole formed in the cylinder and communicating with the bore of the cylinder at its inner end; and wherein a recess is formed between the cylindrical projection and the end of the wall surface of the bore of the cylinder, which end forms the feed valve port.In this case, the throttling range can be appropriately adjusted by adjusting the length of the recess in the axial direction. Furthermore, the connecting hole and the cylindrical projection can be formed by a tube or pipe that is fluid-tightly attached to the cylinder. In this case, the degree of throttling at the throttled section can be easily adjusted by changing the insertion depth (fitting) of the tube or pipe into the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a vertically cut side view schematically showing an unclaimed embodiment in which a slide valve according to the present invention is applied to a hydraulic brake device of a vehicle (a first, unclaimed embodiment of the slide valve according to the present invention). Fig. Figure 2 is a set of enlarged cross-sectional views of a main section of the slide valve, which is located in Fig. Figure 1 shows, where (a) shows a state when a valve element moves in the axial direction from its initial position and a throttle section starts its function or effect (at a time determined by So in Fig. 3 is shown), (b) shows a state in which the valve element is in the initial position, (c) shows a state in which the throttle section ceases its function or effect after the valve element has moved in the axial direction from the initial position by a predetermined amount (at a time specified by S1 in Fig. 3 is shown), and (d) shows a state after the magnitude of the axial movement of the valve element from the initial position has exceeded the predetermined magnitude. Fig. 3 is a diagram that schematically illustrates the relationship between the amount of movement of the valve element of the slide valve, which is in Fig. Figure 1 shows the flow rate of a fluid being supplied from a hydraulic pressure source to a hydraulic chamber. Fig. Figure 4 is a set of enlarged cross-sectional views of a main section of a slide valve, showing a modification of the slide valve of the first, unclaimed embodiment, which is described in Fig. 1 and Fig. Figure 2 shows a state in which the valve element is in its initial position, (b) shows a state when the valve element moves in the axial direction from its initial position and a throttle section begins its function or effect, (c) shows a state in which the throttle section functions or acts, and (d) shows a state after the magnitude of the axial movement of the valve element from the initial position has exceeded a predetermined amount. Fig. Figure 5 is an enlarged cross-sectional view of a main section of a second, unclaimed embodiment of the slide valve according to the present invention. Fig. Figure 6 is an enlarged cross-sectional view of a main section of a third claimed embodiment of the slide valve according to the present invention. Fig. Figure 7 is an enlarged cross-sectional view of a main section of a fourth, unclaimed embodiment of the slide valve according to the present invention. WAY TO EXECUTIVE THE INVENTION

[0009] Embodiments of the present invention will now be described with reference to the drawings. Fig. Figures 1 to 3 show a first, unclaimed embodiment of a slide valve or a coil valve according to the present invention. In a slide valve V1 according to the first, unclaimed embodiment, a valve element (coil or slide) 11 is received in a bore 12a of a cylinder (sleeve piston) 12 such that the valve element 11 is movable in the axial direction. When a brake pedal BP is depressed, the valve element 11 is pressed by an input shaft IS towards the left side in the drawings (towards the front of a vehicle).

[0010] The cylinder 12 is attached to a housing 21 to allow axial movement. A high-pressure chamber R1, a low-pressure chamber R2, and a hydraulic chamber R3 are formed within the housing 21. The high-pressure chamber R1 is always connected to a hydraulic pressure source (accumulator or storage device) 31. The low-pressure chamber R2 is always connected to a reservoir 32. The hydraulic chamber R3 is connected to either the high-pressure chamber R1 or the low-pressure chamber R2 as a result of actuation of the spool valve V1. The movements of the valve element 11 and the cylinder 12 to the left in the drawings are transmitted via a rod 41, a reaction rubber disc 42, an output shaft or a discharge shaft 43, etc., which are assembled on the cylinder 12, to a piston 51 of a master brake cylinder 50.

[0011] The slide valve V1 not only has the valve element 11 and the cylinder 12, but also a return spring 13, which is arranged between the valve element 11 and the cylinder 12 and forces the valve element 11 towards its initial position. As in Fig. As shown in Figure 2, the valve element 11 has shaft sections 11a, 11b with large diameters of the same diameter, a shaft section 11c with medium diameter, and shaft sections 11d, 11e, 11f with small diameters of the same diameter. The valve element 11 also has an annular groove 11g, an axial hole 11h, and connecting holes 11i, 11j.

[0012] The right-hand shaft section 11a with a large diameter is a section that is fitted into a right-hand end section 12a1 of the bore 12a of the cylinder 12 such that the shaft section 11a with a large diameter is axially sliding. The right-hand shaft section 11a with a large diameter forms a discharge valve port Vo in conjunction with the right-hand end section 12a1 of the bore 12a. The left-hand shaft section 11b with a large diameter is a section that is fitted into an intermediate section 12a2 of the bore 12a of the cylinder 12 such that the shaft section 11b with a large diameter is axially sliding. The left-hand shaft section 11b with a large diameter forms a feed valve port Vi in conjunction with the intermediate section 12a2 of the bore 12a.

[0013] The medium-diameter shaft section 11c is formed between the large-diameter shaft sections 11a and 11b and has a throttle-forming surface on its outer circumferential surface, which has a predetermined width. This throttle-forming surface, in conjunction with the wall surface of bore 12a in cylinder 12, forms a throttle section O1. The small-diameter right shaft section 11d is formed at the right end of the valve element 11 and is inserted into a stepped hole 12b in cylinder 12, located on the right side of the drawings, allowing the small-diameter shaft section 11d to move axially.The small-diameter central shaft section 11e is formed between the large-diameter shaft section 11a and the medium-diameter shaft section 11c of the valve element 11 and is axially movable within the bore 12a of the cylinder 12. The small-diameter left shaft section 11f is formed at the left end of the valve element 11 and is inserted into a stepped hole 12c of the cylinder 12, which is located on the left side in the drawings, so that the small-diameter shaft section 11f can move in the axial direction.

[0014] The axial hole 11h is formed coaxially with the center of the valve element 11. The axial hole 11h is open at its right end and closed at its left end. The right connecting hole 11i is formed in the small-diameter shaft section 11d to establish a continuous connection between the right stepped hole 12b and the axial hole 11h. The left connecting hole 11j is formed in the small-diameter shaft section 11f to establish a continuous connection between the left stepped hole 12c and the axial hole 11h.

[0015] The discharge valve port Vo is formed between the valve element 11 and the cylinder 12. When the valve element 11 is in a starting position (the position described in section (b) of Fig. (as shown in Figure 2), the discharge valve port Vo is open. When the valve element 11 moves axially in its initial position relative to the cylinder 12 against the thrust force of the return spring 13, the discharge valve port Vo closes (see sections (a), (c) and (d) of Figure 2). Fig. 2) The feed valve port Vi is formed between the valve element 11 and the cylinder 12. When the valve element 11 is in the initial position (the position described in section (b) of Fig. (as shown in Figure 2), the feed valve port Vi is closed. When the valve element 11 moves axially in its initial position relative to the cylinder 12 against the thrust force of the return spring 13, the feed valve port Vi opens after the discharge valve port Vo closes.

[0016] The throttle section O1 is provided in a fluid channel formed on the side of the hydraulic chamber R3 of the supply valve port Vi. The throttle section O1 is located at a position axially offset by a predetermined amount from one end of the outer circumferential surface of the valve element 11, which end forms the supply valve port Vi. The throttle section O1 is formed by the bore wall surface of the cylinder 12 and the throttle-forming surface formed on the outer circumferential surface of the valve element 11, which has a predetermined width (the outer circumferential surface of the shaft section 11c with mean diameter). In this throttle section O1, the area of ​​the opening formed between the valve element 11 and the cylinder 12 is constant within a throttle validity range that extends from the initial position.The initial position extends to a position where the axial movement of the valve element 11 from the initial position equals a predetermined value S1, and the opening range increases in a throttle invalidation range where the axial movement of the valve element 11 exceeds the predetermined value S1. The axial overlap between the bore wall surface of the cylinder 12 and the outer circumferential surface of the medium-diameter shaft section 11c, which forms the throttle section O1, is set such that the overlap gradually decreases near the predetermined value S1 and becomes zero at the predetermined value S1.

[0017] Cylinder 12 has bore 12a into which the large-diameter shaft sections 11a and 11b of the valve element 11 are fitted such that they can slide in the axial direction. Cylinder 12 also has stepped holes 12b and 12c formed at opposite ends of bore 12a. Furthermore, cylinder 12 has a connecting hole 12d for establishing a continuous connection between a right-hand end section of bore 12a (on the left side of the discharge valve port Vo) and hydraulic chamber R3, a connecting hole 12e for establishing a continuous connection between an intermediate section of bore 12a (on the left side of the supply valve port Vi) and high-pressure chamber R1, and a connecting hole 12f for establishing a continuous connection between a large-diameter section of stepped hole 12c and low-pressure chamber R2.

[0018] In the first, unclaimed embodiment, designed as described above, the supply valve port Vi opens after the discharge valve port Vo closes when the input shaft IS and the valve element 11 in the drawings are moved to the left from their initial (return) position as a result of the brake pedal BP being depressed. As a result, the connection between the hydraulic chamber R3 and the low-pressure chamber R2 is closed, and the connection between the hydraulic chamber R3 and the high-pressure chamber R1 is established, allowing high-pressure working fluid to flow from the high-pressure chamber R1 into the hydraulic chamber R3. Consequently, the cylinder 12 is pushed forward, and the piston 51 of the master cylinder 50 is pushed forward via the reaction rubber disc 42 and the output shaft 43, thus achieving the desired brake actuation.The introduction of the working fluid from the high-pressure chamber R1 into the hydraulic chamber R3 is carried out through the connecting hole 12e, the open supply valve connection Vi, the connecting hole 12d, etc.

[0019] Furthermore, in the first, unclaimed embodiment, the discharge valve port Vo in the slide valve V1 opens when the brake pedal BP is released after the supply valve port Vi closes. As a result, the connection between the hydraulic chamber R3 and the high-pressure chamber R1 is stopped, and the connection between the hydraulic chamber R3 and the low-pressure chamber R2 is established, allowing the working fluid to be discharged from the hydraulic chamber R3 into the low-pressure chamber R2. Consequently, the piston 51 of the master cylinder 50, the output shaft 43, the reaction rubber disc 42, the slide valve V1, etc., return to their initial positions, thereby releasing the brake actuation. The discharge of the working fluid from the hydraulic chamber R3 into the low-pressure chamber R2 is effected through the connecting hole 12d, the open discharge valve port Vo, the connecting hole 11i, the axial hole 11h, the connecting hole 11j, the connecting hole 12f, etc.

[0020] Incidentally, in the slide valve V1 of the first, unclaimed embodiment, the previously described throttling section O1 is provided in the fluid channel, which is formed on the side of the hydraulic chamber R3 of the supply valve connection Vi. Therefore, if the slide valve V1 is designed such that the fill level of the working fluid within the hydraulic chamber R3 reaches a certain level in the throttling validity or effectiveness range (see Fig. 3) of the throttle section O1, the flow rate of the working fluid supplied to the hydraulic chamber R3 at the time when the fill level of the working fluid within the hydraulic chamber R3 reaches the specified level is reduced compared to the case in which the throttle section O1 is not provided, thereby limiting the occurrence of an oil impact within the hydraulic chamber R3.

[0021] In the slide valve V1 of the first, unclaimed embodiment, the occurrence of an oil impact within the hydraulic chamber R3 is limited by the throttle section O1, and in the throttle invalidity or ineffectiveness range in which the axial movement of the valve element 11 from the initial position exceeds the predetermined value S1 (see Fig. 3) The opening range of the previously described throttle section O1 increases. Therefore, it is possible to limit the increase in the amount of axial movement of the valve element 11 relative to the cylinder 12 compared to the case where a fixed throttle is provided in the fluid channel formed on the hydraulic pressure source side of the supply valve port Vi, or in the fluid channel formed on the hydraulic chamber side of the supply valve port Vi, in order to reduce the flow rate of the working fluid supplied to the hydraulic chamber R3 at the time when the fill level of the working fluid in the hydraulic chamber R3 reaches a certain level, so that no oil impact occurs (in this case, since the supply flow rate is reduced by the fixed throttle).Since the fixed throttle is reduced at all times, the amount (time) of axial movement of the valve element relative to the cylinder must be increased as needed to ensure the fluid supply required in the hydraulic chamber R3. Therefore, it becomes possible to limit the increase in the overall length of the spool valve V1 to a manageable extent.

[0022] In the slide valve V1 of the first, unclaimed embodiment, the throttle section O1 is located at a position axially offset by a predetermined amount from the end of the outer circumferential surface (the large-diameter shaft section 11b) of the valve element 11, which end forms the supply valve port Vi. The throttle section O1 is formed by the wall surface of the bore 12a of the cylinder 12 and the throttle-forming surface, which is formed on the outer circumferential surface of the medium-diameter shaft section 11c of the valve element 11 and has a predetermined width. The annular groove 11g is formed between the end of the outer circumferential surface (the large-diameter shaft section 11b) of the valve element 11, which end forms the supply valve port Vi, and the throttle-forming surface (the medium-diameter shaft section 11c).Therefore, the throttle validity range can be appropriately adjusted by adjusting the length of the annular groove 11g in the axial direction.

[0023] In the slide valve V1 of the first, unclaimed embodiment, the annular groove 11g and the throttle section O1 are arranged such that, when the valve element 11 is in its initial position, the annular groove 11g and the throttle section O1 are located near the feed valve port Vi. However, as in the case of a modified, unclaimed embodiment, which in Fig. As shown in section 4, the present invention can be implemented such that when the valve element 11 is in the initial position (see section (a) of Fig. 4), the annular groove 11g and the throttle section O1 are spaced a predetermined distance from the feed valve port Vi. In the modified, unclaimed embodiment, which is described in Fig. 4 is shown, as in sections (a) of Fig. As shown in section 4, a valve section A is provided between the feed valve port Vi and the throttle section O1.

[0024] Valve section A is formed by providing an annular groove B on the wall surface of the bore 12a of the cylinder 12 and an annular groove C on the large-diameter shaft section 11b of the valve element 11, thereby ensuring a space D between the valve element 11 and the cylinder 12. Valve section A is closed when the valve element 11 is in its initial position (see section (a) of Fig. 4), and opens when the throttle section O1 starts to operate or take effect (see section (b) of Fig. 4) Therefore, in this modified, unclaimed embodiment, the hydraulic pressure changes stepwise between the supply valve port Vi and the throttle section O1 with the axial movement (movement to the left in Fig. 4) of the valve element 11. Accordingly, in this modified, unclaimed embodiment, the clearance tolerance or accuracy of the throttle section O1 can be relaxed compared with the first, unclaimed embodiment described above.

[0025] In the throttle section O1, which is in Fig. As shown in Figure 4, in the throttle validity or effectiveness range, which extends from the initial position to a position where the axial movement of the valve element 11 from the initial position becomes equal to the predetermined value S1, the area or surface of the opening formed between the valve element 11 and the cylinder 12 is constant (see sections (b) and (c) of Figure 4). Fig. 4) and in the throttle invalidity or ineffectiveness range, in which the axial movement of the valve element 11 exceeds the predetermined value S1, the opening range or opening area increases (see section (d) of Fig. 4) The amount of overlap in the axial direction between the bore wall surface of the cylinder 12 and the outer circumferential surface of the shaft section 11c with mean diameter, which forms the throttle section O1, is set such that the amount of overlap gradually decreases near the predetermined value S1 and becomes zero at the predetermined value S1.

[0026] In the slide valve V1 of the first, unclaimed embodiment, the previously described throttle section O1 is provided in the fluid channel, which is formed on the side of the hydraulic chamber R3 of the supply valve connection V1. However, as in the case of a slide valve V2 of a second, unclaimed embodiment, which in Fig. 5 shows a slide valve V3 of a third, claimed embodiment, which is in Fig. 6 is shown, or a slide valve V4 of a fourth, unclaimed embodiment, which is shown in Fig. As shown in Figure 7, a throttle section O2, O3, or O4 can be provided in the fluid channel, which is formed on the side of the hydraulic pressure source (high-pressure chamber R1) of the supply valve port Vi. Since the slide valve V2 of the second, unclaimed embodiment, which is shown in Figure 7, Fig. Figure 5 shows the slide valve V3 of the third, claimed embodiment, which is in Fig. 6 is shown, and the slide valve V4 of the fourth, unclaimed embodiment, which is shown in Fig. Figure 7 shows that the valves have essentially the same structure as the slide valve V1 of the first, unclaimed embodiment, except that the throttle sections O2, O3, and O4 differ in structure from the throttle section O1, and that a tapered section 111k is formed between a large-diameter shaft section 111b and a small-diameter shaft section 111e of a valve element 111, such that the diameter of the tapered section 111k decreases towards the small-diameter shaft section. Therefore, the structures of the slide valves V2, V3, and V4 are not described here.

[0027] The throttle section O2 of the second, unclaimed embodiment, which is in Fig. Figure 5 shows a position axially offset by a predetermined amount from one end of the wall surface of a bore 112a of a cylinder 112, which end forms the feed valve port Vi. The throttle section O2 is formed by the outer circumferential surface of the large-diameter shaft section 111b of the valve element 111 and a cylindrical projection 112e1, which has a predetermined thickness and extends along the entire circumference of the inner end of a connecting hole 112e. The connecting hole 112e is formed in the cylinder 112 and communicates with the bore 112a of the cylinder 112 at its inner end. Furthermore, in the second, unclaimed embodiment, which is shown in Figure 5, the throttle section O2 is formed by the outer circumferential surface of the large-diameter shaft section 111b of the valve element 111 and a cylindrical projection 112e1, which has a predetermined thickness and extends along the entire circumference of the inner end of a connecting hole 112e. The connecting hole 112e is formed in the cylinder 112 and communicates with the bore 112a of the cylinder 112 at its inner end. Fig. As shown in Figure 5, a recess 112g is formed between the cylindrical projection 112e1 and the end of the wall surface of the bore 112a of the cylinder 112, the end of which forms the feed valve connection Vi. Therefore, the throttle range can be appropriately adjusted by adjusting the length of the recess 112g in the axial direction.

[0028] In the throttle section O3 of the third, claimed embodiment, which is in Fig. As shown in Figure 6, the connecting hole 112e and the cylindrical projection 112e1 are formed by a tube or line P, which is provided or joined to the cylinder 112 in a liquid-tight manner. Since the structure of the remaining part is essentially identical to that of the throttle section O2 of the second, unclaimed embodiment, which is shown in Figure 6, the following applies: Fig. Figure 5 shows the description of which is omitted. In this third, claimed embodiment, the degree of throttling at the throttle section O3 can be easily adjusted by changing (adjusting) the amount of insertion (fitting) of the tube or line P into the cylinder 112.

[0029] The throttle section O4 of the fourth, unclaimed embodiment, which is in Fig. As shown in Figure 5, the valve element is located at a position axially offset by a predetermined amount from the end of the wall surface of the bore 112a of the cylinder 112, the end of which forms the supply valve port Vi. The throttle section O4 is formed by the outer circumferential surface of the large-diameter shaft section 111b of the valve element 111 and a flange-shaped projection 112e1. The projection 112e1 extends from the wall surface of the bore 112a of the cylinder 112 to the outer circumferential surface of the valve element 111 at a position between the inner end of the connecting hole 112e, which is formed in the cylinder 112 and communicates with the bore 112a of the cylinder 112 at its inner end, and the end of the wall surface of the bore 112a of the cylinder 112, the end of which forms the supply valve port Vi. The flange-shaped projection 112e1 has a predetermined width and extends in a ring shape around the axis of the valve element 111.Furthermore, in the fourth, unclaimed embodiment, which is described in . Fig. As shown in Figure 7, the annular recess 112g is formed between the flange-shaped projection 112e1 and the end of the wall surface of the bore 112a of the cylinder 112, the end of which forms the feed valve connection Vi. Therefore, the throttle range can be appropriately adjusted by adjusting the length of the recess 112g in the axial direction.

[0030] In the slide valve V2 of the second, unclaimed embodiment, which is in Fig. 5 shows the slide valve V3 of the third, claimed embodiment, which is in Fig. 6 is shown, and the slide valve V4 of the fourth, unclaimed embodiment, which is shown in Fig.As shown in Figure 7, the tapered section 111k, which tapers towards the small-diameter shaft section 111e, is formed between the large-diameter shaft section 111b and the small-diameter shaft section 111e of the valve element 111. Therefore, the rate gradient of the supply flow in the throttle invalidation region can be reduced compared to the first, unclaimed embodiment. Furthermore, such a design (formation of a tapered section or a conical section between the large- and small-diameter shaft sections of the valve element, such that the diameter of the tapered section decreases towards the small-diameter shaft section) can be similarly applied in the first, unclaimed embodiment.

[0031] In the embodiments described above, the present invention is implemented such that, as a result of an axial movement of the valve element 11 from its initial position relative to the cylinder 12, the feed valve port Vi opens after the discharge valve port Vo, which is formed between the valve element 11 and the cylinder 12, closes. However, the timing at which the feed valve port (Vi) opens can be freely changed. For example, the slide valve of the present invention can be designed such that the feed valve port opens simultaneously with the closing of the discharge valve port, or it can be designed such that the feed valve port opens (immediately) before the discharge valve port closes.

Claims

[1] Slide valve (V3) comprising a valve element (111) and a cylinder (112) with a bore (112a) which accommodates the valve element (111) to be movable in an axial direction, and which is designed such that when the valve element (111) moves in an initial position in the axial direction relative to the cylinder (112), a supply valve port (Vi) formed between the valve element (111) and the cylinder (112) opens, thereby introducing a working fluid from a hydraulic pressure source (31) through the supply valve port (Vi) into a hydraulic chamber, wherein a throttle section (O3) is provided in a fluid channel formed between the supply valve port (Vi) and the hydraulic pressure source (31), or in a fluid channel formed between the supply valve port (Vi) and the hydraulic chamber, wherein the throttle section (O3) is designed such that the area of ​​an opening formed between the valve element (111) and the cylinder (112) is constant in a throttle effectiveness range extending from the initial position to a position where the magnitude of an axial movement of the valve element (111) from the initial position becomes equal to a predetermined value, and the area of ​​the opening increases in a throttle ineffective range where the magnitude of an axial movement of the valve element (111) exceeds the predetermined value, characterized by , that the throttle section (O3) is provided at a position axially offset by a predetermined amount from one end of a wall surface of the bore (112a) of the cylinder (112), the end of which forms the feed valve port (Vi); wherein the throttle section (O3) is formed by an outer circumferential surface of the valve element (111) and a cylindrical projection (112e1) having a predetermined thickness and extending along the entire circumference of an inner end of a connecting hole (112e) formed in the cylinder (112) and communicating with the bore (112a) of the cylinder (112) at its inner end; and wherein a recess (112g) is formed between the cylindrical projection (112e1) and the end of the wall surface of the bore (112a) of the cylinder (112), the end of which forms the feed valve port (Vi), and the connecting hole (112e) and the cylindrical projection (112e1) are formed by a tube (P) which is fluid-tightly joined to the cylinder (112).

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