ACTUATOR UNIT FOR CONTROLLING HYDRAULIC PUMP

• US 20170307075A1
• Filed: 07/14/2017
• Published: 10/26/2017
• Est. Priority Date: 08/07/2014
• Status: Active Grant

• Current Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd. (Yanmar Holdings Co., Ltd.)
• Original Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd. (Yanmar Holdings Co., Ltd.)
• Inventors: MATSUURA, Jun, Iwaki, Koji, Tsuji, Tomoyuki, Kamada, Minoru, Kanenobu, Hideki, Sasahara, Kengo
• Granted Patent: US 10,641,389 B2
• Time in Patent Office: Days
• CPC Class Codes: F04B 1/00 Multi-cylinder machines or pumps characterised by number or arrangement of cylinders machines or pumps with pistons coacting within one cylinder F04B3/00
• CPC Class Codes: F04B 23/04 Combinations of two or more pumps
• CPC Class Codes: F16H 39/04 with liquid motor and pump combined in one unit
• CPC Class Codes: F16H 47/02 the fluid gearing being of the volumetric type
• CPC Class Codes: F16H 61/4069 Valves related to the control of neutral, e.g. shut off valves
• CPC Class Codes: F16H 61/431 Pump capacity control by electro-hydraulic control means, e.g. using solenoid valves

Abstract

An HST control mechanism includes a rotary member, a servo unit, a telescopic member, and a biasing device. The rotary member for controlling a displacement of a hydrostatic transmission (HST) is pivoted outside of a casing incorporating the HST. The servo unit includes a telescopically movable actuator and a valve controlling the telescopic movement of the actuator. The actuator is interlockingly connected to the rotary member. The servo unit is pivotally supported on the casing via a first pivot. The servo unit rotates centered on the first pivot as the rotary member rotates according to the telescopic movement of the actuator hydraulically controlled by the valve. The telescopic member is pivotally supported on the casing via a second pivot. The telescopic member is provided with the biasing device that biases the telescopic member and the rotary member toward a position corresponding to a neutral state of the HST.

Claims

1. An actuator unit for controlling a hydraulic pump, the actuator unit comprising:

an actuator for controlling a rotational position of a displacement control member of the hydraulic pump;

a connection member connected to the actuator, the connection member being formed with a recess and a boss extended coaxially to the recess,

wherein a tip portion of a trunnion shaft serving as a pivotal shaft of the displacement control member is fitted into the recess; and

a fastener passed through the boss to engage with the tip portion of the trunnion shaft in the recess so as to fasten the trunnion shaft to the connection member.

2. The actuator unit according to claim 1,

wherein the recess and the tip portion of the trunnion shaft are tapered.

3. The actuator unit according to claim 1,

wherein the actuator is a piston in a hydraulic cylinder, and

wherein the hydraulic pump controlling actuator unit is a servo unit including the hydraulic cylinder incorporating the piston serving as the actuator.

4. The actuator unit according to claim 3,

wherein the trunnion shaft includes a fluid passage through which a part of fluid supplied to the hydraulic cylinder is supplied as lubricating fluid to the trunnion shaft fastened to the connection member.